Bug 482885. Ensure media channels are in the document loadgroup. r=bzbarsky,r+sr=roc

--HG--
extra : rebase_source : da14c85f0efd3eda24739161f8195d24117da261

content/html/content/public/nsHTMLMediaElement.h

@@ -42,6 +42,7 @@
 #include "nsThreadUtils.h"
 #include "nsIDOMRange.h"
 #include "nsCycleCollectionParticipant.h"
+#include "nsILoadGroup.h"
 
 // Define to output information on decoding and painting framerate
 /* #define DEBUG_FRAME_RATE 1 */
@@ -228,6 +229,11 @@ public:
    */
   PRUint32 GetCurrentLoadID() { return mCurrentLoadID; }
 
+  /**
+   * Returns the load group for this media element's owner document.
+   * XXX XBL2 issue.
+   */
+  already_AddRefed<nsILoadGroup> GetDocumentLoadGroup();
 
 protected:
   class MediaLoadListener;
@@ -307,6 +313,10 @@ protected:
 
   nsRefPtr<nsMediaDecoder> mDecoder;
 
+  // Holds a reference to the first channel we open to the media resource.
+  // Once the decoder is created, control over the channel passes to the
+  // decoder, and we null out this reference. We must store this in case
+  // we need to cancel the channel before control of it passes to the decoder.
   nsCOMPtr<nsIChannel> mChannel;
 
   // Error attribute

content/html/content/src/nsHTMLMediaElement.cpp

@@ -498,10 +498,11 @@ nsresult nsHTMLMediaElement::LoadResource(nsIURI* aURI)
   NS_ENSURE_SUCCESS(rv,rv);
   if (NS_CP_REJECTED(shouldLoad)) return NS_ERROR_FAILURE;
 
+  nsCOMPtr<nsILoadGroup> loadGroup = GetDocumentLoadGroup();
   rv = NS_NewChannel(getter_AddRefs(mChannel),
                      aURI,
                      nsnull,
-                     nsnull,
+                     loadGroup,
                      nsnull,
                      nsIRequest::LOAD_NORMAL);
   NS_ENSURE_SUCCESS(rv,rv);
@@ -1118,6 +1119,10 @@ nsresult nsHTMLMediaElement::InitializeDecoderForChannel(nsIChannel *aChannel,
   if (NS_FAILED(rv))
     return rv;
 
+  // Decoder successfully created, its nsMediaStream now has responsibility
+  // for the channel, and the owning reference.
+  mChannel = nsnull;
+
   mDecoder->SetVolume(mMuted ? 0.0 : mVolume);
 
   if (!mPaused) {
@@ -1577,8 +1582,17 @@ void nsHTMLMediaElement::ChangeDelayLoadStatus(PRBool aDelay) {
     mLoadBlockedDoc = GetOwnerDoc();
     mLoadBlockedDoc->BlockOnload();
   } else {
+    if (mDecoder) {
+      mDecoder->MoveLoadsToBackground();
+    }
     NS_ASSERTION(mLoadBlockedDoc, "Need a doc to block on");
     mLoadBlockedDoc->UnblockOnload(PR_FALSE);
     mLoadBlockedDoc = nsnull;
   }
 }
+
+already_AddRefed<nsILoadGroup> nsHTMLMediaElement::GetDocumentLoadGroup()
+{
+  nsIDocument* doc = GetOwnerDoc();
+  return doc ? doc->GetDocumentLoadGroup() : nsnull;
+}

content/media/video/public/nsMediaDecoder.h

@@ -223,6 +223,13 @@ class nsMediaDecoder : public nsIObserver
   // if it's available.
   nsHTMLMediaElement* GetMediaElement();
 
+  // Moves any existing channel loads into the background, so that they don't
+  // block the load event. This is called when we stop delaying the load
+  // event. Any new loads initiated (for example to seek) will also be in the
+  // background. Implementations of this must call MoveLoadsToBackground() on
+  // their nsMediaStream.
+  virtual void MoveLoadsToBackground()=0;
+
 protected:
 
   // Start timer to update download progress information.

content/media/video/public/nsMediaStream.h

@@ -198,6 +198,10 @@ public:
   virtual nsresult Seek(PRInt32 aWhence, PRInt64 aOffset) = 0;
   // Report the current offset in bytes from the start of the stream.
   virtual PRInt64 Tell() = 0;
+  // Moves any existing channel loads into the background, so that they don't
+  // block the load event. Any new loads initiated (for example to seek)
+  // will also be in the background.
+  void MoveLoadsToBackground();
 
   // These can be called on any thread.
   // Cached blocks associated with this stream will not be evicted
@@ -243,7 +247,8 @@ protected:
   nsMediaStream(nsMediaDecoder* aDecoder, nsIChannel* aChannel, nsIURI* aURI) :
     mDecoder(aDecoder),
     mChannel(aChannel),
-    mURI(aURI)
+    mURI(aURI),
+    mLoadInBackground(PR_FALSE)
   {
     MOZ_COUNT_CTOR(nsMediaStream);
   }
@@ -268,6 +273,10 @@ protected:
   // URI in case the stream needs to be re-opened. Access from
   // main thread only.
   nsCOMPtr<nsIURI> mURI;
+
+  // PR_TRUE if MoveLoadsToBackground() has been called, i.e. the load event
+  // has been fired, and all channel loads will be in the background.
+  PRPackedBool mLoadInBackground;
 };
 
 /**

content/media/video/public/nsOggDecoder.h

@@ -372,6 +372,9 @@ class nsOggDecoder : public nsMediaDecoder
   // main thread only.
   virtual void Resume();
 
+  // Tells our nsMediaStream to put all loads in the background.
+  virtual void MoveLoadsToBackground();
+
 protected:
 
   // Returns the monitor for other threads to synchronise access to

content/media/video/public/nsWaveDecoder.h

@@ -220,6 +220,9 @@ class nsWaveDecoder : public nsMediaDecoder
   // Change the element's ready state as necessary. Main thread only.
   void UpdateReadyStateForData();
 
+  // Tells mStream to put all loads in the background.
+  virtual void MoveLoadsToBackground();
+
 private:
   // Notifies the element that seeking has started.
   void SeekingStarted();

content/media/video/src/nsMediaStream.cpp

@@ -457,15 +457,27 @@ nsMediaChannelStream::CacheClientSeek(PRInt64 aOffset)
 {
   NS_ASSERTION(NS_IsMainThread(), "Don't call on main thread");
 
+  nsLoadFlags loadFlags =
+    nsICachingChannel::LOAD_BYPASS_LOCAL_CACHE_IF_BUSY |
+    (mLoadInBackground ? nsIRequest::LOAD_BACKGROUND : 0);
+
   CloseChannel();
-  if (!mDecoder->GetMediaElement()) {
+
+  nsHTMLMediaElement* element = mDecoder->GetMediaElement();
+  if (!element) {
     // The decoder is being shut down, so don't bother opening a new channel
     return NS_OK;
   }
+  nsCOMPtr<nsILoadGroup> loadGroup = element->GetDocumentLoadGroup();
+  NS_ENSURE_TRUE(loadGroup, NS_ERROR_NULL_POINTER);
 
   nsresult rv =
-    NS_NewChannel(getter_AddRefs(mChannel), mURI, nsnull, nsnull, nsnull,
-                  nsICachingChannel::LOAD_BYPASS_LOCAL_CACHE_IF_BUSY);
+    NS_NewChannel(getter_AddRefs(mChannel),
+                  mURI,
+                  nsnull,
+                  loadGroup,
+                  nsnull,
+                  loadFlags);
   if (NS_FAILED(rv))
     return rv;
   return OpenChannel(nsnull, aOffset);
@@ -789,10 +801,13 @@ nsMediaStream::Open(nsMediaDecoder* aDecoder, nsIURI* aURI,
   if (aChannel) {
     channel = aChannel;
   } else {
+    nsHTMLMediaElement* element = aDecoder->GetMediaElement();
+    NS_ENSURE_TRUE(element, NS_ERROR_NULL_POINTER);
+    nsCOMPtr<nsILoadGroup> loadGroup = element->GetDocumentLoadGroup();
     nsresult rv = NS_NewChannel(getter_AddRefs(channel), 
                                 aURI, 
                                 nsnull,
-                                nsnull,
+                                loadGroup,
                                 nsnull,
                                 nsICachingChannel::LOAD_BYPASS_LOCAL_CACHE_IF_BUSY);
     NS_ENSURE_SUCCESS(rv, rv);
@@ -826,3 +841,44 @@ already_AddRefed<nsIPrincipal> nsMediaStream::GetCurrentPrincipal()
   secMan->GetChannelPrincipal(mChannel, getter_AddRefs(principal));
   return principal.forget();
 }
+
+void nsMediaStream::MoveLoadsToBackground() {
+  NS_ASSERTION(!mLoadInBackground, "Why are you calling this more than once?");
+  mLoadInBackground = PR_TRUE;
+  if (!mChannel) {
+    // No channel, resource is probably already loaded.
+    return;
+  }
+
+  nsresult rv;
+  nsHTMLMediaElement* element = mDecoder->GetMediaElement();
+  if (!element) {
+    NS_WARNING("Null element in nsMediaStream::MoveLoadsToBackground()");
+    return;
+  }
+  nsCOMPtr<nsILoadGroup> loadGroup;
+  rv = mChannel->GetLoadGroup(getter_AddRefs(loadGroup));
+  NS_ASSERTION(NS_SUCCEEDED(rv), "GetLoadGroup() failed!");
+  nsresult status;
+  mChannel->GetStatus(&status);
+  // Note: if (NS_FAILED(status)), the channel won't be in the load group.
+  PRBool isPending = PR_FALSE;
+  if (loadGroup &&
+      NS_SUCCEEDED(status) &&
+      NS_SUCCEEDED(mChannel->IsPending(&isPending)) &&
+      isPending) {
+    rv = loadGroup->RemoveRequest(mChannel, nsnull, status);
+    NS_ASSERTION(NS_SUCCEEDED(rv), "RemoveRequest() failed!");
+
+    nsLoadFlags loadFlags;
+    rv = mChannel->GetLoadFlags(&loadFlags);
+    NS_ASSERTION(NS_SUCCEEDED(rv), "GetLoadFlags() failed!");
+
+    loadFlags |= nsIRequest::LOAD_BACKGROUND;
+    rv = mChannel->SetLoadFlags(loadFlags);
+    NS_ASSERTION(NS_SUCCEEDED(rv), "SetLoadFlags() failed!");
+
+    rv = loadGroup->AddRequest(mChannel, nsnull);
+    NS_ASSERTION(NS_SUCCEEDED(rv), "AddRequest() failed!");
+  }
+}

content/media/video/src/nsOggDecoder.cpp

@@ -1991,3 +1991,11 @@ void nsOggDecoder::StartProgressUpdates()
     mDecoderPosition = mPlaybackPosition = mReader->Stream()->Tell();
   }
 }
+
+void nsOggDecoder::MoveLoadsToBackground()
+{
+  if (mReader && mReader->Stream()) {
+    mReader->Stream()->MoveLoadsToBackground();
+  }
+}
+

content/media/video/src/nsWaveDecoder.cpp

@@ -1622,3 +1622,11 @@ nsWaveDecoder::Resume()
     mStream->Resume();
   }
 }
+
+void 
+nsWaveDecoder::MoveLoadsToBackground()
+{
+  if (mStream) {
+    mStream->MoveLoadsToBackground();
+  }
+}