jar@chromium.org | 3d6a82f | 2011-11-05 09:39:27 +0900 | [diff] [blame] | 1 | // Copyright (c) 2011 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.h" |
| 12 | |
| 13 | namespace tracked_objects { |
| 14 | |
| 15 | //------------------------------------------------------------------------------ |
| 16 | |
| 17 | #define USE_FAST_TIME_CLASS_FOR_DURATION_CALCULATIONS |
| 18 | |
| 19 | #if defined(USE_FAST_TIME_CLASS_FOR_DURATION_CALCULATIONS) |
| 20 | |
| 21 | // TimeTicks maintains a wasteful 64 bits of data (we need less than 32), and on |
| 22 | // windows, a 64 bit timer is expensive to even obtain. We use a simple |
| 23 | // millisecond counter for most of our time values, as well as millisecond units |
| 24 | // of duration between those values. This means we can only handle durations |
| 25 | // up to 49 days (range), or 24 days (non-negative time durations). |
| 26 | // We only define enough methods to service the needs of the tracking classes, |
| 27 | // and our interfaces are modeled after what TimeTicks and TimeDelta use (so we |
| 28 | // can swap them into place if we want to use the "real" classes). |
| 29 | |
| 30 | class BASE_EXPORT Duration { // Similar to base::TimeDelta. |
| 31 | public: |
| 32 | Duration(); |
| 33 | |
| 34 | Duration& operator+=(const Duration& other); |
| 35 | Duration operator+(const Duration& other) const; |
| 36 | |
| 37 | bool operator==(const Duration& other) const; |
| 38 | bool operator!=(const Duration& other) const; |
| 39 | bool operator>(const Duration& other) const; |
| 40 | |
| 41 | static Duration FromMilliseconds(int ms); |
| 42 | |
| 43 | int32 InMilliseconds() const; |
| 44 | |
| 45 | private: |
| 46 | friend class TrackedTime; |
| 47 | explicit Duration(int32 duration); |
| 48 | |
| 49 | // Internal time is stored directly in milliseconds. |
| 50 | int32 ms_; |
| 51 | }; |
| 52 | |
| 53 | class BASE_EXPORT TrackedTime { // Similar to base::TimeTicks. |
| 54 | public: |
| 55 | TrackedTime(); |
| 56 | explicit TrackedTime(const base::TimeTicks& time); |
| 57 | |
| 58 | static TrackedTime Now(); |
| 59 | Duration operator-(const TrackedTime& other) const; |
| 60 | TrackedTime operator+(const Duration& other) const; |
| 61 | bool is_null() const; |
| 62 | |
| 63 | private: |
| 64 | friend class Duration; |
| 65 | explicit TrackedTime(int32 ms); |
| 66 | |
| 67 | // Internal duration is stored directly in milliseconds. |
| 68 | uint32 ms_; |
| 69 | }; |
| 70 | |
| 71 | #else |
| 72 | |
| 73 | // Just use full 64 bit time calculations, and the slower TimeTicks::Now(). |
| 74 | // This allows us (as an alternative) to test with larger ranges of times, and |
| 75 | // with a more thoroughly tested class. |
| 76 | |
| 77 | typedef base::TimeTicks TrackedTime; |
| 78 | typedef base::TimeDelta Duration; |
| 79 | |
| 80 | #endif // USE_FAST_TIME_CLASS_FOR_DURATION_CALCULATIONS |
| 81 | |
| 82 | } // namespace tracked_objects |
| 83 | |
| 84 | #endif // BASE_PROFILER_TRACKED_TIME_H_ |