1 files changed, 132 insertions, 0 deletions
diff --git a/dom/media/mediasession/MediaSession.h b/dom/media/mediasession/MediaSession.h
new file mode 100644
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+++ b/dom/media/mediasession/MediaSession.h
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* 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 mozilla_dom_MediaSession_h
+#define mozilla_dom_MediaSession_h
+
+#include "js/TypeDecls.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/dom/MediaSessionBinding.h"
+#include "mozilla/EnumeratedArray.h"
+#include "nsCycleCollectionParticipant.h"
+#include "nsIDocumentActivity.h"
+#include "nsWrapperCache.h"
+
+class nsPIDOMWindowInner;
+
+namespace mozilla {
+class ErrorResult;
+
+namespace dom {
+
+class Document;
+class MediaMetadata;
+
+// https://w3c.github.io/mediasession/#position-state
+struct PositionState {
+  PositionState() = default;
+  PositionState(double aDuration, double aPlaybackRate,
+                double aLastReportedTime)
+      : mDuration(aDuration),
+        mPlaybackRate(aPlaybackRate),
+        mLastReportedPlaybackPosition(aLastReportedTime) {}
+  double mDuration;
+  double mPlaybackRate;
+  double mLastReportedPlaybackPosition;
+};
+
+class MediaSession final : public nsIDocumentActivity, public nsWrapperCache {
+ public:
+  // Ref counting and cycle collection
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS(MediaSession)
+  NS_DECL_NSIDOCUMENTACTIVITY
+
+  explicit MediaSession(nsPIDOMWindowInner* aParent);
+
+  // WebIDL methods
+  nsPIDOMWindowInner* GetParentObject() const;
+
+  JSObject* WrapObject(JSContext* aCx,
+                       JS::Handle<JSObject*> aGivenProto) override;
+
+  MediaMetadata* GetMetadata() const;
+
+  void SetMetadata(MediaMetadata* aMetadata);
+
+  void SetPlaybackState(const MediaSessionPlaybackState& aPlaybackState);
+
+  MediaSessionPlaybackState PlaybackState() const;
+
+  void SetActionHandler(MediaSessionAction aAction,
+                        MediaSessionActionHandler* aHandler);
+
+  void SetPositionState(const MediaPositionState& aState, ErrorResult& aRv);
+
+  bool IsSupportedAction(MediaSessionAction aAction) const;
+
+  // Use this method to trigger media session action handler asynchronously.
+  void NotifyHandler(const MediaSessionActionDetails& aDetails);
+
+  void Shutdown();
+
+  // `MediaStatusManager` would determine which media session is an active media
+  // session and update it from the chrome process. This active session is not
+  // 100% equal to the active media session in the spec, which is a globally
+  // active media session *among all tabs*. The active session here is *among
+  // different windows but in same tab*, so each tab can have at most one
+  // active media session.
+  bool IsActive() const;
+
+ private:
+  // When the document which media session belongs to is going to be destroyed,
+  // or is in the bfcache, then the session would be inactive. Otherwise, it's
+  // active all the time.
+  enum class SessionDocStatus : bool {
+    eInactive = false,
+    eActive = true,
+  };
+  void SetMediaSessionDocStatus(SessionDocStatus aState);
+
+  // These methods are used to propagate media session's status to the chrome
+  // process.
+  void NotifyMediaSessionDocStatus(SessionDocStatus aState);
+  void NotifyMediaSessionAttributes();
+  void NotifyPlaybackStateUpdated();
+  void NotifyMetadataUpdated();
+  void NotifyEnableSupportedAction(MediaSessionAction aAction);
+  void NotifyDisableSupportedAction(MediaSessionAction aAction);
+  void NotifyPositionStateChanged();
+
+  void DispatchNotifyHandler(const MediaSessionActionDetails& aDetails);
+
+  MediaSessionActionHandler* GetActionHandler(MediaSessionAction aAction) const;
+
+  ~MediaSession() = default;
+
+  nsCOMPtr<nsPIDOMWindowInner> mParent;
+
+  RefPtr<MediaMetadata> mMediaMetadata;
+
+  EnumeratedArray<MediaSessionAction, MediaSessionAction::EndGuard_,
+                  RefPtr<MediaSessionActionHandler>>
+      mActionHandlers;
+
+  // This is used as is a hint for the user agent to determine whether the
+  // browsing context is playing or paused.
+  // https://w3c.github.io/mediasession/#declared-playback-state
+  MediaSessionPlaybackState mDeclaredPlaybackState =
+      MediaSessionPlaybackState::None;
+
+  Maybe<PositionState> mPositionState;
+  RefPtr<Document> mDoc;
+  SessionDocStatus mSessionDocState = SessionDocStatus::eInactive;
+};
+
+}  // namespace dom
+}  // namespace mozilla
+
+#endif  // mozilla_dom_MediaSession_h