75 lines
2.9 KiB
C++
75 lines
2.9 KiB
C++
// Copyright 2018 The Chromium Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style license that can be
|
|
// found in the LICENSE file.
|
|
|
|
#ifndef BASE_TIME_TIME_OVERRIDE_H_
|
|
#define BASE_TIME_TIME_OVERRIDE_H_
|
|
|
|
#include "base/base_export.h"
|
|
#include "base/time/time.h"
|
|
|
|
namespace base {
|
|
|
|
using TimeNowFunction = decltype(&Time::Now);
|
|
using TimeTicksNowFunction = decltype(&TimeTicks::Now);
|
|
using ThreadTicksNowFunction = decltype(&ThreadTicks::Now);
|
|
|
|
// Time overrides should be used with extreme caution. Discuss with //base/time
|
|
// OWNERS before adding a new one.
|
|
namespace subtle {
|
|
|
|
// Override the return value of Time::Now and Time::NowFromSystemTime /
|
|
// TimeTicks::Now / ThreadTicks::Now to emulate time, e.g. for tests or to
|
|
// modify progression of time. Note that the override should be set while
|
|
// single-threaded and before the first call to Now() to avoid threading issues
|
|
// and inconsistencies in returned values. Nested overrides are not allowed.
|
|
class BASE_EXPORT ScopedTimeClockOverrides {
|
|
public:
|
|
// Pass |nullptr| for any override if it shouldn't be overriden.
|
|
ScopedTimeClockOverrides(TimeNowFunction time_override,
|
|
TimeTicksNowFunction time_ticks_override,
|
|
ThreadTicksNowFunction thread_ticks_override);
|
|
|
|
// Restores the platform default Now() functions.
|
|
~ScopedTimeClockOverrides();
|
|
|
|
static bool overrides_active() { return overrides_active_; }
|
|
|
|
private:
|
|
static bool overrides_active_;
|
|
|
|
DISALLOW_COPY_AND_ASSIGN(ScopedTimeClockOverrides);
|
|
};
|
|
|
|
// These methods return the platform default Time::Now / TimeTicks::Now /
|
|
// ThreadTicks::Now values even while an override is in place. These methods
|
|
// should only be used in places where emulated time should be disregarded. For
|
|
// example, they can be used to implement test timeouts for tests that may
|
|
// override time.
|
|
BASE_EXPORT Time TimeNowIgnoringOverride();
|
|
BASE_EXPORT Time TimeNowFromSystemTimeIgnoringOverride();
|
|
BASE_EXPORT TimeTicks TimeTicksNowIgnoringOverride();
|
|
BASE_EXPORT ThreadTicks ThreadTicksNowIgnoringOverride();
|
|
|
|
} // namespace subtle
|
|
|
|
namespace internal {
|
|
|
|
// These function pointers are used by platform-independent implementations of
|
|
// the Now() methods and ScopedTimeClockOverrides. They are set to point to the
|
|
// respective NowIgnoringOverride functions by default, but can also be set by
|
|
// platform-specific code to select a default implementation at runtime, thereby
|
|
// avoiding the indirection via the NowIgnoringOverride functions. Note that the
|
|
// pointers can be overridden and later reset to the NowIgnoringOverride
|
|
// functions by ScopedTimeClockOverrides.
|
|
extern TimeNowFunction g_time_now_function;
|
|
extern TimeNowFunction g_time_now_from_system_time_function;
|
|
extern TimeTicksNowFunction g_time_ticks_now_function;
|
|
extern ThreadTicksNowFunction g_thread_ticks_now_function;
|
|
|
|
} // namespace internal
|
|
|
|
} // namespace base
|
|
|
|
#endif // BASE_TIME_TIME_OVERRIDE_H_
|