src/cobalt/dom/html_media_element.h

// Copyright 2015 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef COBALT_DOM_HTML_MEDIA_ELEMENT_H_
#define COBALT_DOM_HTML_MEDIA_ELEMENT_H_

#include <string>

#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.h"
#include "base/optional.h"
#include "base/threading/thread_checker.h"
#include "base/timer.h"
#include "cobalt/dom/event_queue.h"
#include "cobalt/dom/html_element.h"
#include "cobalt/dom/media_error.h"
#include "cobalt/dom/time_ranges.h"
#include "cobalt/dom/uint8_array.h"
#include "cobalt/loader/image/image_cache.h"
#include "cobalt/script/exception_state.h"
#include "googleurl/src/gurl.h"
#if defined(COBALT_MEDIA_SOURCE_2016)
#include "cobalt/dom/eme/media_keys.h"
#include "cobalt/media/player/web_media_player.h"
#else  // defined(COBALT_MEDIA_SOURCE_2016)
#include "cobalt/dom/media_source.h"
#include "media/player/web_media_player.h"
#endif  // defined(COBALT_MEDIA_SOURCE_2016)

namespace cobalt {
namespace dom {

class MediaSource;

#if defined(COBALT_MEDIA_SOURCE_2016)
typedef media::ChunkDemuxer ChunkDemuxer;
typedef media::WebMediaPlayer WebMediaPlayer;
typedef media::WebMediaPlayerClient WebMediaPlayerClient;
#else   // defined(COBALT_MEDIA_SOURCE_2016)
typedef ::media::WebMediaPlayer WebMediaPlayer;
typedef ::media::WebMediaPlayerClient WebMediaPlayerClient;
#endif  // defined(COBALT_MEDIA_SOURCE_2016)

// The HTMLMediaElement is the base of HTMLAudioElement and HTMLVideoElement.
//   https://www.w3.org/TR/html5/embedded-content-0.html#media-element
class HTMLMediaElement : public HTMLElement, private WebMediaPlayerClient {
 public:
  HTMLMediaElement(Document* document, base::Token tag_name);
  ~HTMLMediaElement() OVERRIDE;

  // Web API: HTMLMediaElement
  //
  // Error state
  scoped_refptr<MediaError> error() const;

  // Network state
  std::string src() const;
  void set_src(const std::string& src);
  const std::string& current_src() const { return current_src_; }

  enum NetworkState {
    kNetworkEmpty,
    kNetworkIdle,
    kNetworkLoading,
    kNetworkNoSource
  };
  uint16_t network_state() const;

  scoped_refptr<TimeRanges> buffered() const;
  void Load();
  std::string CanPlayType(const std::string& mimeType);
  std::string CanPlayType(const std::string& mimeType,
                          const std::string& key_system);

#if defined(COBALT_MEDIA_SOURCE_2016)
  const EventListenerScriptValue* onencrypted() const;
  void set_onencrypted(const EventListenerScriptValue& event_listener);

  const scoped_refptr<eme::MediaKeys>& media_keys() const {
    return media_keys_;
  }
  typedef script::ScriptValue<script::Promise<void> > VoidPromiseValue;
  scoped_ptr<VoidPromiseValue> SetMediaKeys(
      const scoped_refptr<eme::MediaKeys>& media_keys);
#else   // defined(COBALT_MEDIA_SOURCE_2016)
  void GenerateKeyRequest(
      const std::string& key_system,
      const base::optional<scoped_refptr<Uint8Array> >& init_data,
      script::ExceptionState* exception_state);
  void AddKey(const std::string& key_system,
              const scoped_refptr<const Uint8Array>& key,
              const base::optional<scoped_refptr<Uint8Array> >& init_data,
              const base::optional<std::string>& session_id,
              script::ExceptionState* exception_state);
  void CancelKeyRequest(const std::string& key_system,
                        const base::optional<std::string>& session_id,
                        script::ExceptionState* exception_state);
#endif  // defined(COBALT_MEDIA_SOURCE_2016)

  // Ready state
  enum ReadyState {
    kHaveNothing = WebMediaPlayer::kReadyStateHaveNothing,
    kHaveMetadata = WebMediaPlayer::kReadyStateHaveMetadata,
    kHaveCurrentData = WebMediaPlayer::kReadyStateHaveCurrentData,
    kHaveFutureData = WebMediaPlayer::kReadyStateHaveFutureData,
    kHaveEnoughData = WebMediaPlayer::kReadyStateHaveEnoughData,
  };

  uint16_t ready_state() const;
  bool seeking() const;

  // Playback state
  float current_time(script::ExceptionState* exception_state) const;
  void set_current_time(float time, script::ExceptionState* exception_state);
  float duration() const;
  bool paused() const;
  float default_playback_rate() const;
  void set_default_playback_rate(float rate);
  float playback_rate() const;
  void set_playback_rate(float rate);
  const scoped_refptr<TimeRanges>& played();
  scoped_refptr<TimeRanges> seekable() const;
  bool ended() const;
  bool autoplay() const;
  void set_autoplay(bool autoplay);
  bool loop() const;
  void set_loop(bool loop);
  void Play();
  void Pause();

  // Controls
  bool controls() const;
  void set_controls(bool controls);
  float volume(script::ExceptionState* exception_state) const;
  void set_volume(float volume, script::ExceptionState* exception_state);
  bool muted() const;
  void set_muted(bool muted);

  // Custom, not in any spec
  //
  // From Node
  void OnInsertedIntoDocument() OVERRIDE;

#if defined(COBALT_MEDIA_SOURCE_2016)
  // Called by MediaSource
  void DurationChanged(double duration, bool request_seek);
#endif  // defined(COBALT_MEDIA_SOURCE_2016)

  // Let other objects add event to the EventQueue of HTMLMediaElement.  This
  // function won't modify the target of the |event| passed in.
  void ScheduleEvent(const scoped_refptr<Event>& event);

  DEFINE_WRAPPABLE_TYPE(HTMLMediaElement);

 protected:
  WebMediaPlayer* player() { return player_.get(); }
  const WebMediaPlayer* player() const { return player_.get(); }

 private:
  static const char kMediaSourceUrlProtocol[];
  static const double kMaxTimeupdateEventFrequency;

  // Loading
  void CreateMediaPlayer();
  void ScheduleLoad();
  void PrepareForLoad();
  void LoadInternal();
  void LoadResource(const GURL& initial_url, const std::string& content_type,
                    const std::string& key_system);
  void ClearMediaPlayer();
  void NoneSupported();
  void MediaLoadingFailed(WebMediaPlayer::NetworkState error);

  // Timers
  void OnLoadTimer();
  void OnProgressEventTimer();
  void OnPlaybackProgressTimer();
  void StartPlaybackProgressTimer();
  void StartProgressEventTimer();
  void StopPeriodicTimers();

  // Events
  void ScheduleTimeupdateEvent(bool periodic_event);
  void ScheduleOwnEvent(base::Token event_name);
  void CancelPendingEventsAndCallbacks();
  bool ProcessingMediaPlayerCallback() const {
    return processing_media_player_callback_ > 0;
  }
  void BeginProcessingMediaPlayerCallback() {
    ++processing_media_player_callback_;
  }
  void EndProcessingMediaPlayerCallback() {
    DCHECK(processing_media_player_callback_);
    --processing_media_player_callback_;
  }

  // States
  void SetReadyState(WebMediaPlayer::ReadyState state);
  void SetNetworkState(WebMediaPlayer::NetworkState state);
  void ChangeNetworkStateFromLoadingToIdle();

  // Playback
  void Seek(float time);
  void FinishSeek();

  void AddPlayedRange(float start, float end);

  void UpdateVolume();
  void UpdatePlayState();
  bool PotentiallyPlaying() const;
  bool EndedPlayback() const;
  bool StoppedDueToErrors() const;
  bool CouldPlayIfEnoughData() const;

  void ConfigureMediaControls();

  // Error report
  void MediaEngineError(scoped_refptr<MediaError> error);

  // WebMediaPlayerClient methods
  void NetworkStateChanged() OVERRIDE;
  void ReadyStateChanged() OVERRIDE;
  void TimeChanged(bool eos_played) OVERRIDE;
  void DurationChanged() OVERRIDE;
  void OutputModeChanged() OVERRIDE;
  void PlaybackStateChanged() OVERRIDE;
  void SawUnsupportedTracks() OVERRIDE;
  float Volume() const OVERRIDE;
#if defined(COBALT_MEDIA_SOURCE_2016)
  void SourceOpened(ChunkDemuxer* chunk_demuxer) OVERRIDE;
#else   // defined(COBALT_MEDIA_SOURCE_2016)
  void SourceOpened() OVERRIDE;
#endif  // defined(COBALT_MEDIA_SOURCE_2016)
  std::string SourceURL() const OVERRIDE;
  bool PreferDecodeToTexture() OVERRIDE;
#if defined(COBALT_MEDIA_SOURCE_2016)
  void EncryptedMediaInitDataEncountered(
      media::EmeInitDataType init_data_type, const unsigned char* init_data,
      unsigned int init_data_length) OVERRIDE;
#else   // defined(COBALT_MEDIA_SOURCE_2016)
  void KeyAdded(const std::string& key_system,
                const std::string& session_id) OVERRIDE;
  void KeyError(const std::string& key_system, const std::string& session_id,
                MediaKeyErrorCode error_code, uint16 system_code) OVERRIDE;
  void KeyMessage(const std::string& key_system, const std::string& session_id,
                  const unsigned char* message, unsigned int message_length,
                  const std::string& default_url) OVERRIDE;
  void KeyNeeded(const std::string& key_system, const std::string& session_id,
                 const unsigned char* init_data,
                 unsigned int init_data_length) OVERRIDE;
#endif  // !defined(COBALT_MEDIA_SOURCE_2016)
  void ClearMediaSource();
#if !defined(COBALT_MEDIA_SOURCE_2016)
  void SetSourceState(MediaSourceReadyState ready_state);
#endif  // !defined(COBALT_MEDIA_SOURCE_2016)

  scoped_ptr<WebMediaPlayer> player_;

  std::string current_src_;
  // Loading state.
  enum LoadState { kWaitingForSource, kLoadingFromSrcAttr };
  LoadState load_state_;

  EventQueue event_queue_;

  base::OneShotTimer<HTMLMediaElement> load_timer_;
  base::RepeatingTimer<HTMLMediaElement> progress_event_timer_;
  base::RepeatingTimer<HTMLMediaElement> playback_progress_timer_;
  scoped_refptr<TimeRanges> played_time_ranges_;
  float playback_rate_;
  float default_playback_rate_;
  NetworkState network_state_;
  WebMediaPlayer::ReadyState ready_state_;
  WebMediaPlayer::ReadyState ready_state_maximum_;

  float volume_;
  float last_seek_time_;
  double previous_progress_time_;

  double duration_;

  bool playing_;
  bool have_fired_loaded_data_;
  bool autoplaying_;
  bool muted_;
  bool paused_;
  bool seeking_;
  bool loop_;
  bool controls_;

  // The last time a timeupdate event was sent (wall clock).
  double last_time_update_event_wall_time_;
  // The last time a timeupdate event was sent in movie time.
  double last_time_update_event_movie_time_;

  // Counter incremented while processing a callback from the media player, so
  // we can avoid calling the low level player recursively.
  int processing_media_player_callback_;

  GURL media_source_url_;
  scoped_refptr<MediaSource> media_source_;

  bool pending_load_;

  // Data has not been loaded since sending a "stalled" event.
  bool sent_stalled_event_;
  // Time has not changed since sending an "ended" event.
  bool sent_end_event_;

  scoped_refptr<MediaError> error_;

  // Helper object to reduce the image capacity while a video is playing.
  base::optional<loader::image::ReducedCacheCapacityManager::Request>
      reduced_image_cache_capacity_request_;

#if defined(COBALT_MEDIA_SOURCE_2016)
  scoped_refptr<eme::MediaKeys> media_keys_;
#endif  // defined(COBALT_MEDIA_SOURCE_2016)

  DISALLOW_COPY_AND_ASSIGN(HTMLMediaElement);
};

}  // namespace dom
}  // namespace cobalt

#endif  // COBALT_DOM_HTML_MEDIA_ELEMENT_H_