Bug 848954 - Part 4 - Factor behavior for drivers that manage their thread. r=roc

content/media/GraphDriver.cpp

@@ -58,19 +58,16 @@ DriverHolder::Switch(GraphDriver* aDriver)
   mDriver = aDriver;
 }
 
-SystemClockDriver::SystemClockDriver(MediaStreamGraphImpl* aGraphImpl)
+ThreadedDriver::ThreadedDriver(MediaStreamGraphImpl* aGraphImpl)
-  : GraphDriver(aGraphImpl),
+  : GraphDriver(aGraphImpl)
-    mInitialTimeStamp(TimeStamp::Now()),
+{ }
-    mLastTimeStamp(TimeStamp::Now()),
-    mCurrentTimeStamp(TimeStamp::Now())
-{}
 
-SystemClockDriver::~SystemClockDriver()
+ThreadedDriver::~ThreadedDriver()
 { }
 
 class MediaStreamGraphInitThreadRunnable : public nsRunnable {
 public:
-  explicit MediaStreamGraphInitThreadRunnable(GraphDriver* aDriver)
+  explicit MediaStreamGraphInitThreadRunnable(ThreadedDriver* aDriver)
     : mDriver(aDriver)
   {
   }
@@ -82,24 +79,24 @@ public:
     return NS_OK;
   }
 private:
-  GraphDriver* mDriver;
+  ThreadedDriver* mDriver;
 };
 
 void
-SystemClockDriver::Start()
+ThreadedDriver::Start()
 {
   nsCOMPtr<nsIRunnable> event = new MediaStreamGraphInitThreadRunnable(this);
   NS_NewNamedThread("MediaStreamGrph", getter_AddRefs(mThread), event);
 }
 
 void
-SystemClockDriver::Dispatch(nsIRunnable* aEvent)
+ThreadedDriver::Dispatch(nsIRunnable* aEvent)
 {
   mThread->Dispatch(aEvent, NS_DISPATCH_NORMAL);
 }
 
 void
-SystemClockDriver::Stop()
+ThreadedDriver::Stop()
 {
   NS_ASSERTION(NS_IsMainThread(), "Must be called on main thread");
   // mGraph's thread is not running so it's OK to do whatever here
@@ -111,8 +108,18 @@ SystemClockDriver::Stop()
   }
 }
 
+SystemClockDriver::SystemClockDriver(MediaStreamGraphImpl* aGraphImpl)
+  : ThreadedDriver(aGraphImpl),
+    mInitialTimeStamp(TimeStamp::Now()),
+    mLastTimeStamp(TimeStamp::Now()),
+    mCurrentTimeStamp(TimeStamp::Now())
+{}
+
+SystemClockDriver::~SystemClockDriver()
+{ }
+
 void
-SystemClockDriver::RunThread()
+ThreadedDriver::RunThread()
 {
   AutoProfilerUnregisterThread autoUnregister;
   nsTArray<MessageBlock> messageQueue;
@@ -216,7 +223,7 @@ SystemClockDriver::WakeUp()
 }
 
 OfflineClockDriver::OfflineClockDriver(MediaStreamGraphImpl* aGraphImpl, GraphTime aSlice)
-  : GraphDriver(aGraphImpl),
+  : ThreadedDriver(aGraphImpl),
     mSlice(aSlice)
 {
 
@@ -225,63 +232,6 @@ OfflineClockDriver::OfflineClockDriver(MediaStreamGraphImpl* aGraphImpl, GraphTi
 OfflineClockDriver::~OfflineClockDriver()
 { }
 
-void
-OfflineClockDriver::Start()
-{
-  nsCOMPtr<nsIRunnable> event = new MediaStreamGraphInitThreadRunnable(this);
-  NS_NewNamedThread("MediaStreamGrph", getter_AddRefs(mThread), event);
-}
-
-void
-OfflineClockDriver::Stop()
-{
-  NS_ASSERTION(NS_IsMainThread(), "Must be called on main thread");
-  // mGraph's thread is not running so it's OK to do whatever here
-  STREAM_LOG(PR_LOG_DEBUG, ("Stopping threads for MediaStreamGraph %p", this));
-
-  if (mThread) {
-    mThread->Shutdown();
-    mThread = nullptr;
-  }
-}
-
-void
-OfflineClockDriver::Dispatch(nsIRunnable* aEvent)
-{
-  mThread->Dispatch(aEvent, NS_DISPATCH_NORMAL);
-}
-
-void
-OfflineClockDriver::RunThread()
-{
-  AutoProfilerUnregisterThread autoUnregister;
-  nsTArray<MessageBlock> messageQueue;
-  {
-    MonitorAutoLock lock(mMonitor);
-    messageQueue.SwapElements(mGraphImpl->MessageQueue());
-  }
-  NS_ASSERTION(!messageQueue.IsEmpty(),
-               "Shouldn't have started a graph with empty message queue!");
-
-  bool stillProcessing = true;
-
-  while(stillProcessing) {
-    GraphTime prevCurrentTime, nextCurrentTime;
-    GetIntervalForIteration(prevCurrentTime, nextCurrentTime);
-
-    GraphTime nextStateComputedTime =
-      mGraphImpl->RoundUpToNextAudioBlock(
-          IterationEnd() + mGraphImpl->MillisecondsToMediaTime(AUDIO_TARGET_MS));
-
-
-    stillProcessing = mGraphImpl->OneIteration(prevCurrentTime,
-                                               nextCurrentTime,
-                                               StateComputedTime(),
-                                               nextStateComputedTime,
-                                               messageQueue);
-  }
-}
-
 void
 OfflineClockDriver::GetIntervalForIteration(GraphTime& aFrom, GraphTime& aTo)
 {

content/media/GraphDriver.h

@@ -9,7 +9,7 @@
 namespace mozilla {
 
 /**
- * We make the initial IterationEnd() nonzero so that zero times can have
+ * We make the initial graph time nonzero so that zero times can have
  * special meaning if necessary.
  */
 static const int32_t INITIAL_CURRENT_TIME = 1;
@@ -62,8 +62,13 @@ public:
   /* Dispatch an event to the graph's thread. */
   virtual void Dispatch(nsIRunnable* aEvent) = 0;
 
+  /**
+   * If we are running a real time graph, get the current time stamp to schedule
+   * video frames. This has to be reimplemented by real time drivers.
+   */
   virtual TimeStamp GetCurrentTimeStamp() {
     MOZ_ASSERT(false, "This clock does not support getting the current time stamp.");
+    return TimeStamp();
   }
 
   bool IsWaiting() {
@@ -87,6 +92,11 @@ public:
     return mStateComputedTime;
   }
 
+  /**
+   * Whenever the graph has computed the time until it has all state
+   * (mStateComputedState), it calls this to indicate the new time until which
+   * we have computed state.
+   */
   void UpdateStateComputedTime(GraphTime aStateComputedTime) {
     MOZ_ASSERT(aStateComputedTime > mIterationEnd);
 
@@ -194,19 +204,31 @@ protected:
   GraphTime mLastSwitchOffset;
 };
 
+/**
+ * This class is a driver that manages its own thread.
+ */
+class ThreadedDriver : public GraphDriver
+{
+public:
+  ThreadedDriver(MediaStreamGraphImpl* aGraphImpl);
+  virtual ~ThreadedDriver();
+  virtual void Start() MOZ_OVERRIDE;
+  virtual void Stop() MOZ_OVERRIDE;
+  virtual void Dispatch(nsIRunnable* aEvent) MOZ_OVERRIDE;
+  void RunThread();
+private:
+  nsCOMPtr<nsIThread> mThread;
+};
+
 /**
  * A SystemClockDriver drives a MediaStreamGraph using a system clock, and waits
  * using a monitor, between each iteration.
  */
-class SystemClockDriver : public GraphDriver
+class SystemClockDriver : public ThreadedDriver
 {
 public:
   SystemClockDriver(MediaStreamGraphImpl* aGraphImpl);
   virtual ~SystemClockDriver();
-  virtual void Start() MOZ_OVERRIDE;
-  virtual void Stop() MOZ_OVERRIDE;
-  virtual void Dispatch(nsIRunnable* aEvent) MOZ_OVERRIDE;
-  virtual void RunThread() MOZ_OVERRIDE;
   virtual void GetIntervalForIteration(GraphTime& aFrom,
                                        GraphTime& aTo) MOZ_OVERRIDE;
   virtual GraphTime GetCurrentTime() MOZ_OVERRIDE;
@@ -219,22 +241,17 @@ private:
   TimeStamp mInitialTimeStamp;
   TimeStamp mLastTimeStamp;
   TimeStamp mCurrentTimeStamp;
-  nsCOMPtr<nsIThread> mThread;
 };
 
 /**
  * An OfflineClockDriver runs the graph as fast as possible, without waiting
  * between iteration.
  */
-class OfflineClockDriver : public GraphDriver
+class OfflineClockDriver : public ThreadedDriver
 {
 public:
   OfflineClockDriver(MediaStreamGraphImpl* aGraphImpl, GraphTime aSlice);
   virtual ~OfflineClockDriver();
-  virtual void Start() MOZ_OVERRIDE;
-  virtual void Stop() MOZ_OVERRIDE;
-  virtual void Dispatch(nsIRunnable* aEvent) MOZ_OVERRIDE;
-  virtual void RunThread() MOZ_OVERRIDE;
   virtual void GetIntervalForIteration(GraphTime& aFrom,
                                        GraphTime& aTo) MOZ_OVERRIDE;
   virtual GraphTime GetCurrentTime() MOZ_OVERRIDE;
@@ -244,7 +261,6 @@ public:
 private:
   // Time, in GraphTime, for each iteration
   GraphTime mSlice;
-  nsCOMPtr<nsIThread> mThread;
 };
 
 }

content/media/MediaStreamGraph.cpp

@@ -2657,7 +2657,7 @@ ProcessedMediaStream::DestroyImpl()
 }
 
 MediaStreamGraphImpl::MediaStreamGraphImpl(bool aRealtime, TrackRate aSampleRate)
-  : mDriverHolder(this)
+  : mDriverHolder(MOZ_THIS_IN_INITIALIZER_LIST())
   , mProcessingGraphUpdateIndex(0)
   , mPortCount(0)
   , mLifecycleState(LIFECYCLE_THREAD_NOT_STARTED)
@@ -2798,7 +2798,7 @@ MediaStreamGraphImpl::CollectReports(nsIHandleReportCallback* aHandleReport,
     mNeedsMemoryReport = true;
 
     // Wake up the MSG thread.
-    CurrentDriver()->EnsureImmediateWakeUpLocked();
+    CurrentDriver()->WakeUp();
 
     if (mLifecycleState >= LIFECYCLE_WAITING_FOR_THREAD_SHUTDOWN) {
       // Shutting down, nothing to report.