BuildManager.cs source code in C# .NET

Source code for the .NET framework in C#

                        

Code:

/ Dotnetfx_Vista_SP2 / Dotnetfx_Vista_SP2 / 8.0.50727.4016 / DEVDIV / depot / DevDiv / releases / whidbey / NetFxQFE / ndp / fx / src / xsp / System / Web / Compilation / BuildManager.cs / 1 / BuildManager.cs

                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

/************************************************************************************************************/ 
 

 
namespace System.Web.Compilation {

using System;
using System.IO; 
using System.Collections;
using System.Collections.Generic; 
using System.Collections.Specialized; 
using System.Reflection;
using System.Runtime.Remoting.Messaging; 
using System.Text;
using System.Xml;
using System.Globalization;
using System.Resources; 
using System.CodeDom;
using System.CodeDom.Compiler; 
using System.Configuration; 
using System.Web.Configuration;
using System.Web.Util; 
using System.Web.Caching;
using System.Web.UI;
#if ORCAS
using System.Web.UI.Imaging; 
#endif
using System.Web.Hosting; 
using System.Web.Profile; 
using System.Web.Security;
using System.Threading; 
using System.Security.Permissions;
using System.Web.Management;

 
/// 
///     
///       IProvider compilation related services 
///    
///  
[AspNetHostingPermission(SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Medium)]
public sealed class BuildManager {

    /// Contants relating to generated assembly names 

    // All generated assemblies start with this prefix 
    internal const string AssemblyNamePrefix = "App_"; 

    // Web assemblies are the assemblies generated from web files (aspx, ascx, ...) 
    internal const string WebAssemblyNamePrefix = AssemblyNamePrefix + "Web_";

    internal const string AppThemeAssemblyNamePrefix = AssemblyNamePrefix + "Theme_";
    internal const string GlobalThemeAssemblyNamePrefix = AssemblyNamePrefix + "GlobalTheme_"; 
    internal const string AppBrowserCapAssemblyNamePrefix = AssemblyNamePrefix + "Browsers";
 
    private const string CodeDirectoryAssemblyName = AssemblyNamePrefix + "Code"; 
    internal const string SubCodeDirectoryAssemblyNamePrefix = AssemblyNamePrefix + "SubCode_";
    private const string ResourcesDirectoryAssemblyName = AssemblyNamePrefix + "GlobalResources"; 
    private const string LocalResourcesDirectoryAssemblyName = AssemblyNamePrefix + "LocalResources";
    private const string WebRefDirectoryAssemblyName = AssemblyNamePrefix + "WebReferences";
    internal const string GlobalAsaxAssemblyName = AssemblyNamePrefix + HttpApplicationFactory.applicationFileName;
 
    private const string LicensesAssemblyName = AssemblyNamePrefix + "Licenses";
 
    internal const string UpdatableInheritReplacementToken = "__ASPNET_INHERITS"; 

    private static System.Security.Cryptography.RNGCryptoServiceProvider _rng = new System.Security.Cryptography.RNGCryptoServiceProvider(); 
    private static bool _theBuildManagerInitialized;
    private static Exception _initializeException;
    private static BuildManager _theBuildManager = new BuildManager();  // single instance of the class
    private static long s_topLevelHash; 
    internal static BuildManager TheBuildManager { get { return _theBuildManager; } }
 
    // Precompilation related fields 
    private const string precompMarkerFileName = "PrecompiledApp.config";
    private string _precompTargetPhysicalDir; 
    private PrecompilationFlags _precompilationFlags;
    private bool _isPrecompiledApp;
    private bool _isPrecompiledAppComputed;
    private bool _isUpdatablePrecompiledApp; 
    private bool _precompilingApp;  // we're in the process of precompiling an app
 
    private string _strongNameKeyFile; 
    private string _strongNameKeyContainer;
 
    private bool _optimizeCompilations;
    internal static bool OptimizeCompilations {
        get { return _theBuildManager._optimizeCompilations; }
    } 

    // filepath to the generated web.hash file, This file should only be re-created when 
    // the appdomain is restarted and the top-level generated assemblies need to be recompiled. 
    private string _webHashFilePath;
    internal static String WebHashFilePath { 
        get { return _theBuildManager._webHashFilePath; }
    }

    private BuildResultCache[] _caches; 
    private MemoryBuildResultCache _memoryCache;
 
    private bool _topLevelFilesCompiledStarted; 
    private bool _topLevelFilesCompiledCompleted;
    private Exception _topLevelFileCompilationException; 

    private BuildResultCompiledGlobalAsaxType _globalAsaxBuildResult;
    private Type _profileType;
 
    // Special top level directories that are treated differently from regular web directories
    // during precompilation (e.g. App_Code) 
    private StringSet _excludedTopLevelDirectories; 

    // Directories that are not requestable 
    private StringSet _forbiddenTopLevelDirectories;

    private StringSet _excludedCodeSubdirectories;
 
    private CompilationStage _compilationStage = CompilationStage.PreTopLevelFiles;
    internal static CompilationStage CompilationStage { get { return _theBuildManager._compilationStage; } } 
 
    private VirtualPath _scriptVirtualDir;
    private VirtualPath _globalAsaxVirtualPath; 
    internal static VirtualPath ScriptVirtualDir { get { return _theBuildManager._scriptVirtualDir; } }
    internal static VirtualPath GlobalAsaxVirtualPath { get { return _theBuildManager._globalAsaxVirtualPath; } }

    private BuildManager() { } 

    internal static bool InitializeBuildManager() { 
 
        // If we already tried and got an exception, just rethrow it
        if (_initializeException != null) { 
            // We need to wrap it in a new exception, otherwise we lose the original stack.
            throw new HttpException(_initializeException.Message, _initializeException);
        }
 
        if (!_theBuildManagerInitialized) {
 
            // If Fusion was not yet initialized, skip the init. 
            // This can happen when there is a very early failure (e.g. see VSWhidbey 137366)
            Debug.Trace("BuildManager", "InitializeBuildManager " + HttpRuntime.FusionInited); 
            if (!HttpRuntime.FusionInited)
                return false;

            // Likewise, if the trust level has not yet been determined, skip the init (VSWhidbey 422311) 
            if (HttpRuntime.TrustLevel == null)
                return false; 
 
            _theBuildManagerInitialized = true;
            try { 
                _theBuildManager.Initialize();
            }
            catch (Exception e) {
                _theBuildManagerInitialized = false; 
                _initializeException = e;
                throw; 
            } 
        }
 
        return true;
    }

    private ClientBuildManagerCallback _cbmCallback; 
    internal static ClientBuildManagerCallback CBMCallback { get { return _theBuildManager._cbmCallback; } }
 
    private static bool _parseErrorReported; 
    internal static void ReportParseError(ParserError parseError) {
        // If there is a CBM callback, inform it of the error 
        if (BuildManager.CBMCallback != null) {
            _parseErrorReported = true;
            BuildManager.CBMCallback.ReportParseError(parseError);
        } 
    }
 
    private void ReportTopLevelCompilationException() { 
        Debug.Assert(_topLevelFileCompilationException != null);
 
        // Try to report the cached error to the CBM callback
        ReportErrorsFromException(_topLevelFileCompilationException);

        // We need to wrap it in a new exception, otherwise we lose the original stack. 
        throw new HttpException(_topLevelFileCompilationException.Message,
            _topLevelFileCompilationException); 
    } 

    // Given an exception, attempt to turn it into calls to the CBM callback 
    private void ReportErrorsFromException(Exception e) {
        // If there is no CBM callback, nothing to do
        if (BuildManager.CBMCallback == null)
            return; 

        // Call the CBM callback as appropriate, based on the type of exception 
 
        if (e is HttpCompileException) {
            CompilerResults results = ((HttpCompileException) e).Results; 
            foreach (CompilerError error in results.Errors) {
                BuildManager.CBMCallback.ReportCompilerError(error);
            }
        } 
        else if (e is HttpParseException) {
            foreach (ParserError parseError in ((HttpParseException)e).ParserErrors) { 
                ReportParseError(parseError); 
            }
        } 
    }

    // The assemblies produced from the code directories and global.asax, which
    // every other compilation will linked with. 
    private List _topLevelReferencedAssemblies;
    private List TopLevelReferencedAssemblies { get { return _topLevelReferencedAssemblies; } } 
 
    private Dictionary _topLevelAssembliesIndexTable;
    private IDictionary TopLevelAssembliesIndexTable { get { return _topLevelAssembliesIndexTable; } } 

    private Dictionary _generatedFileTable;
    internal static Dictionary GenerateFileTable {
        get { 
            if (_theBuildManager._generatedFileTable == null) {
                _theBuildManager._generatedFileTable = new Dictionary(StringComparer.OrdinalIgnoreCase); 
            } 

            return _theBuildManager._generatedFileTable; 
        }
    }

    private ArrayList _codeAssemblies; 
    public static IList CodeAssemblies {
        get { 
            _theBuildManager.EnsureTopLevelFilesCompiled(); 
            return _theBuildManager._codeAssemblies;
        } 
    }

    private IDictionary _assemblyResolveMapping;
 
    private Assembly _appResourcesAssembly;
    internal static Assembly AppResourcesAssembly { get { return _theBuildManager._appResourcesAssembly; } } 
 
    // Indicates whether the parsers should coninue processing for more errors.
    // This is used in both CBM precompile-web, precompile-page and aspnet_compiler tool. 
    private bool _throwOnFirstParseError = true;
    internal static bool ThrowOnFirstParseError {
        get { return _theBuildManager._throwOnFirstParseError; }
        set { _theBuildManager._throwOnFirstParseError = value; } 
    }
 
    // Marks whether we are in the middle of performing precompilation, which affects how 
    // we deal with error handling and batching
    private bool _performingPrecompilation = false; 
    internal static bool PerformingPrecompilation {
        get { return _theBuildManager._performingPrecompilation; }
        set { _theBuildManager._performingPrecompilation = value; }
    } 

    private bool _skipTopLevelCompilationExceptions; 
    internal static bool SkipTopLevelCompilationExceptions { 
        get { return _theBuildManager._skipTopLevelCompilationExceptions; }
        set { _theBuildManager._skipTopLevelCompilationExceptions = value; } 
    }

    /*
     * Return the list of assemblies that a compilation needs to reference for a given 
     * config minus the assemblies indexed later than removeIndex
     */ 
    internal static ICollection GetReferencedAssemblies(CompilationSection compConfig, int removeIndex) { 

        AssemblySet referencedAssemblies = new AssemblySet(); 

        // Add all the config assemblies to the list
        foreach (AssemblyInfo a in compConfig.Assemblies) {
            Assembly[] assemblies = a.AssemblyInternal; 
            if (assemblies == null)
            { 
                lock (compConfig) 
                {
                    assemblies = a.AssemblyInternal; 
                    if (assemblies == null)
                        assemblies = a.AssemblyInternal = compConfig.LoadAssembly(a);
                }
            } 

            for (int i = 0; i < assemblies.Length; i++) 
            { 
                if (assemblies[i] != null) {
                    referencedAssemblies.Add(assemblies[i]); 
                }
            }
        }
 
        // Clone the top level referenced assemblies (code + global.asax + etc...), up to the removeIndex
        for (int i = 0; i < removeIndex; i++) { 
            referencedAssemblies.Add(TheBuildManager.TopLevelReferencedAssemblies[i]); 
        }
 
        return referencedAssemblies;
    }

    internal static ICollection GetReferencedAssemblies(CompilationSection compConfig) { 

        // Start by cloning the top level referenced assemblies (code + global.asax + etc...) 
        AssemblySet referencedAssemblies = AssemblySet.Create( 
            TheBuildManager.TopLevelReferencedAssemblies);
 
        // Add all the config assemblies to the list
        foreach (AssemblyInfo a in compConfig.Assemblies) {
            Assembly[] assemblies = a.AssemblyInternal;
            if (assemblies == null) 
            {
                lock (compConfig) 
                { 
                    assemblies = a.AssemblyInternal;
                    if (assemblies == null) 
                        assemblies = a.AssemblyInternal = compConfig.LoadAssembly(a);
                }
            }
 
            for (int i = 0; i < assemblies.Length; i++) {
                if (assemblies[i] != null) { 
                    referencedAssemblies.Add(assemblies[i]); 
                }
            } 
        }

        return referencedAssemblies;
    } 

 
    /* 
     * Return the list of assemblies that all page compilations need to reference. This includes
     * config assemblies ( section), bin assemblies and assemblies built from the 
     * app App_Code and other top level folders.
     */

    ///  
    /// Returns the assemblies referenced at the root application level of the current app
    ///  
    public static ICollection GetReferencedAssemblies() { 
        RuntimeConfig appConfig = RuntimeConfig.GetAppConfig();
        CompilationSection compConfig = appConfig.Compilation; 

        _theBuildManager.EnsureTopLevelFilesCompiled();

        return GetReferencedAssemblies(compConfig); 
    }
 
    /* 
     * Perform initialization work that should only be done once (per app domain).
     */ 
    private void Initialize() {

        Debug.Assert(_caches == null);
 
        // Register an AssemblyResolve event
        AppDomain.CurrentDomain.AssemblyResolve += new ResolveEventHandler(this.ResolveAssembly); 
 
        _globalAsaxVirtualPath = HttpRuntime.AppDomainAppVirtualPathObject.SimpleCombine(
            HttpApplicationFactory.applicationFileName); 

        _webHashFilePath = Path.Combine(HttpRuntime.CodegenDirInternal, "hash\\hash.web");

        // Indicate whether we should ignore the top level compilation exceptions. 
        // In CBM case, we want to continue processing the page and return partial info even
        // if the code files fail to compile. 
        _skipTopLevelCompilationExceptions = BuildManagerHost.InClientBuildManager; 

        // Deal with precompilation if we're in that mode 
        SetPrecompilationInfo(HostingEnvironment.HostingParameters);

        // The init code depends on whether we're precompiling or running an app
        if (_precompTargetPhysicalDir != null) { 

            // If the app is already precompiled, fail 
            FailIfPrecompiledApp(); 

            PrecompilationModeInitialize(); 
        }
        else {
            // Check if this application has been precompiled by aspnet_compiler.exe
            if (IsPrecompiledApp) { 
                PrecompiledAppRuntimeModeInitialize();
            } 
            else { 
                RegularAppRuntimeModeInitialize();
            } 
        }

        _scriptVirtualDir = Util.GetScriptLocation();
 
        // Top level directories that have a special semantic
        _excludedTopLevelDirectories = new CaseInsensitiveStringSet(); 
        _excludedTopLevelDirectories.Add(HttpRuntime.BinDirectoryName); 
        _excludedTopLevelDirectories.Add(HttpRuntime.CodeDirectoryName);
        _excludedTopLevelDirectories.Add(HttpRuntime.ResourcesDirectoryName); 
        _excludedTopLevelDirectories.Add(HttpRuntime.LocalResourcesDirectoryName);
        _excludedTopLevelDirectories.Add(HttpRuntime.WebRefDirectoryName);
        _excludedTopLevelDirectories.Add(HttpRuntime.ThemesDirectoryName);
 
        // Top level directories that are not requestable
        // It's the same as _excludedTopLevelDirectories, except that we allow 
        // the bin directory to avoid a v1 breaking change (VSWhidbey 465018) 
        _forbiddenTopLevelDirectories = new CaseInsensitiveStringSet();
        _forbiddenTopLevelDirectories.Add(HttpRuntime.CodeDirectoryName); 
        _forbiddenTopLevelDirectories.Add(HttpRuntime.ResourcesDirectoryName);
        _forbiddenTopLevelDirectories.Add(HttpRuntime.LocalResourcesDirectoryName);
        _forbiddenTopLevelDirectories.Add(HttpRuntime.WebRefDirectoryName);
        _forbiddenTopLevelDirectories.Add(HttpRuntime.ThemesDirectoryName); 

        LoadLicensesAssemblyIfExists(); 
    } 

    /* 
     * Init code used when we are running a non-precompiled app
     */
    private void RegularAppRuntimeModeInitialize() {
 
        //
        // Initialize the caches 
        // 

        // Always try the memory cache first 
        _memoryCache = new MemoryBuildResultCache(HttpRuntime.CacheInternal);

        // Use the standard disk cache for regular apps
        StandardDiskBuildResultCache diskCache = new StandardDiskBuildResultCache( 
            HttpRuntime.CodegenDirInternal);
 
        _caches = new BuildResultCache[] { _memoryCache, diskCache }; 

        CheckTopLevelFilesUpToDate(diskCache); 
    }

    /*
     * Init code used when we are running a precompiled app 
     */
    private void PrecompiledAppRuntimeModeInitialize() { 
 
        //
        // Initialize the caches 
        //

        // Always try the memory cache first
        _memoryCache = new MemoryBuildResultCache(HttpRuntime.CacheInternal); 

        // Used the precomp cache for precompiled apps 
        BuildResultCache preCompCache = new PrecompiledSiteDiskBuildResultCache( 
            HttpRuntime.BinDirectoryInternal);
 
        // Also create a regular disk cache so that we can compile and cache additional things.
        // This is useful even in non-updatable precomp, to cache DefaultWsdlHelpGenerator.aspx.

        StandardDiskBuildResultCache diskCache = new StandardDiskBuildResultCache( 
            HttpRuntime.CodegenDirInternal);
 
        _caches = new BuildResultCache[] { _memoryCache, preCompCache, diskCache }; 

        CheckTopLevelFilesUpToDate(diskCache); 
    }

    /*
     * Init code used when we are precompiling an app 
     */
    private void PrecompilationModeInitialize() { 
 
        // We are precompiling an app
 
        // Always try the memory cache first
        _memoryCache = new MemoryBuildResultCache(HttpRuntime.CacheInternal);

        // Create a regular disk cache, to take advantage of the fact that the app 
        // may already have been compiled (and to cause it to be if it wasn't)
        StandardDiskBuildResultCache diskCache = new StandardDiskBuildResultCache( 
            HttpRuntime.CodegenDirInternal); 

        // Create a special disk cache in the target's bin directory.  Use a slightly different 
        // implementation for the updatable case.
        string targetBinDir = Path.Combine(_precompTargetPhysicalDir, HttpRuntime.BinDirectoryName);
        BuildResultCache preCompilationCache;
        if (PrecompilingForUpdatableDeployment) { 
            preCompilationCache = new UpdatablePrecompilerDiskBuildResultCache(targetBinDir);
        } 
        else { 
            preCompilationCache = new PrecompilerDiskBuildResultCache(targetBinDir);
        } 

        _caches = new BuildResultCache[] { _memoryCache, preCompilationCache, diskCache  };

        CheckTopLevelFilesUpToDate(diskCache); 
    }
 
    // Load the licenses assembly from the bin dir if it exists (DevDiv 42149) 
    private void LoadLicensesAssemblyIfExists() {
        string licAssemblyPath = Path.Combine(HttpRuntime.BinDirectoryInternal, LicensesAssemblyName + ".dll"); 
        if (File.Exists(licAssemblyPath)) {
            Assembly.Load(LicensesAssemblyName);
        }
    } 

    private void CheckTopLevelFilesUpToDate(StandardDiskBuildResultCache diskCache) { 
 
        bool gotLock = false;
 
        try {
            // Grab the compilation mutex, since this method accesses the codegen files
            CompilationLock.GetLock(ref gotLock);
 
            CheckTopLevelFilesUpToDate2(diskCache);
        } 
        finally { 
            // Always release the mutex if we had taken it
            if (gotLock) { 
                CompilationLock.ReleaseLock();
            }
        }
    } 

    /* 
     * Check if the top level files are up to date, and cleanup the codegendir 
     * if they are not.
     */ 
    private void CheckTopLevelFilesUpToDate2(StandardDiskBuildResultCache diskCache) {

        long specialFilesCombinedHash = diskCache.GetPreservedSpecialFilesCombinedHash();
        Debug.Trace("BuildManager", "specialFilesCombinedHash=" + specialFilesCombinedHash); 

        // Delete all the non essential files left over in the codegen dir, unless 
        // specialFilesCombinedHash is 0, in which case we delete *everything* further down 
        if (specialFilesCombinedHash != 0)
            diskCache.RemoveOldTempFiles(); 

        // Use a HashCodeCombiner object to handle the time stamps of all the 'special'
        // files and directories that all compilations depend on:
        // - System.Web.dll (in case there is a newer version of ASP.NET) 
        // - ~\Bin directory
        // - ~\Resource directory 
        // - ~\WebReferences directory 
        // - ~\Code directory
        // - global.asax 

        HashCodeCombiner specialFilesDateTimeCombiner = new HashCodeCombiner();

        // Add a check for the app's physical path, in case it changes (ASURT 12975) 
        specialFilesDateTimeCombiner.AddObject(HttpRuntime.AppDomainAppPathInternal);
 
        // Process System.Web.dll 
        string aspBinaryFileName = typeof(HttpRuntime).Module.FullyQualifiedName;
        specialFilesDateTimeCombiner.AddFile(aspBinaryFileName); 

        // Process machine.config
        string machineConfigFileName = HttpConfigurationSystem.MachineConfigurationFilePath;
        specialFilesDateTimeCombiner.AddFile(machineConfigFileName); 

        // Process root web.config 
        string rootWebConfigFileName = HttpConfigurationSystem.RootWebConfigurationFilePath; 
        specialFilesDateTimeCombiner.AddFile(rootWebConfigFileName);
 
        RuntimeConfig appConfig = RuntimeConfig.GetAppConfig();
        CompilationSection compConfig = appConfig.Compilation;

        // Ignore the OptimizeCompilations flag in ClientBuildManager mode 
        if (!BuildManagerHost.InClientBuildManager) {
            _optimizeCompilations = compConfig.OptimizeCompilations; 
        } 

        // In optimized compilation mode, we don't clean out all the compilations just because a top level 
        // file changes.  Instead, we let already compiled pages run against the newer top level binaries.
        // In can be incorrect in some cases (e.g. return type of method changes from int to short), which is
        // why the optimization is optional
        if (!OptimizeCompilations) { 
            // Add a dependency of the bin, resources, webresources and code directories
            string binPhysicalDir = HttpRuntime.BinDirectoryInternal; 
            specialFilesDateTimeCombiner.AddDirectory(binPhysicalDir); 

            // Note that we call AddResourcesDirectory instead of AddDirectory, since we only want 
            // culture neutral files to be taken into account (VSWhidbey 359029)
            specialFilesDateTimeCombiner.AddResourcesDirectory(HttpRuntime.ResourcesDirectoryVirtualPath.MapPathInternal());

            specialFilesDateTimeCombiner.AddDirectory(HttpRuntime.WebRefDirectoryVirtualPath.MapPathInternal()); 

            specialFilesDateTimeCombiner.AddDirectory(HttpRuntime.CodeDirectoryVirtualPath.MapPathInternal()); 
 
            // Add a dependency on the global asax file.
            specialFilesDateTimeCombiner.AddFile(GlobalAsaxVirtualPath.MapPathInternal()); 
        }

        // Add a dependency on the hash of the app level  section, since it
        // affects all compilations, including the code directory.  It it changes, 
        // we may as well, start all over.
        specialFilesDateTimeCombiner.AddObject(compConfig.RecompilationHash); 
 
        ProfileSection profileSection = appConfig.Profile;
        specialFilesDateTimeCombiner.AddObject(profileSection.RecompilationHash); 

        // Add a dependency on file encoding (DevDiv 4560)
        specialFilesDateTimeCombiner.AddObject(appConfig.Globalization.FileEncoding);
 
        // Also add a dependency on the  config section
        TrustSection casConfig = appConfig.Trust; 
        specialFilesDateTimeCombiner.AddObject(casConfig.Level); 
        specialFilesDateTimeCombiner.AddObject(casConfig.OriginUrl);
 
        // Add a dependency on whether profile is enabled
        specialFilesDateTimeCombiner.AddObject(ProfileManager.Enabled);

        // Add a dependency to the force debug flag. 
        specialFilesDateTimeCombiner.AddObject(PrecompilingWithDebugInfo);
 
        // Store the top level hash 
        s_topLevelHash = specialFilesDateTimeCombiner.CombinedHash;
 
        if (PrecompilingForCleanBuild || specialFilesDateTimeCombiner.CombinedHash != specialFilesCombinedHash) {
            if (PrecompilingForCleanBuild) {
                Debug.Trace("BuildManager", "Precompiling for clean build.");
            } 
            else {
                Debug.Trace("BuildManager", "EnsureFirstTimeInit: hash codes don't match.  Old=" + 
                    specialFilesCombinedHash + " New=" + specialFilesDateTimeCombiner.CombinedHash); 
            }
 
            diskCache.RemoveAllCodegenFiles();
            diskCache.SavePreservedSpecialFilesCombinedHash(specialFilesDateTimeCombiner.CombinedHash);
        }
        else { 
            Debug.Trace("BuildManager", "BuildManager: the special files are up to date");
        } 
 
        Debug.Assert(File.Exists(_webHashFilePath));
 
        // VSWhidbey 537929 : Setup a filechange monitor for the web.hash file. If this file is modified,
        // we will need to shutdown the appdomain so we don't use the obsolete assemblies. The new appdomain
        // will use the up-to-date assemblies.
        HttpRuntime.FileChangesMonitor.StartMonitoringFile(_webHashFilePath, 
            new FileChangeEventHandler(this.OnWebHashFileChange));
    } 
 
    private void OnWebHashFileChange(Object sender, FileChangeEvent e) {
        // Shutdown the app domain 
        Debug.Trace("BuildManager", _webHashFilePath + " changed - shutting down the app domain");
        Debug.Trace("AppDomainFactory", "Shutting down appdomain because " + _webHashFilePath + " file changed");

        HttpRuntime.ShutdownAppDomain(ApplicationShutdownReason.BuildManagerChange, "Change in " + _webHashFilePath); 
    }
 
    /* 
     * Check if an assembly name is reserved for a special purpose
     */ 
    internal static bool IsReservedAssemblyName(string assemblyName) {

        if (String.Compare(assemblyName, CodeDirectoryAssemblyName,
                StringComparison.OrdinalIgnoreCase) == 0 || 
            String.Compare(assemblyName, ResourcesDirectoryAssemblyName,
                StringComparison.OrdinalIgnoreCase) == 0 || 
            String.Compare(assemblyName, WebRefDirectoryAssemblyName, 
                StringComparison.OrdinalIgnoreCase) == 0 ||
            String.Compare(assemblyName, GlobalAsaxAssemblyName, 
                StringComparison.OrdinalIgnoreCase) == 0) {

            return true;
        } 

        return false; 
    } 

    // excludedSubdirectories contains a list of subdirectory names that should not be 
    // recursively included in the compilation (they'll instead be compiled into their
    // own assemblies).
    private Assembly CompileCodeDirectory(VirtualPath virtualDir, CodeDirectoryType dirType,
        string assemblyName, StringSet excludedSubdirectories) { 

        Debug.Trace("BuildManager", "CompileCodeDirectory(" + virtualDir.VirtualPathString + ")"); 
 
        bool isDirectoryAllowed = true;
        if (IsPrecompiledApp) { 
            // Most special dirs are not allowed in precompiled apps.  App_LocalResources is
            // an exception, as it is allowed in updatable precompiled apps.
            if (IsUpdatablePrecompiledAppInternal && dirType == CodeDirectoryType.LocalResources)
                isDirectoryAllowed = true; 
            else
                isDirectoryAllowed = false; 
        } 

        // Remember the referenced assemblies based on the current count. 
        AssemblyReferenceInfo info = new AssemblyReferenceInfo(_topLevelReferencedAssemblies.Count);
        _topLevelAssembliesIndexTable[virtualDir.VirtualPathString] = info;

        Assembly codeAssembly = CodeDirectoryCompiler.GetCodeDirectoryAssembly( 
                virtualDir, dirType, assemblyName, excludedSubdirectories,
                isDirectoryAllowed); 
 
        if (codeAssembly != null) {
 
            // Remember the generated assembly
            info.Assembly = codeAssembly;

            // Page resource assemblies are not added to the top level list 
            if (dirType != CodeDirectoryType.LocalResources) {
                _topLevelReferencedAssemblies.Add(codeAssembly); 
 
                if (dirType == CodeDirectoryType.MainCode || dirType == CodeDirectoryType.SubCode) {
                    if (_codeAssemblies == null) { 
                        _codeAssemblies = new ArrayList();
                    }

                    _codeAssemblies.Add(codeAssembly); 
                }
 
                // Add it to the list of assembly name that we resolve, so that users can 
                // refer to the assemblies by their fixed name (even though they
                // random names).  (VSWhidbey 276776) 
                if (_assemblyResolveMapping == null) {
                    _assemblyResolveMapping = new Hashtable(StringComparer.OrdinalIgnoreCase);
                }
                _assemblyResolveMapping[assemblyName] = codeAssembly; 

                if (dirType == CodeDirectoryType.MainCode) { 
                    // Profile gets built in the same assembly as the main code dir, so 
                    // see whether we can get its type from the assembly.
                    _profileType = ProfileBuildProvider.GetProfileTypeFromAssembly( 
                        codeAssembly, IsPrecompiledApp);

                    // To avoid breaking earlier Whidbey apps, allows the name "__code"
                    // to be used for the main code assembly. 
                    //
                    _assemblyResolveMapping["__code"] = codeAssembly; 
                } 
            }
        } 

        Debug.Trace("BuildManager", "CompileCodeDirectory generated assembly: " +
            (codeAssembly == null ? "None" : codeAssembly.ToString()));
 
        return codeAssembly;
    } 
 

    private void CompileResourcesDirectory() { 

        VirtualPath virtualDir = HttpRuntime.ResourcesDirectoryVirtualPath;

        Debug.Assert(_appResourcesAssembly == null); 
        _appResourcesAssembly = CompileCodeDirectory(virtualDir, CodeDirectoryType.AppResources,
            ResourcesDirectoryAssemblyName, null /*excludedSubdirectories*/); 
    } 

    private void CompileWebRefDirectory() { 

        CompileCodeDirectory(HttpRuntime.WebRefDirectoryVirtualPath, CodeDirectoryType.WebReferences,
            WebRefDirectoryAssemblyName, null /*excludedSubdirectories*/);
    } 

    // Compute the list of subdirectories that should not be compiled with 
    // the top level Code 
    private void EnsureExcludedCodeSubDirectoriesComputed() {
 
        if (_excludedCodeSubdirectories != null)
            return;

        _excludedCodeSubdirectories = new CaseInsensitiveStringSet(); 

        // Get the list of sub directories that will be compiled separately 
        CodeSubDirectoriesCollection codeSubDirectories = CompilationUtil.GetCodeSubDirectories(); 

        // Add them to the exclusion list of the top level code directory 
        if (codeSubDirectories != null) {
            foreach (CodeSubDirectory entry in codeSubDirectories) {
                _excludedCodeSubdirectories.Add(entry.DirectoryName);
            } 
        }
    } 
 
    private void CompileCodeDirectories() {
 
        VirtualPath virtualDir = HttpRuntime.CodeDirectoryVirtualPath;

        // Get the list of sub directories that will be compiled separately
        CodeSubDirectoriesCollection codeSubDirectories = CompilationUtil.GetCodeSubDirectories(); 

        if (codeSubDirectories != null) { 
 
            // Compile all the subdirectory that are listed in config.
 
            foreach (CodeSubDirectory entry in codeSubDirectories) {

                //
 

 
                VirtualPath virtualSubDir = virtualDir.SimpleCombineWithDir(entry.DirectoryName); 

                string assemblyName = SubCodeDirectoryAssemblyNamePrefix + entry.AssemblyName; 

                // Compile the subdirectory tree (no exclusions)
                CompileCodeDirectory(virtualSubDir, CodeDirectoryType.SubCode, assemblyName,
                    null /*excludedSubdirectories*/); 
            }
        } 
 
        EnsureExcludedCodeSubDirectoriesComputed();
 
        // Compile the top level Code directory tree, minus the excluded subdirectories
        CompileCodeDirectory(virtualDir, CodeDirectoryType.MainCode,
            CodeDirectoryAssemblyName, _excludedCodeSubdirectories);
    } 

    private void CompileGlobalAsax() { 
        _globalAsaxBuildResult = ApplicationBuildProvider.GetGlobalAsaxBuildResult(IsPrecompiledApp); 

        // Make sure that global.asax notifications are set up (VSWhidbey 267245) 
        HttpApplicationFactory.SetupFileChangeNotifications();

        if (_globalAsaxBuildResult != null) {
 
            // We need to add not only the global.asax type, but also its parent types to
            // the top level assembly list.  This can happen when global.asax has a 'src' 
            // attribute pointing to a source file containing its base type. 
            Type type = _globalAsaxBuildResult.ResultType;
 
            while (type.Assembly != typeof(HttpRuntime).Assembly) {
                _topLevelReferencedAssemblies.Add(type.Assembly);

                type = type.BaseType; 
            }
        } 
    } 

    // Call the AppInitialize method in the Code assembly if there is one 
    internal static void CallAppInitializeMethod() {

        // Make sure the code directory has been processed
        _theBuildManager.EnsureTopLevelFilesCompiled(); 

        CodeDirectoryCompiler.CallAppInitializeMethod(); 
    } 

    internal void EnsureTopLevelFilesCompiled() { 

        // This should never get executed in non-hosted appdomains
        Debug.Assert(HostingEnvironment.IsHosted);
 
        // If we already tried and got an exception, just rethrow it
        if (_topLevelFileCompilationException != null && !SkipTopLevelCompilationExceptions) { 
            ReportTopLevelCompilationException(); 
        }
 
        if(_topLevelFilesCompiledStarted)
            return;

        // Set impersonation to hosting identity (process or UNC) 
        using (new ApplicationImpersonationContext()) {
            bool gotLock = false; 
            _parseErrorReported = false; 

            try { 
                // Grab the compilation mutex, since this method accesses the codegen files
                CompilationLock.GetLock(ref gotLock);

                // Check again if there is an exception 
                if (_topLevelFileCompilationException != null && !SkipTopLevelCompilationExceptions) {
                    ReportTopLevelCompilationException(); 
                } 

                // Check again if we're done 
                if(_topLevelFilesCompiledStarted)
                    return;

                _topLevelFilesCompiledStarted = true; 
                _topLevelReferencedAssemblies = new List();
                _topLevelAssembliesIndexTable = 
                    new Dictionary(StringComparer.OrdinalIgnoreCase); 

                // 
                _topLevelReferencedAssemblies.Add(typeof(HttpRuntime).Assembly);
                _topLevelReferencedAssemblies.Add(typeof(System.ComponentModel.Component).Assembly);

                _compilationStage = CompilationStage.TopLevelFiles; 

                CompileResourcesDirectory(); 
                CompileWebRefDirectory(); 
                CompileCodeDirectories();
 
                _compilationStage = CompilationStage.GlobalAsax;

                CompileGlobalAsax();
 
                _compilationStage = CompilationStage.BrowserCapabilities;
 
                // Call GetBrowserCapabilitiesType() to make sure browserCap directory is compiled 
                // early on.  This avoids getting into potential deadlock situations later (VSWhidbey 530732).
                // For the same reason, get the EmptyHttpCapabilitiesBase. 
                BrowserCapabilitiesCompiler.GetBrowserCapabilitiesType();
                IFilterResolutionService dummy = HttpCapabilitiesBase.EmptyHttpCapabilitiesBase;

                _compilationStage = CompilationStage.AfterTopLevelFiles; 
            }
            catch (Exception e) { 
                // Remember the exception, and rethrow it 
                _topLevelFileCompilationException = e;
 
                // Do not rethrow the exception since so CBM can still provide partial support
                if (!SkipTopLevelCompilationExceptions) {

                    if (!_parseErrorReported) { 
                        // Report the error if this is not a CompileException. CompileExceptions are handled
                        // directly by the AssemblyBuilder already. 
                        if (!(e is HttpCompileException)) { 
                            ReportTopLevelCompilationException();
                        } 
                    }

                    throw;
                } 
            }
            finally { 
                _topLevelFilesCompiledCompleted = true; 

                // Always release the mutex if we had taken it 
                if (gotLock) {
                    CompilationLock.ReleaseLock();
                }
            } 
        }
    } 
 
    // Generate a random file name with 8 characters
    private static string GenerateRandomFileName() { 
        // Generate random bytes
        byte[] data = new byte[6];

        lock (_rng) { 
            _rng.GetBytes(data);
        } 
 
        // Turn them into a string containing only characters valid in file names/url
        string s = Convert.ToBase64String(data).ToLower(CultureInfo.InvariantCulture); 
        s = s.Replace('/', '-');
        s = s.Replace('+', '_');

        return s; 
    }
 
    internal static string GenerateRandomAssemblyName(string baseName) { 
        return GenerateRandomAssemblyName(baseName, true /*topLevel*/);
    } 

    // Generate a random name for an assembly, starting with the passed in prefix
    internal static string GenerateRandomAssemblyName(string baseName, bool topLevel) {
 
        // Start with the passed in base name
        string assemblyName = baseName; 
 
        // Append a random token to it.
 
        // However, don't do this when precompiling for deployment since, we want the name to be more predictable (DevDiv 36625)
        if (PrecompilingForDeployment)
            return baseName;
 
        // Also, don't use random names for top level files in OptimizeCompilations mode so that pages
        // can more easily bind against rebuilt top level assemblies 
        if (OptimizeCompilations && topLevel) 
            return baseName;
 
        return baseName += "." + GenerateRandomFileName();
    }

    private static string GetGeneratedAssemblyBaseName(VirtualPath virtualPath) { 

        // Name the assembly using the same scheme as cache keys 
        return GetCacheKeyFromVirtualPath(virtualPath); 
    }
 
    /*
     * Look for a type by name in the top level and config assemblies
     */
    public static Type GetType(string typeName, bool throwOnError) { 
        return GetType(typeName, throwOnError, false);
    } 
 
    /*
     * Look for a type by name in the top level and config assemblies 
     */
    public static Type GetType(string typeName, bool throwOnError, bool ignoreCase) {
        // If it contains an assembly name, just call Type.GetType().  Do this before even trying
        // to initialize the BuildManager, so that if InitializeBuildManager has errors, it doesn't 
        // affect us when the type string can be resolved via Type.GetType().
        Type type = null; 
        if (Util.TypeNameContainsAssembly(typeName)) { 
            type = Type.GetType(typeName, throwOnError, ignoreCase);
 
            if (type != null) {
                    return type;
            }
        } 

        // Make sure the build manager is initialized.  If it fails to initialize for any reason, 
        // don't attempt to use the fancy GetType logic.  Just call Type.GetType instead (VSWhidbey 284498) 
        if (!InitializeBuildManager()) {
            return Type.GetType(typeName, throwOnError, ignoreCase); 
        }

        // First, always try System.Web.dll
        try { 
            type = typeof(BuildManager).Assembly.GetType(typeName,
                false /*throwOnError*/, ignoreCase); 
        } 
        catch (ArgumentException e) {
            // Even though we pass false to throwOnError, GetType can throw if the 
            // assembly name is malformed.  In that case, throw our own error instead
            // of the cryptic ArgumentException (VSWhidbey 275586)
            throw new HttpException(
                SR.GetString(SR.Invalid_type, typeName), e); 
        }
 
        if (type != null) return type; 

        _theBuildManager.EnsureTopLevelFilesCompiled(); 

        // Otherwise, look for the type in the top level assemblies
        type = Util.GetTypeFromAssemblies(TheBuildManager.TopLevelReferencedAssemblies,
            typeName, ignoreCase); 
        if (type != null) return type;
 
        // Otherwise, look for the type in the config assemblies 
        AssemblyCollection configAssemblies = CompilationUtil.GetAssembliesForAppLevel();
        if (configAssemblies != null) { 
            Type t = CompilationUtil.GetTypeFromAssemblies(configAssemblies, typeName, ignoreCase);
            if (t != null) {
                // If we had already found a different one, it's an ambiguous type reference
                if (type != null && t != type) { 
                    throw new HttpException(SR.GetString(
                        SR.Ambiguous_type, typeName, Util.GetAssemblySafePathFromType(type), 
                        Util.GetAssemblySafePathFromType(t))); 
                }
 
                type = t;
            }
        }
 
        if (type == null && throwOnError) {
            throw new HttpException( 
                SR.GetString(SR.Invalid_type, typeName)); 
        }
 
        return type;
    }

    /* 
     * Gets a type from one of the code assemblies
     */ 
    internal static Type GetTypeFromCodeAssembly(string typeName, bool ignoreCase) { 

        // No code assembly: return 
        if (CodeAssemblies == null)
            return null;

        return Util.GetTypeFromAssemblies(CodeAssemblies, typeName, ignoreCase); 
    }
 
    internal static BuildProvider CreateBuildProvider(VirtualPath virtualPath, 
        CompilationSection compConfig, ICollection referencedAssemblies,
        bool failIfUnknown) { 

        return CreateBuildProvider(virtualPath, BuildProviderAppliesTo.Web,
            compConfig, referencedAssemblies, failIfUnknown);
    } 

    internal static BuildProvider CreateBuildProvider(VirtualPath virtualPath, 
        BuildProviderAppliesTo neededFor, 
        CompilationSection compConfig, ICollection referencedAssemblies,
        bool failIfUnknown) { 

        string extension = virtualPath.Extension;

        Type buildProviderType = CompilationUtil.GetBuildProviderTypeFromExtension(compConfig, 
            extension, neededFor, failIfUnknown);
        if (buildProviderType == null) 
            return null; 

        object o = HttpRuntime.CreatePublicInstance(buildProviderType); 

        BuildProvider buildProvider = (BuildProvider) o;

        buildProvider.SetVirtualPath(virtualPath); 
        buildProvider.SetReferencedAssemblies(referencedAssemblies);
 
        return buildProvider; 
    }
 
    internal static void ValidateCodeFileVirtualPath(VirtualPath virtualPath) {
        _theBuildManager.ValidateVirtualPathInternal(virtualPath, false /*allowCrossApp*/, true /*codeFile*/);
    }
 
    private void ValidateVirtualPathInternal(VirtualPath virtualPath, bool allowCrossApp, bool codeFile) {
 
        if (!allowCrossApp) { 
            virtualPath.FailIfNotWithinAppRoot();
        } 
        else {
            // If cross app is allowed, and the path is in a different app, nothing more to check
            if (!virtualPath.IsWithinAppRoot)
                return; 
        }
 
        // 
        // Now, detect if it's under a special directory (e.g. 'code', 'resources', 'themes')
        // 

        // If it's exactly the app root, it's fine
        if (HttpRuntime.AppDomainAppVirtualPathObject == virtualPath)
            return; 

        int appPathLen = HttpRuntime.AppDomainAppVirtualPathString.Length; 
 
        string virtualPathString = virtualPath.VirtualPathString;
 
        // This could happen if the vpath is "/app" (while the app vpath is "/app/")
        if (virtualPathString.Length < appPathLen)
            return;
 
        // If no slash after the approot (e.g. "/app/foo.aspx"), it's valid
        int slashIndex = virtualPathString.IndexOf('/', appPathLen); 
        if (slashIndex < 0) 
            return;
 
        // Get the name of the first directory under the app root (e.g. "/app/aaa/bbb/foo.aspx" -> "aaa")
        string dir = virtualPathString.Substring(appPathLen, slashIndex - appPathLen);

        // If it's a forbidden directory, fail 
        if (_forbiddenTopLevelDirectories.Contains(dir)) {
            throw new HttpException(SR.GetString( 
                SR.Illegal_special_dir, virtualPathString, dir)); 
        }
    } 

    /*
     * Returns a single hash code that represents the state of the built object for
     * the passed in virtualPath.  If it isn't already built, don't build it, but just 
     * return 0.  This can be used to determine the validity of output cache that
     * has been persisted to disk. 
     */ 
    internal static long GetBuildResultHashCodeIfCached(
        HttpContext context, string virtualPath) { 

        BuildResult result = GetVPathBuildResult(context, VirtualPath.Create(virtualPath),
            true /*noBuild*/, false /*allowCrossApp*/);
 
        // If it's not cached, return 0
        if (result == null) 
            return 0; 

        // Return a single hash code based on both of the BuildResult's hash codes 
        string dependenciesHash = result.VirtualPathDependenciesHash;
        Debug.Assert(result.DependenciesHashComputed);
        return result.ComputeHashCode(s_topLevelHash, StringUtil.GetStringHashCode(dependenciesHash));
    } 

    internal static BuildResult GetVPathBuildResult(VirtualPath virtualPath) { 
 
        return GetVPathBuildResult(null /*context*/, virtualPath,
            false /*noBuild*/, false /*allowCrossApp*/, false /*allowBuiltInPrecompile*/); 
    }

    internal static BuildResult GetVPathBuildResult(HttpContext context, VirtualPath virtualPath) {
 
        return GetVPathBuildResult(context, virtualPath, false /*noBuild*/, false /*allowCrossApp*/, false /*allowBuiltInPrecompile*/);
    } 
 
    internal static BuildResult GetVPathBuildResult(HttpContext context, VirtualPath virtualPath,
        bool noBuild, bool allowCrossApp) { 

        return GetVPathBuildResult(context, virtualPath, noBuild, allowCrossApp, false /*allowBuiltInPrecompile*/);
    }
 
    /*
     * Calls either GetVPathBuildResultWithNoAssert or GetVPathBuildResultWithAssert, 
     * depending on whether there is any point in asserting. 
     */
    internal static BuildResult GetVPathBuildResult(HttpContext context, VirtualPath virtualPath, 
        bool noBuild, bool allowCrossApp, bool allowBuildInPrecompile) {

        // Could be called with user code on the stack, so need to assert here (VSWhidbey 85026)
        // e.g. This can happen during a Server.Transfer, or a LoadControl. 
        // But if we're running in full trust, skip the assert for perf reasons (VSWhidbey 146871)
        if (HttpRuntime.IsFullTrust) { 
            return GetVPathBuildResultWithNoAssert(context, virtualPath, noBuild, allowCrossApp, allowBuildInPrecompile); 
        }
        else { 
            return GetVPathBuildResultWithAssert(context, virtualPath, noBuild, allowCrossApp, allowBuildInPrecompile);
        }
    }
 
    /*
     * Same as GetVPathBuildResultWithNoAssert, but with an Unrestricted Assert. 
     */ 
    [PermissionSet(SecurityAction.Assert, Unrestricted=true)]
    internal static BuildResult GetVPathBuildResultWithAssert( 
        HttpContext context, VirtualPath virtualPath, bool noBuild, bool allowCrossApp, bool allowBuildInPrecompile) {

        return GetVPathBuildResultWithNoAssert(context, virtualPath, noBuild, allowCrossApp, allowBuildInPrecompile);
    } 

    internal static BuildResult GetVPathBuildResultWithNoAssert( 
        HttpContext context, VirtualPath virtualPath, bool noBuild, bool allowCrossApp, bool allowBuildInPrecompile) { 

        using (new ApplicationImpersonationContext()) { 
            return _theBuildManager.GetVPathBuildResultInternal(virtualPath, noBuild, allowCrossApp, allowBuildInPrecompile);
        }
    }
 
    // name of the slot in call context
    private const String CircularReferenceCheckerSlotName = "CircRefChk"; 
 
    private BuildResult GetVPathBuildResultInternal(VirtualPath virtualPath, bool noBuild, bool allowCrossApp, bool allowBuildInPrecompile) {
 
        Debug.Trace("BuildManager", "GetBuildResult(" + virtualPath + ")");

        // This should never be called while building top level files (VSWhidbey 480256)
        if (_compilationStage == CompilationStage.TopLevelFiles) { 
            throw new HttpException(SR.GetString(SR.Too_early_for_webfile, virtualPath));
        } 
 
        // Make sure the path is not relative
        Debug.Assert(!virtualPath.IsRelative); 

        // Try the cache first before getting the mutex
        BuildResult result = GetVPathBuildResultFromCacheInternal(virtualPath);
        if (result != null) 
            return result;
 
        // If we were only checking the cache and it wasn't there, return null. 
        if (noBuild)
            return null; 

        // Check if it's trying to go cross app, or points to a special directory.
        // It's important to do this before checkin existence, to avoid revealing information
        // about other apps (VSWhidbey 442632) 
        ValidateVirtualPathInternal(virtualPath, allowCrossApp, false /*codeFile*/);
 
        // Before grabbing the lock, make sure the file at least exists (ASURT 46465) 
        Util.CheckVirtualFileExists(virtualPath);
 
        // If this is a precompiled app, complain if we couldn't find it in the cache
        if (IsNonUpdatablePrecompiledApp && !allowBuildInPrecompile) {
            throw new HttpException(
                SR.GetString(SR.Cant_update_precompiled_app, virtualPath)); 
        }
 
        bool gotLock = false; 

        try { 
            // Grab the compilation mutex
            CompilationLock.GetLock(ref gotLock);

            // Check the cache a second time after getting the mutex 
            result = GetVPathBuildResultFromCacheInternal(virtualPath);
            if (result != null) 
                return result; 

            // Get the circular reference checker (create it if needed) 
            VirtualPathSet circularReferenceChecker;
            circularReferenceChecker = CallContext.GetData(CircularReferenceCheckerSlotName)
                as VirtualPathSet;
            if (circularReferenceChecker == null) { 
                circularReferenceChecker = new VirtualPathSet();
 
                // Create it and save it in the CallContext 
                CallContext.SetData(CircularReferenceCheckerSlotName, circularReferenceChecker);
            } 

            // If a circular reference is detected, throw an error
            if (circularReferenceChecker.Contains(virtualPath)) {
                throw new HttpException( 
                    SR.GetString(SR.Circular_include));
            } 
 
            // Add the current virtualPath to the circular reference checker
            circularReferenceChecker.Add(virtualPath); 

            try {
                //
                EnsureTopLevelFilesCompiled(); 
                result = CompileWebFile(virtualPath);
            } 
            finally { 
                // Remove the current virtualPath from the circular reference checker
                Debug.Assert(circularReferenceChecker.Contains(virtualPath)); 
                circularReferenceChecker.Remove(virtualPath);
            }
        }
        finally { 
            // Always release the mutex if we had taken it
            if (gotLock) { 
                CompilationLock.ReleaseLock(); 
            }
        } 

        return result;
    }
 
    private BuildResult CompileWebFile(VirtualPath virtualPath) {
 
        BuildResult result = null; 

        if (_topLevelFilesCompiledCompleted) { 

            VirtualPath parentPath = virtualPath.Parent;

            // First, try to batch the directory if enabled 
            if (IsBatchEnabledForDirectory(parentPath)) {
                BatchCompileWebDirectory(null, parentPath, true /*ignoreErrors*/); 
 
                // If successful, it would have been cached to memory
                string cacheKey = GetCacheKeyFromVirtualPath(virtualPath); 
                result = _memoryCache.GetBuildResult(cacheKey);

                if (result != null) {
                    // If what we found in the cache is a CompileError, rethrow the exception 
                    if (result is BuildResultCompileError) {
                        throw ((BuildResultCompileError)result).CompileException; 
                    } 

                    return result; 
                }
            }
        }
 

        DateTime utcStart = DateTime.UtcNow; 
 
        // Name the assembly based on the virtual path, in order to get a recognizable name
        string outputAssemblyName = BuildManager.WebAssemblyNamePrefix + 
            BuildManager.GenerateRandomAssemblyName(
            GetGeneratedAssemblyBaseName(virtualPath), false /*topLevel*/);

        BuildProvidersCompiler bpc = new BuildProvidersCompiler(virtualPath /*configPath*/, outputAssemblyName); 

        // Create a BuildProvider based on the virtual path 
        BuildProvider buildProvider = CreateBuildProvider(virtualPath, bpc.CompConfig, 
            bpc.ReferencedAssemblies, true /*failIfUnknown*/);
 
        // Set the BuildProvider using a single item collection
        bpc.SetBuildProviders(new SingleObjectCollection(buildProvider));

        // Compile it 
        CompilerResults results;
 
        try { 
            results = bpc.PerformBuild();
            result = buildProvider.GetBuildResult(results); 
        }
        catch (HttpCompileException e) {

            // If we're not supposed to cache the exception, just rethrow it 
            if (e.DontCache)
                throw; 
 
            result = new BuildResultCompileError(virtualPath, e);
 
            // Add the dependencies to the compile error build provider, so that
            // we will retry compilation when a dependency changes
            buildProvider.SetBuildResultDependencies(result);
 
            // Remember the virtualpath dependencies, so that we will correctly
            // invalidate buildresult when depdency changes. 
            e.VirtualPathDependencies = buildProvider.VirtualPathDependencies; 

            // Cache it for next time 
            CacheVPathBuildResultInternal(virtualPath, result, utcStart);

            // Set the DontCache flag, so that the exception will not be incorrectly
            // cached again lower down the stack (VSWhidbey 128234) 
            e.DontCache = true;
 
            throw; 
        }
 
        if (result == null)
            return null;

        // Cache it for next time 
        CacheVPathBuildResultInternal(virtualPath, result, utcStart);
 
        return result; 
    }
 
    // Hashtbale to remember the local resources assembly for each directory (or null
    // if there isn't one). Hashtable
    private Hashtable _localResourcesAssemblies = new Hashtable();
 
    private void EnsureFirstTimeDirectoryInit(VirtualPath virtualDir) {
 
        // Don't process local resources when precompiling for updatable deployment. 
        // Instead, we deploy the App_LocalResources folder as is.
        if (PrecompilingForUpdatableDeployment) 
            return;

        if (virtualDir == null)
            return; 

        // Only do this once per directory 
        if (_localResourcesAssemblies.Contains(virtualDir)) 
            return;
 
        // Don't do anything if it's outside the app root
        if (!virtualDir.IsWithinAppRoot)
            return;
 
        Debug.Trace("BuildManager", "EnsureFirstTimeDirectoryInit(" + virtualDir + ")");
 
        // Get the virtual path to the LocalResources subdirectory for this directory 
        VirtualPath localResDir = virtualDir.SimpleCombineWithDir(HttpRuntime.LocalResourcesDirectoryName);
 
        bool dirExists;
        try {
            dirExists = localResDir.DirectoryExists();
        } 
        catch {
            // If an exception happens, the directory may be outside the application, 
            // in which case we should skip this logic, and act is if there are no 
            // local resources (VSWhidbey 258776);
 
            _localResourcesAssemblies[virtualDir] = null;
            return;
        }
 
        Debug.Trace("BuildManager", "EnsureFirstTimeDirectoryInit: dirExists=" + dirExists);
 
        try { 
            // Monitor changes to it so the appdomain can shut down when it changes
            HttpRuntime.StartListeningToLocalResourcesDirectory(localResDir); 
        }
        catch {
            // could fail for long directory names
            if (dirExists) { 
                throw;
            } 
        } 

        Assembly resourceAssembly = null; 

        // If it exists, build it
        if (dirExists) {
 
            string localResAssemblyName = GetLocalResourcesAssemblyName(virtualDir);
 
            bool gotLock = false; 

            try { 
                // Grab the compilation mutex, since this method accesses the codegen files
                CompilationLock.GetLock(ref gotLock);

                resourceAssembly = CompileCodeDirectory(localResDir, CodeDirectoryType.LocalResources, 
                    localResAssemblyName, null /*excludedSubdirectories*/);
            } 
            finally { 
                // Always release the mutex if we had taken it
                if (gotLock) { 
                    CompilationLock.ReleaseLock();
                }
            }
        } 

        // Cache it whether it's null or not 
        _localResourcesAssemblies[virtualDir] = resourceAssembly; 
    }
 
    // VSWhidbey Bug 560521
    private void EnsureFirstTimeDirectoryInitForDependencies(ICollection dependencies) {
        foreach (String dependency in dependencies) {
            VirtualPath dependencyPath = VirtualPath.Create(dependency); 
            VirtualPath dir = dependencyPath.Parent;
            EnsureFirstTimeDirectoryInit(dir); 
        } 
    }
 

    // Retrieve a cached local resources assembly (could be null)
    internal static Assembly GetLocalResourcesAssembly(VirtualPath virtualDir) {
        return (Assembly) _theBuildManager._localResourcesAssemblies[virtualDir]; 
    }
 
    internal static string GetLocalResourcesAssemblyName(VirtualPath virtualDir) { 
        return LocalResourcesDirectoryAssemblyName + "." + GetGeneratedAssemblyBaseName(virtualDir);
    } 

    // name of the slot in call context
    private const String BatchCompilationSlotName = "BatchCompileChk";
 
    // Check if batching is enabled for directory specified by virtualDir
    private bool IsBatchEnabledForDirectory(VirtualPath virtualDir) { 
        // False if compile for fixed name 
        if (CompileWithFixedAssemblyNames) {
            return false; 
        }

        // Always enable batching for deployement
        if (PrecompilingForDeployment) { 
            return true;
        } 
 
        // If it's called by other non-precompile CBM methods, always disable batching
        if (BuildManagerHost.InClientBuildManager && !PerformingPrecompilation) { 
            return false;
        }

        // Check the config 
        return CompilationUtil.IsBatchingEnabled(virtualDir.VirtualPathString);
    } 
 
    private bool BatchCompileWebDirectory(VirtualDirectory vdir, VirtualPath virtualDir, bool ignoreErrors) {
 
        // Exactly one of vdir and virtualDir should be non-null.  The idea is to avoid calling
        // VirtualPathProvider.GetDirectory if batching is disabled (VSWhidbey 437549).

        if (virtualDir == null) 
            virtualDir = vdir.VirtualPathObject;
 
        if (vdir == null) 
            vdir = HostingEnvironment.VirtualPathProvider.GetDirectory(virtualDir);
 
        // Then, check if we're already tried batch compiling this directory on this same request

        CaseInsensitiveStringSet directoryBatchCompilerChecker;
        directoryBatchCompilerChecker = CallContext.GetData(BatchCompilationSlotName) 
            as CaseInsensitiveStringSet;
 
        if (directoryBatchCompilerChecker == null) { 
            directoryBatchCompilerChecker = new CaseInsensitiveStringSet();
 
            // Create it and save it in the CallContext
            CallContext.SetData(BatchCompilationSlotName, directoryBatchCompilerChecker);
        }
 
        // If we've already tried batch compiling this directory, don't do anything
        if (directoryBatchCompilerChecker.Contains(vdir.VirtualPath)) 
            return false; 

        // Add the current virtualDir to the batch compiler checker 
        directoryBatchCompilerChecker.Add(vdir.VirtualPath);

        // If we're in the process of precompiling an app, never ignore errors.
        if (_precompilingApp) 
            ignoreErrors = false;
 
        return BatchCompileWebDirectoryInternal(vdir, ignoreErrors); 
    }
 
    private bool BatchCompileWebDirectoryInternal(VirtualDirectory vdir, bool ignoreErrors) {

        WebDirectoryBatchCompiler sdc = new WebDirectoryBatchCompiler(vdir);
 
        // Just ignore build providers that have errors
        if (ignoreErrors) { 
            sdc.SetIgnoreErrors(); 

            // Don't propagate errors that happen during batch compilation 
            try {
                sdc.Process();
            }
            catch { 
                return false;
            } 
        } 
        else {
            sdc.Process(); 
        }

        return true;
    } 

    internal static Type GetGlobalAsaxType() { 
        return _theBuildManager.GetGlobalAsaxTypeInternal(); 
    }
 
    private Type GetGlobalAsaxTypeInternal() {
        EnsureTopLevelFilesCompiled();

        if (_globalAsaxBuildResult == null) 
            return typeof(HttpApplication);
 
        return _globalAsaxBuildResult.ResultType; 
    }
 
    internal static BuildResultCompiledGlobalAsaxType GetGlobalAsaxBuildResult() {
        return _theBuildManager.GetGlobalAsaxBuildResultInternal();
    }
 
    private BuildResultCompiledGlobalAsaxType GetGlobalAsaxBuildResultInternal() {
        EnsureTopLevelFilesCompiled(); 
 
        return _globalAsaxBuildResult;
    } 

    internal string[] GetCodeDirectories() {

        VirtualPath virtualDir = HttpRuntime.CodeDirectoryVirtualPath; 

        // If there is no Code directory, return an empty array 
        if (!virtualDir.DirectoryExists()) 
            return new string[0];
 
        // Get the list of code sub directories that will be compiled separately
        CodeSubDirectoriesCollection codeSubDirectories = CompilationUtil.GetCodeSubDirectories();

        // Compute the number of code dirs, including the root one 
        int numOfCodeDirs = 1;
        if (codeSubDirectories != null) 
            numOfCodeDirs += codeSubDirectories.Count; 

        string[] codeDirs = new string[numOfCodeDirs]; 
        int current = 0;

        if (codeSubDirectories != null) {
            foreach (CodeSubDirectory entry in codeSubDirectories) { 

                VirtualPath virtualSubDir = virtualDir.SimpleCombineWithDir(entry.DirectoryName); 
                codeDirs[current++] = virtualSubDir.VirtualPathString; 
            }
        } 

        // Add the root code dir at the end of the list (since it's compiled last)
        codeDirs[current++] = virtualDir.VirtualPathString;
 
        return codeDirs;
    } 
 
    internal void GetCodeDirectoryInformation(VirtualPath virtualCodeDir,
        out Type codeDomProviderType, out CompilerParameters compilerParameters, 
        out string generatedFilesDir) {

        // Backup the compilation stage, since the call will modify it
        CompilationStage savedCompilationStage = _compilationStage; 

        try { 
            GetCodeDirectoryInformationInternal(virtualCodeDir, out codeDomProviderType, 
                out compilerParameters, out generatedFilesDir);
        } 
        finally {
            // Restore the compilation stage
            _compilationStage = savedCompilationStage;
        } 
    }
 
    private void GetCodeDirectoryInformationInternal(VirtualPath virtualCodeDir, 
        out Type codeDomProviderType, out CompilerParameters compilerParameters,
        out string generatedFilesDir) { 

        StringSet excludedSubdirectories = null;

        CodeDirectoryType dirType; 

        // Get the DirectoryType based on the path 
        if (virtualCodeDir == HttpRuntime.CodeDirectoryVirtualPath) { 

            // If it's the top level code directory, make sure we exclude any 
            // subdirectories that are compiled separately
            EnsureExcludedCodeSubDirectoriesComputed();

            excludedSubdirectories = _excludedCodeSubdirectories; 

            dirType = CodeDirectoryType.MainCode; 
 
            _compilationStage = CompilationStage.TopLevelFiles;
        } 
        else if (virtualCodeDir == HttpRuntime.ResourcesDirectoryVirtualPath) {

            dirType = CodeDirectoryType.AppResources;
 
            _compilationStage = CompilationStage.TopLevelFiles;
        } 
        // If virtualCodeDir is a subdir of WebReference virtual path. 
        else if (String.Compare(virtualCodeDir.VirtualPathString, 0,
            HttpRuntime.WebRefDirectoryVirtualPath.VirtualPathString, 0, HttpRuntime.WebRefDirectoryVirtualPath.VirtualPathString.Length, 
            StringComparison.OrdinalIgnoreCase) == 0) {

            // Use the top WebReference directory info for its sub directories.
            virtualCodeDir = HttpRuntime.WebRefDirectoryVirtualPath; 
            dirType = CodeDirectoryType.WebReferences;
 
            _compilationStage = CompilationStage.TopLevelFiles; 
        }
        else if (String.Compare(virtualCodeDir.FileName, HttpRuntime.LocalResourcesDirectoryName, 
            StringComparison.OrdinalIgnoreCase) == 0) {

            dirType = CodeDirectoryType.LocalResources;
 
            // LocalResources are compiled *after* top level files
            _compilationStage = CompilationStage.AfterTopLevelFiles; 
        } 
        else {
            // If all else fails, treat it as a sub directory 
            //
            dirType = CodeDirectoryType.SubCode;

            // Sub-code dirs are compiled *before* the main code dir 
            _compilationStage = CompilationStage.TopLevelFiles;
        } 
 
        Debug.Assert(virtualCodeDir.HasTrailingSlash);
        AssemblyReferenceInfo info = TheBuildManager.TopLevelAssembliesIndexTable[virtualCodeDir.VirtualPathString]; 
        if (info == null) {
            throw new InvalidOperationException(
                SR.GetString(SR.Invalid_CodeSubDirectory_Not_Exist, virtualCodeDir));
        } 

        // Get the info we need for this code directory 
        CodeDirectoryCompiler.GetCodeDirectoryInformation( 
            virtualCodeDir, dirType, excludedSubdirectories, info.ReferenceIndex,
            out codeDomProviderType, out compilerParameters, 
            out generatedFilesDir);

        Assembly resultAssembly = info.Assembly;
 
        if (resultAssembly != null) {
            // Use the runtime generated assembly location. VSWhidbey 400335 
            compilerParameters.OutputAssembly = resultAssembly.Location; 
        }
    } 

    internal static Type GetProfileType() {
        return _theBuildManager.GetProfileTypeInternal();
    } 

    private Type GetProfileTypeInternal() { 
        EnsureTopLevelFilesCompiled(); 
        return _profileType;
    } 


    //
    // Caching related code 
    //
 
 
    public static ICollection GetVirtualPathDependencies(string virtualPath) {
 
        CompilationSection compConfig = RuntimeConfig.GetRootWebConfig().Compilation;

        // Create a BuildProvider based on the virtual path
        BuildProvider buildProvider = CreateBuildProvider(VirtualPath.Create(virtualPath), compConfig, 
            null, false /*failIfUnknown*/);
 
        if (buildProvider == null) 
            return null;
 
        // Get its dependencies
        //
        return buildProvider.GetBuildResultVirtualPathDependencies();
    } 

#if OLD 
    /* 
     * Rewrite the virtualPath if appropriate, in order to support ghosting
     */ 
    private static void GetGhostedVirtualPath(ref string virtualPath) {

        VirtualPathProvider virtualPathProvider = HostingEnvironment.VirtualPathProvider;
 
        string ghostedVirtualPath = virtualPathProvider.GetGhostedVirtualPath(virtualPath);
 
        // If the file is not ghosted, don't change the path 
        if (ghostedVirtualPath == null)
            return; 

        //

 
        // Get the list of virtual paths that it depends on (e.g. user controls)
        ICollection virtualPathDependencies = GetVirtualPathDependencies(virtualPath); 
 
        // If there aren't any, return the ghosted path
        if (virtualPathDependencies == null) { 
            virtualPath = ghostedVirtualPath;
            return;
        }
 
        // Go through all the dependencies, and if we find any that is *not* ghosted
        // (i.e. for which GetGhostedVirtualPath returns null), we treat the whole request 
        // as unghosted (and hence we return without modifying the virtualPath). 

        foreach (string virtualDependency in virtualPathDependencies) { 
            string ghostedVirtualDependencyPath = virtualPathProvider.GetGhostedVirtualPath(
                virtualDependency);
            if (ghostedVirtualDependencyPath == null)
                return; 
        }
 
        // All the dependencies are ghosted, so we can safely use the ghosted path, 
        // which can then be shared for all fully ghosted requests.
        virtualPath = ghostedVirtualPath; 
    }
#endif

    internal static string GetCacheKeyFromVirtualPath(VirtualPath virtualPath) { 
        bool keyFromVPP;
        return GetCacheKeyFromVirtualPath(virtualPath, out keyFromVPP); 
    } 

    /* 
     * Same as GetCacheKeyFromVirtualPathInternal, but caches the cache keys
     * for performance, since creating them is expensive (VSWhidbey 146540)
     */
    static SimpleRecyclingCache _keyCache = new SimpleRecyclingCache(); 
    private static string GetCacheKeyFromVirtualPath(VirtualPath virtualPath, out bool keyFromVPP) {
 
        // Check if the VirtualPathProvider needs to use a non-default cache key 
        string key = virtualPath.GetCacheKey();
 
        // If so, just return it
        if (key != null) {
            keyFromVPP = true;
            return key.ToLowerInvariant(); 
        }
 
        // The VPP didn't return a key, so use our standard key algorithm 
        keyFromVPP = false;
 
        // Check if the key for this virtual path is already cached
        key = _keyCache[virtualPath.VirtualPathString] as string;
        if (key != null) return key;
 
        // Compute the key
        key = GetCacheKeyFromVirtualPathInternal(virtualPath); 
 
        // The key should always be lower case
        Debug.Assert(key == key.ToLowerInvariant()); 

        // Cache it for next time
        _keyCache[virtualPath.VirtualPathString] = key;
 
        return key;
    } 
 
    /*
     * Generate a unique cache key from a virtual path.  e.g. for "/approot/sub1/sub2/foo.aspx" 
     * the key could be "foo.aspx.ccdf220e", where ccdf220e is a hash code from
     * the dir "sub1/sub2".
     */
    private static string GetCacheKeyFromVirtualPathInternal(VirtualPath virtualPath) { 

        // We want the key to be app independent (for precompilation), so we 
        // change the virtual path to be app relative 

        /* Disable assertion since global theme needs to compile theme files in different vroot. 
        Debug.Assert(StringUtil.VirtualPathStartsWithAppPath(virtualPath),
            String.Format("VPath {0} is outside the application: {1}", virtualPath, HttpRuntime.AppDomainAppVirtualPath));
        */
        string virtualPathString = virtualPath.AppRelativeVirtualPathString.ToLowerInvariant(); 
        virtualPathString = UrlPath.RemoveSlashFromPathIfNeeded(virtualPathString);
 
        // Split the path into the directory and the name 
        int slashIndex = virtualPathString.LastIndexOf('/');
        Debug.Assert(slashIndex >= 0 || virtualPathString == "~"); 

        if (virtualPathString == "~")
            return "root";
 
        Debug.Assert(slashIndex != virtualPathString.Length - 1);
        string name = virtualPathString.Substring(slashIndex + 1); 
        string dir; 
        if (slashIndex <= 0)
            dir = "/"; 
        else {
            dir = virtualPathString.Substring(0, slashIndex);
        }
 
        return name + "." + StringUtil.GetStringHashCode(dir).ToString("x", CultureInfo.InvariantCulture);
    } 
 
    internal static BuildResult GetVPathBuildResultFromCache(VirtualPath virtualPath) {
 
        return TheBuildManager.GetVPathBuildResultFromCacheInternal(virtualPath);
    }

    private BuildResult GetVPathBuildResultFromCacheInternal(VirtualPath virtualPath) { 

        bool keyFromVPP; 
        string cacheKey = GetCacheKeyFromVirtualPath(virtualPath, out keyFromVPP); 
        return GetBuildResultFromCacheInternal(cacheKey, keyFromVPP, virtualPath, 0 /*hashCode*/);
    } 

    internal static BuildResult GetBuildResultFromCache(string cacheKey) {
        return _theBuildManager.GetBuildResultFromCacheInternal(cacheKey, false /*keyFromVPP*/, null /*virtualPath*/,
            0 /*hashCode*/); 
    }
 
    internal static BuildResult GetBuildResultFromCache(string cacheKey, VirtualPath virtualPath) { 
        return _theBuildManager.GetBuildResultFromCacheInternal(cacheKey, false /*keyFromVPP*/, virtualPath,
            0 /*hashCode*/); 
    }

    private BuildResult GetBuildResultFromCacheInternal(string cacheKey, bool keyFromVPP,
        VirtualPath virtualPath, long hashCode) { 

        BuildResult result = null; 
 
        // Allow the possibility that BuildManager was not initialized due to
        // a very early failure (e.g. see VSWhidbey 137366) 
        //Debug.Trace("BuildManager", "GetBuildResultFromCacheInternal " + _theBuildManagerInitialized);
        if (!_theBuildManagerInitialized)
            return null;
 
        // The first cache should always be memory
        Debug.Assert(_caches[0] == _memoryCache); 
 
        // Try to get it from the memeory cache before taking any locks (for perf reasons)
        result = _memoryCache.GetBuildResult(cacheKey, virtualPath, hashCode); 
        if (result != null) {
            return PostProcessFoundBuildResult(result, keyFromVPP, virtualPath);
        }
 
        Debug.Trace("BuildManager", "Didn't find '" + virtualPath + "' in memory cache before lock");
 
        lock (this) { 
            // Try to get the BuildResult from the cheapest to most expensive cache
            int i; 
            for (i = 0; i < _caches.Length; i++) {
                result = _caches[i].GetBuildResult(cacheKey, virtualPath, hashCode);

                // There might be changes in local resources for dependencies, 
                // so we need to make sure EnsureFirstTimeDirectoryInit gets called
                // for them even when we already have a cache result. 
                // VSWhidbey Bug 560521 

                if (result != null) { 
                    if (result.VirtualPathDependencies != null) {
                        EnsureFirstTimeDirectoryInitForDependencies(result.VirtualPathDependencies);
                    }
 
                    break;
                } 
 
                // If we didn't find it in the memory cache, perform the per directory
                // initialization.  This is a good place to do this, because we don't 
                // affect the memory cache code path, but we do the init as soon as
                // something is not found in the memory cache.
                if (i == 0 && virtualPath != null) {
                    VirtualPath virtualDir = virtualPath.Parent; 
                    EnsureFirstTimeDirectoryInit(virtualDir);
                } 
            } 

 
            if (result == null)
                return null;

            result = PostProcessFoundBuildResult(result, keyFromVPP, virtualPath); 
            if (result == null)
                return null; 
 
            Debug.Assert(_memoryCache != null);
 
            // If we found it in a cache, cache it in all the caches that come before
            // the one where we found it.  If we found it in the memory cache, this is a no op.
            for (int j = 0; j < i; j++)
                _caches[j].CacheBuildResult(cacheKey, result, DateTime.UtcNow); 

            Debug.Trace("BuildManager", "Found '" + virtualPath + "' in " + _caches[i]); 
 
            return result;
        } 
    }

    private BuildResult PostProcessFoundBuildResult(BuildResult result, bool keyFromVPP, VirtualPath virtualPath) {
 
        // Check that the virtual path in the result matches the passed in
        // virtualPath (VSWhidbey 516641).  But skip this check in case the key came from 
        // calling VirtualPathProvider.GetCacheKey, as it may legitimately not match. 
        if (!keyFromVPP) {
            if (virtualPath != null && virtualPath != result.VirtualPath) { 
                Debug.Assert(false);
                return null;
            }
        } 

        // If what we found in the cache is a CompileError, rethrow the exception 
        if (result is BuildResultCompileError) { 
            // Report the cached error from Callback interface.
            HttpCompileException compileException = ((BuildResultCompileError)result).CompileException; 

            // But don't report it if we're doing precompilation, as that would cause it to be
            // reported twice because we always try to compile everything that has failed
            // before (VSWhidbey 525414) 
            if (!PerformingPrecompilation) {
                ReportErrorsFromException(compileException); 
            } 

            throw compileException; 
        }

        return result;
    } 

    internal static bool CacheVPathBuildResult(VirtualPath virtualPath, 
        BuildResult result, DateTime utcStart) { 

        return _theBuildManager.CacheVPathBuildResultInternal(virtualPath, result, utcStart); 
    }

    private bool CacheVPathBuildResultInternal(VirtualPath virtualPath,
        BuildResult result, DateTime utcStart) { 

        string cacheKey = GetCacheKeyFromVirtualPath(virtualPath); 
        return CacheBuildResult(cacheKey, result, utcStart); 
    }
 
    internal static bool CacheBuildResult(string cacheKey, BuildResult result, DateTime utcStart) {
        return _theBuildManager.CacheBuildResultInternal(cacheKey, result, 0 /*hashCode*/, utcStart);
    }
 
    private bool CacheBuildResultInternal(string cacheKey, BuildResult result,
        long hashCode, DateTime utcStart) { 
 
        // Before caching it, make sure the hash has been computed
        result.EnsureVirtualPathDependenciesHashComputed(); 

        for (int i = 0; i < _caches.Length; i++) {
            _caches[i].CacheBuildResult(cacheKey, result, hashCode, utcStart);
        } 

        // If we find that it's no longer valid after caching it, remove it from the cache (VSWhidbey 578372) 
        if (!TimeStampChecker.CheckFilesStillValid(cacheKey, result.VirtualPathDependencies)) { 
            _memoryCache.RemoveAssemblyAndCleanupDependencies(result as BuildResultCompiledAssemblyBase);
            return false; 
        }

        return true;
    } 

 
    // 
    // Precompilation related code
    // 

    internal void SetPrecompilationInfo(HostingEnvironmentParameters hostingParameters) {

        if (hostingParameters == null || hostingParameters.ClientBuildManagerParameter == null) 
            return;
 
        _precompilationFlags = hostingParameters.ClientBuildManagerParameter.PrecompilationFlags; 

        _strongNameKeyFile = hostingParameters.ClientBuildManagerParameter.StrongNameKeyFile; 
        _strongNameKeyContainer = hostingParameters.ClientBuildManagerParameter.StrongNameKeyContainer;

        // Check if we're precompiling to a target directory
        _precompTargetPhysicalDir = hostingParameters.PrecompilationTargetPhysicalDirectory; 
        if (_precompTargetPhysicalDir == null)
            return; 
 
        // Check if the target dir already exists and is not empty
        if (Util.IsNonEmptyDirectory(_precompTargetPhysicalDir)) { 

            // If it's not empty and OverwriteTarget is off, fail
            if ((_precompilationFlags & PrecompilationFlags.OverwriteTarget) == 0) {
                throw new HttpException(SR.GetString(SR.Dir_not_empty)); 
            }
 
            // Does it contain the precomp marker file 
            bool updatable;
            bool precompiled = ReadPrecompMarkerFile(_precompTargetPhysicalDir, out updatable); 

            // If not, refuse to delete the directory, even if OverwriteTarget is on (VSWhidbey 425095)
            if (!precompiled) {
                throw new HttpException(SR.GetString(SR.Dir_not_empty_not_precomp)); 
            }
 
            // The OverwriteTarget flag was specified, so delete the directory 
            if (!DeletePrecompTargetDirectory()) {
                // If we failed to delete it, sleep 250 ms and try again, in case there is 
                // an appdomain in the process of shutting down (the shut down would
                // have been triggered by the first delete attempt)
                Debug.Trace("BuildManager", "Failed to delete " + _precompTargetPhysicalDir + ".  Sleeping and trying once more...");
                Thread.Sleep(250); 

                if (!DeletePrecompTargetDirectory()) { 
                    Debug.Trace("BuildManager", "Failed to delete " + _precompTargetPhysicalDir + ".  Sleeping and trying once more..."); 
                    // Try again after 1 second.
                    Thread.Sleep(1000); 

                    // If we still couldn't delete it, fail
                    if (!DeletePrecompTargetDirectory()) {
                        throw new HttpException(SR.GetString(SR.Cant_delete_dir)); 
                    }
                } 
            } 
        }
 
        // Create a marker file to mark the fact that this is a precompiled app
        CreatePrecompMarkerFile();
    }
 
    private bool DeletePrecompTargetDirectory() {
        try { 
            if (_precompTargetPhysicalDir != null) { 
                // Go through all the files in the directory and delete them.
                foreach (FileData fileData in FileEnumerator.Create(_precompTargetPhysicalDir)) { 

                    if (fileData.IsDirectory) {
                        Directory.Delete(fileData.FullName, true /*recursive*/);
                    } 
                    else {
                        Util.DeleteFileNoException(fileData.FullName); 
                    } 
                }
            } 
        }
#if DEBUG
        catch (Exception e) {
            Debug.Trace("BuildManager", "DeletePrecompTargetDirectory failed: " + e.Message); 
        }
#else 
        catch {} 
#endif
        return !Util.IsNonEmptyDirectory(_precompTargetPhysicalDir); 
    }

    private void FailIfPrecompiledApp() {
 
        if (IsPrecompiledApp) {
            throw new HttpException(SR.GetString(SR.Already_precomp)); 
        } 
    }
 
    internal void PrecompileApp(ClientBuildManagerCallback callback) {

        // Remember the original setting
        bool skipTopLevelExceptions = SkipTopLevelCompilationExceptions; 

        try { 
            _cbmCallback = callback; 

            // Don't stop on the first parse errors, process as many errors as possible. 
            ThrowOnFirstParseError = false;

            // Don't skip top level compilation exceptions even called by CBM.
            SkipTopLevelCompilationExceptions = false; 

            PrecompileApp(HttpRuntime.AppDomainAppVirtualPathObject); 
        } 
        finally {
            // Revert to original setting 
            SkipTopLevelCompilationExceptions = skipTopLevelExceptions;
            ThrowOnFirstParseError = true;

            _cbmCallback = null; 
        }
    } 
 
    private void PrecompileApp(VirtualPath startingVirtualDir) {
        using (new ApplicationImpersonationContext()) { 
            try {
                PerformingPrecompilation = true;

                PrecompileAppInternal(startingVirtualDir); 
            }
            catch { 
                // If anything fails during precompilation, wipe out the target to avoid 
                // leaving it in a random state (VSWhidbey 447338)
                DeletePrecompTargetDirectory(); 

                throw;
            }
            finally { 
                PerformingPrecompilation = false;
            } 
        } 
    }
 
    private void PrecompileAppInternal(VirtualPath startingVirtualDir) {

        // If the app is already precompiled, fail
        FailIfPrecompiledApp(); 

        VirtualDirectory appVdir = startingVirtualDir.GetDirectory(); 
 
        EnsureTopLevelFilesCompiled();
 
        try {
            // Clear the parseError flag first
            _parseErrorReported = false;
 
            PrecompileWebDirectoriesRecursive(appVdir, true /*topLevel*/);
            PrecompileThemeDirectories(); 
        } 
        catch (HttpParseException parseException) {
            // if nothing calls callback.reportparseerror yet, report the parse error. 
            if (!_parseErrorReported) {
                ReportErrorsFromException(parseException);
            }
 
            throw;
        } 
 
        // Copy all the DLL's we compiled into the destination's bin directory (if any)
        if (_precompTargetPhysicalDir != null) { 
            string targetBinDir = Path.Combine(_precompTargetPhysicalDir, HttpRuntime.BinDirectoryName);
            CopyCompiledAssembliesToDestinationBin(HttpRuntime.CodegenDirInternal, targetBinDir);
        }
 
        // Copy all the static files to the destination directory (if any).  We treat anything we
        // don't compile as a static file.  It's better to do this at the end of the precompilation, 
        // this way if any pages has errors (parse or compile), we never get to this step. 
        if (_precompTargetPhysicalDir != null) {
            CopyStaticFilesRecursive(appVdir, _precompTargetPhysicalDir, true /*topLevel*/); 
        }
    }

    // Create a small file that marks that app as being precompiled 
    private void CreatePrecompMarkerFile() {
 
        Debug.Assert(PrecompilingForDeployment); 

        Directory.CreateDirectory(_precompTargetPhysicalDir); 
        string precompMarkerFile = Path.Combine(_precompTargetPhysicalDir, precompMarkerFileName);

        using (StreamWriter writer = new StreamWriter(precompMarkerFile, false /*append*/, Encoding.UTF8)) {
            writer.Write("");
        }
    } 

    private static bool ReadPrecompMarkerFile(string appRoot, out bool updatable) { 
 
        updatable = false;
 
        // Get the full physical path to the precompilation market file
        string precompMarkerFile = Path.Combine(appRoot, precompMarkerFileName);

        // If the file doesn't exist at all, it's not a precompiled app 
        if (!File.Exists(precompMarkerFile))
            return false; 
 
        XmlDocument doc = new XmlDocument();
        try { 
            doc.Load(precompMarkerFile);
        }
        catch {
            // If we fail to read it for any reason, ignore it. 
            return false;
        } 
 
        // Get the root element, and make sure it's what we expect
        XmlNode root = doc.DocumentElement; 
        Debug.Assert(root != null && root.Name == "precompiledApp");
        if (root == null || root.Name != "precompiledApp")
            return false;
 
        // Check the updatable flag
        HandlerBase.GetAndRemoveBooleanAttribute(root, "updatable", ref updatable); 
 
        return true;
    } 

    /*
     * Are we precompiling the app for deployment (as opposed to in-place)
     */ 
    internal static bool PrecompilingForDeployment {
        get { 
            return (_theBuildManager._precompTargetPhysicalDir != null); 
        }
    } 

    internal static bool PrecompilingForUpdatableDeployment {
        get {
            // The updatebale mode only applies in deployment precompilation mode 
            if (!PrecompilingForDeployment)
                return false; 
 
            return (_theBuildManager._precompilationFlags & PrecompilationFlags.Updatable) != 0;
        } 
    }

    private static bool PrecompilingForCleanBuild {
        get { 
            return (_theBuildManager._precompilationFlags & PrecompilationFlags.Clean) != 0;
        } 
    } 

    internal static bool PrecompilingWithDebugInfo { 
        get {
            // The ForceDebug flag only applies in deployment precompilation mode
            if (!PrecompilingForDeployment)
                return false; 

            return (_theBuildManager._precompilationFlags & PrecompilationFlags.ForceDebug) != 0; 
        } 
    }
 
    internal static bool PrecompilingWithCodeAnalysisSymbol {
        get {
            return (_theBuildManager._precompilationFlags & PrecompilationFlags.CodeAnalysis) != 0;
        } 
    }
 
    private static bool CompileWithFixedAssemblyNames { 
        get {
            return (_theBuildManager._precompilationFlags & PrecompilationFlags.FixedNames) != 0; 
        }
    }

    internal static bool CompileWithAllowPartiallyTrustedCallersAttribute { 
        get {
            return (_theBuildManager._precompilationFlags & PrecompilationFlags.AllowPartiallyTrustedCallers) != 0; 
        } 
    }
 
    internal static bool CompileWithDelaySignAttribute {
        get {
            return (_theBuildManager._precompilationFlags & PrecompilationFlags.DelaySign) != 0;
        } 
    }
 
    internal static string StrongNameKeyFile { 
        get {
            return _theBuildManager._strongNameKeyFile; 
        }
    }

    internal static string StrongNameKeyContainer { 
        get {
            return _theBuildManager._strongNameKeyContainer; 
        } 
    }
 
    // If we're in the process of precompiling for updatable deployment, this returns
    // a writer to the target file specified by the virtual path.  This is used when the
    // deployed file needs to be different from the original (as is the case for aspx files).
    internal static TextWriter GetUpdatableDeploymentTargetWriter(VirtualPath virtualPath, Encoding fileEncoding) { 

        Debug.Assert(fileEncoding != null); 
 
        if (!PrecompilingForUpdatableDeployment)
            return null; 

        Debug.Assert(!virtualPath.IsRelative);

        string path = virtualPath.AppRelativeVirtualPathString; 

        // Skip the "~/" to be left with the relative path 
        path = path.Substring(2); 

        // Combine it with the precomp target dir to get the full path 
        string physicalPath = Path.Combine(_theBuildManager._precompTargetPhysicalDir, path);

        // Before trying to create the file, make sure the directory exists
        string physicalDir = Path.GetDirectoryName(physicalPath); 
        Directory.CreateDirectory(physicalDir);
 
        return new StreamWriter(physicalPath, false /*append*/, fileEncoding); 
    }
 
    private bool IsPrecompiledAppInternal {
        get {
            if (!_isPrecompiledAppComputed) {
                _isPrecompiledApp = ReadPrecompMarkerFile(HttpRuntime.AppDomainAppPathInternal, 
                    out _isUpdatablePrecompiledApp);
 
                _isPrecompiledAppComputed = true; 
            }
 
            return _isPrecompiledApp;
        }
    }
 
    internal static bool IsPrecompiledApp {
        get { 
            return _theBuildManager.IsPrecompiledAppInternal; 
        }
    } 

    private bool IsUpdatablePrecompiledAppInternal {
        get {
            return IsPrecompiledApp && _isUpdatablePrecompiledApp; 
        }
    } 
 
    internal static bool IsUpdatablePrecompiledApp {
        get { 
            return _theBuildManager.IsUpdatablePrecompiledAppInternal;
        }
    }
 
    private bool IsNonUpdatablePrecompiledApp {
        get { 
            return IsPrecompiledApp && !_isUpdatablePrecompiledApp; 
        }
    } 

    private void PrecompileWebDirectoriesRecursive(VirtualDirectory vdir, bool topLevel) {

        // Precompile the children directory 

        foreach (VirtualDirectory childVdir in vdir.Directories) { 
 
            if (topLevel && _excludedTopLevelDirectories.Contains(childVdir.Name))
                continue; 

            // Exclude the special FrontPage directory (VSWhidbey 116727, 518602)
            if (childVdir.Name == "_vti_cnf")
                continue; 

            PrecompileWebDirectoriesRecursive(childVdir, false /*topLevel*/); 
        } 

        // Precompile this directory 
        try {
            // Set a flag to remember that we're in the process of precompiling.  This
            // way, if BatchCompileWebDirectory ends up getting called again recursively
            // via CompileWebFile, we know that we cannot ignore errors. 
            _precompilingApp = true;
 
            if (IsBatchEnabledForDirectory(vdir.VirtualPathObject)) { 
                // batch everything if enabled
                BatchCompileWebDirectory(vdir, null, false /*ignoreErrors*/); 
            }
            else {
                // if batching is disabled, compile each web file individually.
                NonBatchDirectoryCompiler dirCompiler = new NonBatchDirectoryCompiler(vdir); 
                dirCompiler.Process();
            } 
        } 
        finally {
            // Always restore the flag to false when we're done. 
            _precompilingApp = false;
        }
    }
 
    private void PrecompileThemeDirectories() {
        string appPhysicalDir = Path.Combine(HttpRuntime.AppDomainAppPathInternal, HttpRuntime.ThemesDirectoryName); 
 
        if (Directory.Exists(appPhysicalDir)) {
            string[] themeDirs = Directory.GetDirectories(appPhysicalDir); 

            foreach (string themeDirPath in themeDirs) {
                string themeDirName = Path.GetFileName(themeDirPath);
                ThemeDirectoryCompiler.GetThemeBuildResultType(null /*context*/, themeDirName); 
            }
        } 
    } 

    /* 
     * Recursively copy all the static files from the source directory to the
     * target directory of the precompilation
     */
    private void CopyStaticFilesRecursive(VirtualDirectory sourceVdir, string destPhysicalDir, 
        bool topLevel) {
 
        // Make sure the target physical dir has no relation with the source.  It's important to 
        // check at every new directory, because IIS apps can have disconnected virtual sub dirs,
        // making an app root check insufficient (VSWhidbey 426251) 
        string sourcePhysicalDir = HostingEnvironment.MapPathInternal(sourceVdir.VirtualPath);
        VerifyUnrelatedSourceAndDest(sourcePhysicalDir, destPhysicalDir);

        bool directoryCreationAttempted = false; 

        foreach (VirtualFileBase child in sourceVdir.Children) { 
 
            string destPhysicalSubDir = Path.Combine(destPhysicalDir, child.Name);
 
            if (child.IsDirectory) {

                // Skip the special top level directories, since they never contain relevant
                // static files.  Note that we don't skip Themes, which does contain static files. 
                if (topLevel &&
                    (StringUtil.EqualsIgnoreCase(child.Name, HttpRuntime.CodeDirectoryName) || 
                    StringUtil.EqualsIgnoreCase(child.Name, HttpRuntime.ResourcesDirectoryName) || 
                    StringUtil.EqualsIgnoreCase(child.Name, HttpRuntime.WebRefDirectoryName))) {
 
                    continue;
                }

                // Also, skip the LocalResources directory at any level, except when precompiling 
                // for updatable deployment (in which case, we deploy the local resources file)
                if (!PrecompilingForUpdatableDeployment && StringUtil.EqualsIgnoreCase(child.Name, 
                    HttpRuntime.LocalResourcesDirectoryName)) { 
                    continue;
                } 

                CopyStaticFilesRecursive(child as VirtualDirectory, destPhysicalSubDir, false /*topLevel*/);
                continue;
            } 

            // Create the destination directory if needed 
            if (!directoryCreationAttempted) { 
                directoryCreationAttempted = true;
                Directory.CreateDirectory(destPhysicalDir); 
            }

            // Copy the file as appropriate based on its extension
            CopyPrecompiledFile(child as VirtualFile, destPhysicalSubDir); 
        }
    } 
 
    /*
     * Copy all the assemblies from the codegen dir into the bin directory of the 
     * target precompiled app.
     */
    private void CopyCompiledAssembliesToDestinationBin(string fromDir, string toDir) {
 
        bool createdDirectory = false;
 
        foreach (FileData fileData in FileEnumerator.Create(fromDir)) { 
            // Windows OS Bug 1981578
            // Create a new directory only if there is something in the directory. 
            if (!createdDirectory)
                Directory.CreateDirectory(toDir);
            createdDirectory = true;
 
            // Recurse on subdirectories.if they contain culture files
            if (fileData.IsDirectory) { 
 
                if (Util.IsCultureName(fileData.Name)) {
                    string fromSubDir = Path.Combine(fromDir, fileData.Name); 
                    string toSubDir = Path.Combine(toDir, fileData.Name);
                    CopyCompiledAssembliesToDestinationBin(fromSubDir, toSubDir);
                }
 
                continue;
            } 
 
            // Only process DLL's and PDB's
            string extension = Path.GetExtension(fileData.Name); 
            if (extension != ".dll" && extension != ".pdb")
                continue;

            string sourcePhysicalPath = Path.Combine(fromDir, fileData.Name); 
            string destPhysicalPath = Path.Combine(toDir, fileData.Name);
 
            // Copy the file to the destination 
            //
            File.Copy(sourcePhysicalPath, destPhysicalPath, true /*overwrite*/); 
        }
    }

    // Copy one file from the source app to the precompiled app 
    private void CopyPrecompiledFile(VirtualFile vfile, string destPhysicalPath) {
 
        bool createStub; 

        if (CompilationUtil.NeedToCopyFile(vfile.VirtualPathObject, PrecompilingForUpdatableDeployment, 
            out createStub)) {

            //
            string sourcePhysicalPath = HostingEnvironment.MapPathInternal(vfile.VirtualPath); 

            // The file could already exist with updatable precompilation, since we would create the modified file 
            // earlier during processing of a code beside page. 
            if (File.Exists(destPhysicalPath)) {
 
                // In that case, we still need to fix it up to insert the correct type string in the
                // inherits attribute (VSWhidbey 467936)

                // First, get the just-compiled BuildResult.  It should always exist 
                BuildResultCompiledType result = GetVPathBuildResult(null, vfile.VirtualPathObject,
                    true /*noBuild*/, false /*allowCrossApp*/) as BuildResultCompiledType; 
                Debug.Assert(result != null); 

                // VSWhidbey 527299. Need to use the same encoding of the original file to 
                // read and write to the new file.
                Encoding encoding = Util.GetEncodingFromConfigPath(vfile.VirtualPathObject);

                // Read in the file 
                string newAspxFile = Util.StringFromFile(destPhysicalPath, ref encoding);
 
                // Replace the placeholder token by the true type with the assembly 
                newAspxFile = newAspxFile.Replace(UpdatableInheritReplacementToken,
                    Util.GetAssemblyQualifiedTypeName(result.ResultType)); 

                // Write the modified file back with the correct inherits type string
                StreamWriter writer = new StreamWriter(destPhysicalPath, false /* append */, encoding);
                writer.Write(newAspxFile); 
                writer.Close();
            } 
            else { 
                // Just copy the file to the destination
                File.Copy(sourcePhysicalPath, destPhysicalPath, false /*overwrite*/); 
            }

            // If it has a readonly attribute, clear it on the destination (VSWhidbey 122359)
            Util.ClearReadOnlyAttribute(destPhysicalPath); 
        }
        else { 
            if (createStub) { 
                // Create the stub file, with a helpful static message
                StreamWriter writer = new StreamWriter(destPhysicalPath); 
                writer.Write(SR.GetString(SR.Precomp_stub_file));
                writer.Close();
            }
        } 
    }
 
    // Make sure the target physical dir has no relation with the source 
    internal static void VerifyUnrelatedSourceAndDest(string sourcePhysicalDir, string destPhysicalDir) {
 
        // Make sure they're normalized and end with a '\' before comparing (VSWhidbey 452554)
        sourcePhysicalDir = FileUtil.FixUpPhysicalDirectory(sourcePhysicalDir);
        destPhysicalDir = FileUtil.FixUpPhysicalDirectory(destPhysicalDir);
 
        if (StringUtil.StringStartsWithIgnoreCase(sourcePhysicalDir, destPhysicalDir) ||
            StringUtil.StringStartsWithIgnoreCase(destPhysicalDir, sourcePhysicalDir)) { 
            throw new HttpException(SR.GetString( 
                SR.Illegal_precomp_dir, destPhysicalDir, sourcePhysicalDir));
        } 
    }

    internal static void ReportDirectoryCompilationProgress(VirtualPath virtualDir) {
 
        // Nothing to do if there is no CBM callback
        if (CBMCallback == null) 
            return; 

        // Don't report anything if the directory doesn't exist 
        if (!virtualDir.DirectoryExists())
            return;

        string message = SR.GetString(SR.Directory_progress, virtualDir.VirtualPathString); 
        CBMCallback.ReportProgress(message);
    } 
 

    // 
    // Public methods
    //

 
    /// 
    ///     Compiles a file given its virtual path, using the appropriate BuildProvider (based 
    ///     on the file's extension).  The compiled type is returned. 
    ///     This methods performs both memory and disk caching of the compiled Type.
    ///  
    public static Type GetCompiledType(string virtualPath) {
        if (virtualPath == null) {
            throw new ArgumentNullException("virtualPath");
        } 

        return GetCompiledType(VirtualPath.Create(virtualPath)); 
    } 

    // This method is called by BuildManagerHost thru CBM 
    internal static Type GetCompiledType(VirtualPath virtualPath, ClientBuildManagerCallback callback) {
        // Remember the original setting
        bool skipTopLevelExceptions = SkipTopLevelCompilationExceptions;
        bool throwOnFirstParseError = ThrowOnFirstParseError; 

        try { 
            // Don't skip top level compilation exceptions even called by CBM. 
            SkipTopLevelCompilationExceptions = false;
 
            // Don't stop on the first parse error, process as many errors as possible.
            ThrowOnFirstParseError = false;

            _theBuildManager._cbmCallback = callback; 
            return GetCompiledType(virtualPath);
        } 
        finally { 
            _theBuildManager._cbmCallback = null;
 
            // Revert to original setting
            SkipTopLevelCompilationExceptions = skipTopLevelExceptions;

            ThrowOnFirstParseError = throwOnFirstParseError; 
        }
    } 
 
    internal static Type GetCompiledType(VirtualPath virtualPath) {
        ITypedWebObjectFactory factory = GetVirtualPathObjectFactory(virtualPath, 
            null /*context*/, false /*allowCrossApp*/, false /*noAssert*/);

        BuildResultCompiledType resultType = factory as BuildResultCompiledType;
        if (resultType == null) return null; 

        return resultType.ResultType; 
    } 

    /// Process a file based on its virtual path, and instantiate the result.  This API works for both 
    /// compiled and no compile pages.  requiredBaseType specifies a type from which the resulting
    /// object must derive.  If it doesn't, the API fails without instantiating the object.
    public static object CreateInstanceFromVirtualPath(string virtualPath, Type requiredBaseType) {
        VirtualPath virtualPathObject = VirtualPath.CreateNonRelative(virtualPath); 
        return CreateInstanceFromVirtualPath(virtualPathObject, requiredBaseType,
            null /*context*/, false /*allowCrossApp*/, false /*noAssert*/); 
    } 

    ///  
    ///     Process a file given its virtual path, using the appropriate BuildProvider (based
    ///     on the file's extension).  The result is then instantiated and returned.
    /// 
    internal static object CreateInstanceFromVirtualPath(VirtualPath virtualPath, 
        Type requiredBaseType, HttpContext context, bool allowCrossApp, bool noAssert) {
 
        ITypedWebObjectFactory objectFactory = GetVirtualPathObjectFactory(virtualPath, context, allowCrossApp, noAssert); 
        if (objectFactory == null) return null;
 
        // Make sure it has the required base type (VSWhidbey 516771)
        Util.CheckAssignableType(requiredBaseType, objectFactory.InstantiatedType);

        // impersonate client while executing page ctor (see ASURT 89712) 
        // (compilation is done while not impersonating client)
 
        Object instance; 
        using (new ClientImpersonationContext(context)) {
            instance = objectFactory.CreateInstance(); 
        }

        return instance;
    } 

 
    ///  
    ///     Process a file given its virtual path, using the appropriate BuildProvider (based
    ///     on the file's extension).  The ITypedWebObjectFactory is returned. 
    ///     This methods performs both memory and disk caching of the compiled Type.
    /// 
    private static ITypedWebObjectFactory GetVirtualPathObjectFactory(VirtualPath virtualPath,
        HttpContext context, bool allowCrossApp, bool noAssert) { 

        if (virtualPath == null) 
            throw new ArgumentNullException("virtualPath"); 

        // Throw here immediately if top level exception exists. 
        // This is because EnsureTopLevelFilesCompiled (where the exception is thrown)
        // might not be called.
        if (_theBuildManager._topLevelFileCompilationException != null) {
            _theBuildManager.ReportTopLevelCompilationException(); 
        }
 
        ITypedWebObjectFactory objectFactory; 
        BuildResult buildResult;
 
        // We need to assert here since there may be user code on the stack,
        // and code may demand UnmanagedCode permission.  But if we're in full trust,
        // or noAssert is true, skip the assert for perf reasons (VSWhidbey 146871, 500699)
        if (HttpRuntime.IsFullTrust || noAssert) { 
            buildResult = GetVPathBuildResultWithNoAssert(
                context, virtualPath, false /*noBuild*/, allowCrossApp, false /*allowBuildInPrecompile*/); 
        } 
        else {
            buildResult = GetVPathBuildResultWithAssert( 
                context, virtualPath, false /*noBuild*/, allowCrossApp, false /*allowBuildInPrecompile*/);
        }

        // DevDiv 67952 
        // The returned build result may not always be castable to ITypedWebObjectFactory.
        objectFactory = buildResult as ITypedWebObjectFactory; 
 
        return objectFactory;
    } 

    /// 
    ///     Compiles a file given its virtual path, using the appropriate BuildProvider (based
    ///     on the file's extension).  The compiled assembly is returned. 
    ///     This methods performs both memory and disk caching of the compiled assembly.
    ///  
    public static Assembly GetCompiledAssembly(string virtualPath) { 

        BuildResult result = GetVPathBuildResult(VirtualPath.Create(virtualPath)); 
        if (result == null) return null;

        BuildResultCompiledAssemblyBase resultAssembly = result as BuildResultCompiledAssemblyBase;
        if (resultAssembly == null) return null; 

        return resultAssembly.ResultAssembly; 
    } 

 
    /// 
    ///     Compiles a file given its virtual path, using the appropriate BuildProvider (based
    ///     on the file's extension).  If the BuildProvider chose to persist a custom
    ///     string, the string is returned. 
    ///     This methods performs both memory and disk caching.
    ///  
    public static string GetCompiledCustomString(string virtualPath) { 

        BuildResult result = GetVPathBuildResult(VirtualPath.Create(virtualPath)); 
        if (result == null) return null;

        BuildResultCustomString resultCustomString = result as BuildResultCustomString;
        if (resultCustomString == null) return null; 

        return resultCustomString.CustomString; 
    } 

    ///  
    ///     Returns the BuildDependencySet for the passed in virtualPath, assuming
    ///     that information is cached.  Otherwise, return null.
    /// 
    public static BuildDependencySet GetCachedBuildDependencySet( 
        HttpContext context, string virtualPath) {
 
        BuildResult result = GetVPathBuildResult(context, VirtualPath.Create(virtualPath), 
            true /*noBuild*/, false /*allowCrossApp*/);
 
        // If it's not cached, return null
        if (result == null)
            return null;
 
        // We found it in the cache.  Wrap it with a BuildDependencySet object.
        return new BuildDependencySet(result); 
    } 

    private Assembly ResolveAssembly(object sender, ResolveEventArgs e) { 

        if (_assemblyResolveMapping == null)
            return null;
 
        string name = e.Name;
        Assembly assembly = (Assembly)_assemblyResolveMapping[name]; 
 
        // Return the assembly if we have it in our mapping (VSWhidbey 276776)
        if (assembly != null) { 
            return assembly;
        }

        // Get the normalized assembly name from random name (VSWhidbey 380793) 
        String normalizedName = GetNormalizedCodeAssemblyName(name);
        if (normalizedName != null) { 
            return (Assembly)_assemblyResolveMapping[normalizedName]; 
        }
 
        return null;
    }

    internal static string GetNormalizedCodeAssemblyName(string assemblyName) { 
        // Return the main code assembly.
        if (assemblyName.StartsWith(CodeDirectoryAssemblyName, StringComparison.Ordinal)) { 
            return CodeDirectoryAssemblyName; 
        }
 
        // Check the sub code directories.
        CodeSubDirectoriesCollection codeSubDirectories = CompilationUtil.GetCodeSubDirectories();
        foreach (CodeSubDirectory directory in codeSubDirectories) {
            if (assemblyName.StartsWith(SubCodeDirectoryAssemblyNamePrefix + directory.AssemblyName + ".", StringComparison.Ordinal)) { 
                return directory.AssemblyName;
            } 
        } 

        return null; 
    }

    internal static string GetNormalizedTypeName(Type t) {
        string assemblyFullName = t.Assembly.FullName; 
        string normalizedCodeAssemblyName = GetNormalizedCodeAssemblyName(assemblyFullName);
        if (normalizedCodeAssemblyName == null) { 
            return t.AssemblyQualifiedName; 
        }
 
        string normalizedTypeName = t.FullName + ", " + normalizedCodeAssemblyName;
        return normalizedTypeName;
    }
} 

internal enum CompilationStage { 
    PreTopLevelFiles = 0,       // Before EnsureTopLevelFilesCompiled() is called 
    TopLevelFiles = 1,          // In EnsureTopLevelFilesCompiled() but before building global.asax
    GlobalAsax = 2,             // While building global.asax 
    BrowserCapabilities = 3,    // While building browserCap
    AfterTopLevelFiles = 4      // After EnsureTopLevelFilesCompiled() is called
}
 
internal class AssemblyReferenceInfo {
    internal Assembly Assembly; 
    internal int ReferenceIndex; 

    internal AssemblyReferenceInfo(int referenceIndex) { 
        ReferenceIndex = referenceIndex;
    }
}
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
//------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

/************************************************************************************************************/ 
 

 
namespace System.Web.Compilation {

using System;
using System.IO; 
using System.Collections;
using System.Collections.Generic; 
using System.Collections.Specialized; 
using System.Reflection;
using System.Runtime.Remoting.Messaging; 
using System.Text;
using System.Xml;
using System.Globalization;
using System.Resources; 
using System.CodeDom;
using System.CodeDom.Compiler; 
using System.Configuration; 
using System.Web.Configuration;
using System.Web.Util; 
using System.Web.Caching;
using System.Web.UI;
#if ORCAS
using System.Web.UI.Imaging; 
#endif
using System.Web.Hosting; 
using System.Web.Profile; 
using System.Web.Security;
using System.Threading; 
using System.Security.Permissions;
using System.Web.Management;

 
/// 
///     
///       IProvider compilation related services 
///    
///  
[AspNetHostingPermission(SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Medium)]
public sealed class BuildManager {

    /// Contants relating to generated assembly names 

    // All generated assemblies start with this prefix 
    internal const string AssemblyNamePrefix = "App_"; 

    // Web assemblies are the assemblies generated from web files (aspx, ascx, ...) 
    internal const string WebAssemblyNamePrefix = AssemblyNamePrefix + "Web_";

    internal const string AppThemeAssemblyNamePrefix = AssemblyNamePrefix + "Theme_";
    internal const string GlobalThemeAssemblyNamePrefix = AssemblyNamePrefix + "GlobalTheme_"; 
    internal const string AppBrowserCapAssemblyNamePrefix = AssemblyNamePrefix + "Browsers";
 
    private const string CodeDirectoryAssemblyName = AssemblyNamePrefix + "Code"; 
    internal const string SubCodeDirectoryAssemblyNamePrefix = AssemblyNamePrefix + "SubCode_";
    private const string ResourcesDirectoryAssemblyName = AssemblyNamePrefix + "GlobalResources"; 
    private const string LocalResourcesDirectoryAssemblyName = AssemblyNamePrefix + "LocalResources";
    private const string WebRefDirectoryAssemblyName = AssemblyNamePrefix + "WebReferences";
    internal const string GlobalAsaxAssemblyName = AssemblyNamePrefix + HttpApplicationFactory.applicationFileName;
 
    private const string LicensesAssemblyName = AssemblyNamePrefix + "Licenses";
 
    internal const string UpdatableInheritReplacementToken = "__ASPNET_INHERITS"; 

    private static System.Security.Cryptography.RNGCryptoServiceProvider _rng = new System.Security.Cryptography.RNGCryptoServiceProvider(); 
    private static bool _theBuildManagerInitialized;
    private static Exception _initializeException;
    private static BuildManager _theBuildManager = new BuildManager();  // single instance of the class
    private static long s_topLevelHash; 
    internal static BuildManager TheBuildManager { get { return _theBuildManager; } }
 
    // Precompilation related fields 
    private const string precompMarkerFileName = "PrecompiledApp.config";
    private string _precompTargetPhysicalDir; 
    private PrecompilationFlags _precompilationFlags;
    private bool _isPrecompiledApp;
    private bool _isPrecompiledAppComputed;
    private bool _isUpdatablePrecompiledApp; 
    private bool _precompilingApp;  // we're in the process of precompiling an app
 
    private string _strongNameKeyFile; 
    private string _strongNameKeyContainer;
 
    private bool _optimizeCompilations;
    internal static bool OptimizeCompilations {
        get { return _theBuildManager._optimizeCompilations; }
    } 

    // filepath to the generated web.hash file, This file should only be re-created when 
    // the appdomain is restarted and the top-level generated assemblies need to be recompiled. 
    private string _webHashFilePath;
    internal static String WebHashFilePath { 
        get { return _theBuildManager._webHashFilePath; }
    }

    private BuildResultCache[] _caches; 
    private MemoryBuildResultCache _memoryCache;
 
    private bool _topLevelFilesCompiledStarted; 
    private bool _topLevelFilesCompiledCompleted;
    private Exception _topLevelFileCompilationException; 

    private BuildResultCompiledGlobalAsaxType _globalAsaxBuildResult;
    private Type _profileType;
 
    // Special top level directories that are treated differently from regular web directories
    // during precompilation (e.g. App_Code) 
    private StringSet _excludedTopLevelDirectories; 

    // Directories that are not requestable 
    private StringSet _forbiddenTopLevelDirectories;

    private StringSet _excludedCodeSubdirectories;
 
    private CompilationStage _compilationStage = CompilationStage.PreTopLevelFiles;
    internal static CompilationStage CompilationStage { get { return _theBuildManager._compilationStage; } } 
 
    private VirtualPath _scriptVirtualDir;
    private VirtualPath _globalAsaxVirtualPath; 
    internal static VirtualPath ScriptVirtualDir { get { return _theBuildManager._scriptVirtualDir; } }
    internal static VirtualPath GlobalAsaxVirtualPath { get { return _theBuildManager._globalAsaxVirtualPath; } }

    private BuildManager() { } 

    internal static bool InitializeBuildManager() { 
 
        // If we already tried and got an exception, just rethrow it
        if (_initializeException != null) { 
            // We need to wrap it in a new exception, otherwise we lose the original stack.
            throw new HttpException(_initializeException.Message, _initializeException);
        }
 
        if (!_theBuildManagerInitialized) {
 
            // If Fusion was not yet initialized, skip the init. 
            // This can happen when there is a very early failure (e.g. see VSWhidbey 137366)
            Debug.Trace("BuildManager", "InitializeBuildManager " + HttpRuntime.FusionInited); 
            if (!HttpRuntime.FusionInited)
                return false;

            // Likewise, if the trust level has not yet been determined, skip the init (VSWhidbey 422311) 
            if (HttpRuntime.TrustLevel == null)
                return false; 
 
            _theBuildManagerInitialized = true;
            try { 
                _theBuildManager.Initialize();
            }
            catch (Exception e) {
                _theBuildManagerInitialized = false; 
                _initializeException = e;
                throw; 
            } 
        }
 
        return true;
    }

    private ClientBuildManagerCallback _cbmCallback; 
    internal static ClientBuildManagerCallback CBMCallback { get { return _theBuildManager._cbmCallback; } }
 
    private static bool _parseErrorReported; 
    internal static void ReportParseError(ParserError parseError) {
        // If there is a CBM callback, inform it of the error 
        if (BuildManager.CBMCallback != null) {
            _parseErrorReported = true;
            BuildManager.CBMCallback.ReportParseError(parseError);
        } 
    }
 
    private void ReportTopLevelCompilationException() { 
        Debug.Assert(_topLevelFileCompilationException != null);
 
        // Try to report the cached error to the CBM callback
        ReportErrorsFromException(_topLevelFileCompilationException);

        // We need to wrap it in a new exception, otherwise we lose the original stack. 
        throw new HttpException(_topLevelFileCompilationException.Message,
            _topLevelFileCompilationException); 
    } 

    // Given an exception, attempt to turn it into calls to the CBM callback 
    private void ReportErrorsFromException(Exception e) {
        // If there is no CBM callback, nothing to do
        if (BuildManager.CBMCallback == null)
            return; 

        // Call the CBM callback as appropriate, based on the type of exception 
 
        if (e is HttpCompileException) {
            CompilerResults results = ((HttpCompileException) e).Results; 
            foreach (CompilerError error in results.Errors) {
                BuildManager.CBMCallback.ReportCompilerError(error);
            }
        } 
        else if (e is HttpParseException) {
            foreach (ParserError parseError in ((HttpParseException)e).ParserErrors) { 
                ReportParseError(parseError); 
            }
        } 
    }

    // The assemblies produced from the code directories and global.asax, which
    // every other compilation will linked with. 
    private List _topLevelReferencedAssemblies;
    private List TopLevelReferencedAssemblies { get { return _topLevelReferencedAssemblies; } } 
 
    private Dictionary _topLevelAssembliesIndexTable;
    private IDictionary TopLevelAssembliesIndexTable { get { return _topLevelAssembliesIndexTable; } } 

    private Dictionary _generatedFileTable;
    internal static Dictionary GenerateFileTable {
        get { 
            if (_theBuildManager._generatedFileTable == null) {
                _theBuildManager._generatedFileTable = new Dictionary(StringComparer.OrdinalIgnoreCase); 
            } 

            return _theBuildManager._generatedFileTable; 
        }
    }

    private ArrayList _codeAssemblies; 
    public static IList CodeAssemblies {
        get { 
            _theBuildManager.EnsureTopLevelFilesCompiled(); 
            return _theBuildManager._codeAssemblies;
        } 
    }

    private IDictionary _assemblyResolveMapping;
 
    private Assembly _appResourcesAssembly;
    internal static Assembly AppResourcesAssembly { get { return _theBuildManager._appResourcesAssembly; } } 
 
    // Indicates whether the parsers should coninue processing for more errors.
    // This is used in both CBM precompile-web, precompile-page and aspnet_compiler tool. 
    private bool _throwOnFirstParseError = true;
    internal static bool ThrowOnFirstParseError {
        get { return _theBuildManager._throwOnFirstParseError; }
        set { _theBuildManager._throwOnFirstParseError = value; } 
    }
 
    // Marks whether we are in the middle of performing precompilation, which affects how 
    // we deal with error handling and batching
    private bool _performingPrecompilation = false; 
    internal static bool PerformingPrecompilation {
        get { return _theBuildManager._performingPrecompilation; }
        set { _theBuildManager._performingPrecompilation = value; }
    } 

    private bool _skipTopLevelCompilationExceptions; 
    internal static bool SkipTopLevelCompilationExceptions { 
        get { return _theBuildManager._skipTopLevelCompilationExceptions; }
        set { _theBuildManager._skipTopLevelCompilationExceptions = value; } 
    }

    /*
     * Return the list of assemblies that a compilation needs to reference for a given 
     * config minus the assemblies indexed later than removeIndex
     */ 
    internal static ICollection GetReferencedAssemblies(CompilationSection compConfig, int removeIndex) { 

        AssemblySet referencedAssemblies = new AssemblySet(); 

        // Add all the config assemblies to the list
        foreach (AssemblyInfo a in compConfig.Assemblies) {
            Assembly[] assemblies = a.AssemblyInternal; 
            if (assemblies == null)
            { 
                lock (compConfig) 
                {
                    assemblies = a.AssemblyInternal; 
                    if (assemblies == null)
                        assemblies = a.AssemblyInternal = compConfig.LoadAssembly(a);
                }
            } 

            for (int i = 0; i < assemblies.Length; i++) 
            { 
                if (assemblies[i] != null) {
                    referencedAssemblies.Add(assemblies[i]); 
                }
            }
        }
 
        // Clone the top level referenced assemblies (code + global.asax + etc...), up to the removeIndex
        for (int i = 0; i < removeIndex; i++) { 
            referencedAssemblies.Add(TheBuildManager.TopLevelReferencedAssemblies[i]); 
        }
 
        return referencedAssemblies;
    }

    internal static ICollection GetReferencedAssemblies(CompilationSection compConfig) { 

        // Start by cloning the top level referenced assemblies (code + global.asax + etc...) 
        AssemblySet referencedAssemblies = AssemblySet.Create( 
            TheBuildManager.TopLevelReferencedAssemblies);
 
        // Add all the config assemblies to the list
        foreach (AssemblyInfo a in compConfig.Assemblies) {
            Assembly[] assemblies = a.AssemblyInternal;
            if (assemblies == null) 
            {
                lock (compConfig) 
                { 
                    assemblies = a.AssemblyInternal;
                    if (assemblies == null) 
                        assemblies = a.AssemblyInternal = compConfig.LoadAssembly(a);
                }
            }
 
            for (int i = 0; i < assemblies.Length; i++) {
                if (assemblies[i] != null) { 
                    referencedAssemblies.Add(assemblies[i]); 
                }
            } 
        }

        return referencedAssemblies;
    } 

 
    /* 
     * Return the list of assemblies that all page compilations need to reference. This includes
     * config assemblies ( section), bin assemblies and assemblies built from the 
     * app App_Code and other top level folders.
     */

    ///  
    /// Returns the assemblies referenced at the root application level of the current app
    ///  
    public static ICollection GetReferencedAssemblies() { 
        RuntimeConfig appConfig = RuntimeConfig.GetAppConfig();
        CompilationSection compConfig = appConfig.Compilation; 

        _theBuildManager.EnsureTopLevelFilesCompiled();

        return GetReferencedAssemblies(compConfig); 
    }
 
    /* 
     * Perform initialization work that should only be done once (per app domain).
     */ 
    private void Initialize() {

        Debug.Assert(_caches == null);
 
        // Register an AssemblyResolve event
        AppDomain.CurrentDomain.AssemblyResolve += new ResolveEventHandler(this.ResolveAssembly); 
 
        _globalAsaxVirtualPath = HttpRuntime.AppDomainAppVirtualPathObject.SimpleCombine(
            HttpApplicationFactory.applicationFileName); 

        _webHashFilePath = Path.Combine(HttpRuntime.CodegenDirInternal, "hash\\hash.web");

        // Indicate whether we should ignore the top level compilation exceptions. 
        // In CBM case, we want to continue processing the page and return partial info even
        // if the code files fail to compile. 
        _skipTopLevelCompilationExceptions = BuildManagerHost.InClientBuildManager; 

        // Deal with precompilation if we're in that mode 
        SetPrecompilationInfo(HostingEnvironment.HostingParameters);

        // The init code depends on whether we're precompiling or running an app
        if (_precompTargetPhysicalDir != null) { 

            // If the app is already precompiled, fail 
            FailIfPrecompiledApp(); 

            PrecompilationModeInitialize(); 
        }
        else {
            // Check if this application has been precompiled by aspnet_compiler.exe
            if (IsPrecompiledApp) { 
                PrecompiledAppRuntimeModeInitialize();
            } 
            else { 
                RegularAppRuntimeModeInitialize();
            } 
        }

        _scriptVirtualDir = Util.GetScriptLocation();
 
        // Top level directories that have a special semantic
        _excludedTopLevelDirectories = new CaseInsensitiveStringSet(); 
        _excludedTopLevelDirectories.Add(HttpRuntime.BinDirectoryName); 
        _excludedTopLevelDirectories.Add(HttpRuntime.CodeDirectoryName);
        _excludedTopLevelDirectories.Add(HttpRuntime.ResourcesDirectoryName); 
        _excludedTopLevelDirectories.Add(HttpRuntime.LocalResourcesDirectoryName);
        _excludedTopLevelDirectories.Add(HttpRuntime.WebRefDirectoryName);
        _excludedTopLevelDirectories.Add(HttpRuntime.ThemesDirectoryName);
 
        // Top level directories that are not requestable
        // It's the same as _excludedTopLevelDirectories, except that we allow 
        // the bin directory to avoid a v1 breaking change (VSWhidbey 465018) 
        _forbiddenTopLevelDirectories = new CaseInsensitiveStringSet();
        _forbiddenTopLevelDirectories.Add(HttpRuntime.CodeDirectoryName); 
        _forbiddenTopLevelDirectories.Add(HttpRuntime.ResourcesDirectoryName);
        _forbiddenTopLevelDirectories.Add(HttpRuntime.LocalResourcesDirectoryName);
        _forbiddenTopLevelDirectories.Add(HttpRuntime.WebRefDirectoryName);
        _forbiddenTopLevelDirectories.Add(HttpRuntime.ThemesDirectoryName); 

        LoadLicensesAssemblyIfExists(); 
    } 

    /* 
     * Init code used when we are running a non-precompiled app
     */
    private void RegularAppRuntimeModeInitialize() {
 
        //
        // Initialize the caches 
        // 

        // Always try the memory cache first 
        _memoryCache = new MemoryBuildResultCache(HttpRuntime.CacheInternal);

        // Use the standard disk cache for regular apps
        StandardDiskBuildResultCache diskCache = new StandardDiskBuildResultCache( 
            HttpRuntime.CodegenDirInternal);
 
        _caches = new BuildResultCache[] { _memoryCache, diskCache }; 

        CheckTopLevelFilesUpToDate(diskCache); 
    }

    /*
     * Init code used when we are running a precompiled app 
     */
    private void PrecompiledAppRuntimeModeInitialize() { 
 
        //
        // Initialize the caches 
        //

        // Always try the memory cache first
        _memoryCache = new MemoryBuildResultCache(HttpRuntime.CacheInternal); 

        // Used the precomp cache for precompiled apps 
        BuildResultCache preCompCache = new PrecompiledSiteDiskBuildResultCache( 
            HttpRuntime.BinDirectoryInternal);
 
        // Also create a regular disk cache so that we can compile and cache additional things.
        // This is useful even in non-updatable precomp, to cache DefaultWsdlHelpGenerator.aspx.

        StandardDiskBuildResultCache diskCache = new StandardDiskBuildResultCache( 
            HttpRuntime.CodegenDirInternal);
 
        _caches = new BuildResultCache[] { _memoryCache, preCompCache, diskCache }; 

        CheckTopLevelFilesUpToDate(diskCache); 
    }

    /*
     * Init code used when we are precompiling an app 
     */
    private void PrecompilationModeInitialize() { 
 
        // We are precompiling an app
 
        // Always try the memory cache first
        _memoryCache = new MemoryBuildResultCache(HttpRuntime.CacheInternal);

        // Create a regular disk cache, to take advantage of the fact that the app 
        // may already have been compiled (and to cause it to be if it wasn't)
        StandardDiskBuildResultCache diskCache = new StandardDiskBuildResultCache( 
            HttpRuntime.CodegenDirInternal); 

        // Create a special disk cache in the target's bin directory.  Use a slightly different 
        // implementation for the updatable case.
        string targetBinDir = Path.Combine(_precompTargetPhysicalDir, HttpRuntime.BinDirectoryName);
        BuildResultCache preCompilationCache;
        if (PrecompilingForUpdatableDeployment) { 
            preCompilationCache = new UpdatablePrecompilerDiskBuildResultCache(targetBinDir);
        } 
        else { 
            preCompilationCache = new PrecompilerDiskBuildResultCache(targetBinDir);
        } 

        _caches = new BuildResultCache[] { _memoryCache, preCompilationCache, diskCache  };

        CheckTopLevelFilesUpToDate(diskCache); 
    }
 
    // Load the licenses assembly from the bin dir if it exists (DevDiv 42149) 
    private void LoadLicensesAssemblyIfExists() {
        string licAssemblyPath = Path.Combine(HttpRuntime.BinDirectoryInternal, LicensesAssemblyName + ".dll"); 
        if (File.Exists(licAssemblyPath)) {
            Assembly.Load(LicensesAssemblyName);
        }
    } 

    private void CheckTopLevelFilesUpToDate(StandardDiskBuildResultCache diskCache) { 
 
        bool gotLock = false;
 
        try {
            // Grab the compilation mutex, since this method accesses the codegen files
            CompilationLock.GetLock(ref gotLock);
 
            CheckTopLevelFilesUpToDate2(diskCache);
        } 
        finally { 
            // Always release the mutex if we had taken it
            if (gotLock) { 
                CompilationLock.ReleaseLock();
            }
        }
    } 

    /* 
     * Check if the top level files are up to date, and cleanup the codegendir 
     * if they are not.
     */ 
    private void CheckTopLevelFilesUpToDate2(StandardDiskBuildResultCache diskCache) {

        long specialFilesCombinedHash = diskCache.GetPreservedSpecialFilesCombinedHash();
        Debug.Trace("BuildManager", "specialFilesCombinedHash=" + specialFilesCombinedHash); 

        // Delete all the non essential files left over in the codegen dir, unless 
        // specialFilesCombinedHash is 0, in which case we delete *everything* further down 
        if (specialFilesCombinedHash != 0)
            diskCache.RemoveOldTempFiles(); 

        // Use a HashCodeCombiner object to handle the time stamps of all the 'special'
        // files and directories that all compilations depend on:
        // - System.Web.dll (in case there is a newer version of ASP.NET) 
        // - ~\Bin directory
        // - ~\Resource directory 
        // - ~\WebReferences directory 
        // - ~\Code directory
        // - global.asax 

        HashCodeCombiner specialFilesDateTimeCombiner = new HashCodeCombiner();

        // Add a check for the app's physical path, in case it changes (ASURT 12975) 
        specialFilesDateTimeCombiner.AddObject(HttpRuntime.AppDomainAppPathInternal);
 
        // Process System.Web.dll 
        string aspBinaryFileName = typeof(HttpRuntime).Module.FullyQualifiedName;
        specialFilesDateTimeCombiner.AddFile(aspBinaryFileName); 

        // Process machine.config
        string machineConfigFileName = HttpConfigurationSystem.MachineConfigurationFilePath;
        specialFilesDateTimeCombiner.AddFile(machineConfigFileName); 

        // Process root web.config 
        string rootWebConfigFileName = HttpConfigurationSystem.RootWebConfigurationFilePath; 
        specialFilesDateTimeCombiner.AddFile(rootWebConfigFileName);
 
        RuntimeConfig appConfig = RuntimeConfig.GetAppConfig();
        CompilationSection compConfig = appConfig.Compilation;

        // Ignore the OptimizeCompilations flag in ClientBuildManager mode 
        if (!BuildManagerHost.InClientBuildManager) {
            _optimizeCompilations = compConfig.OptimizeCompilations; 
        } 

        // In optimized compilation mode, we don't clean out all the compilations just because a top level 
        // file changes.  Instead, we let already compiled pages run against the newer top level binaries.
        // In can be incorrect in some cases (e.g. return type of method changes from int to short), which is
        // why the optimization is optional
        if (!OptimizeCompilations) { 
            // Add a dependency of the bin, resources, webresources and code directories
            string binPhysicalDir = HttpRuntime.BinDirectoryInternal; 
            specialFilesDateTimeCombiner.AddDirectory(binPhysicalDir); 

            // Note that we call AddResourcesDirectory instead of AddDirectory, since we only want 
            // culture neutral files to be taken into account (VSWhidbey 359029)
            specialFilesDateTimeCombiner.AddResourcesDirectory(HttpRuntime.ResourcesDirectoryVirtualPath.MapPathInternal());

            specialFilesDateTimeCombiner.AddDirectory(HttpRuntime.WebRefDirectoryVirtualPath.MapPathInternal()); 

            specialFilesDateTimeCombiner.AddDirectory(HttpRuntime.CodeDirectoryVirtualPath.MapPathInternal()); 
 
            // Add a dependency on the global asax file.
            specialFilesDateTimeCombiner.AddFile(GlobalAsaxVirtualPath.MapPathInternal()); 
        }

        // Add a dependency on the hash of the app level  section, since it
        // affects all compilations, including the code directory.  It it changes, 
        // we may as well, start all over.
        specialFilesDateTimeCombiner.AddObject(compConfig.RecompilationHash); 
 
        ProfileSection profileSection = appConfig.Profile;
        specialFilesDateTimeCombiner.AddObject(profileSection.RecompilationHash); 

        // Add a dependency on file encoding (DevDiv 4560)
        specialFilesDateTimeCombiner.AddObject(appConfig.Globalization.FileEncoding);
 
        // Also add a dependency on the  config section
        TrustSection casConfig = appConfig.Trust; 
        specialFilesDateTimeCombiner.AddObject(casConfig.Level); 
        specialFilesDateTimeCombiner.AddObject(casConfig.OriginUrl);
 
        // Add a dependency on whether profile is enabled
        specialFilesDateTimeCombiner.AddObject(ProfileManager.Enabled);

        // Add a dependency to the force debug flag. 
        specialFilesDateTimeCombiner.AddObject(PrecompilingWithDebugInfo);
 
        // Store the top level hash 
        s_topLevelHash = specialFilesDateTimeCombiner.CombinedHash;
 
        if (PrecompilingForCleanBuild || specialFilesDateTimeCombiner.CombinedHash != specialFilesCombinedHash) {
            if (PrecompilingForCleanBuild) {
                Debug.Trace("BuildManager", "Precompiling for clean build.");
            } 
            else {
                Debug.Trace("BuildManager", "EnsureFirstTimeInit: hash codes don't match.  Old=" + 
                    specialFilesCombinedHash + " New=" + specialFilesDateTimeCombiner.CombinedHash); 
            }
 
            diskCache.RemoveAllCodegenFiles();
            diskCache.SavePreservedSpecialFilesCombinedHash(specialFilesDateTimeCombiner.CombinedHash);
        }
        else { 
            Debug.Trace("BuildManager", "BuildManager: the special files are up to date");
        } 
 
        Debug.Assert(File.Exists(_webHashFilePath));
 
        // VSWhidbey 537929 : Setup a filechange monitor for the web.hash file. If this file is modified,
        // we will need to shutdown the appdomain so we don't use the obsolete assemblies. The new appdomain
        // will use the up-to-date assemblies.
        HttpRuntime.FileChangesMonitor.StartMonitoringFile(_webHashFilePath, 
            new FileChangeEventHandler(this.OnWebHashFileChange));
    } 
 
    private void OnWebHashFileChange(Object sender, FileChangeEvent e) {
        // Shutdown the app domain 
        Debug.Trace("BuildManager", _webHashFilePath + " changed - shutting down the app domain");
        Debug.Trace("AppDomainFactory", "Shutting down appdomain because " + _webHashFilePath + " file changed");

        HttpRuntime.ShutdownAppDomain(ApplicationShutdownReason.BuildManagerChange, "Change in " + _webHashFilePath); 
    }
 
    /* 
     * Check if an assembly name is reserved for a special purpose
     */ 
    internal static bool IsReservedAssemblyName(string assemblyName) {

        if (String.Compare(assemblyName, CodeDirectoryAssemblyName,
                StringComparison.OrdinalIgnoreCase) == 0 || 
            String.Compare(assemblyName, ResourcesDirectoryAssemblyName,
                StringComparison.OrdinalIgnoreCase) == 0 || 
            String.Compare(assemblyName, WebRefDirectoryAssemblyName, 
                StringComparison.OrdinalIgnoreCase) == 0 ||
            String.Compare(assemblyName, GlobalAsaxAssemblyName, 
                StringComparison.OrdinalIgnoreCase) == 0) {

            return true;
        } 

        return false; 
    } 

    // excludedSubdirectories contains a list of subdirectory names that should not be 
    // recursively included in the compilation (they'll instead be compiled into their
    // own assemblies).
    private Assembly CompileCodeDirectory(VirtualPath virtualDir, CodeDirectoryType dirType,
        string assemblyName, StringSet excludedSubdirectories) { 

        Debug.Trace("BuildManager", "CompileCodeDirectory(" + virtualDir.VirtualPathString + ")"); 
 
        bool isDirectoryAllowed = true;
        if (IsPrecompiledApp) { 
            // Most special dirs are not allowed in precompiled apps.  App_LocalResources is
            // an exception, as it is allowed in updatable precompiled apps.
            if (IsUpdatablePrecompiledAppInternal && dirType == CodeDirectoryType.LocalResources)
                isDirectoryAllowed = true; 
            else
                isDirectoryAllowed = false; 
        } 

        // Remember the referenced assemblies based on the current count. 
        AssemblyReferenceInfo info = new AssemblyReferenceInfo(_topLevelReferencedAssemblies.Count);
        _topLevelAssembliesIndexTable[virtualDir.VirtualPathString] = info;

        Assembly codeAssembly = CodeDirectoryCompiler.GetCodeDirectoryAssembly( 
                virtualDir, dirType, assemblyName, excludedSubdirectories,
                isDirectoryAllowed); 
 
        if (codeAssembly != null) {
 
            // Remember the generated assembly
            info.Assembly = codeAssembly;

            // Page resource assemblies are not added to the top level list 
            if (dirType != CodeDirectoryType.LocalResources) {
                _topLevelReferencedAssemblies.Add(codeAssembly); 
 
                if (dirType == CodeDirectoryType.MainCode || dirType == CodeDirectoryType.SubCode) {
                    if (_codeAssemblies == null) { 
                        _codeAssemblies = new ArrayList();
                    }

                    _codeAssemblies.Add(codeAssembly); 
                }
 
                // Add it to the list of assembly name that we resolve, so that users can 
                // refer to the assemblies by their fixed name (even though they
                // random names).  (VSWhidbey 276776) 
                if (_assemblyResolveMapping == null) {
                    _assemblyResolveMapping = new Hashtable(StringComparer.OrdinalIgnoreCase);
                }
                _assemblyResolveMapping[assemblyName] = codeAssembly; 

                if (dirType == CodeDirectoryType.MainCode) { 
                    // Profile gets built in the same assembly as the main code dir, so 
                    // see whether we can get its type from the assembly.
                    _profileType = ProfileBuildProvider.GetProfileTypeFromAssembly( 
                        codeAssembly, IsPrecompiledApp);

                    // To avoid breaking earlier Whidbey apps, allows the name "__code"
                    // to be used for the main code assembly. 
                    //
                    _assemblyResolveMapping["__code"] = codeAssembly; 
                } 
            }
        } 

        Debug.Trace("BuildManager", "CompileCodeDirectory generated assembly: " +
            (codeAssembly == null ? "None" : codeAssembly.ToString()));
 
        return codeAssembly;
    } 
 

    private void CompileResourcesDirectory() { 

        VirtualPath virtualDir = HttpRuntime.ResourcesDirectoryVirtualPath;

        Debug.Assert(_appResourcesAssembly == null); 
        _appResourcesAssembly = CompileCodeDirectory(virtualDir, CodeDirectoryType.AppResources,
            ResourcesDirectoryAssemblyName, null /*excludedSubdirectories*/); 
    } 

    private void CompileWebRefDirectory() { 

        CompileCodeDirectory(HttpRuntime.WebRefDirectoryVirtualPath, CodeDirectoryType.WebReferences,
            WebRefDirectoryAssemblyName, null /*excludedSubdirectories*/);
    } 

    // Compute the list of subdirectories that should not be compiled with 
    // the top level Code 
    private void EnsureExcludedCodeSubDirectoriesComputed() {
 
        if (_excludedCodeSubdirectories != null)
            return;

        _excludedCodeSubdirectories = new CaseInsensitiveStringSet(); 

        // Get the list of sub directories that will be compiled separately 
        CodeSubDirectoriesCollection codeSubDirectories = CompilationUtil.GetCodeSubDirectories(); 

        // Add them to the exclusion list of the top level code directory 
        if (codeSubDirectories != null) {
            foreach (CodeSubDirectory entry in codeSubDirectories) {
                _excludedCodeSubdirectories.Add(entry.DirectoryName);
            } 
        }
    } 
 
    private void CompileCodeDirectories() {
 
        VirtualPath virtualDir = HttpRuntime.CodeDirectoryVirtualPath;

        // Get the list of sub directories that will be compiled separately
        CodeSubDirectoriesCollection codeSubDirectories = CompilationUtil.GetCodeSubDirectories(); 

        if (codeSubDirectories != null) { 
 
            // Compile all the subdirectory that are listed in config.
 
            foreach (CodeSubDirectory entry in codeSubDirectories) {

                //
 

 
                VirtualPath virtualSubDir = virtualDir.SimpleCombineWithDir(entry.DirectoryName); 

                string assemblyName = SubCodeDirectoryAssemblyNamePrefix + entry.AssemblyName; 

                // Compile the subdirectory tree (no exclusions)
                CompileCodeDirectory(virtualSubDir, CodeDirectoryType.SubCode, assemblyName,
                    null /*excludedSubdirectories*/); 
            }
        } 
 
        EnsureExcludedCodeSubDirectoriesComputed();
 
        // Compile the top level Code directory tree, minus the excluded subdirectories
        CompileCodeDirectory(virtualDir, CodeDirectoryType.MainCode,
            CodeDirectoryAssemblyName, _excludedCodeSubdirectories);
    } 

    private void CompileGlobalAsax() { 
        _globalAsaxBuildResult = ApplicationBuildProvider.GetGlobalAsaxBuildResult(IsPrecompiledApp); 

        // Make sure that global.asax notifications are set up (VSWhidbey 267245) 
        HttpApplicationFactory.SetupFileChangeNotifications();

        if (_globalAsaxBuildResult != null) {
 
            // We need to add not only the global.asax type, but also its parent types to
            // the top level assembly list.  This can happen when global.asax has a 'src' 
            // attribute pointing to a source file containing its base type. 
            Type type = _globalAsaxBuildResult.ResultType;
 
            while (type.Assembly != typeof(HttpRuntime).Assembly) {
                _topLevelReferencedAssemblies.Add(type.Assembly);

                type = type.BaseType; 
            }
        } 
    } 

    // Call the AppInitialize method in the Code assembly if there is one 
    internal static void CallAppInitializeMethod() {

        // Make sure the code directory has been processed
        _theBuildManager.EnsureTopLevelFilesCompiled(); 

        CodeDirectoryCompiler.CallAppInitializeMethod(); 
    } 

    internal void EnsureTopLevelFilesCompiled() { 

        // This should never get executed in non-hosted appdomains
        Debug.Assert(HostingEnvironment.IsHosted);
 
        // If we already tried and got an exception, just rethrow it
        if (_topLevelFileCompilationException != null && !SkipTopLevelCompilationExceptions) { 
            ReportTopLevelCompilationException(); 
        }
 
        if(_topLevelFilesCompiledStarted)
            return;

        // Set impersonation to hosting identity (process or UNC) 
        using (new ApplicationImpersonationContext()) {
            bool gotLock = false; 
            _parseErrorReported = false; 

            try { 
                // Grab the compilation mutex, since this method accesses the codegen files
                CompilationLock.GetLock(ref gotLock);

                // Check again if there is an exception 
                if (_topLevelFileCompilationException != null && !SkipTopLevelCompilationExceptions) {
                    ReportTopLevelCompilationException(); 
                } 

                // Check again if we're done 
                if(_topLevelFilesCompiledStarted)
                    return;

                _topLevelFilesCompiledStarted = true; 
                _topLevelReferencedAssemblies = new List();
                _topLevelAssembliesIndexTable = 
                    new Dictionary(StringComparer.OrdinalIgnoreCase); 

                // 
                _topLevelReferencedAssemblies.Add(typeof(HttpRuntime).Assembly);
                _topLevelReferencedAssemblies.Add(typeof(System.ComponentModel.Component).Assembly);

                _compilationStage = CompilationStage.TopLevelFiles; 

                CompileResourcesDirectory(); 
                CompileWebRefDirectory(); 
                CompileCodeDirectories();
 
                _compilationStage = CompilationStage.GlobalAsax;

                CompileGlobalAsax();
 
                _compilationStage = CompilationStage.BrowserCapabilities;
 
                // Call GetBrowserCapabilitiesType() to make sure browserCap directory is compiled 
                // early on.  This avoids getting into potential deadlock situations later (VSWhidbey 530732).
                // For the same reason, get the EmptyHttpCapabilitiesBase. 
                BrowserCapabilitiesCompiler.GetBrowserCapabilitiesType();
                IFilterResolutionService dummy = HttpCapabilitiesBase.EmptyHttpCapabilitiesBase;

                _compilationStage = CompilationStage.AfterTopLevelFiles; 
            }
            catch (Exception e) { 
                // Remember the exception, and rethrow it 
                _topLevelFileCompilationException = e;
 
                // Do not rethrow the exception since so CBM can still provide partial support
                if (!SkipTopLevelCompilationExceptions) {

                    if (!_parseErrorReported) { 
                        // Report the error if this is not a CompileException. CompileExceptions are handled
                        // directly by the AssemblyBuilder already. 
                        if (!(e is HttpCompileException)) { 
                            ReportTopLevelCompilationException();
                        } 
                    }

                    throw;
                } 
            }
            finally { 
                _topLevelFilesCompiledCompleted = true; 

                // Always release the mutex if we had taken it 
                if (gotLock) {
                    CompilationLock.ReleaseLock();
                }
            } 
        }
    } 
 
    // Generate a random file name with 8 characters
    private static string GenerateRandomFileName() { 
        // Generate random bytes
        byte[] data = new byte[6];

        lock (_rng) { 
            _rng.GetBytes(data);
        } 
 
        // Turn them into a string containing only characters valid in file names/url
        string s = Convert.ToBase64String(data).ToLower(CultureInfo.InvariantCulture); 
        s = s.Replace('/', '-');
        s = s.Replace('+', '_');

        return s; 
    }
 
    internal static string GenerateRandomAssemblyName(string baseName) { 
        return GenerateRandomAssemblyName(baseName, true /*topLevel*/);
    } 

    // Generate a random name for an assembly, starting with the passed in prefix
    internal static string GenerateRandomAssemblyName(string baseName, bool topLevel) {
 
        // Start with the passed in base name
        string assemblyName = baseName; 
 
        // Append a random token to it.
 
        // However, don't do this when precompiling for deployment since, we want the name to be more predictable (DevDiv 36625)
        if (PrecompilingForDeployment)
            return baseName;
 
        // Also, don't use random names for top level files in OptimizeCompilations mode so that pages
        // can more easily bind against rebuilt top level assemblies 
        if (OptimizeCompilations && topLevel) 
            return baseName;
 
        return baseName += "." + GenerateRandomFileName();
    }

    private static string GetGeneratedAssemblyBaseName(VirtualPath virtualPath) { 

        // Name the assembly using the same scheme as cache keys 
        return GetCacheKeyFromVirtualPath(virtualPath); 
    }
 
    /*
     * Look for a type by name in the top level and config assemblies
     */
    public static Type GetType(string typeName, bool throwOnError) { 
        return GetType(typeName, throwOnError, false);
    } 
 
    /*
     * Look for a type by name in the top level and config assemblies 
     */
    public static Type GetType(string typeName, bool throwOnError, bool ignoreCase) {
        // If it contains an assembly name, just call Type.GetType().  Do this before even trying
        // to initialize the BuildManager, so that if InitializeBuildManager has errors, it doesn't 
        // affect us when the type string can be resolved via Type.GetType().
        Type type = null; 
        if (Util.TypeNameContainsAssembly(typeName)) { 
            type = Type.GetType(typeName, throwOnError, ignoreCase);
 
            if (type != null) {
                    return type;
            }
        } 

        // Make sure the build manager is initialized.  If it fails to initialize for any reason, 
        // don't attempt to use the fancy GetType logic.  Just call Type.GetType instead (VSWhidbey 284498) 
        if (!InitializeBuildManager()) {
            return Type.GetType(typeName, throwOnError, ignoreCase); 
        }

        // First, always try System.Web.dll
        try { 
            type = typeof(BuildManager).Assembly.GetType(typeName,
                false /*throwOnError*/, ignoreCase); 
        } 
        catch (ArgumentException e) {
            // Even though we pass false to throwOnError, GetType can throw if the 
            // assembly name is malformed.  In that case, throw our own error instead
            // of the cryptic ArgumentException (VSWhidbey 275586)
            throw new HttpException(
                SR.GetString(SR.Invalid_type, typeName), e); 
        }
 
        if (type != null) return type; 

        _theBuildManager.EnsureTopLevelFilesCompiled(); 

        // Otherwise, look for the type in the top level assemblies
        type = Util.GetTypeFromAssemblies(TheBuildManager.TopLevelReferencedAssemblies,
            typeName, ignoreCase); 
        if (type != null) return type;
 
        // Otherwise, look for the type in the config assemblies 
        AssemblyCollection configAssemblies = CompilationUtil.GetAssembliesForAppLevel();
        if (configAssemblies != null) { 
            Type t = CompilationUtil.GetTypeFromAssemblies(configAssemblies, typeName, ignoreCase);
            if (t != null) {
                // If we had already found a different one, it's an ambiguous type reference
                if (type != null && t != type) { 
                    throw new HttpException(SR.GetString(
                        SR.Ambiguous_type, typeName, Util.GetAssemblySafePathFromType(type), 
                        Util.GetAssemblySafePathFromType(t))); 
                }
 
                type = t;
            }
        }
 
        if (type == null && throwOnError) {
            throw new HttpException( 
                SR.GetString(SR.Invalid_type, typeName)); 
        }
 
        return type;
    }

    /* 
     * Gets a type from one of the code assemblies
     */ 
    internal static Type GetTypeFromCodeAssembly(string typeName, bool ignoreCase) { 

        // No code assembly: return 
        if (CodeAssemblies == null)
            return null;

        return Util.GetTypeFromAssemblies(CodeAssemblies, typeName, ignoreCase); 
    }
 
    internal static BuildProvider CreateBuildProvider(VirtualPath virtualPath, 
        CompilationSection compConfig, ICollection referencedAssemblies,
        bool failIfUnknown) { 

        return CreateBuildProvider(virtualPath, BuildProviderAppliesTo.Web,
            compConfig, referencedAssemblies, failIfUnknown);
    } 

    internal static BuildProvider CreateBuildProvider(VirtualPath virtualPath, 
        BuildProviderAppliesTo neededFor, 
        CompilationSection compConfig, ICollection referencedAssemblies,
        bool failIfUnknown) { 

        string extension = virtualPath.Extension;

        Type buildProviderType = CompilationUtil.GetBuildProviderTypeFromExtension(compConfig, 
            extension, neededFor, failIfUnknown);
        if (buildProviderType == null) 
            return null; 

        object o = HttpRuntime.CreatePublicInstance(buildProviderType); 

        BuildProvider buildProvider = (BuildProvider) o;

        buildProvider.SetVirtualPath(virtualPath); 
        buildProvider.SetReferencedAssemblies(referencedAssemblies);
 
        return buildProvider; 
    }
 
    internal static void ValidateCodeFileVirtualPath(VirtualPath virtualPath) {
        _theBuildManager.ValidateVirtualPathInternal(virtualPath, false /*allowCrossApp*/, true /*codeFile*/);
    }
 
    private void ValidateVirtualPathInternal(VirtualPath virtualPath, bool allowCrossApp, bool codeFile) {
 
        if (!allowCrossApp) { 
            virtualPath.FailIfNotWithinAppRoot();
        } 
        else {
            // If cross app is allowed, and the path is in a different app, nothing more to check
            if (!virtualPath.IsWithinAppRoot)
                return; 
        }
 
        // 
        // Now, detect if it's under a special directory (e.g. 'code', 'resources', 'themes')
        // 

        // If it's exactly the app root, it's fine
        if (HttpRuntime.AppDomainAppVirtualPathObject == virtualPath)
            return; 

        int appPathLen = HttpRuntime.AppDomainAppVirtualPathString.Length; 
 
        string virtualPathString = virtualPath.VirtualPathString;
 
        // This could happen if the vpath is "/app" (while the app vpath is "/app/")
        if (virtualPathString.Length < appPathLen)
            return;
 
        // If no slash after the approot (e.g. "/app/foo.aspx"), it's valid
        int slashIndex = virtualPathString.IndexOf('/', appPathLen); 
        if (slashIndex < 0) 
            return;
 
        // Get the name of the first directory under the app root (e.g. "/app/aaa/bbb/foo.aspx" -> "aaa")
        string dir = virtualPathString.Substring(appPathLen, slashIndex - appPathLen);

        // If it's a forbidden directory, fail 
        if (_forbiddenTopLevelDirectories.Contains(dir)) {
            throw new HttpException(SR.GetString( 
                SR.Illegal_special_dir, virtualPathString, dir)); 
        }
    } 

    /*
     * Returns a single hash code that represents the state of the built object for
     * the passed in virtualPath.  If it isn't already built, don't build it, but just 
     * return 0.  This can be used to determine the validity of output cache that
     * has been persisted to disk. 
     */ 
    internal static long GetBuildResultHashCodeIfCached(
        HttpContext context, string virtualPath) { 

        BuildResult result = GetVPathBuildResult(context, VirtualPath.Create(virtualPath),
            true /*noBuild*/, false /*allowCrossApp*/);
 
        // If it's not cached, return 0
        if (result == null) 
            return 0; 

        // Return a single hash code based on both of the BuildResult's hash codes 
        string dependenciesHash = result.VirtualPathDependenciesHash;
        Debug.Assert(result.DependenciesHashComputed);
        return result.ComputeHashCode(s_topLevelHash, StringUtil.GetStringHashCode(dependenciesHash));
    } 

    internal static BuildResult GetVPathBuildResult(VirtualPath virtualPath) { 
 
        return GetVPathBuildResult(null /*context*/, virtualPath,
            false /*noBuild*/, false /*allowCrossApp*/, false /*allowBuiltInPrecompile*/); 
    }

    internal static BuildResult GetVPathBuildResult(HttpContext context, VirtualPath virtualPath) {
 
        return GetVPathBuildResult(context, virtualPath, false /*noBuild*/, false /*allowCrossApp*/, false /*allowBuiltInPrecompile*/);
    } 
 
    internal static BuildResult GetVPathBuildResult(HttpContext context, VirtualPath virtualPath,
        bool noBuild, bool allowCrossApp) { 

        return GetVPathBuildResult(context, virtualPath, noBuild, allowCrossApp, false /*allowBuiltInPrecompile*/);
    }
 
    /*
     * Calls either GetVPathBuildResultWithNoAssert or GetVPathBuildResultWithAssert, 
     * depending on whether there is any point in asserting. 
     */
    internal static BuildResult GetVPathBuildResult(HttpContext context, VirtualPath virtualPath, 
        bool noBuild, bool allowCrossApp, bool allowBuildInPrecompile) {

        // Could be called with user code on the stack, so need to assert here (VSWhidbey 85026)
        // e.g. This can happen during a Server.Transfer, or a LoadControl. 
        // But if we're running in full trust, skip the assert for perf reasons (VSWhidbey 146871)
        if (HttpRuntime.IsFullTrust) { 
            return GetVPathBuildResultWithNoAssert(context, virtualPath, noBuild, allowCrossApp, allowBuildInPrecompile); 
        }
        else { 
            return GetVPathBuildResultWithAssert(context, virtualPath, noBuild, allowCrossApp, allowBuildInPrecompile);
        }
    }
 
    /*
     * Same as GetVPathBuildResultWithNoAssert, but with an Unrestricted Assert. 
     */ 
    [PermissionSet(SecurityAction.Assert, Unrestricted=true)]
    internal static BuildResult GetVPathBuildResultWithAssert( 
        HttpContext context, VirtualPath virtualPath, bool noBuild, bool allowCrossApp, bool allowBuildInPrecompile) {

        return GetVPathBuildResultWithNoAssert(context, virtualPath, noBuild, allowCrossApp, allowBuildInPrecompile);
    } 

    internal static BuildResult GetVPathBuildResultWithNoAssert( 
        HttpContext context, VirtualPath virtualPath, bool noBuild, bool allowCrossApp, bool allowBuildInPrecompile) { 

        using (new ApplicationImpersonationContext()) { 
            return _theBuildManager.GetVPathBuildResultInternal(virtualPath, noBuild, allowCrossApp, allowBuildInPrecompile);
        }
    }
 
    // name of the slot in call context
    private const String CircularReferenceCheckerSlotName = "CircRefChk"; 
 
    private BuildResult GetVPathBuildResultInternal(VirtualPath virtualPath, bool noBuild, bool allowCrossApp, bool allowBuildInPrecompile) {
 
        Debug.Trace("BuildManager", "GetBuildResult(" + virtualPath + ")");

        // This should never be called while building top level files (VSWhidbey 480256)
        if (_compilationStage == CompilationStage.TopLevelFiles) { 
            throw new HttpException(SR.GetString(SR.Too_early_for_webfile, virtualPath));
        } 
 
        // Make sure the path is not relative
        Debug.Assert(!virtualPath.IsRelative); 

        // Try the cache first before getting the mutex
        BuildResult result = GetVPathBuildResultFromCacheInternal(virtualPath);
        if (result != null) 
            return result;
 
        // If we were only checking the cache and it wasn't there, return null. 
        if (noBuild)
            return null; 

        // Check if it's trying to go cross app, or points to a special directory.
        // It's important to do this before checkin existence, to avoid revealing information
        // about other apps (VSWhidbey 442632) 
        ValidateVirtualPathInternal(virtualPath, allowCrossApp, false /*codeFile*/);
 
        // Before grabbing the lock, make sure the file at least exists (ASURT 46465) 
        Util.CheckVirtualFileExists(virtualPath);
 
        // If this is a precompiled app, complain if we couldn't find it in the cache
        if (IsNonUpdatablePrecompiledApp && !allowBuildInPrecompile) {
            throw new HttpException(
                SR.GetString(SR.Cant_update_precompiled_app, virtualPath)); 
        }
 
        bool gotLock = false; 

        try { 
            // Grab the compilation mutex
            CompilationLock.GetLock(ref gotLock);

            // Check the cache a second time after getting the mutex 
            result = GetVPathBuildResultFromCacheInternal(virtualPath);
            if (result != null) 
                return result; 

            // Get the circular reference checker (create it if needed) 
            VirtualPathSet circularReferenceChecker;
            circularReferenceChecker = CallContext.GetData(CircularReferenceCheckerSlotName)
                as VirtualPathSet;
            if (circularReferenceChecker == null) { 
                circularReferenceChecker = new VirtualPathSet();
 
                // Create it and save it in the CallContext 
                CallContext.SetData(CircularReferenceCheckerSlotName, circularReferenceChecker);
            } 

            // If a circular reference is detected, throw an error
            if (circularReferenceChecker.Contains(virtualPath)) {
                throw new HttpException( 
                    SR.GetString(SR.Circular_include));
            } 
 
            // Add the current virtualPath to the circular reference checker
            circularReferenceChecker.Add(virtualPath); 

            try {
                //
                EnsureTopLevelFilesCompiled(); 
                result = CompileWebFile(virtualPath);
            } 
            finally { 
                // Remove the current virtualPath from the circular reference checker
                Debug.Assert(circularReferenceChecker.Contains(virtualPath)); 
                circularReferenceChecker.Remove(virtualPath);
            }
        }
        finally { 
            // Always release the mutex if we had taken it
            if (gotLock) { 
                CompilationLock.ReleaseLock(); 
            }
        } 

        return result;
    }
 
    private BuildResult CompileWebFile(VirtualPath virtualPath) {
 
        BuildResult result = null; 

        if (_topLevelFilesCompiledCompleted) { 

            VirtualPath parentPath = virtualPath.Parent;

            // First, try to batch the directory if enabled 
            if (IsBatchEnabledForDirectory(parentPath)) {
                BatchCompileWebDirectory(null, parentPath, true /*ignoreErrors*/); 
 
                // If successful, it would have been cached to memory
                string cacheKey = GetCacheKeyFromVirtualPath(virtualPath); 
                result = _memoryCache.GetBuildResult(cacheKey);

                if (result != null) {
                    // If what we found in the cache is a CompileError, rethrow the exception 
                    if (result is BuildResultCompileError) {
                        throw ((BuildResultCompileError)result).CompileException; 
                    } 

                    return result; 
                }
            }
        }
 

        DateTime utcStart = DateTime.UtcNow; 
 
        // Name the assembly based on the virtual path, in order to get a recognizable name
        string outputAssemblyName = BuildManager.WebAssemblyNamePrefix + 
            BuildManager.GenerateRandomAssemblyName(
            GetGeneratedAssemblyBaseName(virtualPath), false /*topLevel*/);

        BuildProvidersCompiler bpc = new BuildProvidersCompiler(virtualPath /*configPath*/, outputAssemblyName); 

        // Create a BuildProvider based on the virtual path 
        BuildProvider buildProvider = CreateBuildProvider(virtualPath, bpc.CompConfig, 
            bpc.ReferencedAssemblies, true /*failIfUnknown*/);
 
        // Set the BuildProvider using a single item collection
        bpc.SetBuildProviders(new SingleObjectCollection(buildProvider));

        // Compile it 
        CompilerResults results;
 
        try { 
            results = bpc.PerformBuild();
            result = buildProvider.GetBuildResult(results); 
        }
        catch (HttpCompileException e) {

            // If we're not supposed to cache the exception, just rethrow it 
            if (e.DontCache)
                throw; 
 
            result = new BuildResultCompileError(virtualPath, e);
 
            // Add the dependencies to the compile error build provider, so that
            // we will retry compilation when a dependency changes
            buildProvider.SetBuildResultDependencies(result);
 
            // Remember the virtualpath dependencies, so that we will correctly
            // invalidate buildresult when depdency changes. 
            e.VirtualPathDependencies = buildProvider.VirtualPathDependencies; 

            // Cache it for next time 
            CacheVPathBuildResultInternal(virtualPath, result, utcStart);

            // Set the DontCache flag, so that the exception will not be incorrectly
            // cached again lower down the stack (VSWhidbey 128234) 
            e.DontCache = true;
 
            throw; 
        }
 
        if (result == null)
            return null;

        // Cache it for next time 
        CacheVPathBuildResultInternal(virtualPath, result, utcStart);
 
        return result; 
    }
 
    // Hashtbale to remember the local resources assembly for each directory (or null
    // if there isn't one). Hashtable
    private Hashtable _localResourcesAssemblies = new Hashtable();
 
    private void EnsureFirstTimeDirectoryInit(VirtualPath virtualDir) {
 
        // Don't process local resources when precompiling for updatable deployment. 
        // Instead, we deploy the App_LocalResources folder as is.
        if (PrecompilingForUpdatableDeployment) 
            return;

        if (virtualDir == null)
            return; 

        // Only do this once per directory 
        if (_localResourcesAssemblies.Contains(virtualDir)) 
            return;
 
        // Don't do anything if it's outside the app root
        if (!virtualDir.IsWithinAppRoot)
            return;
 
        Debug.Trace("BuildManager", "EnsureFirstTimeDirectoryInit(" + virtualDir + ")");
 
        // Get the virtual path to the LocalResources subdirectory for this directory 
        VirtualPath localResDir = virtualDir.SimpleCombineWithDir(HttpRuntime.LocalResourcesDirectoryName);
 
        bool dirExists;
        try {
            dirExists = localResDir.DirectoryExists();
        } 
        catch {
            // If an exception happens, the directory may be outside the application, 
            // in which case we should skip this logic, and act is if there are no 
            // local resources (VSWhidbey 258776);
 
            _localResourcesAssemblies[virtualDir] = null;
            return;
        }
 
        Debug.Trace("BuildManager", "EnsureFirstTimeDirectoryInit: dirExists=" + dirExists);
 
        try { 
            // Monitor changes to it so the appdomain can shut down when it changes
            HttpRuntime.StartListeningToLocalResourcesDirectory(localResDir); 
        }
        catch {
            // could fail for long directory names
            if (dirExists) { 
                throw;
            } 
        } 

        Assembly resourceAssembly = null; 

        // If it exists, build it
        if (dirExists) {
 
            string localResAssemblyName = GetLocalResourcesAssemblyName(virtualDir);
 
            bool gotLock = false; 

            try { 
                // Grab the compilation mutex, since this method accesses the codegen files
                CompilationLock.GetLock(ref gotLock);

                resourceAssembly = CompileCodeDirectory(localResDir, CodeDirectoryType.LocalResources, 
                    localResAssemblyName, null /*excludedSubdirectories*/);
            } 
            finally { 
                // Always release the mutex if we had taken it
                if (gotLock) { 
                    CompilationLock.ReleaseLock();
                }
            }
        } 

        // Cache it whether it's null or not 
        _localResourcesAssemblies[virtualDir] = resourceAssembly; 
    }
 
    // VSWhidbey Bug 560521
    private void EnsureFirstTimeDirectoryInitForDependencies(ICollection dependencies) {
        foreach (String dependency in dependencies) {
            VirtualPath dependencyPath = VirtualPath.Create(dependency); 
            VirtualPath dir = dependencyPath.Parent;
            EnsureFirstTimeDirectoryInit(dir); 
        } 
    }
 

    // Retrieve a cached local resources assembly (could be null)
    internal static Assembly GetLocalResourcesAssembly(VirtualPath virtualDir) {
        return (Assembly) _theBuildManager._localResourcesAssemblies[virtualDir]; 
    }
 
    internal static string GetLocalResourcesAssemblyName(VirtualPath virtualDir) { 
        return LocalResourcesDirectoryAssemblyName + "." + GetGeneratedAssemblyBaseName(virtualDir);
    } 

    // name of the slot in call context
    private const String BatchCompilationSlotName = "BatchCompileChk";
 
    // Check if batching is enabled for directory specified by virtualDir
    private bool IsBatchEnabledForDirectory(VirtualPath virtualDir) { 
        // False if compile for fixed name 
        if (CompileWithFixedAssemblyNames) {
            return false; 
        }

        // Always enable batching for deployement
        if (PrecompilingForDeployment) { 
            return true;
        } 
 
        // If it's called by other non-precompile CBM methods, always disable batching
        if (BuildManagerHost.InClientBuildManager && !PerformingPrecompilation) { 
            return false;
        }

        // Check the config 
        return CompilationUtil.IsBatchingEnabled(virtualDir.VirtualPathString);
    } 
 
    private bool BatchCompileWebDirectory(VirtualDirectory vdir, VirtualPath virtualDir, bool ignoreErrors) {
 
        // Exactly one of vdir and virtualDir should be non-null.  The idea is to avoid calling
        // VirtualPathProvider.GetDirectory if batching is disabled (VSWhidbey 437549).

        if (virtualDir == null) 
            virtualDir = vdir.VirtualPathObject;
 
        if (vdir == null) 
            vdir = HostingEnvironment.VirtualPathProvider.GetDirectory(virtualDir);
 
        // Then, check if we're already tried batch compiling this directory on this same request

        CaseInsensitiveStringSet directoryBatchCompilerChecker;
        directoryBatchCompilerChecker = CallContext.GetData(BatchCompilationSlotName) 
            as CaseInsensitiveStringSet;
 
        if (directoryBatchCompilerChecker == null) { 
            directoryBatchCompilerChecker = new CaseInsensitiveStringSet();
 
            // Create it and save it in the CallContext
            CallContext.SetData(BatchCompilationSlotName, directoryBatchCompilerChecker);
        }
 
        // If we've already tried batch compiling this directory, don't do anything
        if (directoryBatchCompilerChecker.Contains(vdir.VirtualPath)) 
            return false; 

        // Add the current virtualDir to the batch compiler checker 
        directoryBatchCompilerChecker.Add(vdir.VirtualPath);

        // If we're in the process of precompiling an app, never ignore errors.
        if (_precompilingApp) 
            ignoreErrors = false;
 
        return BatchCompileWebDirectoryInternal(vdir, ignoreErrors); 
    }
 
    private bool BatchCompileWebDirectoryInternal(VirtualDirectory vdir, bool ignoreErrors) {

        WebDirectoryBatchCompiler sdc = new WebDirectoryBatchCompiler(vdir);
 
        // Just ignore build providers that have errors
        if (ignoreErrors) { 
            sdc.SetIgnoreErrors(); 

            // Don't propagate errors that happen during batch compilation 
            try {
                sdc.Process();
            }
            catch { 
                return false;
            } 
        } 
        else {
            sdc.Process(); 
        }

        return true;
    } 

    internal static Type GetGlobalAsaxType() { 
        return _theBuildManager.GetGlobalAsaxTypeInternal(); 
    }
 
    private Type GetGlobalAsaxTypeInternal() {
        EnsureTopLevelFilesCompiled();

        if (_globalAsaxBuildResult == null) 
            return typeof(HttpApplication);
 
        return _globalAsaxBuildResult.ResultType; 
    }
 
    internal static BuildResultCompiledGlobalAsaxType GetGlobalAsaxBuildResult() {
        return _theBuildManager.GetGlobalAsaxBuildResultInternal();
    }
 
    private BuildResultCompiledGlobalAsaxType GetGlobalAsaxBuildResultInternal() {
        EnsureTopLevelFilesCompiled(); 
 
        return _globalAsaxBuildResult;
    } 

    internal string[] GetCodeDirectories() {

        VirtualPath virtualDir = HttpRuntime.CodeDirectoryVirtualPath; 

        // If there is no Code directory, return an empty array 
        if (!virtualDir.DirectoryExists()) 
            return new string[0];
 
        // Get the list of code sub directories that will be compiled separately
        CodeSubDirectoriesCollection codeSubDirectories = CompilationUtil.GetCodeSubDirectories();

        // Compute the number of code dirs, including the root one 
        int numOfCodeDirs = 1;
        if (codeSubDirectories != null) 
            numOfCodeDirs += codeSubDirectories.Count; 

        string[] codeDirs = new string[numOfCodeDirs]; 
        int current = 0;

        if (codeSubDirectories != null) {
            foreach (CodeSubDirectory entry in codeSubDirectories) { 

                VirtualPath virtualSubDir = virtualDir.SimpleCombineWithDir(entry.DirectoryName); 
                codeDirs[current++] = virtualSubDir.VirtualPathString; 
            }
        } 

        // Add the root code dir at the end of the list (since it's compiled last)
        codeDirs[current++] = virtualDir.VirtualPathString;
 
        return codeDirs;
    } 
 
    internal void GetCodeDirectoryInformation(VirtualPath virtualCodeDir,
        out Type codeDomProviderType, out CompilerParameters compilerParameters, 
        out string generatedFilesDir) {

        // Backup the compilation stage, since the call will modify it
        CompilationStage savedCompilationStage = _compilationStage; 

        try { 
            GetCodeDirectoryInformationInternal(virtualCodeDir, out codeDomProviderType, 
                out compilerParameters, out generatedFilesDir);
        } 
        finally {
            // Restore the compilation stage
            _compilationStage = savedCompilationStage;
        } 
    }
 
    private void GetCodeDirectoryInformationInternal(VirtualPath virtualCodeDir, 
        out Type codeDomProviderType, out CompilerParameters compilerParameters,
        out string generatedFilesDir) { 

        StringSet excludedSubdirectories = null;

        CodeDirectoryType dirType; 

        // Get the DirectoryType based on the path 
        if (virtualCodeDir == HttpRuntime.CodeDirectoryVirtualPath) { 

            // If it's the top level code directory, make sure we exclude any 
            // subdirectories that are compiled separately
            EnsureExcludedCodeSubDirectoriesComputed();

            excludedSubdirectories = _excludedCodeSubdirectories; 

            dirType = CodeDirectoryType.MainCode; 
 
            _compilationStage = CompilationStage.TopLevelFiles;
        } 
        else if (virtualCodeDir == HttpRuntime.ResourcesDirectoryVirtualPath) {

            dirType = CodeDirectoryType.AppResources;
 
            _compilationStage = CompilationStage.TopLevelFiles;
        } 
        // If virtualCodeDir is a subdir of WebReference virtual path. 
        else if (String.Compare(virtualCodeDir.VirtualPathString, 0,
            HttpRuntime.WebRefDirectoryVirtualPath.VirtualPathString, 0, HttpRuntime.WebRefDirectoryVirtualPath.VirtualPathString.Length, 
            StringComparison.OrdinalIgnoreCase) == 0) {

            // Use the top WebReference directory info for its sub directories.
            virtualCodeDir = HttpRuntime.WebRefDirectoryVirtualPath; 
            dirType = CodeDirectoryType.WebReferences;
 
            _compilationStage = CompilationStage.TopLevelFiles; 
        }
        else if (String.Compare(virtualCodeDir.FileName, HttpRuntime.LocalResourcesDirectoryName, 
            StringComparison.OrdinalIgnoreCase) == 0) {

            dirType = CodeDirectoryType.LocalResources;
 
            // LocalResources are compiled *after* top level files
            _compilationStage = CompilationStage.AfterTopLevelFiles; 
        } 
        else {
            // If all else fails, treat it as a sub directory 
            //
            dirType = CodeDirectoryType.SubCode;

            // Sub-code dirs are compiled *before* the main code dir 
            _compilationStage = CompilationStage.TopLevelFiles;
        } 
 
        Debug.Assert(virtualCodeDir.HasTrailingSlash);
        AssemblyReferenceInfo info = TheBuildManager.TopLevelAssembliesIndexTable[virtualCodeDir.VirtualPathString]; 
        if (info == null) {
            throw new InvalidOperationException(
                SR.GetString(SR.Invalid_CodeSubDirectory_Not_Exist, virtualCodeDir));
        } 

        // Get the info we need for this code directory 
        CodeDirectoryCompiler.GetCodeDirectoryInformation( 
            virtualCodeDir, dirType, excludedSubdirectories, info.ReferenceIndex,
            out codeDomProviderType, out compilerParameters, 
            out generatedFilesDir);

        Assembly resultAssembly = info.Assembly;
 
        if (resultAssembly != null) {
            // Use the runtime generated assembly location. VSWhidbey 400335 
            compilerParameters.OutputAssembly = resultAssembly.Location; 
        }
    } 

    internal static Type GetProfileType() {
        return _theBuildManager.GetProfileTypeInternal();
    } 

    private Type GetProfileTypeInternal() { 
        EnsureTopLevelFilesCompiled(); 
        return _profileType;
    } 


    //
    // Caching related code 
    //
 
 
    public static ICollection GetVirtualPathDependencies(string virtualPath) {
 
        CompilationSection compConfig = RuntimeConfig.GetRootWebConfig().Compilation;

        // Create a BuildProvider based on the virtual path
        BuildProvider buildProvider = CreateBuildProvider(VirtualPath.Create(virtualPath), compConfig, 
            null, false /*failIfUnknown*/);
 
        if (buildProvider == null) 
            return null;
 
        // Get its dependencies
        //
        return buildProvider.GetBuildResultVirtualPathDependencies();
    } 

#if OLD 
    /* 
     * Rewrite the virtualPath if appropriate, in order to support ghosting
     */ 
    private static void GetGhostedVirtualPath(ref string virtualPath) {

        VirtualPathProvider virtualPathProvider = HostingEnvironment.VirtualPathProvider;
 
        string ghostedVirtualPath = virtualPathProvider.GetGhostedVirtualPath(virtualPath);
 
        // If the file is not ghosted, don't change the path 
        if (ghostedVirtualPath == null)
            return; 

        //

 
        // Get the list of virtual paths that it depends on (e.g. user controls)
        ICollection virtualPathDependencies = GetVirtualPathDependencies(virtualPath); 
 
        // If there aren't any, return the ghosted path
        if (virtualPathDependencies == null) { 
            virtualPath = ghostedVirtualPath;
            return;
        }
 
        // Go through all the dependencies, and if we find any that is *not* ghosted
        // (i.e. for which GetGhostedVirtualPath returns null), we treat the whole request 
        // as unghosted (and hence we return without modifying the virtualPath). 

        foreach (string virtualDependency in virtualPathDependencies) { 
            string ghostedVirtualDependencyPath = virtualPathProvider.GetGhostedVirtualPath(
                virtualDependency);
            if (ghostedVirtualDependencyPath == null)
                return; 
        }
 
        // All the dependencies are ghosted, so we can safely use the ghosted path, 
        // which can then be shared for all fully ghosted requests.
        virtualPath = ghostedVirtualPath; 
    }
#endif

    internal static string GetCacheKeyFromVirtualPath(VirtualPath virtualPath) { 
        bool keyFromVPP;
        return GetCacheKeyFromVirtualPath(virtualPath, out keyFromVPP); 
    } 

    /* 
     * Same as GetCacheKeyFromVirtualPathInternal, but caches the cache keys
     * for performance, since creating them is expensive (VSWhidbey 146540)
     */
    static SimpleRecyclingCache _keyCache = new SimpleRecyclingCache(); 
    private static string GetCacheKeyFromVirtualPath(VirtualPath virtualPath, out bool keyFromVPP) {
 
        // Check if the VirtualPathProvider needs to use a non-default cache key 
        string key = virtualPath.GetCacheKey();
 
        // If so, just return it
        if (key != null) {
            keyFromVPP = true;
            return key.ToLowerInvariant(); 
        }
 
        // The VPP didn't return a key, so use our standard key algorithm 
        keyFromVPP = false;
 
        // Check if the key for this virtual path is already cached
        key = _keyCache[virtualPath.VirtualPathString] as string;
        if (key != null) return key;
 
        // Compute the key
        key = GetCacheKeyFromVirtualPathInternal(virtualPath); 
 
        // The key should always be lower case
        Debug.Assert(key == key.ToLowerInvariant()); 

        // Cache it for next time
        _keyCache[virtualPath.VirtualPathString] = key;
 
        return key;
    } 
 
    /*
     * Generate a unique cache key from a virtual path.  e.g. for "/approot/sub1/sub2/foo.aspx" 
     * the key could be "foo.aspx.ccdf220e", where ccdf220e is a hash code from
     * the dir "sub1/sub2".
     */
    private static string GetCacheKeyFromVirtualPathInternal(VirtualPath virtualPath) { 

        // We want the key to be app independent (for precompilation), so we 
        // change the virtual path to be app relative 

        /* Disable assertion since global theme needs to compile theme files in different vroot. 
        Debug.Assert(StringUtil.VirtualPathStartsWithAppPath(virtualPath),
            String.Format("VPath {0} is outside the application: {1}", virtualPath, HttpRuntime.AppDomainAppVirtualPath));
        */
        string virtualPathString = virtualPath.AppRelativeVirtualPathString.ToLowerInvariant(); 
        virtualPathString = UrlPath.RemoveSlashFromPathIfNeeded(virtualPathString);
 
        // Split the path into the directory and the name 
        int slashIndex = virtualPathString.LastIndexOf('/');
        Debug.Assert(slashIndex >= 0 || virtualPathString == "~"); 

        if (virtualPathString == "~")
            return "root";
 
        Debug.Assert(slashIndex != virtualPathString.Length - 1);
        string name = virtualPathString.Substring(slashIndex + 1); 
        string dir; 
        if (slashIndex <= 0)
            dir = "/"; 
        else {
            dir = virtualPathString.Substring(0, slashIndex);
        }
 
        return name + "." + StringUtil.GetStringHashCode(dir).ToString("x", CultureInfo.InvariantCulture);
    } 
 
    internal static BuildResult GetVPathBuildResultFromCache(VirtualPath virtualPath) {
 
        return TheBuildManager.GetVPathBuildResultFromCacheInternal(virtualPath);
    }

    private BuildResult GetVPathBuildResultFromCacheInternal(VirtualPath virtualPath) { 

        bool keyFromVPP; 
        string cacheKey = GetCacheKeyFromVirtualPath(virtualPath, out keyFromVPP); 
        return GetBuildResultFromCacheInternal(cacheKey, keyFromVPP, virtualPath, 0 /*hashCode*/);
    } 

    internal static BuildResult GetBuildResultFromCache(string cacheKey) {
        return _theBuildManager.GetBuildResultFromCacheInternal(cacheKey, false /*keyFromVPP*/, null /*virtualPath*/,
            0 /*hashCode*/); 
    }
 
    internal static BuildResult GetBuildResultFromCache(string cacheKey, VirtualPath virtualPath) { 
        return _theBuildManager.GetBuildResultFromCacheInternal(cacheKey, false /*keyFromVPP*/, virtualPath,
            0 /*hashCode*/); 
    }

    private BuildResult GetBuildResultFromCacheInternal(string cacheKey, bool keyFromVPP,
        VirtualPath virtualPath, long hashCode) { 

        BuildResult result = null; 
 
        // Allow the possibility that BuildManager was not initialized due to
        // a very early failure (e.g. see VSWhidbey 137366) 
        //Debug.Trace("BuildManager", "GetBuildResultFromCacheInternal " + _theBuildManagerInitialized);
        if (!_theBuildManagerInitialized)
            return null;
 
        // The first cache should always be memory
        Debug.Assert(_caches[0] == _memoryCache); 
 
        // Try to get it from the memeory cache before taking any locks (for perf reasons)
        result = _memoryCache.GetBuildResult(cacheKey, virtualPath, hashCode); 
        if (result != null) {
            return PostProcessFoundBuildResult(result, keyFromVPP, virtualPath);
        }
 
        Debug.Trace("BuildManager", "Didn't find '" + virtualPath + "' in memory cache before lock");
 
        lock (this) { 
            // Try to get the BuildResult from the cheapest to most expensive cache
            int i; 
            for (i = 0; i < _caches.Length; i++) {
                result = _caches[i].GetBuildResult(cacheKey, virtualPath, hashCode);

                // There might be changes in local resources for dependencies, 
                // so we need to make sure EnsureFirstTimeDirectoryInit gets called
                // for them even when we already have a cache result. 
                // VSWhidbey Bug 560521 

                if (result != null) { 
                    if (result.VirtualPathDependencies != null) {
                        EnsureFirstTimeDirectoryInitForDependencies(result.VirtualPathDependencies);
                    }
 
                    break;
                } 
 
                // If we didn't find it in the memory cache, perform the per directory
                // initialization.  This is a good place to do this, because we don't 
                // affect the memory cache code path, but we do the init as soon as
                // something is not found in the memory cache.
                if (i == 0 && virtualPath != null) {
                    VirtualPath virtualDir = virtualPath.Parent; 
                    EnsureFirstTimeDirectoryInit(virtualDir);
                } 
            } 

 
            if (result == null)
                return null;

            result = PostProcessFoundBuildResult(result, keyFromVPP, virtualPath); 
            if (result == null)
                return null; 
 
            Debug.Assert(_memoryCache != null);
 
            // If we found it in a cache, cache it in all the caches that come before
            // the one where we found it.  If we found it in the memory cache, this is a no op.
            for (int j = 0; j < i; j++)
                _caches[j].CacheBuildResult(cacheKey, result, DateTime.UtcNow); 

            Debug.Trace("BuildManager", "Found '" + virtualPath + "' in " + _caches[i]); 
 
            return result;
        } 
    }

    private BuildResult PostProcessFoundBuildResult(BuildResult result, bool keyFromVPP, VirtualPath virtualPath) {
 
        // Check that the virtual path in the result matches the passed in
        // virtualPath (VSWhidbey 516641).  But skip this check in case the key came from 
        // calling VirtualPathProvider.GetCacheKey, as it may legitimately not match. 
        if (!keyFromVPP) {
            if (virtualPath != null && virtualPath != result.VirtualPath) { 
                Debug.Assert(false);
                return null;
            }
        } 

        // If what we found in the cache is a CompileError, rethrow the exception 
        if (result is BuildResultCompileError) { 
            // Report the cached error from Callback interface.
            HttpCompileException compileException = ((BuildResultCompileError)result).CompileException; 

            // But don't report it if we're doing precompilation, as that would cause it to be
            // reported twice because we always try to compile everything that has failed
            // before (VSWhidbey 525414) 
            if (!PerformingPrecompilation) {
                ReportErrorsFromException(compileException); 
            } 

            throw compileException; 
        }

        return result;
    } 

    internal static bool CacheVPathBuildResult(VirtualPath virtualPath, 
        BuildResult result, DateTime utcStart) { 

        return _theBuildManager.CacheVPathBuildResultInternal(virtualPath, result, utcStart); 
    }

    private bool CacheVPathBuildResultInternal(VirtualPath virtualPath,
        BuildResult result, DateTime utcStart) { 

        string cacheKey = GetCacheKeyFromVirtualPath(virtualPath); 
        return CacheBuildResult(cacheKey, result, utcStart); 
    }
 
    internal static bool CacheBuildResult(string cacheKey, BuildResult result, DateTime utcStart) {
        return _theBuildManager.CacheBuildResultInternal(cacheKey, result, 0 /*hashCode*/, utcStart);
    }
 
    private bool CacheBuildResultInternal(string cacheKey, BuildResult result,
        long hashCode, DateTime utcStart) { 
 
        // Before caching it, make sure the hash has been computed
        result.EnsureVirtualPathDependenciesHashComputed(); 

        for (int i = 0; i < _caches.Length; i++) {
            _caches[i].CacheBuildResult(cacheKey, result, hashCode, utcStart);
        } 

        // If we find that it's no longer valid after caching it, remove it from the cache (VSWhidbey 578372) 
        if (!TimeStampChecker.CheckFilesStillValid(cacheKey, result.VirtualPathDependencies)) { 
            _memoryCache.RemoveAssemblyAndCleanupDependencies(result as BuildResultCompiledAssemblyBase);
            return false; 
        }

        return true;
    } 

 
    // 
    // Precompilation related code
    // 

    internal void SetPrecompilationInfo(HostingEnvironmentParameters hostingParameters) {

        if (hostingParameters == null || hostingParameters.ClientBuildManagerParameter == null) 
            return;
 
        _precompilationFlags = hostingParameters.ClientBuildManagerParameter.PrecompilationFlags; 

        _strongNameKeyFile = hostingParameters.ClientBuildManagerParameter.StrongNameKeyFile; 
        _strongNameKeyContainer = hostingParameters.ClientBuildManagerParameter.StrongNameKeyContainer;

        // Check if we're precompiling to a target directory
        _precompTargetPhysicalDir = hostingParameters.PrecompilationTargetPhysicalDirectory; 
        if (_precompTargetPhysicalDir == null)
            return; 
 
        // Check if the target dir already exists and is not empty
        if (Util.IsNonEmptyDirectory(_precompTargetPhysicalDir)) { 

            // If it's not empty and OverwriteTarget is off, fail
            if ((_precompilationFlags & PrecompilationFlags.OverwriteTarget) == 0) {
                throw new HttpException(SR.GetString(SR.Dir_not_empty)); 
            }
 
            // Does it contain the precomp marker file 
            bool updatable;
            bool precompiled = ReadPrecompMarkerFile(_precompTargetPhysicalDir, out updatable); 

            // If not, refuse to delete the directory, even if OverwriteTarget is on (VSWhidbey 425095)
            if (!precompiled) {
                throw new HttpException(SR.GetString(SR.Dir_not_empty_not_precomp)); 
            }
 
            // The OverwriteTarget flag was specified, so delete the directory 
            if (!DeletePrecompTargetDirectory()) {
                // If we failed to delete it, sleep 250 ms and try again, in case there is 
                // an appdomain in the process of shutting down (the shut down would
                // have been triggered by the first delete attempt)
                Debug.Trace("BuildManager", "Failed to delete " + _precompTargetPhysicalDir + ".  Sleeping and trying once more...");
                Thread.Sleep(250); 

                if (!DeletePrecompTargetDirectory()) { 
                    Debug.Trace("BuildManager", "Failed to delete " + _precompTargetPhysicalDir + ".  Sleeping and trying once more..."); 
                    // Try again after 1 second.
                    Thread.Sleep(1000); 

                    // If we still couldn't delete it, fail
                    if (!DeletePrecompTargetDirectory()) {
                        throw new HttpException(SR.GetString(SR.Cant_delete_dir)); 
                    }
                } 
            } 
        }
 
        // Create a marker file to mark the fact that this is a precompiled app
        CreatePrecompMarkerFile();
    }
 
    private bool DeletePrecompTargetDirectory() {
        try { 
            if (_precompTargetPhysicalDir != null) { 
                // Go through all the files in the directory and delete them.
                foreach (FileData fileData in FileEnumerator.Create(_precompTargetPhysicalDir)) { 

                    if (fileData.IsDirectory) {
                        Directory.Delete(fileData.FullName, true /*recursive*/);
                    } 
                    else {
                        Util.DeleteFileNoException(fileData.FullName); 
                    } 
                }
            } 
        }
#if DEBUG
        catch (Exception e) {
            Debug.Trace("BuildManager", "DeletePrecompTargetDirectory failed: " + e.Message); 
        }
#else 
        catch {} 
#endif
        return !Util.IsNonEmptyDirectory(_precompTargetPhysicalDir); 
    }

    private void FailIfPrecompiledApp() {
 
        if (IsPrecompiledApp) {
            throw new HttpException(SR.GetString(SR.Already_precomp)); 
        } 
    }
 
    internal void PrecompileApp(ClientBuildManagerCallback callback) {

        // Remember the original setting
        bool skipTopLevelExceptions = SkipTopLevelCompilationExceptions; 

        try { 
            _cbmCallback = callback; 

            // Don't stop on the first parse errors, process as many errors as possible. 
            ThrowOnFirstParseError = false;

            // Don't skip top level compilation exceptions even called by CBM.
            SkipTopLevelCompilationExceptions = false; 

            PrecompileApp(HttpRuntime.AppDomainAppVirtualPathObject); 
        } 
        finally {
            // Revert to original setting 
            SkipTopLevelCompilationExceptions = skipTopLevelExceptions;
            ThrowOnFirstParseError = true;

            _cbmCallback = null; 
        }
    } 
 
    private void PrecompileApp(VirtualPath startingVirtualDir) {
        using (new ApplicationImpersonationContext()) { 
            try {
                PerformingPrecompilation = true;

                PrecompileAppInternal(startingVirtualDir); 
            }
            catch { 
                // If anything fails during precompilation, wipe out the target to avoid 
                // leaving it in a random state (VSWhidbey 447338)
                DeletePrecompTargetDirectory(); 

                throw;
            }
            finally { 
                PerformingPrecompilation = false;
            } 
        } 
    }
 
    private void PrecompileAppInternal(VirtualPath startingVirtualDir) {

        // If the app is already precompiled, fail
        FailIfPrecompiledApp(); 

        VirtualDirectory appVdir = startingVirtualDir.GetDirectory(); 
 
        EnsureTopLevelFilesCompiled();
 
        try {
            // Clear the parseError flag first
            _parseErrorReported = false;
 
            PrecompileWebDirectoriesRecursive(appVdir, true /*topLevel*/);
            PrecompileThemeDirectories(); 
        } 
        catch (HttpParseException parseException) {
            // if nothing calls callback.reportparseerror yet, report the parse error. 
            if (!_parseErrorReported) {
                ReportErrorsFromException(parseException);
            }
 
            throw;
        } 
 
        // Copy all the DLL's we compiled into the destination's bin directory (if any)
        if (_precompTargetPhysicalDir != null) { 
            string targetBinDir = Path.Combine(_precompTargetPhysicalDir, HttpRuntime.BinDirectoryName);
            CopyCompiledAssembliesToDestinationBin(HttpRuntime.CodegenDirInternal, targetBinDir);
        }
 
        // Copy all the static files to the destination directory (if any).  We treat anything we
        // don't compile as a static file.  It's better to do this at the end of the precompilation, 
        // this way if any pages has errors (parse or compile), we never get to this step. 
        if (_precompTargetPhysicalDir != null) {
            CopyStaticFilesRecursive(appVdir, _precompTargetPhysicalDir, true /*topLevel*/); 
        }
    }

    // Create a small file that marks that app as being precompiled 
    private void CreatePrecompMarkerFile() {
 
        Debug.Assert(PrecompilingForDeployment); 

        Directory.CreateDirectory(_precompTargetPhysicalDir); 
        string precompMarkerFile = Path.Combine(_precompTargetPhysicalDir, precompMarkerFileName);

        using (StreamWriter writer = new StreamWriter(precompMarkerFile, false /*append*/, Encoding.UTF8)) {
            writer.Write("");
        }
    } 

    private static bool ReadPrecompMarkerFile(string appRoot, out bool updatable) { 
 
        updatable = false;
 
        // Get the full physical path to the precompilation market file
        string precompMarkerFile = Path.Combine(appRoot, precompMarkerFileName);

        // If the file doesn't exist at all, it's not a precompiled app 
        if (!File.Exists(precompMarkerFile))
            return false; 
 
        XmlDocument doc = new XmlDocument();
        try { 
            doc.Load(precompMarkerFile);
        }
        catch {
            // If we fail to read it for any reason, ignore it. 
            return false;
        } 
 
        // Get the root element, and make sure it's what we expect
        XmlNode root = doc.DocumentElement; 
        Debug.Assert(root != null && root.Name == "precompiledApp");
        if (root == null || root.Name != "precompiledApp")
            return false;
 
        // Check the updatable flag
        HandlerBase.GetAndRemoveBooleanAttribute(root, "updatable", ref updatable); 
 
        return true;
    } 

    /*
     * Are we precompiling the app for deployment (as opposed to in-place)
     */ 
    internal static bool PrecompilingForDeployment {
        get { 
            return (_theBuildManager._precompTargetPhysicalDir != null); 
        }
    } 

    internal static bool PrecompilingForUpdatableDeployment {
        get {
            // The updatebale mode only applies in deployment precompilation mode 
            if (!PrecompilingForDeployment)
                return false; 
 
            return (_theBuildManager._precompilationFlags & PrecompilationFlags.Updatable) != 0;
        } 
    }

    private static bool PrecompilingForCleanBuild {
        get { 
            return (_theBuildManager._precompilationFlags & PrecompilationFlags.Clean) != 0;
        } 
    } 

    internal static bool PrecompilingWithDebugInfo { 
        get {
            // The ForceDebug flag only applies in deployment precompilation mode
            if (!PrecompilingForDeployment)
                return false; 

            return (_theBuildManager._precompilationFlags & PrecompilationFlags.ForceDebug) != 0; 
        } 
    }
 
    internal static bool PrecompilingWithCodeAnalysisSymbol {
        get {
            return (_theBuildManager._precompilationFlags & PrecompilationFlags.CodeAnalysis) != 0;
        } 
    }
 
    private static bool CompileWithFixedAssemblyNames { 
        get {
            return (_theBuildManager._precompilationFlags & PrecompilationFlags.FixedNames) != 0; 
        }
    }

    internal static bool CompileWithAllowPartiallyTrustedCallersAttribute { 
        get {
            return (_theBuildManager._precompilationFlags & PrecompilationFlags.AllowPartiallyTrustedCallers) != 0; 
        } 
    }
 
    internal static bool CompileWithDelaySignAttribute {
        get {
            return (_theBuildManager._precompilationFlags & PrecompilationFlags.DelaySign) != 0;
        } 
    }
 
    internal static string StrongNameKeyFile { 
        get {
            return _theBuildManager._strongNameKeyFile; 
        }
    }

    internal static string StrongNameKeyContainer { 
        get {
            return _theBuildManager._strongNameKeyContainer; 
        } 
    }
 
    // If we're in the process of precompiling for updatable deployment, this returns
    // a writer to the target file specified by the virtual path.  This is used when the
    // deployed file needs to be different from the original (as is the case for aspx files).
    internal static TextWriter GetUpdatableDeploymentTargetWriter(VirtualPath virtualPath, Encoding fileEncoding) { 

        Debug.Assert(fileEncoding != null); 
 
        if (!PrecompilingForUpdatableDeployment)
            return null; 

        Debug.Assert(!virtualPath.IsRelative);

        string path = virtualPath.AppRelativeVirtualPathString; 

        // Skip the "~/" to be left with the relative path 
        path = path.Substring(2); 

        // Combine it with the precomp target dir to get the full path 
        string physicalPath = Path.Combine(_theBuildManager._precompTargetPhysicalDir, path);

        // Before trying to create the file, make sure the directory exists
        string physicalDir = Path.GetDirectoryName(physicalPath); 
        Directory.CreateDirectory(physicalDir);
 
        return new StreamWriter(physicalPath, false /*append*/, fileEncoding); 
    }
 
    private bool IsPrecompiledAppInternal {
        get {
            if (!_isPrecompiledAppComputed) {
                _isPrecompiledApp = ReadPrecompMarkerFile(HttpRuntime.AppDomainAppPathInternal, 
                    out _isUpdatablePrecompiledApp);
 
                _isPrecompiledAppComputed = true; 
            }
 
            return _isPrecompiledApp;
        }
    }
 
    internal static bool IsPrecompiledApp {
        get { 
            return _theBuildManager.IsPrecompiledAppInternal; 
        }
    } 

    private bool IsUpdatablePrecompiledAppInternal {
        get {
            return IsPrecompiledApp && _isUpdatablePrecompiledApp; 
        }
    } 
 
    internal static bool IsUpdatablePrecompiledApp {
        get { 
            return _theBuildManager.IsUpdatablePrecompiledAppInternal;
        }
    }
 
    private bool IsNonUpdatablePrecompiledApp {
        get { 
            return IsPrecompiledApp && !_isUpdatablePrecompiledApp; 
        }
    } 

    private void PrecompileWebDirectoriesRecursive(VirtualDirectory vdir, bool topLevel) {

        // Precompile the children directory 

        foreach (VirtualDirectory childVdir in vdir.Directories) { 
 
            if (topLevel && _excludedTopLevelDirectories.Contains(childVdir.Name))
                continue; 

            // Exclude the special FrontPage directory (VSWhidbey 116727, 518602)
            if (childVdir.Name == "_vti_cnf")
                continue; 

            PrecompileWebDirectoriesRecursive(childVdir, false /*topLevel*/); 
        } 

        // Precompile this directory 
        try {
            // Set a flag to remember that we're in the process of precompiling.  This
            // way, if BatchCompileWebDirectory ends up getting called again recursively
            // via CompileWebFile, we know that we cannot ignore errors. 
            _precompilingApp = true;
 
            if (IsBatchEnabledForDirectory(vdir.VirtualPathObject)) { 
                // batch everything if enabled
                BatchCompileWebDirectory(vdir, null, false /*ignoreErrors*/); 
            }
            else {
                // if batching is disabled, compile each web file individually.
                NonBatchDirectoryCompiler dirCompiler = new NonBatchDirectoryCompiler(vdir); 
                dirCompiler.Process();
            } 
        } 
        finally {
            // Always restore the flag to false when we're done. 
            _precompilingApp = false;
        }
    }
 
    private void PrecompileThemeDirectories() {
        string appPhysicalDir = Path.Combine(HttpRuntime.AppDomainAppPathInternal, HttpRuntime.ThemesDirectoryName); 
 
        if (Directory.Exists(appPhysicalDir)) {
            string[] themeDirs = Directory.GetDirectories(appPhysicalDir); 

            foreach (string themeDirPath in themeDirs) {
                string themeDirName = Path.GetFileName(themeDirPath);
                ThemeDirectoryCompiler.GetThemeBuildResultType(null /*context*/, themeDirName); 
            }
        } 
    } 

    /* 
     * Recursively copy all the static files from the source directory to the
     * target directory of the precompilation
     */
    private void CopyStaticFilesRecursive(VirtualDirectory sourceVdir, string destPhysicalDir, 
        bool topLevel) {
 
        // Make sure the target physical dir has no relation with the source.  It's important to 
        // check at every new directory, because IIS apps can have disconnected virtual sub dirs,
        // making an app root check insufficient (VSWhidbey 426251) 
        string sourcePhysicalDir = HostingEnvironment.MapPathInternal(sourceVdir.VirtualPath);
        VerifyUnrelatedSourceAndDest(sourcePhysicalDir, destPhysicalDir);

        bool directoryCreationAttempted = false; 

        foreach (VirtualFileBase child in sourceVdir.Children) { 
 
            string destPhysicalSubDir = Path.Combine(destPhysicalDir, child.Name);
 
            if (child.IsDirectory) {

                // Skip the special top level directories, since they never contain relevant
                // static files.  Note that we don't skip Themes, which does contain static files. 
                if (topLevel &&
                    (StringUtil.EqualsIgnoreCase(child.Name, HttpRuntime.CodeDirectoryName) || 
                    StringUtil.EqualsIgnoreCase(child.Name, HttpRuntime.ResourcesDirectoryName) || 
                    StringUtil.EqualsIgnoreCase(child.Name, HttpRuntime.WebRefDirectoryName))) {
 
                    continue;
                }

                // Also, skip the LocalResources directory at any level, except when precompiling 
                // for updatable deployment (in which case, we deploy the local resources file)
                if (!PrecompilingForUpdatableDeployment && StringUtil.EqualsIgnoreCase(child.Name, 
                    HttpRuntime.LocalResourcesDirectoryName)) { 
                    continue;
                } 

                CopyStaticFilesRecursive(child as VirtualDirectory, destPhysicalSubDir, false /*topLevel*/);
                continue;
            } 

            // Create the destination directory if needed 
            if (!directoryCreationAttempted) { 
                directoryCreationAttempted = true;
                Directory.CreateDirectory(destPhysicalDir); 
            }

            // Copy the file as appropriate based on its extension
            CopyPrecompiledFile(child as VirtualFile, destPhysicalSubDir); 
        }
    } 
 
    /*
     * Copy all the assemblies from the codegen dir into the bin directory of the 
     * target precompiled app.
     */
    private void CopyCompiledAssembliesToDestinationBin(string fromDir, string toDir) {
 
        bool createdDirectory = false;
 
        foreach (FileData fileData in FileEnumerator.Create(fromDir)) { 
            // Windows OS Bug 1981578
            // Create a new directory only if there is something in the directory. 
            if (!createdDirectory)
                Directory.CreateDirectory(toDir);
            createdDirectory = true;
 
            // Recurse on subdirectories.if they contain culture files
            if (fileData.IsDirectory) { 
 
                if (Util.IsCultureName(fileData.Name)) {
                    string fromSubDir = Path.Combine(fromDir, fileData.Name); 
                    string toSubDir = Path.Combine(toDir, fileData.Name);
                    CopyCompiledAssembliesToDestinationBin(fromSubDir, toSubDir);
                }
 
                continue;
            } 
 
            // Only process DLL's and PDB's
            string extension = Path.GetExtension(fileData.Name); 
            if (extension != ".dll" && extension != ".pdb")
                continue;

            string sourcePhysicalPath = Path.Combine(fromDir, fileData.Name); 
            string destPhysicalPath = Path.Combine(toDir, fileData.Name);
 
            // Copy the file to the destination 
            //
            File.Copy(sourcePhysicalPath, destPhysicalPath, true /*overwrite*/); 
        }
    }

    // Copy one file from the source app to the precompiled app 
    private void CopyPrecompiledFile(VirtualFile vfile, string destPhysicalPath) {
 
        bool createStub; 

        if (CompilationUtil.NeedToCopyFile(vfile.VirtualPathObject, PrecompilingForUpdatableDeployment, 
            out createStub)) {

            //
            string sourcePhysicalPath = HostingEnvironment.MapPathInternal(vfile.VirtualPath); 

            // The file could already exist with updatable precompilation, since we would create the modified file 
            // earlier during processing of a code beside page. 
            if (File.Exists(destPhysicalPath)) {
 
                // In that case, we still need to fix it up to insert the correct type string in the
                // inherits attribute (VSWhidbey 467936)

                // First, get the just-compiled BuildResult.  It should always exist 
                BuildResultCompiledType result = GetVPathBuildResult(null, vfile.VirtualPathObject,
                    true /*noBuild*/, false /*allowCrossApp*/) as BuildResultCompiledType; 
                Debug.Assert(result != null); 

                // VSWhidbey 527299. Need to use the same encoding of the original file to 
                // read and write to the new file.
                Encoding encoding = Util.GetEncodingFromConfigPath(vfile.VirtualPathObject);

                // Read in the file 
                string newAspxFile = Util.StringFromFile(destPhysicalPath, ref encoding);
 
                // Replace the placeholder token by the true type with the assembly 
                newAspxFile = newAspxFile.Replace(UpdatableInheritReplacementToken,
                    Util.GetAssemblyQualifiedTypeName(result.ResultType)); 

                // Write the modified file back with the correct inherits type string
                StreamWriter writer = new StreamWriter(destPhysicalPath, false /* append */, encoding);
                writer.Write(newAspxFile); 
                writer.Close();
            } 
            else { 
                // Just copy the file to the destination
                File.Copy(sourcePhysicalPath, destPhysicalPath, false /*overwrite*/); 
            }

            // If it has a readonly attribute, clear it on the destination (VSWhidbey 122359)
            Util.ClearReadOnlyAttribute(destPhysicalPath); 
        }
        else { 
            if (createStub) { 
                // Create the stub file, with a helpful static message
                StreamWriter writer = new StreamWriter(destPhysicalPath); 
                writer.Write(SR.GetString(SR.Precomp_stub_file));
                writer.Close();
            }
        } 
    }
 
    // Make sure the target physical dir has no relation with the source 
    internal static void VerifyUnrelatedSourceAndDest(string sourcePhysicalDir, string destPhysicalDir) {
 
        // Make sure they're normalized and end with a '\' before comparing (VSWhidbey 452554)
        sourcePhysicalDir = FileUtil.FixUpPhysicalDirectory(sourcePhysicalDir);
        destPhysicalDir = FileUtil.FixUpPhysicalDirectory(destPhysicalDir);
 
        if (StringUtil.StringStartsWithIgnoreCase(sourcePhysicalDir, destPhysicalDir) ||
            StringUtil.StringStartsWithIgnoreCase(destPhysicalDir, sourcePhysicalDir)) { 
            throw new HttpException(SR.GetString( 
                SR.Illegal_precomp_dir, destPhysicalDir, sourcePhysicalDir));
        } 
    }

    internal static void ReportDirectoryCompilationProgress(VirtualPath virtualDir) {
 
        // Nothing to do if there is no CBM callback
        if (CBMCallback == null) 
            return; 

        // Don't report anything if the directory doesn't exist 
        if (!virtualDir.DirectoryExists())
            return;

        string message = SR.GetString(SR.Directory_progress, virtualDir.VirtualPathString); 
        CBMCallback.ReportProgress(message);
    } 
 

    // 
    // Public methods
    //

 
    /// 
    ///     Compiles a file given its virtual path, using the appropriate BuildProvider (based 
    ///     on the file's extension).  The compiled type is returned. 
    ///     This methods performs both memory and disk caching of the compiled Type.
    ///  
    public static Type GetCompiledType(string virtualPath) {
        if (virtualPath == null) {
            throw new ArgumentNullException("virtualPath");
        } 

        return GetCompiledType(VirtualPath.Create(virtualPath)); 
    } 

    // This method is called by BuildManagerHost thru CBM 
    internal static Type GetCompiledType(VirtualPath virtualPath, ClientBuildManagerCallback callback) {
        // Remember the original setting
        bool skipTopLevelExceptions = SkipTopLevelCompilationExceptions;
        bool throwOnFirstParseError = ThrowOnFirstParseError; 

        try { 
            // Don't skip top level compilation exceptions even called by CBM. 
            SkipTopLevelCompilationExceptions = false;
 
            // Don't stop on the first parse error, process as many errors as possible.
            ThrowOnFirstParseError = false;

            _theBuildManager._cbmCallback = callback; 
            return GetCompiledType(virtualPath);
        } 
        finally { 
            _theBuildManager._cbmCallback = null;
 
            // Revert to original setting
            SkipTopLevelCompilationExceptions = skipTopLevelExceptions;

            ThrowOnFirstParseError = throwOnFirstParseError; 
        }
    } 
 
    internal static Type GetCompiledType(VirtualPath virtualPath) {
        ITypedWebObjectFactory factory = GetVirtualPathObjectFactory(virtualPath, 
            null /*context*/, false /*allowCrossApp*/, false /*noAssert*/);

        BuildResultCompiledType resultType = factory as BuildResultCompiledType;
        if (resultType == null) return null; 

        return resultType.ResultType; 
    } 

    /// Process a file based on its virtual path, and instantiate the result.  This API works for both 
    /// compiled and no compile pages.  requiredBaseType specifies a type from which the resulting
    /// object must derive.  If it doesn't, the API fails without instantiating the object.
    public static object CreateInstanceFromVirtualPath(string virtualPath, Type requiredBaseType) {
        VirtualPath virtualPathObject = VirtualPath.CreateNonRelative(virtualPath); 
        return CreateInstanceFromVirtualPath(virtualPathObject, requiredBaseType,
            null /*context*/, false /*allowCrossApp*/, false /*noAssert*/); 
    } 

    ///  
    ///     Process a file given its virtual path, using the appropriate BuildProvider (based
    ///     on the file's extension).  The result is then instantiated and returned.
    /// 
    internal static object CreateInstanceFromVirtualPath(VirtualPath virtualPath, 
        Type requiredBaseType, HttpContext context, bool allowCrossApp, bool noAssert) {
 
        ITypedWebObjectFactory objectFactory = GetVirtualPathObjectFactory(virtualPath, context, allowCrossApp, noAssert); 
        if (objectFactory == null) return null;
 
        // Make sure it has the required base type (VSWhidbey 516771)
        Util.CheckAssignableType(requiredBaseType, objectFactory.InstantiatedType);

        // impersonate client while executing page ctor (see ASURT 89712) 
        // (compilation is done while not impersonating client)
 
        Object instance; 
        using (new ClientImpersonationContext(context)) {
            instance = objectFactory.CreateInstance(); 
        }

        return instance;
    } 

 
    ///  
    ///     Process a file given its virtual path, using the appropriate BuildProvider (based
    ///     on the file's extension).  The ITypedWebObjectFactory is returned. 
    ///     This methods performs both memory and disk caching of the compiled Type.
    /// 
    private static ITypedWebObjectFactory GetVirtualPathObjectFactory(VirtualPath virtualPath,
        HttpContext context, bool allowCrossApp, bool noAssert) { 

        if (virtualPath == null) 
            throw new ArgumentNullException("virtualPath"); 

        // Throw here immediately if top level exception exists. 
        // This is because EnsureTopLevelFilesCompiled (where the exception is thrown)
        // might not be called.
        if (_theBuildManager._topLevelFileCompilationException != null) {
            _theBuildManager.ReportTopLevelCompilationException(); 
        }
 
        ITypedWebObjectFactory objectFactory; 
        BuildResult buildResult;
 
        // We need to assert here since there may be user code on the stack,
        // and code may demand UnmanagedCode permission.  But if we're in full trust,
        // or noAssert is true, skip the assert for perf reasons (VSWhidbey 146871, 500699)
        if (HttpRuntime.IsFullTrust || noAssert) { 
            buildResult = GetVPathBuildResultWithNoAssert(
                context, virtualPath, false /*noBuild*/, allowCrossApp, false /*allowBuildInPrecompile*/); 
        } 
        else {
            buildResult = GetVPathBuildResultWithAssert( 
                context, virtualPath, false /*noBuild*/, allowCrossApp, false /*allowBuildInPrecompile*/);
        }

        // DevDiv 67952 
        // The returned build result may not always be castable to ITypedWebObjectFactory.
        objectFactory = buildResult as ITypedWebObjectFactory; 
 
        return objectFactory;
    } 

    /// 
    ///     Compiles a file given its virtual path, using the appropriate BuildProvider (based
    ///     on the file's extension).  The compiled assembly is returned. 
    ///     This methods performs both memory and disk caching of the compiled assembly.
    ///  
    public static Assembly GetCompiledAssembly(string virtualPath) { 

        BuildResult result = GetVPathBuildResult(VirtualPath.Create(virtualPath)); 
        if (result == null) return null;

        BuildResultCompiledAssemblyBase resultAssembly = result as BuildResultCompiledAssemblyBase;
        if (resultAssembly == null) return null; 

        return resultAssembly.ResultAssembly; 
    } 

 
    /// 
    ///     Compiles a file given its virtual path, using the appropriate BuildProvider (based
    ///     on the file's extension).  If the BuildProvider chose to persist a custom
    ///     string, the string is returned. 
    ///     This methods performs both memory and disk caching.
    ///  
    public static string GetCompiledCustomString(string virtualPath) { 

        BuildResult result = GetVPathBuildResult(VirtualPath.Create(virtualPath)); 
        if (result == null) return null;

        BuildResultCustomString resultCustomString = result as BuildResultCustomString;
        if (resultCustomString == null) return null; 

        return resultCustomString.CustomString; 
    } 

    ///  
    ///     Returns the BuildDependencySet for the passed in virtualPath, assuming
    ///     that information is cached.  Otherwise, return null.
    /// 
    public static BuildDependencySet GetCachedBuildDependencySet( 
        HttpContext context, string virtualPath) {
 
        BuildResult result = GetVPathBuildResult(context, VirtualPath.Create(virtualPath), 
            true /*noBuild*/, false /*allowCrossApp*/);
 
        // If it's not cached, return null
        if (result == null)
            return null;
 
        // We found it in the cache.  Wrap it with a BuildDependencySet object.
        return new BuildDependencySet(result); 
    } 

    private Assembly ResolveAssembly(object sender, ResolveEventArgs e) { 

        if (_assemblyResolveMapping == null)
            return null;
 
        string name = e.Name;
        Assembly assembly = (Assembly)_assemblyResolveMapping[name]; 
 
        // Return the assembly if we have it in our mapping (VSWhidbey 276776)
        if (assembly != null) { 
            return assembly;
        }

        // Get the normalized assembly name from random name (VSWhidbey 380793) 
        String normalizedName = GetNormalizedCodeAssemblyName(name);
        if (normalizedName != null) { 
            return (Assembly)_assemblyResolveMapping[normalizedName]; 
        }
 
        return null;
    }

    internal static string GetNormalizedCodeAssemblyName(string assemblyName) { 
        // Return the main code assembly.
        if (assemblyName.StartsWith(CodeDirectoryAssemblyName, StringComparison.Ordinal)) { 
            return CodeDirectoryAssemblyName; 
        }
 
        // Check the sub code directories.
        CodeSubDirectoriesCollection codeSubDirectories = CompilationUtil.GetCodeSubDirectories();
        foreach (CodeSubDirectory directory in codeSubDirectories) {
            if (assemblyName.StartsWith(SubCodeDirectoryAssemblyNamePrefix + directory.AssemblyName + ".", StringComparison.Ordinal)) { 
                return directory.AssemblyName;
            } 
        } 

        return null; 
    }

    internal static string GetNormalizedTypeName(Type t) {
        string assemblyFullName = t.Assembly.FullName; 
        string normalizedCodeAssemblyName = GetNormalizedCodeAssemblyName(assemblyFullName);
        if (normalizedCodeAssemblyName == null) { 
            return t.AssemblyQualifiedName; 
        }
 
        string normalizedTypeName = t.FullName + ", " + normalizedCodeAssemblyName;
        return normalizedTypeName;
    }
} 

internal enum CompilationStage { 
    PreTopLevelFiles = 0,       // Before EnsureTopLevelFilesCompiled() is called 
    TopLevelFiles = 1,          // In EnsureTopLevelFilesCompiled() but before building global.asax
    GlobalAsax = 2,             // While building global.asax 
    BrowserCapabilities = 3,    // While building browserCap
    AfterTopLevelFiles = 4      // After EnsureTopLevelFilesCompiled() is called
}
 
internal class AssemblyReferenceInfo {
    internal Assembly Assembly; 
    internal int ReferenceIndex; 

    internal AssemblyReferenceInfo(int referenceIndex) { 
        ReferenceIndex = referenceIndex;
    }
}
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
                        

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