private void AddTask(Task awaitedTask)
{
Contract.Requires(Thread.VolatileRead(ref _ready) == 0);
if (awaitedTask.Status != TaskStatus.RanToCompletion)
{
Interlocked.Increment(ref _count);
if (awaitedTask.AddTaskContinuation(this, /*addBeforeOthers:*/ true))
{
var tasks = Interlocked.CompareExchange(ref _tasks, null, null);
if (tasks == null)
{
return;
}
var index = Array.IndexOf(tasks, null);
while (Interlocked.CompareExchange(ref tasks[index], awaitedTask, null) != null)
{
index = (index + 1) % tasks.Length;
}
}
else
{
Interlocked.Decrement(ref _count);
}
}
}
private void AddTask(Task awaitedTask)
{
Contract.Requires(Thread.VolatileRead(ref _ready) == 0);
Interlocked.Increment(ref _count);
if (!awaitedTask.AddTaskContinuation(this, /*addBeforeOthers:*/ true))
{
Interlocked.Decrement(ref _count);
}
}
private void AddTask(Task awaitedTask)
{
Contract.Requires(Thread.VolatileRead(ref _ready) == 0);
// Get the tasks
var tasks = Interlocked.CompareExchange(ref _tasks, null, null);
// If there are no tasks (Disposed) there is nothing to do
if (tasks == null)
{
return;
}
// Only add tasks taht has not completed
if (awaitedTask.Status == TaskStatus.RanToCompletion)
{
return;
}
// Preemptively increment _count
// So that is has already been incremented when the continuation runs
Interlocked.Increment(ref _count);
// Add the continuation
if (awaitedTask.AddTaskContinuation(this, /*addBeforeOthers:*/ true))
{
// Find a spot in the tasks
var index = Array.IndexOf(tasks, null);
// Try to add the task
while (Interlocked.CompareExchange(ref tasks[index], awaitedTask, null) != null)
{
index = (index + 1) % tasks.Length;
}
// Check again if the task has completed, it may have completed while we were adding it
if (awaitedTask.Status == TaskStatus.RanToCompletion)
{
// Perhaps it did complete:
// - Before adding the continuation -> nothing to do
// - After adding the continuation before adding the task -> We have an orphan task to remove
// - After adding the continuation and the task -> nothing to do
// Remove the orphan task if it is there
Interlocked.CompareExchange(ref tasks[index], null, awaitedTask);
// Note: we let the continuation decrement _count
}
}
else
{
// We failed to add the continuation
// Decrement the _count
Interlocked.Decrement(ref _count);
CheckCount();
}
}
