private TaskCommon TaskListRemoveFirst()
{
if (_taskCommonListHead == null)
{
return(null);
}
if (object.ReferenceEquals(_taskCommonListHead._next, _taskCommonListHead))
{
TaskCommon taskCommonListHead = _taskCommonListHead;
_taskCommonListHead = null;
_taskCommonCount--;
taskCommonListHead._next = null;
taskCommonListHead._previous = null;
return(taskCommonListHead);
}
TaskCommon taskCommonListHead2 = _taskCommonListHead;
_taskCommonListHead = _taskCommonListHead._next;
_taskCommonListHead._previous = taskCommonListHead2._previous;
_taskCommonListHead._previous._next = _taskCommonListHead;
_taskCommonCount--;
taskCommonListHead2._next = null;
taskCommonListHead2._previous = null;
return(taskCommonListHead2);
}
private void TaskListAddLast(TaskCommon Item)
{
if (_taskCommonListHead == null)
{
_taskCommonListHead = Item;
Item._next = Item;
Item._previous = Item;
}
else
{
_taskCommonListHead._previous._next = Item;
Item._previous = _taskCommonListHead._previous;
Item._next = _taskCommonListHead;
_taskCommonListHead._previous = Item;
}
_taskCommonCount++;
}
public virtual bool Enqueue(ITask task)
{
ITask task2 = null;
bool flag = false;
if (task == null)
{
throw new ArgumentNullException("task");
}
task.TaskQueue = this;
if (_dispatcher == null)
{
_scheduledTaskCount += 1L;
ThreadPool.QueueUserWorkItem(new WaitCallback(TaskExecutionWorker.ExecuteInCurrentThreadContext), task);
return(task2 == null);
}
lock (_taskQueue)
{
if (_isDisposed)
{
if ((_dispatcher.Options & DispatcherOptions.SuppressDisposeExceptions) == DispatcherOptions.None)
{
throw new ObjectDisposedException(typeof(DispatcherQueue).Name + ":" + Name);
}
return(false);
}
else
{
switch (_policy)
{
case TaskExecutionPolicy.Unconstrained:
{
TaskCommon taskCommon = task as TaskCommon;
if (taskCommon != null)
{
TaskListAddLast(taskCommon);
}
else
{
_taskQueue.Enqueue(task);
}
break;
}
case TaskExecutionPolicy.ConstrainQueueDepthDiscardTasks:
RecalculateSchedulingRate();
if (_taskQueue.Count >= _maximumQueueDepth)
{
Dispatcher.LogInfo("DispatcherQueue.Enqueue: Discarding oldest task because queue depth limit reached");
ITask task3;
TryDequeue(out task3);
task2 = task3;
}
_taskQueue.Enqueue(task);
break;
case TaskExecutionPolicy.ConstrainQueueDepthThrottleExecution:
RecalculateSchedulingRate();
if (_taskQueue.Count >= _maximumQueueDepth)
{
Dispatcher.LogInfo("DispatcherQueue.Enqueue: Forcing thread sleep because queue depth limit reached");
while (_taskQueue.Count >= _maximumQueueDepth)
{
Sleep();
}
flag = true;
}
_taskQueue.Enqueue(task);
break;
case TaskExecutionPolicy.ConstrainSchedulingRateDiscardTasks:
RecalculateSchedulingRate();
if (_currentSchedulingRate >= _maximumSchedulingRate)
{
Dispatcher.LogInfo("DispatcherQueue.Enqueue: Discarding task because task scheduling rate exceeded");
ITask task4;
TryDequeue(out task4);
task2 = task4;
}
_scheduledItems += 1.0;
_taskQueue.Enqueue(task);
break;
case TaskExecutionPolicy.ConstrainSchedulingRateThrottleExecution:
RecalculateSchedulingRate();
if (_currentSchedulingRate >= _maximumSchedulingRate)
{
Dispatcher.LogInfo("DispatcherQueue.Enqueue: Forcing thread sleep because task scheduling rate exceeded");
while (_currentSchedulingRate > _maximumSchedulingRate)
{
Sleep();
RecalculateSchedulingRate();
}
flag = true;
}
_scheduledItems += 1.0;
_taskQueue.Enqueue(task);
break;
}
_scheduledTaskCount += 1L;
SignalDispatcher();
}
}
if (task2 != null || flag)
{
TaskExecutionPolicyEngaged(task2, flag);
}
return(task2 == null);
}
