/// <summary>A wrapper over DispatchSync that calls a value-producing function and returns it's result</summary>
/// <typeparam name="T">Result type</typeparam>
/// <param name="queue">The queue to execute the function on</param>
/// <param name="func">The function to execute</param>
/// <returns>The return value of func</returns>
public static T DispatchSync <T>(this IDispatchQueue queue, Func <T> func)
{
T result = default(T);
queue.DispatchSync(() => { result = func(); });
return(result);
}
//--- Constructors ---
/// <summary>
/// Create an instance of the work queue.
/// </summary>
/// <param name="handler">Dispatch action for work item Type and with completion callback.</param>
/// <param name="maxParallelism">Maximum number of items being dispatch simultaneously against the dispatch queue.</param>
/// <param name="dispatchQueue">Dispatch queue for work items.</param>
public ProcessingQueue(Action <T, Action> handler, int maxParallelism, IDispatchQueue dispatchQueue)
{
if (dispatchQueue == null)
{
throw new ArgumentNullException("dispatchQueue");
}
if (handler == null)
{
throw new ArgumentNullException("handler");
}
if ((maxParallelism <= 0) || (maxParallelism > MAX_PARALLELISM))
{
throw new ArgumentException(string.Format("maxParallelism must be between 1 and {0:#,##0}", MAX_PARALLELISM), "maxParallelism");
}
_handler = handler;
_dispatchQueue = dispatchQueue;
// prime the pending queue with dispatchers
for (var i = 0; i < maxParallelism; ++i)
{
if (!_pending.TryEnqueue(StartWorkItem))
{
throw new NotSupportedException();
}
}
}
//init
public DirectSignalProvider(IEventQueue <TKey> eventQueues, IDispatchQueue <TKey> dispatchQueues,
IMonitor <TKey> eventSink, ISignalEventQueries <TKey> eventQueries,
ISignalDispatchQueries <TKey> dispatchQueries, SenderSettings senderSettings)
: base(eventQueues, dispatchQueues, eventSink, eventQueries, dispatchQueries, senderSettings)
{
_isStarted = false;
}
//ctor
public SendDispatchCommand(IDispatchChannelRegistry <TKey> channelRegistry, ILogger logger,
IDispatchQueue <TKey> dispatchQueue, IMonitor <TKey> monitor)
{
_channelRegistry = channelRegistry;
_logger = logger;
_dispatchQueue = dispatchQueue;
_monitor = monitor;
}
/// <summary>
/// Create a new environment.
/// </summary>
/// <param name="dispatchQueue">Dispatch queue to use for the environment.</param>
/// <param name="taskTimerFactory"><see cref="TaskTimer"/> factory to use for the environment.</param>
/// <returns>A new <see cref="TaskEnv"/> instance.</returns>
public static TaskEnv New(IDispatchQueue dispatchQueue, TaskTimerFactory taskTimerFactory)
{
if (dispatchQueue == null)
{
throw new ArgumentNullException("dispatchQueue");
}
return(new TaskEnv(dispatchQueue, taskTimerFactory));
}
public DatabaseDispatchProvider(IDispatchQueue <TKey> dispatchQueues, IMonitor <TKey> eventSink, SenderSettings senderSettings,
IDispatchChannelRegistry <TKey> dispatcherRegistry, ISignalDispatchQueries <TKey> dispatchQueries,
ILogger logger, IChangeNotifier <SignalDispatch <TKey> > changeNotifier,
ILockTracker <TKey> lockTracker, IConsolidationLockTracker <TKey> consolidationLockTracker)
: this(dispatchQueues, eventSink, senderSettings, dispatcherRegistry, dispatchQueries, logger, lockTracker, consolidationLockTracker)
{
_changeNotifier = changeNotifier;
}
/// <summary>
/// Clone the current task environment with a provided dispatch queue.
/// </summary>
/// <param name="dispatchQueue">Dispatch queue to use for the environment.</param>
/// <returns>A new <see cref="TaskEnv"/> instance.</returns>
public static TaskEnv Clone(IDispatchQueue dispatchQueue)
{
if (dispatchQueue == null)
{
throw new ArgumentNullException("dispatchQueue");
}
return(new TaskEnv(_currentEnv, dispatchQueue, CurrentTimerFactoryOrNull));
}
public TimerQueue(IDispatchQueue dispatchQueue, IDispatcher dispatcher)
{
mDispatchQueue = dispatchQueue ?? throw new ArgumentNullException("dispatchQueue");
mDispatcher = dispatcher ?? throw new ArgumentNullException("dispatcher");
mTimer = new Timer(OnTimerExecute);
mScheduleWorkForExecutionCallback = OnScheduleWorkForExecution;
}
//ctor
public CheckConsolidationLockExpirationCommand(IConsolidationLockTracker <TKey> lockTracker,
IConsolidationLockQueries <TKey> consolidationLockQueries, SenderSettings settings,
IDispatchQueue <TKey> dispatchQueue)
{
_consolidationLockTracker = lockTracker;
_consolidationLockQueries = consolidationLockQueries;
_settings = settings;
_dispatchQueue = dispatchQueue;
}
/// <summary>
/// Enqueue a callback as a work item to be invoked with a provided <see cref="TaskEnv"/>.
/// </summary>
/// <typeparam name="T">Result value type of callback.</typeparam>
/// <param name="dispatchQueue">DispatchQueue to enqueue work into.</param>
/// <param name="callback">Work item callback.</param>
/// <param name="env">Environment for work item invocation.</param>
/// <param name="result">Synchronization handle for work item.</param>
/// <returns>The synchronization handle provided to the method.</returns>
public static Result <T> QueueWorkItemWithEnv <T>(this IDispatchQueue dispatchQueue, Func <T> callback, TaskEnv env, Result <T> result)
{
if (env == null)
{
throw new ArgumentException("env");
}
dispatchQueue.QueueWorkItem(env.MakeAction(callback, result));
return(result);
}
public void PinTo(IDispatchQueue dispatchQueue)
{
// TODO 2.0 (steveb): remove implementation
if (_dispatchQueue != null)
{
throw new InvalidOperationException("RendezVousEvent is already pinned to an IDispatchQueue");
}
_dispatchQueue = dispatchQueue;
}
//init
public BaseSignalProvider(IEventQueue <TKey> eventQueue, IDispatchQueue <TKey> dispatchQueue, IMonitor <TKey> eventSink,
ISignalEventQueries <TKey> eventQueries, ISignalDispatchQueries <TKey> dispatchQueries, SenderSettings senderSettings)
{
_eventQueue = eventQueue;
_dispatchQueue = dispatchQueue;
_monitor = eventSink;
_eventQueries = eventQueries;
_dispatchQueries = dispatchQueries;
_senderSettings = senderSettings;
}
//ctor
public ConsolidateDispatchCommand(ILogger logger, ISignalDispatchQueries <TKey> signalDispatchQueries,
IDispatchQueue <TKey> dispatchQueue, IEnumerable <ITemplateDataConsolidator> consolidators,
IEventSettingsQueries <TKey> eventSettingsQueries)
{
_logger = logger;
_signalDispatchQueries = signalDispatchQueries;
_dispatchQueue = dispatchQueue;
_consolidators = consolidators.ToArray();
_eventSettingsQueries = eventSettingsQueries;
}
private static void FibonacciThreadPool(IDispatchQueue stp, int n, TimeSpan delay, out int value, out TimeSpan elapsed)
{
_log.Debug("FibonacciThreadPool");
var sw = Stopwatch.StartNew();
value = Fibonacci(stp, n, delay, new Result <int>(TimeSpan.MaxValue, TaskEnv.New(stp))).Wait();
sw.Stop();
elapsed = sw.Elapsed;
}
//init
public SignalServiceInstanceProvider(IEventQueue <TKey> eventQueues, IDispatchQueue <TKey> dispatchQueues,
IMonitor <TKey> eventSink, ISignalEventQueries <TKey> eventQueries,
ISignalDispatchQueries <TKey> dispatchQueries, SenderSettings senderSettings)
{
_eventQueues = eventQueues;
_dispatchQueues = dispatchQueues;
_monitor = eventSink;
_eventQueries = eventQueries;
_dispatchQueries = dispatchQueries;
_senderSettings = senderSettings;
}
//--- Class Methods ---
public static bool TryQueueWorkItem(IDispatchQueue queue, Action callback)
{
DispatchThread current = CurrentThread;
if ((current != null) && ReferenceEquals(AsyncUtil.CurrentDispatchQueue, queue))
{
// NOTE (steveb): next call can never fail since we're calling the queue work-item method of the current thread
current.QueueWorkItem(callback);
return(true);
}
return(false);
}
public static void DispatchSync(this IDispatchQueue queue, object?context, WaitCallback?work)
{
TaskCompletionSource <object?> tcs = new TaskCompletionSource <object?>();
queue.DispatchAsync(context, (context) =>
{
work?.Invoke(context);
tcs.SetResult(null);
});
tcs.Task.Wait();
}
private TaskEnv(TaskEnv env, IDispatchQueue dispatchQueue, TaskTimerFactory taskTimerFactory)
{
if (env != null)
{
foreach (var entry in env)
{
var cloneable = entry.Value as ITaskLifespan;
Add(entry.Key, cloneable == null ? entry.Value : cloneable.Clone());
}
}
_taskTimerFactory = taskTimerFactory;
_dispatchQueue = (dispatchQueue is ImmediateDispatchQueue) ? null : dispatchQueue;
}
/// <summary>A wrapper over DispatchAsync that calls a value-producing function on the queue and returns it's result via a Task</summary>
/// <remarks>Note: the task "completes" on the dispatch queue, so if you use ConfigureAwait(false) or
/// TaskContinuationOptions.ExecuteSychronously, you will still be running on the dispatch queue</remarks>
/// <typeparam name="T">Result type</typeparam>
/// <param name="queue">The queue to execute the function on</param>
/// <param name="func">The function to execute</param>
/// <returns>A task wrapping the return value (or exception) the func produced.</returns>
public static Task <T> DispatchAsync <T>(this IDispatchQueue queue, Func <T> func)
{
var tcs = new TaskCompletionSource <T>();
queue.DispatchAsync(() => {
try {
tcs.SetResult(func());
}
catch (Exception e) {
tcs.TrySetException(e);
}
});
return(tcs.Task);
}
//init
public DispatchProcessor(SenderState <TKey> hubState, IDispatchQueue <TKey> dispatchQueue,
ILogger logger, SenderSettings senderSettings, IDispatchChannelRegistry <TKey> channelRegistry,
IEnumerable <IDispatchProcessingCommand <TKey> > processingCommands)
: base(logger)
{
_hubState = hubState;
_dispatchQueue = dispatchQueue;
_channelRegistry = channelRegistry;
_processingCommands = processingCommands
.OrderBy(x => x.Order)
.ToArray();
MaxParallelItems = senderSettings.MaxParallelDispatchesProcessed;
}
//init
public EventProcessor(SenderState <TKey> hubState, IMonitor <TKey> eventSink
, ILogger logger, SenderSettings senderSettings
, IEventQueue <TKey> eventQueue, IDispatchQueue <TKey> dispatchQueue
, IEventHandlerRegistry <TKey> handlerRegistry, IEventSettingsQueries <TKey> eventSettingsQueries)
: base(logger)
{
_hubState = hubState;
_monitor = eventSink;
_eventQueue = eventQueue;
_dispatchQueue = dispatchQueue;
_handlerRegistry = handlerRegistry;
_eventSettingsQueries = eventSettingsQueries;
MaxParallelItems = senderSettings.MaxParallelEventsProcessed;
}
public NewRoomRequestHandler(
IDispatchQueue centralDispatchQueue,
IRoomRepository roomRepository,
IRoomFactory roomFactory,
IObserver <TransceiverMetadataUpdatedEvent> transceiverMetadataUpdatedObserver)
{
_centralDispatchQueue = centralDispatchQueue
?? throw new ArgumentNullException(nameof(centralDispatchQueue));
_roomRepository = roomRepository
?? throw new ArgumentNullException(nameof(roomRepository));
_roomFactory = roomFactory
?? throw new ArgumentNullException(nameof(roomFactory));
_transceiverMetadataUpdatedObserver = transceiverMetadataUpdatedObserver
?? throw new ArgumentNullException(nameof(transceiverMetadataUpdatedObserver));
}
//--- Constructors ---
static Async()
{
if (!int.TryParse(System.Configuration.ConfigurationManager.AppSettings["threadpool-min"], out _minThreads))
{
_minThreads = 4;
}
if (!int.TryParse(System.Configuration.ConfigurationManager.AppSettings["threadpool-max"], out _maxThreads))
{
_maxThreads = 200;
}
int maxStackSize;
if (int.TryParse(System.Configuration.ConfigurationManager.AppSettings["max-stacksize"], out maxStackSize))
{
_maxStackSize = maxStackSize;
}
// check which global dispatch queue implementation to use
int dummy;
switch (System.Configuration.ConfigurationManager.AppSettings["threadpool"])
{
default:
case "elastic":
ThreadPool.GetMinThreads(out dummy, out _minPorts);
ThreadPool.GetMaxThreads(out dummy, out _maxPorts);
_log.DebugFormat("Using ElasticThreadPool with {0}min / {1}max", _minThreads, _maxThreads);
var elasticThreadPool = new ElasticThreadPool(_minThreads, _maxThreads);
GlobalDispatchQueue = elasticThreadPool;
_inplaceActivation = false;
_availableThreadsCallback = delegate(out int threads, out int ports) {
int dummy2;
ThreadPool.GetAvailableThreads(out dummy2, out ports);
threads = elasticThreadPool.MaxParallelThreads - elasticThreadPool.ThreadCount;
};
break;
case "legacy":
ThreadPool.GetMinThreads(out dummy, out _minPorts);
ThreadPool.GetMaxThreads(out dummy, out _maxPorts);
ThreadPool.SetMinThreads(_minThreads, _minPorts);
ThreadPool.SetMaxThreads(_maxThreads, _maxPorts);
_log.Debug("Using LegacyThreadPool");
GlobalDispatchQueue = LegacyThreadPool.Instance;
_availableThreadsCallback = ThreadPool.GetAvailableThreads;
break;
}
}
//init
public Sender(SenderState <TKey> hubState, IEventQueue <TKey> eventQueue,
IDispatchQueue <TKey> dispatchQueue, IEnumerable <IRegularJob> regularJobs,
IEnumerable <ISignalProviderControl> signalEndpoints)
{
_hubState = hubState;
_regularJobs = regularJobs.ToList();
_eventQueue = eventQueue;
_dispatchQueue = dispatchQueue;
_signalEndpoints = signalEndpoints.ToList();
_regularJobTimers = _regularJobs.Select(x => new NonReentrantTimer(x.Tick
, NotificationsConstants.REGULAR_JOB_TICK_INTERVAL, intervalFromCallbackStarted: false))
.ToList();
_stopMonitorTimer = new NonReentrantTimer(StopTimers
, NotificationsConstants.REGULAR_JOB_TICK_INTERVAL, intervalFromCallbackStarted: false);
_stopEventHandle = new ManualResetEventSlim(false);
}
//init
public DatabaseDispatchProvider(IDispatchQueue <TKey> dispatchQueue, IMonitor <TKey> eventSink, SenderSettings senderSettings,
IDispatchChannelRegistry <TKey> dispatcherRegistry, ISignalDispatchQueries <TKey> dispatchQueries, ILogger logger,
ILockTracker <TKey> lockTracker, IConsolidationLockTracker <TKey> consolidationLockTracker)
{
_dispatchQueue = dispatchQueue;
_monitor = eventSink;
_dispatcherRegistry = dispatcherRegistry;
_dispatchQueries = dispatchQueries;
_logger = logger;
_lockTracker = lockTracker;
_consolidationLockTracker = consolidationLockTracker;
_senderSettings = senderSettings;
QueryPeriod = senderSettings.DatabaseSignalProviderQueryPeriod;
ItemsQueryCount = senderSettings.DatabaseSignalProviderItemsQueryCount;
MaxFailedAttempts = senderSettings.DatabaseSignalProviderItemsMaxFailedAttempts;
}
// (yurig): This method has been intentionally split from DispatchLoop()
// result.Block() inside causes Result<DispatchWorkItem> to never be disposed.
// By moving it into its own method we ensure its garbage collection as it is
// popped off the stack. Do NOT inline this method into DispatchLoop().
private bool GetNextWorkItem(out Action callback)
{
if (!_inbox.TryPop(out callback))
{
var result = new Result <DispatchWorkItem>(TimeSpan.MaxValue);
// reset the dispatch queue for this thread
AsyncUtil.CurrentDispatchQueue = null;
_queue = null;
// check if thread is associated with a host already
if (_host == null)
{
// NOTE (steveb): this is a brand new thread without a host yet
// return the thread to the dispatch scheduler
DispatchThreadScheduler.ReleaseThread(this, result);
}
else
{
// request another work-item
_host.RequestWorkItem(this, result);
}
// block until a work item is available
result.Block();
// check if we received a work item or an exception to shutdown
if (result.HasException && (result.Exception is DispatchThreadShutdownException))
{
// time to shut down
_log.DebugFormat("DispatchThread #{0} destroyed", _id);
return(false);
}
callback = result.Value.WorkItem;
_queue = result.Value.DispatchQueue;
// TODO (steveb): handle the weird case where _queue is null
// set the dispatch queue for this thread
AsyncUtil.CurrentDispatchQueue = _queue;
}
return(true);
}
private bool TryQueueWorkItem(int priority, Action callback)
{
if (_disposed)
{
throw new ObjectDisposedException("ElasticThreadPool has already been disposed");
}
// check if we can enqueue work-item into current dispatch thread
IDispatchQueue queue = this[priority];
if (DispatchThread.TryQueueWorkItem(queue, callback))
{
return(true);
}
// check if there are available threads to which the work-item can be given to
KeyValuePair <DispatchThread, Result <DispatchWorkItem> > entry;
if (_reservedThreads.TryPop(out entry))
{
lock (_syncRoot) {
RegisterThread("new item", entry.Key);
}
// found an available thread, let's resume it with the work-item
entry.Value.Return(new DispatchWorkItem(callback, queue));
return(true);
}
// no threads available, keep work-item for later
if (!_inbox.TryEnqueue(priority, callback))
{
return(false);
}
// check if we need to request a thread to kick things off
if (ThreadCount == 0)
{
((IDispatchHost)this).IncreaseThreadCount("request first thread");
}
return(true);
}
private static Result <int> Fibonacci(IDispatchQueue stp, int n, TimeSpan delay, Result <int> result)
{
if (!ReferenceEquals(result.Env.DispatchQueue, stp))
{
_log.Error(string.Format("ERROR: wrong task env {0}, expected {1}.", result.Env.DispatchQueue, stp));
}
stp.QueueWorkItem(delegate {
Interlocked.Increment(ref _counter);
switch (n)
{
case 0:
if (delay > TimeSpan.Zero)
{
Thread.Sleep(delay);
}
result.Return(0);
break;
case 1:
if (delay > TimeSpan.Zero)
{
Thread.Sleep(delay);
}
result.Return(1);
break;
default:
Result <int> a = Fibonacci(stp, n - 1, delay, new Result <int>(TimeSpan.MaxValue, TaskEnv.New(stp)));
Result <int> b = Fibonacci(stp, n - 2, delay, new Result <int>(TimeSpan.MaxValue, TaskEnv.New(stp)));
new AResult[] { a, b }.Join(new Result(TimeSpan.MaxValue, TaskEnv.New(stp))).WhenDone(_ => {
if (!ReferenceEquals(AsyncUtil.CurrentDispatchQueue, stp))
{
_log.Error(string.Format("ERROR: wrong queue {0}, expected {1}.", AsyncUtil.CurrentDispatchQueue, stp));
}
result.Return(a.Value + b.Value);
});
break;
}
});
return(result);
}
/// <summary>
/// Enqueue a callback as a work item to be invoked with the current <see cref="TaskEnv"/>.
/// </summary>
/// <typeparam name="T">Result value type of callback.</typeparam>
/// <param name="dispatchQueue">DispatchQueue to enqueue work into.</param>
/// <param name="callback">Work item callback.</param>
/// <param name="result">Synchronization handle for work item.</param>
/// <returns>The synchronization handle provided to the method.</returns>
public static Result <T> QueueWorkItemWithCurrentEnv <T>(this IDispatchQueue dispatchQueue, Func <T> callback, Result <T> result)
{
var current = TaskEnv.CurrentOrNull;
if (current != null)
{
return(dispatchQueue.QueueWorkItemWithEnv(callback, current, result));
}
if (result != null)
{
dispatchQueue.QueueWorkItem(delegate() {
try {
result.Return(callback());
} catch (Exception e) {
result.Throw(e);
}
});
return(result);
}
dispatchQueue.QueueWorkItem(() => callback());
return(null);
}
/// <summary>
/// Enqueue a callback as a work item to be invoked with the current <see cref="TaskEnv"/>.
/// </summary>
/// <param name="dispatchQueue">DispatchQueue to enqueue work into.</param>
/// <param name="callback">Work item callback.</param>
/// <param name="result">Synchronization handle for work item.</param>
/// <returns>The synchronization handle provided to the method.</returns>
public static Result QueueWorkItemWithCurrentEnv(this IDispatchQueue dispatchQueue, Action callback, Result result)
{
var current = TaskEnv.CurrentOrNull;
if (current != null)
{
return(dispatchQueue.QueueWorkItemWithEnv(callback, current, result));
}
if (result != null)
{
dispatchQueue.QueueWorkItem(() => {
try {
callback();
result.Return();
} catch (Exception e) {
result.Throw(e);
}
});
return(result);
}
dispatchQueue.QueueWorkItem(callback);
return(null);
}
//--- Constructors ---
/// <summary>
/// Create new work-item instance.
/// </summary>
/// <param name="workitem">Work-item callback.</param>
/// <param name="queue">Dispatch queue associated with work-item.</param>
public DispatchWorkItem(Action workitem, IDispatchQueue queue)
{
this.WorkItem = workitem;
this.DispatchQueue = queue;
}
private static void FibonacciThreadPool(IDispatchQueue stp, int n, TimeSpan delay, out int value, out TimeSpan elapsed)
{
_log.Debug("FibonacciThreadPool");
var sw = Stopwatch.StartNew();
value = Fibonacci(stp, n, delay, new Result<int>(TimeSpan.MaxValue, TaskEnv.New(stp))).Wait();
sw.Stop();
elapsed = sw.Elapsed;
}
private static Result<int> Fibonacci(IDispatchQueue stp, int n, TimeSpan delay, Result<int> result)
{
if(!ReferenceEquals(result.Env.DispatchQueue, stp)) {
_log.Error(string.Format("ERROR: wrong task env {0}, expected {1}.", result.Env.DispatchQueue, stp));
}
stp.QueueWorkItem(delegate {
Interlocked.Increment(ref _counter);
switch(n) {
case 0:
if(delay > TimeSpan.Zero) {
Thread.Sleep(delay);
}
result.Return(0);
break;
case 1:
if(delay > TimeSpan.Zero) {
Thread.Sleep(delay);
}
result.Return(1);
break;
default:
Result<int> a = Fibonacci(stp, n - 1, delay, new Result<int>(TimeSpan.MaxValue, TaskEnv.New(stp)));
Result<int> b = Fibonacci(stp, n - 2, delay, new Result<int>(TimeSpan.MaxValue, TaskEnv.New(stp)));
new AResult[] { a, b }.Join(new Result(TimeSpan.MaxValue, TaskEnv.New(stp))).WhenDone(_ => {
if(!ReferenceEquals(Async.CurrentDispatchQueue, stp)) {
_log.Error(string.Format("ERROR: wrong queue {0}, expected {1}.", Async.CurrentDispatchQueue, stp));
}
result.Return(a.Value + b.Value);
});
break;
}
});
return result;
}
public void PinTo(IDispatchQueue dispatchQueue)
{
// TODO 2.0 (steveb): remove implementation
if(_dispatchQueue != null) {
throw new InvalidOperationException("RendezVousEvent is already pinned to an IDispatchQueue");
}
_dispatchQueue = dispatchQueue;
}
// (yurig): This method has been intentionally split from DispatchLoop()
// result.Block() inside causes Result<DispatchWorkItem> to never be disposed.
// By moving it into its own method we ensure its garbage collection as it is
// popped off the stack. Do NOT inline this method into DispatchLoop().
private bool GetNextWorkItem(out Action callback)
{
if(!_inbox.TryPop(out callback)) {
var result = new Result<DispatchWorkItem>(TimeSpan.MaxValue);
// reset the dispatch queue for this thread
AsyncUtil.CurrentDispatchQueue = null;
_queue = null;
// check if thread is associated with a host already
if(_host == null) {
// NOTE (steveb): this is a brand new thread without a host yet
// return the thread to the dispatch scheduler
DispatchThreadScheduler.ReleaseThread(this, result);
} else {
// request another work-item
_host.RequestWorkItem(this, result);
}
// block until a work item is available
result.Block();
// check if we received a work item or an exception to shutdown
if(result.HasException && (result.Exception is DispatchThreadShutdownException)) {
// time to shut down
_log.DebugFormat("DispatchThread #{0} destroyed", _id);
return false;
}
callback = result.Value.WorkItem;
_queue = result.Value.DispatchQueue;
// TODO (steveb): handle the weird case where _queue is null
// set the dispatch queue for this thread
AsyncUtil.CurrentDispatchQueue = _queue;
}
return true;
}
private void DispatchLoop()
{
// set thread-local self-reference
CurrentThread = this;
// begin thread loop
try {
while(true) {
// check if queue has a work-item
Action callback;
if(!_inbox.TryPop(out callback)) {
var result = new Result<DispatchWorkItem>(TimeSpan.MaxValue);
// reset the dispatch queue for this thread
Async.CurrentDispatchQueue = null;
// check if thread is associated with a host already
if(_host == null) {
// NOTE (steveb): this is a brand new thread without a host yet
// return the thread to the dispatch scheduler
DispatchThreadScheduler.ReleaseThread(this, result);
} else {
// request another work-item
_host.RequestWorkItem(this, result);
}
// block until a work item is available
result.Block();
// check if we received a work item or an exception to shutdown
if(result.HasException && (result.Exception is DispatchThreadShutdownException)) {
// time to shut down
_log.DebugFormat("DispatchThread #{0} destroyed", _id);
return;
}
callback = result.Value.WorkItem;
_queue = result.Value.DispatchQueue;
// TODO (steveb): handle the weird case where _queue is null
// set the dispatch queue for this thread
Async.CurrentDispatchQueue = _queue;
}
// execute work-item
if(callback != null) {
try {
callback();
} catch(Exception e) {
_log.Warn("an unhandled exception occurred while executing the work-item", e);
}
}
}
} catch(Exception e) {
// something went wrong that shouldn't have!
_log.ErrorExceptionMethodCall(e, string.Format("DispatchLoop #{0}: FATAL ERROR", _id));
// TODO (steveb): tell _host about untimely exit; post items in queue to host inbox (o/w we lose them)
} finally {
CurrentThread = null;
}
}
//--- Class Methods ---
public static bool TryQueueWorkItem(IDispatchQueue queue, Action callback)
{
DispatchThread current = CurrentThread;
if((current != null) && ReferenceEquals(Async.CurrentDispatchQueue, queue)) {
// NOTE (steveb): next call can never fail since we're calling the queue work-item method of the current thread
current.QueueWorkItem(callback);
return true;
}
return false;
}
