1/* 2 * Copyright (C) 2010 Apple Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' 14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS 17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF 23 * THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26#include "config.h" 27#include "WorkQueue.h" 28 29#include <wtf/Threading.h> 30 31inline WorkQueue::WorkItemWin::WorkItemWin(const Function<void()>& function, WorkQueue* queue) 32 : m_function(function) 33 , m_queue(queue) 34{ 35} 36 37PassRefPtr<WorkQueue::WorkItemWin> WorkQueue::WorkItemWin::create(const Function<void()>& function, WorkQueue* queue) 38{ 39 return adoptRef(new WorkItemWin(function, queue)); 40} 41 42WorkQueue::WorkItemWin::~WorkItemWin() 43{ 44} 45 46inline WorkQueue::HandleWorkItem::HandleWorkItem(HANDLE handle, const Function<void()>& function, WorkQueue* queue) 47 : WorkItemWin(function, queue) 48 , m_handle(handle) 49 , m_waitHandle(0) 50{ 51 ASSERT_ARG(handle, handle); 52} 53 54PassRefPtr<WorkQueue::HandleWorkItem> WorkQueue::HandleWorkItem::createByAdoptingHandle(HANDLE handle, const Function<void()>& function, WorkQueue* queue) 55{ 56 return adoptRef(new HandleWorkItem(handle, function, queue)); 57} 58 59WorkQueue::HandleWorkItem::~HandleWorkItem() 60{ 61 ::CloseHandle(m_handle); 62} 63 64void WorkQueue::handleCallback(void* context, BOOLEAN timerOrWaitFired) 65{ 66 ASSERT_ARG(context, context); 67 ASSERT_ARG(timerOrWaitFired, !timerOrWaitFired); 68 69 WorkItemWin* item = static_cast<WorkItemWin*>(context); 70 RefPtr<WorkQueue> queue = item->queue(); 71 72 { 73 MutexLocker lock(queue->m_workItemQueueLock); 74 queue->m_workItemQueue.append(item); 75 76 // If no other thread is performing work, we can do it on this thread. 77 if (!queue->tryRegisterAsWorkThread()) { 78 // Some other thread is performing work. Since we hold the queue lock, we can be sure 79 // that the work thread is not exiting due to an empty queue and will process the work 80 // item we just added to it. If we weren't holding the lock we'd have to signal 81 // m_performWorkEvent to make sure the work item got picked up. 82 return; 83 } 84 } 85 86 queue->performWorkOnRegisteredWorkThread(); 87} 88 89void WorkQueue::registerHandle(HANDLE handle, const Function<void()>& function) 90{ 91 RefPtr<HandleWorkItem> handleItem = HandleWorkItem::createByAdoptingHandle(handle, function, this); 92 93 { 94 MutexLocker lock(m_handlesLock); 95 ASSERT_ARG(handle, !m_handles.contains(handle)); 96 m_handles.set(handle, handleItem); 97 } 98 99 HANDLE waitHandle; 100 if (!::RegisterWaitForSingleObject(&waitHandle, handle, handleCallback, handleItem.get(), INFINITE, WT_EXECUTEDEFAULT)) { 101 DWORD error = ::GetLastError(); 102 ASSERT_NOT_REACHED(); 103 } 104 handleItem->setWaitHandle(waitHandle); 105} 106 107void WorkQueue::unregisterAndCloseHandle(HANDLE handle) 108{ 109 RefPtr<HandleWorkItem> item; 110 { 111 MutexLocker locker(m_handlesLock); 112 ASSERT_ARG(handle, m_handles.contains(handle)); 113 item = m_handles.take(handle); 114 } 115 116 unregisterWaitAndDestroyItemSoon(item.release()); 117} 118 119DWORD WorkQueue::workThreadCallback(void* context) 120{ 121 ASSERT_ARG(context, context); 122 123 WorkQueue* queue = static_cast<WorkQueue*>(context); 124 125 if (!queue->tryRegisterAsWorkThread()) 126 return 0; 127 128 queue->performWorkOnRegisteredWorkThread(); 129 return 0; 130} 131 132void WorkQueue::performWorkOnRegisteredWorkThread() 133{ 134 ASSERT(m_isWorkThreadRegistered); 135 136 m_workItemQueueLock.lock(); 137 138 while (!m_workItemQueue.isEmpty()) { 139 Vector<RefPtr<WorkItemWin> > workItemQueue; 140 m_workItemQueue.swap(workItemQueue); 141 142 // Allow more work to be scheduled while we're not using the queue directly. 143 m_workItemQueueLock.unlock(); 144 for (size_t i = 0; i < workItemQueue.size(); ++i) 145 workItemQueue[i]->function()(); 146 m_workItemQueueLock.lock(); 147 } 148 149 // One invariant we maintain is that any work scheduled while a work thread is registered will 150 // be handled by that work thread. Unregister as the work thread while the queue lock is still 151 // held so that no work can be scheduled while we're still registered. 152 unregisterAsWorkThread(); 153 154 m_workItemQueueLock.unlock(); 155} 156 157void WorkQueue::platformInitialize(const char* name) 158{ 159 m_isWorkThreadRegistered = 0; 160 m_timerQueue = ::CreateTimerQueue(); 161 ASSERT_WITH_MESSAGE(m_timerQueue, "::CreateTimerQueue failed with error %lu", ::GetLastError()); 162} 163 164bool WorkQueue::tryRegisterAsWorkThread() 165{ 166 LONG result = ::InterlockedCompareExchange(&m_isWorkThreadRegistered, 1, 0); 167 ASSERT(!result || result == 1); 168 return !result; 169} 170 171void WorkQueue::unregisterAsWorkThread() 172{ 173 LONG result = ::InterlockedCompareExchange(&m_isWorkThreadRegistered, 0, 1); 174 ASSERT_UNUSED(result, result == 1); 175} 176 177void WorkQueue::platformInvalidate() 178{ 179#if !ASSERT_DISABLED 180 MutexLocker lock(m_handlesLock); 181 ASSERT(m_handles.isEmpty()); 182#endif 183 184 // FIXME: We need to ensure that any timer-queue timers that fire after this point don't try to 185 // access this WorkQueue <http://webkit.org/b/44690>. 186 ::DeleteTimerQueueEx(m_timerQueue, 0); 187} 188 189void WorkQueue::dispatch(const Function<void()>& function) 190{ 191 MutexLocker locker(m_workItemQueueLock); 192 193 m_workItemQueue.append(WorkItemWin::create(function, this)); 194 195 // Spawn a work thread to perform the work we just added. As an optimization, we avoid 196 // spawning the thread if a work thread is already registered. This prevents multiple work 197 // threads from being spawned in most cases. (Note that when a work thread has been spawned but 198 // hasn't registered itself yet, m_isWorkThreadRegistered will be false and we'll end up 199 // spawning a second work thread here. But work thread registration process will ensure that 200 // only one thread actually ends up performing work.) 201 if (!m_isWorkThreadRegistered) 202 ::QueueUserWorkItem(workThreadCallback, this, WT_EXECUTEDEFAULT); 203} 204 205struct TimerContext : public ThreadSafeRefCounted<TimerContext> { 206 static PassRefPtr<TimerContext> create() { return adoptRef(new TimerContext); } 207 208 WorkQueue* queue; 209 Function<void()> function; 210 Mutex timerMutex; 211 HANDLE timer; 212 213private: 214 TimerContext() : queue(0), timer(0) { } 215}; 216 217void WorkQueue::timerCallback(void* context, BOOLEAN timerOrWaitFired) 218{ 219 ASSERT_ARG(context, context); 220 ASSERT_UNUSED(timerOrWaitFired, timerOrWaitFired); 221 222 // Balanced by leakRef in scheduleWorkAfterDelay. 223 RefPtr<TimerContext> timerContext = adoptRef(static_cast<TimerContext*>(context)); 224 225 timerContext->queue->dispatch(timerContext->function); 226 227 MutexLocker lock(timerContext->timerMutex); 228 ASSERT(timerContext->timer); 229 ASSERT(timerContext->queue->m_timerQueue); 230 if (!::DeleteTimerQueueTimer(timerContext->queue->m_timerQueue, timerContext->timer, 0)) { 231 // Getting ERROR_IO_PENDING here means that the timer will be destroyed once the callback is done executing. 232 ASSERT_WITH_MESSAGE(::GetLastError() == ERROR_IO_PENDING, "::DeleteTimerQueueTimer failed with error %lu", ::GetLastError()); 233 } 234} 235 236void WorkQueue::dispatchAfterDelay(const Function<void()>& function, double delay) 237{ 238 ASSERT(m_timerQueue); 239 240 RefPtr<TimerContext> context = TimerContext::create(); 241 context->queue = this; 242 context->function = function; 243 244 { 245 // The timer callback could fire before ::CreateTimerQueueTimer even returns, so we protect 246 // context->timer with a mutex to ensure the timer callback doesn't access it before the 247 // timer handle has been stored in it. 248 MutexLocker lock(context->timerMutex); 249 250 // Since our timer callback is quick, we can execute in the timer thread itself and avoid 251 // an extra thread switch over to a worker thread. 252 if (!::CreateTimerQueueTimer(&context->timer, m_timerQueue, timerCallback, context.get(), delay * 1000, 0, WT_EXECUTEINTIMERTHREAD)) { 253 ASSERT_WITH_MESSAGE(false, "::CreateTimerQueueTimer failed with error %lu", ::GetLastError()); 254 return; 255 } 256 } 257 258 // The timer callback will handle destroying context. 259 context.release().leakRef(); 260} 261 262void WorkQueue::unregisterWaitAndDestroyItemSoon(PassRefPtr<HandleWorkItem> item) 263{ 264 // We're going to make a blocking call to ::UnregisterWaitEx before closing the handle. (The 265 // blocking version of ::UnregisterWaitEx is much simpler than the non-blocking version.) If we 266 // do this on the current thread, we'll deadlock if we're currently in a callback function for 267 // the wait we're unregistering. So instead we do it asynchronously on some other worker thread. 268 269 ::QueueUserWorkItem(unregisterWaitAndDestroyItemCallback, item.leakRef(), WT_EXECUTEDEFAULT); 270} 271 272DWORD WINAPI WorkQueue::unregisterWaitAndDestroyItemCallback(void* context) 273{ 274 ASSERT_ARG(context, context); 275 RefPtr<HandleWorkItem> item = adoptRef(static_cast<HandleWorkItem*>(context)); 276 277 // Now that we know we're not in a callback function for the wait we're unregistering, we can 278 // make a blocking call to ::UnregisterWaitEx. 279 if (!::UnregisterWaitEx(item->waitHandle(), INVALID_HANDLE_VALUE)) { 280 DWORD error = ::GetLastError(); 281 ASSERT_NOT_REACHED(); 282 } 283 284 return 0; 285} 286