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Diffstat (limited to 'base/waitable_event_generic.cc')
-rw-r--r-- | base/waitable_event_generic.cc | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/base/waitable_event_generic.cc b/base/waitable_event_generic.cc new file mode 100644 index 0000000..f036f8d --- /dev/null +++ b/base/waitable_event_generic.cc @@ -0,0 +1,96 @@ +// Copyright 2008, Google Inc. +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following disclaimer +// in the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +#include "base/waitable_event.h" + +namespace base { + +WaitableEvent::WaitableEvent(bool manual_reset, bool signaled) + : lock_(), + cvar_(&lock_), + signaled_(signaled), + manual_reset_(manual_reset) { +} + +WaitableEvent::~WaitableEvent() { + // Members are destroyed in the reverse of their initialization order, so we + // should not have to worry about lock_ being destroyed before cvar_. +} + +void WaitableEvent::Reset() { + AutoLock locked(lock_); + signaled_ = false; +} + +void WaitableEvent::Signal() { + AutoLock locked(lock_); + if (!signaled_) { + signaled_ = true; + if (manual_reset_) { + cvar_.Broadcast(); + } else { + cvar_.Signal(); + } + } +} + +bool WaitableEvent::IsSignaled() { + return TimedWait(TimeDelta::FromMilliseconds(0)); +} + +bool WaitableEvent::Wait() { + AutoLock locked(lock_); + while (!signaled_) + cvar_.Wait(); + if (!manual_reset_) + signaled_ = false; + return true; +} + +bool WaitableEvent::TimedWait(const TimeDelta& max_time) { + AutoLock locked(lock_); + // In case of spurious wake-ups, we need to adjust the amount of time that we + // spend sleeping. + TimeDelta total_time; + for (;;) { + TimeTicks start = TimeTicks::Now(); + cvar_.TimedWait(max_time - total_time); + if (signaled_) + break; + total_time += TimeTicks::Now() - start; + if (total_time >= max_time) + break; + } + bool result = signaled_; + if (!manual_reset_) + signaled_ = false; + return result; +} + +} // namespace base |