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Bug 804387. Part 4: Move MediaStreamGraphImpl to its own header file. r=jesup

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--HG--
rename : content/media/MediaStreamGraph.cpp => content/media/MediaStreamGraphImpl.h
This commit is contained in:
Robert O'Callahan 2013-02-04 23:04:25 +13:00
parent 5350b6e757
commit be9e936592
2 changed files with 499 additions and 481 deletions
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482
content/media/MediaStreamGraph.cpp
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@ -3,10 +3,8 @@
* 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/. */
#include "MediaStreamGraph.h"
#include "MediaStreamGraphImpl.h"
#include "mozilla/Monitor.h"
#include "mozilla/TimeStamp.h"
#include "AudioSegment.h"
#include "VideoSegment.h"
#include "nsContentUtils.h"
@ -30,486 +28,8 @@ namespace mozilla {
#ifdef PR_LOGGING
PRLogModuleInfo* gMediaStreamGraphLog;
#define LOG(type, msg) PR_LOG(gMediaStreamGraphLog, type, msg)
#else
#define LOG(type, msg)
#endif
namespace {
/**
* Assume we can run an iteration of the MediaStreamGraph loop in this much time
* or less.
* We try to run the control loop at this rate.
*/
const int MEDIA_GRAPH_TARGET_PERIOD_MS = 10;
/**
* Assume that we might miss our scheduled wakeup of the MediaStreamGraph by
* this much.
*/
const int SCHEDULE_SAFETY_MARGIN_MS = 10;
/**
* Try have this much audio buffered in streams and queued to the hardware.
* The maximum delay to the end of the next control loop
* is 2*MEDIA_GRAPH_TARGET_PERIOD_MS + SCHEDULE_SAFETY_MARGIN_MS.
* There is no point in buffering more audio than this in a stream at any
* given time (until we add processing).
* This is not optimal yet.
*/
const int AUDIO_TARGET_MS = 2*MEDIA_GRAPH_TARGET_PERIOD_MS +
SCHEDULE_SAFETY_MARGIN_MS;
/**
* Try have this much video buffered. Video frames are set
* near the end of the iteration of the control loop. The maximum delay
* to the setting of the next video frame is 2*MEDIA_GRAPH_TARGET_PERIOD_MS +
* SCHEDULE_SAFETY_MARGIN_MS. This is not optimal yet.
*/
const int VIDEO_TARGET_MS = 2*MEDIA_GRAPH_TARGET_PERIOD_MS +
SCHEDULE_SAFETY_MARGIN_MS;
/**
* A per-stream update message passed from the media graph thread to the
* main thread.
*/
struct StreamUpdate {
int64_t mGraphUpdateIndex;
nsRefPtr<MediaStream> mStream;
StreamTime mNextMainThreadCurrentTime;
bool mNextMainThreadFinished;
};
/**
* This represents a message passed from the main thread to the graph thread.
* A ControlMessage always references a particular affected stream.
*/
class ControlMessage {
public:
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 mStateComputedTime.
// All stream data for times < mStateComputedTime has already been
// computed.
virtual void Run() = 0;
// When we're shutting down the application, most messages are ignored but
// some cleanup messages should still be processed (on the main thread).
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;
};
}
/**
* 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.
*
* Currently we only have one per process.
*/
class MediaStreamGraphImpl : public MediaStreamGraph {
public:
MediaStreamGraphImpl();
~MediaStreamGraphImpl()
{
NS_ASSERTION(IsEmpty(),
"All streams should have been destroyed by messages from the main thread");
LOG(PR_LOG_DEBUG, ("MediaStreamGraph %p destroyed", this));
}
// 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.
*/
void RunInStableState();
/**
* 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(ControlMessage* aMessage);
/**
* 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();
/**
* Shutdown() this MediaStreamGraph's threads and return when they've shut down.
*/
void ShutdownThreads();
// The following methods run on the graph thread (or possibly the main thread if
// mLifecycleState > LIFECYCLE_RUNNING)
/**
* Runs main control loop on the graph thread. Normally a single invocation
* of this runs for the entire lifetime of the graph thread.
*/
void RunThread();
/**
* Call this to indicate that another iteration of the control loop is
* required on its regular schedule. The monitor must not be held.
*/
void EnsureNextIteration();
/**
* As above, but with the monitor already held.
*/
void EnsureNextIterationLocked(MonitorAutoLock& aLock);
/**
* Call this to indicate that another iteration of the control loop is
* required immediately. The monitor must already be held.
*/
void EnsureImmediateWakeUpLocked(MonitorAutoLock& aLock);
/**
* 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();
// The following methods are the various stages of RunThread processing.
/**
* Compute a new current time for the graph and advance all on-graph-thread
* state to the new current time.
*/
void UpdateCurrentTime();
/**
* Update the consumption state of aStream to reflect whether its data
* is needed or not.
*/
void UpdateConsumptionState(SourceMediaStream* aStream);
/**
* Extract any state updates pending in aStream, and apply them.
*/
void ExtractPendingInput(SourceMediaStream* aStream,
GraphTime aDesiredUpToTime,
bool* aEnsureNextIteration);
/**
* Update "have enough data" flags in aStream.
*/
void UpdateBufferSufficiencyState(SourceMediaStream* aStream);
/*
* If aStream hasn't already been ordered, push it onto aStack and order
* its children.
*/
void UpdateStreamOrderForStream(nsTArray<MediaStream*>* aStack,
already_AddRefed<MediaStream> aStream);
/**
* Mark aStream and all its inputs (recursively) as consumed.
*/
static void MarkConsumed(MediaStream* aStream);
/**
* 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();
/**
* Compute the blocking states of streams from mStateComputedTime
* until the desired future time aEndBlockingDecisions.
* Updates mStateComputedTime and sets MediaStream::mBlocked
* for all streams.
*/
void RecomputeBlocking(GraphTime aEndBlockingDecisions);
// The following methods are used to help RecomputeBlocking.
/**
* If aStream isn't already in aStreams, add it and recursively call
* AddBlockingRelatedStreamsToSet on all the streams whose blocking
* status could depend on or affect the state of aStream.
*/
void AddBlockingRelatedStreamsToSet(nsTArray<MediaStream*>* aStreams,
MediaStream* aStream);
/**
* Mark a stream blocked at time aTime. If this results in decisions that need
* to be revisited at some point in the future, *aEnd will be reduced to the
* first time in the future to recompute those decisions.
*/
void MarkStreamBlocking(MediaStream* aStream);
/**
* Recompute blocking for the streams in aStreams for the interval starting at aTime.
* If this results in decisions that need to be revisited at some point
* in the future, *aEnd will be reduced to the first time in the future to
* recompute those decisions.
*/
void RecomputeBlockingAt(const nsTArray<MediaStream*>& aStreams,
GraphTime aTime, GraphTime aEndBlockingDecisions,
GraphTime* aEnd);
/**
* Returns true if aStream will underrun at aTime for its own playback.
* aEndBlockingDecisions is when we plan to stop making blocking decisions.
* *aEnd will be reduced to the first time in the future to recompute these
* decisions.
*/
bool WillUnderrun(MediaStream* aStream, GraphTime aTime,
GraphTime aEndBlockingDecisions, GraphTime* aEnd);
/**
* 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 GraphTimeToStreamTime(MediaStream* aStream, GraphTime aTime);
enum {
INCLUDE_TRAILING_BLOCKED_INTERVAL = 0x01
};
/**
* Given a stream time aTime, convert it to a graph time taking into
* account the time during which aStream is scheduled to be blocked.
* aTime must be <= mStateComputedTime since blocking decisions
* are only known up to that point.
* If aTime is exactly at the start of a blocked interval, then the blocked
* interval is included in the time returned if and only if
* aFlags includes INCLUDE_TRAILING_BLOCKED_INTERVAL.
*/
GraphTime StreamTimeToGraphTime(MediaStream* aStream, StreamTime aTime,
uint32_t aFlags = 0);
/**
* Get the current audio position of the stream's audio output.
*/
GraphTime GetAudioPosition(MediaStream* aStream);
/**
* 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(GraphTime aAudioOutputStartTime,
MediaStream* aStream);
/**
* Queue audio (mix of stream audio and silence for blocked intervals)
* to the audio output stream.
*/
void PlayAudio(MediaStream* aStream, GraphTime aFrom, GraphTime aTo);
/**
* Set the correct current video frame for stream aStream.
*/
void PlayVideo(MediaStream* aStream);
/**
* No more data will be forthcoming for aStream. The stream will end
* at the current buffer end point. The StreamBuffer's tracks must be
* explicitly set to finished by the caller.
*/
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() { return mStreams.IsEmpty() && mPortCount == 0; }
// For use by control messages
/**
* Identify which graph update index we are currently processing.
*/
int64_t GetProcessingGraphUpdateIndex() { return mProcessingGraphUpdateIndex; }
/**
* Add aStream to the graph and initializes its graph-specific state.
*/
void AddStream(MediaStream* aStream);
/**
* Remove aStream from the graph. Ensures that pending messages about the
* stream back to the main thread are flushed.
*/
void RemoveStream(MediaStream* aStream);
/**
* Remove aPort from the graph and release it.
*/
void DestroyPort(MediaInputPort* aPort);
// Data members
/**
* Media graph thread.
* Readonly after initialization on the main thread.
*/
nsCOMPtr<nsIThread> mThread;
// 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.
nsTArray<nsRefPtr<MediaStream> > mStreams;
/**
* The current graph time for the current iteration of the RunThread control
* loop.
*/
GraphTime mCurrentTime;
/**
* Blocking decisions and 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. Always >= mCurrentTime.
*/
GraphTime mStateComputedTime;
/**
* This is only used for logging.
*/
TimeStamp mInitialTimeStamp;
/**
* The real timestamp of the latest run of UpdateCurrentTime.
*/
TimeStamp mCurrentTimeStamp;
/**
* Which update batch we are currently processing.
*/
int64_t mProcessingGraphUpdateIndex;
/**
* Number of active MediaInputPorts
*/
int32_t mPortCount;
// 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;
struct MessageBlock {
int64_t mGraphUpdateIndex;
nsTArray<nsAutoPtr<ControlMessage> > mMessages;
};
/**
* A list of batches of messages to process. Each batch is processed
* as an atomic unit.
*/
nsTArray<MessageBlock> mMessageQueue;
/**
* 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. 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.
*/
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 since normally
// we'd only shut down a graph when it has no streams.
LIFECYCLE_WAITING_FOR_STREAM_DESTRUCTION
};
LifecycleState mLifecycleState;
/**
* This enum specifies the wait state of the graph thread.
*/
enum WaitState {
// RunThread() is running normally
WAITSTATE_RUNNING,
// RunThread() is paused waiting for its next iteration, which will
// happen soon
WAITSTATE_WAITING_FOR_NEXT_ITERATION,
// RunThread() is paused indefinitely waiting for something to change
WAITSTATE_WAITING_INDEFINITELY,
// Something has signaled RunThread() to wake up immediately,
// but it hasn't done so yet
WAITSTATE_WAKING_UP
};
WaitState mWaitState;
/**
* True when another iteration of the control loop is required.
*/
bool mNeedAnotherIteration;
/**
* True when we need to do a forced shutdown during application shutdown.
*/
bool mForceShutDown;
/**
* 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<nsAutoPtr<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;
};
/**
* The singleton graph instance.
*/

498
content/media/MediaStreamGraphImpl.h Normal file
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@ -0,0 +1,498 @@
/* -*- 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 "mozilla/Monitor.h"
#include "mozilla/TimeStamp.h"
#include "nsIThread.h"
#include "nsIRunnable.h"
namespace mozilla {
#ifdef PR_LOGGING
extern PRLogModuleInfo* gMediaStreamGraphLog;
#define LOG(type, msg) PR_LOG(gMediaStreamGraphLog, type, msg)
#else
#define LOG(type, msg)
#endif
/**
* Assume we can run an iteration of the MediaStreamGraph loop in this much time
* or less.
* We try to run the control loop at this rate.
*/
static const int MEDIA_GRAPH_TARGET_PERIOD_MS = 10;
/**
* Assume that we might miss our scheduled wakeup of the MediaStreamGraph by
* this much.
*/
static const int SCHEDULE_SAFETY_MARGIN_MS = 10;
/**
* Try have this much audio buffered in streams and queued to the hardware.
* The maximum delay to the end of the next control loop
* is 2*MEDIA_GRAPH_TARGET_PERIOD_MS + SCHEDULE_SAFETY_MARGIN_MS.
* There is no point in buffering more audio than this in a stream at any
* given time (until we add processing).
* This is not optimal yet.
*/
static const int AUDIO_TARGET_MS = 2*MEDIA_GRAPH_TARGET_PERIOD_MS +
SCHEDULE_SAFETY_MARGIN_MS;
/**
* Try have this much video buffered. Video frames are set
* near the end of the iteration of the control loop. The maximum delay
* to the setting of the next video frame is 2*MEDIA_GRAPH_TARGET_PERIOD_MS +
* SCHEDULE_SAFETY_MARGIN_MS. This is not optimal yet.
*/
static const int VIDEO_TARGET_MS = 2*MEDIA_GRAPH_TARGET_PERIOD_MS +
SCHEDULE_SAFETY_MARGIN_MS;
/**
* A per-stream update message passed from the media graph thread to the
* main thread.
*/
struct StreamUpdate {
int64_t mGraphUpdateIndex;
nsRefPtr<MediaStream> mStream;
StreamTime mNextMainThreadCurrentTime;
bool mNextMainThreadFinished;
};
/**
* This represents a message passed from the main thread to the graph thread.
* A ControlMessage always references a particular affected stream.
*/
class ControlMessage {
public:
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 mStateComputedTime.
// All stream data for times < mStateComputedTime has already been
// computed.
virtual void Run() = 0;
// When we're shutting down the application, most messages are ignored but
// some cleanup messages should still be processed (on the main thread).
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;
};
/**
* 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.
*
* Currently we only have one per process.
*/
class MediaStreamGraphImpl : public MediaStreamGraph {
public:
MediaStreamGraphImpl();
~MediaStreamGraphImpl()
{
NS_ASSERTION(IsEmpty(),
"All streams should have been destroyed by messages from the main thread");
LOG(PR_LOG_DEBUG, ("MediaStreamGraph %p destroyed", this));
}
// 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.
*/
void RunInStableState();
/**
* 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(ControlMessage* aMessage);
/**
* 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();
/**
* Shutdown() this MediaStreamGraph's threads and return when they've shut down.
*/
void ShutdownThreads();
// The following methods run on the graph thread (or possibly the main thread if
// mLifecycleState > LIFECYCLE_RUNNING)
/**
* Runs main control loop on the graph thread. Normally a single invocation
* of this runs for the entire lifetime of the graph thread.
*/
void RunThread();
/**
* Call this to indicate that another iteration of the control loop is
* required on its regular schedule. The monitor must not be held.
*/
void EnsureNextIteration();
/**
* As above, but with the monitor already held.
*/
void EnsureNextIterationLocked(MonitorAutoLock& aLock);
/**
* Call this to indicate that another iteration of the control loop is
* required immediately. The monitor must already be held.
*/
void EnsureImmediateWakeUpLocked(MonitorAutoLock& aLock);
/**
* 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();
// The following methods are the various stages of RunThread processing.
/**
* Compute a new current time for the graph and advance all on-graph-thread
* state to the new current time.
*/
void UpdateCurrentTime();
/**
* Update the consumption state of aStream to reflect whether its data
* is needed or not.
*/
void UpdateConsumptionState(SourceMediaStream* aStream);
/**
* Extract any state updates pending in aStream, and apply them.
*/
void ExtractPendingInput(SourceMediaStream* aStream,
GraphTime aDesiredUpToTime,
bool* aEnsureNextIteration);
/**
* Update "have enough data" flags in aStream.
*/
void UpdateBufferSufficiencyState(SourceMediaStream* aStream);
/*
* If aStream hasn't already been ordered, push it onto aStack and order
* its children.
*/
void UpdateStreamOrderForStream(nsTArray<MediaStream*>* aStack,
already_AddRefed<MediaStream> aStream);
/**
* Mark aStream and all its inputs (recursively) as consumed.
*/
static void MarkConsumed(MediaStream* aStream);
/**
* 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();
/**
* Compute the blocking states of streams from mStateComputedTime
* until the desired future time aEndBlockingDecisions.
* Updates mStateComputedTime and sets MediaStream::mBlocked
* for all streams.
*/
void RecomputeBlocking(GraphTime aEndBlockingDecisions);
// The following methods are used to help RecomputeBlocking.
/**
* If aStream isn't already in aStreams, add it and recursively call
* AddBlockingRelatedStreamsToSet on all the streams whose blocking
* status could depend on or affect the state of aStream.
*/
void AddBlockingRelatedStreamsToSet(nsTArray<MediaStream*>* aStreams,
MediaStream* aStream);
/**
* Mark a stream blocked at time aTime. If this results in decisions that need
* to be revisited at some point in the future, *aEnd will be reduced to the
* first time in the future to recompute those decisions.
*/
void MarkStreamBlocking(MediaStream* aStream);
/**
* Recompute blocking for the streams in aStreams for the interval starting at aTime.
* If this results in decisions that need to be revisited at some point
* in the future, *aEnd will be reduced to the first time in the future to
* recompute those decisions.
*/
void RecomputeBlockingAt(const nsTArray<MediaStream*>& aStreams,
GraphTime aTime, GraphTime aEndBlockingDecisions,
GraphTime* aEnd);
/**
* Returns true if aStream will underrun at aTime for its own playback.
* aEndBlockingDecisions is when we plan to stop making blocking decisions.
* *aEnd will be reduced to the first time in the future to recompute these
* decisions.
*/
bool WillUnderrun(MediaStream* aStream, GraphTime aTime,
GraphTime aEndBlockingDecisions, GraphTime* aEnd);
/**
* 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 GraphTimeToStreamTime(MediaStream* aStream, GraphTime aTime);
enum {
INCLUDE_TRAILING_BLOCKED_INTERVAL = 0x01
};
/**
* Given a stream time aTime, convert it to a graph time taking into
* account the time during which aStream is scheduled to be blocked.
* aTime must be <= mStateComputedTime since blocking decisions
* are only known up to that point.
* If aTime is exactly at the start of a blocked interval, then the blocked
* interval is included in the time returned if and only if
* aFlags includes INCLUDE_TRAILING_BLOCKED_INTERVAL.
*/
GraphTime StreamTimeToGraphTime(MediaStream* aStream, StreamTime aTime,
uint32_t aFlags = 0);
/**
* Get the current audio position of the stream's audio output.
*/
GraphTime GetAudioPosition(MediaStream* aStream);
/**
* 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(GraphTime aAudioOutputStartTime,
MediaStream* aStream);
/**
* Queue audio (mix of stream audio and silence for blocked intervals)
* to the audio output stream.
*/
void PlayAudio(MediaStream* aStream, GraphTime aFrom, GraphTime aTo);
/**
* Set the correct current video frame for stream aStream.
*/
void PlayVideo(MediaStream* aStream);
/**
* No more data will be forthcoming for aStream. The stream will end
* at the current buffer end point. The StreamBuffer's tracks must be
* explicitly set to finished by the caller.
*/
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() { return mStreams.IsEmpty() && mPortCount == 0; }
// For use by control messages
/**
* Identify which graph update index we are currently processing.
*/
int64_t GetProcessingGraphUpdateIndex() { return mProcessingGraphUpdateIndex; }
/**
* Add aStream to the graph and initializes its graph-specific state.
*/
void AddStream(MediaStream* aStream);
/**
* Remove aStream from the graph. Ensures that pending messages about the
* stream back to the main thread are flushed.
*/
void RemoveStream(MediaStream* aStream);
/**
* Remove aPort from the graph and release it.
*/
void DestroyPort(MediaInputPort* aPort);
// Data members
/**
* Media graph thread.
* Readonly after initialization on the main thread.
*/
nsCOMPtr<nsIThread> mThread;
// 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.
nsTArray<nsRefPtr<MediaStream> > mStreams;
/**
* The current graph time for the current iteration of the RunThread control
* loop.
*/
GraphTime mCurrentTime;
/**
* Blocking decisions and 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. Always >= mCurrentTime.
*/
GraphTime mStateComputedTime;
/**
* This is only used for logging.
*/
TimeStamp mInitialTimeStamp;
/**
* The real timestamp of the latest run of UpdateCurrentTime.
*/
TimeStamp mCurrentTimeStamp;
/**
* Which update batch we are currently processing.
*/
int64_t mProcessingGraphUpdateIndex;
/**
* Number of active MediaInputPorts
*/
int32_t mPortCount;
// 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;
struct MessageBlock {
int64_t mGraphUpdateIndex;
nsTArray<nsAutoPtr<ControlMessage> > mMessages;
};
/**
* A list of batches of messages to process. Each batch is processed
* as an atomic unit.
*/
nsTArray<MessageBlock> mMessageQueue;
/**
* 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. 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.
*/
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 since normally
// we'd only shut down a graph when it has no streams.
LIFECYCLE_WAITING_FOR_STREAM_DESTRUCTION
};
LifecycleState mLifecycleState;
/**
* This enum specifies the wait state of the graph thread.
*/
enum WaitState {
// RunThread() is running normally
WAITSTATE_RUNNING,
// RunThread() is paused waiting for its next iteration, which will
// happen soon
WAITSTATE_WAITING_FOR_NEXT_ITERATION,
// RunThread() is paused indefinitely waiting for something to change
WAITSTATE_WAITING_INDEFINITELY,
// Something has signaled RunThread() to wake up immediately,
// but it hasn't done so yet
WAITSTATE_WAKING_UP
};
WaitState mWaitState;
/**
* True when another iteration of the control loop is required.
*/
bool mNeedAnotherIteration;
/**
* True when we need to do a forced shutdown during application shutdown.
*/
bool mForceShutDown;
/**
* 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<nsAutoPtr<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;
};
}
#endif /* MEDIASTREAMGRAPHIMPL_H_ */