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| 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_ |
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