1// Copyright (c) 2012 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 BASE_PROFILER_TRACKED_TIME_H_
6#define BASE_PROFILER_TRACKED_TIME_H_
7
8
9#include "base/base_export.h"
10#include "base/basictypes.h"
11#include "base/time/time.h"
12
13namespace tracked_objects {
14
15//------------------------------------------------------------------------------
16
17// TimeTicks maintains a wasteful 64 bits of data (we need less than 32), and on
18// windows, a 64 bit timer is expensive to even obtain. We use a simple
19// millisecond counter for most of our time values, as well as millisecond units
20// of duration between those values.  This means we can only handle durations
21// up to 49 days (range), or 24 days (non-negative time durations).
22// We only define enough methods to service the needs of the tracking classes,
23// and our interfaces are modeled after what TimeTicks and TimeDelta use (so we
24// can swap them into place if we want to use the "real" classes).
25
26class BASE_EXPORT Duration {  // Similar to base::TimeDelta.
27 public:
28  Duration();
29
30  Duration& operator+=(const Duration& other);
31  Duration operator+(const Duration& other) const;
32
33  bool operator==(const Duration& other) const;
34  bool operator!=(const Duration& other) const;
35  bool operator>(const Duration& other) const;
36
37  static Duration FromMilliseconds(int ms);
38
39  int32 InMilliseconds() const;
40
41 private:
42  friend class TrackedTime;
43  explicit Duration(int32 duration);
44
45  // Internal time is stored directly in milliseconds.
46  int32 ms_;
47};
48
49class BASE_EXPORT TrackedTime {  // Similar to base::TimeTicks.
50 public:
51  TrackedTime();
52  explicit TrackedTime(const base::TimeTicks& time);
53
54  static TrackedTime Now();
55  Duration operator-(const TrackedTime& other) const;
56  TrackedTime operator+(const Duration& other) const;
57  bool is_null() const;
58
59  static TrackedTime FromMilliseconds(int32 ms) { return TrackedTime(ms); }
60
61 private:
62  friend class Duration;
63  explicit TrackedTime(int32 ms);
64
65  // Internal duration is stored directly in milliseconds.
66  uint32 ms_;
67};
68
69}  // namespace tracked_objects
70
71#endif  // BASE_PROFILER_TRACKED_TIME_H_
72