1 /* 2 * Copyright (C) 2007, 2008 Apple Inc. All rights reserved. 3 * Copyright (C) 2009 Google Inc. All rights reserved. 4 * Copyright (C) 2009 Torch Mobile, Inc. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of 16 * its contributors may be used to endorse or promote products derived 17 * from this software without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY 20 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 21 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 22 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY 23 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 24 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 25 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 26 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 /* 32 * There are numerous academic and practical works on how to implement pthread_cond_wait/pthread_cond_signal/pthread_cond_broadcast 33 * functions on Win32. Here is one example: http://www.cs.wustl.edu/~schmidt/win32-cv-1.html which is widely credited as a 'starting point' 34 * of modern attempts. There are several more or less proven implementations, one in Boost C++ library (http://www.boost.org) and another 35 * in pthreads-win32 (http://sourceware.org/pthreads-win32/). 36 * 37 * The number of articles and discussions is the evidence of significant difficulties in implementing these primitives correctly. 38 * The brief search of revisions, ChangeLog entries, discussions in comp.programming.threads and other places clearly documents 39 * numerous pitfalls and performance problems the authors had to overcome to arrive to the suitable implementations. 40 * Optimally, WebKit would use one of those supported/tested libraries directly. To roll out our own implementation is impractical, 41 * if even for the lack of sufficient testing. However, a faithful reproduction of the code from one of the popular supported 42 * libraries seems to be a good compromise. 43 * 44 * The early Boost implementation (http://www.boxbackup.org/trac/browser/box/nick/win/lib/win32/boost_1_32_0/libs/thread/src/condition.cpp?rev=30) 45 * is identical to pthreads-win32 (http://sourceware.org/cgi-bin/cvsweb.cgi/pthreads/pthread_cond_wait.c?rev=1.10&content-type=text/x-cvsweb-markup&cvsroot=pthreads-win32). 46 * Current Boost uses yet another (although seemingly equivalent) algorithm which came from their 'thread rewrite' effort. 47 * 48 * This file includes timedWait/signal/broadcast implementations translated to WebKit coding style from the latest algorithm by 49 * Alexander Terekhov and Louis Thomas, as captured here: http://sourceware.org/cgi-bin/cvsweb.cgi/pthreads/pthread_cond_wait.c?rev=1.10&content-type=text/x-cvsweb-markup&cvsroot=pthreads-win32 50 * It replaces the implementation of their previous algorithm, also documented in the same source above. 51 * The naming and comments are left very close to original to enable easy cross-check. 52 * 53 * The corresponding Pthreads-win32 License is included below, and CONTRIBUTORS file which it refers to is added to 54 * source directory (as CONTRIBUTORS.pthreads-win32). 55 */ 56 57 /* 58 * Pthreads-win32 - POSIX Threads Library for Win32 59 * Copyright(C) 1998 John E. Bossom 60 * Copyright(C) 1999,2005 Pthreads-win32 contributors 61 * 62 * Contact Email: rpj (at) callisto.canberra.edu.au 63 * 64 * The current list of contributors is contained 65 * in the file CONTRIBUTORS included with the source 66 * code distribution. The list can also be seen at the 67 * following World Wide Web location: 68 * http://sources.redhat.com/pthreads-win32/contributors.html 69 * 70 * This library is free software; you can redistribute it and/or 71 * modify it under the terms of the GNU Lesser General Public 72 * License as published by the Free Software Foundation; either 73 * version 2 of the License, or (at your option) any later version. 74 * 75 * This library is distributed in the hope that it will be useful, 76 * but WITHOUT ANY WARRANTY; without even the implied warranty of 77 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 78 * Lesser General Public License for more details. 79 * 80 * You should have received a copy of the GNU Lesser General Public 81 * License along with this library in the file COPYING.LIB; 82 * if not, write to the Free Software Foundation, Inc., 83 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA 84 */ 85 86 #include "config.h" 87 #include "Threading.h" 88 89 #include "MainThread.h" 90 #include "ThreadFunctionInvocation.h" 91 #include <windows.h> 92 #include <wtf/CurrentTime.h> 93 #include <wtf/HashMap.h> 94 #include <wtf/MathExtras.h> 95 #include <wtf/OwnPtr.h> 96 #include <wtf/PassOwnPtr.h> 97 #include <wtf/RandomNumberSeed.h> 98 99 #if !USE(PTHREADS) && OS(WINDOWS) 100 #include "ThreadSpecific.h" 101 #endif 102 103 #if !OS(WINCE) 104 #include <process.h> 105 #endif 106 107 #if HAVE(ERRNO_H) 108 #include <errno.h> 109 #endif 110 111 namespace WTF { 112 113 // MS_VC_EXCEPTION, THREADNAME_INFO, and setThreadNameInternal all come from <http://msdn.microsoft.com/en-us/library/xcb2z8hs.aspx>. 114 static const DWORD MS_VC_EXCEPTION = 0x406D1388; 115 116 #pragma pack(push, 8) 117 typedef struct tagTHREADNAME_INFO { 118 DWORD dwType; // must be 0x1000 119 LPCSTR szName; // pointer to name (in user addr space) 120 DWORD dwThreadID; // thread ID (-1=caller thread) 121 DWORD dwFlags; // reserved for future use, must be zero 122 } THREADNAME_INFO; 123 #pragma pack(pop) 124 125 void initializeCurrentThreadInternal(const char* szThreadName) 126 { 127 THREADNAME_INFO info; 128 info.dwType = 0x1000; 129 info.szName = szThreadName; 130 info.dwThreadID = GetCurrentThreadId(); 131 info.dwFlags = 0; 132 133 __try { 134 RaiseException(MS_VC_EXCEPTION, 0, sizeof(info)/sizeof(ULONG_PTR), reinterpret_cast<ULONG_PTR*>(&info)); 135 } __except (EXCEPTION_CONTINUE_EXECUTION) { 136 } 137 } 138 139 static Mutex* atomicallyInitializedStaticMutex; 140 141 void lockAtomicallyInitializedStaticMutex() 142 { 143 ASSERT(atomicallyInitializedStaticMutex); 144 atomicallyInitializedStaticMutex->lock(); 145 } 146 147 void unlockAtomicallyInitializedStaticMutex() 148 { 149 atomicallyInitializedStaticMutex->unlock(); 150 } 151 152 static Mutex& threadMapMutex() 153 { 154 static Mutex mutex; 155 return mutex; 156 } 157 158 void initializeThreading() 159 { 160 if (atomicallyInitializedStaticMutex) 161 return; 162 163 atomicallyInitializedStaticMutex = new Mutex; 164 threadMapMutex(); 165 initializeRandomNumberGenerator(); 166 } 167 168 static HashMap<DWORD, HANDLE>& threadMap() 169 { 170 static HashMap<DWORD, HANDLE> map; 171 return map; 172 } 173 174 static void storeThreadHandleByIdentifier(DWORD threadID, HANDLE threadHandle) 175 { 176 MutexLocker locker(threadMapMutex()); 177 ASSERT(!threadMap().contains(threadID)); 178 threadMap().add(threadID, threadHandle); 179 } 180 181 static HANDLE threadHandleForIdentifier(ThreadIdentifier id) 182 { 183 MutexLocker locker(threadMapMutex()); 184 return threadMap().get(id); 185 } 186 187 static void clearThreadHandleForIdentifier(ThreadIdentifier id) 188 { 189 MutexLocker locker(threadMapMutex()); 190 ASSERT(threadMap().contains(id)); 191 threadMap().remove(id); 192 } 193 194 static unsigned __stdcall wtfThreadEntryPoint(void* param) 195 { 196 OwnPtr<ThreadFunctionInvocation> invocation = adoptPtr(static_cast<ThreadFunctionInvocation*>(param)); 197 void* result = invocation->function(invocation->data); 198 199 #if !USE(PTHREADS) && OS(WINDOWS) 200 // Do the TLS cleanup. 201 ThreadSpecificThreadExit(); 202 #endif 203 204 return reinterpret_cast<unsigned>(result); 205 } 206 207 ThreadIdentifier createThreadInternal(ThreadFunction entryPoint, void* data, const char* threadName) 208 { 209 unsigned threadIdentifier = 0; 210 ThreadIdentifier threadID = 0; 211 OwnPtr<ThreadFunctionInvocation> invocation = adoptPtr(new ThreadFunctionInvocation(entryPoint, data)); 212 #if OS(WINCE) 213 // This is safe on WINCE, since CRT is in the core and innately multithreaded. 214 // On desktop Windows, need to use _beginthreadex (not available on WinCE) if using any CRT functions 215 HANDLE threadHandle = CreateThread(0, 0, (LPTHREAD_START_ROUTINE)wtfThreadEntryPoint, invocation.get(), 0, (LPDWORD)&threadIdentifier); 216 #else 217 HANDLE threadHandle = reinterpret_cast<HANDLE>(_beginthreadex(0, 0, wtfThreadEntryPoint, invocation.get(), 0, &threadIdentifier)); 218 #endif 219 if (!threadHandle) { 220 #if OS(WINCE) 221 LOG_ERROR("Failed to create thread at entry point %p with data %p: %ld", entryPoint, data, ::GetLastError()); 222 #elif !HAVE(ERRNO_H) 223 LOG_ERROR("Failed to create thread at entry point %p with data %p.", entryPoint, data); 224 #else 225 LOG_ERROR("Failed to create thread at entry point %p with data %p: %ld", entryPoint, data, errno); 226 #endif 227 return 0; 228 } 229 230 // The thread will take ownership of invocation. 231 invocation.leakPtr(); 232 233 threadID = static_cast<ThreadIdentifier>(threadIdentifier); 234 storeThreadHandleByIdentifier(threadIdentifier, threadHandle); 235 236 return threadID; 237 } 238 239 int waitForThreadCompletion(ThreadIdentifier threadID, void** result) 240 { 241 ASSERT(threadID); 242 243 HANDLE threadHandle = threadHandleForIdentifier(threadID); 244 if (!threadHandle) 245 LOG_ERROR("ThreadIdentifier %u did not correspond to an active thread when trying to quit", threadID); 246 247 DWORD joinResult = WaitForSingleObject(threadHandle, INFINITE); 248 if (joinResult == WAIT_FAILED) 249 LOG_ERROR("ThreadIdentifier %u was found to be deadlocked trying to quit", threadID); 250 251 CloseHandle(threadHandle); 252 clearThreadHandleForIdentifier(threadID); 253 254 return joinResult; 255 } 256 257 void detachThread(ThreadIdentifier threadID) 258 { 259 ASSERT(threadID); 260 261 HANDLE threadHandle = threadHandleForIdentifier(threadID); 262 if (threadHandle) 263 CloseHandle(threadHandle); 264 clearThreadHandleForIdentifier(threadID); 265 } 266 267 void yield() 268 { 269 ::Sleep(1); 270 } 271 272 ThreadIdentifier currentThread() 273 { 274 return static_cast<ThreadIdentifier>(GetCurrentThreadId()); 275 } 276 277 Mutex::Mutex() 278 { 279 m_mutex.m_recursionCount = 0; 280 InitializeCriticalSection(&m_mutex.m_internalMutex); 281 } 282 283 Mutex::~Mutex() 284 { 285 DeleteCriticalSection(&m_mutex.m_internalMutex); 286 } 287 288 void Mutex::lock() 289 { 290 EnterCriticalSection(&m_mutex.m_internalMutex); 291 ++m_mutex.m_recursionCount; 292 } 293 294 bool Mutex::tryLock() 295 { 296 // This method is modeled after the behavior of pthread_mutex_trylock, 297 // which will return an error if the lock is already owned by the 298 // current thread. Since the primitive Win32 'TryEnterCriticalSection' 299 // treats this as a successful case, it changes the behavior of several 300 // tests in WebKit that check to see if the current thread already 301 // owned this mutex (see e.g., IconDatabase::getOrCreateIconRecord) 302 DWORD result = TryEnterCriticalSection(&m_mutex.m_internalMutex); 303 304 if (result != 0) { // We got the lock 305 // If this thread already had the lock, we must unlock and 306 // return false so that we mimic the behavior of POSIX's 307 // pthread_mutex_trylock: 308 if (m_mutex.m_recursionCount > 0) { 309 LeaveCriticalSection(&m_mutex.m_internalMutex); 310 return false; 311 } 312 313 ++m_mutex.m_recursionCount; 314 return true; 315 } 316 317 return false; 318 } 319 320 void Mutex::unlock() 321 { 322 --m_mutex.m_recursionCount; 323 LeaveCriticalSection(&m_mutex.m_internalMutex); 324 } 325 326 bool PlatformCondition::timedWait(PlatformMutex& mutex, DWORD durationMilliseconds) 327 { 328 // Enter the wait state. 329 DWORD res = WaitForSingleObject(m_blockLock, INFINITE); 330 ASSERT(res == WAIT_OBJECT_0); 331 ++m_waitersBlocked; 332 res = ReleaseSemaphore(m_blockLock, 1, 0); 333 ASSERT(res); 334 335 --mutex.m_recursionCount; 336 LeaveCriticalSection(&mutex.m_internalMutex); 337 338 // Main wait - use timeout. 339 bool timedOut = (WaitForSingleObject(m_blockQueue, durationMilliseconds) == WAIT_TIMEOUT); 340 341 res = WaitForSingleObject(m_unblockLock, INFINITE); 342 ASSERT(res == WAIT_OBJECT_0); 343 344 int signalsLeft = m_waitersToUnblock; 345 346 if (m_waitersToUnblock) 347 --m_waitersToUnblock; 348 else if (++m_waitersGone == (INT_MAX / 2)) { // timeout/canceled or spurious semaphore 349 // timeout or spurious wakeup occured, normalize the m_waitersGone count 350 // this may occur if many calls to wait with a timeout are made and 351 // no call to notify_* is made 352 res = WaitForSingleObject(m_blockLock, INFINITE); 353 ASSERT(res == WAIT_OBJECT_0); 354 m_waitersBlocked -= m_waitersGone; 355 res = ReleaseSemaphore(m_blockLock, 1, 0); 356 ASSERT(res); 357 m_waitersGone = 0; 358 } 359 360 res = ReleaseMutex(m_unblockLock); 361 ASSERT(res); 362 363 if (signalsLeft == 1) { 364 res = ReleaseSemaphore(m_blockLock, 1, 0); // Open the gate. 365 ASSERT(res); 366 } 367 368 EnterCriticalSection (&mutex.m_internalMutex); 369 ++mutex.m_recursionCount; 370 371 return !timedOut; 372 } 373 374 void PlatformCondition::signal(bool unblockAll) 375 { 376 unsigned signalsToIssue = 0; 377 378 DWORD res = WaitForSingleObject(m_unblockLock, INFINITE); 379 ASSERT(res == WAIT_OBJECT_0); 380 381 if (m_waitersToUnblock) { // the gate is already closed 382 if (!m_waitersBlocked) { // no-op 383 res = ReleaseMutex(m_unblockLock); 384 ASSERT(res); 385 return; 386 } 387 388 if (unblockAll) { 389 signalsToIssue = m_waitersBlocked; 390 m_waitersToUnblock += m_waitersBlocked; 391 m_waitersBlocked = 0; 392 } else { 393 signalsToIssue = 1; 394 ++m_waitersToUnblock; 395 --m_waitersBlocked; 396 } 397 } else if (m_waitersBlocked > m_waitersGone) { 398 res = WaitForSingleObject(m_blockLock, INFINITE); // Close the gate. 399 ASSERT(res == WAIT_OBJECT_0); 400 if (m_waitersGone != 0) { 401 m_waitersBlocked -= m_waitersGone; 402 m_waitersGone = 0; 403 } 404 if (unblockAll) { 405 signalsToIssue = m_waitersBlocked; 406 m_waitersToUnblock = m_waitersBlocked; 407 m_waitersBlocked = 0; 408 } else { 409 signalsToIssue = 1; 410 m_waitersToUnblock = 1; 411 --m_waitersBlocked; 412 } 413 } else { // No-op. 414 res = ReleaseMutex(m_unblockLock); 415 ASSERT(res); 416 return; 417 } 418 419 res = ReleaseMutex(m_unblockLock); 420 ASSERT(res); 421 422 if (signalsToIssue) { 423 res = ReleaseSemaphore(m_blockQueue, signalsToIssue, 0); 424 ASSERT(res); 425 } 426 } 427 428 static const long MaxSemaphoreCount = static_cast<long>(~0UL >> 1); 429 430 ThreadCondition::ThreadCondition() 431 { 432 m_condition.m_waitersGone = 0; 433 m_condition.m_waitersBlocked = 0; 434 m_condition.m_waitersToUnblock = 0; 435 m_condition.m_blockLock = CreateSemaphore(0, 1, 1, 0); 436 m_condition.m_blockQueue = CreateSemaphore(0, 0, MaxSemaphoreCount, 0); 437 m_condition.m_unblockLock = CreateMutex(0, 0, 0); 438 439 if (!m_condition.m_blockLock || !m_condition.m_blockQueue || !m_condition.m_unblockLock) { 440 if (m_condition.m_blockLock) 441 CloseHandle(m_condition.m_blockLock); 442 if (m_condition.m_blockQueue) 443 CloseHandle(m_condition.m_blockQueue); 444 if (m_condition.m_unblockLock) 445 CloseHandle(m_condition.m_unblockLock); 446 } 447 } 448 449 ThreadCondition::~ThreadCondition() 450 { 451 CloseHandle(m_condition.m_blockLock); 452 CloseHandle(m_condition.m_blockQueue); 453 CloseHandle(m_condition.m_unblockLock); 454 } 455 456 void ThreadCondition::wait(Mutex& mutex) 457 { 458 m_condition.timedWait(mutex.impl(), INFINITE); 459 } 460 461 bool ThreadCondition::timedWait(Mutex& mutex, double absoluteTime) 462 { 463 DWORD interval = absoluteTimeToWaitTimeoutInterval(absoluteTime); 464 465 if (!interval) { 466 // Consider the wait to have timed out, even if our condition has already been signaled, to 467 // match the pthreads implementation. 468 return false; 469 } 470 471 return m_condition.timedWait(mutex.impl(), interval); 472 } 473 474 void ThreadCondition::signal() 475 { 476 m_condition.signal(false); // Unblock only 1 thread. 477 } 478 479 void ThreadCondition::broadcast() 480 { 481 m_condition.signal(true); // Unblock all threads. 482 } 483 484 DWORD absoluteTimeToWaitTimeoutInterval(double absoluteTime) 485 { 486 double currentTime = WTF::currentTime(); 487 488 // Time is in the past - return immediately. 489 if (absoluteTime < currentTime) 490 return 0; 491 492 // Time is too far in the future (and would overflow unsigned long) - wait forever. 493 if (absoluteTime - currentTime > static_cast<double>(INT_MAX) / 1000.0) 494 return INFINITE; 495 496 return static_cast<DWORD>((absoluteTime - currentTime) * 1000.0); 497 } 498 499 } // namespace WTF 500