wtf/ThreadingWin.cpp

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