1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* vim:set ts=2 sw=2 et tw=78: */
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_MediaTrack_h
8 #define mozilla_dom_MediaTrack_h
9 
10 #include "mozilla/DOMEventTargetHelper.h"
11 
12 namespace mozilla {
13 namespace dom {
14 
15 class MediaTrackList;
16 class VideoTrack;
17 class AudioTrack;
18 
19 /**
20  * Base class of AudioTrack and VideoTrack. The AudioTrack and VideoTrack
21  * objects represent specific tracks of a media resource. Each track has aspects
22  * of an identifier, category, label, and language, even if a track is removed
23  * from its corresponding track list, those aspects do not change.
24  *
25  * When fetching the media resource, an audio/video track is created if the
26  * media resource is found to have an audio/video track. When the UA has learned
27  * that an audio/video track has ended, this audio/video track will be removed
28  * from its corresponding track list.
29  *
30  * Although AudioTrack and VideoTrack are not EventTargets, TextTrack is, and
31  * TextTrack inherits from MediaTrack as well (or is going to).
32  */
33 class MediaTrack : public DOMEventTargetHelper {
34  public:
35   MediaTrack(nsIGlobalObject* aOwnerGlobal, const nsAString& aId,
36              const nsAString& aKind, const nsAString& aLabel,
37              const nsAString& aLanguage);
38 
39   NS_DECL_ISUPPORTS_INHERITED
40   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(dom::MediaTrack,
41                                            DOMEventTargetHelper)
42 
43   enum {
44     DEFAULT = 0,
45     FIRE_NO_EVENTS = 1 << 0,
46   };
47   // The default behavior of enabling an audio track or selecting a video track
48   // fires a change event and notifies its media resource about the changes.
49   // It should not fire any events when fetching media resource.
50   virtual void SetEnabledInternal(bool aEnabled, int aFlags) = 0;
51 
AsAudioTrack()52   virtual AudioTrack* AsAudioTrack() { return nullptr; }
53 
AsVideoTrack()54   virtual VideoTrack* AsVideoTrack() { return nullptr; }
55 
GetId()56   const nsString& GetId() const { return mId; }
57 
58   // WebIDL
GetId(nsAString & aId)59   void GetId(nsAString& aId) const { aId = mId; }
GetKind(nsAString & aKind)60   void GetKind(nsAString& aKind) const { aKind = mKind; }
GetLabel(nsAString & aLabel)61   void GetLabel(nsAString& aLabel) const { aLabel = mLabel; }
GetLanguage(nsAString & aLanguage)62   void GetLanguage(nsAString& aLanguage) const { aLanguage = mLanguage; }
63 
64   friend class MediaTrackList;
65 
66  protected:
67   virtual ~MediaTrack();
68 
69   void SetTrackList(MediaTrackList* aList);
70 
71   RefPtr<MediaTrackList> mList;
72   nsString mId;
73   nsString mKind;
74   nsString mLabel;
75   nsString mLanguage;
76 };
77 
78 }  // namespace dom
79 }  // namespace mozilla
80 
81 #endif  // mozilla_dom_MediaTrack_h
82