我使用的SocketAsyncEventArgs看着一個服務器的源代碼,我試圖找出如何這會不會導致堆棧溢出:這不會導致堆棧溢出?
所以這段代碼被稱爲允許插座接受傳入連接(向下滾動至底部,明白我的意思):
/// <summary>
/// Begins an operation to accept a connection request from the client.
/// </summary>
/// <param name="acceptEventArg">The context object to use when issuing
/// the accept operation on the server's listening socket.</param>
private void StartAccept(SocketAsyncEventArgs acceptEventArg)
{
if (acceptEventArg == null)
{
acceptEventArg = new SocketAsyncEventArgs();
acceptEventArg.Completed += new EventHandler<SocketAsyncEventArgs>(OnAcceptCompleted);
}
else
{
// Socket must be cleared since the context object is being reused.
acceptEventArg.AcceptSocket = null;
}
this.semaphoreAcceptedClients.WaitOne();
Boolean willRaiseEvent = this.listenSocket.AcceptAsync(acceptEventArg);
if (!willRaiseEvent)
{
this.ProcessAccept(acceptEventArg);
}
}
然後這個代碼被調用一次的連接實際上是接受(見最後一行):
/// <summary>
/// Process the accept for the socket listener.
/// </summary>
/// <param name="e">SocketAsyncEventArg associated with the completed accept operation.</param>
private void ProcessAccept(SocketAsyncEventArgs e)
{
if (e.BytesTransferred > 0)
{
Interlocked.Increment(ref this.numConnectedSockets);
Console.WriteLine("Client connection accepted. There are {0} clients connected to the server",
this.numConnectedSockets);
}
// Get the socket for the accepted client connection and put it into the
// ReadEventArg object user token.
SocketAsyncEventArgs readEventArgs = this.readWritePool.Pop();
readEventArgs.UserToken = e.AcceptSocket;
// As soon as the client is connected, post a receive to the connection.
Boolean willRaiseEvent = e.AcceptSocket.ReceiveAsync(readEventArgs);
if (!willRaiseEvent)
{
this.ProcessReceive(readEventArgs);
}
// Accept the next connection request.
this.StartAccept(e); // <==== tail end recursive?
}
看看最後一個線。它再次調用頂層函數。這是如何通過在這兩個函數之間來回跳動來溢出堆棧的?這似乎是尾端遞歸,但這不是Haskell,所以我不明白這是如何工作的。
這是我的理解,這些不是在線程中被解僱,而是由cpu一次執行一個。