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 CAST_MEDIA_TEST_SKEWED_TICK_CLOCK_H
6#define CAST_MEDIA_TEST_SKEWED_TICK_CLOCK_H
7
8#include "base/time/tick_clock.h"
9#include "base/time/time.h"
10
11namespace media {
12namespace cast {
13namespace test {
14
15// Wraps a base::TickClock, and lets you change the speed and offset
16// of time compared to the wrapped clock. See SetSkew for how usage.
17class SkewedTickClock : public base::TickClock {
18 public:
19  // Does not take ownership of |clock_|.
20  explicit SkewedTickClock(base::TickClock* clock_);
21  // |skew| > 1.0 means clock runs faster.
22  // |offset| > 0 means clock returns times from the future.
23  // Note, |offset| is cumulative.
24  // Also note that changing the skew will never make the clock
25  // jump forwards or backwards, only changing the offset will
26  // do that.
27  void SetSkew(double skew, base::TimeDelta offset);
28  virtual base::TimeTicks NowTicks() OVERRIDE;
29
30 private:
31  base::TimeTicks SkewTicks(base::TimeTicks now);
32  base::TickClock* clock_;  // Not owned.
33  double skew_;
34  base::TimeTicks last_skew_set_time_;
35  base::TimeTicks skew_clock_at_last_set_;
36
37  DISALLOW_COPY_AND_ASSIGN(SkewedTickClock);
38};
39
40}  // namespace test
41}  // namespace cast
42}  // namespace media
43
44#endif  // CAST_MEDIA_TEST_SKEWED_TICK_CLOCK_H
45