Bug 846687 - Set the transport as non-seekable if the server sends Accept-Ranges, but no Content-Length. r=cpearce

content/media/MediaDecoder.cpp

@@ -1262,10 +1262,10 @@ void MediaDecoder::SetMediaSeekable(bool aMediaSeekable) {
 
 void MediaDecoder::SetTransportSeekable(bool aTransportSeekable)
 {
-  MOZ_ASSERT(NS_IsMainThread());
+  ReentrantMonitorAutoEnter mon(GetReentrantMonitor());
+  MOZ_ASSERT(NS_IsMainThread() || OnDecodeThread());
   mTransportSeekable = aTransportSeekable;
   if (mDecoderStateMachine) {
-    ReentrantMonitorAutoEnter mon(GetReentrantMonitor());
     mDecoderStateMachine->SetTransportSeekable(aTransportSeekable);
   }
 }

content/media/ogg/OggReader.cpp

@@ -365,6 +365,12 @@ nsresult OggReader::ReadMetadata(VideoInfo* aInfo,
         LOG(PR_LOG_DEBUG, ("Got Ogg duration from seeking to end %lld", endTime));
       }
       mDecoder->GetResource()->EndSeekingForMetadata();
+    } else if (mDecoder->GetMediaDuration() == -1) {
+      // We don't have a duration, and we don't know enough about the resource
+      // to try a seek. Abort trying to get a duration. This happens for example
+      // when the server says it accepts range requests, but does not give us a
+      // Content-Length.
+      mDecoder->SetTransportSeekable(false);
     }
   } else {
     return NS_ERROR_FAILURE;