Add m-esr52 at 52.6.0

1 files changed, 863 insertions, 0 deletions

diff --git a/dom/media/MediaStreamGraphImpl.h b/dom/media/MediaStreamGraphImpl.h
new file mode 100644
index 000000000..c71975493
--- /dev/null
+++ b/dom/media/MediaStreamGraphImpl.h
@@ -0,0 +1,863 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
+/* 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_MEDIASTREAMGRAPHIMPL_H_
+#define MOZILLA_MEDIASTREAMGRAPHIMPL_H_
+
+#include "MediaStreamGraph.h"
+
+#include "nsDataHashtable.h"
+
+#include "nsITimer.h"
+#include "mozilla/Monitor.h"
+#include "mozilla/TimeStamp.h"
+#include "nsIMemoryReporter.h"
+#include "nsIThread.h"
+#include "nsIRunnable.h"
+#include "nsIAsyncShutdown.h"
+#include "Latency.h"
+#include "mozilla/Services.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/WeakPtr.h"
+#include "GraphDriver.h"
+#include "AudioMixer.h"
+
+namespace mozilla {
+
+template <typename T>
+class LinkedList;
+#ifdef MOZ_WEBRTC
+class AudioOutputObserver;
+#endif
+
+/**
+ * A per-stream update message passed from the media graph thread to the
+ * main thread.
+ */
+struct StreamUpdate
+{
+  RefPtr<MediaStream> mStream;
+  StreamTime mNextMainThreadCurrentTime;
+  bool mNextMainThreadFinished;
+};
+
+/**
+ * This represents a message run on the graph thread to modify stream or graph
+ * state.  These are passed from main thread to graph thread through
+ * AppendMessage(), or scheduled on the graph thread with
+ * RunMessageAfterProcessing().  A ControlMessage
+ * always has a weak reference to a particular affected stream.
+ */
+class ControlMessage
+{
+public:
+  explicit ControlMessage(MediaStream* aStream) : mStream(aStream)
+  {
+    MOZ_COUNT_CTOR(ControlMessage);
+  }
+  // All these run on the graph thread
+  virtual ~ControlMessage()
+  {
+    MOZ_COUNT_DTOR(ControlMessage);
+  }
+  // Do the action of this message on the MediaStreamGraph thread. Any actions
+  // affecting graph processing should take effect at mProcessedTime.
+  // All stream data for times < mProcessedTime has already been
+  // computed.
+  virtual void Run() = 0;
+  // RunDuringShutdown() is only relevant to messages generated on the main
+  // thread (for AppendMessage()).
+  // When we're shutting down the application, most messages are ignored but
+  // some cleanup messages should still be processed (on the main thread).
+  // This must not add new control messages to the graph.
+  virtual void RunDuringShutdown() {}
+  MediaStream* GetStream() { return mStream; }
+
+protected:
+  // We do not hold a reference to mStream. The graph will be holding
+  // a reference to the stream until the Destroy message is processed. The
+  // last message referencing a stream is the Destroy message for that stream.
+  MediaStream* mStream;
+};
+
+class MessageBlock
+{
+public:
+  nsTArray<UniquePtr<ControlMessage>> mMessages;
+};
+
+/**
+ * The implementation of a media stream graph. This class is private to this
+ * file. It's not in the anonymous namespace because MediaStream needs to
+ * be able to friend it.
+ *
+ * There can be multiple MediaStreamGraph per process: one per AudioChannel.
+ * Additionaly, each OfflineAudioContext object creates its own MediaStreamGraph
+ * object too.
+ */
+class MediaStreamGraphImpl : public MediaStreamGraph,
+                             public nsIMemoryReporter,
+                             public nsITimerCallback
+{
+public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIMEMORYREPORTER
+  NS_DECL_NSITIMERCALLBACK
+
+  /**
+   * Use aGraphDriverRequested with SYSTEM_THREAD_DRIVER or AUDIO_THREAD_DRIVER
+   * to create a MediaStreamGraph which provides support for real-time audio
+   * and/or video.  Set it to OFFLINE_THREAD_DRIVER in order to create a
+   * non-realtime instance which just churns through its inputs and produces
+   * output.  Those objects currently only support audio, and are used to
+   * implement OfflineAudioContext.  They do not support MediaStream inputs.
+   */
+  explicit MediaStreamGraphImpl(GraphDriverType aGraphDriverRequested,
+                                TrackRate aSampleRate,
+                                dom::AudioChannel aChannel);
+
+  /**
+   * Unregisters memory reporting and deletes this instance. This should be
+   * called instead of calling the destructor directly.
+   */
+  void Destroy();
+
+  // Main thread only.
+  /**
+   * This runs every time we need to sync state from the media graph thread
+   * to the main thread while the main thread is not in the middle
+   * of a script. It runs during a "stable state" (per HTML5) or during
+   * an event posted to the main thread.
+   * The boolean affects which boolean controlling runnable dispatch is cleared
+   */
+  void RunInStableState(bool aSourceIsMSG);
+  /**
+   * Ensure a runnable to run RunInStableState is posted to the appshell to
+   * run at the next stable state (per HTML5).
+   * See EnsureStableStateEventPosted.
+   */
+  void EnsureRunInStableState();
+  /**
+   * Called to apply a StreamUpdate to its stream.
+   */
+  void ApplyStreamUpdate(StreamUpdate* aUpdate);
+  /**
+   * Append a ControlMessage to the message queue. This queue is drained
+   * during RunInStableState; the messages will run on the graph thread.
+   */
+  void AppendMessage(UniquePtr<ControlMessage> aMessage);
+
+  // Shutdown helpers.
+
+  static already_AddRefed<nsIAsyncShutdownClient>
+  GetShutdownBarrier()
+  {
+    nsCOMPtr<nsIAsyncShutdownService> svc = services::GetAsyncShutdown();
+    MOZ_RELEASE_ASSERT(svc);
+
+    nsCOMPtr<nsIAsyncShutdownClient> barrier;
+    nsresult rv = svc->GetProfileBeforeChange(getter_AddRefs(barrier));
+    if (!barrier) {
+      // We are probably in a content process. We need to do cleanup at
+      // XPCOM shutdown in leakchecking builds.
+      rv = svc->GetXpcomWillShutdown(getter_AddRefs(barrier));
+    }
+    MOZ_RELEASE_ASSERT(NS_SUCCEEDED(rv));
+    MOZ_RELEASE_ASSERT(barrier);
+    return barrier.forget();
+  }
+
+  class ShutdownTicket final
+  {
+  public:
+    explicit ShutdownTicket(nsIAsyncShutdownBlocker* aBlocker) : mBlocker(aBlocker) {}
+    NS_INLINE_DECL_REFCOUNTING(ShutdownTicket)
+  private:
+    ~ShutdownTicket()
+    {
+      nsCOMPtr<nsIAsyncShutdownClient> barrier = GetShutdownBarrier();
+      barrier->RemoveBlocker(mBlocker);
+    }
+
+    nsCOMPtr<nsIAsyncShutdownBlocker> mBlocker;
+  };
+
+  /**
+   * Make this MediaStreamGraph enter forced-shutdown state. This state
+   * will be noticed by the media graph thread, which will shut down all streams
+   * and other state controlled by the media graph thread.
+   * This is called during application shutdown.
+   */
+  void ForceShutDown(ShutdownTicket* aShutdownTicket);
+
+  /**
+   * Called before the thread runs.
+   */
+  void Init();
+
+  /**
+   * Respond to CollectReports with sizes collected on the graph thread.
+   */
+  static void
+  FinishCollectReports(nsIHandleReportCallback* aHandleReport,
+                       nsISupports* aData,
+                       const nsTArray<AudioNodeSizes>& aAudioStreamSizes);
+
+  // The following methods run on the graph thread (or possibly the main thread
+  // if mLifecycleState > LIFECYCLE_RUNNING)
+  void CollectSizesForMemoryReport(
+         already_AddRefed<nsIHandleReportCallback> aHandleReport,
+         already_AddRefed<nsISupports> aHandlerData);
+
+  /**
+   * Returns true if this MediaStreamGraph should keep running
+   */
+  bool UpdateMainThreadState();
+
+  /**
+   * Returns true if this MediaStreamGraph should keep running
+   */
+  bool OneIteration(GraphTime aStateEnd);
+
+  /**
+   * Called from the driver, when the graph thread is about to stop, to tell
+   * the main thread to attempt to begin cleanup.  The main thread may either
+   * shutdown or revive the graph depending on whether it receives new
+   * messages.
+   */
+  void SignalMainThreadCleanup();
+
+  bool Running() const
+  {
+    mMonitor.AssertCurrentThreadOwns();
+    return mLifecycleState == LIFECYCLE_RUNNING;
+  }
+
+  /* This is the end of the current iteration, that is, the current time of the
+   * graph. */
+  GraphTime IterationEnd() const;
+
+  /**
+   * Ensure there is an event posted to the main thread to run RunInStableState.
+   * mMonitor must be held.
+   * See EnsureRunInStableState
+   */
+  void EnsureStableStateEventPosted();
+  /**
+   * Generate messages to the main thread to update it for all state changes.
+   * mMonitor must be held.
+   */
+  void PrepareUpdatesToMainThreadState(bool aFinalUpdate);
+  /**
+   * Returns false if there is any stream that has finished but not yet finished
+   * playing out.
+   */
+  bool AllFinishedStreamsNotified();
+  /**
+   * If we are rendering in non-realtime mode, we don't want to send messages to
+   * the main thread at each iteration for performance reasons. We instead
+   * notify the main thread at the same rate
+   */
+  bool ShouldUpdateMainThread();
+  // The following methods are the various stages of RunThread processing.
+  /**
+   * Advance all stream state to mStateComputedTime.
+   */
+  void UpdateCurrentTimeForStreams(GraphTime aPrevCurrentTime);
+  /**
+   * Process chunks for all streams and raise events for properties that have
+   * changed, such as principalId.
+   */
+  void ProcessChunkMetadata(GraphTime aPrevCurrentTime);
+  /**
+   * Process chunks for the given stream and interval, and raise events for
+   * properties that have changed, such as principalId.
+   */
+  template<typename C, typename Chunk>
+  void ProcessChunkMetadataForInterval(MediaStream* aStream,
+                                       TrackID aTrackID,
+                                       C& aSegment,
+                                       StreamTime aStart,
+                                       StreamTime aEnd);
+  /**
+   * Process graph messages in mFrontMessageQueue.
+   */
+  void RunMessagesInQueue();
+  /**
+   * Update stream processing order and recompute stream blocking until
+   * aEndBlockingDecisions.
+   */
+  void UpdateGraph(GraphTime aEndBlockingDecisions);
+
+  void SwapMessageQueues()
+  {
+    MOZ_ASSERT(CurrentDriver()->OnThread());
+    MOZ_ASSERT(mFrontMessageQueue.IsEmpty());
+    mMonitor.AssertCurrentThreadOwns();
+    mFrontMessageQueue.SwapElements(mBackMessageQueue);
+  }
+  /**
+   * Do all the processing and play the audio and video, from
+   * mProcessedTime to mStateComputedTime.
+   */
+  void Process();
+  /**
+   * Extract any state updates pending in aStream, and apply them.
+   */
+  void ExtractPendingInput(SourceMediaStream* aStream,
+                           GraphTime aDesiredUpToTime,
+                           bool* aEnsureNextIteration);
+
+  /**
+   * For use during ProcessedMediaStream::ProcessInput() or
+   * MediaStreamListener callbacks, when graph state cannot be changed.
+   * Schedules |aMessage| to run after processing, at a time when graph state
+   * can be changed.  Graph thread.
+   */
+  void RunMessageAfterProcessing(UniquePtr<ControlMessage> aMessage);
+
+  /**
+   * Called when a suspend/resume/close operation has been completed, on the
+   * graph thread.
+   */
+  void AudioContextOperationCompleted(MediaStream* aStream,
+                                      void* aPromise,
+                                      dom::AudioContextOperation aOperation);
+
+  /**
+   * Apply and AudioContext operation (suspend/resume/closed), on the graph
+   * thread.
+   */
+  void ApplyAudioContextOperationImpl(MediaStream* aDestinationStream,
+                                      const nsTArray<MediaStream*>& aStreams,
+                                      dom::AudioContextOperation aOperation,
+                                      void* aPromise);
+
+  /**
+   * Increment suspend count on aStream and move it to mSuspendedStreams if
+   * necessary.
+   */
+  void IncrementSuspendCount(MediaStream* aStream);
+  /**
+   * Increment suspend count on aStream and move it to mStreams if
+   * necessary.
+   */
+  void DecrementSuspendCount(MediaStream* aStream);
+
+  /*
+   * Move streams from the mStreams to mSuspendedStream if suspending/closing an
+   * AudioContext, or the inverse when resuming an AudioContext.
+   */
+  void SuspendOrResumeStreams(dom::AudioContextOperation aAudioContextOperation,
+                              const nsTArray<MediaStream*>& aStreamSet);
+
+  /**
+   * Determine if we have any audio tracks, or are about to add any audiotracks.
+   * Also checks if we'll need the AEC running (i.e. microphone input tracks)
+   */
+  bool AudioTrackPresent(bool& aNeedsAEC);
+
+  /**
+   * Sort mStreams so that every stream not in a cycle is after any streams
+   * it depends on, and every stream in a cycle is marked as being in a cycle.
+   * Also sets mIsConsumed on every stream.
+   */
+  void UpdateStreamOrder();
+
+  /**
+   * Returns smallest value of t such that t is a multiple of
+   * WEBAUDIO_BLOCK_SIZE and t > aTime.
+   */
+  GraphTime RoundUpToNextAudioBlock(GraphTime aTime);
+  /**
+   * Produce data for all streams >= aStreamIndex for the current time interval.
+   * Advances block by block, each iteration producing data for all streams
+   * for a single block.
+   * This is called whenever we have an AudioNodeStream in the graph.
+   */
+  void ProduceDataForStreamsBlockByBlock(uint32_t aStreamIndex,
+                                         TrackRate aSampleRate);
+  /**
+   * If aStream will underrun between aTime, and aEndBlockingDecisions, returns
+   * the time at which the underrun will start. Otherwise return
+   * aEndBlockingDecisions.
+   */
+  GraphTime WillUnderrun(MediaStream* aStream, GraphTime aEndBlockingDecisions);
+
+  /**
+   * Given a graph time aTime, convert it to a stream time taking into
+   * account the time during which aStream is scheduled to be blocked.
+   */
+  StreamTime GraphTimeToStreamTimeWithBlocking(MediaStream* aStream, GraphTime aTime);
+
+  /**
+   * Call NotifyHaveCurrentData on aStream's listeners.
+   */
+  void NotifyHasCurrentData(MediaStream* aStream);
+  /**
+   * If aStream needs an audio stream but doesn't have one, create it.
+   * If aStream doesn't need an audio stream but has one, destroy it.
+   */
+  void CreateOrDestroyAudioStreams(MediaStream* aStream);
+  /**
+   * Queue audio (mix of stream audio and silence for blocked intervals)
+   * to the audio output stream. Returns the number of frames played.
+   */
+  StreamTime PlayAudio(MediaStream* aStream);
+  /**
+   * No more data will be forthcoming for aStream. The stream will end
+   * at the current buffer end point. The StreamTracks's tracks must be
+   * explicitly set to finished by the caller.
+   */
+  void OpenAudioInputImpl(int aID,
+                          AudioDataListener *aListener);
+  virtual nsresult OpenAudioInput(int aID,
+                                  AudioDataListener *aListener) override;
+  void CloseAudioInputImpl(AudioDataListener *aListener);
+  virtual void CloseAudioInput(AudioDataListener *aListener) override;
+
+  void FinishStream(MediaStream* aStream);
+  /**
+   * Compute how much stream data we would like to buffer for aStream.
+   */
+  StreamTime GetDesiredBufferEnd(MediaStream* aStream);
+  /**
+   * Returns true when there are no active streams.
+   */
+  bool IsEmpty() const
+  {
+    return mStreams.IsEmpty() && mSuspendedStreams.IsEmpty() && mPortCount == 0;
+  }
+
+  /**
+   * Add aStream to the graph and initializes its graph-specific state.
+   */
+  void AddStreamGraphThread(MediaStream* aStream);
+  /**
+   * Remove aStream from the graph. Ensures that pending messages about the
+   * stream back to the main thread are flushed.
+   */
+  void RemoveStreamGraphThread(MediaStream* aStream);
+  /**
+   * Remove aPort from the graph and release it.
+   */
+  void DestroyPort(MediaInputPort* aPort);
+  /**
+   * Mark the media stream order as dirty.
+   */
+  void SetStreamOrderDirty()
+  {
+    mStreamOrderDirty = true;
+  }
+
+  // Always stereo for now.
+  uint32_t AudioChannelCount() const { return 2; }
+
+  double MediaTimeToSeconds(GraphTime aTime) const
+  {
+    NS_ASSERTION(aTime > -STREAM_TIME_MAX && aTime <= STREAM_TIME_MAX,
+                 "Bad time");
+    return static_cast<double>(aTime)/GraphRate();
+  }
+
+  GraphTime SecondsToMediaTime(double aS) const
+  {
+    NS_ASSERTION(0 <= aS && aS <= TRACK_TICKS_MAX/TRACK_RATE_MAX,
+                 "Bad seconds");
+    return GraphRate() * aS;
+  }
+
+  GraphTime MillisecondsToMediaTime(int32_t aMS) const
+  {
+    return RateConvertTicksRoundDown(GraphRate(), 1000, aMS);
+  }
+
+  /**
+   * Signal to the graph that the thread has paused indefinitly,
+   * or resumed.
+   */
+  void PausedIndefinitly();
+  void ResumedFromPaused();
+
+  /**
+   * Not safe to call off the MediaStreamGraph thread unless monitor is held!
+   */
+  GraphDriver* CurrentDriver() const
+  {
+    AssertOnGraphThreadOrNotRunning();
+    return mDriver;
+  }
+
+  bool RemoveMixerCallback(MixerCallbackReceiver* aReceiver)
+  {
+    return mMixer.RemoveCallback(aReceiver);
+  }
+
+  /**
+   * Effectively set the new driver, while we are switching.
+   * It is only safe to call this at the very end of an iteration, when there
+   * has been a SwitchAtNextIteration call during the iteration. The driver
+   * should return and pass the control to the new driver shortly after.
+   * We can also switch from Revive() (on MainThread), in which case the
+   * monitor is held
+   */
+  void SetCurrentDriver(GraphDriver* aDriver)
+  {
+    AssertOnGraphThreadOrNotRunning();
+    mDriver = aDriver;
+  }
+
+  Monitor& GetMonitor()
+  {
+    return mMonitor;
+  }
+
+  void EnsureNextIteration()
+  {
+    mNeedAnotherIteration = true; // atomic
+    // Note: GraphDriver must ensure that there's no race on setting
+    // mNeedAnotherIteration and mGraphDriverAsleep -- see WaitForNextIteration()
+    if (mGraphDriverAsleep) { // atomic
+      MonitorAutoLock mon(mMonitor);
+      CurrentDriver()->WakeUp(); // Might not be the same driver; might have woken already
+    }
+  }
+
+  void EnsureNextIterationLocked()
+  {
+    mNeedAnotherIteration = true; // atomic
+    if (mGraphDriverAsleep) { // atomic
+      CurrentDriver()->WakeUp(); // Might not be the same driver; might have woken already
+    }
+  }
+
+  // Capture Stream API. This allows to get a mixed-down output for a window.
+  void RegisterCaptureStreamForWindow(uint64_t aWindowId,
+                                      ProcessedMediaStream* aCaptureStream);
+  void UnregisterCaptureStreamForWindow(uint64_t aWindowId);
+  already_AddRefed<MediaInputPort>
+  ConnectToCaptureStream(uint64_t aWindowId, MediaStream* aMediaStream);
+
+  class StreamSet {
+  public:
+    class iterator {
+    public:
+      explicit iterator(MediaStreamGraphImpl& aGraph)
+        : mGraph(&aGraph), mArrayNum(-1), mArrayIndex(0)
+      {
+        ++(*this);
+      }
+      iterator() : mGraph(nullptr), mArrayNum(2), mArrayIndex(0) {}
+      MediaStream* operator*()
+      {
+        return Array()->ElementAt(mArrayIndex);
+      }
+      iterator operator++()
+      {
+        ++mArrayIndex;
+        while (mArrayNum < 2 &&
+          (mArrayNum < 0 || mArrayIndex >= Array()->Length())) {
+          ++mArrayNum;
+          mArrayIndex = 0;
+        }
+        return *this;
+      }
+      bool operator==(const iterator& aOther) const
+      {
+        return mArrayNum == aOther.mArrayNum && mArrayIndex == aOther.mArrayIndex;
+      }
+      bool operator!=(const iterator& aOther) const
+      {
+        return !(*this == aOther);
+      }
+    private:
+      nsTArray<MediaStream*>* Array()
+      {
+        return mArrayNum == 0 ? &mGraph->mStreams : &mGraph->mSuspendedStreams;
+      }
+      MediaStreamGraphImpl* mGraph;
+      int mArrayNum;
+      uint32_t mArrayIndex;
+    };
+
+    explicit StreamSet(MediaStreamGraphImpl& aGraph) : mGraph(aGraph) {}
+    iterator begin() { return iterator(mGraph); }
+    iterator end() { return iterator(); }
+  private:
+    MediaStreamGraphImpl& mGraph;
+  };
+  StreamSet AllStreams() { return StreamSet(*this); }
+
+  // Data members
+  //
+  /**
+   * Graphs own owning references to their driver, until shutdown. When a driver
+   * switch occur, previous driver is either deleted, or it's ownership is
+   * passed to a event that will take care of the asynchronous cleanup, as
+   * audio stream can take some time to shut down.
+   */
+  RefPtr<GraphDriver> mDriver;
+
+  // The following state is managed on the graph thread only, unless
+  // mLifecycleState > LIFECYCLE_RUNNING in which case the graph thread
+  // is not running and this state can be used from the main thread.
+
+  /**
+   * The graph keeps a reference to each stream.
+   * References are maintained manually to simplify reordering without
+   * unnecessary thread-safe refcount changes.
+   */
+  nsTArray<MediaStream*> mStreams;
+  /**
+   * This stores MediaStreams that are part of suspended AudioContexts.
+   * mStreams and mSuspendStream are disjoint sets: a stream is either suspended
+   * or not suspended. Suspended streams are not ordered in UpdateStreamOrder,
+   * and are therefore not doing any processing.
+   */
+  nsTArray<MediaStream*> mSuspendedStreams;
+  /**
+   * Suspended AudioContext IDs
+   */
+  nsTHashtable<nsUint64HashKey> mSuspendedContexts;
+  /**
+   * Streams from mFirstCycleBreaker to the end of mStreams produce output
+   * before they receive input.  They correspond to DelayNodes that are in
+   * cycles.
+   */
+  uint32_t mFirstCycleBreaker;
+  /**
+   * Blocking decisions have been computed up to this time.
+   * Between each iteration, this is the same as mProcessedTime.
+   */
+  GraphTime mStateComputedTime = 0;
+  /**
+   * All stream contents have been computed up to this time.
+   * The next batch of updates from the main thread will be processed
+   * at this time.  This is behind mStateComputedTime during processing.
+   */
+  GraphTime mProcessedTime = 0;
+  /**
+   * Date of the last time we updated the main thread with the graph state.
+   */
+  TimeStamp mLastMainThreadUpdate;
+  /**
+   * Number of active MediaInputPorts
+   */
+  int32_t mPortCount;
+
+  /**
+   * Devices to use for cubeb input & output, or NULL for no input (void*),
+   * and boolean to control if we want input/output
+   */
+  bool mInputWanted;
+  int mInputDeviceID;
+  bool mOutputWanted;
+  int mOutputDeviceID;
+  // Maps AudioDataListeners to a usecount of streams using the listener
+  // so we can know when it's no longer in use.
+  nsDataHashtable<nsPtrHashKey<AudioDataListener>, uint32_t> mInputDeviceUsers;
+
+  // True if the graph needs another iteration after the current iteration.
+  Atomic<bool> mNeedAnotherIteration;
+  // GraphDriver may need a WakeUp() if something changes
+  Atomic<bool> mGraphDriverAsleep;
+
+  // mMonitor guards the data below.
+  // MediaStreamGraph normally does its work without holding mMonitor, so it is
+  // not safe to just grab mMonitor from some thread and start monkeying with
+  // the graph. Instead, communicate with the graph thread using provided
+  // mechanisms such as the ControlMessage queue.
+  Monitor mMonitor;
+
+  // Data guarded by mMonitor (must always be accessed with mMonitor held,
+  // regardless of the value of mLifecycleState).
+
+  /**
+   * State to copy to main thread
+   */
+  nsTArray<StreamUpdate> mStreamUpdates;
+  /**
+   * Runnables to run after the next update to main thread state.
+   */
+  nsTArray<nsCOMPtr<nsIRunnable> > mUpdateRunnables;
+  /**
+   * A list of batches of messages to process. Each batch is processed
+   * as an atomic unit.
+   */
+  /*
+   * Message queue processed by the MSG thread during an iteration.
+   * Accessed on graph thread only.
+   */
+  nsTArray<MessageBlock> mFrontMessageQueue;
+  /*
+   * Message queue in which the main thread appends messages.
+   * Access guarded by mMonitor.
+   */
+  nsTArray<MessageBlock> mBackMessageQueue;
+
+  /* True if there will messages to process if we swap the message queues. */
+  bool MessagesQueued() const
+  {
+    mMonitor.AssertCurrentThreadOwns();
+    return !mBackMessageQueue.IsEmpty();
+  }
+  /**
+   * This enum specifies where this graph is in its lifecycle. This is used
+   * to control shutdown.
+   * Shutdown is tricky because it can happen in two different ways:
+   * 1) Shutdown due to inactivity. RunThread() detects that it has no
+   * pending messages and no streams, and exits. The next RunInStableState()
+   * checks if there are new pending messages from the main thread (true only
+   * if new stream creation raced with shutdown); if there are, it revives
+   * RunThread(), otherwise it commits to shutting down the graph. New stream
+   * creation after this point will create a new graph. An async event is
+   * dispatched to Shutdown() the graph's threads and then delete the graph
+   * object.
+   * 2) Forced shutdown at application shutdown, or completion of a
+   * non-realtime graph. A flag is set, RunThread() detects the flag and
+   * exits, the next RunInStableState() detects the flag, and dispatches the
+   * async event to Shutdown() the graph's threads. However the graph object
+   * is not deleted. New messages for the graph are processed synchronously on
+   * the main thread if necessary. When the last stream is destroyed, the
+   * graph object is deleted.
+   *
+   * This should be kept in sync with the LifecycleState_str array in
+   * MediaStreamGraph.cpp
+   */
+  enum LifecycleState
+  {
+    // The graph thread hasn't started yet.
+    LIFECYCLE_THREAD_NOT_STARTED,
+    // RunThread() is running normally.
+    LIFECYCLE_RUNNING,
+    // In the following states, the graph thread is not running so
+    // all "graph thread only" state in this class can be used safely
+    // on the main thread.
+    // RunThread() has exited and we're waiting for the next
+    // RunInStableState(), at which point we can clean up the main-thread
+    // side of the graph.
+    LIFECYCLE_WAITING_FOR_MAIN_THREAD_CLEANUP,
+    // RunInStableState() posted a ShutdownRunnable, and we're waiting for it
+    // to shut down the graph thread(s).
+    LIFECYCLE_WAITING_FOR_THREAD_SHUTDOWN,
+    // Graph threads have shut down but we're waiting for remaining streams
+    // to be destroyed. Only happens during application shutdown and on
+    // completed non-realtime graphs, since normally we'd only shut down a
+    // realtime graph when it has no streams.
+    LIFECYCLE_WAITING_FOR_STREAM_DESTRUCTION
+  };
+  /**
+   * Modified only in mMonitor.  Transitions to
+   * LIFECYCLE_WAITING_FOR_MAIN_THREAD_CLEANUP occur on the graph thread at
+   * the end of an iteration.  All other transitions occur on the main thread.
+   */
+  LifecycleState mLifecycleState;
+  /**
+   * The graph should stop processing at or after this time.
+   */
+  GraphTime mEndTime;
+
+  /**
+   * True when we need to do a forced shutdown during application shutdown.
+   */
+  bool mForceShutDown;
+
+  /**
+   * Drop this reference during shutdown to unblock shutdown.
+   **/
+  RefPtr<ShutdownTicket> mForceShutdownTicket;
+
+  /**
+   * True when we have posted an event to the main thread to run
+   * RunInStableState() and the event hasn't run yet.
+   */
+  bool mPostedRunInStableStateEvent;
+
+  // Main thread only
+
+  /**
+   * Messages posted by the current event loop task. These are forwarded to
+   * the media graph thread during RunInStableState. We can't forward them
+   * immediately because we want all messages between stable states to be
+   * processed as an atomic batch.
+   */
+  nsTArray<UniquePtr<ControlMessage>> mCurrentTaskMessageQueue;
+  /**
+   * True when RunInStableState has determined that mLifecycleState is >
+   * LIFECYCLE_RUNNING. Since only the main thread can reset mLifecycleState to
+   * LIFECYCLE_RUNNING, this can be relied on to not change unexpectedly.
+   */
+  bool mDetectedNotRunning;
+  /**
+   * True when a stable state runner has been posted to the appshell to run
+   * RunInStableState at the next stable state.
+   */
+  bool mPostedRunInStableState;
+  /**
+   * True when processing real-time audio/video.  False when processing non-realtime
+   * audio.
+   */
+  bool mRealtime;
+  /**
+   * True when a non-realtime MediaStreamGraph has started to process input.  This
+   * value is only accessed on the main thread.
+   */
+  bool mNonRealtimeProcessing;
+  /**
+   * True when a change has happened which requires us to recompute the stream
+   * blocking order.
+   */
+  bool mStreamOrderDirty;
+  /**
+   * Hold a ref to the Latency logger
+   */
+  RefPtr<AsyncLatencyLogger> mLatencyLog;
+  AudioMixer mMixer;
+#ifdef MOZ_WEBRTC
+  RefPtr<AudioOutputObserver> mFarendObserverRef;
+#endif
+
+  dom::AudioChannel AudioChannel() const { return mAudioChannel; }
+
+  // used to limit graph shutdown time
+  nsCOMPtr<nsITimer> mShutdownTimer;
+
+private:
+  virtual ~MediaStreamGraphImpl();
+
+  MOZ_DEFINE_MALLOC_SIZE_OF(MallocSizeOf)
+
+  /**
+   * This class uses manual memory management, and all pointers to it are raw
+   * pointers. However, in order for it to implement nsIMemoryReporter, it needs
+   * to implement nsISupports and so be ref-counted. So it maintains a single
+   * nsRefPtr to itself, giving it a ref-count of 1 during its entire lifetime,
+   * and Destroy() nulls this self-reference in order to trigger self-deletion.
+   */
+  RefPtr<MediaStreamGraphImpl> mSelfRef;
+
+  struct WindowAndStream
+  {
+    uint64_t mWindowId;
+    RefPtr<ProcessedMediaStream> mCaptureStreamSink;
+  };
+  /**
+   * Stream for window audio capture.
+   */
+  nsTArray<WindowAndStream> mWindowCaptureStreams;
+
+#ifdef DEBUG
+  /**
+   * Used to assert when AppendMessage() runs ControlMessages synchronously.
+   */
+  bool mCanRunMessagesSynchronously;
+#endif
+
+  dom::AudioChannel mAudioChannel;
+};
+
+} // namespace mozilla
+
+#endif /* MEDIASTREAMGRAPHIMPL_H_ */