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Diffstat (limited to 'WebCore/platform/win/ThreadConditionWin.cpp')
-rw-r--r-- | WebCore/platform/win/ThreadConditionWin.cpp | 240 |
1 files changed, 240 insertions, 0 deletions
diff --git a/WebCore/platform/win/ThreadConditionWin.cpp b/WebCore/platform/win/ThreadConditionWin.cpp new file mode 100644 index 0000000..f2bdb78 --- /dev/null +++ b/WebCore/platform/win/ThreadConditionWin.cpp @@ -0,0 +1,240 @@ +/* + * Copyright (C) 2007 Apple 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: + * + * 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. + * 3. Neither the name of Apple Computer, Inc. ("Apple") 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 APPLE AND ITS 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 APPLE OR ITS 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. + * + * ============================================================================= + * Note: The implementation of condition variables under the Windows + * plaform was based on that of the excellent BOOST C++ library. It + * has been rewritten to fit in with the WebKit architecture and to + * use its coding conventions. + * ============================================================================= + * + * The Boost license is virtually identical to the Apple variation at the + * top of this file, but is included here for completeness: + * + * Boost Software License - Version 1.0 - August 17th, 2003 + * + * Permission is hereby granted, free of charge, to any person or organization + * obtaining a copy of the software and accompanying documentation covered by + * this license (the "Software") to use, reproduce, display, distribute, + * execute, and transmit the Software, and to prepare derivative works of the + * Software, and to permit third-parties to whom the Software is furnished to + * do so, all subject to the following: + * + * The copyright notices in the Software and this entire statement, including + * the above license grant, this restriction and the following disclaimer, + * must be included in all copies of the Software, in whole or in part, and + * all derivative works of the Software, unless such copies or derivative + * works are solely in the form of machine-executable object code generated by + * a source language processor. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT + * SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE + * FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER + * DEALINGS IN THE SOFTWARE. + */ + +#include "config.h" +#include "Logging.h" +#include "Threading.h" +#include <limits> +#include <errno.h> + +namespace WebCore { + +static const long MaxSemaphoreCount = static_cast<long>(~0UL >> 1); + +ThreadCondition::ThreadCondition() +{ + m_condition.m_timedOut = 0; + m_condition.m_blocked = 0; + m_condition.m_waitingForRemoval = 0; + m_condition.m_gate = ::CreateSemaphore(0, 1, 1, 0); + m_condition.m_queue = ::CreateSemaphore(0, 0, MaxSemaphoreCount, 0); + m_condition.m_mutex = ::CreateMutex(0, 0, 0); + + if (!m_condition.m_gate || !m_condition.m_queue || !m_condition.m_mutex) { + if (m_condition.m_gate) + ::CloseHandle(m_condition.m_gate); + if (m_condition.m_queue) + ::CloseHandle(m_condition.m_queue); + if (m_condition.m_mutex) + ::CloseHandle(m_condition.m_mutex); + } +} + +ThreadCondition::~ThreadCondition() +{ + ::CloseHandle(m_condition.m_gate); + ::CloseHandle(m_condition.m_queue); + ::CloseHandle(m_condition.m_mutex); +} + +void ThreadCondition::wait(Mutex& mutex) +{ + PlatformMutex& cs = mutex.impl(); + + // Enter the wait state. + DWORD res = ::WaitForSingleObject(m_condition.m_gate, INFINITE); + ASSERT(res == WAIT_OBJECT_0); + ++m_condition.m_blocked; + res = ::ReleaseSemaphore(m_condition.m_gate, 1, 0); + ASSERT(res); + + ::LeaveCriticalSection(&cs.m_internalMutex); + + res = ::WaitForSingleObject(m_condition.m_queue, INFINITE); + ASSERT(res == WAIT_OBJECT_0); + + res = ::WaitForSingleObject(m_condition.m_mutex, INFINITE); + ASSERT(res == WAIT_OBJECT_0); + size_t wasWaiting = m_condition.m_waitingForRemoval; + size_t wasTimedOut = m_condition.m_timedOut; + if (wasWaiting != 0) { + if (--m_condition.m_waitingForRemoval == 0) { + if (m_condition.m_blocked != 0) { + res = ::ReleaseSemaphore(m_condition.m_gate, 1, 0); // open m_gate + ASSERT(res); + wasWaiting = 0; + } + else if (m_condition.m_timedOut != 0) + m_condition.m_timedOut = 0; + } + } else if (++m_condition.m_timedOut == ((std::numeric_limits<unsigned>::max)() / 2)) { + // timeout occured, normalize the m_condition.m_timedOut count + // this may occur if many calls to wait with a timeout are made and + // no call to notify_* is made + res = ::WaitForSingleObject(m_condition.m_gate, INFINITE); + ASSERT(res == WAIT_OBJECT_0); + m_condition.m_blocked -= m_condition.m_timedOut; + res = ::ReleaseSemaphore(m_condition.m_gate, 1, 0); + ASSERT(res); + m_condition.m_timedOut = 0; + } + res = ::ReleaseMutex(m_condition.m_mutex); + ASSERT(res); + + if (wasWaiting == 1) { + for (/**/ ; wasTimedOut; --wasTimedOut) { + // better now than spurious later + res = ::WaitForSingleObject(m_condition.m_queue, INFINITE); + ASSERT(res == WAIT_OBJECT_0); + } + res = ::ReleaseSemaphore(m_condition.m_gate, 1, 0); + ASSERT(res); + } + + ::EnterCriticalSection (&cs.m_internalMutex); +} + +void ThreadCondition::signal() +{ + unsigned signals = 0; + + DWORD res = ::WaitForSingleObject(m_condition.m_mutex, INFINITE); + ASSERT(res == WAIT_OBJECT_0); + + if (m_condition.m_waitingForRemoval != 0) { // the m_gate is already closed + if (m_condition.m_blocked == 0) { + res = ::ReleaseMutex(m_condition.m_mutex); + ASSERT(res); + return; + } + + ++m_condition.m_waitingForRemoval; + --m_condition.m_blocked; + + signals = 1; + } else { + res = ::WaitForSingleObject(m_condition.m_gate, INFINITE); + ASSERT(res == WAIT_OBJECT_0); + if (m_condition.m_blocked > m_condition.m_timedOut) { + if (m_condition.m_timedOut != 0) { + m_condition.m_blocked -= m_condition.m_timedOut; + m_condition.m_timedOut = 0; + } + signals = m_condition.m_waitingForRemoval = 1; + --m_condition.m_blocked; + } else { + res = ::ReleaseSemaphore(m_condition.m_gate, 1, 0); + ASSERT(res); + } + } + + res =::ReleaseMutex(m_condition.m_mutex); + ASSERT(res); + + if (signals) { + res = ::ReleaseSemaphore(m_condition.m_queue, signals, 0); + ASSERT(res); + } +} + +void ThreadCondition::broadcast() +{ + unsigned signals = 0; + + WORD res = ::WaitForSingleObject(m_condition.m_mutex, INFINITE); + ASSERT(res == WAIT_OBJECT_0); + + if (m_condition.m_waitingForRemoval != 0) { // the m_gate is already closed + if (m_condition.m_blocked == 0) { + res = ::ReleaseMutex(m_condition.m_mutex); + ASSERT(res); + return; + } + + m_condition.m_waitingForRemoval += (signals = m_condition.m_blocked); + m_condition.m_blocked = 0; + } else { + res = ::WaitForSingleObject(m_condition.m_gate, INFINITE); + ASSERT(res == WAIT_OBJECT_0); + if (m_condition.m_blocked > m_condition.m_timedOut) { + if (m_condition.m_timedOut != 0) { + m_condition.m_blocked -= m_condition.m_timedOut; + m_condition.m_timedOut = 0; + } + signals = m_condition.m_waitingForRemoval = m_condition.m_blocked; + m_condition.m_blocked = 0; + } else { + res = ::ReleaseSemaphore(m_condition.m_gate, 1, 0); + ASSERT(res); + } + } + + res = ::ReleaseMutex(m_condition.m_mutex); + ASSERT(res); + + if (signals) { + res = ::ReleaseSemaphore(m_condition.m_queue, signals, 0); + ASSERT(res); + } +} + +} // namespace WebCore |