wtf/ThreadingWin.cpp

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