gecko-dev/xpcom/threads/nsThread.h
Kyle Huey a80e57e854 Bug 1204784: Do not shut the main thread down before all outstanding asynchronous thread shutdowns complete. r=froydnj
--HG--
extra : rebase_source : 9f4c8a219e2fa6dfbfec78f9f390726f2f07f683
2016-01-18 09:34:38 -08:00

217 lines
5.4 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 nsThread_h__
#define nsThread_h__
#include "mozilla/Mutex.h"
#include "nsIThreadInternal.h"
#include "nsISupportsPriority.h"
#include "nsEventQueue.h"
#include "nsThreadUtils.h"
#include "nsString.h"
#include "nsTObserverArray.h"
#include "mozilla/Attributes.h"
#include "nsAutoPtr.h"
#include "mozilla/AlreadyAddRefed.h"
namespace mozilla {
class CycleCollectedJSRuntime;
}
// A native thread
class nsThread
: public nsIThreadInternal
, public nsISupportsPriority
{
public:
NS_DECL_THREADSAFE_ISUPPORTS
NS_DECL_NSIEVENTTARGET
NS_DECL_NSITHREAD
NS_DECL_NSITHREADINTERNAL
NS_DECL_NSISUPPORTSPRIORITY
using nsIEventTarget::Dispatch;
enum MainThreadFlag
{
MAIN_THREAD,
NOT_MAIN_THREAD
};
nsThread(MainThreadFlag aMainThread, uint32_t aStackSize);
// Initialize this as a wrapper for a new PRThread.
nsresult Init();
// Initialize this as a wrapper for the current PRThread.
nsresult InitCurrentThread();
// The PRThread corresponding to this thread.
PRThread* GetPRThread()
{
return mThread;
}
// If this flag is true, then the nsThread was created using
// nsIThreadManager::NewThread.
bool ShutdownRequired()
{
return mShutdownRequired;
}
// Clear the observer list.
void ClearObservers()
{
mEventObservers.Clear();
}
void
SetScriptObserver(mozilla::CycleCollectedJSRuntime* aScriptObserver);
uint32_t
RecursionDepth() const;
void ShutdownComplete(struct nsThreadShutdownContext* aContext);
void WaitForAllAsynchronousShutdowns();
protected:
class nsChainedEventQueue;
class nsNestedEventTarget;
friend class nsNestedEventTarget;
friend class nsThreadShutdownEvent;
virtual ~nsThread();
bool ShuttingDown()
{
return mShutdownContext != nullptr;
}
static void ThreadFunc(void* aArg);
// Helper
already_AddRefed<nsIThreadObserver> GetObserver()
{
nsIThreadObserver* obs;
nsThread::GetObserver(&obs);
return already_AddRefed<nsIThreadObserver>(obs);
}
// Wrappers for event queue methods:
nsresult PutEvent(nsIRunnable* aEvent, nsNestedEventTarget* aTarget);
nsresult PutEvent(already_AddRefed<nsIRunnable>&& aEvent, nsNestedEventTarget* aTarget);
nsresult DispatchInternal(already_AddRefed<nsIRunnable>&& aEvent, uint32_t aFlags,
nsNestedEventTarget* aTarget);
struct nsThreadShutdownContext* ShutdownInternal(bool aSync);
// Wrapper for nsEventQueue that supports chaining.
class nsChainedEventQueue
{
public:
explicit nsChainedEventQueue(mozilla::Mutex& aLock)
: mNext(nullptr)
, mQueue(aLock)
{
}
bool GetEvent(bool aMayWait, nsIRunnable** aEvent,
mozilla::MutexAutoLock& aProofOfLock)
{
return mQueue.GetEvent(aMayWait, aEvent, aProofOfLock);
}
void PutEvent(nsIRunnable* aEvent, mozilla::MutexAutoLock& aProofOfLock)
{
mQueue.PutEvent(aEvent, aProofOfLock);
}
void PutEvent(already_AddRefed<nsIRunnable>&& aEvent,
mozilla::MutexAutoLock& aProofOfLock)
{
mQueue.PutEvent(mozilla::Move(aEvent), aProofOfLock);
}
bool HasPendingEvent(mozilla::MutexAutoLock& aProofOfLock)
{
return mQueue.HasPendingEvent(aProofOfLock);
}
nsChainedEventQueue* mNext;
RefPtr<nsNestedEventTarget> mEventTarget;
private:
nsEventQueue mQueue;
};
class nsNestedEventTarget final : public nsIEventTarget
{
public:
NS_DECL_THREADSAFE_ISUPPORTS
NS_DECL_NSIEVENTTARGET
nsNestedEventTarget(nsThread* aThread, nsChainedEventQueue* aQueue)
: mThread(aThread)
, mQueue(aQueue)
{
}
RefPtr<nsThread> mThread;
// This is protected by mThread->mLock.
nsChainedEventQueue* mQueue;
private:
~nsNestedEventTarget()
{
}
};
// This lock protects access to mObserver, mEvents and mEventsAreDoomed.
// All of those fields are only modified on the thread itself (never from
// another thread). This means that we can avoid holding the lock while
// using mObserver and mEvents on the thread itself. When calling PutEvent
// on mEvents, we have to hold the lock to synchronize with PopEventQueue.
mozilla::Mutex mLock;
nsCOMPtr<nsIThreadObserver> mObserver;
mozilla::CycleCollectedJSRuntime* mScriptObserver;
// Only accessed on the target thread.
nsAutoTObserverArray<nsCOMPtr<nsIThreadObserver>, 2> mEventObservers;
nsChainedEventQueue* mEvents; // never null
nsChainedEventQueue mEventsRoot;
int32_t mPriority;
PRThread* mThread;
uint32_t mNestedEventLoopDepth;
uint32_t mStackSize;
// The shutdown context for ourselves.
struct nsThreadShutdownContext* mShutdownContext;
// The shutdown contexts for any other threads we've asked to shut down.
nsTArray<nsAutoPtr<struct nsThreadShutdownContext>> mRequestedShutdownContexts;
bool mShutdownRequired;
// Set to true when events posted to this thread will never run.
bool mEventsAreDoomed;
MainThreadFlag mIsMainThread;
};
#if defined(XP_UNIX) && !defined(ANDROID) && !defined(DEBUG) && HAVE_UALARM \
&& defined(_GNU_SOURCE)
# define MOZ_CANARY
extern int sCanaryOutputFD;
#endif
#endif // nsThread_h__