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 "mozilla/TimeStamp.h"
  15 #include "nsCycleCollectionParticipant.h"
  16 #include "nsIDocumentActivity.h"
  17 #include "nsWrapperCache.h"
  18
  19 class nsPIDOMWindowInner;
  20
  21 namespace mozilla {
  22 class ErrorResult;
  23
  24 namespace dom {
  25
  26 class Document;
  27 class MediaMetadata;
  28
  29 // https://w3c.github.io/mediasession/#position-state
  30 struct PositionState {
  31   PositionState() = default;
  32   PositionState(double aDuration, double aPlaybackRate,
  33                 double aLastReportedTime, TimeStamp aPositionUpdatedTime)
  34       : mDuration(aDuration),
  35         mPlaybackRate(aPlaybackRate),
  36         mLastReportedPlaybackPosition(aLastReportedTime),
  37         mPositionUpdatedTime(aPositionUpdatedTime) {}
  38
  39   double mDuration = 0.0;
  40   double mPlaybackRate = 0.0;
  41   double mLastReportedPlaybackPosition = 0.0;
  42   TimeStamp mPositionUpdatedTime;
  43
  44   // Returns the playback position in seconds (from 0 to mDuration)
  45   // at the current time (aNow).
  46   // https://w3c.github.io/mediasession/#current-playback-position
  47   double CurrentPlaybackPosition(TimeStamp aNow = TimeStamp::Now()) const;
  48 };
  49
  50 class MediaSession final : public nsIDocumentActivity, public nsWrapperCache {
  51  public:
  52   // Ref counting and cycle collection
  53   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  54   NS_DECL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS(MediaSession)
  55   NS_DECL_NSIDOCUMENTACTIVITY
  56
  57   explicit MediaSession(nsPIDOMWindowInner* aParent);
  58
  59   // WebIDL methods
  60   nsPIDOMWindowInner* GetParentObject() const;
  61
  62   JSObject* WrapObject(JSContext* aCx,
  63                        JS::Handle<JSObject*> aGivenProto) override;
  64
  65   MediaMetadata* GetMetadata() const;
  66
  67   void SetMetadata(MediaMetadata* aMetadata);
  68
  69   void SetPlaybackState(const MediaSessionPlaybackState& aPlaybackState);
  70
  71   MediaSessionPlaybackState PlaybackState() const;
  72
  73   void SetActionHandler(MediaSessionAction aAction,
  74                         MediaSessionActionHandler* aHandler);
  75
  76   void SetPositionState(const MediaPositionState& aState, ErrorResult& aRv);
  77
  78   bool IsSupportedAction(MediaSessionAction aAction) const;
  79
  80   // Use this method to trigger media session action handler asynchronously.
  81   void NotifyHandler(const MediaSessionActionDetails& aDetails);
  82
  83   void Shutdown();
  84
  85   // `MediaStatusManager` would determine which media session is an active media
  86   // session and update it from the chrome process. This active session is not
  87   // 100% equal to the active media session in the spec, which is a globally
  88   // active media session *among all tabs*. The active session here is *among
  89   // different windows but in same tab*, so each tab can have at most one
  90   // active media session.
  91   bool IsActive() const;
  92
  93  private:
  94   // When the document which media session belongs to is going to be destroyed,
  95   // or is in the bfcache, then the session would be inactive. Otherwise, it's
  96   // active all the time.
  97   enum class SessionDocStatus : bool {
  98     eInactive = false,
  99     eActive = true,
 100   };
 101   void SetMediaSessionDocStatus(SessionDocStatus aState);
 102
 103   // These methods are used to propagate media session's status to the chrome
 104   // process.
 105   void NotifyMediaSessionDocStatus(SessionDocStatus aState);
 106   void NotifyMediaSessionAttributes();
 107   void NotifyPlaybackStateUpdated();
 108   void NotifyMetadataUpdated();
 109   void NotifyEnableSupportedAction(MediaSessionAction aAction);
 110   void NotifyDisableSupportedAction(MediaSessionAction aAction);
 111   void NotifyPositionStateChanged();
 112
 113   void DispatchNotifyHandler(const MediaSessionActionDetails& aDetails);
 114
 115   MediaSessionActionHandler* GetActionHandler(MediaSessionAction aAction) const;
 116
 117   ~MediaSession() = default;
 118
 119   nsCOMPtr<nsPIDOMWindowInner> mParent;
 120
 121   RefPtr<MediaMetadata> mMediaMetadata;
 122
 123   EnumeratedArray<MediaSessionAction, RefPtr<MediaSessionActionHandler>>
 124       mActionHandlers;
 125
 126   // This is used as is a hint for the user agent to determine whether the
 127   // browsing context is playing or paused.
 128   // https://w3c.github.io/mediasession/#declared-playback-state
 129   MediaSessionPlaybackState mDeclaredPlaybackState =
 130       MediaSessionPlaybackState::None;
 131
 132   Maybe<PositionState> mPositionState;
 133   RefPtr<Document> mDoc;
 134   SessionDocStatus mSessionDocState = SessionDocStatus::eInactive;
 135 };
 136
 137 }  // namespace dom
 138 }  // namespace mozilla
 139
 140 #endif  // mozilla_dom_MediaSession_h