| /* |
| * 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 |
