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/*
* Copyright (C) 2017 Yusuke Suzuki <utatane.tea@gmail.com>.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 APPLE INC. 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 "config.h"
#include <wtf/WorkerPool.h>
namespace WTF {
class WorkerPool::Worker final : public AutomaticThread {
public:
friend class WorkerPool;
Worker(const AbstractLocker& locker, WorkerPool& pool, Box<Lock> lock, Ref<AutomaticThreadCondition>&& condition, Seconds timeout)
: AutomaticThread(locker, lock, WTFMove(condition), timeout)
, m_pool(pool)
{
}
PollResult poll(const AbstractLocker&) final
{
if (m_pool.m_tasks.isEmpty())
return PollResult::Wait;
m_task = m_pool.m_tasks.takeFirst();
if (!m_task)
return PollResult::Stop;
return PollResult::Work;
}
WorkResult work() final
{
m_task();
m_task = nullptr;
return WorkResult::Continue;
}
void threadDidStart() final
{
Locker locker { *m_pool.m_lock };
m_pool.m_numberOfActiveWorkers++;
}
void threadIsStopping(const AbstractLocker&) final
{
m_pool.m_numberOfActiveWorkers--;
}
bool shouldSleep(const AbstractLocker& locker) final
{
return m_pool.shouldSleep(locker);
}
ASCIILiteral name() const final
{
return m_pool.name();
}
private:
WorkerPool& m_pool;
Function<void()> m_task;
};
WorkerPool::WorkerPool(ASCIILiteral name, unsigned numberOfWorkers, Seconds timeout)
: m_lock(Box<Lock>::create())
, m_condition(AutomaticThreadCondition::create())
, m_timeout(timeout)
, m_name(name)
{
Locker locker { *m_lock };
for (unsigned i = 0; i < numberOfWorkers; ++i)
m_workers.append(adoptRef(*new Worker(locker, *this, m_lock, m_condition.copyRef(), timeout)));
}
WorkerPool::~WorkerPool()
{
{
Locker locker { *m_lock };
for (unsigned i = m_workers.size(); i--;)
m_tasks.append(nullptr); // Use null task to indicate that we want the thread to terminate.
m_condition->notifyAll(locker);
}
for (auto& worker : m_workers)
worker->join();
ASSERT(!m_numberOfActiveWorkers);
}
bool WorkerPool::shouldSleep(const AbstractLocker&)
{
if (m_timeout > 0_s && m_timeout.isInfinity())
return false;
MonotonicTime currentTime = MonotonicTime::now();
if (m_lastTimeoutTime.isNaN() || (currentTime >= (m_lastTimeoutTime + m_timeout))) {
m_lastTimeoutTime = currentTime;
return true;
}
return false;
}
void WorkerPool::postTask(Function<void()>&& task)
{
Locker locker { *m_lock };
m_tasks.append(WTFMove(task));
m_condition->notifyOne(locker);
}
}
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