public ReadWriteLock()
{
mWritingThread = null;
mWriteRequests = new Queue <Thread>();
mReaderDict = new Dictionary <Thread, int>();
mLock = new object();
}
public void lockWrite()
{
Monitor.Enter(mLock);
try {
Thread thisThread = Thread.CurrentThread;
/*如果没有写线程 或者 请求写的线程不是当前正在写的线程（不是写重入）， 就加入写队列*/
if (mWritingThread == null || thisThread != mWritingThread.WritingThread)
{
mWriteRequests.Enqueue(thisThread);
}
while (!canWrite(thisThread)) //如果当前线程无法写，等待
{
Monitor.Wait(mLock);
}
if (null == mWritingThread) //不是写重入
{
mWritingThread = new CurrentWritingThread(thisThread);
mWriteRequests.Dequeue();//从写请求队列中删除
}
else //写重入
{
mWritingThread.writeCount++;
}
}
catch (ThreadInterruptedException e) {
throw e;
}
finally {
Monitor.Exit(mLock);
}
}
public void unlockWrite()
{
Monitor.Enter(mLock);
try {
Thread thisThread = Thread.CurrentThread;
if (1 == mWritingThread.writeCount) // 如果不是重入的写锁
{
mWritingThread = null; //把当前正在写的线程记为null
}
else
{
mWritingThread.writeCount--; // 重入计数减一
}
Monitor.PulseAll(mLock); //唤醒所有线程
}
catch (ThreadInterruptedException e) {
throw e;
}
finally {
Monitor.Exit(mLock);
}
}
