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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/message_pump_default.h"
#include "base/logging.h"
#include "base/time.h"
namespace base {
MessagePumpDefault::MessagePumpDefault()
: keep_running_(true),
event_(false, false) {
}
void MessagePumpDefault::Run(Delegate* delegate) {
DCHECK(keep_running_) << "Quit must have been called outside of Run!";
for (;;) {
bool did_work = delegate->DoWork();
if (!keep_running_)
break;
if (did_work)
continue;
// TODO(darin): Delayed work will be starved if DoWork continues to return
// true. We should devise a better strategy.
TimeDelta delay;
did_work = delegate->DoDelayedWork(&delay);
if (!keep_running_)
break;
if (did_work)
continue;
did_work = delegate->DoIdleWork();
if (!keep_running_)
break;
if (did_work)
continue;
// When DoIdleWork does not work, we also assume that it ran very quickly
// such that |delay| still properly indicates how long we are to sleep.
if (delay < TimeDelta::FromMilliseconds(0)) {
event_.Wait();
} else {
event_.TimedWait(delay);
}
// Since event_ is auto-reset, we don't need to do anything special here
// other than service each delegate method.
}
keep_running_ = true;
}
void MessagePumpDefault::Quit() {
keep_running_ = false;
}
void MessagePumpDefault::ScheduleWork() {
// Since this can be called on any thread, we need to ensure that our Run
// loop wakes up.
event_.Signal();
}
void MessagePumpDefault::ScheduleDelayedWork(const TimeDelta& delay) {
// We know that we can't be blocked on Wait right now since this method can
// only be called on the same thread as Run, but to ensure that when we do
// sleep, we sleep for the right time, we signal the event to cause the Run
// loop to do one more iteration.
event_.Signal();
}
} // namespace base
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