// Copyright (c) 2012 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_TICK_CLOCK_H_ #define BASE_TIME_TICK_CLOCK_H_ #include "base/base_export.h" #include "base/time/time.h" namespace base { // A TickClock is an interface for objects that vend TimeTicks. It is // intended to be able to test the behavior of classes with respect to // non-decreasing time. // // Note: Overriding Time/TimeTicks altogether via // TaskEnvironment::TimeSource::MOCK_TIME is now the preferred way of overriding // time in unit tests. As such, there shouldn't be many new use cases for // TickClock/DefaultTickClock anymore. // // See DefaultTickClock (base/time/default_tick_clock.h) for the default // implementation that simply uses TimeTicks::Now(). // // (Other implementations that use TimeTicks::NowFromSystemTime() should // be added as needed.) // // See SimpleTestTickClock (base/test/simple_test_tick_clock.h) for a // simple test implementation. // // See Clock (base/time/clock.h) for the equivalent interface for Times. class BASE_EXPORT TickClock { public: virtual ~TickClock(); // NowTicks() must be safe to call from any thread. The caller may // assume that NowTicks() is monotonic (but not strictly monotonic). // In other words, the returned TimeTicks will never decrease with // time, although they might "stand still". virtual TimeTicks NowTicks() const = 0; }; } // namespace base #endif // BASE_TIME_TICK_CLOCK_H_