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+/* -*- 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_MEDIATRACKGRAPHIMPL_H_
+#define MOZILLA_MEDIATRACKGRAPHIMPL_H_
+
+#include "MediaTrackGraph.h"
+
+#include "AudioMixer.h"
+#include "GraphDriver.h"
+#include "DeviceInputTrack.h"
+#include "mozilla/Atomics.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/Monitor.h"
+#include "mozilla/TimeStamp.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/WeakPtr.h"
+#include "nsClassHashtable.h"
+#include "nsIMemoryReporter.h"
+#include "nsINamed.h"
+#include "nsIRunnable.h"
+#include "nsIThreadInternal.h"
+#include "nsITimer.h"
+#include "AsyncLogger.h"
+
+namespace mozilla {
+
+namespace media {
+class ShutdownBlocker;
+}
+
+class AudioContextOperationControlMessage;
+template <typename T>
+class LinkedList;
+class GraphRunner;
+
+class DeviceInputTrackManager {
+ public:
+ DeviceInputTrackManager() = default;
+
+ // Returns the current NativeInputTrack.
+ NativeInputTrack* GetNativeInputTrack();
+ // Returns the DeviceInputTrack paired with the device of aID if it exists.
+ // Otherwise, returns nullptr.
+ DeviceInputTrack* GetDeviceInputTrack(CubebUtils::AudioDeviceID aID);
+ // Returns the first added NonNativeInputTrack if any. Otherwise, returns
+ // nullptr.
+ NonNativeInputTrack* GetFirstNonNativeInputTrack();
+ // Adds DeviceInputTrack to the managing list.
+ void Add(DeviceInputTrack* aTrack);
+ // Removes DeviceInputTrack from the managing list.
+ void Remove(DeviceInputTrack* aTrack);
+
+ private:
+ RefPtr<NativeInputTrack> mNativeInputTrack;
+ nsTArray<RefPtr<NonNativeInputTrack>> mNonNativeInputTracks;
+};
+
+/**
+ * A per-track update message passed from the media graph thread to the
+ * main thread.
+ */
+struct TrackUpdate {
+ RefPtr<MediaTrack> mTrack;
+ TrackTime mNextMainThreadCurrentTime;
+ bool mNextMainThreadEnded;
+};
+
+/**
+ * This represents a message run on the graph thread to modify track or graph
+ * state. These are passed from main thread to graph thread through
+ * AppendMessage(). A ControlMessage often has a weak reference to a
+ * particular affected track.
+ */
+class ControlMessage : public MediaTrack::ControlMessageInterface {
+ public:
+ explicit ControlMessage(MediaTrack* aTrack) : mTrack(aTrack) {
+ MOZ_ASSERT(NS_IsMainThread());
+ MOZ_RELEASE_ASSERT(!aTrack || !aTrack->IsDestroyed());
+ }
+
+ MediaTrack* GetTrack() { return mTrack; }
+
+ protected:
+ // We do not hold a reference to mTrack. The graph will be holding a reference
+ // to the track until the Destroy message is processed. The last message
+ // referencing a track is the Destroy message for that track.
+ MediaTrack* const mTrack;
+};
+
+class MessageBlock {
+ public:
+ nsTArray<UniquePtr<MediaTrack::ControlMessageInterface>> mMessages;
+};
+
+/**
+ * The implementation of a media track graph. This class is private to this
+ * file. It's not in the anonymous namespace because MediaTrack needs to
+ * be able to friend it.
+ *
+ * There can be multiple MediaTrackGraph per process: one per document.
+ * Additionaly, each OfflineAudioContext object creates its own MediaTrackGraph
+ * object too.
+ */
+class MediaTrackGraphImpl : public MediaTrackGraph,
+ public GraphInterface,
+ public nsIMemoryReporter,
+ public nsIObserver,
+ public nsIThreadObserver,
+ public nsITimerCallback,
+ public nsINamed {
+ public:
+ using ControlMessageInterface = MediaTrack::ControlMessageInterface;
+
+ NS_DECL_THREADSAFE_ISUPPORTS
+ NS_DECL_NSIMEMORYREPORTER
+ NS_DECL_NSIOBSERVER
+ NS_DECL_NSITHREADOBSERVER
+ NS_DECL_NSITIMERCALLBACK
+ NS_DECL_NSINAMED
+
+ /**
+ * Use aGraphDriverRequested with SYSTEM_THREAD_DRIVER or AUDIO_THREAD_DRIVER
+ * to create a MediaTrackGraph 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 MediaTrack inputs.
+ */
+ explicit MediaTrackGraphImpl(uint64_t aWindowID, TrackRate aSampleRate,
+ CubebUtils::AudioDeviceID aOutputDeviceID,
+ nsISerialEventTarget* aMainThread);
+
+ static MediaTrackGraphImpl* GetInstance(
+ GraphDriverType aGraphDriverRequested, uint64_t aWindowID,
+ TrackRate aSampleRate, CubebUtils::AudioDeviceID aPrimaryOutputDeviceID,
+ nsISerialEventTarget* aMainThread);
+ static MediaTrackGraphImpl* GetInstanceIfExists(
+ uint64_t aWindowID, TrackRate aSampleRate,
+ CubebUtils::AudioDeviceID aPrimaryOutputDeviceID);
+ static MediaTrackGraph* CreateNonRealtimeInstance(TrackRate aSampleRate);
+ // For GraphHashSet:
+ struct Lookup;
+ operator Lookup() const;
+
+ // Intended only for assertions, either on graph thread or not running (in
+ // which case we must be on the main thread).
+ bool OnGraphThreadOrNotRunning() const override;
+ bool OnGraphThread() const override;
+
+ bool Destroyed() const override;
+
+#ifdef DEBUG
+ /**
+ * True if we're on aDriver's thread, or if we're on mGraphRunner's thread
+ * and mGraphRunner is currently run by aDriver.
+ */
+ bool InDriverIteration(const GraphDriver* aDriver) const override;
+#endif
+
+ /**
+ * 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 aSourceIsMTG);
+ /**
+ * 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 TrackUpdate to its track.
+ */
+ void ApplyTrackUpdate(TrackUpdate* aUpdate) MOZ_REQUIRES(mMonitor);
+ /**
+ * Append a control message to the message queue. This queue is drained
+ * during RunInStableState; the messages will run on the graph thread.
+ */
+ virtual void AppendMessage(UniquePtr<ControlMessageInterface> aMessage);
+ /**
+ * Append to the message queue a control message to execute a given lambda
+ * function with no parameters. The lambda will be executed on the graph
+ * thread. The lambda will not be executed if the graph has been forced to
+ * shut down.
+ **/
+ template <typename Function>
+ void QueueControlMessageWithNoShutdown(Function&& aFunction) {
+ AppendMessage(WrapUnique(new MediaTrack::ControlMessageWithNoShutdown(
+ std::forward<Function>(aFunction))));
+ }
+ /**
+ * Append to the message queue a control message to execute a given lambda
+ * function with a single IsInShutdown parameter. A No argument indicates
+ * execution on the thread of a graph that is still running. A Yes argument
+ * indicates execution on the main thread when the graph has been forced to
+ * shut down.
+ **/
+ template <typename Function>
+ void QueueControlOrShutdownMessage(Function&& aFunction) {
+ AppendMessage(WrapUnique(new MediaTrack::ControlOrShutdownMessage(
+ std::forward<Function>(aFunction))));
+ }
+ /* Add or remove an audio output for this track. At most one output may be
+ * registered per key. aPreferredSampleRate is the rate preferred by the
+ * output device; it may be zero to indicate the preferred rate for the
+ * default device; it is unused when aDeviceID is the graph's primary output.
+ */
+ void RegisterAudioOutput(MediaTrack* aTrack, void* aKey,
+ CubebUtils::AudioDeviceID aDeviceID,
+ TrackRate aPreferredSampleRate);
+ void UnregisterAudioOutput(MediaTrack* aTrack, void* aKey);
+
+ void SetAudioOutputVolume(MediaTrack* aTrack, void* aKey, float aVolume);
+ /* Manage the creation and destruction of CrossGraphReceivers.
+ * aPreferredSampleRate is the rate preferred by the output device. */
+ void IncrementOutputDeviceRefCnt(CubebUtils::AudioDeviceID aDeviceID,
+ TrackRate aPreferredSampleRate);
+ void DecrementOutputDeviceRefCnt(CubebUtils::AudioDeviceID aDeviceID);
+ /* Send a control message to update mOutputDevices for main thread changes to
+ * mAudioOutputParams. */
+ void UpdateAudioOutput(MediaTrack* aTrack,
+ CubebUtils::AudioDeviceID aDeviceID);
+ /**
+ * Dispatches a runnable from any thread to the correct main thread for this
+ * MediaTrackGraph.
+ */
+ void Dispatch(already_AddRefed<nsIRunnable>&& aRunnable);
+
+ /**
+ * Make this MediaTrackGraph enter forced-shutdown state. This state
+ * will be noticed by the media graph thread, which will shut down all tracks
+ * and other state controlled by the media graph thread.
+ * This is called during application shutdown, and on document unload if an
+ * AudioContext is using the graph.
+ */
+ void ForceShutDown();
+
+ /**
+ * Sets mShutdownBlocker and makes it block shutdown.
+ * Main thread only. Not idempotent. Returns true if a blocker was added,
+ * false if this failed.
+ */
+ bool AddShutdownBlocker();
+
+ /**
+ * Removes mShutdownBlocker and unblocks shutdown.
+ * Main thread only. Idempotent.
+ */
+ void RemoveShutdownBlocker();
+
+ /**
+ * Called before the thread runs.
+ */
+ void Init(GraphDriverType aDriverRequested, GraphRunType aRunTypeRequested,
+ uint32_t aChannelCount);
+
+ /**
+ * Respond to CollectReports with sizes collected on the graph thread.
+ */
+ static void FinishCollectReports(
+ nsIHandleReportCallback* aHandleReport, nsISupports* aData,
+ const nsTArray<AudioNodeSizes>& aAudioTrackSizes);
+
+ // 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 MediaTrackGraph should keep running
+ */
+ bool UpdateMainThreadState();
+
+ /**
+ * Proxy method called by GraphDriver to iterate the graph.
+ * If this graph was created with GraphRunType SINGLE_THREAD, mGraphRunner
+ * will take care of calling OneIterationImpl from its thread. Otherwise,
+ * OneIterationImpl is called directly. Mixed audio output from the graph is
+ * passed into aMixerReceiver, if it is non-null.
+ */
+ IterationResult OneIteration(GraphTime aStateTime, GraphTime aIterationEnd,
+ MixerCallbackReceiver* aMixerReceiver) override;
+
+ /**
+ * Returns true if this MediaTrackGraph should keep running
+ */
+ IterationResult OneIterationImpl(GraphTime aStateTime,
+ GraphTime aIterationEnd,
+ MixerCallbackReceiver* aMixerReceiver);
+
+ /**
+ * 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();
+
+ /* 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() MOZ_REQUIRES(mMonitor);
+ /**
+ * Generate messages to the main thread to update it for all state changes.
+ * mMonitor must be held.
+ */
+ void PrepareUpdatesToMainThreadState(bool aFinalUpdate)
+ MOZ_REQUIRES(mMonitor);
+ /**
+ * 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 track state to mStateComputedTime.
+ */
+ void UpdateCurrentTimeForTracks(GraphTime aPrevCurrentTime);
+ /**
+ * Process chunks for all tracks and raise events for properties that have
+ * changed, such as principalId.
+ */
+ void ProcessChunkMetadata(GraphTime aPrevCurrentTime);
+ /**
+ * Process chunks for the given track and interval, and raise events for
+ * properties that have changed, such as principalHandle.
+ */
+ template <typename C, typename Chunk>
+ void ProcessChunkMetadataForInterval(MediaTrack* aTrack, C& aSegment,
+ TrackTime aStart, TrackTime aEnd);
+ /**
+ * Process graph messages in mFrontMessageQueue.
+ */
+ void RunMessagesInQueue();
+ /**
+ * Update track processing order and recompute track blocking until
+ * aEndBlockingDecisions.
+ */
+ void UpdateGraph(GraphTime aEndBlockingDecisions);
+
+ void SwapMessageQueues() MOZ_REQUIRES(mMonitor) {
+ MOZ_ASSERT(OnGraphThreadOrNotRunning());
+ mMonitor.AssertCurrentThreadOwns();
+ MOZ_ASSERT(mFrontMessageQueue.IsEmpty());
+ mFrontMessageQueue.SwapElements(mBackMessageQueue);
+ if (!mFrontMessageQueue.IsEmpty()) {
+ EnsureNextIteration();
+ }
+ }
+ /**
+ * Do all the processing and play the audio and video, from
+ * mProcessedTime to mStateComputedTime.
+ */
+ void Process(MixerCallbackReceiver* aMixerReceiver);
+
+ /**
+ * For use during ProcessedMediaTrack::ProcessInput() or
+ * MediaTrackListener 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<ControlMessageInterface> aMessage);
+
+ /* From the main thread, ask the MTG to resolve the returned promise when
+ * the device specified has started.
+ * A null aDeviceID indicates the default audio output device.
+ * The promise is rejected with NS_ERROR_INVALID_ARG if aSink does not
+ * correspond to any output devices used by the graph, or
+ * NS_ERROR_NOT_AVAILABLE if outputs to the device are removed or
+ * NS_ERROR_ILLEGAL_DURING_SHUTDOWN if the graph is force shut down
+ * before the promise could be resolved.
+ */
+ using GraphStartedPromise = GenericPromise;
+ RefPtr<GraphStartedPromise> NotifyWhenDeviceStarted(
+ CubebUtils::AudioDeviceID aDeviceID) override;
+
+ /**
+ * Resolve the GraphStartedPromise when the driver has started processing on
+ * the audio thread after the device has started.
+ * (Audio is initially processed in the FallbackDriver's thread while the
+ * device is starting up.)
+ */
+ void NotifyWhenPrimaryDeviceStarted(
+ MozPromiseHolder<GraphStartedPromise>&& aHolder);
+
+ /**
+ * Apply an AudioContext operation (suspend/resume/close), on the graph
+ * thread.
+ */
+ void ApplyAudioContextOperationImpl(
+ AudioContextOperationControlMessage* aMessage);
+
+ /**
+ * Determine if we have any audio tracks, or are about to add any audiotracks.
+ */
+ bool AudioTrackPresent();
+
+ /**
+ * Schedules a replacement GraphDriver in mNextDriver, if necessary.
+ */
+ void CheckDriver();
+
+ /**
+ * Sort mTracks so that every track not in a cycle is after any tracks
+ * it depends on, and every track in a cycle is marked as being in a cycle.
+ */
+ void UpdateTrackOrder();
+
+ /**
+ * Returns smallest value of t such that t is a multiple of
+ * WEBAUDIO_BLOCK_SIZE and t >= aTime.
+ */
+ static GraphTime RoundUpToEndOfAudioBlock(GraphTime aTime);
+ /**
+ * Returns smallest value of t such that t is a multiple of
+ * WEBAUDIO_BLOCK_SIZE and t > aTime.
+ */
+ static GraphTime RoundUpToNextAudioBlock(GraphTime aTime);
+ /**
+ * Produce data for all tracks >= aTrackIndex for the current time interval.
+ * Advances block by block, each iteration producing data for all tracks
+ * for a single block.
+ * This is called whenever we have an AudioNodeTrack in the graph.
+ */
+ void ProduceDataForTracksBlockByBlock(uint32_t aTrackIndex,
+ TrackRate aSampleRate);
+ /**
+ * If aTrack will underrun between aTime, and aEndBlockingDecisions, returns
+ * the time at which the underrun will start. Otherwise return
+ * aEndBlockingDecisions.
+ */
+ GraphTime WillUnderrun(MediaTrack* aTrack, GraphTime aEndBlockingDecisions);
+
+ /**
+ * Given a graph time aTime, convert it to a track time taking into
+ * account the time during which aTrack is scheduled to be blocked.
+ */
+ TrackTime GraphTimeToTrackTimeWithBlocking(const MediaTrack* aTrack,
+ GraphTime aTime) const;
+
+ private:
+ /**
+ * Set mOutputDeviceForAEC to indicate the audio output to be passed as the
+ * reverse stream for audio echo cancellation. Graph thread.
+ */
+ void SelectOutputDeviceForAEC();
+ /**
+ * Queue audio (mix of track audio and silence for blocked intervals)
+ * to the audio output track. Returns the number of frames played.
+ */
+ struct TrackAndVolume;
+ TrackTime PlayAudio(const TrackAndVolume& aOutput, GraphTime aPlayedTime,
+ uint32_t aOutputChannelCount);
+
+ public:
+ /* Runs off a message on the graph thread when something requests audio from
+ * an input audio device of ID aID, and delivers the input audio frames to
+ * aListener. */
+ void OpenAudioInputImpl(DeviceInputTrack* aTrack);
+ /* Called on the main thread when something requests audio from an input
+ * audio device aID. */
+ virtual void OpenAudioInput(DeviceInputTrack* aTrack) override;
+
+ /* Runs off a message on the graph when input audio from aID is not needed
+ * anymore, for a particular track. It can be that other tracks still need
+ * audio from this audio input device. */
+ void CloseAudioInputImpl(DeviceInputTrack* aTrack);
+ /* Called on the main thread when input audio from aID is not needed
+ * anymore, for a particular track. It can be that other tracks still need
+ * audio from this audio input device. */
+ virtual void CloseAudioInput(DeviceInputTrack* aTrack) override;
+
+ void UnregisterAllAudioOutputs(MediaTrack* aTrack);
+
+ /* Called on the graph thread when the input device settings should be
+ * reevaluated, for example, if the channel count of the input track should
+ * be changed. */
+ void ReevaluateInputDevice(CubebUtils::AudioDeviceID aID);
+
+ /* Called on the graph thread when there is new output data for listeners.
+ * This is the mixed audio output of this MediaTrackGraph. */
+ void NotifyOutputData(const AudioChunk& aChunk);
+ /* Called on the graph thread after an AudioCallbackDriver with an input
+ * stream has stopped. */
+ void NotifyInputStopped() override;
+ /* Called on the graph thread when there is new input data for listeners. This
+ * is the raw audio input for this MediaTrackGraph. */
+ void NotifyInputData(const AudioDataValue* aBuffer, size_t aFrames,
+ TrackRate aRate, uint32_t aChannels,
+ uint32_t aAlreadyBuffered) override;
+ /* Called every time there are changes to input/output audio devices like
+ * plug/unplug etc. This can be called on any thread, and posts a message to
+ * the main thread so that it can post a message to the graph thread. */
+ void DeviceChanged() override;
+ /* Called every time there are changes to input/output audio devices. This is
+ * called on the graph thread. */
+ void DeviceChangedImpl();
+
+ /**
+ * Compute how much track data we would like to buffer for aTrack.
+ */
+ TrackTime GetDesiredBufferEnd(MediaTrack* aTrack);
+ /**
+ * Returns true when there are no active tracks.
+ */
+ bool IsEmpty() const {
+ MOZ_ASSERT(
+ OnGraphThreadOrNotRunning() ||
+ (NS_IsMainThread() &&
+ LifecycleStateRef() >= LIFECYCLE_WAITING_FOR_MAIN_THREAD_CLEANUP));
+ return mTracks.IsEmpty() && mSuspendedTracks.IsEmpty() && mPortCount == 0;
+ }
+
+ /**
+ * Add aTrack to the graph and initializes its graph-specific state.
+ */
+ void AddTrackGraphThread(MediaTrack* aTrack);
+ /**
+ * Remove aTrack from the graph. Ensures that pending messages about the
+ * track back to the main thread are flushed.
+ */
+ void RemoveTrackGraphThread(MediaTrack* aTrack);
+ /**
+ * Remove a track from the graph. Main thread.
+ */
+ void RemoveTrack(MediaTrack* aTrack);
+ /**
+ * Remove aPort from the graph and release it.
+ */
+ void DestroyPort(MediaInputPort* aPort);
+ /**
+ * Mark the media track order as dirty.
+ */
+ void SetTrackOrderDirty() {
+ MOZ_ASSERT(OnGraphThreadOrNotRunning());
+ mTrackOrderDirty = true;
+ }
+
+ private:
+ // Get the current maximum channel count required for a device.
+ // aDevice is an element of mOutputDevices. Graph thread only.
+ struct OutputDeviceEntry;
+ uint32_t AudioOutputChannelCount(const OutputDeviceEntry& aDevice) const;
+ // Get the current maximum channel count for audio output through an
+ // AudioCallbackDriver. Graph thread only.
+ uint32_t PrimaryOutputChannelCount() const;
+
+ public:
+ // Set a new maximum channel count. Graph thread only.
+ void SetMaxOutputChannelCount(uint32_t aMaxChannelCount);
+
+ double AudioOutputLatency();
+
+ /**
+ * The audio input channel count for a MediaTrackGraph is the max of all the
+ * channel counts requested by the listeners. The max channel count is
+ * delivered to the listeners themselves, and they take care of downmixing.
+ */
+ uint32_t AudioInputChannelCount(CubebUtils::AudioDeviceID aID);
+
+ AudioInputType AudioInputDevicePreference(CubebUtils::AudioDeviceID aID);
+
+ double MediaTimeToSeconds(GraphTime aTime) const {
+ NS_ASSERTION(aTime > -TRACK_TIME_MAX && aTime <= TRACK_TIME_MAX,
+ "Bad time");
+ return static_cast<double>(aTime) / GraphRate();
+ }
+
+ /**
+ * Signal to the graph that the thread has paused indefinitly,
+ * or resumed.
+ */
+ void PausedIndefinitly();
+ void ResumedFromPaused();
+
+ /**
+ * Not safe to call off the MediaTrackGraph thread unless monitor is held!
+ */
+ GraphDriver* CurrentDriver() const MOZ_NO_THREAD_SAFETY_ANALYSIS {
+#ifdef DEBUG
+ if (!OnGraphThreadOrNotRunning()) {
+ mMonitor.AssertCurrentThreadOwns();
+ }
+#endif
+ return mDriver;
+ }
+
+ /**
+ * 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.
+ * Monitor must be held.
+ */
+ void SetCurrentDriver(GraphDriver* aDriver) {
+ MOZ_ASSERT_IF(mGraphDriverRunning, InDriverIteration(mDriver));
+ MOZ_ASSERT_IF(!mGraphDriverRunning, NS_IsMainThread());
+ MonitorAutoLock lock(GetMonitor());
+ mDriver = aDriver;
+ }
+
+ GraphDriver* NextDriver() const {
+ MOZ_ASSERT(OnGraphThread());
+ return mNextDriver;
+ }
+
+ bool Switching() const { return NextDriver(); }
+
+ void SwitchAtNextIteration(GraphDriver* aNextDriver);
+
+ Monitor& GetMonitor() { return mMonitor; }
+
+ void EnsureNextIteration() { CurrentDriver()->EnsureNextIteration(); }
+
+ // Capture API. This allows to get a mixed-down output for a window.
+ void RegisterCaptureTrackForWindow(uint64_t aWindowId,
+ ProcessedMediaTrack* aCaptureTrack);
+ void UnregisterCaptureTrackForWindow(uint64_t aWindowId);
+ already_AddRefed<MediaInputPort> ConnectToCaptureTrack(
+ uint64_t aWindowId, MediaTrack* aMediaTrack);
+
+ Watchable<GraphTime>& CurrentTime() override;
+
+ /**
+ * Interrupt any JS running on the graph thread.
+ * Called on the main thread when shutting down the graph.
+ */
+ void InterruptJS();
+
+ class TrackSet {
+ public:
+ class iterator {
+ public:
+ explicit iterator(MediaTrackGraphImpl& aGraph)
+ : mGraph(&aGraph), mArrayNum(-1), mArrayIndex(0) {
+ ++(*this);
+ }
+ iterator() : mGraph(nullptr), mArrayNum(2), mArrayIndex(0) {}
+ MediaTrack* 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<MediaTrack*>* Array() {
+ return mArrayNum == 0 ? &mGraph->mTracks : &mGraph->mSuspendedTracks;
+ }
+ MediaTrackGraphImpl* mGraph;
+ int mArrayNum;
+ uint32_t mArrayIndex;
+ };
+
+ explicit TrackSet(MediaTrackGraphImpl& aGraph) : mGraph(aGraph) {}
+ iterator begin() { return iterator(mGraph); }
+ iterator end() { return iterator(); }
+
+ private:
+ MediaTrackGraphImpl& mGraph;
+ };
+ TrackSet AllTracks() { return TrackSet(*this); }
+
+ // Data members
+
+ /**
+ * The ID of the inner Window which uses this graph, or zero for offline
+ * graphs.
+ */
+ const uint64_t mWindowID;
+ /*
+ * If set, the GraphRunner class handles handing over data from audio
+ * callbacks to a common single thread, shared across GraphDrivers.
+ */
+ RefPtr<GraphRunner> mGraphRunner;
+
+ /**
+ * Main-thread view of the number of tracks in this graph, for lifetime
+ * management.
+ *
+ * When this becomes zero, the graph is marked as forbidden to add more
+ * tracks to. It will be shut down shortly after.
+ */
+ size_t mMainThreadTrackCount = 0;
+
+ /**
+ * Main-thread view of the number of ports in this graph, to catch bugs.
+ *
+ * When this becomes zero, and mMainThreadTrackCount is 0, the graph is
+ * marked as forbidden to add more control messages to. It will be shut down
+ * shortly after.
+ */
+ size_t mMainThreadPortCount = 0;
+
+ /**
+ * 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 track can take some time to shut down.
+ * Accessed on both the main thread and the graph thread; both read and write.
+ * Must hold monitor to access it.
+ */
+ RefPtr<GraphDriver> mDriver;
+
+ // Set during an iteration to switch driver after the iteration has finished.
+ // Should the current iteration be the last iteration, the next driver will be
+ // discarded. Access through SwitchAtNextIteration()/NextDriver(). Graph
+ // thread only.
+ RefPtr<GraphDriver> mNextDriver;
+
+ // 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 track.
+ * References are maintained manually to simplify reordering without
+ * unnecessary thread-safe refcount changes.
+ * Must satisfy OnGraphThreadOrNotRunning().
+ */
+ nsTArray<MediaTrack*> mTracks;
+ /**
+ * This stores MediaTracks that are part of suspended AudioContexts.
+ * mTracks and mSuspendTracks are disjoint sets: a track is either suspended
+ * or not suspended. Suspended tracks are not ordered in UpdateTrackOrder,
+ * and are therefore not doing any processing.
+ * Must satisfy OnGraphThreadOrNotRunning().
+ */
+ nsTArray<MediaTrack*> mSuspendedTracks;
+ /**
+ * Tracks from mFirstCycleBreaker to the end of mTracks 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 track 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;
+ /**
+ * The end of the current iteration. Only access on the graph thread.
+ */
+ GraphTime mIterationEndTime = 0;
+ /**
+ * The graph should stop processing at this time.
+ */
+ GraphTime mEndTime;
+ /**
+ * Date of the last time we updated the main thread with the graph state.
+ */
+ TimeStamp mLastMainThreadUpdate;
+ /**
+ * Number of active MediaInputPorts
+ */
+ int32_t mPortCount;
+ /**
+ * Runnables to run after the next update to main thread state, but that are
+ * still waiting for the next iteration to finish.
+ */
+ nsTArray<nsCOMPtr<nsIRunnable>> mPendingUpdateRunnables;
+
+ /**
+ * List of resume operations waiting for a switch to an AudioCallbackDriver.
+ */
+ class PendingResumeOperation {
+ public:
+ explicit PendingResumeOperation(
+ AudioContextOperationControlMessage* aMessage);
+ void Apply(MediaTrackGraphImpl* aGraph);
+ void Abort();
+ MediaTrack* DestinationTrack() const { return mDestinationTrack; }
+
+ private:
+ RefPtr<MediaTrack> mDestinationTrack;
+ nsTArray<RefPtr<MediaTrack>> mTracks;
+ MozPromiseHolder<AudioContextOperationPromise> mHolder;
+ };
+ AutoTArray<PendingResumeOperation, 1> mPendingResumeOperations;
+
+ // mMonitor guards the data below.
+ // MediaTrackGraph 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 control message 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<TrackUpdate> mTrackUpdates MOZ_GUARDED_BY(mMonitor);
+ /**
+ * Runnables to run after the next update to main thread state.
+ */
+ nsTArray<nsCOMPtr<nsIRunnable>> mUpdateRunnables MOZ_GUARDED_BY(mMonitor);
+ /**
+ * A list of batches of messages to process. Each batch is processed
+ * as an atomic unit.
+ */
+ /*
+ * Message queue processed by the MTG 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 MOZ_GUARDED_BY(mMonitor);
+
+ /* True if there will messages to process if we swap the message queues. */
+ bool MessagesQueued() const MOZ_REQUIRES(mMonitor) {
+ 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 tracks, and exits. The next RunInStableState()
+ * checks if there are new pending messages from the main thread (true only
+ * if new track creation raced with shutdown); if there are, it revives
+ * RunThread(), otherwise it commits to shutting down the graph. New track
+ * 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, completion of a non-realtime
+ * graph, or document unload. 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 track is
+ * destroyed, the graph object is deleted.
+ *
+ * This should be kept in sync with the LifecycleState_str array in
+ * MediaTrackGraph.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 tracks
+ // 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 tracks.
+ LIFECYCLE_WAITING_FOR_TRACK_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 MOZ_GUARDED_BY(mMonitor);
+ LifecycleState& LifecycleStateRef() MOZ_NO_THREAD_SAFETY_ANALYSIS {
+#if DEBUG
+ if (mGraphDriverRunning) {
+ mMonitor.AssertCurrentThreadOwns();
+ } else {
+ MOZ_ASSERT(NS_IsMainThread());
+ }
+#endif
+ return mLifecycleState;
+ }
+ const LifecycleState& LifecycleStateRef() const
+ MOZ_NO_THREAD_SAFETY_ANALYSIS {
+#if DEBUG
+ if (mGraphDriverRunning) {
+ mMonitor.AssertCurrentThreadOwns();
+ } else {
+ MOZ_ASSERT(NS_IsMainThread());
+ }
+#endif
+ return mLifecycleState;
+ }
+
+ /**
+ * True once the graph thread has received the message from ForceShutDown().
+ * This is checked in the decision to shut down the
+ * graph thread so that control messages dispatched before forced shutdown
+ * are processed on the graph thread.
+ * Only set on the graph thread.
+ * Can be read safely on the thread currently owning the graph, as indicated
+ * by mLifecycleState.
+ */
+ bool mForceShutDownReceived = false;
+ /**
+ * true when InterruptJS() has been called, because shutdown (normal or
+ * forced) has commenced. Set on the main thread under mMonitor and read on
+ * the graph thread under mMonitor.
+ **/
+ bool mInterruptJSCalled MOZ_GUARDED_BY(mMonitor) = false;
+
+ /**
+ * Remove this blocker to unblock shutdown.
+ * Only accessed on the main thread.
+ **/
+ RefPtr<media::ShutdownBlocker> mShutdownBlocker;
+
+ /**
+ * True when we have posted an event to the main thread to run
+ * RunInStableState() and the event hasn't run yet.
+ * Accessed on both main and MTG thread, mMonitor must be held.
+ */
+ bool mPostedRunInStableStateEvent MOZ_GUARDED_BY(mMonitor);
+
+ /**
+ * The JSContext of the graph thread. Set under mMonitor on only the graph
+ * or GraphRunner thread. Once set this does not change until reset when
+ * the thread is about to exit. Read under mMonitor on the main thread to
+ * interrupt running JS for forced shutdown.
+ **/
+ JSContext* mJSContext MOZ_GUARDED_BY(mMonitor) = nullptr;
+
+ // 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<ControlMessageInterface>> mCurrentTaskMessageQueue;
+ /**
+ * True from when RunInStableState sets mLifecycleState to LIFECYCLE_RUNNING,
+ * until RunInStableState has determined that mLifecycleState is >
+ * LIFECYCLE_RUNNING.
+ */
+ Atomic<bool> mGraphDriverRunning;
+ /**
+ * True when a stable state runner has been posted to the appshell to run
+ * RunInStableState at the next stable state.
+ * Only accessed on the main thread.
+ */
+ bool mPostedRunInStableState;
+ /**
+ * True when processing real-time audio/video. False when processing
+ * non-realtime audio.
+ */
+ bool mRealtime;
+ /**
+ * True when a change has happened which requires us to recompute the track
+ * blocking order.
+ */
+ bool mTrackOrderDirty;
+ const RefPtr<nsISerialEventTarget> mMainThread;
+
+ // used to limit graph shutdown time
+ // Only accessed on the main thread.
+ nsCOMPtr<nsITimer> mShutdownTimer;
+
+ protected:
+ virtual ~MediaTrackGraphImpl();
+
+ private:
+ MOZ_DEFINE_MALLOC_SIZE_OF(MallocSizeOf)
+
+ // Set a new native iput device when the current native input device is close.
+ // Main thread only.
+ void SetNewNativeInput();
+
+ /**
+ * 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<MediaTrackGraphImpl> mSelfRef;
+
+ struct WindowAndTrack {
+ uint64_t mWindowId;
+ RefPtr<ProcessedMediaTrack> mCaptureTrackSink;
+ };
+ /**
+ * Track for window audio capture.
+ */
+ nsTArray<WindowAndTrack> mWindowCaptureTracks;
+
+ /**
+ * Main thread unordered record of audio outputs, keyed by Track and output
+ * key. Used to determine when an output device is no longer in use and to
+ * record the volumes corresponding to each key. An array is used as a
+ * simple hash table, on the assumption that the number of outputs is small.
+ */
+ struct TrackAndKey {
+ MOZ_UNSAFE_REF("struct exists only if track exists") MediaTrack* mTrack;
+ void* mKey;
+ };
+ struct TrackKeyDeviceAndVolume {
+ MOZ_UNSAFE_REF("struct exists only if track exists")
+ MediaTrack* const mTrack;
+ void* const mKey;
+ const CubebUtils::AudioDeviceID mDeviceID;
+ float mVolume;
+
+ bool operator==(const TrackAndKey& aTrackAndKey) const {
+ return mTrack == aTrackAndKey.mTrack && mKey == aTrackAndKey.mKey;
+ }
+ };
+ nsTArray<TrackKeyDeviceAndVolume> mAudioOutputParams;
+ /**
+ * Main thread record of which audio output devices are active, keyed by
+ * AudioDeviceID, and their CrossGraphReceivers if any.
+ * mOutputDeviceRefCnts[0] always exists and corresponds to the primary
+ * audio output device, which an AudioCallbackDriver will use if active.
+ * mCount may be zero for the first entry only. */
+ struct DeviceReceiverAndCount {
+ const CubebUtils::AudioDeviceID mDeviceID;
+ // For secondary devices, mReceiver receives audio output.
+ // Null for the primary output device, fed by an AudioCallbackDriver.
+ const RefPtr<CrossGraphReceiver> mReceiver;
+ size_t mRefCnt; // number of mAudioOutputParams entries with this device
+
+ bool operator==(CubebUtils::AudioDeviceID aDeviceID) const {
+ return mDeviceID == aDeviceID;
+ }
+ };
+ nsTArray<DeviceReceiverAndCount> mOutputDeviceRefCnts;
+ /**
+ * Graph thread record of devices to which audio outputs are mixed, keyed by
+ * AudioDeviceID. All tracks that have an audio output to each device are
+ * grouped for mixing their outputs to a single stream.
+ * mOutputDevices[0] always exists and corresponds to the primary audio
+ * output device, which an AudioCallbackDriver will use if active.
+ * An AudioCallbackDriver may be active when no audio outputs have audio
+ * outputs.
+ */
+ struct TrackAndVolume {
+ MOZ_UNSAFE_REF("struct exists only if track exists")
+ MediaTrack* const mTrack;
+ float mVolume;
+
+ bool operator==(const MediaTrack* aTrack) const { return mTrack == aTrack; }
+ };
+ struct OutputDeviceEntry {
+ const CubebUtils::AudioDeviceID mDeviceID;
+ // For secondary devices, mReceiver receives audio output.
+ // Null for the primary output device, fed by an AudioCallbackDriver.
+ const RefPtr<CrossGraphReceiver> mReceiver;
+ /**
+ * Mapping from MediaTrack to volume for all tracks that have their audio
+ * output mixed and written to this output device.
+ */
+ nsTArray<TrackAndVolume> mTrackOutputs;
+
+ bool operator==(CubebUtils::AudioDeviceID aDeviceID) const {
+ return mDeviceID == aDeviceID;
+ }
+ };
+ nsTArray<OutputDeviceEntry> mOutputDevices;
+ /**
+ * mOutputDeviceForAEC identifies the audio output to be passed as the
+ * reverse stream for audio echo cancellation. Used only if a microphone is
+ * active. Graph thread.
+ */
+ CubebUtils::AudioDeviceID mOutputDeviceForAEC = nullptr;
+
+ /**
+ * Global volume scale. Used when running tests so that the output is not too
+ * loud.
+ */
+ const float mGlobalVolume;
+
+#ifdef DEBUG
+ /**
+ * Used to assert when AppendMessage() runs control messages synchronously.
+ */
+ bool mCanRunMessagesSynchronously;
+#endif
+
+ /**
+ * The graph's main-thread observable graph time.
+ * Updated by the stable state runnable after each iteration.
+ */
+ Watchable<GraphTime> mMainThreadGraphTime;
+
+ /**
+ * Set based on mProcessedTime at end of iteration.
+ * Read by stable state runnable on main thread. Protected by mMonitor.
+ */
+ GraphTime mNextMainThreadGraphTime MOZ_GUARDED_BY(mMonitor) = 0;
+
+ /**
+ * Cached audio output latency, in seconds. Main thread only. This is reset
+ * whenever the audio device running this MediaTrackGraph changes.
+ */
+ double mAudioOutputLatency;
+
+ /**
+ * The max audio output channel count the default audio output device
+ * supports. This is cached here because it can be expensive to query. The
+ * cache is invalidated when the device is changed. This is initialized in the
+ * ctor, and the read/write only on the graph thread.
+ */
+ uint32_t mMaxOutputChannelCount;
+
+ public:
+ /**
+ * Manage the native or non-native input device in graph. Main thread only.
+ */
+ DeviceInputTrackManager mDeviceInputTrackManagerMainThread;
+
+ private:
+ /**
+ * Manage the native or non-native input device in graph. Graph thread only.
+ */
+ DeviceInputTrackManager mDeviceInputTrackManagerGraphThread;
+ /**
+ * The mixer that the graph mixes into during an iteration. This is here
+ * rather than on the stack so that its buffer is not allocated each
+ * iteration. Graph thread only.
+ */
+ AudioMixer mMixer;
+};
+
+} // namespace mozilla
+
+#endif /* MEDIATRACKGRAPHIMPL_H_ */