/// <summary>
/// Attempts to execute the delegate immediately, on the calling thread, without scheduling.
/// </summary>
/// <param name="synchronizationObject">Synchronization object.</param>
/// <param name="action">Action to execute.</param>
/// <param name="startTime">Scheduled start time.</param>
/// <param name="context">The scheduler context on which to execute the action.</param>
/// <returns>Success flag.</returns>
public bool TryExecute(SynchronizationLock synchronizationObject, Action action, DateTime startTime, SchedulerContext context)
{
if (this.forcedShutdownRequested || startTime > context.FinalizeTime)
{
return(true);
}
if (startTime > this.clock.GetCurrentTime() && this.delayFutureWorkitemsUntilDue)
{
return(false);
}
if (!this.isSchedulerThread.Value && !this.allowSchedulingOnExternalThreads)
{
// this thread is not ours, so return
return(false);
}
// try to acquire a lock
// however, if this thread already has the lock, we have to give up to keep the no-reentrancy guarantee
if (!synchronizationObject.TryLock())
{
return(false);
}
// ExecuteAndRelease assumes that the context has already been entered, so we must explicitly
// enter it here. The context will be exited just prior to returning from ExecuteAndRelease.
context.Enter();
this.ExecuteAndRelease(synchronizationObject, action, context);
this.counters?.Increment(SchedulerCounters.ImmediateWorkitemsPerSecond);
return(true);
}
/// <summary>
/// Enqueues a workitem and, if possible, kicks off a worker thread to pick it up.
/// </summary>
/// <param name="synchronizationObject">Synchronization object.</param>
/// <param name="action">Action to execute.</param>
/// <param name="startTime">Scheduled start time.</param>
/// <param name="context">The scheduler context on which to schedule the action.</param>
/// <param name="asContinuation">Flag whether to execute once current operation completes.</param>
/// <param name="allowSchedulingPastFinalization">Allow scheduling past finalization time.</param>
public void Schedule(SynchronizationLock synchronizationObject, Action action, DateTime startTime, SchedulerContext context, bool asContinuation = true, bool allowSchedulingPastFinalization = false)
{
if (synchronizationObject == null || action == null || context == null)
{
throw new ArgumentNullException();
}
// Enter the context to track this new work item. The context will be exited
// only after the work item has been successfully executed (or dropped).
context.Enter();
this.Schedule(new WorkItem() { SyncLock = synchronizationObject, Callback = action, StartTime = startTime, SchedulerContext = context });
}
/// <summary>
/// Attempts to execute the delegate immediately, on the calling thread, without scheduling.
/// </summary>
/// <typeparam name="T">Action argument type.</typeparam>
/// <param name="synchronizationObject">Synchronization object.</param>
/// <param name="action">Action to execute.</param>
/// <param name="argument">Action argument.</param>
/// <param name="startTime">Scheduled start time.</param>
/// <param name="context">The scheduler context on which to execute the action.</param>
/// <returns>Success flag.</returns>
public bool TryExecute <T>(SynchronizationLock synchronizationObject, Action <T> action, T argument, DateTime startTime, SchedulerContext context)
{
if (this.forcedShutdownRequested || startTime > context.FinalizeTime)
{
return(true);
}
if (startTime > this.clock.GetCurrentTime() && this.delayFutureWorkitemsUntilDue)
{
return(false);
}
if (!this.isSchedulerThread.Value && !this.allowSchedulingOnExternalThreads)
{
// this thread is not ours, so return
return(false);
}
// try to acquire a lock on the sync context
// however, if this thread already has the lock, we have to give up to keep the no-reentrancy guarantee
if (!synchronizationObject.TryLock())
{
return(false);
}
try
{
// Unlike ExecuteAndRelease, which assumes that the context has already been entered (e.g.
// when the work item was first created), we need to explicitly enter the context prior to
// running the action. The context will be exited in the finally clause.
context.Enter();
action(argument);
this.counters?.Increment(SchedulerCounters.WorkitemsPerSecond);
this.counters?.Increment(SchedulerCounters.ImmediateWorkitemsPerSecond);
}
catch (Exception e) when(this.errorHandler(e))
{
}
finally
{
synchronizationObject.Release();
context.Exit();
}
return(true);
}
