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 #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