CSocket的accept()函数

CSocket* CSocket::Accept(int &error)
{
    if (m_pSocketThread)
    {
        m_pSocketThread->m_sync.Lock();
	
	//修改本socket结合的thread的等待标记
        m_pSocketThread->m_waiting |= WAIT_ACCEPT;

	//如果thread处于wait中，就激活它，开始工作
        m_pSocketThread->WakeupThread(true);
        m_pSocketThread->m_sync.Unlock();
    }

    //接受一个连接的socket
    int fd = accept(m_fd, 0, 0);
    if (fd == -1)
    {
#ifdef __WXMSW__
        error = ConvertMSWErrorCode(WSAGetLastError());
#else
        error = errno;
#endif
        return 0;
    }
    
#if defined(SO_NOSIGPIPE) && !defined(MSG_NOSIGNAL)
    // We do not want SIGPIPE if writing to socket.
    const int value = 1;
    setsockopt(fd, SOL_SOCKET, SO_NOSIGPIPE, &value, sizeof(int));
#endif

    //设置为nonblock
    SetNonblocking(fd);

    //设置接受和发送缓冲大小
    DoSetBufferSizes(fd, m_buffer_sizes[0], m_buffer_sizes[1]);

    //为新建立的socket建立一个我们的CSocket封装，并为其建立一个thread，然后
    //将这个CSocket交给thread, thread的设置为等待读或者写
    CSocket* pSocket = new CSocket(0);
    pSocket->m_state = connected;
    pSocket->m_fd = fd;
    pSocket->m_pSocketThread = new CSocketThread();
    pSocket->m_pSocketThread->SetSocket(pSocket);
    pSocket->m_pSocketThread->m_waiting = WAIT_READ | WAIT_WRITE;
    pSocket->m_pSocketThread->Start();

    return pSocket;
}


int CSocket::SetNonblocking(int fd)
{
    // Set socket to non-blocking.
#ifdef __WXMSW__
    unsigned long nonblock = 1;
    int res = ioctlsocket(fd, FIONBIO, &nonblock);
    if (!res)
        return 0;
    else
        return ConvertMSWErrorCode(WSAGetLastError());
#else

    //通用的方法是首先获得该fd的flags，然后在它的基础上修改，这样比较安全
    int flags = fcntl(fd, F_GETFL);
    if (flags == -1)
        return errno;
    int res = fcntl(fd, F_SETFL, flags | O_NONBLOCK);
    if (res == -1)
        return errno;
    return 0;
#endif
}
int CSocket::DoSetBufferSizes(int fd, int size_read, int size_write)
{
    //分别调用setsockopt来设置socket的接收和发送缓冲的大小
    if (size_read != -1)
    {
        int res = setsockopt(fd, SOL_SOCKET, SO_RCVBUF, (const char*)&size_read, sizeof(size_read));
        if (res != 0)
#ifdef __WXMSW__
            return ConvertMSWErrorCode(WSAGetLastError());
#else
            return errno;
#endif
    }

    if (size_write != -1)
    {
        int res = setsockopt(fd, SOL_SOCKET, SO_SNDBUF, (const char*)&size_write, sizeof(size_write));
        if (res != 0)
#ifdef __WXMSW__
            return ConvertMSWErrorCode(WSAGetLastError());
#else
            return errno;
#endif
    }

    return 0;
}