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 #if OS(WINDOWS) 90 91 #include "DateMath.h" 92 #include "dtoa.h" 93 #include "dtoa/cached-powers.h" 94 95 #include "MainThread.h" 96 #include "ThreadFunctionInvocation.h" 97 #include "ThreadSpecific.h" 98 #include <windows.h> 99 #include "wtf/CurrentTime.h" 100 #include "wtf/HashMap.h" 101 #include "wtf/MathExtras.h" 102 #include "wtf/OwnPtr.h" 103 #include "wtf/PassOwnPtr.h" 104 #include "wtf/RandomNumberSeed.h" 105 #include "wtf/WTFThreadData.h" 106 107 #include <errno.h> 108 #include <process.h> 109 110 namespace WTF { 111 112 // MS_VC_EXCEPTION, THREADNAME_INFO, and setThreadNameInternal all come from <http://msdn.microsoft.com/en-us/library/xcb2z8hs.aspx>. 113 static const DWORD MS_VC_EXCEPTION = 0x406D1388; 114 115 #pragma pack(push, 8) 116 typedef struct tagTHREADNAME_INFO { 117 DWORD dwType; // must be 0x1000 118 LPCSTR szName; // pointer to name (in user addr space) 119 DWORD dwThreadID; // thread ID (-1=caller thread) 120 DWORD dwFlags; // reserved for future use, must be zero 121 } THREADNAME_INFO; 122 #pragma pack(pop) 123 124 void initializeCurrentThreadInternal(const char* szThreadName) 125 { 126 THREADNAME_INFO info; 127 info.dwType = 0x1000; 128 info.szName = szThreadName; 129 info.dwThreadID = GetCurrentThreadId(); 130 info.dwFlags = 0; 131 132 __try { 133 RaiseException(MS_VC_EXCEPTION, 0, sizeof(info)/sizeof(ULONG_PTR), reinterpret_cast<ULONG_PTR*>(&info)); 134 } __except (EXCEPTION_CONTINUE_EXECUTION) { 135 } 136 } 137 138 static Mutex* atomicallyInitializedStaticMutex; 139 140 void lockAtomicallyInitializedStaticMutex() 141 { 142 ASSERT(atomicallyInitializedStaticMutex); 143 atomicallyInitializedStaticMutex->lock(); 144 } 145 146 void unlockAtomicallyInitializedStaticMutex() 147 { 148 atomicallyInitializedStaticMutex->unlock(); 149 } 150 151 static Mutex& threadMapMutex() 152 { 153 static Mutex mutex; 154 return mutex; 155 } 156 157 void initializeThreading() 158 { 159 // This should only be called once. 160 ASSERT(!atomicallyInitializedStaticMutex); 161 162 WTF::double_conversion::initialize(); 163 // StringImpl::empty() does not construct its static string in a threadsafe fashion, 164 // so ensure it has been initialized from here. 165 StringImpl::empty(); 166 atomicallyInitializedStaticMutex = new Mutex; 167 threadMapMutex(); 168 initializeRandomNumberGenerator(); 169 wtfThreadData(); 170 s_dtoaP5Mutex = new Mutex; 171 initializeDates(); 172 } 173 174 static HashMap<DWORD, HANDLE>& threadMap() 175 { 176 static HashMap<DWORD, HANDLE> map; 177 return map; 178 } 179 180 static void storeThreadHandleByIdentifier(DWORD threadID, HANDLE threadHandle) 181 { 182 MutexLocker locker(threadMapMutex()); 183 ASSERT(!threadMap().contains(threadID)); 184 threadMap().add(threadID, threadHandle); 185 } 186 187 static HANDLE threadHandleForIdentifier(ThreadIdentifier id) 188 { 189 MutexLocker locker(threadMapMutex()); 190 return threadMap().get(id); 191 } 192 193 static void clearThreadHandleForIdentifier(ThreadIdentifier id) 194 { 195 MutexLocker locker(threadMapMutex()); 196 ASSERT(threadMap().contains(id)); 197 threadMap().remove(id); 198 } 199 200 static unsigned __stdcall wtfThreadEntryPoint(void* param) 201 { 202 OwnPtr<ThreadFunctionInvocation> invocation = adoptPtr(static_cast<ThreadFunctionInvocation*>(param)); 203 invocation->function(invocation->data); 204 205 // Do the TLS cleanup. 206 ThreadSpecificThreadExit(); 207 208 return 0; 209 } 210 211 ThreadIdentifier createThreadInternal(ThreadFunction entryPoint, void* data, const char* threadName) 212 { 213 unsigned threadIdentifier = 0; 214 ThreadIdentifier threadID = 0; 215 OwnPtr<ThreadFunctionInvocation> invocation = adoptPtr(new ThreadFunctionInvocation(entryPoint, data)); 216 HANDLE threadHandle = reinterpret_cast<HANDLE>(_beginthreadex(0, 0, wtfThreadEntryPoint, invocation.get(), 0, &threadIdentifier)); 217 if (!threadHandle) { 218 LOG_ERROR("Failed to create thread at entry point %p with data %p: %ld", entryPoint, data, errno); 219 return 0; 220 } 221 222 // The thread will take ownership of invocation. 223 ThreadFunctionInvocation* leakedInvocation = invocation.leakPtr(); 224 UNUSED_PARAM(leakedInvocation); 225 226 threadID = static_cast<ThreadIdentifier>(threadIdentifier); 227 storeThreadHandleByIdentifier(threadIdentifier, threadHandle); 228 229 return threadID; 230 } 231 232 int waitForThreadCompletion(ThreadIdentifier threadID) 233 { 234 ASSERT(threadID); 235 236 HANDLE threadHandle = threadHandleForIdentifier(threadID); 237 if (!threadHandle) 238 LOG_ERROR("ThreadIdentifier %u did not correspond to an active thread when trying to quit", threadID); 239 240 DWORD joinResult = WaitForSingleObject(threadHandle, INFINITE); 241 if (joinResult == WAIT_FAILED) 242 LOG_ERROR("ThreadIdentifier %u was found to be deadlocked trying to quit", threadID); 243 244 CloseHandle(threadHandle); 245 clearThreadHandleForIdentifier(threadID); 246 247 return joinResult; 248 } 249 250 void detachThread(ThreadIdentifier threadID) 251 { 252 ASSERT(threadID); 253 254 HANDLE threadHandle = threadHandleForIdentifier(threadID); 255 if (threadHandle) 256 CloseHandle(threadHandle); 257 clearThreadHandleForIdentifier(threadID); 258 } 259 260 void yield() 261 { 262 ::Sleep(1); 263 } 264 265 ThreadIdentifier currentThread() 266 { 267 return static_cast<ThreadIdentifier>(GetCurrentThreadId()); 268 } 269 270 Mutex::Mutex() 271 { 272 m_mutex.m_recursionCount = 0; 273 InitializeCriticalSection(&m_mutex.m_internalMutex); 274 } 275 276 Mutex::~Mutex() 277 { 278 DeleteCriticalSection(&m_mutex.m_internalMutex); 279 } 280 281 void Mutex::lock() 282 { 283 EnterCriticalSection(&m_mutex.m_internalMutex); 284 ++m_mutex.m_recursionCount; 285 } 286 287 bool Mutex::tryLock() 288 { 289 // This method is modeled after the behavior of pthread_mutex_trylock, 290 // which will return an error if the lock is already owned by the 291 // current thread. Since the primitive Win32 'TryEnterCriticalSection' 292 // treats this as a successful case, it changes the behavior of several 293 // tests in WebKit that check to see if the current thread already 294 // owned this mutex (see e.g., IconDatabase::getOrCreateIconRecord) 295 DWORD result = TryEnterCriticalSection(&m_mutex.m_internalMutex); 296 297 if (result != 0) { // We got the lock 298 // If this thread already had the lock, we must unlock and 299 // return false so that we mimic the behavior of POSIX's 300 // pthread_mutex_trylock: 301 if (m_mutex.m_recursionCount > 0) { 302 LeaveCriticalSection(&m_mutex.m_internalMutex); 303 return false; 304 } 305 306 ++m_mutex.m_recursionCount; 307 return true; 308 } 309 310 return false; 311 } 312 313 void Mutex::unlock() 314 { 315 ASSERT(m_mutex.m_recursionCount); 316 --m_mutex.m_recursionCount; 317 LeaveCriticalSection(&m_mutex.m_internalMutex); 318 } 319 320 bool PlatformCondition::timedWait(PlatformMutex& mutex, DWORD durationMilliseconds) 321 { 322 // Enter the wait state. 323 DWORD res = WaitForSingleObject(m_blockLock, INFINITE); 324 ASSERT_UNUSED(res, res == WAIT_OBJECT_0); 325 ++m_waitersBlocked; 326 res = ReleaseSemaphore(m_blockLock, 1, 0); 327 ASSERT_UNUSED(res, res); 328 329 --mutex.m_recursionCount; 330 LeaveCriticalSection(&mutex.m_internalMutex); 331 332 // Main wait - use timeout. 333 bool timedOut = (WaitForSingleObject(m_blockQueue, durationMilliseconds) == WAIT_TIMEOUT); 334 335 res = WaitForSingleObject(m_unblockLock, INFINITE); 336 ASSERT_UNUSED(res, res == WAIT_OBJECT_0); 337 338 int signalsLeft = m_waitersToUnblock; 339 340 if (m_waitersToUnblock) 341 --m_waitersToUnblock; 342 else if (++m_waitersGone == (INT_MAX / 2)) { // timeout/canceled or spurious semaphore 343 // timeout or spurious wakeup occured, normalize the m_waitersGone count 344 // this may occur if many calls to wait with a timeout are made and 345 // no call to notify_* is made 346 res = WaitForSingleObject(m_blockLock, INFINITE); 347 ASSERT_UNUSED(res, res == WAIT_OBJECT_0); 348 m_waitersBlocked -= m_waitersGone; 349 res = ReleaseSemaphore(m_blockLock, 1, 0); 350 ASSERT_UNUSED(res, res); 351 m_waitersGone = 0; 352 } 353 354 res = ReleaseMutex(m_unblockLock); 355 ASSERT_UNUSED(res, res); 356 357 if (signalsLeft == 1) { 358 res = ReleaseSemaphore(m_blockLock, 1, 0); // Open the gate. 359 ASSERT_UNUSED(res, res); 360 } 361 362 EnterCriticalSection (&mutex.m_internalMutex); 363 ++mutex.m_recursionCount; 364 365 return !timedOut; 366 } 367 368 void PlatformCondition::signal(bool unblockAll) 369 { 370 unsigned signalsToIssue = 0; 371 372 DWORD res = WaitForSingleObject(m_unblockLock, INFINITE); 373 ASSERT_UNUSED(res, res == WAIT_OBJECT_0); 374 375 if (m_waitersToUnblock) { // the gate is already closed 376 if (!m_waitersBlocked) { // no-op 377 res = ReleaseMutex(m_unblockLock); 378 ASSERT_UNUSED(res, res); 379 return; 380 } 381 382 if (unblockAll) { 383 signalsToIssue = m_waitersBlocked; 384 m_waitersToUnblock += m_waitersBlocked; 385 m_waitersBlocked = 0; 386 } else { 387 signalsToIssue = 1; 388 ++m_waitersToUnblock; 389 --m_waitersBlocked; 390 } 391 } else if (m_waitersBlocked > m_waitersGone) { 392 res = WaitForSingleObject(m_blockLock, INFINITE); // Close the gate. 393 ASSERT_UNUSED(res, res == WAIT_OBJECT_0); 394 if (m_waitersGone != 0) { 395 m_waitersBlocked -= m_waitersGone; 396 m_waitersGone = 0; 397 } 398 if (unblockAll) { 399 signalsToIssue = m_waitersBlocked; 400 m_waitersToUnblock = m_waitersBlocked; 401 m_waitersBlocked = 0; 402 } else { 403 signalsToIssue = 1; 404 m_waitersToUnblock = 1; 405 --m_waitersBlocked; 406 } 407 } else { // No-op. 408 res = ReleaseMutex(m_unblockLock); 409 ASSERT_UNUSED(res, res); 410 return; 411 } 412 413 res = ReleaseMutex(m_unblockLock); 414 ASSERT_UNUSED(res, res); 415 416 if (signalsToIssue) { 417 res = ReleaseSemaphore(m_blockQueue, signalsToIssue, 0); 418 ASSERT_UNUSED(res, res); 419 } 420 } 421 422 static const long MaxSemaphoreCount = static_cast<long>(~0UL >> 1); 423 424 ThreadCondition::ThreadCondition() 425 { 426 m_condition.m_waitersGone = 0; 427 m_condition.m_waitersBlocked = 0; 428 m_condition.m_waitersToUnblock = 0; 429 m_condition.m_blockLock = CreateSemaphore(0, 1, 1, 0); 430 m_condition.m_blockQueue = CreateSemaphore(0, 0, MaxSemaphoreCount, 0); 431 m_condition.m_unblockLock = CreateMutex(0, 0, 0); 432 433 if (!m_condition.m_blockLock || !m_condition.m_blockQueue || !m_condition.m_unblockLock) { 434 if (m_condition.m_blockLock) 435 CloseHandle(m_condition.m_blockLock); 436 if (m_condition.m_blockQueue) 437 CloseHandle(m_condition.m_blockQueue); 438 if (m_condition.m_unblockLock) 439 CloseHandle(m_condition.m_unblockLock); 440 } 441 } 442 443 ThreadCondition::~ThreadCondition() 444 { 445 CloseHandle(m_condition.m_blockLock); 446 CloseHandle(m_condition.m_blockQueue); 447 CloseHandle(m_condition.m_unblockLock); 448 } 449 450 void ThreadCondition::wait(Mutex& mutex) 451 { 452 m_condition.timedWait(mutex.impl(), INFINITE); 453 } 454 455 bool ThreadCondition::timedWait(Mutex& mutex, double absoluteTime) 456 { 457 DWORD interval = absoluteTimeToWaitTimeoutInterval(absoluteTime); 458 459 if (!interval) { 460 // Consider the wait to have timed out, even if our condition has already been signaled, to 461 // match the pthreads implementation. 462 return false; 463 } 464 465 return m_condition.timedWait(mutex.impl(), interval); 466 } 467 468 void ThreadCondition::signal() 469 { 470 m_condition.signal(false); // Unblock only 1 thread. 471 } 472 473 void ThreadCondition::broadcast() 474 { 475 m_condition.signal(true); // Unblock all threads. 476 } 477 478 DWORD absoluteTimeToWaitTimeoutInterval(double absoluteTime) 479 { 480 double currentTime = WTF::currentTime(); 481 482 // Time is in the past - return immediately. 483 if (absoluteTime < currentTime) 484 return 0; 485 486 // Time is too far in the future (and would overflow unsigned long) - wait forever. 487 if (absoluteTime - currentTime > static_cast<double>(INT_MAX) / 1000.0) 488 return INFINITE; 489 490 return static_cast<DWORD>((absoluteTime - currentTime) * 1000.0); 491 } 492 493 } // namespace WTF 494 495 #endif // OS(WINDOWS) 496