_OverlappedAsyncResult.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Net / System / Net / Sockets / _OverlappedAsyncResult.cs / 1305376 / _OverlappedAsyncResult.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Net.Sockets { 
    using System; 
    using System.Net;
    using System.Runtime.InteropServices; 
    using System.Threading;
    using Microsoft.Win32;
    using System.Collections.Generic;
 
    //
    //  OverlappedAsyncResult - used to take care of storage for async Socket operation 
    //   from the BeginSend, BeginSendTo, BeginReceive, BeginReceiveFrom calls. 
    //
    internal class OverlappedAsyncResult: BaseOverlappedAsyncResult { 

        //
        // internal class members
        // 

        private SocketAddress  m_SocketAddress; 
        private SocketAddress  m_SocketAddressOriginal; // needed for partial BeginReceiveFrom/EndReceiveFrom completion 

        // These two are used only as alternatives 
        internal WSABuffer    m_SingleBuffer;
        internal WSABuffer[]  m_WSABuffers;

        // 
        // the following two will be used only on WinNT to enable completion ports
        // 
        // 
        // Constructor. We take in the socket that's creating us, the caller's
        // state object, and the buffer on which the I/O will be performed. 
        // We save the socket and state, pin the callers's buffer, and allocate
        // an event for the WaitHandle.
        //
        internal OverlappedAsyncResult(Socket socket, Object asyncState, AsyncCallback asyncCallback) : 
            base(socket, asyncState, asyncCallback)
        { } 
 
        //
        internal IntPtr GetSocketAddressPtr() 
        {
            return Marshal.UnsafeAddrOfPinnedArrayElement(m_SocketAddress.m_Buffer, 0);
        }
        // 
        internal IntPtr GetSocketAddressSizePtr()
        { 
            return Marshal.UnsafeAddrOfPinnedArrayElement(m_SocketAddress.m_Buffer, m_SocketAddress.GetAddressSizeOffset()); 
        }
        // 
        internal SocketAddress SocketAddress {
            get {
                return m_SocketAddress;
            } 
        }
        // 
        internal SocketAddress SocketAddressOriginal { 
            get {
                return m_SocketAddressOriginal; 
            }
            set {
                m_SocketAddressOriginal = value;
            } 
        }
 
        // 
        // SetUnmanagedStructures -
        // Fills in Overlapped Structures used in an Async Overlapped Winsock call 
        //   these calls are outside the runtime and are unmanaged code, so we need
        //   to prepare specific structures and ints that lie in unmanaged memory
        //   since the Overlapped calls can be Async
        // 

        internal void SetUnmanagedStructures(byte[] buffer, int offset, int size, SocketAddress socketAddress, bool pinSocketAddress) 
        { 
            //
            // Fill in Buffer Array structure that will be used for our send/recv Buffer 
            //
            m_SocketAddress = socketAddress;
            if (pinSocketAddress && m_SocketAddress != null)
            { 
                object[]  objectsToPin = null;
                objectsToPin = new object[2]; 
                objectsToPin[0] = buffer; 

                m_SocketAddress.CopyAddressSizeIntoBuffer(); 
                objectsToPin[1] = m_SocketAddress.m_Buffer;

                base.SetUnmanagedStructures(objectsToPin);
            } else { 
                base.SetUnmanagedStructures(buffer);
            } 
 
            m_SingleBuffer.Length = size;
            m_SingleBuffer.Pointer = Marshal.UnsafeAddrOfPinnedArrayElement(buffer, offset); 
        }

        internal void SetUnmanagedStructures(byte[] buffer, int offset, int size, SocketAddress socketAddress, bool pinSocketAddress, ref OverlappedCache overlappedCache)
        { 
            SetupCache(ref overlappedCache);
            SetUnmanagedStructures(buffer, offset, size, socketAddress, pinSocketAddress); 
        } 

        internal void SetUnmanagedStructures(BufferOffsetSize[] buffers) 
        {

            //
            // Fill in Buffer Array structure that will be used for our send/recv Buffer 
            //
            m_WSABuffers = new WSABuffer[buffers.Length]; 
 
            object[] objectsToPin = new object[buffers.Length];
            for (int i = 0; i < buffers.Length; i++) 
                objectsToPin[i] = buffers[i].Buffer;

            // has to be called now to pin memory
            base.SetUnmanagedStructures(objectsToPin); 

            for (int i = 0; i < buffers.Length; i++) 
            { 
                m_WSABuffers[i].Length = buffers[i].Size;
                m_WSABuffers[i].Pointer = Marshal.UnsafeAddrOfPinnedArrayElement(buffers[i].Buffer, buffers[i].Offset); 
            }
        }

        internal void SetUnmanagedStructures(BufferOffsetSize[] buffers, ref OverlappedCache overlappedCache) 
        {
            SetupCache(ref overlappedCache); 
            SetUnmanagedStructures(buffers); 
        }
 
        internal void SetUnmanagedStructures(IList> buffers)
        {

            // Fill in Buffer Array structure that will be used for our send/recv Buffer 
            //
 
            //make sure we don't let the app mess up the buffer array enough to cause 
            //corruption.
            int count = buffers.Count; 
            ArraySegment[] buffersCopy = new ArraySegment[count];

            for (int i=0;i> buffers, ref OverlappedCache overlappedCache) 
        {
            SetupCache(ref overlappedCache); 
            SetUnmanagedStructures(buffers); 
        }
 
        //
        // This method is called after an asynchronous call is made for the user,
        // it checks and acts accordingly if the IO:
        // 1) completed synchronously. 
        // 2) was pended.
        // 3) failed. 
        // 
        internal override object PostCompletion(int numBytes)
        { 
            if (ErrorCode == 0) {
                if(Logging.On)LogBuffer(numBytes);
            }
            return (int)numBytes; 
        }
 
        void LogBuffer(int size) { 
            GlobalLog.Assert(Logging.On, "OverlappedAsyncResult#{0}::LogBuffer()|Logging is off!", ValidationHelper.HashString(this));
            if (size > -1) { 
                if (m_WSABuffers != null) {
                    foreach (WSABuffer wsaBuffer in m_WSABuffers) {
                        Logging.Dump(Logging.Sockets, AsyncObject, "PostCompletion", wsaBuffer.Pointer, Math.Min(wsaBuffer.Length, size));
                        if ((size -= wsaBuffer.Length) <=0) 
                            break;
                    } 
                } 
                else {
                    Logging.Dump(Logging.Sockets, AsyncObject, "PostCompletion", m_SingleBuffer.Pointer, Math.Min(m_SingleBuffer.Length, size)); 
               }
            }
        }
 
    }; // class OverlappedAsyncResult
 
 

 
} // namespace System.Net.Sockets

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