/// <summary>
/// The Execute method is the entrypoint for the system
/// thread pool to execute tasks on the task queue.
/// </summary>
/// <param name="ignored">
/// The ignored parameter is provided in order for the
/// method to match the WaitCallback signature which is
/// required by the .NET QueueUserWorkItem method.
/// </param>
private void Execute(object ignored)
{
while (true)
{
SequencedTask task = null;
lock (_taskQueue)
{
if (_taskQueue.Count == 0)
{
_pending = false;
break;
}
task = _taskQueue.Dequeue();
}
try
{
task.Execute();
}
catch (System.Exception)
{
ThreadPool.UnsafeQueueUserWorkItem(Execute, null);
throw;
}
}
}
/// <summary>
/// The Enqueue method is invoked to add a callback action
/// to the sequencer's queue of operations.
/// </summary>
/// <param name="callback">
/// The callback that is to be invoked.
/// </param>
/// <param name="state">
/// The state information to be passed to the callback
/// method when it is executed.
/// </param>
public void Enqueue(ContextCallback callback, object state)
{
SequencedTask task = new SequencedTask(callback, state, ExecutionContext.Capture());
lock (_taskQueue)
{
_taskQueue.Enqueue(task);
if (_pending == false)
{
_pending = true;
ThreadPool.UnsafeQueueUserWorkItem(Execute, null);
}
}
}
/// <summary>
/// The Enqueue method is invoked to add a callback action
/// to the sequencer's queue of operations.
/// </summary>
/// <param name="callback">
/// The callback that is to be invoked.
/// </param>
/// <param name="state">
/// The state information to be passed to the callback
/// method when it is executed.
/// </param>
public void Enqueue(ContextCallback callback, object state)
{
SequencedTask task = new SequencedTask(callback, state, ExecutionContext.Capture());
lock (_taskQueue)
{
_taskQueue.Enqueue(task);
if (_pending == false)
{
_pending = true;
ThreadPool.UnsafeQueueUserWorkItem(Execute, null);
}
}
}