DbConnectionInternal.cs source code in C# .NET

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/ DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / Data / System / Data / ProviderBase / DbConnectionInternal.cs / 2 / DbConnectionInternal.cs

                            //------------------------------------------------------------------------------ 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// [....] 
//-----------------------------------------------------------------------------
 
namespace System.Data.ProviderBase { 

    using System; 
    using System.ComponentModel;
    using System.Data;
    using System.Data.Common;
    using System.Diagnostics; 
    using System.Globalization;
    using System.Runtime.ConstrainedExecution; 
    using System.Runtime.InteropServices; 
    using System.Runtime.InteropServices.ComTypes;
    using System.Security; 
    using System.Security.Permissions;
    using System.Threading;
    using SysTx = System.Transactions;
 
    internal abstract class DbConnectionInternal { // V1.1.3300
        private static int _objectTypeCount; 
        internal readonly int _objectID = Interlocked.Increment(ref _objectTypeCount); 

        internal static readonly StateChangeEventArgs StateChangeClosed = new StateChangeEventArgs(ConnectionState.Open, ConnectionState.Closed); 
        internal static readonly StateChangeEventArgs StateChangeOpen   = new StateChangeEventArgs(ConnectionState.Closed, ConnectionState.Open);

        private readonly bool            _allowSetConnectionString;
        private readonly bool            _hidePassword; 
        private readonly ConnectionState _state;
 
        private readonly WeakReference   _owningObject = new WeakReference(null, false);  // [usage must be thread safe] the owning object, when not in the pool. (both Pooled and Non-Pooled connections) 

        // should only be used by DbConnectionPool.DbConnectionInternalListStack.Synchronized(Push|Pop) 
        private DbConnectionInternal _nextPooledObject;
        internal DbConnectionInternal NextPooledObject {
            get { return _nextPooledObject; }
            set { _nextPooledObject = value; } 
        }
 
        private DbConnectionPool         _connectionPool;           // the pooler that the connection came from (Pooled connections only) 
        private DbConnectionPoolCounters _performanceCounters;      // the performance counters we're supposed to update
        private DbReferenceCollection    _referenceCollection;      // collection of objects that we need to notify in some way when we're being deactivated 
        private int                      _pooledCount;              // [usage must be thread safe] the number of times this object has been pushed into the pool less the number of times it's been popped (0 != inPool)

        private bool                     _connectionIsDoomed;       // true when the connection should no longer be used.
        private bool                     _cannotBePooled;           // true when the connection should no longer be pooled. 
        private bool                     _isInStasis;
 
        private DateTime                 _createTime;               // when the connection was created. 

        private SysTx.Transaction        _enlistedTransaction;      // [usage must be thread-safe] the transaction that we're enlisted in, either manually or automatically 

#if DEBUG
        private int                      _activateCount;            // debug only counter to verify activate/deactivates are in sync.
#endif //DEBUG 

        protected DbConnectionInternal() : this(ConnectionState.Open, true, false) { // V1.1.3300 
        } 

        // Constructor for internal connections 
        internal DbConnectionInternal(ConnectionState state, bool hidePassword, bool allowSetConnectionString) {
            _allowSetConnectionString = allowSetConnectionString;
            _hidePassword = hidePassword;
            _state = state; 
        }
 
        internal bool AllowSetConnectionString { 
            get {
                return _allowSetConnectionString; 
            }
        }

        internal bool CanBePooled { 
            get {
                bool flag = (!_connectionIsDoomed && !_cannotBePooled && !_owningObject.IsAlive); 
                return flag; 
            }
        } 

        protected internal SysTx.Transaction EnlistedTransaction {
            get {
                return _enlistedTransaction; 
            }
            set { 
                if (((null == _enlistedTransaction) && (null != value)) 
                    || ((null != _enlistedTransaction) && !_enlistedTransaction.Equals(value))) {  // WebData 20000024
 
                    // Pay attention to the order here:
                    // 1) defect from any notifications
                    // 2) replace the transaction
                    // 3) re-enlist in notifications for the new transaction 

                    // 
 

                    SysTx.Transaction valueClone = null; 
                    SysTx.Transaction previousTransactionClone = null;
                    try {
                        if (null != value) {
                            valueClone = value.Clone(); 
                        }
 
                        // NOTE: rather than take locks around several potential round- 
                        // trips to the server, and/or virtual function calls, we simply
                        // presume that you aren't doing something illegal from multiple 
                        // threads, and check once we get around to finalizing things
                        // inside a lock.

                        lock(this) { 
                            // NOTE: There is still a race condition here, when we are
                            // called from EnlistTransaction (which cannot re-enlist) 
                            // instead of EnlistDistributedTransaction (which can), 
                            // however this should have been handled by the outer
                            // connection which checks to ensure that it's OK.  The 
                            // only case where we have the race condition is multiple
                            // concurrent enlist requests to the same connection, which
                            // is a bit out of line with something we should have to
                            // support. 

                            previousTransactionClone = _enlistedTransaction; 
                            _enlistedTransaction = valueClone; 
                            value = valueClone;
                            valueClone = null; // we've stored it, don't dispose it. 
                        }
                    }
                    finally {
                        // we really need to dispose our clones; they may have 
                        // native resources and GC may not happen soon enough.
                        if (null != previousTransactionClone) { 
                            previousTransactionClone.Dispose(); 
                        }
                        if (null != valueClone) { 
                            valueClone.Dispose();
                        }
                    }
 
                    // I don't believe that we need to lock to protect the actual
                    // enlistment in the transaction; it would only protect us 
                    // against multiple concurrent calls to enlist, which really 
                    // isn't supported anyway.
 
                    if (null != value) {
                        if (Bid.IsOn(DbConnectionPool.PoolerTracePoints)) {
                            int x = value.GetHashCode();
                            Bid.PoolerTrace(" %d#, Transaction %d#, Enlisting.\n", ObjectID, x); 
                        }
                        TransactionOutcomeEnlist(value); 
                    } 
                }
            } 
        }

        // Is this connection in stasis, waiting for transaction to end before returning to pool?
        internal bool IsTxRootWaitingForTxEnd { 
            get {
                return _isInStasis; 
            } 
        }
 
        virtual internal bool RequireExplicitTransactionUnbind {
            get {
                return false;       // override to add explicit unbind requirement
            } 
        }
 
        // Is this a connection that must be put in stasis (or is already in stasis) pending the end of it's transaction? 
        virtual protected internal bool IsNonPoolableTransactionRoot {
            get { 
                return false; // if you want to have delegated transactions that are non-poolable, you better override this...
            }
        }
 
        virtual internal bool IsTransactionRoot {
            get { 
                return false; // if you want to have delegated transactions, you better override this... 
            }
        } 

        public bool HasEnlistedTransaction {
            get {
                return (null != EnlistedTransaction);   // NOTE: race condition in EnlistedTransaction applies here too. 
            }
        } 
 
        protected internal bool IsConnectionDoomed {
            get { 
                return _connectionIsDoomed;
            }
        }
 
        internal bool IsEmancipated {
            get { 
                // NOTE: There are race conditions between PrePush, PostPop and this 
                //       property getter -- only use this while this object is locked;
                //       (DbConnectionPool.Clear and ReclaimEmancipatedObjects 
                //       do this for us)

                // Remember how this works (I keep getting confused...)
                // 
                //    _pooledCount is incremented when the connection is pushed into the pool
                //    _pooledCount is decremented when the connection is popped from the pool 
                //    _pooledCount is set to -1 when the connection is not pooled (just in case...) 
                //
                // That means that: 
                //
                //    _pooledCount > 1    connection is in the pool multiple times (this is a serious bug...)
                //    _pooledCount == 1   connection is in the pool
                //    _pooledCount == 0   connection is out of the pool 
                //    _pooledCount == -1  connection is not a pooled connection; we shouldn't be here for non-pooled connections.
                //    _pooledCount < -1   connection out of the pool multiple times (not sure how this could happen...) 
                // 
                // Now, our job is to return TRUE when the connection is out
                // of the pool and it's owning object is no longer around to 
                // return it.

                bool value = !IsTxRootWaitingForTxEnd && (_pooledCount < 1) && !_owningObject.IsAlive;
                return value; 
            }
        } 
 
        internal int ObjectID {
            get { 
                return _objectID;
            }
        }
 
        protected internal object Owner {
            // We use a weak reference to the owning object so we can identify when 
            // it has been garbage collected without thowing exceptions. 
            get {
                return _owningObject.Target; 
            }
        }

        internal DbConnectionPool Pool { 
            get {
                return _connectionPool; 
            } 
        }
 
        protected DbConnectionPoolCounters PerformanceCounters {
            get {
                return _performanceCounters;
            } 
        }
 
        virtual protected bool ReadyToPrepareTransaction { 
            get {
                return true; 
            }
        }

        protected internal DbReferenceCollection ReferenceCollection { 
            get {
                return _referenceCollection; 
            } 
        }
 
        abstract public string ServerVersion {
            get;
        }
 
        // this should be abstract but untill it is added to all the providers virtual will have to do [....]
        virtual public string ServerVersionNormalized { 
            get{ 
                throw ADP.NotSupported();
            } 
        }

        public bool ShouldHidePassword {
            get { 
                return _hidePassword;
            } 
        } 

        public ConnectionState State { 
            get {
                return _state;
            }
        } 

        abstract protected void Activate(SysTx.Transaction transaction); 
 
        internal void ActivateConnection(SysTx.Transaction transaction) {
            // Internal method called from the connection pooler so we don't expose 
            // the Activate method publicly.

            Bid.PoolerTrace(" %d#, Activating\n", ObjectID);
#if DEBUG 
            int activateCount = Interlocked.Increment(ref _activateCount);
            Debug.Assert(1 == activateCount, "activated multiple times?"); 
#endif // DEBUG 

            Activate(transaction); 

            PerformanceCounters.NumberOfActiveConnections.Increment();
        }
 
        internal void AddWeakReference(object value, int tag) {
            if (null == _referenceCollection) { 
                _referenceCollection = CreateReferenceCollection(); 
                if (null == _referenceCollection) {
                    throw ADP.InternalError(ADP.InternalErrorCode.CreateReferenceCollectionReturnedNull); 
                }
            }
            _referenceCollection.Add(value, tag);
        } 

        abstract public DbTransaction BeginTransaction(IsolationLevel il); 
 
        virtual public void ChangeDatabase(string value) {
            throw ADP.MethodNotImplemented("ChangeDatabase"); 
        }

        internal virtual void CloseConnection(DbConnection owningObject, DbConnectionFactory connectionFactory) {
            // The implementation here is the implementation required for the 
            // "open" internal connections, since our own private "closed"
            // singleton internal connection objects override this method to 
            // prevent anything funny from happening (like disposing themselves 
            // or putting them into a connection pool)
            // 
            // Derived class should override DbConnectionInternal.Deactivate and DbConnectionInternal.Dispose
            // for cleaning up after DbConnection.Close
            //     protected override void Deactivate() { // override DbConnectionInternal.Close
            //         // do derived class connection deactivation for both pooled & non-pooled connections 
            //     }
            //     public override void Dispose() { // override DbConnectionInternal.Close 
            //         // do derived class cleanup 
            //         base.Dispose();
            //     } 
            //
            // overriding DbConnection.Close is also possible, but must provider for their own synchronization
            //     public override void Close() { // override DbConnection.Close
            //         base.Close(); 
            //         // do derived class outer connection for both pooled & non-pooled connections
            //         // user must do their own synchronization here 
            //     } 
            //
            //     if the DbConnectionInternal derived class needs to close the connection it should 
            //     delegate to the DbConnection if one exists or directly call dispose
            //         DbConnection owningObject = (DbConnection)Owner;
            //         if (null != owningObject) {
            //             owningObject.Close(); // force the closed state on the outer object. 
            //         }
            //         else { 
            //             Dispose(); 
            //         }
            // 
            ////////////////////////////////////////////////////////////////
            // DON'T MESS WITH THIS CODE UNLESS YOU KNOW WHAT YOU'RE DOING!
            ////////////////////////////////////////////////////////////////
            Debug.Assert(null != owningObject, "null owningObject"); 
            Debug.Assert(null != connectionFactory, "null connectionFactory");
            Debug.Assert(owningObject == Owner, "Close with different owner"); 
            Debug.Assert(connectionFactory.GetInnerConnection(owningObject) == this || this.IsConnectionDoomed, "Close of not this"); 

            Bid.PoolerTrace(" %d# Closing.\n", ObjectID); 

            // if an exception occurs after the state change but before the try block
            // the connection will be stuck in OpenBusy state.  The commented out try-catch
            // block doesn't really help because a ThreadAbort during the finally block 
            // would just refert the connection to a bad state.
            // Open->Closed: guarantee internal connection is returned to correct pool 
            if (connectionFactory.SetInnerConnectionFrom(owningObject, DbConnectionOpenBusy.SingletonInstance, this)) { 
                try {
 
                    DbConnectionPool connectionPool = Pool;

                    // Detach from enlisted transactions that are no longer active on close
                    SysTx.Transaction enlistedTransaction = EnlistedTransaction; 
                    if (null != enlistedTransaction && SysTx.TransactionStatus.Active != enlistedTransaction.TransactionInformation.Status) {
                        DetachTransaction(enlistedTransaction); 
                    } 

                    // The singleton closed classes won't have owners and 
                    // connection pools, and we won't want to put them back
                    // into the pool.
                    if (null != connectionPool) {
                        connectionPool.PutObject(this, owningObject);   // PutObject calls Deactivate for us... 
                        // NOTE: Before we leave the PutObject call, another
                        // thread may have already popped the connection from 
                        // the pool, so don't expect to be able to verify it. 
                    }
                    else { 
                        Deactivate();   // ensure we de-activate non-pooled connections, or the data readers and transactions may not get cleaned up...

                        PerformanceCounters.HardDisconnectsPerSecond.Increment();
 
                        // To prevent an endless recursion, we need to clear
                        // the owning object before we call dispose so that 
                        // we can't get here a second time... Ordinarily, I 
                        // would call setting the owner to null a hack, but
                        // this is safe since we're about to dispose the 
                        // object and it won't have an owner after that for
                        // certain.
                        _owningObject.Target = null;
 
                        if (IsTransactionRoot) {
                            SetInStasis(); 
                        } 
                        else {
                            PerformanceCounters.NumberOfNonPooledConnections.Decrement(); 
#if !ORACLE
                            if (this.GetType() != typeof(System.Data.SqlClient.SqlInternalConnectionSmi))
#endif
                            { 
                                Dispose();
                            } 
                        } 
                    }
                } 
                finally {
                    // if a ThreadAbort puts us here then its possible the outer connection will not reference
                    // this and this will be orphaned, not reclaimed by object pool until outer connection goes out of scope.
                    connectionFactory.SetInnerConnectionEvent(owningObject, DbConnectionClosedPreviouslyOpened.SingletonInstance); 
                }
            } 
        } 

        virtual protected DbReferenceCollection CreateReferenceCollection() { 
            throw ADP.InternalError(ADP.InternalErrorCode.AttemptingToConstructReferenceCollectionOnStaticObject);
        }

        abstract protected void Deactivate(); 

        internal void DeactivateConnection() { 
            // Internal method called from the connection pooler so we don't expose 
            // the Deactivate method publicly.
 
            Bid.PoolerTrace(" %d#, Deactivating\n", ObjectID);
#if DEBUG
            int activateCount = Interlocked.Decrement(ref _activateCount);
            Debug.Assert(0 == activateCount, "activated multiple times?"); 
#endif // DEBUG
 
            PerformanceCounters.NumberOfActiveConnections.Decrement(); 

            if (!_connectionIsDoomed && Pool.UseLoadBalancing) { 
                // If we're not already doomed, check the connection's lifetime and
                // doom it if it's lifetime has elapsed.

                DateTime now = DateTime.UtcNow;  // WebData 111116 
                if ((now.Ticks - _createTime.Ticks) > Pool.LoadBalanceTimeout.Ticks) {
                    DoNotPoolThisConnection(); 
                } 
            }
            Deactivate(); 
        }

        virtual internal void DelegatedTransactionEnded() {
            // Called by System.Transactions when the delegated transaction has 
            // completed.  We need to make closed connections that are in stasis
            // available again, or disposed closed/leaked non-pooled connections. 
 
            // IMPORTANT NOTE: You must have taken a lock on the object before
            // you call this method to prevent race conditions with Clear and 
            // ReclaimEmancipatedObjects.

            Bid.Trace(" %d#, Delegated Transaction Completed.\n", ObjectID);
 
            if (1 == _pooledCount) {
                // When _pooledCount is 1, it indicates a closed, pooled, 
                // connection so it is ready to put back into the pool for 
                // general use.
 
                TerminateStasis(true);

                Deactivate(); // call it one more time just in case
 
                DbConnectionPool pool = Pool;
 
                if (null == pool) { 
                    throw ADP.InternalError(ADP.InternalErrorCode.PooledObjectWithoutPool);      // pooled connection does not have a pool
                } 
                pool.PutObjectFromTransactedPool(this);
            }
            else if (-1 == _pooledCount && !_owningObject.IsAlive) {
                // When _pooledCount is -1 and the owning object no longer exists, 
                // it indicates a closed (or leaked), non-pooled connection so
                // it is safe to dispose. 
 
                TerminateStasis(false);
 
                Deactivate(); // call it one more time just in case

                // it's a non-pooled connection, we need to dispose of it
                // once and for all, or the server will have fits about us 
                // leaving connections open until the client-side GC kicks
                // in. 
                PerformanceCounters.NumberOfNonPooledConnections.Decrement(); 
                Dispose();
            } 
            // When _pooledCount is 0, the connection is a pooled connection
            // that is either open (if the owning object is alive) or leaked (if
            // the owning object is not alive)  In either case, we can't muck
            // with the connection here. 
        }
 
        public virtual void Dispose() { 
            _connectionPool = null;
            _performanceCounters = null; 
            _connectionIsDoomed = true;
            _enlistedTransaction = null; //
        }
 
        protected internal void DoNotPoolThisConnection() {
            _cannotBePooled = true; 
            Bid.PoolerTrace(" %d#, Marking pooled object as non-poolable so it will be disposed\n", ObjectID); 
        }
 
        /// Ensure that this connection cannot be put back into the pool.
        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
        protected internal void DoomThisConnection() {
            _connectionIsDoomed = true; 
            Bid.PoolerTrace(" %d#, Dooming\n", ObjectID);
        } 
 
        abstract public void EnlistTransaction(SysTx.Transaction transaction);
 
        virtual protected internal DataTable GetSchema(DbConnectionFactory factory, DbConnectionPoolGroup poolGroup, DbConnection outerConnection, string collectionName, string[] restrictions){
            Debug.Assert(outerConnection != null,"outerConnection may not be null.");

            DbMetaDataFactory metaDataFactory = factory.GetMetaDataFactory(poolGroup, this); 
            Debug.Assert(metaDataFactory != null,"metaDataFactory may not be null.");
 
            return metaDataFactory.GetSchema(outerConnection, collectionName,restrictions); 
        }
 
        internal void MakeNonPooledObject(object owningObject, DbConnectionPoolCounters performanceCounters) {
            // Used by DbConnectionFactory to indicate that this object IS NOT part of
            // a connection pool.
 
            _connectionPool = null;
            _performanceCounters = performanceCounters; 
            _owningObject.Target = owningObject; 
            _pooledCount = -1;
        } 

        internal void MakePooledConnection(DbConnectionPool connectionPool) {
            // Used by DbConnectionFactory to indicate that this object IS part of
            // a connection pool. 

            // 
            _createTime = DateTime.UtcNow; // WebData 111116 

            _connectionPool = connectionPool; 
            _performanceCounters = connectionPool.PerformanceCounters;
        }

        internal void NotifyWeakReference(int message) { 
            DbReferenceCollection referenceCollection = ReferenceCollection;
            if (null != referenceCollection) { 
                referenceCollection.Notify(message); 
            }
        } 

        /// The default implementation is for the open connection objects, and
        /// it simply throws.  Our private closed-state connection objects
        /// override this and do the correct thing. 
        // User code should either override DbConnectionInternal.Activate when it comes out of the pool
        // or override DbConnectionFactory.CreateConnection when the connection is created for non-pooled connections 
        internal virtual void OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory) { 
            throw ADP.ConnectionAlreadyOpen(State);
        } 

        internal void PrePush(object expectedOwner) {
            // Called by DbConnectionPool when we're about to be put into it's pool, we
            // take this opportunity to ensure ownership and pool counts are legit. 

            // IMPORTANT NOTE: You must have taken a lock on the object before 
            // you call this method to prevent race conditions with Clear and 
            // ReclaimEmancipatedObjects.
 
            //3 // The following tests are retail assertions of things we can't allow to happen.
            if (null == expectedOwner) {
                if (null != _owningObject.Target) {
                    throw ADP.InternalError(ADP.InternalErrorCode.UnpooledObjectHasOwner);      // new unpooled object has an owner 
                }
            } 
            else if (_owningObject.Target != expectedOwner) { 
                throw ADP.InternalError(ADP.InternalErrorCode.UnpooledObjectHasWrongOwner); // unpooled object has incorrect owner
            } 
            if (0 != _pooledCount) {
                throw ADP.InternalError(ADP.InternalErrorCode.PushingObjectSecondTime);         // pushing object onto stack a second time
            }
            if (Bid.IsOn(DbConnectionPool.PoolerTracePoints)) { 
                //DbConnection x = (expectedOwner as DbConnection);
                Bid.PoolerTrace(" %d#, Preparing to push into pool, owning connection %d#, pooledCount=%d\n", ObjectID, 0, _pooledCount); 
            } 
            _pooledCount++;
            _owningObject.Target = null; // NOTE: doing this and checking for InternalError.PooledObjectHasOwner degrades the close by 2% 
        }

        internal void PostPop(object newOwner) {
            // Called by DbConnectionPool right after it pulls this from it's pool, we 
            // take this opportunity to ensure ownership and pool counts are legit.
 
            Debug.Assert(!IsEmancipated,"pooled object not in pool"); 

            // 



 

 
            // IMPORTANT NOTE: You must have taken a lock on the object before 
            // you call this method to prevent race conditions with Clear and
            // ReclaimEmancipatedObjects. 

            if (null != _owningObject.Target) {
                throw ADP.InternalError(ADP.InternalErrorCode.PooledObjectHasOwner);        // pooled connection already has an owner!
            } 
            _owningObject.Target = newOwner;
            _pooledCount--; 
            if (Bid.IsOn(DbConnectionPool.PoolerTracePoints)) { 
                //DbConnection x = (newOwner as DbConnection);
                Bid.PoolerTrace(" %d#, Preparing to pop from pool,  owning connection %d#, pooledCount=%d\n", ObjectID, 0, _pooledCount); 
            }
            //3 // The following tests are retail assertions of things we can't allow to happen.
            if (null != Pool) {
                if (0 != _pooledCount) { 
                    throw ADP.InternalError(ADP.InternalErrorCode.PooledObjectInPoolMoreThanOnce);  // popping object off stack with multiple pooledCount
                } 
            } 
            else if (-1 != _pooledCount) {
                throw ADP.InternalError(ADP.InternalErrorCode.NonPooledObjectUsedMoreThanOnce); // popping object off stack with multiple pooledCount 
            }
        }

        internal void RemoveWeakReference(object value) { 
            DbReferenceCollection referenceCollection = ReferenceCollection;
            if (null != referenceCollection) { 
                referenceCollection.Remove(value); 
            }
        } 

        // Cleanup connection's transaction-specific structures (currently used by Delegated transaction).
        //  This is a separate method because cleanup can be triggered in multiple ways for a delegated
        //  transaction. 
        virtual protected void CleanupTransactionOnCompletion(SysTx.Transaction transaction) {
        } 
 
        // Detach transaction from connection.
        internal void DetachTransaction(SysTx.Transaction transaction) { 
            Bid.Trace(" %d#, Transaction Completed. (pooledCount=%d)\n", ObjectID, _pooledCount);

            // potentially a multi-threaded event, so lock the connection to make sure we don't enlist in a new
            // transaction between compare and assignment. No need to short circuit outside of lock, since failed comparisons should 
            // be the exception, not the rule.
            lock (this) { 
                // Detach if detach-on-end behavior, or if outer connection was closed 
                DbConnection owner = (DbConnection)Owner;
                if (!RequireExplicitTransactionUnbind || null == owner) { 
                    if (_enlistedTransaction != null && transaction.Equals(_enlistedTransaction)) {
                        EnlistedTransaction = null;

                        if (IsTxRootWaitingForTxEnd) { 
                            DelegatedTransactionEnded();
                        } 
                    } 
                }
            } 
        }

        // Handle transaction detach, pool cleanup and other post-transaction cleanup tasks associated with
        internal void CleanupConnectionOnTransactionCompletion(SysTx.Transaction transaction) { 
            DetachTransaction(transaction);
 
            DbConnectionPool pool = Pool; 
            if (null != pool) {
                pool.TransactionEnded(transaction, this); 
            }
        }

        void TransactionCompletedEvent(object sender, SysTx.TransactionEventArgs e) { 
            SysTx.Transaction transaction = e.Transaction;
 
            Bid.Trace(" %d#, Transaction Completed. (pooledCount=%d)\n", ObjectID, _pooledCount); 

            CleanupTransactionOnCompletion(transaction); 

            CleanupConnectionOnTransactionCompletion(transaction);
        }
 

        // 
        [SecurityPermission(SecurityAction.Assert, Flags=SecurityPermissionFlag.UnmanagedCode)] 
        private void TransactionOutcomeEnlist(SysTx.Transaction transaction) {
            transaction.TransactionCompleted += new SysTx.TransactionCompletedEventHandler(TransactionCompletedEvent); 
        }

        internal void SetInStasis() {
            _isInStasis = true; 
            Bid.PoolerTrace(" %d#, Non-Pooled Connection has Delegated Transaction, waiting to Dispose.\n", ObjectID);
            PerformanceCounters.NumberOfStasisConnections.Increment(); 
        } 

        private void TerminateStasis(bool returningToPool) { 
            if (returningToPool) {
                Bid.PoolerTrace(" %d#, Delegated Transaction has ended, connection is closed.  Returning to general pool.\n", ObjectID);
            }
            else { 
                Bid.PoolerTrace(" %d#, Delegated Transaction has ended, connection is closed/leaked.  Disposing.\n", ObjectID);
            } 
            PerformanceCounters.NumberOfStasisConnections.Decrement(); 
            _isInStasis = false;
        } 
    }
}

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

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