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 #include <stdint.h> 9 10 #include "base/base_export.h" 11 #include "base/time/time.h" 12 13 namespace 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 26 class 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_t InMilliseconds() const; 40 41 private: 42 friend class TrackedTime; 43 explicit Duration(int32_t duration); 44 45 // Internal time is stored directly in milliseconds. 46 int32_t ms_; 47 }; 48 49 class 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 FromMilliseconds(int32_t ms)59 static TrackedTime FromMilliseconds(int32_t ms) { return TrackedTime(ms); } 60 61 private: 62 friend class Duration; 63 explicit TrackedTime(int32_t ms); 64 65 // Internal duration is stored directly in milliseconds. 66 uint32_t ms_; 67 }; 68 69 } // namespace tracked_objects 70 71 #endif // BASE_PROFILER_TRACKED_TIME_H_ 72