1// Copyright 2014 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 CONTENT_BROWSER_RENDERER_HOST_DISPLAY_LINK_MAC_H_
6#define CONTENT_BROWSER_RENDERER_HOST_DISPLAY_LINK_MAC_H_
7
8#include <QuartzCore/CVDisplayLink.h>
9#include <map>
10
11#include "base/lazy_instance.h"
12#include "base/mac/scoped_typeref.h"
13#include "base/memory/ref_counted.h"
14#include "base/synchronization/lock.h"
15#include "base/time/time.h"
16#include "base/timer/timer.h"
17
18namespace content {
19
20class DisplayLinkMac : public base::RefCounted<DisplayLinkMac> {
21 public:
22  static scoped_refptr<DisplayLinkMac> GetForDisplay(
23      CGDirectDisplayID display_id);
24
25  // Get vsync scheduling parameters.
26  bool GetVSyncParameters(
27      base::TimeTicks* timebase,
28      base::TimeDelta* interval);
29
30 private:
31  friend class base::RefCounted<DisplayLinkMac>;
32
33  DisplayLinkMac(
34      CGDirectDisplayID display_id,
35      base::ScopedTypeRef<CVDisplayLinkRef> display_link);
36  virtual ~DisplayLinkMac();
37
38  void StartOrContinueDisplayLink();
39  void StopDisplayLink();
40  void Tick(const CVTimeStamp* time);
41
42  static CVReturn DisplayLinkCallback(
43      CVDisplayLinkRef display_link,
44      const CVTimeStamp* now,
45      const CVTimeStamp* output_time,
46      CVOptionFlags flags_in,
47      CVOptionFlags* flags_out,
48      void* context);
49
50  // The display that this display link is attached to.
51  CGDirectDisplayID display_id_;
52
53  // CVDisplayLink for querying VSync timing info.
54  base::ScopedTypeRef<CVDisplayLinkRef> display_link_;
55
56  // Timer for stopping the display link if it has not been queried in
57  // the last second.
58  base::DelayTimer<DisplayLinkMac> stop_timer_;
59
60  // VSync parameters computed during Tick.
61  bool timebase_and_interval_valid_;
62  base::TimeTicks timebase_;
63  base::TimeDelta interval_;
64
65  // Lock for sharing data between UI thread and display-link thread.
66  base::Lock lock_;
67
68  // Each display link instance consumes a non-negligible number of cycles, so
69  // make all display links on the same screen share the same object.
70  typedef std::map<CGDirectDisplayID, DisplayLinkMac*> DisplayMap;
71  static base::LazyInstance<DisplayMap> display_map_;
72};
73
74}  // content
75
76#endif  // CONTENT_BROWSER_RENDERER_HOST_DISPLAY_LINK_MAC_H_
77