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 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

 /* vim:set ts=2 sw=2 sts=2 et cindent: */

 /* 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"

 // 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

   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(); }

   static nsresult

   SetMainThreadObserver(nsIThreadObserver* aObserver);

 protected:

   static nsIThreadObserver* sMainThreadObserver;

   class nsChainedEventQueue;

   class nsNestedEventTarget;

   friend class nsNestedEventTarget;

   friend class nsThreadShutdownEvent;

   virtual ~nsThread();

   bool ShuttingDown() { return mShutdownContext != nullptr; }

   static void ThreadFunc(void *arg);

   // Helper

   already_AddRefed<nsIThreadObserver> GetObserver() {

     nsIThreadObserver *obs;

     nsThread::GetObserver(&obs);

     return already_AddRefed<nsIThreadObserver>(obs);

   }

   // Wrappers for event queue methods:

   bool GetEvent(bool mayWait, nsIRunnable **event) {

     return mEvents->GetEvent(mayWait, event);

   }

   nsresult PutEvent(nsIRunnable *event, nsNestedEventTarget *target);

   nsresult DispatchInternal(nsIRunnable *event, uint32_t flags,

                             nsNestedEventTarget *target);

   // Wrapper for nsEventQueue that supports chaining.

   class nsChainedEventQueue {

   public:

     nsChainedEventQueue()

       : mNext(nullptr) {

     }

     bool GetEvent(bool mayWait, nsIRunnable **event) {

       return mQueue.GetEvent(mayWait, event);

     }

     bool PutEvent(nsIRunnable *event) {

       return mQueue.PutEvent(event);

     }

     bool HasPendingEvent() {

       return mQueue.HasPendingEvent();

     }

     nsChainedEventQueue *mNext;

     nsRefPtr<nsNestedEventTarget> mEventTarget;

   private:

     nsEventQueue mQueue;

   };

   class nsNestedEventTarget MOZ_FINAL : public nsIEventTarget {

   public:

     NS_DECL_THREADSAFE_ISUPPORTS

     NS_DECL_NSIEVENTTARGET

     nsNestedEventTarget(nsThread *thread, nsChainedEventQueue *queue)

       : mThread(thread), mQueue(queue) {

     }

     nsRefPtr<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;

   // Only accessed on the target thread.

   nsAutoTObserverArray<nsCOMPtr<nsIThreadObserver>, 2> mEventObservers;

   nsChainedEventQueue *mEvents;   // never null

   nsChainedEventQueue  mEventsRoot;

   int32_t   mPriority;

   PRThread *mThread;

   uint32_t  mRunningEvent;  // counter

   uint32_t  mStackSize;

   struct nsThreadShutdownContext *mShutdownContext;

   bool mShutdownRequired;

   // Set to true when events posted to this thread will never run.

   bool mEventsAreDoomed;

   MainThreadFlag mIsMainThread;

 };

 //-----------------------------------------------------------------------------

 class nsThreadSyncDispatch : public nsRunnable {

 public:

   nsThreadSyncDispatch(nsIThread *origin, nsIRunnable *task)

     : mOrigin(origin), mSyncTask(task), mResult(NS_ERROR_NOT_INITIALIZED) {

   }

   bool IsPending() {

     return mSyncTask != nullptr;

   }

   nsresult Result() {

     return mResult;

   }

 private:

   NS_DECL_NSIRUNNABLE

   nsCOMPtr<nsIThread> mOrigin;

   nsCOMPtr<nsIRunnable> mSyncTask;

   nsresult mResult;

 };

 #if defined(XP_UNIX) && !defined(ANDROID) && !defined(DEBUG) && HAVE_UALARM \

   && defined(_GNU_SOURCE)

 # define MOZ_CANARY

 extern int sCanaryOutputFD;

 #endif

 #endif  // nsThread_h__