Code:
/ DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / Net / System / Net / _ConnectionGroup.cs / 1 / _ConnectionGroup.cs
//------------------------------------------------------------------------------ //// Copyright (c) Microsoft Corporation. All rights reserved. // //----------------------------------------------------------------------------- namespace System.Net { using System.Collections; using System.Diagnostics; using System.Threading; // // ConnectionGroup groups a list of connections within the ServerPoint context, // this used to keep context for things such as proxies or seperate clients. // internal class ConnectionGroup { // // Members // private const int DefaultConnectionListSize = 3; private ServicePoint m_ServicePoint; private string m_Name; private int m_ConnectionLimit; private ArrayList m_ConnectionList; private object m_Event; private Queue m_AuthenticationRequestQueue; internal bool m_AuthenticationGroup; private HttpAbortDelegate m_AbortDelegate; private bool m_NtlmNegGroup; private int m_IISVersion = -1; // // Constructors // internal ConnectionGroup(ServicePoint servicePoint, string connName) { m_ServicePoint = servicePoint; m_ConnectionLimit = servicePoint.ConnectionLimit; m_ConnectionList = new ArrayList(DefaultConnectionListSize); //it may grow beyond m_Name = MakeQueryStr(connName); m_AbortDelegate = new HttpAbortDelegate(Abort); GlobalLog.Print("ConnectionGroup::.ctor m_ConnectionLimit:" + m_ConnectionLimit.ToString()); } // // Accessors // internal ServicePoint ServicePoint { get { return m_ServicePoint; } } internal int CurrentConnections { get { return m_ConnectionList.Count; } } internal int ConnectionLimit { get { return m_ConnectionLimit; } set { m_ConnectionLimit = value; PruneExcesiveConnections(); GlobalLog.Print("ConnectionGroup::ConnectionLimit.set m_ConnectionLimit:" + m_ConnectionLimit.ToString()); } } private ManualResetEvent AsyncWaitHandle { get { if (m_Event == null) { // // lazy allocation of the event: // if this property is never accessed this object is never created // Interlocked.CompareExchange(ref m_Event, new ManualResetEvent(false), null); } ManualResetEvent castedEvent = (ManualResetEvent)m_Event; return castedEvent; } } private Queue AuthenticationRequestQueue { get { if (m_AuthenticationRequestQueue == null) { lock (m_ConnectionList) { if (m_AuthenticationRequestQueue == null) { m_AuthenticationRequestQueue = new Queue(); } } } return m_AuthenticationRequestQueue; } set { m_AuthenticationRequestQueue = value; } } // // Methods // internal static string MakeQueryStr(string connName) { return ((connName == null) ? "" : connName); } ////// internal void Associate(Connection connection) { lock (m_ConnectionList) { m_ConnectionList.Add(connection); } GlobalLog.Print("ConnectionGroup::Associate() Connection:" + connection.GetHashCode()); } ////// These methods are made available to the underlying Connection /// object so that we don't leak them because we're keeping a local /// reference in our m_ConnectionList. /// Called by the Connection's constructor /// ////// internal void Disassociate(Connection connection) { lock (m_ConnectionList) { m_ConnectionList.Remove(connection); } } ////// Used by the Connection's explicit finalizer (note this is /// not a destructor, since that's never calld unless we /// remove reference to the object from our internal list) /// ////// internal void ConnectionGoneIdle() { if (m_AuthenticationGroup) { lock (m_ConnectionList) { GlobalLog.Print("ConnectionGroup::ConnectionGoneIdle() setting the event"); AsyncWaitHandle.Set(); } } } ////// Called when a connection is idle and ready to process new requests /// ////// private bool Abort(HttpWebRequest request, WebException webException) { lock (m_ConnectionList) { AsyncWaitHandle.Set(); } return true; } ////// Causes an abort of any aborted requests waiting in the ConnectionGroup /// ////// private void PruneAbortedRequests() { lock (m_ConnectionList) { Queue updatedQueue = new Queue(); foreach(HttpWebRequest request in AuthenticationRequestQueue) { if (!request.Aborted) { updatedQueue.Enqueue(request); } } AuthenticationRequestQueue = updatedQueue; } } ////// Removes aborted requests from our queue. /// ////// private void PruneExcesiveConnections() { ArrayList connectionsToClose = new ArrayList(); lock(m_ConnectionList) { int connectionLimit = ConnectionLimit; if (CurrentConnections > connectionLimit) { int numberToPrune = CurrentConnections - connectionLimit; for (int i=0; i/// Removes extra connections that are found when reducing the connection limit /// ////// /// Forces all connections on the ConnectionGroup to not be KeepAlive. /// /// internal void DisableKeepAliveOnConnections() { // The timer thread is allowed to call this. (It doesn't call user code and doesn't block.) GlobalLog.ThreadContract(ThreadKinds.Unknown, ThreadKinds.SafeSources | ThreadKinds.Timer, "ConnectionGroup#" + ValidationHelper.HashString(this) + "::DisableKeepAliveOnConnections"); ArrayList connectionsToClose = new ArrayList(); lock (m_ConnectionList) { GlobalLog.Print("ConnectionGroup#" + ValidationHelper.HashString(this) + "::DisableKeepAliveOnConnections() Name = " + m_Name + ", Count:" + m_ConnectionList.Count); foreach (Connection currentConnection in m_ConnectionList) { // // For each Connection set KeepAlive to false // GlobalLog.Print("ConnectionGroup#" + ValidationHelper.HashString(this) + "::DisableKeepAliveOnConnections() setting KeepAlive to false Connection#" + ValidationHelper.HashString(currentConnection)); connectionsToClose.Add(currentConnection); } m_ConnectionList.Clear(); } foreach (Connection currentConnection in connectionsToClose) { currentConnection.CloseOnIdle(); } } ////// private Connection FindMatchingConnection(HttpWebRequest request, string connName, out Connection leastbusyConnection) { int minBusyCount = Int32.MaxValue; bool freeConnectionsAvail = false; leastbusyConnection = null; lock (m_ConnectionList) { // // go through the list of open connections to this service point and pick // the first empty one or, if none is empty, pick the least busy one. // minBusyCount = Int32.MaxValue; foreach (Connection currentConnection in m_ConnectionList) { GlobalLog.Print("ConnectionGroup::FindMatchingConnection currentConnection.BusyCount:" + currentConnection.BusyCount.ToString()); if (currentConnection.LockedRequest == request) { leastbusyConnection = currentConnection; return currentConnection; } GlobalLog.Print("ConnectionGroup::FindMatchingConnection: lockedRequest# " + ((currentConnection.LockedRequest == null) ? "null" : currentConnection.LockedRequest.GetHashCode().ToString())); if (currentConnection.BusyCount < minBusyCount && currentConnection.LockedRequest == null) { leastbusyConnection = currentConnection; minBusyCount = currentConnection.BusyCount; if (minBusyCount == 0) { freeConnectionsAvail = true; } } } // // If there is NOT a Connection free, then we allocate a new Connection // if (!freeConnectionsAvail && CurrentConnections < ConnectionLimit) { // // If we can create a new connection, then do it, // this may have complications in pipeling because // we may wish to optimize this case by actually // using existing connections, rather than creating new ones // // Note: this implicately results in a this.Associate being called. // GlobalLog.Print("ConnectionGroup::FindMatchingConnection [returning new Connection] CurrentConnections:" + CurrentConnections.ToString() + " ConnectionLimit:" + ConnectionLimit.ToString()); leastbusyConnection = new Connection(this); } } return null; // only if we have a locked Connection that matches can return non-null } ////// Attempts to match a request with a connection, if a connection is unassigned ie not locked with /// a request, then the least busy connections is returned in "leastbusyConnection." If the /// connection limit allows, and all connections are busy, a new one is allocated and returned. /// /// RETURNS: a Connection shown to match a previously locked Request/Connection (OTHERWISE) /// leasebusyConnection - will contain a newly allocated Connection or least Busy one /// suiteable for requests. /// /// NOTE: For Whidbey: try to integrate this code into FindConnection() /// ////// private Connection FindConnectionAuthenticationGroup(HttpWebRequest request, string connName) { Connection leastBusyConnection = null; GlobalLog.Print("ConnectionGroup::FindConnectionAuthenticationGroup [" + connName + "] for request#" + request.GetHashCode() +", m_ConnectionList.Count:" + m_ConnectionList.Count.ToString()); // // First try and find a free Connection (i.e. one not busy with Authentication handshake) // or try to find a Request that has already locked a specific Connection, // if a matching Connection is found, then we're done // lock (m_ConnectionList) { Connection matchingConnection; matchingConnection = FindMatchingConnection(request, connName, out leastBusyConnection); if (matchingConnection != null) { return matchingConnection; } if (AuthenticationRequestQueue.Count == 0) { if (leastBusyConnection != null) { if (request.LockConnection) { m_NtlmNegGroup = true; m_IISVersion = leastBusyConnection.IISVersion; } if(request.LockConnection || (m_NtlmNegGroup && !request.Pipelined && request.UnsafeOrProxyAuthenticatedConnectionSharing && m_IISVersion >= 6)){ GlobalLog.Print("Assigning New Locked Request#" + request.GetHashCode().ToString()); leastBusyConnection.LockedRequest = request; } return leastBusyConnection; } } else if (leastBusyConnection != null) { AsyncWaitHandle.Set(); } AuthenticationRequestQueue.Enqueue(request); } // // If all the Connections are busy, then we queue ourselves and need to wait. As soon as // one of the Connections are free, we grab the lock, and see if we find ourselves // at the head of the queue. If not, we loop backaround. // Care is taken to examine the request when we wakeup, in case the request is aborted. // while (true) { GlobalLog.Print("waiting"); request.AbortDelegate = m_AbortDelegate; if (!request.Aborted) AsyncWaitHandle.WaitOne(); GlobalLog.Print("wait up"); lock(m_ConnectionList) { if (request.Aborted) { PruneAbortedRequests(); // Note that request is not on any connection and it will not be submitted return null; } FindMatchingConnection(request, connName, out leastBusyConnection); if (AuthenticationRequestQueue.Peek() == request) { GlobalLog.Print("dequeue"); AuthenticationRequestQueue.Dequeue(); if (leastBusyConnection != null) { if (request.LockConnection) { m_NtlmNegGroup = true; m_IISVersion = leastBusyConnection.IISVersion; } if(request.LockConnection || (m_NtlmNegGroup && !request.Pipelined && request.UnsafeOrProxyAuthenticatedConnectionSharing && m_IISVersion >= 6)){ leastBusyConnection.LockedRequest = request; } return leastBusyConnection; } AuthenticationRequestQueue.Enqueue(request); } if (leastBusyConnection == null) { AsyncWaitHandle.Reset(); } } } } ////// Used by the ServicePoint to find a free or new Connection /// for use in making Requests, this is done with the cavet, /// that once a Connection is "locked" it can only be used /// by a specific request. /// /// NOTE: For Whidbey: try to integrate this code into FindConnection() /// ////// internal Connection FindConnection(HttpWebRequest request, string connName) { Connection leastbusyConnection = null; Connection newConnection = null; bool freeConnectionsAvail = false; if (m_AuthenticationGroup || request.LockConnection) { m_AuthenticationGroup = true; return FindConnectionAuthenticationGroup(request, connName); } GlobalLog.Print("ConnectionGroup::FindConnection [" + connName + "] m_ConnectionList.Count:" + m_ConnectionList.Count.ToString()); lock (m_ConnectionList) { // // go through the list of open connections to this service point and pick // the first empty one or, if none is empty, pick the least busy one. // int minBusyCount = Int32.MaxValue; foreach (Connection currentConnection in m_ConnectionList) { GlobalLog.Print("ConnectionGroup::FindConnection currentConnection.BusyCount:" + currentConnection.BusyCount.ToString()); if (currentConnection.BusyCount < minBusyCount) { leastbusyConnection = currentConnection; minBusyCount = currentConnection.BusyCount; if (minBusyCount == 0) { freeConnectionsAvail = true; break; } } } // // If there is NOT a Connection free, then we allocate a new Connection // if (!freeConnectionsAvail && CurrentConnections < ConnectionLimit) { // // If we can create a new connection, then do it, // this may have complications in pipeling because // we may wish to optimize this case by actually // using existing connections, rather than creating new ones // // Note: this implicately results in a this.Associate being called. // GlobalLog.Print("ConnectionGroup::FindConnection [returning new Connection] freeConnectionsAvail:" + freeConnectionsAvail.ToString() + " CurrentConnections:" + CurrentConnections.ToString() + " ConnectionLimit:" + ConnectionLimit.ToString()); newConnection = new Connection(this); } else { // // All connections are busy, use the least busy one // GlobalLog.Print("ConnectionGroup::FindConnection [returning leastbusyConnection] freeConnectionsAvail:" + freeConnectionsAvail.ToString() + " CurrentConnections:" + CurrentConnections.ToString() + " ConnectionLimit:" + ConnectionLimit.ToString()); GlobalLog.Assert(leastbusyConnection != null, "Connect.leastbusyConnection != null|All connections have BusyCount equal to Int32.MaxValue."); newConnection = leastbusyConnection; } } return newConnection; } [System.Diagnostics.Conditional("DEBUG")] internal void Debug(int requestHash) { foreach(Connection connection in m_ConnectionList) { connection.Debug(requestHash); } } } }/// Used by the ServicePoint to find a free or new Connection /// for use in making Requests. Under NTLM and Negotiate requests, /// this function depricates itself and switches the object over to /// using a new code path (see FindConnectionAuthenticationGroup). /// ///
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