//---------------------------------------------------------------------
// APM
//--
public IAsyncResult BeginWaitEx(int timeout, CancellationToken ctk,
AsyncCallback ucb, object ustate)
{
bool result = true;
lock (_lock)
{
if (currentPermits > 0)
{
currentPermits -= 1;
}
else if (timeout == 0 || ctk.IsCancellationRequested)
{
result = false;
}
else
{
var waiter = new ApmWaiter <Data>(new Data(), ucb, ustate, ctk, timeout, AsyncUnlink);
DListNode.AddLast(waiters, waiter);
waiter.Enable();
return(waiter.AsyncResult);
}
}
// FromResult will invoke the async callbacks, so do it outside of the lock
if (result)
{
return(GenericAsyncResult <bool> .FromResult(ucb, ustate, true, null, true));
}
// synchronous completion due to timeout or cancellation
return(ctk.IsCancellationRequested ?
GenericAsyncResult <bool> .FromResult(ucb, ustate, false, new OperationCanceledException(ctk), true) :
GenericAsyncResult <bool> .FromResult(ucb, ustate, false, null, true));
}
//
// File copy using synchronous read and write operations.
//
public static IAsyncResult BeginCopySync(Stream src, Stream dst,
AsyncCallback cb, object state)
{
byte[] buffer = new byte[BUFFER_SIZE];
long fileSize = 0;
try {
int bytesRead;
while ((bytesRead = src.Read(buffer, 0, buffer.Length)) != 0)
{
dst.Write(buffer, 0, bytesRead);
fileSize += bytesRead;
}
} finally {
src.Close();
dst.Close();
}
return(GenericAsyncResult <long> .FromResult(cb, state, fileSize, null, true));
}
