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// 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
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