summaryrefslogtreecommitdiffstats
path: root/dom/media/MediaTrackGraph.h
diff options
context:
space:
mode:
Diffstat (limited to 'dom/media/MediaTrackGraph.h')
-rw-r--r--dom/media/MediaTrackGraph.h1345
1 files changed, 1345 insertions, 0 deletions
diff --git a/dom/media/MediaTrackGraph.h b/dom/media/MediaTrackGraph.h
new file mode 100644
index 0000000000..8afeb1dd0d
--- /dev/null
+++ b/dom/media/MediaTrackGraph.h
@@ -0,0 +1,1345 @@
+/* -*- 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_MEDIATRACKGRAPH_H_
+#define MOZILLA_MEDIATRACKGRAPH_H_
+
+#include "AudioSampleFormat.h"
+#include "CubebUtils.h"
+#include "MainThreadUtils.h"
+#include "MediaSegment.h"
+#include "mozilla/LinkedList.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/StateWatching.h"
+#include "mozilla/TaskQueue.h"
+#include "nsAutoRef.h"
+#include "nsIRunnable.h"
+#include "nsTArray.h"
+#include <speex/speex_resampler.h>
+
+class nsIRunnable;
+class nsIGlobalObject;
+class nsPIDOMWindowInner;
+
+namespace mozilla {
+class AsyncLogger;
+class AudioCaptureTrack;
+class CrossGraphTransmitter;
+class CrossGraphReceiver;
+class NativeInputTrack;
+}; // namespace mozilla
+
+extern mozilla::AsyncLogger gMTGTraceLogger;
+
+template <>
+class nsAutoRefTraits<SpeexResamplerState>
+ : public nsPointerRefTraits<SpeexResamplerState> {
+ public:
+ static void Release(SpeexResamplerState* aState) {
+ speex_resampler_destroy(aState);
+ }
+};
+
+namespace mozilla {
+
+extern LazyLogModule gMediaTrackGraphLog;
+
+namespace dom {
+enum class AudioContextOperation : uint8_t;
+enum class AudioContextOperationFlags;
+enum class AudioContextState : uint8_t;
+} // namespace dom
+
+/*
+ * MediaTrackGraph is a framework for synchronized audio/video processing
+ * and playback. It is designed to be used by other browser components such as
+ * HTML media elements, media capture APIs, real-time media streaming APIs,
+ * multitrack media APIs, and advanced audio APIs.
+ *
+ * The MediaTrackGraph uses a dedicated thread to process media --- the media
+ * graph thread. This ensures that we can process media through the graph
+ * without blocking on main-thread activity. The media graph is only modified
+ * on the media graph thread, to ensure graph changes can be processed without
+ * interfering with media processing. All interaction with the media graph
+ * thread is done with message passing.
+ *
+ * APIs that modify the graph or its properties are described as "control APIs".
+ * These APIs are asynchronous; they queue graph changes internally and
+ * those changes are processed all-at-once by the MediaTrackGraph. The
+ * MediaTrackGraph monitors the main thread event loop via
+ * nsIAppShell::RunInStableState to ensure that graph changes from a single
+ * event loop task are always processed all together. Control APIs should only
+ * be used on the main thread, currently; we may be able to relax that later.
+ *
+ * To allow precise synchronization of times in the control API, the
+ * MediaTrackGraph maintains a "media timeline". Control APIs that take or
+ * return times use that timeline. Those times never advance during
+ * an event loop task. This time is returned by
+ * MediaTrackGraph::GetCurrentTime().
+ *
+ * Media decoding, audio processing and media playback use thread-safe APIs to
+ * the media graph to ensure they can continue while the main thread is blocked.
+ *
+ * When the graph is changed, we may need to throw out buffered data and
+ * reprocess it. This is triggered automatically by the MediaTrackGraph.
+ */
+
+class AudioProcessingTrack;
+class AudioNodeEngine;
+class AudioNodeExternalInputTrack;
+class AudioNodeTrack;
+class DirectMediaTrackListener;
+class ForwardedInputTrack;
+class MediaInputPort;
+class MediaTrack;
+class MediaTrackGraph;
+class MediaTrackGraphImpl;
+class MediaTrackListener;
+class DeviceInputConsumerTrack;
+class DeviceInputTrack;
+class ProcessedMediaTrack;
+class SourceMediaTrack;
+
+class AudioDataListenerInterface {
+ protected:
+ // Protected destructor, to discourage deletion outside of Release():
+ virtual ~AudioDataListenerInterface() = default;
+
+ public:
+ /**
+ * Number of audio input channels.
+ */
+ virtual uint32_t RequestedInputChannelCount(MediaTrackGraph* aGraph) = 0;
+
+ /**
+ * Whether the underlying audio device is used for voice input.
+ */
+ virtual bool IsVoiceInput(MediaTrackGraph* aGraph) const = 0;
+ /**
+ * Called when the underlying audio device has changed.
+ */
+ virtual void DeviceChanged(MediaTrackGraph* aGraph) = 0;
+
+ /**
+ * Called when the underlying audio device is being closed.
+ */
+ virtual void Disconnect(MediaTrackGraph* aGraph) = 0;
+};
+
+class AudioDataListener : public AudioDataListenerInterface {
+ protected:
+ // Protected destructor, to discourage deletion outside of Release():
+ virtual ~AudioDataListener() = default;
+
+ public:
+ NS_INLINE_DECL_THREADSAFE_REFCOUNTING(AudioDataListener)
+};
+
+/**
+ * This is a base class for main-thread listener callbacks.
+ * This callback is invoked on the main thread when the main-thread-visible
+ * state of a track has changed.
+ *
+ * These methods are called with the media graph monitor held, so
+ * reentry into general media graph methods is not possible.
+ * You should do something non-blocking and non-reentrant (e.g. dispatch an
+ * event) and return. NS_DispatchToCurrentThread would be a good choice.
+ * The listener is allowed to synchronously remove itself from the track, but
+ * not add or remove any other listeners.
+ */
+class MainThreadMediaTrackListener {
+ public:
+ virtual void NotifyMainThreadTrackEnded() = 0;
+};
+
+/**
+ * Helper struct used to keep track of memory usage by AudioNodes.
+ */
+struct AudioNodeSizes {
+ AudioNodeSizes() : mTrack(0), mEngine(0), mNodeType() {}
+ size_t mTrack;
+ size_t mEngine;
+ const char* mNodeType;
+};
+
+/**
+ * Describes how a track should be disabled.
+ *
+ * ENABLED Not disabled.
+ * SILENCE_BLACK Audio data is turned into silence, video frames are made
+ * black.
+ * SILENCE_FREEZE Audio data is turned into silence, video freezes at
+ * last frame.
+ */
+enum class DisabledTrackMode { ENABLED, SILENCE_BLACK, SILENCE_FREEZE };
+
+/**
+ * A track of audio or video data. The media type must be known at construction
+ * and cannot change. All tracks progress at the same rate --- "real time".
+ * Tracks cannot seek. The only operation readers can perform on a track is to
+ * read the next data.
+ *
+ * Consumers of a track can be reading from it at different offsets, but that
+ * should only happen due to the order in which consumers are being run.
+ * Those offsets must not diverge in the long term, otherwise we would require
+ * unbounded buffering.
+ *
+ * (DEPRECATED to be removed in bug 1581074)
+ * Tracks can be in a "blocked" state. While blocked, a track does not
+ * produce data. A track can be explicitly blocked via the control API,
+ * or implicitly blocked by whatever's generating it (e.g. an underrun in the
+ * source resource), or implicitly blocked because something consuming it
+ * blocks, or implicitly because it has ended.
+ *
+ * A track can be in an "ended" state. "Ended" tracks are permanently blocked.
+ * The "ended" state is terminal.
+ *
+ * Transitions into and out of the "blocked" and "ended" states are managed
+ * by the MediaTrackGraph on the media graph thread.
+ *
+ * We buffer media data ahead of the consumers' reading offsets. It is possible
+ * to have buffered data but still be blocked.
+ *
+ * Any track can have its audio or video playing when requested. The media
+ * track graph plays audio by constructing audio output tracks as necessary.
+ * Video is played through a DirectMediaTrackListener managed by
+ * VideoStreamTrack.
+ *
+ * The data in a track is managed by mSegment. The segment starts at GraphTime
+ * mStartTime and encodes its own TrackTime duration.
+ *
+ * Tracks are explicitly managed. The client creates them via
+ * MediaTrackGraph::Create{Source|ForwardedInput}Track, and releases them by
+ * calling Destroy() when no longer needed (actual destruction will be
+ * deferred). The actual object is owned by the MediaTrackGraph. The basic idea
+ * is that main thread objects will keep Tracks alive as long as necessary
+ * (using the cycle collector to clean up whenever needed).
+ *
+ * We make them refcounted only so that track-related messages with
+ * MediaTrack* pointers can be sent to the main thread safely.
+ *
+ * The lifetimes of MediaTracks are controlled from the main thread.
+ * For MediaTracks exposed to the DOM, the lifetime is controlled by the DOM
+ * wrapper; the DOM wrappers own their associated MediaTracks. When a DOM
+ * wrapper is destroyed, it sends a Destroy message for the associated
+ * MediaTrack and clears its reference (the last main-thread reference to
+ * the object). When the Destroy message is processed on the graph thread we
+ * immediately release the affected objects (disentangling them from other
+ * objects as necessary).
+ *
+ * This could cause problems for media processing if a MediaTrack is destroyed
+ * while a downstream MediaTrack is still using it. Therefore the DOM wrappers
+ * must keep upstream MediaTracks alive as long as they could be used in the
+ * media graph.
+ *
+ * At any time, however, a set of MediaTrack wrappers could be collected via
+ * cycle collection. Destroy messages will be sent for those objects in
+ * arbitrary order and the MediaTrackGraph has to be able to handle this.
+ */
+class MediaTrack : public mozilla::LinkedListElement<MediaTrack> {
+ public:
+ NS_INLINE_DECL_THREADSAFE_REFCOUNTING(MediaTrack)
+
+ MediaTrack(TrackRate aSampleRate, MediaSegment::Type aType,
+ MediaSegment* aSegment);
+
+ // The sample rate of the graph.
+ const TrackRate mSampleRate;
+ const MediaSegment::Type mType;
+
+ protected:
+ // Protected destructor, to discourage deletion outside of Release():
+ virtual ~MediaTrack();
+
+ public:
+ /**
+ * Returns the graph that owns this track.
+ */
+ MediaTrackGraphImpl* GraphImpl();
+ const MediaTrackGraphImpl* GraphImpl() const;
+ MediaTrackGraph* Graph() { return mGraph; }
+ const MediaTrackGraph* Graph() const { return mGraph; }
+ /**
+ * Sets the graph that owns this track. Should only be called once.
+ */
+ void SetGraphImpl(MediaTrackGraphImpl* aGraph);
+ void SetGraphImpl(MediaTrackGraph* aGraph);
+
+ // Control API.
+ void AddAudioOutput(void* aKey, const AudioDeviceInfo* aSink);
+ void AddAudioOutput(void* aKey, CubebUtils::AudioDeviceID aDeviceID,
+ TrackRate aPreferredSampleRate);
+ void SetAudioOutputVolume(void* aKey, float aVolume);
+ void RemoveAudioOutput(void* aKey);
+ // Explicitly suspend. Useful for example if a media element is pausing
+ // and we need to stop its track emitting its buffered data. As soon as the
+ // Suspend message reaches the graph, the track stops processing. It
+ // ignores its inputs and produces silence/no video until Resumed. Its
+ // current time does not advance.
+ void Suspend();
+ void Resume();
+ // Events will be dispatched by calling methods of aListener.
+ virtual void AddListener(MediaTrackListener* aListener);
+ virtual RefPtr<GenericPromise> RemoveListener(MediaTrackListener* aListener);
+
+ /**
+ * Adds aListener to the source track of this track.
+ * When the MediaTrackGraph processes the added listener, it will traverse
+ * the graph and add it to the track's source track.
+ * Note that the listener will be notified on the MediaTrackGraph thread
+ * with whether the installation of it at the source was successful or not.
+ */
+ void AddDirectListener(DirectMediaTrackListener* aListener);
+
+ /**
+ * Removes aListener from the source track of this track.
+ * Note that the listener has already been removed if the link between the
+ * source and this track has been broken. The caller doesn't have to care
+ * about this, removing when the source cannot be found, or when the listener
+ * had already been removed does nothing.
+ */
+ void RemoveDirectListener(DirectMediaTrackListener* aListener);
+
+ // A disabled track has video replaced by black, and audio replaced by
+ // silence.
+ void SetDisabledTrackMode(DisabledTrackMode aMode);
+
+ // End event will be notified by calling methods of aListener. It is the
+ // responsibility of the caller to remove aListener before it is destroyed.
+ void AddMainThreadListener(MainThreadMediaTrackListener* aListener);
+ // It's safe to call this even if aListener is not currently a listener;
+ // the call will be ignored.
+ void RemoveMainThreadListener(MainThreadMediaTrackListener* aListener) {
+ MOZ_ASSERT(NS_IsMainThread());
+ MOZ_ASSERT(aListener);
+ mMainThreadListeners.RemoveElement(aListener);
+ }
+
+ /**
+ * Append to the message queue a control message to execute a given lambda
+ * function with no parameters. The queue is drained during
+ * RunInStableState(). 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) {
+ QueueMessage(WrapUnique(
+ new ControlMessageWithNoShutdown(std::forward<Function>(aFunction))));
+ }
+
+ enum class IsInShutdown { No, Yes };
+ /**
+ * 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) {
+ QueueMessage(WrapUnique(
+ new ControlOrShutdownMessage(std::forward<Function>(aFunction))));
+ }
+
+ /**
+ * Ensure a runnable will run on the main thread after running all pending
+ * updates that were sent from the graph thread or will be sent before the
+ * graph thread receives the next graph update.
+ *
+ * If the graph has been shut down or destroyed, then the runnable will be
+ * dispatched to the event queue immediately. (There are no pending updates
+ * in this situation.)
+ *
+ * Main thread only.
+ */
+ void RunAfterPendingUpdates(already_AddRefed<nsIRunnable> aRunnable);
+
+ // Signal that the client is done with this MediaTrack. It will be deleted
+ // later.
+ virtual void Destroy();
+
+ // Returns the main-thread's view of how much data has been processed by
+ // this track.
+ TrackTime GetCurrentTime() const {
+ NS_ASSERTION(NS_IsMainThread(), "Call only on main thread");
+ return mMainThreadCurrentTime;
+ }
+ // Return the main thread's view of whether this track has ended.
+ bool IsEnded() const {
+ NS_ASSERTION(NS_IsMainThread(), "Call only on main thread");
+ return mMainThreadEnded;
+ }
+
+ bool IsDestroyed() const {
+ NS_ASSERTION(NS_IsMainThread(), "Call only on main thread");
+ return mMainThreadDestroyed;
+ }
+
+ friend class MediaTrackGraphImpl;
+ friend class MediaInputPort;
+ friend class AudioNodeExternalInputTrack;
+
+ virtual AudioProcessingTrack* AsAudioProcessingTrack() { return nullptr; }
+ virtual SourceMediaTrack* AsSourceTrack() { return nullptr; }
+ virtual ProcessedMediaTrack* AsProcessedTrack() { return nullptr; }
+ virtual AudioNodeTrack* AsAudioNodeTrack() { return nullptr; }
+ virtual ForwardedInputTrack* AsForwardedInputTrack() { return nullptr; }
+ virtual CrossGraphTransmitter* AsCrossGraphTransmitter() { return nullptr; }
+ virtual CrossGraphReceiver* AsCrossGraphReceiver() { return nullptr; }
+ virtual DeviceInputTrack* AsDeviceInputTrack() { return nullptr; }
+ virtual DeviceInputConsumerTrack* AsDeviceInputConsumerTrack() {
+ return nullptr;
+ }
+
+ // These Impl methods perform the core functionality of the control methods
+ // above, on the media graph thread.
+ /**
+ * Stop all track activity and disconnect it from all inputs and outputs.
+ * This must be idempotent.
+ */
+ virtual void DestroyImpl();
+ TrackTime GetEnd() const;
+
+ /**
+ * Removes all direct listeners and signals to them that they have been
+ * uninstalled.
+ */
+ virtual void RemoveAllDirectListenersImpl() {}
+ void RemoveAllResourcesAndListenersImpl();
+
+ virtual void AddListenerImpl(already_AddRefed<MediaTrackListener> aListener);
+ virtual void RemoveListenerImpl(MediaTrackListener* aListener);
+ virtual void AddDirectListenerImpl(
+ already_AddRefed<DirectMediaTrackListener> aListener);
+ virtual void RemoveDirectListenerImpl(DirectMediaTrackListener* aListener);
+ virtual void SetDisabledTrackModeImpl(DisabledTrackMode aMode);
+
+ void AddConsumer(MediaInputPort* aPort) { mConsumers.AppendElement(aPort); }
+ void RemoveConsumer(MediaInputPort* aPort) {
+ mConsumers.RemoveElement(aPort);
+ }
+ GraphTime StartTime() const { return mStartTime; }
+ bool Ended() const { return mEnded; }
+
+ // Returns the current number of channels this track contains if it's an audio
+ // track. Calling this on a video track will trip assertions. Graph thread
+ // only.
+ virtual uint32_t NumberOfChannels() const = 0;
+
+ // The DisabledTrackMode after combining the explicit mode and that of the
+ // input, if any.
+ virtual DisabledTrackMode CombinedDisabledMode() const {
+ return mDisabledMode;
+ }
+
+ template <class SegmentType>
+ SegmentType* GetData() const {
+ if (!mSegment) {
+ return nullptr;
+ }
+ if (mSegment->GetType() != SegmentType::StaticType()) {
+ return nullptr;
+ }
+ return static_cast<SegmentType*>(mSegment.get());
+ }
+ MediaSegment* GetData() const { return mSegment.get(); }
+
+ double TrackTimeToSeconds(TrackTime aTime) const {
+ NS_ASSERTION(0 <= aTime && aTime <= TRACK_TIME_MAX, "Bad time");
+ return static_cast<double>(aTime) / mSampleRate;
+ }
+ int64_t TrackTimeToMicroseconds(TrackTime aTime) const {
+ NS_ASSERTION(0 <= aTime && aTime <= TRACK_TIME_MAX, "Bad time");
+ return (aTime * 1000000) / mSampleRate;
+ }
+ TrackTime SecondsToNearestTrackTime(double aSeconds) const {
+ NS_ASSERTION(0 <= aSeconds && aSeconds <= TRACK_TICKS_MAX / TRACK_RATE_MAX,
+ "Bad seconds");
+ return mSampleRate * aSeconds + 0.5;
+ }
+ TrackTime MicrosecondsToTrackTimeRoundDown(int64_t aMicroseconds) const {
+ return (aMicroseconds * mSampleRate) / 1000000;
+ }
+
+ TrackTicks TimeToTicksRoundUp(TrackRate aRate, TrackTime aTime) const {
+ return RateConvertTicksRoundUp(aRate, mSampleRate, aTime);
+ }
+ TrackTime TicksToTimeRoundDown(TrackRate aRate, TrackTicks aTicks) const {
+ return RateConvertTicksRoundDown(mSampleRate, aRate, aTicks);
+ }
+ /**
+ * Convert graph time to track time. aTime must be <= mStateComputedTime
+ * to ensure we know exactly how much time this track will be blocked during
+ * the interval.
+ */
+ TrackTime GraphTimeToTrackTimeWithBlocking(GraphTime aTime) const;
+ /**
+ * Convert graph time to track time. This assumes there is no blocking time
+ * to take account of, which is always true except between a track
+ * having its blocking time calculated in UpdateGraph and its blocking time
+ * taken account of in UpdateCurrentTimeForTracks.
+ */
+ TrackTime GraphTimeToTrackTime(GraphTime aTime) const;
+ /**
+ * Convert track time to graph time. This assumes there is no blocking time
+ * to take account of, which is always true except between a track
+ * having its blocking time calculated in UpdateGraph and its blocking time
+ * taken account of in UpdateCurrentTimeForTracks.
+ */
+ GraphTime TrackTimeToGraphTime(TrackTime aTime) const;
+
+ virtual void ApplyTrackDisabling(MediaSegment* aSegment,
+ MediaSegment* aRawSegment = nullptr);
+
+ // Return true if the main thread needs to observe updates from this track.
+ virtual bool MainThreadNeedsUpdates() const { return true; }
+
+ virtual size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const;
+ virtual size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const;
+
+ bool IsSuspended() const { return mSuspendedCount > 0; }
+ /**
+ * Increment suspend count and move it to GraphImpl()->mSuspendedTracks if
+ * necessary. Graph thread.
+ */
+ void IncrementSuspendCount();
+ /**
+ * Increment suspend count on aTrack and move it to GraphImpl()->mTracks if
+ * necessary. GraphThread.
+ */
+ virtual void DecrementSuspendCount();
+
+ void AssertOnGraphThread() const;
+ void AssertOnGraphThreadOrNotRunning() const;
+
+ /**
+ * For use during ProcessedMediaTrack::ProcessInput() or
+ * MediaTrackListener callbacks, when graph state cannot be changed.
+ * Queues a control message to execute a given lambda function with no
+ * parameters after processing, at a time when graph state can be changed.
+ * The lambda will always be executed before handing control of the graph
+ * to the main thread for shutdown.
+ * Graph thread.
+ */
+ template <typename Function>
+ void RunAfterProcessing(Function&& aFunction) {
+ RunMessageAfterProcessing(WrapUnique(
+ new ControlMessageWithNoShutdown(std::forward<Function>(aFunction))));
+ }
+
+ class ControlMessageInterface;
+
+ protected:
+ // Called on graph thread either during destroy handling or before handing
+ // graph control to the main thread to release tracks.
+ virtual void OnGraphThreadDone() {}
+
+ // |AdvanceTimeVaryingValuesToCurrentTime| will be override in
+ // SourceMediaTrack.
+ virtual void AdvanceTimeVaryingValuesToCurrentTime(GraphTime aCurrentTime,
+ GraphTime aBlockedTime);
+
+ private:
+ template <typename Function>
+ class ControlMessageWithNoShutdown;
+ template <typename Function>
+ class ControlOrShutdownMessage;
+
+ void QueueMessage(UniquePtr<ControlMessageInterface> aMessage);
+ void RunMessageAfterProcessing(UniquePtr<ControlMessageInterface> aMessage);
+
+ void NotifyMainThreadListeners() {
+ NS_ASSERTION(NS_IsMainThread(), "Call only on main thread");
+
+ for (int32_t i = mMainThreadListeners.Length() - 1; i >= 0; --i) {
+ mMainThreadListeners[i]->NotifyMainThreadTrackEnded();
+ }
+ mMainThreadListeners.Clear();
+ }
+
+ bool ShouldNotifyTrackEnded() {
+ NS_ASSERTION(NS_IsMainThread(), "Call only on main thread");
+ if (!mMainThreadEnded || mEndedNotificationSent) {
+ return false;
+ }
+
+ mEndedNotificationSent = true;
+ return true;
+ }
+
+ protected:
+ // Notifies listeners and consumers of the change in disabled mode when the
+ // current combined mode is different from aMode.
+ void NotifyIfDisabledModeChangedFrom(DisabledTrackMode aOldMode);
+
+ // This state is all initialized on the main thread but
+ // otherwise modified only on the media graph thread.
+
+ // Buffered data. The start of the buffer corresponds to mStartTime.
+ // Conceptually the buffer contains everything this track has ever played,
+ // but we forget some prefix of the buffered data to bound the space usage.
+ // Note that this may be null for tracks that never contain data, like
+ // non-external AudioNodeTracks.
+ const UniquePtr<MediaSegment> mSegment;
+
+ // The time when the buffered data could be considered to have started
+ // playing. This increases over time to account for time the track was
+ // blocked before mCurrentTime.
+ GraphTime mStartTime;
+
+ // The time until which we last called mSegment->ForgetUpTo().
+ TrackTime mForgottenTime;
+
+ // True once we've processed mSegment until the end and no more data will be
+ // added. Note that mSegment might still contain data for the current
+ // iteration.
+ bool mEnded;
+
+ // True after track listeners have been notified that this track has ended.
+ bool mNotifiedEnded;
+
+ // Client-set volume of this track
+ nsTArray<RefPtr<MediaTrackListener>> mTrackListeners;
+ nsTArray<MainThreadMediaTrackListener*> mMainThreadListeners;
+ // This track's associated disabled mode. It can either by disabled by frames
+ // being replaced by black, or by retaining the previous frame.
+ DisabledTrackMode mDisabledMode;
+
+ // GraphTime at which this track starts blocking.
+ // This is only valid up to mStateComputedTime. The track is considered to
+ // have not been blocked before mCurrentTime (its mStartTime is
+ // increased as necessary to account for that time instead).
+ GraphTime mStartBlocking;
+
+ // MediaInputPorts to which this is connected
+ nsTArray<MediaInputPort*> mConsumers;
+
+ /**
+ * Number of outstanding suspend operations on this track. Track is
+ * suspended when this is > 0.
+ */
+ int32_t mSuspendedCount;
+
+ // Main-thread views of state
+ TrackTime mMainThreadCurrentTime;
+ bool mMainThreadEnded;
+ bool mEndedNotificationSent;
+ bool mMainThreadDestroyed;
+
+ // Our media track graph. null if destroyed on the graph thread.
+ MediaTrackGraph* mGraph;
+};
+
+/**
+ * This is a track into which a decoder can write audio or video.
+ *
+ * Audio or video can be written on any thread, but you probably want to
+ * always write from the same thread to avoid unexpected interleavings.
+ *
+ * For audio the sample rate of the written data can differ from the sample rate
+ * of the graph itself. Use SetAppendDataSourceRate to inform the track what
+ * rate written audio data will be sampled in.
+ */
+class SourceMediaTrack : public MediaTrack {
+ public:
+ SourceMediaTrack(MediaSegment::Type aType, TrackRate aSampleRate);
+
+ SourceMediaTrack* AsSourceTrack() override { return this; }
+
+ // Main thread only
+
+ /**
+ * Enable or disable pulling.
+ * When pulling is enabled, NotifyPull gets called on the
+ * MediaTrackListeners for this track during the MediaTrackGraph
+ * control loop. Pulling is initially disabled. Due to unavoidable race
+ * conditions, after a call to SetPullingEnabled(false) it is still possible
+ * for a NotifyPull to occur.
+ */
+ void SetPullingEnabled(bool aEnabled);
+
+ // MediaTrackGraph thread only
+ void DestroyImpl() override;
+
+ // Call these on any thread.
+ /**
+ * Call all MediaTrackListeners to request new data via the NotifyPull
+ * API (if enabled).
+ * aDesiredUpToTime (in): end time of new data requested.
+ *
+ * Returns true if new data is about to be added.
+ */
+ bool PullNewData(GraphTime aDesiredUpToTime);
+
+ /**
+ * Extract any state updates pending in the track, and apply them.
+ */
+ void ExtractPendingInput(GraphTime aCurrentTime, GraphTime aDesiredUpToTime);
+
+ /**
+ * All data appended with AppendData() from this point on will be resampled
+ * from aRate to the graph rate.
+ *
+ * Resampling for video does not make sense and is forbidden.
+ */
+ void SetAppendDataSourceRate(TrackRate aRate);
+
+ /**
+ * Append media data to this track. Ownership of aSegment remains with the
+ * caller, but aSegment is emptied. Returns 0 if the data was not appended
+ * because the stream has ended. Returns the duration of the appended data in
+ * the graph's track rate otherwise.
+ */
+ TrackTime AppendData(MediaSegment* aSegment,
+ MediaSegment* aRawSegment = nullptr);
+
+ /**
+ * Clear any data appended with AppendData() that hasn't entered the graph
+ * yet. Returns the duration of the cleared data in the graph's track rate.
+ */
+ TrackTime ClearFutureData();
+
+ /**
+ * Indicate that this track has ended. Do not do any more API calls affecting
+ * this track.
+ */
+ void End();
+
+ void SetDisabledTrackModeImpl(DisabledTrackMode aMode) override;
+
+ uint32_t NumberOfChannels() const override;
+
+ void RemoveAllDirectListenersImpl() override;
+
+ // The value set here is applied in MoveToSegment so we can avoid the
+ // buffering delay in applying the change. See Bug 1443511.
+ void SetVolume(float aVolume);
+ float GetVolumeLocked() MOZ_REQUIRES(mMutex);
+
+ Mutex& GetMutex() MOZ_RETURN_CAPABILITY(mMutex) { return mMutex; }
+
+ friend class MediaTrackGraphImpl;
+
+ protected:
+ enum TrackCommands : uint32_t;
+
+ virtual ~SourceMediaTrack();
+
+ /**
+ * Data to cater for appending media data to this track.
+ */
+ struct TrackData {
+ // Sample rate of the input data.
+ TrackRate mInputRate;
+ // Resampler if the rate of the input track does not match the
+ // MediaTrackGraph's.
+ nsAutoRef<SpeexResamplerState> mResampler;
+ uint32_t mResamplerChannelCount;
+ // Each time the track updates are flushed to the media graph thread,
+ // the segment buffer is emptied.
+ UniquePtr<MediaSegment> mData;
+ // True once the producer has signaled that no more data is coming.
+ bool mEnded;
+ // True if the producer of this track is having data pulled by the graph.
+ bool mPullingEnabled;
+ // True if the graph has notified this track that it will not be used
+ // again on the graph thread.
+ bool mGraphThreadDone;
+ };
+
+ bool NeedsMixing();
+
+ void ResampleAudioToGraphSampleRate(MediaSegment* aSegment)
+ MOZ_REQUIRES(mMutex);
+
+ void AddDirectListenerImpl(
+ already_AddRefed<DirectMediaTrackListener> aListener) override;
+ void RemoveDirectListenerImpl(DirectMediaTrackListener* aListener) override;
+
+ /**
+ * Notify direct consumers of new data to this track.
+ * The data doesn't have to be resampled (though it may be). This is called
+ * from AppendData on the thread providing the data, and will call
+ * the Listeners on this thread.
+ */
+ void NotifyDirectConsumers(MediaSegment* aSegment) MOZ_REQUIRES(mMutex);
+
+ void OnGraphThreadDone() override {
+ MutexAutoLock lock(mMutex);
+ if (!mUpdateTrack) {
+ return;
+ }
+ mUpdateTrack->mGraphThreadDone = true;
+ if (!mUpdateTrack->mData) {
+ return;
+ }
+ mUpdateTrack->mData->Clear();
+ }
+
+ virtual void AdvanceTimeVaryingValuesToCurrentTime(
+ GraphTime aCurrentTime, GraphTime aBlockedTime) override;
+
+ // This must be acquired *before* MediaTrackGraphImpl's lock, if they are
+ // held together.
+ Mutex mMutex;
+ // protected by mMutex
+ float mVolume MOZ_GUARDED_BY(mMutex) = 1.0;
+ UniquePtr<TrackData> mUpdateTrack MOZ_GUARDED_BY(mMutex);
+ // This track's associated disabled mode for uses on the producing thread.
+ // It can either by disabled by frames being replaced by black, or by
+ // retaining the previous frame.
+ DisabledTrackMode mDirectDisabledMode MOZ_GUARDED_BY(mMutex) =
+ DisabledTrackMode::ENABLED;
+ nsTArray<RefPtr<DirectMediaTrackListener>> mDirectTrackListeners
+ MOZ_GUARDED_BY(mMutex);
+};
+
+/**
+ * A ref-counted wrapper of a MediaTrack that allows multiple users to share a
+ * reference to the same MediaTrack with the purpose of being guaranteed that
+ * the graph it is in is kept alive.
+ *
+ * Automatically suspended on creation and destroyed on destruction. Main thread
+ * only.
+ */
+struct SharedDummyTrack {
+ NS_INLINE_DECL_REFCOUNTING(SharedDummyTrack)
+ explicit SharedDummyTrack(MediaTrack* aTrack) : mTrack(aTrack) {
+ mTrack->Suspend();
+ }
+ const RefPtr<MediaTrack> mTrack;
+
+ private:
+ ~SharedDummyTrack() { mTrack->Destroy(); }
+};
+
+/**
+ * Represents a connection between a ProcessedMediaTrack and one of its
+ * input tracks.
+ * We make these refcounted so that track-related messages with MediaInputPort*
+ * pointers can be sent to the main thread safely.
+ *
+ * When a port's source or destination track dies, the track's DestroyImpl
+ * calls MediaInputPort::Disconnect to disconnect the port from
+ * the source and destination tracks.
+ *
+ * The lifetimes of MediaInputPort are controlled from the main thread.
+ * The media graph adds a reference to the port. When a MediaInputPort is no
+ * longer needed, main-thread code sends a Destroy message for the port and
+ * clears its reference (the last main-thread reference to the object). When
+ * the Destroy message is processed on the graph manager thread we disconnect
+ * the port and drop the graph's reference, destroying the object.
+ */
+class MediaInputPort final {
+ private:
+ // Do not call this constructor directly. Instead call
+ // aDest->AllocateInputPort.
+ MediaInputPort(MediaTrackGraphImpl* aGraph, MediaTrack* aSource,
+ ProcessedMediaTrack* aDest, uint16_t aInputNumber,
+ uint16_t aOutputNumber)
+ : mSource(aSource),
+ mDest(aDest),
+ mInputNumber(aInputNumber),
+ mOutputNumber(aOutputNumber),
+ mGraph(aGraph) {
+ MOZ_COUNT_CTOR(MediaInputPort);
+ }
+
+ // Private destructor, to discourage deletion outside of Release():
+ MOZ_COUNTED_DTOR(MediaInputPort)
+
+ public:
+ NS_INLINE_DECL_THREADSAFE_REFCOUNTING(MediaInputPort)
+
+ /**
+ * Disconnects and destroys the port. The caller must not reference this
+ * object again. Main thread.
+ */
+ void Destroy();
+
+ // The remaining methods and members must always be called on the graph thread
+ // from within MediaTrackGraph.cpp.
+
+ void Init();
+ // Called during message processing to trigger removal of this port's source
+ // and destination tracks.
+ void Disconnect();
+
+ MediaTrack* GetSource() const;
+ ProcessedMediaTrack* GetDestination() const;
+
+ uint16_t InputNumber() const { return mInputNumber; }
+ uint16_t OutputNumber() const { return mOutputNumber; }
+
+ struct InputInterval {
+ GraphTime mStart;
+ GraphTime mEnd;
+ bool mInputIsBlocked;
+ };
+ // Find the next time interval starting at or after aTime during which
+ // aPort->mDest is not blocked and aPort->mSource's blocking status does not
+ // change. A null aPort returns a blocked interval starting at aTime.
+ static InputInterval GetNextInputInterval(MediaInputPort const* aPort,
+ GraphTime aTime);
+
+ /**
+ * Returns the graph that owns this port.
+ */
+ MediaTrackGraphImpl* GraphImpl() const;
+ MediaTrackGraph* Graph() const;
+
+ /**
+ * Sets the graph that owns this track. Should only be called once.
+ */
+ void SetGraphImpl(MediaTrackGraphImpl* aGraph);
+
+ /**
+ * Notify the port that the source MediaTrack has been suspended.
+ */
+ void Suspended();
+
+ /**
+ * Notify the port that the source MediaTrack has been resumed.
+ */
+ void Resumed();
+
+ size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const {
+ size_t amount = 0;
+
+ // Not owned:
+ // - mSource
+ // - mDest
+ // - mGraph
+ return amount;
+ }
+
+ size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const {
+ return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+ }
+
+ private:
+ friend class ProcessedMediaTrack;
+ // Never modified after Init()
+ MediaTrack* mSource;
+ ProcessedMediaTrack* mDest;
+ // The input and output numbers are optional, and are currently only used by
+ // Web Audio.
+ const uint16_t mInputNumber;
+ const uint16_t mOutputNumber;
+
+ // Our media track graph
+ MediaTrackGraphImpl* mGraph;
+};
+
+/**
+ * This track processes zero or more input tracks in parallel to produce
+ * its output. The details of how the output is produced are handled by
+ * subclasses overriding the ProcessInput method.
+ */
+class ProcessedMediaTrack : public MediaTrack {
+ public:
+ ProcessedMediaTrack(TrackRate aSampleRate, MediaSegment::Type aType,
+ MediaSegment* aSegment)
+ : MediaTrack(aSampleRate, aType, aSegment),
+ mAutoend(true),
+ mCycleMarker(0) {}
+
+ // Control API.
+ /**
+ * Allocates a new input port attached to source aTrack.
+ * This port can be removed by calling MediaInputPort::Destroy().
+ */
+ already_AddRefed<MediaInputPort> AllocateInputPort(
+ MediaTrack* aTrack, uint16_t aInputNumber = 0,
+ uint16_t aOutputNumber = 0);
+ /**
+ * Queue a message to set the autoend flag on this track (defaults to
+ * true). When this flag is set, and the input track has ended playout
+ * (including if there is no input track), this track automatically
+ * enters the ended state.
+ */
+ virtual void QueueSetAutoend(bool aAutoend);
+
+ ProcessedMediaTrack* AsProcessedTrack() override { return this; }
+
+ friend class MediaTrackGraphImpl;
+
+ // Do not call these from outside MediaTrackGraph.cpp!
+ virtual void AddInput(MediaInputPort* aPort);
+ virtual void RemoveInput(MediaInputPort* aPort) {
+ mInputs.RemoveElement(aPort) || mSuspendedInputs.RemoveElement(aPort);
+ }
+ bool HasInputPort(MediaInputPort* aPort) const {
+ return mInputs.Contains(aPort) || mSuspendedInputs.Contains(aPort);
+ }
+ uint32_t InputPortCount() const {
+ return mInputs.Length() + mSuspendedInputs.Length();
+ }
+ void InputSuspended(MediaInputPort* aPort);
+ void InputResumed(MediaInputPort* aPort);
+ void DestroyImpl() override;
+ void DecrementSuspendCount() override;
+ /**
+ * This gets called after we've computed the blocking states for all
+ * tracks (mBlocked is up to date up to mStateComputedTime).
+ * Also, we've produced output for all tracks up to this one. If this track
+ * is not in a cycle, then all its source tracks have produced data.
+ * Generate output from aFrom to aTo.
+ * This will be called on tracks that have ended. Most track types should
+ * just return immediately if they're ended, but some may wish to update
+ * internal state (see AudioNodeTrack).
+ * ProcessInput is allowed to set mEnded only if ALLOW_END is in aFlags. (This
+ * flag will be set when aTo >= mStateComputedTime, i.e. when we've produced
+ * the last block of data we need to produce.) Otherwise we can get into a
+ * situation where we've determined the track should not block before
+ * mStateComputedTime, but the track ends before mStateComputedTime, violating
+ * the invariant that ended tracks are blocked.
+ */
+ enum { ALLOW_END = 0x01 };
+ virtual void ProcessInput(GraphTime aFrom, GraphTime aTo,
+ uint32_t aFlags) = 0;
+ void SetAutoendImpl(bool aAutoend) { mAutoend = aAutoend; }
+
+ // Only valid after MediaTrackGraphImpl::UpdateTrackOrder() has run.
+ // A DelayNode is considered to break a cycle and so this will not return
+ // true for echo loops, only for muted cycles.
+ bool InMutedCycle() const { return mCycleMarker; }
+
+ // Used by ForwardedInputTrack to propagate the disabled mode along the graph.
+ virtual void OnInputDisabledModeChanged(DisabledTrackMode aMode) {}
+
+ size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const override {
+ size_t amount = MediaTrack::SizeOfExcludingThis(aMallocSizeOf);
+ // Not owned:
+ // - mInputs elements
+ // - mSuspendedInputs elements
+ amount += mInputs.ShallowSizeOfExcludingThis(aMallocSizeOf);
+ amount += mSuspendedInputs.ShallowSizeOfExcludingThis(aMallocSizeOf);
+ return amount;
+ }
+
+ size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const override {
+ return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+ }
+
+ protected:
+ // This state is all accessed only on the media graph thread.
+
+ // The list of all inputs that are not currently suspended.
+ nsTArray<MediaInputPort*> mInputs;
+ // The list of all inputs that are currently suspended.
+ nsTArray<MediaInputPort*> mSuspendedInputs;
+ bool mAutoend;
+ // After UpdateTrackOrder(), mCycleMarker is either 0 or 1 to indicate
+ // whether this track is in a muted cycle. During ordering it can contain
+ // other marker values - see MediaTrackGraphImpl::UpdateTrackOrder().
+ uint32_t mCycleMarker;
+};
+
+/**
+ * There is a single MediaTrackGraph per window.
+ * Additionaly, each OfflineAudioContext object creates its own MediaTrackGraph
+ * object too.
+ */
+class MediaTrackGraph {
+ public:
+ // We ensure that the graph current time advances in multiples of
+ // IdealAudioBlockSize()/AudioStream::PreferredSampleRate(). A track that
+ // never blocks and has the ideal audio rate will produce audio in multiples
+ // of the block size.
+
+ // Initializing a graph that outputs audio can take quite long on some
+ // platforms. Code that want to output audio at some point can express the
+ // fact that they will need an audio track at some point by passing
+ // AUDIO_THREAD_DRIVER when getting an instance of MediaTrackGraph, so that
+ // the graph starts with the right driver.
+ enum GraphDriverType {
+ AUDIO_THREAD_DRIVER,
+ SYSTEM_THREAD_DRIVER,
+ OFFLINE_THREAD_DRIVER
+ };
+ // A MediaTrackGraph running an AudioWorklet must always be run from the
+ // same thread, in order to run js. To acheive this, create the graph with
+ // a SINGLE_THREAD RunType. DIRECT_DRIVER will run the graph directly off
+ // the GraphDriver's thread.
+ enum GraphRunType {
+ DIRECT_DRIVER,
+ SINGLE_THREAD,
+ };
+ static const uint32_t AUDIO_CALLBACK_DRIVER_SHUTDOWN_TIMEOUT = 20 * 1000;
+ static const TrackRate REQUEST_DEFAULT_SAMPLE_RATE = 0;
+ constexpr static const CubebUtils::AudioDeviceID DEFAULT_OUTPUT_DEVICE =
+ nullptr;
+
+ // Main thread only
+ static MediaTrackGraph* GetInstanceIfExists(
+ nsPIDOMWindowInner* aWindow, TrackRate aSampleRate,
+ CubebUtils::AudioDeviceID aPrimaryOutputDeviceID);
+ static MediaTrackGraph* GetInstance(
+ GraphDriverType aGraphDriverRequested, nsPIDOMWindowInner* aWindow,
+ TrackRate aSampleRate, CubebUtils::AudioDeviceID aPrimaryOutputDeviceID);
+ static MediaTrackGraph* CreateNonRealtimeInstance(TrackRate aSampleRate);
+
+ // Idempotent
+ void ForceShutDown();
+
+ virtual void OpenAudioInput(DeviceInputTrack* aTrack) = 0;
+ virtual void CloseAudioInput(DeviceInputTrack* aTrack) = 0;
+
+ // Control API.
+ /**
+ * Create a track that a media decoder (or some other source of
+ * media data, such as a camera) can write to.
+ */
+ SourceMediaTrack* CreateSourceTrack(MediaSegment::Type aType);
+ /**
+ * Create a track that will forward data from its input track.
+ *
+ * A TrackUnionStream can have 0 or 1 input streams. Adding more than that is
+ * an error.
+ *
+ * A TrackUnionStream will end when autoending is enabled (default) and there
+ * is no input, or the input's source is ended. If there is no input and
+ * autoending is disabled, TrackUnionStream will continue to produce silence
+ * for audio or the last video frame for video.
+ */
+ ProcessedMediaTrack* CreateForwardedInputTrack(MediaSegment::Type aType);
+ /**
+ * Create a track that will mix all its audio inputs.
+ */
+ AudioCaptureTrack* CreateAudioCaptureTrack();
+
+ CrossGraphTransmitter* CreateCrossGraphTransmitter(
+ CrossGraphReceiver* aReceiver);
+ CrossGraphReceiver* CreateCrossGraphReceiver(TrackRate aTransmitterRate);
+
+ /**
+ * Add a new track to the graph. Main thread.
+ */
+ void AddTrack(MediaTrack* aTrack);
+
+ /* 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;
+ virtual RefPtr<GraphStartedPromise> NotifyWhenDeviceStarted(
+ CubebUtils::AudioDeviceID aDeviceID) = 0;
+
+ /* From the main thread, suspend, resume or close an AudioContext. Calls
+ * are not counted. Even Resume calls can be more frequent than Suspend
+ * calls.
+ *
+ * aTracks are the tracks of all the AudioNodes of the AudioContext that
+ * need to be suspended or resumed. Suspend and Resume operations on these
+ * tracks are counted. Resume operations must not outnumber Suspends and a
+ * track will not resume until the number of Resume operations matches the
+ * number of Suspends. This array may be empty if, for example, this is a
+ * second consecutive suspend call and all the nodes are already suspended.
+ *
+ * This can possibly pause the graph thread, releasing system resources, if
+ * all tracks have been suspended/closed.
+ *
+ * When the operation is complete, the returned promise is resolved.
+ */
+ using AudioContextOperationPromise =
+ MozPromise<dom::AudioContextState, bool, true>;
+ RefPtr<AudioContextOperationPromise> ApplyAudioContextOperation(
+ MediaTrack* aDestinationTrack, nsTArray<RefPtr<MediaTrack>> aTracks,
+ dom::AudioContextOperation aOperation);
+
+ bool IsNonRealtime() const;
+ /**
+ * Start processing non-realtime for a specific number of ticks.
+ */
+ void StartNonRealtimeProcessing(uint32_t aTicksToProcess);
+
+ /**
+ * NotifyJSContext() is called on the graph thread before content script
+ * runs.
+ */
+ void NotifyJSContext(JSContext* aCx);
+
+ /**
+ * Media graph thread only.
+ * Dispatches a runnable that will run on the main thread after all
+ * main-thread track state has been updated, i.e., during stable state.
+ *
+ * Should only be called during MediaTrackListener callbacks or during
+ * ProcessedMediaTrack::ProcessInput().
+ *
+ * Note that if called during shutdown the runnable will be ignored and
+ * released on main thread.
+ */
+ void DispatchToMainThreadStableState(already_AddRefed<nsIRunnable> aRunnable);
+ /* 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);
+
+ /**
+ * Returns graph sample rate in Hz.
+ */
+ TrackRate GraphRate() const { return mSampleRate; }
+ /**
+ * Returns the ID of the device used for audio output through an
+ * AudioCallbackDriver. This is the device specified when creating the
+ * graph. Can be called on any thread.
+ */
+ CubebUtils::AudioDeviceID PrimaryOutputDeviceID() const {
+ return mPrimaryOutputDeviceID;
+ }
+
+ double AudioOutputLatency();
+
+ void RegisterCaptureTrackForWindow(uint64_t aWindowId,
+ ProcessedMediaTrack* aCaptureTrack);
+ void UnregisterCaptureTrackForWindow(uint64_t aWindowId);
+ already_AddRefed<MediaInputPort> ConnectToCaptureTrack(
+ uint64_t aWindowId, MediaTrack* aMediaTrack);
+
+ void AssertOnGraphThread() const { MOZ_ASSERT(OnGraphThread()); }
+ void AssertOnGraphThreadOrNotRunning() const {
+ MOZ_ASSERT(OnGraphThreadOrNotRunning());
+ }
+
+ /**
+ * Returns a watchable of the graph's main-thread observable graph time.
+ * Main thread only.
+ */
+ virtual Watchable<GraphTime>& CurrentTime() = 0;
+
+ /**
+ * Graph thread function to return the time at which all processing has been
+ * completed. Some tracks may have performed processing beyond this time.
+ */
+ GraphTime ProcessedTime() const;
+ /**
+ * For Graph thread logging.
+ */
+ void* CurrentDriver() const;
+
+ /* Do not call this directly. For users who need to get a DeviceInputTrack,
+ * use DeviceInputTrack::OpenAudio() instead. This should only be used in
+ * DeviceInputTrack to get the existing DeviceInputTrack paired with the given
+ * device in this graph. Main thread only.*/
+ DeviceInputTrack* GetDeviceInputTrackMainThread(
+ CubebUtils::AudioDeviceID aID);
+
+ /* Do not call this directly. This should only be used in DeviceInputTrack to
+ * get the existing NativeInputTrackMain thread only.*/
+ NativeInputTrack* GetNativeInputTrackMainThread();
+
+ protected:
+ explicit MediaTrackGraph(TrackRate aSampleRate,
+ CubebUtils::AudioDeviceID aPrimaryOutputDeviceID)
+ : mSampleRate(aSampleRate),
+ mPrimaryOutputDeviceID(aPrimaryOutputDeviceID) {
+ MOZ_COUNT_CTOR(MediaTrackGraph);
+ }
+ MOZ_COUNTED_DTOR_VIRTUAL(MediaTrackGraph)
+
+ // Intended only for assertions, either on graph thread or not running (in
+ // which case we must be on the main thread).
+ virtual bool OnGraphThreadOrNotRunning() const = 0;
+ virtual bool OnGraphThread() const = 0;
+
+ // Intended only for internal assertions. Main thread only.
+ virtual bool Destroyed() const = 0;
+
+ /**
+ * Sample rate at which this graph runs. For real time graphs, this is
+ * the rate of the audio mixer. For offline graphs, this is the rate specified
+ * at construction.
+ */
+ const TrackRate mSampleRate;
+ /**
+ * Device to use for audio output through an AudioCallbackDriver.
+ * This is the device specified when creating the graph.
+ */
+ const CubebUtils::AudioDeviceID mPrimaryOutputDeviceID;
+};
+
+inline void MediaTrack::AssertOnGraphThread() const {
+ Graph()->AssertOnGraphThread();
+}
+inline void MediaTrack::AssertOnGraphThreadOrNotRunning() const {
+ Graph()->AssertOnGraphThreadOrNotRunning();
+}
+
+/**
+ * This represents a message run on the graph thread to modify track or graph
+ * state. These are passed from main thread to graph thread by
+ * QueueControlMessageWithNoShutdown() or QueueControlOrShutdownMessage()
+ * through AppendMessage(), or scheduled on the graph thread with
+ * RunAfterProcessing().
+ */
+class MediaTrack::ControlMessageInterface {
+ public:
+ MOZ_COUNTED_DEFAULT_CTOR(ControlMessageInterface)
+ // All these run on the graph thread unless the graph has been forced to
+ // shut down.
+ MOZ_COUNTED_DTOR_VIRTUAL(ControlMessageInterface)
+ // Do the action of this message on the MediaTrackGraph thread. Any actions
+ // affecting graph processing should take effect at mProcessedTime.
+ // All track data for times < mProcessedTime has already been
+ // computed.
+ virtual void Run() = 0;
+ // RunDuringShutdown() is only relevant to messages generated on the main
+ // thread by QueueControlOrShutdownMessage() or 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() {}
+};
+
+template <typename Function>
+class MediaTrack::ControlMessageWithNoShutdown
+ : public ControlMessageInterface {
+ public:
+ explicit ControlMessageWithNoShutdown(Function&& aFunction)
+ : mFunction(std::forward<Function>(aFunction)) {}
+
+ void Run() override {
+ static_assert(std::is_void_v<decltype(mFunction())>,
+ "The lambda must return void!");
+ mFunction();
+ }
+
+ private:
+ using StoredFunction = std::decay_t<Function>;
+ StoredFunction mFunction;
+};
+
+template <typename Function>
+class MediaTrack::ControlOrShutdownMessage : public ControlMessageInterface {
+ public:
+ explicit ControlOrShutdownMessage(Function&& aFunction)
+ : mFunction(std::forward<Function>(aFunction)) {}
+
+ void Run() override {
+ static_assert(std::is_void_v<decltype(mFunction(IsInShutdown()))>,
+ "The lambda must return void!");
+ mFunction(IsInShutdown::No);
+ }
+ void RunDuringShutdown() override { mFunction(IsInShutdown::Yes); }
+
+ private:
+ // The same lambda is used whether or not in shutdown so that captured
+ // variables are available in both cases.
+ using StoredFunction = std::decay_t<Function>;
+ StoredFunction mFunction;
+};
+
+} // namespace mozilla
+
+#endif /* MOZILLA_MEDIATRACKGRAPH_H_ */