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_CLOCK_H_ 6 #define BASE_CLOCK_H_ 7 8 #include "base/base_export.h" 9 #include "base/time/time.h" 10 11 namespace base { 12 13 // A Clock is an interface for objects that vend Times. It is 14 // intended to be able to test the behavior of classes with respect to 15 // time. 16 // 17 // See DefaultClock (base/time/default_clock.h) for the default 18 // implementation that simply uses Time::Now(). 19 // 20 // (An implementation that uses Time::SystemTime() should be added as 21 // needed.) 22 // 23 // See SimpleTestClock (base/test/simple_test_clock.h) for a simple 24 // test implementation. 25 // 26 // See TickClock (base/time/tick_clock.h) for the equivalent interface for 27 // TimeTicks. 28 class BASE_EXPORT Clock { 29 public: 30 virtual ~Clock(); 31 32 // Now() must be safe to call from any thread. The caller cannot 33 // make any ordering assumptions about the returned Time. For 34 // example, the system clock may change to an earlier time. 35 virtual Time Now() = 0; 36 }; 37 38 } // namespace base 39 40 #endif // BASE_CLOCK_H_ 41
