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// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_TIMER_ELAPSED_TIMER_H_
#define BASE_TIMER_ELAPSED_TIMER_H_
#include "base/base_export.h"
#include "base/time/time.h"
namespace base {
// A simple wrapper around TimeTicks::Now().
class BASE_EXPORT ElapsedTimer {
public:
ElapsedTimer();
ElapsedTimer(const ElapsedTimer&) = default;
ElapsedTimer& operator=(const ElapsedTimer&) = default;
// Returns the time elapsed since object construction.
TimeDelta Elapsed() const;
// Returns the timestamp of the creation of this timer.
TimeTicks start_time() const { return start_time_; }
private:
TimeTicks start_time_;
};
// A simple wrapper around ThreadTicks::Now().
class BASE_EXPORT ElapsedThreadTimer {
public:
ElapsedThreadTimer();
ElapsedThreadTimer(const ElapsedThreadTimer&) = default;
ElapsedThreadTimer& operator=(const ElapsedThreadTimer&) = default;
// Returns the ThreadTicks time elapsed since object construction.
// Only valid if |is_supported()| returns true, otherwise returns TimeDelta().
TimeDelta Elapsed() const;
bool is_supported() const { return is_supported_; }
private:
bool is_supported_;
ThreadTicks begin_;
};
// A simple wrapper around LiveTicks::Now().
class BASE_EXPORT ElapsedLiveTimer {
public:
ElapsedLiveTimer();
ElapsedLiveTimer(const ElapsedLiveTimer&) = default;
ElapsedLiveTimer& operator=(const ElapsedLiveTimer&) = default;
// Returns the time elapsed since object construction, not including time that
// the system was suspended.
TimeDelta Elapsed() const;
// Returns the timestamp of the creation of this timer.
LiveTicks start_time() const { return start_time_; }
private:
LiveTicks start_time_;
};
// Whenever there's a ScopedMockElapsedTimersForTest in scope, every
// ElapsedTimer (and variants like ElapsedThreadTimer and ElapsedLiveTimer) will
// always return kMockElapsedTime from Elapsed(). This is useful, for example,
// in unit tests that verify that their impl records timing histograms. It
// enables such tests to observe reliable timings.
class BASE_EXPORT ScopedMockElapsedTimersForTest {
public:
static constexpr TimeDelta kMockElapsedTime = Milliseconds(1337);
// ScopedMockElapsedTimersForTest is not thread-safe (it must be instantiated
// in a test before other threads begin using ElapsedTimers; and it must
// conversely outlive any usage of ElapsedTimer in that test).
ScopedMockElapsedTimersForTest();
ScopedMockElapsedTimersForTest(const ScopedMockElapsedTimersForTest&) =
delete;
ScopedMockElapsedTimersForTest& operator=(
const ScopedMockElapsedTimersForTest&) = delete;
~ScopedMockElapsedTimersForTest();
};
} // namespace base
#endif // BASE_TIMER_ELAPSED_TIMER_H_
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