131 lines
5.3 KiB
C++
131 lines
5.3 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
|
|
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
|
|
/* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
#ifndef mozilla_SynchronizedEventQueue_h
|
|
#define mozilla_SynchronizedEventQueue_h
|
|
|
|
#include "mozilla/AlreadyAddRefed.h"
|
|
#include "mozilla/EventQueue.h"
|
|
#include "mozilla/MemoryReporting.h"
|
|
#include "mozilla/Mutex.h"
|
|
#include "nsIThreadInternal.h"
|
|
#include "nsCOMPtr.h"
|
|
#include "nsTObserverArray.h"
|
|
|
|
class nsIEventTarget;
|
|
class nsISerialEventTarget;
|
|
class nsIThreadObserver;
|
|
|
|
namespace mozilla {
|
|
|
|
// A SynchronizedEventQueue is an abstract class for event queues that can be
|
|
// used across threads. A SynchronizedEventQueue implementation will typically
|
|
// use locks and condition variables to guarantee consistency. The methods of
|
|
// SynchronizedEventQueue are split between ThreadTargetSink (which contains
|
|
// methods for posting events) and SynchronizedEventQueue (which contains
|
|
// methods for getting events). This split allows event targets (specifically
|
|
// ThreadEventTarget) to use a narrow interface, since they only need to post
|
|
// events.
|
|
//
|
|
// ThreadEventQueue is the canonical implementation of
|
|
// SynchronizedEventQueue. When Quantum DOM is implemented, we will use a
|
|
// different synchronized queue on the main thread, SchedulerEventQueue, which
|
|
// will handle the cooperative threading model.
|
|
|
|
class ThreadTargetSink {
|
|
public:
|
|
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ThreadTargetSink)
|
|
|
|
virtual bool PutEvent(already_AddRefed<nsIRunnable>&& aEvent,
|
|
EventQueuePriority aPriority) = 0;
|
|
|
|
// After this method is called, no more events can be posted.
|
|
virtual void Disconnect(const MutexAutoLock& aProofOfLock) = 0;
|
|
|
|
virtual nsresult RegisterShutdownTask(nsITargetShutdownTask* aTask) = 0;
|
|
virtual nsresult UnregisterShutdownTask(nsITargetShutdownTask* aTask) = 0;
|
|
|
|
size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) {
|
|
return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
|
|
}
|
|
|
|
// Not const because overrides may need to take a lock
|
|
virtual size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) = 0;
|
|
|
|
protected:
|
|
virtual ~ThreadTargetSink() = default;
|
|
};
|
|
|
|
class SynchronizedEventQueue : public ThreadTargetSink {
|
|
public:
|
|
virtual already_AddRefed<nsIRunnable> GetEvent(
|
|
bool aMayWait, mozilla::TimeDuration* aLastEventDelay = nullptr) = 0;
|
|
virtual bool HasPendingEvent() = 0;
|
|
|
|
// This method atomically checks if there are pending events and, if there are
|
|
// none, forbids future events from being posted. It returns true if there
|
|
// were no pending events.
|
|
virtual bool ShutdownIfNoPendingEvents() = 0;
|
|
|
|
// These methods provide access to an nsIThreadObserver, whose methods are
|
|
// called when posting and processing events. SetObserver should only be
|
|
// called on the thread that processes events. GetObserver can be called from
|
|
// any thread. GetObserverOnThread must be used from the thread that processes
|
|
// events; it does not acquire a lock.
|
|
virtual already_AddRefed<nsIThreadObserver> GetObserver() = 0;
|
|
virtual already_AddRefed<nsIThreadObserver> GetObserverOnThread() = 0;
|
|
virtual void SetObserver(nsIThreadObserver* aObserver) = 0;
|
|
|
|
void AddObserver(nsIThreadObserver* aObserver);
|
|
void RemoveObserver(nsIThreadObserver* aObserver);
|
|
const nsTObserverArray<nsCOMPtr<nsIThreadObserver>>& EventObservers();
|
|
|
|
size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) override {
|
|
// Normally we'd return
|
|
// mEventObservers.ShallowSizeOfExcludingThis(aMallocSizeOf); However,
|
|
// mEventObservers may be being mutated on another thread, and we don't lock
|
|
// around access, so locking here wouldn't help. They're small, so
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* This method causes any events currently enqueued on the thread to be
|
|
* suppressed until PopEventQueue is called, and any event dispatched to this
|
|
* thread's nsIEventTarget will queue as well. Calls to PushEventQueue may be
|
|
* nested and must each be paired with a call to PopEventQueue in order to
|
|
* restore the original state of the thread. The returned nsIEventTarget may
|
|
* be used to push events onto the nested queue. Dispatching will be disabled
|
|
* once the event queue is popped. The thread will only ever process pending
|
|
* events for the innermost event queue. Must only be called on the target
|
|
* thread.
|
|
*/
|
|
virtual already_AddRefed<nsISerialEventTarget> PushEventQueue() = 0;
|
|
|
|
/**
|
|
* Revert a call to PushEventQueue. When an event queue is popped, any events
|
|
* remaining in the queue are appended to the elder queue. This also causes
|
|
* the nsIEventTarget returned from PushEventQueue to stop dispatching events.
|
|
* Must only be called on the target thread, and with the innermost event
|
|
* queue.
|
|
*/
|
|
virtual void PopEventQueue(nsIEventTarget* aTarget) = 0;
|
|
|
|
/**
|
|
* Flush the list of shutdown tasks which were previously registered. After
|
|
* this is called, new shutdown tasks cannot be registered.
|
|
*/
|
|
virtual void RunShutdownTasks() = 0;
|
|
|
|
protected:
|
|
virtual ~SynchronizedEventQueue() = default;
|
|
|
|
private:
|
|
nsTObserverArray<nsCOMPtr<nsIThreadObserver>> mEventObservers;
|
|
};
|
|
|
|
} // namespace mozilla
|
|
|
|
#endif // mozilla_SynchronizedEventQueue_h
|