/// <summary>
/// If a task uses no shared resources, deadlock will be avoided. Otherwise,
/// call is delegated to a manager that uses Banker's algorithm and decides whether deadlock can be avoided <see cref="IBankerAlgorithm"/>.
/// </summary>
private bool CanAvoidDeadlock(PrioritizedLimitedTask task)
{
lock (schedulingLocker)
{
RequestApproval approved = RequestApproval.Approved;
if (task.UsesSharedResources())
{
approved = sharedResourceManager.AllocateResources(task.PrioritizedLimitedTaskIdentifier
, task.SharedResources);
}
return(approved == RequestApproval.Approved);
}
}
/// <summary>
/// Starts (creates and schedules) task that is used to cooperatively cancels (and optionally pauses) user's task.
/// Is user's task used resources, resources are released.
/// This task is scheduled using default .NET scheduler.
/// </summary>
/// <param name="task">Corresponding user's task</param>
/// <param name="controlNumberOfExecutionTasksAction">Responsible for decrementing number of currently running tasks</param>
/// <param name="enablePauseAction">Responsible for pausing this callback for specific amount of time (optional)</param>
protected void StartCallback(PrioritizedLimitedTask task, Action controlNumberOfExecutionTasksAction, Action enablePauseAction = null)
=> Task.Factory.StartNew(() =>
{
Task.Delay(task.DurationInMiliseconds).Wait();
enablePauseAction?.Invoke();
task.CooperationMechanism.Cancel();
// Free shared resources
if (task.UsesSharedResources())
{
sharedResourceManager.FreeResources(task.PrioritizedLimitedTaskIdentifier, task.SharedResources);
}
controlNumberOfExecutionTasksAction.Invoke();
RunScheduling();
}, CancellationToken.None, TaskCreationOptions.None, Default);
