/// <summary>
/// 开始接收
/// </summary>
/// <param name="stream">Socket网络流</param>
/// <param name="callback">回调函数</param>
/// <param name="state">自定义状态</param>
/// <returns>异步结果</returns>
public IAsyncResult BeginReceive(Stream stream, AsyncCallback callback, object state)
{
//stream不能为null
if (stream == null)
{
throw new ArgumentNullException(nameof(stream));
}
//回调函数不能为null
if (callback == null)
{
throw new ArgumentNullException(nameof(callback));
}
//stream异常
if (!stream.CanRead)
{
throw new ArgumentException("stream不支持读取。");
}
SocketAsyncResult result = new SocketAsyncResult(state);
//初始化SocketHandlerState
SocketHandlerState shs = new SocketHandlerState
{
Data = new byte[2],
AsyncResult = result,
Stream = stream,
AsyncCallBack = callback,
Completed = true
};
//开始异步接收长度为2的头信息
//该头信息包含要接收的主要数据长度
stream.BeginRead(shs.Data, 0, 2, EndRead, shs);
return(result);
}
//stream异步结束写入
private void EndWrite(IAsyncResult ar)
{
SocketHandlerState state = (SocketHandlerState)ar.AsyncState;
//锁定StateSet
lock (StateSet)
StateSet.Add(state.AsyncResult, state);
try
{
state.Stream.EndWrite(ar);
}
catch
{
//出现Socket异常，发送失败
state.Completed = false;
//允许等待线程继续
((AutoResetEvent)state.AsyncResult.AsyncWaitHandle).Set();
//执行异步回调函数
state.AsyncCallBack(state.AsyncResult);
return;
}
//发送成功
state.Completed = true;
//允许等待线程继续
((AutoResetEvent)state.AsyncResult.AsyncWaitHandle).Set();
//执行异步回调函数
state.AsyncCallBack(state.AsyncResult);
//锁定SendQueue
lock (SendQueue)
{
SocketHandlerState Prepare = null;
//移除当前发送完成的数据
SendQueue.Remove(state);
//如果SendQueue还有数据存在，则继续发送
if (SendQueue.Count > 0)
{
Prepare = SendQueue[0];
}
if (Prepare != null)
{
//获取数据长度
//ushort的最大值为65535
//转换为byte[]长度为2
var dataLength = BitConverter.GetBytes((ushort)Prepare.Data.Length);
//向对方发送长度为2的头信息，表示接下来要发送的数据长度
Prepare.Stream.Write(dataLength, 0, dataLength.Length);
//开始异步发送数据
Prepare.Stream.BeginWrite(Prepare.Data, 0, Prepare.Data.Length, EndWrite, Prepare).AsyncWaitHandle.WaitOne();
}
}
}
/// <summary>
/// 结束发送
/// </summary>
/// <param name="asyncResult">异步结果</param>
/// <returns>发送是否成功</returns>
public bool EndSend(IAsyncResult asyncResult)
{
//判断异步操作状态是否属于当前处理程序
if (!StateSet.ContainsKey(asyncResult))
{
throw new ArgumentException("无法识别的asyncResult。");
}
SocketHandlerState state = StateSet[asyncResult];
lock (StateSet)
StateSet.Remove(asyncResult);
return(state.Completed);
}
/// <summary>
/// 结束接收
/// </summary>
/// <param name="asyncResult">异步结果</param>
/// <returns>接收到的数据</returns>
public byte[] EndReceive(IAsyncResult asyncResult)
{
//判断异步操作状态是否属于当前处理程序
if (!StateSet.ContainsKey(asyncResult))
{
throw new ArgumentException("无法识别的asyncResult。");
}
SocketHandlerState state = StateSet[asyncResult];
lock (StateSet)
StateSet.Remove(asyncResult);
return(state.Data);
}
//stream异步结束读取
private void EndRead(IAsyncResult ar)
{
SocketHandlerState state = (SocketHandlerState)ar.AsyncState;
int dataLength;
try
{
dataLength = state.Stream.EndRead(ar);
}
catch
{
dataLength = 0;
}
//dataLength为0则表示Socket断开连接
if (dataLength == 0)
{
lock (StateSet)
StateSet.Add(state.AsyncResult, state);
//设定接收到的数据位空byte数组
state.Data = new byte[0];
//允许等待线程继续
((AutoResetEvent)state.AsyncResult.AsyncWaitHandle).Set();
//执行异步回调函数
state.AsyncCallBack(state.AsyncResult);
return;
}
//如果是已完成状态，则表示state.Data的数据是头信息
if (state.Completed)
{
//设定状态为未完成
state.Completed = false;
//已接收得数据长度为0
state.DataLength = 0;
//获取主要数据长度
var length = BitConverter.ToUInt16(state.Data, 0);
//初始化数据的byte数组
state.Data = new byte[length];
try
{
//开始异步接收主要数据
state.Stream.BeginRead(state.Data, 0, length, EndRead, state);
}
catch
{
//出现Socket异常
lock (StateSet)
StateSet.Add(state.AsyncResult, state);
state.Data = new byte[0];
((AutoResetEvent)state.AsyncResult.AsyncWaitHandle).Set();
state.AsyncCallBack(state.AsyncResult);
}
return;
}
//接收到主要数据
else
{
//判断是否接收了完整的数据
if (dataLength + state.DataLength != state.Data.Length)
{
//增加已接收数据长度
state.DataLength += dataLength;
try
{
//继续接收数据
state.Stream.BeginRead(state.Data, state.DataLength, state.Data.Length - state.DataLength, EndRead, state);
}
catch
{
//出现Socket异常
lock (StateSet)
StateSet.Add(state.AsyncResult, state);
state.Data = new byte[0];
((AutoResetEvent)state.AsyncResult.AsyncWaitHandle).Set();
state.AsyncCallBack(state.AsyncResult);
return;
}
return;
}
//接收完成
state.Completed = true;
lock (StateSet)
StateSet.Add(state.AsyncResult, state);
((AutoResetEvent)state.AsyncResult.AsyncWaitHandle).Set();
state.AsyncCallBack(state.AsyncResult);
}
}
/// <summary>
/// 开始发送
/// </summary>
/// <param name="data">要发送的数据</param>
/// <param name="offset">数据偏移</param>
/// <param name="count">发送长度</param>
/// <param name="stream">Socket网络流</param>
/// <param name="callback">回调函数</param>
/// <param name="state">自定义状态</param>
/// <returns>异步结果</returns>
public IAsyncResult BeginSend(byte[] data, int offset, int count, Stream stream, AsyncCallback callback, object state)
{
//data不能为null
if (data == null)
{
throw new ArgumentNullException(nameof(data));
}
//offset不能小于0和超过data长度
if (offset > data.Length || offset < 0)
{
throw new ArgumentOutOfRangeException(nameof(offset));
}
//count不能大于65535
if (count <= 0 || count > data.Length - offset || count > ushort.MaxValue)
{
throw new ArgumentOutOfRangeException(nameof(count));
}
//stream不能为null
if (stream == null)
{
throw new ArgumentNullException(nameof(stream));
}
//回调函数不能为null
if (callback == null)
{
throw new ArgumentNullException(nameof(callback));
}
//stream异常
if (!stream.CanWrite)
{
throw new ArgumentException("stream不支持写入。");
}
SocketAsyncResult result = new SocketAsyncResult(state);
//初始化SocketHandlerState
SocketHandlerState shs = new SocketHandlerState
{
Data = data,
AsyncResult = result,
Stream = stream,
AsyncCallBack = callback,
DataLength = 0
};
//锁定SendQueue
//避免多线程同时发送数据
lock (SendQueue)
{
//添加状态
SendQueue.Add(shs);
//如果SendQueue数量大于1，则表示有数据尚未发送完成
if (SendQueue.Count > 1)
{
return(result);
}
}
//获取数据长度
//ushort的最大值为65535
//转换为byte[]长度为2
var dataLength = BitConverter.GetBytes((ushort)data.Length);
//向对方发送长度为2的头信息，表示接下来要发送的数据长度
stream.Write(dataLength, 0, dataLength.Length);
//开始异步发送数据
stream.BeginWrite(shs.Data, 0, shs.Data.Length, EndWrite, shs).AsyncWaitHandle.WaitOne();
return(result);
}