Move the exception logic to the AudioNode creator

third_party/WebKit/Source/modules/webaudio/MediaStreamAudioSourceNode.cpp

 /*
  * Copyright (C) 2012, 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:
  * 1.  Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "modules/webaudio/MediaStreamAudioSourceNode.h"
+
+#include "core/dom/ExceptionCode.h"
 #include "modules/webaudio/AbstractAudioContext.h"
 #include "modules/webaudio/AudioNodeOutput.h"
 #include "platform/Logging.h"
 #include "wtf/Locker.h"
 
 namespace blink {
 
 MediaStreamAudioSourceHandler::MediaStreamAudioSourceHandler(AudioNode& node, MediaStream& mediaStream, MediaStreamTrack* audioTrack, PassOwnPtr<AudioSourceProvider> audioSourceProvider)
     : AudioHandler(NodeTypeMediaStreamAudioSource, node, node.context()->sampleRate())
     , m_mediaStream(mediaStream)
@@ skipping 71 matching lines @@
 }
 
 // ----------------------------------------------------------------
 
 MediaStreamAudioSourceNode::MediaStreamAudioSourceNode(AbstractAudioContext& context, MediaStream& mediaStream, MediaStreamTrack* audioTrack, PassOwnPtr<AudioSourceProvider> audioSourceProvider)
     : AudioSourceNode(context)
 {
     setHandler(MediaStreamAudioSourceHandler::create(*this, mediaStream, audioTrack, std::move(audioSourceProvider)));
 }
 
-MediaStreamAudioSourceNode* MediaStreamAudioSourceNode::create(AbstractAudioContext& context, MediaStream& mediaStream, MediaStreamTrack* audioTrack, PassOwnPtr<AudioSourceProvider> audioSourceProvider)
+MediaStreamAudioSourceNode* MediaStreamAudioSourceNode::create(AbstractAudioContext& context, MediaStream& mediaStream, ExceptionState& exceptionState)
 {
-    return new MediaStreamAudioSourceNode(context, mediaStream, audioTrack, std::move(audioSourceProvider));
+    ASSERT(isMainThread());

[hongchan, 2016/05/13 01:20:12]

DCHECK.

[Raymond Toy, 2016/05/20 23:12:00]

Done.

+
+    if (context.isContextClosed()) {
+        context.throwExceptionForClosedState(exceptionState);
+        return nullptr;
+    }
+
+    MediaStreamTrackVector audioTracks = mediaStream.getAudioTracks();
+    if (audioTracks.isEmpty()) {
+        exceptionState.throwDOMException(
+            InvalidStateError,
+            "MediaStream has no audio track");
+        return nullptr;
+    }
+
+    // Use the first audio track in the media stream.
+    MediaStreamTrack* audioTrack = audioTracks[0];
+    OwnPtr<AudioSourceProvider> provider = audioTrack->createWebAudioSource();
+
+    MediaStreamAudioSourceNode* node = new MediaStreamAudioSourceNode(context, mediaStream, audioTrack, provider.release());

[hongchan, 2016/05/13 01:20:12]

Over 80 cols. Let's wrap these arguments.

+
+    if (node) {
+        // FIXME: Only stereo streams are supported right now. We should be able to accept multi-channel streams.

[hongchan, 2016/05/13 01:20:12]

Over 80 cols. Let's change it to 'TODO'. You can put my ID here.

[Raymond Toy, 2016/05/20 23:12:00]

Done.

+        node->setFormat(2, context.sampleRate());
+        // context keeps reference until node is disconnected
+        context.notifySourceNodeStartedProcessing(node);
+    }
+
+    return node;

[hongchan, 2016/05/13 01:20:12]

We should return nullptr when |node| is invalid and do the rest otherwise.

 }
 
 DEFINE_TRACE(MediaStreamAudioSourceNode)
 {
     AudioSourceProviderClient::trace(visitor);
     AudioSourceNode::trace(visitor);
 }
 
 MediaStreamAudioSourceHandler& MediaStreamAudioSourceNode::mediaStreamAudioSourceHandler() const
 {
     return static_cast<MediaStreamAudioSourceHandler&>(handler());
 }
 
 MediaStream* MediaStreamAudioSourceNode::getMediaStream() const
 {
     return mediaStreamAudioSourceHandler().getMediaStream();
 }
 
 void MediaStreamAudioSourceNode::setFormat(size_t numberOfChannels, float sourceSampleRate)
 {
     mediaStreamAudioSourceHandler().setFormat(numberOfChannels, sourceSampleRate);
 }
 
 } // namespace blink