forked from mirrors/gecko-dev
		
	
		
			
				
	
	
		
			137 lines
		
	
	
	
		
			4.6 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			137 lines
		
	
	
	
		
			4.6 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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| /* vim: set ts=8 sts=2 et sw=2 tw=80: */
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| /* This Source Code Form is subject to the terms of the Mozilla Public
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|  * License, v. 2.0. If a copy of the MPL was not distributed with this
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|  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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| 
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| #include "ThreadEventTarget.h"
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| #include "mozilla/ThreadEventQueue.h"
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| 
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| #include "LeakRefPtr.h"
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| #include "mozilla/SpinEventLoopUntil.h"
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| #include "mozilla/TimeStamp.h"
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| #include "nsComponentManagerUtils.h"
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| #include "nsITimer.h"
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| #include "nsThreadManager.h"
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| #include "nsThreadSyncDispatch.h"
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| #include "nsThreadUtils.h"
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| #include "nsXPCOMPrivate.h"  // for gXPCOMThreadsShutDown
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| #include "ThreadDelay.h"
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| 
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| #ifdef MOZ_TASK_TRACER
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| #  include "GeckoTaskTracer.h"
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| #  include "TracedTaskCommon.h"
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| using namespace mozilla::tasktracer;
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| #endif
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| 
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| using namespace mozilla;
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| 
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| ThreadEventTarget::ThreadEventTarget(ThreadTargetSink* aSink,
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|                                      bool aIsMainThread)
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|     : mSink(aSink), mIsMainThread(aIsMainThread) {
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|   mThread = PR_GetCurrentThread();
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| }
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| 
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| void ThreadEventTarget::SetCurrentThread(PRThread* aThread) {
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|   mThread = aThread;
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| }
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| 
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| void ThreadEventTarget::ClearCurrentThread() { mThread = nullptr; }
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| 
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| NS_IMPL_ISUPPORTS(ThreadEventTarget, nsIEventTarget, nsISerialEventTarget)
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| 
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| NS_IMETHODIMP
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| ThreadEventTarget::DispatchFromScript(nsIRunnable* aRunnable, uint32_t aFlags) {
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|   return Dispatch(do_AddRef(aRunnable), aFlags);
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| }
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| 
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| NS_IMETHODIMP
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| ThreadEventTarget::Dispatch(already_AddRefed<nsIRunnable> aEvent,
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|                             uint32_t aFlags) {
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|   // We want to leak the reference when we fail to dispatch it, so that
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|   // we won't release the event in a wrong thread.
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|   LeakRefPtr<nsIRunnable> event(std::move(aEvent));
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|   if (NS_WARN_IF(!event)) {
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|     return NS_ERROR_INVALID_ARG;
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|   }
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| 
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|   if (gXPCOMThreadsShutDown && !mIsMainThread) {
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|     NS_ASSERTION(false, "Failed Dispatch after xpcom-shutdown-threads");
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|     return NS_ERROR_ILLEGAL_DURING_SHUTDOWN;
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|   }
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| 
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| #ifdef MOZ_TASK_TRACER
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|   nsCOMPtr<nsIRunnable> tracedRunnable = CreateTracedRunnable(event.take());
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|   (static_cast<TracedRunnable*>(tracedRunnable.get()))->DispatchTask();
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|   // XXX tracedRunnable will always leaked when we fail to disptch.
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|   event = tracedRunnable.forget();
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| #endif
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| 
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|   LogRunnable::LogDispatch(event.get());
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| 
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|   if (aFlags & DISPATCH_SYNC) {
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|     nsCOMPtr<nsIEventTarget> current = GetCurrentEventTarget();
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|     if (NS_WARN_IF(!current)) {
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|       return NS_ERROR_NOT_AVAILABLE;
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|     }
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| 
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|     // XXX we should be able to do something better here... we should
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|     //     be able to monitor the slot occupied by this event and use
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|     //     that to tell us when the event has been processed.
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| 
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|     RefPtr<nsThreadSyncDispatch> wrapper =
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|         new nsThreadSyncDispatch(current.forget(), event.take());
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|     bool success = mSink->PutEvent(do_AddRef(wrapper),
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|                                    EventQueuePriority::Normal);  // hold a ref
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|     if (!success) {
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|       // PutEvent leaked the wrapper runnable object on failure, so we
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|       // explicitly release this object once for that. Note that this
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|       // object will be released again soon because it exits the scope.
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|       wrapper.get()->Release();
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|       return NS_ERROR_UNEXPECTED;
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|     }
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| 
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|     // Allows waiting; ensure no locks are held that would deadlock us!
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|     SpinEventLoopUntil(
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|         [&, wrapper]() -> bool { return !wrapper->IsPending(); });
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| 
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|     return NS_OK;
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|   }
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| 
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|   NS_ASSERTION(aFlags == NS_DISPATCH_NORMAL || aFlags == NS_DISPATCH_AT_END,
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|                "unexpected dispatch flags");
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|   if (!mSink->PutEvent(event.take(), EventQueuePriority::Normal)) {
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|     return NS_ERROR_UNEXPECTED;
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|   }
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|   // Delay to encourage the receiving task to run before we do work.
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|   DelayForChaosMode(ChaosFeature::TaskDispatching, 1000);
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|   return NS_OK;
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| }
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| 
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| NS_IMETHODIMP
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| ThreadEventTarget::DelayedDispatch(already_AddRefed<nsIRunnable> aEvent,
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|                                    uint32_t aDelayMs) {
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|   nsCOMPtr<nsIRunnable> event = aEvent;
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|   NS_ENSURE_TRUE(!!aDelayMs, NS_ERROR_UNEXPECTED);
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| 
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|   RefPtr<DelayedRunnable> r =
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|       new DelayedRunnable(do_AddRef(this), event.forget(), aDelayMs);
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|   nsresult rv = r->Init();
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|   NS_ENSURE_SUCCESS(rv, rv);
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| 
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|   return Dispatch(r.forget(), NS_DISPATCH_NORMAL);
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| }
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| 
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| NS_IMETHODIMP
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| ThreadEventTarget::IsOnCurrentThread(bool* aIsOnCurrentThread) {
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|   *aIsOnCurrentThread = IsOnCurrentThread();
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|   return NS_OK;
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| }
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| 
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| NS_IMETHODIMP_(bool)
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| ThreadEventTarget::IsOnCurrentThreadInfallible() {
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|   // This method is only going to be called if `mThread` is null, which
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|   // only happens when the thread has exited the event loop.  Therefore, when
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|   // we are called, we can never be on this thread.
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|   return false;
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| }
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