Bug 872430 - Timeout between when the media is paused and when the wakelock is released. r=jlebar

content/html/content/public/HTMLMediaElement.h

@@ -43,6 +43,8 @@ class MediaResource;
 class MediaDecoder;
 }
 
+class nsITimer;
+
 namespace mozilla {
 namespace dom {
 
@@ -533,6 +535,8 @@ protected:
     WakeLockBoolWrapper(bool val = false)
       : mValue(val), mCanPlay(true), mOuter(nullptr) {}
 
+    ~WakeLockBoolWrapper();
+
     void SetOuter(HTMLMediaElement* outer) { mOuter = outer; }
     void SetCanPlay(bool aCanPlay);
 
@@ -542,12 +546,15 @@ protected:
 
     bool operator !() const { return !mValue; }
 
+    static void TimerCallback(nsITimer* aTimer, void* aClosure);
+
   private:
     void UpdateWakeLock();
 
     bool mValue;
     bool mCanPlay;
     HTMLMediaElement* mOuter;
+    nsCOMPtr<nsITimer> mTimer;
   };
 
   /**

content/html/content/src/HTMLMediaElement.cpp

@@ -1987,6 +1987,8 @@ HTMLMediaElement::~HTMLMediaElement()
   if (mAudioStream) {
     mAudioStream->Shutdown();
   }
+
+  WakeLockRelease();
 }
 
 void
@@ -2106,7 +2108,8 @@ NS_IMETHODIMP HTMLMediaElement::Play()
 }
 
 HTMLMediaElement::WakeLockBoolWrapper&
-HTMLMediaElement::WakeLockBoolWrapper::operator=(bool val) {
+HTMLMediaElement::WakeLockBoolWrapper::operator=(bool val)
+{
   if (mValue == val) {
     return *this;
   }
@@ -2116,6 +2119,13 @@ HTMLMediaElement::WakeLockBoolWrapper::operator=(bool val) {
   return *this;
 }
 
+HTMLMediaElement::WakeLockBoolWrapper::~WakeLockBoolWrapper()
+{
+  if (mTimer) {
+    mTimer->Cancel();
+  }
+}
+
 void
 HTMLMediaElement::WakeLockBoolWrapper::SetCanPlay(bool aCanPlay)
 {
@@ -2133,12 +2143,30 @@ HTMLMediaElement::WakeLockBoolWrapper::UpdateWakeLock()
   bool playing = (!mValue && mCanPlay);
 
   if (playing) {
+    if (mTimer) {
+      mTimer->Cancel();
+      mTimer = nullptr;
+    }
     mOuter->WakeLockCreate();
-  } else {
-    mOuter->WakeLockRelease();
+  } else if (!mTimer) {
+    // Don't release the wake lock immediately; instead, release it after a
+    // grace period.
+    int timeout = Preferences::GetInt("media.wakelock_timeout", 2000);
+    mTimer = do_CreateInstance("@mozilla.org/timer;1");
+    mTimer->InitWithFuncCallback(TimerCallback, this, timeout,
+                                 nsITimer::TYPE_ONE_SHOT);
   }
 }
 
+void
+HTMLMediaElement::WakeLockBoolWrapper::TimerCallback(nsITimer* aTimer,
+                                                     void* aClosure)
+{
+  WakeLockBoolWrapper* wakeLock = static_cast<WakeLockBoolWrapper*>(aClosure);
+  wakeLock->mOuter->WakeLockRelease();
+  wakeLock->mTimer = nullptr;
+}
+
 void
 HTMLMediaElement::WakeLockCreate()
 {

content/html/content/test/test_audio_wakelock.html

@@ -20,8 +20,6 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=868943
 
 /** Test for Bug 868943 **/
 
-SpecialPowers.addPermission("power", true, document);
-
 function testAudioPlayPause() {
   var lockState = true;
   var count = 0;
@@ -32,9 +30,11 @@ function testAudioPlayPause() {
   audio.src = "wakelock.ogg";
   content.appendChild(audio);
 
+  var startDate;
   audio.addEventListener('progress', function() {
     lockState = false;
     audio.pause();
+    startDate = new Date();
   });
 
   navigator.mozPower.addWakeLockListener(function testAudioPlayListener(topic, state) {
@@ -49,6 +49,9 @@ function testAudioPlayPause() {
     // count == 2 is when the cpu wakelock is released
 
     if (count == 2) {
+      var diffDate = (new Date() - startDate);
+      ok(diffDate > 200, "There was at least 200 milliseconds between the stop and the wakelock release");
+
       content.removeChild(audio);
       navigator.mozPower.removeWakeLockListener(testAudioPlayListener);
       runTests();
@@ -68,6 +71,11 @@ function testAudioPlay() {
   audio.src = "wakelock.ogg";
   content.appendChild(audio);
 
+  var startDate;
+  audio.addEventListener('progress', function() {
+    startDate = new Date();
+  });
+
   navigator.mozPower.addWakeLockListener(function testAudioPlayListener(topic, state) {
     is(topic, "cpu", "Audio element locked the target == cpu");
     var locked = state == "locked-foreground" ||
@@ -84,6 +92,9 @@ function testAudioPlay() {
       // The next step is to unlock the resource.
       lockState = false;
     } else if (count == 2) {
+      var diffDate = (new Date() - startDate);
+      ok(diffDate > 200, "There was at least 200 milliseconds between the stop and the wakelock release");
+
       content.removeChild(audio);
       navigator.mozPower.removeWakeLockListener(testAudioPlayListener);
       runTests();
@@ -104,8 +115,10 @@ function runTests() {
   test();
 };
 
+SpecialPowers.addPermission("power", true, document);
+SpecialPowers.pushPrefEnv({"set": [["media.wakelock_timeout", 500]]}, runTests);
+
 SimpleTest.waitForExplicitFinish();
-runTests();
 
 </script>
 </pre>

content/html/content/test/test_video_wakelock.html

@@ -20,8 +20,6 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=868943
 
 /** Test for Bug 868943 **/
 
-SpecialPowers.addPermission("power", true, document);
-
 function testVideoPlayPause() {
   var lockState = true;
   var count = 0;
@@ -32,6 +30,15 @@ function testVideoPlayPause() {
   video.src = "wakelock.ogv";
   content.appendChild(video);
 
+  var startDate;
+  video.addEventListener('progress', function() {
+    startDate = new Date();
+
+    // The next step is to unlock the resource.
+    lockState = false;
+    video.pause();
+  });
+
   navigator.mozPower.addWakeLockListener(function testVideoPlayPauseListener(topic, state) {
     is(topic, "screen", "Video element locked the target == screen");
     var locked = state == "locked-foreground" ||
@@ -40,11 +47,10 @@ function testVideoPlayPause() {
     is(locked, lockState, "Video element locked the screen - paused");
     count++;
 
-    if (count == 1) {
-      // The next step is to unlock the resource.
-      lockState = false;
-      video.pause();
-    } else if (count == 2) {
+    if (count == 2) {
+      var diffDate = (new Date() - startDate);
+      ok(diffDate > 200, "There was at least 200 milliseconds between the stop and the wakelock release");
+
       content.removeChild(video);
       navigator.mozPower.removeWakeLockListener(testVideoPlayPauseListener);
       runTests();
@@ -64,6 +70,11 @@ function testVideoPlay() {
   video.src = "wakelock.ogv";
   content.appendChild(video);
 
+  var startDate;
+  video.addEventListener('progress', function() {
+    startDate = new Date();
+  });
+
   navigator.mozPower.addWakeLockListener(function testVideoPlayListener(topic, state) {
     is(topic, "screen", "Video element locked the target == screen");
     var locked = state == "locked-foreground" ||
@@ -76,6 +87,9 @@ function testVideoPlay() {
       // The next step is to unlock the resource.
       lockState = false;
     } else if (count == 2) {
+      var diffDate = (new Date() - startDate);
+      ok(diffDate > 200, "There was at least milliseconds between the stop and the wakelock release");
+
       content.removeChild(video);
       navigator.mozPower.removeWakeLockListener(testVideoPlayListener);
       runTests();
@@ -96,8 +110,10 @@ function runTests() {
   test();
 };
 
+SpecialPowers.addPermission("power", true, document);
+SpecialPowers.pushPrefEnv({"set": [["media.wakelock_timeout", 500]]}, runTests);
+
 SimpleTest.waitForExplicitFinish();
-runTests();
 
 </script>
 </pre>

modules/libpref/src/init/all.js

@@ -152,6 +152,9 @@ pref("media.cache_size", 512000);
 // Master HTML5 media volume scale.
 pref("media.volume_scale", "1.0");
 
+// Timeout for wakelock release
+pref("media.wakelock_timeout", 2000);
+
 #ifdef MOZ_WMF
 pref("media.windows-media-foundation.enabled", true);
 pref("media.windows-media-foundation.use-dxva", true);