media/cast/test/skewed_tick_clock.h

   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
  11 namespace media {
  12 namespace cast {
  13 namespace 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.
  17 class 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   base::TimeTicks NowTicks() final;
  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