/// <summary>
/// queues the given ui update action to be done in order of time stamp
/// </summary>
/// <param name="timeStamp">frame time stamp</param>
/// <param name="context">the synchronization context to perform the UI update action</param>
/// <param name="uiUpdateAction">the task which, upon completion, will produce the UI update action</param>
public void QueueAction(UInt64 timeStamp,
SynchronizationContext context, Task <Action> uiUpdateAction)
{
lock (syncObject)
{
// find or create the update batch to be used
FrameUpdateBatch batch =
FrameUpdateBatch.GetOrCreateBatch(timeStamp, context,
ref _queuedBatches);
// and add to the queue
batch.UiUpdateActions.Enqueue(uiUpdateAction);
}
}
/// <summary>
/// either retrieves or creates a FrameUpdateBatch for the given time stamp
/// </summary>
/// <param name="timeStamp">the frame time stamp</param>
/// <param name="context">the synchronization context for the frame</param>
/// <param name="queue">the queue to add the batch to, or to find the batch on</param>
/// <returns>the FrameUpdateBatch</returns>
public static FrameUpdateBatch GetOrCreateBatch(UInt64 timeStamp,
SynchronizationContext context,
ref ConcurrentQueue <FrameUpdateBatch> queue)
{
FrameUpdateBatch batch =
queue.FirstOrDefault(b =>
b.TimeStamp == timeStamp &&
b.Context == context);
if (batch == null)
{
batch = new FrameUpdateBatch();
batch.TimeStamp = timeStamp;
batch.Context = context;
batch.UiUpdateActions = new ConcurrentQueue <Task <Action> >();
queue.Enqueue(batch);
}
return(batch);
}
/// <summary>
/// called to attempt processing of frame batches in the queue
/// </summary>
public void ProcessQueue()
{
FrameUpdateBatch nextBatch = null;
lock (syncObject)
{
if (_queuedBatches.TryPeek(out nextBatch))
{
var nextBatchList = nextBatch.UiUpdateActions.ToList();
if (nextBatchList.TrueForAll(t => t.IsCompleted))
{
// now perform the UI update response actions
UiUpdatePerformance.StartEvent();
Task <Action> uiUpdateAction;
while (nextBatch.UiUpdateActions.TryDequeue(out uiUpdateAction))
{
var action = uiUpdateAction.Result;
action.Invoke();
}
UiUpdatePerformance.EndEvent();
// now remove from the queue, if possible
FrameUpdateBatch dummy;
_queuedBatches.TryDequeue(out dummy);
System.Diagnostics.Trace.Assert(dummy.UiUpdateActions.IsEmpty);
FrameUpdateBatch next;
if (_queuedBatches.TryPeek(out next))
{
System.Diagnostics.Trace.Assert(next.TimeStamp > dummy.TimeStamp);
}
}
}
}
}
