dom/media/mediasession/MediaSession.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim:set ts=2 sw=2 sts=2 et cindent: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_dom_MediaSession_h
   8 #define mozilla_dom_MediaSession_h
   9
  10 #include "js/TypeDecls.h"
  11 #include "mozilla/Attributes.h"
  12 #include "mozilla/dom/MediaSessionBinding.h"
  13 #include "mozilla/EnumeratedArray.h"
  14 #include "nsCycleCollectionParticipant.h"
  15 #include "nsIDocumentActivity.h"
  16 #include "nsWrapperCache.h"
  17
  18 class nsPIDOMWindowInner;
  19
  20 namespace mozilla {
  21 class ErrorResult;
  22
  23 namespace dom {
  24
  25 class Document;
  26 class MediaMetadata;
  27
  28 // https://w3c.github.io/mediasession/#position-state
  29 struct PositionState {
  30   PositionState() = default;
  31   PositionState(double aDuration, double aPlaybackRate,
  32                 double aLastReportedTime)
  33       : mDuration(aDuration),
  34         mPlaybackRate(aPlaybackRate),
  35         mLastReportedPlaybackPosition(aLastReportedTime) {}
  36   double mDuration;
  37   double mPlaybackRate;
  38   double mLastReportedPlaybackPosition;
  39 };
  40
  41 class MediaSession final : public nsIDocumentActivity, public nsWrapperCache {
  42  public:
  43   // Ref counting and cycle collection
  44   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  45   NS_DECL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS(MediaSession)
  46   NS_DECL_NSIDOCUMENTACTIVITY
  47
  48   explicit MediaSession(nsPIDOMWindowInner* aParent);
  49
  50   // WebIDL methods
  51   nsPIDOMWindowInner* GetParentObject() const;
  52
  53   JSObject* WrapObject(JSContext* aCx,
  54                        JS::Handle<JSObject*> aGivenProto) override;
  55
  56   MediaMetadata* GetMetadata() const;
  57
  58   void SetMetadata(MediaMetadata* aMetadata);
  59
  60   void SetPlaybackState(const MediaSessionPlaybackState& aPlaybackState);
  61
  62   MediaSessionPlaybackState PlaybackState() const;
  63
  64   void SetActionHandler(MediaSessionAction aAction,
  65                         MediaSessionActionHandler* aHandler);
  66
  67   void SetPositionState(const MediaPositionState& aState, ErrorResult& aRv);
  68
  69   bool IsSupportedAction(MediaSessionAction aAction) const;
  70
  71   // Use this method to trigger media session action handler asynchronously.
  72   void NotifyHandler(const MediaSessionActionDetails& aDetails);
  73
  74   void Shutdown();
  75
  76   // `MediaStatusManager` would determine which media session is an active media
  77   // session and update it from the chrome process. This active session is not
  78   // 100% equal to the active media session in the spec, which is a globally
  79   // active media session *among all tabs*. The active session here is *among
  80   // different windows but in same tab*, so each tab can have at most one
  81   // active media session.
  82   bool IsActive() const;
  83
  84  private:
  85   // When the document which media session belongs to is going to be destroyed,
  86   // or is in the bfcache, then the session would be inactive. Otherwise, it's
  87   // active all the time.
  88   enum class SessionDocStatus : bool {
  89     eInactive = false,
  90     eActive = true,
  91   };
  92   void SetMediaSessionDocStatus(SessionDocStatus aState);
  93
  94   // These methods are used to propagate media session's status to the chrome
  95   // process.
  96   void NotifyMediaSessionDocStatus(SessionDocStatus aState);
  97   void NotifyMediaSessionAttributes();
  98   void NotifyPlaybackStateUpdated();
  99   void NotifyMetadataUpdated();
 100   void NotifyEnableSupportedAction(MediaSessionAction aAction);
 101   void NotifyDisableSupportedAction(MediaSessionAction aAction);
 102   void NotifyPositionStateChanged();
 103
 104   void DispatchNotifyHandler(const MediaSessionActionDetails& aDetails);
 105
 106   MediaSessionActionHandler* GetActionHandler(MediaSessionAction aAction) const;
 107
 108   ~MediaSession() = default;
 109
 110   nsCOMPtr<nsPIDOMWindowInner> mParent;
 111
 112   RefPtr<MediaMetadata> mMediaMetadata;
 113
 114   EnumeratedArray<MediaSessionAction, MediaSessionAction::EndGuard_,
 115                   RefPtr<MediaSessionActionHandler>>
 116       mActionHandlers;
 117
 118   // This is used as is a hint for the user agent to determine whether the
 119   // browsing context is playing or paused.
 120   // https://w3c.github.io/mediasession/#declared-playback-state
 121   MediaSessionPlaybackState mDeclaredPlaybackState =
 122       MediaSessionPlaybackState::None;
 123
 124   Maybe<PositionState> mPositionState;
 125   RefPtr<Document> mDoc;
 126   SessionDocStatus mSessionDocState = SessionDocStatus::eInactive;
 127 };
 128
 129 }  // namespace dom
 130 }  // namespace mozilla
 131
 132 #endif  // mozilla_dom_MediaSession_h