third_party/WebKit/Source/modules/mediacapturefromelement/HTMLMediaElementCapture.cpp

// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "modules/mediacapturefromelement/HTMLMediaElementCapture.h"

#include "core/dom/ExceptionCode.h"
#include "core/html/HTMLMediaElement.h"
#include "core/html/track/AudioTrackList.h"
#include "core/html/track/VideoTrackList.h"
#include "modules/encryptedmedia/HTMLMediaElementEncryptedMedia.h"
#include "modules/encryptedmedia/MediaKeys.h"
#include "modules/mediastream/MediaStream.h"
#include "modules/mediastream/MediaStreamRegistry.h"
#include "platform/mediastream/MediaStreamCenter.h"
#include "public/platform/Platform.h"
#include "public/platform/WebMediaStream.h"
#include "public/platform/WebMediaStreamTrack.h"

namespace blink {

// static
MediaStream* HTMLMediaElementCapture::captureStream(
    HTMLMediaElement& element,
    ExceptionState& exceptionState) {
  if (element.currentSrc().isNull()) {
    exceptionState.throwDOMException(NotSupportedError,
                                     "The media element must have a source.");
    return nullptr;
  }

  // Avoid capturing from EME-protected Media Elements.
  if (HTMLMediaElementEncryptedMedia::mediaKeys(element)) {
    // This exception is not defined in the spec, see
    // https://github.com/w3c/mediacapture-fromelement/issues/20.
    exceptionState.throwDOMException(NotSupportedError,
                                     "Stream capture not supported with EME");
    return nullptr;
  }

  // If |element| is actually playing a MediaStream, just clone it.
  if (HTMLMediaElement::isMediaStreamURL(element.currentSrc().getString())) {
    return MediaStream::create(
        element.getExecutionContext(),
        MediaStreamRegistry::registry().lookupMediaStreamDescriptor(
            element.currentSrc().getString()));
  }

  WebMediaStream webStream;
  webStream.initialize(WebVector<WebMediaStreamTrack>(),
                       WebVector<WebMediaStreamTrack>());
  MediaStreamCenter::instance().didCreateMediaStream(webStream);

  if (element.hasVideo())
    Platform::current()->createHTMLVideoElementCapturer(
        &webStream, element.webMediaPlayer());
  if (element.hasAudio())
    Platform::current()->createHTMLAudioElementCapturer(
        &webStream, element.webMediaPlayer());
  return MediaStream::create(element.getExecutionContext(), webStream);
}

}  // namespace blink