The Tor Browser: security/sandbox/chromium/base/profiler/tracked

     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.

     5 #ifndef BASE_PROFILER_TRACKED_TIME_H_

     6 #define BASE_PROFILER_TRACKED_TIME_H_

     9 #include "base/base_export.h"

    10 #include "base/basictypes.h"

    11 #include "base/time/time.h"

    13 namespace tracked_objects {

    15 //------------------------------------------------------------------------------

    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).

    26 class BASE_EXPORT Duration {  // Similar to base::TimeDelta.

    27  public:

    28   Duration();

    30   Duration& operator+=(const Duration& other);

    31   Duration operator+(const Duration& other) const;

    33   bool operator==(const Duration& other) const;

    34   bool operator!=(const Duration& other) const;

    35   bool operator>(const Duration& other) const;

    37   static Duration FromMilliseconds(int ms);

    39   int32 InMilliseconds() const;

    41  private:

    42   friend class TrackedTime;

    43   explicit Duration(int32 duration);

    45   // Internal time is stored directly in milliseconds.

    46   int32 ms_;

    47 };

    49 class BASE_EXPORT TrackedTime {  // Similar to base::TimeTicks.

    50  public:

    51   TrackedTime();

    52   explicit TrackedTime(const base::TimeTicks& time);

    54   static TrackedTime Now();

    55   Duration operator-(const TrackedTime& other) const;

    56   TrackedTime operator+(const Duration& other) const;

    57   bool is_null() const;

    59   static TrackedTime FromMilliseconds(int32 ms) { return TrackedTime(ms); }

    61  private:

    62   friend class Duration;

    63   explicit TrackedTime(int32 ms);

    65   // Internal duration is stored directly in milliseconds.

    66   uint32 ms_;

    67 };

    69 }  // namespace tracked_objects

    71 #endif  // BASE_PROFILER_TRACKED_TIME_H_

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