/// <summary>
/// Waits for any of the work items in the specified array to complete, cancel, or timeout
/// </summary>
/// <param name="waitableResults">Array of work item result objects</param>
/// <param name="millisecondsTimeout">The number of milliseconds to wait, or Timeout.Infinite (-1) to wait indefinitely.</param>
/// <param name="exitContext">
/// true to exit the synchronization domain for the context before the wait (if in a synchronized context), and reacquire it; otherwise, false.
/// </param>
/// <param name="cancelWaitHandle">A cancel wait handle to interrupt the wait if needed</param>
/// <returns>
/// The array index of the work item result that satisfied the wait, or WaitTimeout if no work item result satisfied the wait and a time interval equivalent to millisecondsTimeout has passed or the work item has been canceled.
/// </returns>
internal static int WaitAny(
IWaitableResult[] waitableResults,
int millisecondsTimeout,
bool exitContext,
WaitHandle cancelWaitHandle)
{
WaitHandle[] waitHandles;
if (null != cancelWaitHandle)
{
waitHandles = new WaitHandle[waitableResults.Length + 1];
GetWaitHandles(waitableResults, waitHandles);
waitHandles[waitableResults.Length] = cancelWaitHandle;
}
else
{
waitHandles = new WaitHandle[waitableResults.Length];
GetWaitHandles(waitableResults, waitHandles);
}
int result = STPEventWaitHandle.WaitAny(waitHandles, millisecondsTimeout, exitContext);
// Treat cancel as timeout
if (null != cancelWaitHandle)
{
if (result == waitableResults.Length)
{
result = STPEventWaitHandle.WaitTimeout;
}
}
ReleaseWaitHandles(waitableResults);
return(result);
}
/// <summary>
/// Get the result of the work item.
/// If the work item didn't run yet then the caller waits for the result, timeout, or cancel.
/// In case of error the e argument is filled with the exception
/// </summary>
/// <returns>The result of the work item</returns>
private object GetResult(
int millisecondsTimeout,
bool exitContext,
WaitHandle cancelWaitHandle,
out Exception e)
{
e = null;
// Check for cancel
if (WorkItemState.Canceled == GetWorkItemState())
{
throw new WorkItemCancelException("Work item canceled");
}
// Check for completion
if (IsCompleted)
{
e = _exception;
return(_result);
}
// If no cancelWaitHandle is provided
if (null == cancelWaitHandle)
{
WaitHandle wh = GetWaitHandle();
bool timeout = !STPEventWaitHandle.WaitOne(wh, millisecondsTimeout, exitContext);
ReleaseWaitHandle();
if (timeout)
{
throw new WorkItemTimeoutException("Work item timeout");
}
}
else
{
WaitHandle wh = GetWaitHandle();
int result = STPEventWaitHandle.WaitAny(new WaitHandle[] { wh, cancelWaitHandle });
ReleaseWaitHandle();
switch (result)
{
case 0:
// The work item signaled
// Note that the signal could be also as a result of canceling the
// work item (not the get result)
break;
case 1:
case STPEventWaitHandle.WaitTimeout:
throw new WorkItemTimeoutException("Work item timeout");
default:
Debug.Assert(false);
break;
}
}
// Check for cancel
if (WorkItemState.Canceled == GetWorkItemState())
{
throw new WorkItemCancelException("Work item canceled");
}
Debug.Assert(IsCompleted);
e = _exception;
// Return the result
return(_result);
}
/// <summary>
/// Wait for all work items to complete
/// </summary>
/// <param name="waitableResults">Array of work item result objects</param>
/// <param name="millisecondsTimeout">The number of milliseconds to wait, or Timeout.Infinite (-1) to wait indefinitely.</param>
/// <param name="exitContext">
/// true to exit the synchronization domain for the context before the wait (if in a synchronized context), and reacquire it; otherwise, false.
/// </param>
/// <param name="cancelWaitHandle">A cancel wait handle to interrupt the wait if needed</param>
/// <returns>
/// true when every work item in waitableResults has completed; otherwise false.
/// </returns>
internal static bool WaitAll(
IWaitableResult[] waitableResults,
int millisecondsTimeout,
bool exitContext,
WaitHandle cancelWaitHandle)
{
if (0 == waitableResults.Length)
{
return(true);
}
bool success;
WaitHandle[] waitHandles = new WaitHandle[waitableResults.Length];
GetWaitHandles(waitableResults, waitHandles);
if ((null == cancelWaitHandle) && (waitHandles.Length <= 64))
{
success = STPEventWaitHandle.WaitAll(waitHandles, millisecondsTimeout, exitContext);
}
else
{
success = true;
int millisecondsLeft = millisecondsTimeout;
Stopwatch stopwatch = Stopwatch.StartNew();
WaitHandle[] whs;
if (null != cancelWaitHandle)
{
whs = new WaitHandle[] { null, cancelWaitHandle };
}
else
{
whs = new WaitHandle[] { null };
}
bool waitInfinitely = (Timeout.Infinite == millisecondsTimeout);
// Iterate over the wait handles and wait for each one to complete.
// We cannot use WaitHandle.WaitAll directly, because the cancelWaitHandle
// won't affect it.
// Each iteration we update the time left for the timeout.
for (int i = 0; i < waitableResults.Length; ++i)
{
// WaitAny don't work with negative numbers
if (!waitInfinitely && (millisecondsLeft < 0))
{
success = false;
break;
}
whs[0] = waitHandles[i];
int result = STPEventWaitHandle.WaitAny(whs, millisecondsLeft, exitContext);
if ((result > 0) || (STPEventWaitHandle.WaitTimeout == result))
{
success = false;
break;
}
if (!waitInfinitely)
{
// Update the time left to wait
millisecondsLeft = millisecondsTimeout - (int)stopwatch.ElapsedMilliseconds;
}
}
}
// Release the wait handles
ReleaseWaitHandles(waitableResults);
return(success);
}