MediaController.h - mozsearch

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this file,

 * You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef DOM_MEDIA_MEDIACONTROL_MEDIACONTROLLER_H_

#define DOM_MEDIA_MEDIACONTROL_MEDIACONTROLLER_H_

#include "MediaEventSource.h"

#include "MediaPlaybackStatus.h"

#include "MediaStatusManager.h"

#include "mozilla/DOMEventTargetHelper.h"

#include "mozilla/dom/MediaControllerBinding.h"

#include "mozilla/dom/MediaSession.h"

#include "mozilla/LinkedList.h"

#include "nsISupportsImpl.h"

#include "nsITimer.h"

namespace mozilla::dom {

class BrowsingContext;

/**

 * IMediaController is an interface which includes control related methods and

 * methods used to know its playback state.

*/

class IMediaController {

 public:

  NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING

  // Focus the window currently playing media.

  virtual void Focus() = 0;

  virtual void Play() = 0;

  virtual void Pause() = 0;

  virtual void Stop() = 0;

  virtual void PrevTrack() = 0;

  virtual void NextTrack() = 0;

  virtual void SeekBackward() = 0;

  virtual void SeekForward() = 0;

  virtual void SkipAd() = 0;

  virtual void SeekTo(double aSeekTime, bool aFastSeek) = 0;

  // Return the ID of the top level browsing context within a tab.

  virtual uint64_t Id() const = 0;

  virtual bool IsAudible() const = 0;

  virtual bool IsPlaying() const = 0;

  virtual bool IsActive() const = 0;

};

/**

 * MediaController is a class, which is used to control all media within a tab.

 * It can only be used in Chrome process and the controlled media are usually

 * in the content process (unless we disable e10s).

 * Each tab would have only one media controller, they are 1-1 corresponding

 * relationship, we use tab's top-level browsing context ID to initialize the

 * controller and use that as its ID.

 * The controller would be activated when its controlled media starts and

 * becomes audible. After the controller is activated, then we can use its

 * controlling methods, such as `Play()`, `Pause()` to control the media within

 * the tab.

 * If there is at least one controlled media playing in the tab, then we would

 * say the controller is `playing`. If there is at least one controlled media is

 * playing and audible, then we would say the controller is `audible`.

 * Note that, if we don't enable audio competition, then we might have multiple

 * tabs playing media at the same time, we can use the ID to query the specific

 * controller from `MediaControlService`.

*/

class MediaController final : public DOMEventTargetHelper,

                              public IMediaController,

                              public LinkedListElement<RefPtr<MediaController>>,

                              public MediaStatusManager,

                              public nsITimerCallback,

                              public nsINamed {

 public:

  NS_DECL_ISUPPORTS_INHERITED

  NS_DECL_NSITIMERCALLBACK

  NS_DECL_NSINAMED

  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_INHERITED(MediaController,

                                                         DOMEventTargetHelper)

  explicit MediaController(uint64_t aBrowsingContextId);

  // WebIDL methods

  nsISupports* GetParentObject() const;

  JSObject* WrapObject(JSContext* aCx,

                       JS::Handle<JSObject*> aGivenProto) override;

  void GetSupportedKeys(nsTArray<MediaControlKey>& aRetVal) const;

  void GetMetadata(MediaMetadataInit& aMetadata, ErrorResult& aRv);

  IMPL_EVENT_HANDLER(activated);

  IMPL_EVENT_HANDLER(deactivated);

  IMPL_EVENT_HANDLER(metadatachange);

  IMPL_EVENT_HANDLER(supportedkeyschange);

  IMPL_EVENT_HANDLER(playbackstatechange);

  IMPL_EVENT_HANDLER(positionstatechange);

  // IMediaController's methods

  void Focus() override;

  void Play() override;

  void Pause() override;

  void Stop() override;

  void PrevTrack() override;

  void NextTrack() override;

  void SeekBackward() override;

  void SeekForward() override;

  void SkipAd() override;

  void SeekTo(double aSeekTime, bool aFastSeek) override;

  uint64_t Id() const override;

  bool IsAudible() const override;

  bool IsPlaying() const override;

  bool IsActive() const override;

  // IMediaInfoUpdater's methods

  void NotifyMediaPlaybackChanged(uint64_t aBrowsingContextId,

                                  MediaPlaybackState aState) override;

  void NotifyMediaAudibleChanged(uint64_t aBrowsingContextId,

                                 MediaAudibleState aState) override;

  void SetIsInPictureInPictureMode(uint64_t aBrowsingContextId,

                                   bool aIsInPictureInPictureMode) override;

  void NotifyMediaFullScreenState(uint64_t aBrowsingContextId,

                                  bool aIsInFullScreen) override;

  // Calling this method explicitly would mark this controller as deprecated,

  // then calling any its method won't take any effect.

  void Shutdown();

  // This event would be notified media controller's supported media keys

  // change.

  MediaEventSource<nsTArray<MediaControlKey>>& SupportedKeysChangedEvent() {

    return mSupportedKeysChangedEvent;

  MediaEventSource<bool>& FullScreenChangedEvent() {

    return mFullScreenChangedEvent;

  MediaEventSource<bool>& PictureInPictureModeChangedEvent() {

    return mPictureInPictureModeChangedEvent;

  CopyableTArray<MediaControlKey> GetSupportedMediaKeys() const;

  bool IsBeingUsedInPIPModeOrFullscreen() const;

  // These methods are used to select/unselect the media controller as a main

  // controller.

  void Select() const;

  void Unselect() const;

 private:

  ~MediaController();

  void HandleActualPlaybackStateChanged();

  void UpdateMediaControlActionToContentMediaIfNeeded(

      const MediaControlAction& aAction);

  void HandleSupportedMediaSessionActionsChanged(

      const nsTArray<MediaSessionAction>& aSupportedAction);

  void HandlePositionStateChanged(const Maybe<PositionState>& aState);

  void HandleMetadataChanged(const MediaMetadataBase& aMetadata);

  // This would register controller to the media control service that takes a

  // responsibility to manage all active controllers.

  void Activate();

  // This would unregister controller from the media control service.

  void Deactivate();

  void UpdateActivatedStateIfNeeded();

  bool ShouldActivateController() const;

  bool ShouldDeactivateController() const;

  void UpdateDeactivationTimerIfNeeded();

  void DispatchAsyncEvent(const nsAString& aName);

  void DispatchAsyncEvent(already_AddRefed<Event> aEvent);

  bool IsMainController() const;

  void ForceToBecomeMainControllerIfNeeded();

  bool ShouldRequestForMainController() const;

  bool ShouldPropagateActionToAllContexts(

      const MediaControlAction& aAction) const;

  bool mIsActive = false;

  bool mShutdown = false;

  bool mIsInPictureInPictureMode = false;

  bool mIsInFullScreenMode = false;

  // We would monitor the change of media session actions and convert them to

  // the media keys, then determine the supported media keys.

  MediaEventListener mSupportedActionsChangedListener;

  MediaEventProducer<nsTArray<MediaControlKey>> mSupportedKeysChangedEvent;

  MediaEventListener mPlaybackChangedListener;

  MediaEventListener mPositionStateChangedListener;

  MediaEventListener mMetadataChangedListener;

  MediaEventProducer<bool> mFullScreenChangedEvent;

  MediaEventProducer<bool> mPictureInPictureModeChangedEvent;

  // Use copyable array so that we can use the result as a parameter for the

  // media event.

  CopyableTArray<MediaControlKey> mSupportedKeys;

  // Timer to deactivate the controller if the time of being paused exceeds the

  // threshold of time.

  nsCOMPtr<nsITimer> mDeactivationTimer;

};

}  // namespace mozilla::dom

#endif