Bug 951008 - Media Recorder - fire onstart event when encoder start to generate encoded data. r=roc, sr=khuey.

content/media/MediaRecorder.cpp

@@ -100,7 +100,7 @@ class MediaRecorder::Session: public nsIObserver
       if (!recorder) {
         return NS_OK;
       }
-      recorder->SetMimeType(mSession->mMimeType);
+
       if (mSession->IsEncoderError()) {
         recorder->NotifyError(NS_ERROR_UNEXPECTED);
       }
@@ -116,6 +116,34 @@ class MediaRecorder::Session: public nsIObserver
     nsRefPtr<Session> mSession;
   };
 
+  // Fire start event and set mimeType, run in main thread task.
+  class DispatchStartEventRunnable : public nsRunnable
+  {
+  public:
+    DispatchStartEventRunnable(Session* aSession, const nsAString & aEventName)
+      : mSession(aSession)
+      , mEventName(aEventName)
+    { }
+
+    NS_IMETHODIMP Run()
+    {
+      LOG(PR_LOG_DEBUG, ("Session.DispatchStartEventRunnable s=(%p)", mSession.get()));
+      MOZ_ASSERT(NS_IsMainThread());
+
+      NS_ENSURE_TRUE(mSession->mRecorder, NS_OK);
+      nsRefPtr<MediaRecorder> recorder = mSession->mRecorder;
+
+      recorder->SetMimeType(mSession->mMimeType);
+      recorder->DispatchSimpleEvent(mEventName);
+
+      return NS_OK;
+    }
+
+  private:
+    nsRefPtr<Session> mSession;
+    nsString mEventName;
+  };
+
   // Record thread task and it run in Media Encoder thread.
   // Fetch encoded Audio/Video data from MediaEncoder.
   class ExtractRunnable : public nsRunnable
@@ -228,7 +256,8 @@ public:
   Session(MediaRecorder* aRecorder, int32_t aTimeSlice)
     : mRecorder(aRecorder),
       mTimeSlice(aTimeSlice),
-      mStopIssued(false)
+      mStopIssued(false),
+      mCanRetrieveData(false)
   {
     MOZ_ASSERT(NS_IsMainThread());
 
@@ -312,7 +341,15 @@ private:
 
     // Append pulled data into cache buffer.
     for (uint32_t i = 0; i < encodedBuf.Length(); i++) {
-      mEncodedBufferCache->AppendBuffer(encodedBuf[i]);
+      if (!encodedBuf[i].IsEmpty()) {
+        mEncodedBufferCache->AppendBuffer(encodedBuf[i]);
+        // Fire the start event when encoded data is available.
+        if (!mCanRetrieveData) {
+          NS_DispatchToMainThread(
+            new DispatchStartEventRunnable(this, NS_LITERAL_STRING("start")));
+          mCanRetrieveData = true;
+        }
+      }
     }
 
     // Whether push encoded data back to onDataAvailable automatically or we
@@ -471,6 +508,8 @@ private:
   const int32_t mTimeSlice;
   // Indicate this session's stop has been called.
   bool mStopIssued;
+  // Indicate session has encoded data. This can be changed in recording thread.
+  bool mCanRetrieveData;
 };
 
 NS_IMPL_ISUPPORTS(MediaRecorder::Session, nsIObserver)
@@ -483,8 +522,7 @@ MediaRecorder::~MediaRecorder()
 
 MediaRecorder::MediaRecorder(DOMMediaStream& aStream, nsPIDOMWindow* aOwnerWindow)
   : DOMEventTargetHelper(aOwnerWindow),
-    mState(RecordingState::Inactive),
-    mMutex("Session.Data.Mutex")
+    mState(RecordingState::Inactive)
 {
   MOZ_ASSERT(aOwnerWindow);
   MOZ_ASSERT(aOwnerWindow->IsInnerWindow());
@@ -526,14 +564,12 @@ MediaRecorder::UnRegisterActivityObserver()
 void
 MediaRecorder::SetMimeType(const nsString &aMimeType)
 {
-  MutexAutoLock lock(mMutex);
   mMimeType = aMimeType;
 }
 
 void
 MediaRecorder::GetMimeType(nsString &aMimeType)
 {
-  MutexAutoLock lock(mMutex);
   aMimeType = mMimeType;
 }
 

content/media/MediaRecorder.h

@@ -84,6 +84,7 @@ public:
   // EventHandler
   IMPL_EVENT_HANDLER(dataavailable)
   IMPL_EVENT_HANDLER(error)
+  IMPL_EVENT_HANDLER(start)
   IMPL_EVENT_HANDLER(stop)
   IMPL_EVENT_HANDLER(warning)
 
@@ -112,8 +113,6 @@ protected:
   // Hold the sessions pointer and clean it when the DestroyRunnable for a
   // session is running.
   nsTArray<Session*> mSessions;
-  // Thread safe for mMimeType.
-  Mutex mMutex;
   // It specifies the container format as well as the audio and video capture formats.
   nsString mMimeType;
 

content/media/test/mochitest.ini

@@ -378,6 +378,7 @@ skip-if = buildapp == 'b2g' || toolkit == 'android' # mimetype check, bug 969289
 [test_mediarecorder_record_timeslice.html]
 [test_mediarecorder_reload_crash.html]
 [test_mediarecorder_unsupported_src.html]
+[test_mediarecorder_record_getdata_afterstart.html]
 [test_metadata.html]
 [test_mixed_principals.html]
 skip-if = true # bug 567954 and intermittent leaks

content/media/test/test_mediarecorder_record_getdata_afterstart.html

@@ -0,0 +1,79 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Bug 951008 Test MediaRecorder Record has start event</title>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+  <script type="text/javascript" src="manifest.js"></script>
+</head>
+<body>
+
+<script class="testbody" type="text/javascript">
+
+var manager = new MediaTestManager;
+
+function startTest(test, token) {
+
+  var element = document.createElement('audio');
+  var hasonstart = false;
+  var hasondataavailable = false;
+  var mMediaRecorder;
+
+  element.token = token;
+  manager.started(token);
+  element.src = test.name;
+  element.test = test;
+  element.stream = element.mozCaptureStream();
+
+  mMediaRecorder = new MediaRecorder(element.stream);
+  mMediaRecorder.onwarning = function() {
+    ok(false, 'onwarning unexpectedly fired');
+  };
+
+  mMediaRecorder.onerror = function() {
+    ok(false, 'onerror unexpectedly fired');
+  };
+
+  mMediaRecorder.onstart = function() {
+    info('onstart fired successfully');
+    hasonstart = true;
+    // On audio only case, we produce audio/ogg as mimeType.
+    is('audio/ogg', mMediaRecorder.mimeType, "check the record mimetype return " + mMediaRecorder.mimeType);
+    mMediaRecorder.requestData();
+  };
+
+  mMediaRecorder.onstop = function() {
+    info('onstop fired successfully');
+    ok (hasondataavailable, "should have ondataavailable before onstop");
+    is(mMediaRecorder.state, 'inactive', 'check recording status is inactive');
+    SimpleTest.finish();
+  };
+
+  mMediaRecorder.ondataavailable = function (e) {
+    info('ondataavailable fired successfully');
+    if (mMediaRecorder.state == 'recording') {
+      hasondataavailable = true;
+      ok(hasonstart, "should has onstart event first");
+      ok(e.data.size > 0, 'check blob has data');
+      mMediaRecorder.stop();
+    }
+  };
+
+  // Start recording once metadata are parsed.
+  element.onloadedmetadata = function() {
+    element.oncanplaythrough = null;
+    mMediaRecorder.start(0);
+    is(mMediaRecorder.state, 'recording', 'Media recorder should be recording');
+    is(mMediaRecorder.stream, element.stream,
+       'Media recorder stream = element stream at the start of recording');
+    };
+
+  element.play();
+}
+
+manager.runTests(gMediaRecorderTests, startTest);
+
+</script>
+</pre>
+</body>
+</html>

dom/webidl/MediaRecorder.webidl

@@ -25,6 +25,8 @@ interface MediaRecorder : EventTarget {
 
   attribute EventHandler onerror;
 
+  attribute EventHandler onstart;
+
   attribute EventHandler onstop;
 
   attribute EventHandler onwarning;