Changeset 148064 in webkit

Timestamp:

Apr 9, 2013 4:52:23 PM (11 years ago)

Author:

jer.noble@apple.com

Message:

hang in mediaSelectionGroupForMediaCharacteristic
​https://bugs.webkit.org/show_bug.cgi?id=114054

Reviewed by Eric Carlson.

No new tests; Fixes sporadic hangs in media/ tests.

-[AVURLAsset mediaSelectionGroupForMediaCharacteristic:] can deadlock in certain situations: When AVURLAsset
posts a synchronous AVAssetResourceLoader notification to the main thread, calling -mediaSelectionGroupForMediaCharacteristic:
on the main thread requires IO to occur if the media characteristics are not yet loaded. Instead of blocking,
bail out early if the media characteristics are not yet known.

Add a new method, safeMediaSelectionGroupForLegibleMedia(), which first checks selection group availability
before calling mediaSelectionGroupForMediaCharacteristic:.

• platform/graphics/avfoundation/objc/MediaPlayerPrivateAVFoundationObjC.h:

(MediaPlayerPrivateAVFoundationObjC):

• platform/graphics/avfoundation/objc/MediaPlayerPrivateAVFoundationObjC.mm:

(WebCore::MediaPlayerPrivateAVFoundationObjC::safeMediaSelectionGroupForLegibleMedia): Added.
(WebCore::MediaPlayerPrivateAVFoundationObjC::createAVPlayerItem): Use new safe method.
(WebCore::MediaPlayerPrivateAVFoundationObjC::tracksChanged): Ditto.
(WebCore::MediaPlayerPrivateAVFoundationObjC::processTextTracks): Ditto.
(WebCore::MediaPlayerPrivateAVFoundationObjC::setCurrentTrack): Ditto.

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• platform/graphics/avfoundation/objc/MediaPlayerPrivateAVFoundationObjC.h (modified) (2 diffs)
• platform/graphics/avfoundation/objc/MediaPlayerPrivateAVFoundationObjC.mm (modified) (4 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2013-04-09  Jer Noble  <jer.noble@apple.com>
+
+        hang in mediaSelectionGroupForMediaCharacteristic
+        https://bugs.webkit.org/show_bug.cgi?id=114054
+
+        Reviewed by Eric Carlson.
+
+        No new tests; Fixes sporadic hangs in media/ tests.
+
+        -[AVURLAsset mediaSelectionGroupForMediaCharacteristic:] can deadlock in certain situations: When AVURLAsset
+        posts a synchronous AVAssetResourceLoader notification to the main thread, calling -mediaSelectionGroupForMediaCharacteristic:
+        on the main thread requires IO to occur if the media characteristics are not yet loaded. Instead of blocking,
+        bail out early if the media characteristics are not yet known.
+        
+        Add a new method, safeMediaSelectionGroupForLegibleMedia(), which first checks selection group availability
+        before calling mediaSelectionGroupForMediaCharacteristic:.
+
+        * platform/graphics/avfoundation/objc/MediaPlayerPrivateAVFoundationObjC.h:
+        (MediaPlayerPrivateAVFoundationObjC):
+        * platform/graphics/avfoundation/objc/MediaPlayerPrivateAVFoundationObjC.mm:
+        (WebCore::MediaPlayerPrivateAVFoundationObjC::safeMediaSelectionGroupForLegibleMedia): Added.
+        (WebCore::MediaPlayerPrivateAVFoundationObjC::createAVPlayerItem): Use new safe method.
+        (WebCore::MediaPlayerPrivateAVFoundationObjC::tracksChanged): Ditto.
+        (WebCore::MediaPlayerPrivateAVFoundationObjC::processTextTracks): Ditto.
+        (WebCore::MediaPlayerPrivateAVFoundationObjC::setCurrentTrack): Ditto.
+
 2013-04-09  Chris Fleizach  <cfleizach@apple.com>
 

trunk/Source/WebCore/platform/graphics/avfoundation/objc/MediaPlayerPrivateAVFoundationObjC.h

@@ -33 +33 @@
 
 OBJC_CLASS AVURLAsset;
+OBJC_CLASS AVMediaSelectionGroup;
 OBJC_CLASS AVPlayer;
 OBJC_CLASS AVPlayerItem;
@@ -167 +168 @@
     void processTextTracks();
     void clearTextTracks();
+    AVMediaSelectionGroup* safeMediaSelectionGroupForLegibleMedia();
 #endif
 

trunk/Source/WebCore/platform/graphics/avfoundation/objc/MediaPlayerPrivateAVFoundationObjC.mm

@@ -467 +467 @@
     // We enabled automatic media selection because we want alternate audio tracks to be enabled/disabled automatically,
     // but set the selected legible track to nil so text tracks will not be automatically configured.
-    [m_avPlayerItem.get() selectMediaOption:nil inMediaSelectionGroup:[m_avAsset.get() mediaSelectionGroupForMediaCharacteristic:AVMediaCharacteristicLegible]];
+    [m_avPlayerItem.get() selectMediaOption:nil inMediaSelectionGroup:safeMediaSelectionGroupForLegibleMedia()];
 
     [m_legibleOutput.get() setDelegate:m_objcObserver.get() queue:dispatch_get_main_queue()];
@@ -986 +986 @@
 #if HAVE(AVFOUNDATION_TEXT_TRACK_SUPPORT)
     if (!hasCaptions && m_legibleOutput) {
-        AVMediaSelectionGroupType *legibleGroup = [m_avAsset.get() mediaSelectionGroupForMediaCharacteristic:AVMediaCharacteristicLegible];
+        AVMediaSelectionGroupType *legibleGroup = safeMediaSelectionGroupForLegibleMedia();
         hasCaptions = [[AVMediaSelectionGroup playableMediaSelectionOptionsFromArray:[legibleGroup options]] count];
     }
@@ -1297 +1297 @@
 }
 
+AVMediaSelectionGroupType* MediaPlayerPrivateAVFoundationObjC::safeMediaSelectionGroupForLegibleMedia()
+{
+    if (!m_avAsset)
+        return nil;
+
+    if ([m_avAsset.get() statusOfValueForKey:@"availableMediaCharacteristicsWithMediaSelectionOptions" error:NULL] != AVKeyValueStatusLoaded)
+        return nil;
+
+    return [m_avAsset.get() mediaSelectionGroupForMediaCharacteristic:AVMediaCharacteristicLegible];
+}
+
 void MediaPlayerPrivateAVFoundationObjC::processTextTracks()
 {
-    AVMediaSelectionGroupType *legibleGroup = [m_avAsset.get() mediaSelectionGroupForMediaCharacteristic:AVMediaCharacteristicLegible];
+    AVMediaSelectionGroupType *legibleGroup = safeMediaSelectionGroupForLegibleMedia();
     if (!legibleGroup) {
         LOG(Media, "MediaPlayerPrivateAVFoundationObjC::processTextTracks(%p) - nil mediaSelectionGroup", this);
@@ -1369 +1380 @@
     LOG(Media, "MediaPlayerPrivateAVFoundationObjC::setCurrentTrack(%p) - selecting media option %p, language = %s", this, mediaSelectionOption, [[[mediaSelectionOption locale] localeIdentifier] UTF8String]);
 
-    [m_avPlayerItem.get() selectMediaOption:mediaSelectionOption inMediaSelectionGroup:[m_avAsset.get() mediaSelectionGroupForMediaCharacteristic:AVMediaCharacteristicLegible]];
+    [m_avPlayerItem.get() selectMediaOption:mediaSelectionOption inMediaSelectionGroup:safeMediaSelectionGroupForLegibleMedia()];
     m_currentTrack = trackPrivate;
 }