third_party/WebKit/Source/core/html/track/CueTimeline.h

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CueTimeline_h
   6 #define CueTimeline_h
   7
   8 #include "core/html/track/TextTrackCue.h"
   9 #include "core/html/track/vtt/VTTCue.h"
  10 #include "platform/PODIntervalTree.h"
  11 #include "platform/heap/Handle.h"
  12 #include "wtf/Vector.h"
  13
  14 namespace blink {
  15
  16 class HTMLMediaElement;
  17 class TextTrackCueList;
  18
  19 // TODO(Oilpan): This needs to be PODIntervalTree<double, Member<TextTrackCue>>.
  20 // However, it is not easy to move PODIntervalTree to the heap (for a C++-template
  21 // reason) so we leave it as a raw pointer at the moment. This is safe
  22 // because CueTimeline and TextTrackCue are guaranteed to die at the same time
  23 // when the owner HTMLMediaElement dies. Thus the raw TextTrackCue* cannot
  24 // become stale pointers.
  25 typedef PODIntervalTree<double, TextTrackCue*> CueIntervalTree;
  26 typedef CueIntervalTree::IntervalType CueInterval;
  27 typedef Vector<CueInterval> CueList;
  28
  29 // This class manages the timeline and rendering updates of cues associated
  30 // with TextTracks. Owned by a HTMLMediaElement.
  31 class CueTimeline final : public NoBaseWillBeGarbageCollectedFinalized<CueTimeline> {
  32     WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED(CueTimeline);
  33 public:
  34     CueTimeline(HTMLMediaElement&);
  35
  36     void addCues(TextTrack*, const TextTrackCueList*);
  37     void addCue(TextTrack*, PassRefPtrWillBeRawPtr<TextTrackCue>);
  38     void removeCues(TextTrack*, const TextTrackCueList*);
  39     void removeCue(TextTrack*, PassRefPtrWillBeRawPtr<TextTrackCue>);
  40
  41     void hideCues(TextTrack*, const TextTrackCueList*);
  42
  43     void updateActiveCues(double);
  44
  45     bool ignoreUpdateRequests() const { return m_ignoreUpdate > 0; }
  46     void beginIgnoringUpdateRequests();
  47     void endIgnoringUpdateRequests();
  48
  49     const CueList& currentlyActiveCues() const { return m_currentlyActiveCues; }
  50
  51     DECLARE_TRACE();
  52
  53 private:
  54     HTMLMediaElement& mediaElement() const { return *m_mediaElement; }
  55
  56     void addCueInternal(PassRefPtrWillBeRawPtr<TextTrackCue>);
  57     void removeCueInternal(PassRefPtrWillBeRawPtr<TextTrackCue>);
  58
  59     RawPtrWillBeMember<HTMLMediaElement> m_mediaElement;
  60
  61     CueIntervalTree m_cueTree;
  62
  63     CueList m_currentlyActiveCues;
  64     double m_lastUpdateTime;
  65
  66     int m_ignoreUpdate;
  67 };
  68
  69 class TrackDisplayUpdateScope {
  70     STACK_ALLOCATED();
  71 public:
  72     TrackDisplayUpdateScope(CueTimeline& cueTimeline)
  73     {
  74         m_cueTimeline = &cueTimeline;
  75         m_cueTimeline->beginIgnoringUpdateRequests();
  76     }
  77     ~TrackDisplayUpdateScope()
  78     {
  79         ASSERT(m_cueTimeline);
  80         m_cueTimeline->endIgnoringUpdateRequests();
  81     }
  82
  83 private:
  84     RawPtrWillBeMember<CueTimeline> m_cueTimeline;
  85 };
  86
  87 #ifndef NDEBUG
  88 // Template specializations required by PodIntervalTree in debug mode.
  89 template <>
  90 struct ValueToString<double> {
  91     static String string(const double value)
  92     {
  93         return String::number(value);
  94     }
  95 };
  96
  97 template <>
  98 struct ValueToString<TextTrackCue*> {
  99     static String string(TextTrackCue* const& cue)
 100     {
 101         return cue->toString();
 102     }
 103 };
 104 #endif
 105
 106 } // namespace blink
 107
 108 #endif // CueTimeline_h