191 lines
4.8 KiB
C++
191 lines
4.8 KiB
C++
/*
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* Copyright (C) 2010 Apple Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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* THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "config.h"
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#include <wtf/RunLoop.h>
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#include <wtf/NeverDestroyed.h>
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#include <wtf/StdLibExtras.h>
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namespace WTF {
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static RunLoop* s_mainRunLoop;
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#if USE(WEB_THREAD)
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static RunLoop* s_webRunLoop;
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#endif
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// Helper class for ThreadSpecificData.
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class RunLoop::Holder {
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WTF_MAKE_FAST_ALLOCATED;
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public:
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Holder()
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: m_runLoop(adoptRef(*new RunLoop))
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{
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}
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~Holder()
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{
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m_runLoop->threadWillExit();
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}
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RunLoop& runLoop() { return m_runLoop; }
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private:
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Ref<RunLoop> m_runLoop;
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};
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void RunLoop::initializeMain()
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{
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RELEASE_ASSERT(!s_mainRunLoop);
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s_mainRunLoop = &RunLoop::current();
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}
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auto RunLoop::runLoopHolder() -> ThreadSpecific<Holder>&
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{
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static LazyNeverDestroyed<ThreadSpecific<Holder>> runLoopHolder;
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static std::once_flag onceKey;
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std::call_once(onceKey, [&] {
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runLoopHolder.construct();
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});
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return runLoopHolder;
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}
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RunLoop& RunLoop::current()
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{
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return runLoopHolder()->runLoop();
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}
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RunLoop& RunLoop::main()
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{
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ASSERT(s_mainRunLoop);
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return *s_mainRunLoop;
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}
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#if USE(WEB_THREAD)
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void RunLoop::initializeWeb()
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{
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RELEASE_ASSERT(!s_webRunLoop);
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s_webRunLoop = &RunLoop::current();
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}
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RunLoop& RunLoop::web()
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{
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ASSERT(s_webRunLoop);
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return *s_webRunLoop;
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}
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RunLoop* RunLoop::webIfExists()
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{
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return s_webRunLoop;
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}
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#endif
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bool RunLoop::isMain()
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{
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ASSERT(s_mainRunLoop);
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// Avoid constructing the RunLoop for the current thread if it has not been created yet.
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return runLoopHolder().isSet() && s_mainRunLoop == &RunLoop::current();
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}
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void RunLoop::performWork()
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{
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bool didSuspendFunctions = false;
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{
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Locker locker { m_nextIterationLock };
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// If the RunLoop re-enters or re-schedules, we're expected to execute all functions in order.
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while (!m_currentIteration.isEmpty())
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m_nextIteration.prepend(m_currentIteration.takeLast());
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m_currentIteration = std::exchange(m_nextIteration, { });
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}
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while (!m_currentIteration.isEmpty()) {
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if (m_isFunctionDispatchSuspended) {
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didSuspendFunctions = true;
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break;
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}
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auto function = m_currentIteration.takeFirst();
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function();
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}
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// Suspend only for a single cycle.
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m_isFunctionDispatchSuspended = false;
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m_hasSuspendedFunctions = didSuspendFunctions;
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if (m_hasSuspendedFunctions)
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wakeUp();
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}
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void RunLoop::dispatch(Function<void()>&& function)
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{
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RELEASE_ASSERT(function);
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bool needsWakeup = false;
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{
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Locker locker { m_nextIterationLock };
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needsWakeup = m_nextIteration.isEmpty();
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m_nextIteration.append(WTFMove(function));
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}
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if (needsWakeup)
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wakeUp();
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}
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void RunLoop::dispatchAfter(Seconds delay, Function<void()>&& function)
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{
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RELEASE_ASSERT(function);
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auto timer = new DispatchTimer(*this);
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timer->setFunction([timer, function = WTFMove(function)] {
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function();
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delete timer;
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});
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timer->startOneShot(delay);
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}
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void RunLoop::suspendFunctionDispatchForCurrentCycle()
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{
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// Don't suspend if there are already suspended functions to avoid unexecuted function pile-up.
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if (m_isFunctionDispatchSuspended || m_hasSuspendedFunctions)
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return;
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m_isFunctionDispatchSuspended = true;
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// Wake up (even if there is nothing to do) to disable suspension.
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wakeUp();
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}
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void RunLoop::threadWillExit()
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{
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m_currentIteration.clear();
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{
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Locker locker { m_nextIterationLock };
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m_nextIteration.clear();
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}
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}
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} // namespace WTF
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