1 files changed, 79 insertions, 0 deletions
diff --git a/dom/media/MediaTrack.h b/dom/media/MediaTrack.h
new file mode 100644
index 0000000000..8b030c8562
--- /dev/null
+++ b/dom/media/MediaTrack.h
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 et tw=78: */
+/* 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_MediaTrack_h
+#define mozilla_dom_MediaTrack_h
+
+#include "mozilla/DOMEventTargetHelper.h"
+
+namespace mozilla::dom {
+
+class MediaTrackList;
+class VideoTrack;
+class AudioTrack;
+
+/**
+ * Base class of AudioTrack and VideoTrack. The AudioTrack and VideoTrack
+ * objects represent specific tracks of a media resource. Each track has aspects
+ * of an identifier, category, label, and language, even if a track is removed
+ * from its corresponding track list, those aspects do not change.
+ *
+ * When fetching the media resource, an audio/video track is created if the
+ * media resource is found to have an audio/video track. When the UA has learned
+ * that an audio/video track has ended, this audio/video track will be removed
+ * from its corresponding track list.
+ *
+ * Although AudioTrack and VideoTrack are not EventTargets, TextTrack is, and
+ * TextTrack inherits from MediaTrack as well (or is going to).
+ */
+class MediaTrack : public DOMEventTargetHelper {
+ public:
+  MediaTrack(nsIGlobalObject* aOwnerGlobal, const nsAString& aId,
+             const nsAString& aKind, const nsAString& aLabel,
+             const nsAString& aLanguage);
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(dom::MediaTrack,
+                                           DOMEventTargetHelper)
+
+  enum {
+    DEFAULT = 0,
+    FIRE_NO_EVENTS = 1 << 0,
+  };
+  // The default behavior of enabling an audio track or selecting a video track
+  // fires a change event and notifies its media resource about the changes.
+  // It should not fire any events when fetching media resource.
+  virtual void SetEnabledInternal(bool aEnabled, int aFlags) = 0;
+
+  virtual AudioTrack* AsAudioTrack() { return nullptr; }
+
+  virtual VideoTrack* AsVideoTrack() { return nullptr; }
+
+  const nsString& GetId() const { return mId; }
+
+  // WebIDL
+  void GetId(nsAString& aId) const { aId = mId; }
+  void GetKind(nsAString& aKind) const { aKind = mKind; }
+  void GetLabel(nsAString& aLabel) const { aLabel = mLabel; }
+  void GetLanguage(nsAString& aLanguage) const { aLanguage = mLanguage; }
+
+  friend class MediaTrackList;
+
+ protected:
+  virtual ~MediaTrack();
+
+  void SetTrackList(MediaTrackList* aList);
+
+  RefPtr<MediaTrackList> mList;
+  nsString mId;
+  nsString mKind;
+  nsString mLabel;
+  nsString mLanguage;
+};
+
+}  // namespace mozilla::dom
+
+#endif  // mozilla_dom_MediaTrack_h