1 // Copyright 2018 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 #include "base/task/sequence_manager/lazy_now.h" 6 7 #include "base/time/tick_clock.h" 8 9 namespace base { 10 namespace sequence_manager { 11 LazyNow(TimeTicks now)12LazyNow::LazyNow(TimeTicks now) : tick_clock_(nullptr), now_(now) {} 13 LazyNow(const TickClock * tick_clock)14LazyNow::LazyNow(const TickClock* tick_clock) 15 : tick_clock_(tick_clock), now_() { 16 DCHECK(tick_clock); 17 } 18 LazyNow(LazyNow && move_from)19LazyNow::LazyNow(LazyNow&& move_from) noexcept 20 : tick_clock_(move_from.tick_clock_), now_(move_from.now_) { 21 move_from.tick_clock_ = nullptr; 22 move_from.now_ = nullopt; 23 } 24 Now()25TimeTicks LazyNow::Now() { 26 // It looks tempting to avoid using Optional and to rely on is_null() instead, 27 // but in some test environments clock intentionally starts from zero. 28 if (!now_) { 29 DCHECK(tick_clock_); // It can fire only on use after std::move. 30 now_ = tick_clock_->NowTicks(); 31 } 32 return *now_; 33 } 34 35 } // namespace sequence_manager 36 } // namespace base 37