Added function to implement Coded Frame Eviction Algorithm

Source/modules/mediasource/SourceBuffer.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 495 matching lines @@
     //  1. If this object has been removed from the sourceBuffers attribute of the parent media source then throw an InvalidStateError exception and abort these steps.
     //  2. If the updating attribute equals true, then throw an InvalidStateError exception and abort these steps.
     if (throwExceptionIfRemovedOrUpdating(isRemoved(), m_updating, exceptionState))
         return;
 
     TRACE_EVENT_ASYNC_BEGIN1("media", "SourceBuffer::appendBuffer", this, "size", size);
 
     //  3. If the readyState attribute of the parent media source is in the "ended" state then run the following steps: ...
     m_source->openIfInEndedState();
 
-    //  Steps 4-5 - end "prepare append" algorithm.
+    //  4. Run the coded frame eviction algorithm.
+    if (!evictCodedFrames()) {
+        //  5. If the buffer full flag equals true, then throw a QUOTA_EXCEEDED_ERR exception and abort these steps.

[philipj_slow, 2014/12/10 09:28:26]

I see that we don't have an explicit "buffer full flag" in Chromium or Blink.
That would have made this code more like the spec, but I guess that's OK.

[kjoswiak, 2014/12/10 19:11:45]

Though other thing I considered doing is adding a separate function that just
queried the buffer, asking if its full, instead of relying on this new functions
return value. It felt a little redundant though, so I left it out.

+        exceptionState.throwDOMException(QuotaExceededError, "The SourceBuffer is full, and cannot free space append additional buffers.");

[philipj_slow, 2014/12/10 09:28:26]

missing "to"

[kjoswiak, 2014/12/10 19:11:45]

Done.

+        return;
+    }
 
     // 2. Add data to the end of the input buffer.
     ASSERT(data || size == 0);
     if (data)
         m_pendingAppendData.append(data, size);
     m_pendingAppendDataOffset = 0;
 
     // 3. Set the updating attribute to true.
     m_updating = true;
 
@@ skipping 77 matching lines @@
     m_pendingRemoveStart = -1;
     m_pendingRemoveEnd = -1;
 
     // 11. Queue a task to fire a simple event named update at this SourceBuffer object.
     scheduleEvent(EventTypeNames::update);
 
     // 12. Queue a task to fire a simple event named updateend at this SourceBuffer object.
     scheduleEvent(EventTypeNames::updateend);
 }
 
+bool SourceBuffer::evictCodedFrames()
+{
+    return m_webSourceBuffer->evictCodedFrames();
+}
+
 void SourceBuffer::appendStreamInternal(PassRefPtrWillBeRawPtr<Stream> stream, ExceptionState& exceptionState)
 {
     // Section 3.2 appendStream()
     // https://dvcs.w3.org/hg/html-media/raw-file/default/media-source/media-source.html#widl-SourceBuffer-appendStream-void-Stream-stream-unsigned-long-long-maxSize
     // (0. If the stream has been neutered, then throw an InvalidAccessError exception and abort these steps.)
     if (stream->isNeutered()) {
         exceptionState.throwDOMException(InvalidAccessError, "The stream provided has been neutered.");
         return;
     }
 
     // 1. Run the prepare append algorithm.
     //  Section 3.5.4 Prepare Append Algorithm.
     //  https://dvcs.w3.org/hg/html-media/raw-file/default/media-source/media-source.html#sourcebuffer-prepare-append
     //  1. If this object has been removed from the sourceBuffers attribute of the parent media source then throw an InvalidStateError exception and abort these steps.
     //  2. If the updating attribute equals true, then throw an InvalidStateError exception and abort these steps.
     if (throwExceptionIfRemovedOrUpdating(isRemoved(), m_updating, exceptionState))
         return;
 
     TRACE_EVENT_ASYNC_BEGIN0("media", "SourceBuffer::appendStream", this);
 
     //  3. If the readyState attribute of the parent media source is in the "ended" state then run the following steps: ...
     m_source->openIfInEndedState();
 
-    // Steps 4-5 of the prepare append algorithm are handled by m_webSourceBuffer.
+    // 4. Run the coded frame eviction algorithm.
+    if (!evictCodedFrames()) {
+        //  5. If the buffer full flag equals true, then throw a QUOTA_EXCEEDED_ERR exception and abort these steps.
+        // TODO(kjoswiak): Is this accurate? Are we actually appending data, or appending a data source?

[philipj_slow, 2014/12/10 09:28:26]

No TODO(user) in Blink, just FIXME. Even better, investigate it and remove the
comment :)

[kjoswiak, 2014/12/10 19:11:45]

whoops meant to remove this, I had actually come to a decision about it,
specifically that since MSE says to run prepare append and this is in the spec
for prepare append its probably best to just leave it in. Done.

+        exceptionState.throwDOMException(QuotaExceededError, "The SourceBuffer is full, and cannot free space to append stream.");
+        return;
+    }
 
     // 2. Set the updating attribute to true.
     m_updating = true;
 
     // 3. Queue a task to fire a simple event named updatestart at this SourceBuffer object.
     scheduleEvent(EventTypeNames::updatestart);
 
     // 4. Asynchronously run the stream append loop algorithm with stream and maxSize.
 
     stream->neuter();
@@ skipping 96 matching lines @@
 
 void SourceBuffer::trace(Visitor* visitor)
 {
     visitor->trace(m_source);
     visitor->trace(m_stream);
     visitor->trace(m_asyncEventQueue);
     EventTargetWithInlineData::trace(visitor);
 }
 
 } // namespace blink