public override void Schedule(SchedulerContext <TaskInfo> context, TaskInfo task)
{
context.Queue.Enqueue(task);
context.RaiseTaskScheduled(new TaskEventArgs(task));
Next(context);
}
public override void Start(SchedulerContext <TaskInfo> context)
{
if (context.IsStarted)
{
throw new InvalidCastException("Queue has already been started.");
}
context.IsStarted = true;
context.IsStopped = false;
Next(context);
context.RaiseQueueStarted(new QueueEventArgs());
}
public override void Clear(SchedulerContext <TaskInfo> context)
{
if (context.IsBusy)
{
throw new InvalidOperationException();
}
while (context.Queue.Count > 0)
{
var task = context.Queue.Dequeue();
context.RaiseTaskCanceled(new TaskEventArgs(task));
}
}
public override void Stop(SchedulerContext <TaskInfo> context)
{
if (!context.IsStarted)
{
throw new InvalidCastException("Queue has not been started.");
}
context.CancellationTokenSource.Cancel();
context.IsStarted = false;
context.IsStopped = true;
context.IsRunning = false;
context.IsBusy = false;
context.RaiseQueueStopped(new QueueEventArgs());
}
public override void Deschedule(SchedulerContext <TaskInfo> context, TaskInfo task)
{
var item = context.Queue.FirstOrDefault(x => x == task);
if (item == null)
{
throw new InvalidOperationException("Not part of this queue.");
}
var e = new TaskCancelingEventArgs(task, true);
context.RaiseTaskCanceling(e);
if (e.Cancel)
{
context.Remove(item);
var e2 = new TaskEventArgs(task);
context.RaiseTaskCanceled(e2);
}
}
public override async Task Next(SchedulerContext <TaskInfo> context)
{
if (context.CancellationToken.IsCancellationRequested)
{
return;
}
if (!context.IsBusy)
{
// Do not fetch next task if the queue has not been started.
if (!context.IsStarted)
{
return;
}
if (context.Queue.Count > 0)
{
// Optional delay.
if (context.Delay > default(TimeSpan))
{
await Task.Delay(context.Delay);
}
// Peek the current task.
context._current = context.Queue.Peek();
try
{
context.IsRunning = true;
context.IsBusy = true;
// Execute the current task.
context.RaiseTaskExecuting(new TaskEventArgs(context._current));
await context._current.Action(context._current, context.CancellationToken);
}
catch (Exception exc)
{
// Handle any exception thrown inside a task.
// Invoke the Exception event handlers.
var eventArgs = new TaskExceptionEventArgs(context._current, exc, context.CancelOnException);
context.RaiseTaskException(eventArgs);
if (eventArgs.Cancel)
{
// Cancel the queue.
ClearCore(context);
}
}
context.RaiseTaskExecuted(new TaskEventArgs(context._current));
context._current = null;
// Dequeue the currently finished task and request the next.
if (context.Queue.Count > 0)
{
context.Queue.Dequeue();
}
context.IsBusy = false;
await Next(context);
}
else
{
context.RaiseQueueEmpty(new QueueEventArgs());
}
}
else
{
context.IsRunning = false;
}
}
private void ClearCore(SchedulerContext <TaskInfo> context)
{
context.IsBusy = false;
Clear(context);
}
