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 setThreadName 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 static void setThreadName(DWORD dwThreadID, LPCSTR szThreadName)
 114 {
 115     // Visual Studio has a 31-character limit on thread names. Longer names will
 116     // be truncated silently, but we'd like callers to know about the limit.
 117     ASSERT_ARG(szThreadName, strlen(szThreadName) <= 31);
 118
 119     THREADNAME_INFO info;
 120     info.dwType = 0x1000;
 121     info.szName = szThreadName;
 122     info.dwThreadID = dwThreadID;
 123     info.dwFlags = 0;
 124
 125     __try {
 126         RaiseException(MS_VC_EXCEPTION, 0, sizeof(info)/sizeof(ULONG_PTR), reinterpret_cast<ULONG_PTR*>(&info));
 127     } __except (EXCEPTION_CONTINUE_EXECUTION) {
 128     }
 129 }
 130
 131 static Mutex* atomicallyInitializedStaticMutex;
 132
 133 void lockAtomicallyInitializedStaticMutex()
 134 {
 135     ASSERT(atomicallyInitializedStaticMutex);
 136     atomicallyInitializedStaticMutex->lock();
 137 }
 138
 139 void unlockAtomicallyInitializedStaticMutex()
 140 {
 141     atomicallyInitializedStaticMutex->unlock();
 142 }
 143
 144 static ThreadIdentifier mainThreadIdentifier;
 145
 146 static Mutex& threadMapMutex()
 147 {
 148     static Mutex mutex;
 149     return mutex;
 150 }
 151
 152 void initializeThreading()
 153 {
 154     if (!atomicallyInitializedStaticMutex) {
 155         atomicallyInitializedStaticMutex = new Mutex;
 156         threadMapMutex();
 157         initializeRandomNumberGenerator();
 158         initializeMainThread();
 159         mainThreadIdentifier = currentThread();
 160         setThreadName(mainThreadIdentifier, "Main Thread");
 161     }
 162 }
 163
 164 static HashMap<DWORD, HANDLE>& threadMap()
 165 {
 166     static HashMap<DWORD, HANDLE> map;
 167     return map;
 168 }
 169
 170 static void storeThreadHandleByIdentifier(DWORD threadID, HANDLE threadHandle)
 171 {
 172     MutexLocker locker(threadMapMutex());
 173     ASSERT(!threadMap().contains(threadID));
 174     threadMap().add(threadID, threadHandle);
 175 }
 176
 177 static HANDLE threadHandleForIdentifier(ThreadIdentifier id)
 178 {
 179     MutexLocker locker(threadMapMutex());
 180     return threadMap().get(id);
 181 }
 182
 183 static void clearThreadHandleForIdentifier(ThreadIdentifier id)
 184 {
 185     MutexLocker locker(threadMapMutex());
 186     ASSERT(threadMap().contains(id));
 187     threadMap().remove(id);
 188 }
 189
 190 struct ThreadFunctionInvocation {
 191     ThreadFunctionInvocation(ThreadFunction function, void* data) : function(function), data(data) {}
 192
 193     ThreadFunction function;
 194     void* data;
 195 };
 196
 197 static unsigned __stdcall wtfThreadEntryPoint(void* param)
 198 {
 199     ThreadFunctionInvocation invocation = *static_cast<ThreadFunctionInvocation*>(param);
 200     delete static_cast<ThreadFunctionInvocation*>(param);
 201
 202     void* result = invocation.function(invocation.data);
 203
 204 #if !USE(PTHREADS) && PLATFORM(WIN_OS)
 205     // Do the TLS cleanup.
 206     ThreadSpecificThreadExit();
 207 #endif
 208
 209     return reinterpret_cast<unsigned>(result);
 210 }
 211
 212 ThreadIdentifier createThreadInternal(ThreadFunction entryPoint, void* data, const char* threadName)
 213 {
 214     unsigned threadIdentifier = 0;
 215     ThreadIdentifier threadID = 0;
 216     ThreadFunctionInvocation* invocation = new ThreadFunctionInvocation(entryPoint, data);
 217     HANDLE threadHandle = reinterpret_cast<HANDLE>(_beginthreadex(0, 0, wtfThreadEntryPoint, invocation, 0, &threadIdentifier));
 218     if (!threadHandle) {
 219         LOG_ERROR("Failed to create thread at entry point %p with data %p: %ld", entryPoint, data, errno);
 220         return 0;
 221     }
 222
 223     if (threadName)
 224         setThreadName(threadIdentifier, threadName);
 225
 226     threadID = static_cast<ThreadIdentifier>(threadIdentifier);
 227     storeThreadHandleByIdentifier(threadIdentifier, threadHandle);
 228
 229     return threadID;
 230 }
 231
 232 int waitForThreadCompletion(ThreadIdentifier threadID, void** result)
 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 ThreadIdentifier currentThread()
 261 {
 262     return static_cast<ThreadIdentifier>(GetCurrentThreadId());
 263 }
 264
 265 bool isMainThread()
 266 {
 267     return currentThread() == mainThreadIdentifier;
 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     --m_mutex.m_recursionCount;
 316     LeaveCriticalSection(&m_mutex.m_internalMutex);
 317 }
 318
 319 bool PlatformCondition::timedWait(PlatformMutex& mutex, DWORD durationMilliseconds)
 320 {
 321     // Enter the wait state.
 322     DWORD res = WaitForSingleObject(m_blockLock, INFINITE);
 323     ASSERT(res == WAIT_OBJECT_0);
 324     ++m_waitersBlocked;
 325     res = ReleaseSemaphore(m_blockLock, 1, 0);
 326     ASSERT(res);
 327
 328     LeaveCriticalSection(&mutex.m_internalMutex);
 329
 330     // Main wait - use timeout.
 331     bool timedOut = (WaitForSingleObject(m_blockQueue, durationMilliseconds) == WAIT_TIMEOUT);
 332
 333     res = WaitForSingleObject(m_unblockLock, INFINITE);
 334     ASSERT(res == WAIT_OBJECT_0);
 335
 336     int signalsLeft = m_waitersToUnblock;
 337
 338     if (m_waitersToUnblock)
 339         --m_waitersToUnblock;
 340     else if (++m_waitersGone == (INT_MAX / 2)) { // timeout/canceled or spurious semaphore
 341         // timeout or spurious wakeup occured, normalize the m_waitersGone count
 342         // this may occur if many calls to wait with a timeout are made and
 343         // no call to notify_* is made
 344         res = WaitForSingleObject(m_blockLock, INFINITE);
 345         ASSERT(res == WAIT_OBJECT_0);
 346         m_waitersBlocked -= m_waitersGone;
 347         res = ReleaseSemaphore(m_blockLock, 1, 0);
 348         ASSERT(res);
 349         m_waitersGone = 0;
 350     }
 351
 352     res = ReleaseMutex(m_unblockLock);
 353     ASSERT(res);
 354
 355     if (signalsLeft == 1) {
 356         res = ReleaseSemaphore(m_blockLock, 1, 0); // Open the gate.
 357         ASSERT(res);
 358     }
 359
 360     EnterCriticalSection (&mutex.m_internalMutex);
 361
 362     return !timedOut;
 363 }
 364
 365 void PlatformCondition::signal(bool unblockAll)
 366 {
 367     unsigned signalsToIssue = 0;
 368
 369     DWORD res = WaitForSingleObject(m_unblockLock, INFINITE);
 370     ASSERT(res == WAIT_OBJECT_0);
 371
 372     if (m_waitersToUnblock) { // the gate is already closed
 373         if (!m_waitersBlocked) { // no-op
 374             res = ReleaseMutex(m_unblockLock);
 375             ASSERT(res);
 376             return;
 377         }
 378
 379         if (unblockAll) {
 380             signalsToIssue = m_waitersBlocked;
 381             m_waitersToUnblock += m_waitersBlocked;
 382             m_waitersBlocked = 0;
 383         } else {
 384             signalsToIssue = 1;
 385             ++m_waitersToUnblock;
 386             --m_waitersBlocked;
 387         }
 388     } else if (m_waitersBlocked > m_waitersGone) {
 389         res = WaitForSingleObject(m_blockLock, INFINITE); // Close the gate.
 390         ASSERT(res == WAIT_OBJECT_0);
 391         if (m_waitersGone != 0) {
 392             m_waitersBlocked -= m_waitersGone;
 393             m_waitersGone = 0;
 394         }
 395         if (unblockAll) {
 396             signalsToIssue = m_waitersBlocked;
 397             m_waitersToUnblock = m_waitersBlocked;
 398             m_waitersBlocked = 0;
 399         } else {
 400             signalsToIssue = 1;
 401             m_waitersToUnblock = 1;
 402             --m_waitersBlocked;
 403         }
 404     } else { // No-op.
 405         res = ReleaseMutex(m_unblockLock);
 406         ASSERT(res);
 407         return;
 408     }
 409
 410     res = ReleaseMutex(m_unblockLock);
 411     ASSERT(res);
 412
 413     if (signalsToIssue) {
 414         res = ReleaseSemaphore(m_blockQueue, signalsToIssue, 0);
 415         ASSERT(res);
 416     }
 417 }
 418
 419 static const long MaxSemaphoreCount = static_cast<long>(~0UL >> 1);
 420
 421 ThreadCondition::ThreadCondition()
 422 {
 423     m_condition.m_waitersGone = 0;
 424     m_condition.m_waitersBlocked = 0;
 425     m_condition.m_waitersToUnblock = 0;
 426     m_condition.m_blockLock = CreateSemaphore(0, 1, 1, 0);
 427     m_condition.m_blockQueue = CreateSemaphore(0, 0, MaxSemaphoreCount, 0);
 428     m_condition.m_unblockLock = CreateMutex(0, 0, 0);
 429
 430     if (!m_condition.m_blockLock || !m_condition.m_blockQueue || !m_condition.m_unblockLock) {
 431         if (m_condition.m_blockLock)
 432             CloseHandle(m_condition.m_blockLock);
 433         if (m_condition.m_blockQueue)
 434             CloseHandle(m_condition.m_blockQueue);
 435         if (m_condition.m_unblockLock)
 436             CloseHandle(m_condition.m_unblockLock);
 437     }
 438 }
 439
 440 ThreadCondition::~ThreadCondition()
 441 {
 442     CloseHandle(m_condition.m_blockLock);
 443     CloseHandle(m_condition.m_blockQueue);
 444     CloseHandle(m_condition.m_unblockLock);
 445 }
 446
 447 void ThreadCondition::wait(Mutex& mutex)
 448 {
 449     m_condition.timedWait(mutex.impl(), INFINITE);
 450 }
 451
 452 bool ThreadCondition::timedWait(Mutex& mutex, double absoluteTime)
 453 {
 454     double currentTime = WTF::currentTime();
 455
 456     // Time is in the past - return immediately.
 457     if (absoluteTime < currentTime)
 458         return false;
 459
 460     double intervalMilliseconds = (absoluteTime - currentTime) * 1000.0;
 461     if (intervalMilliseconds >= INT_MAX)
 462         intervalMilliseconds = INT_MAX;
 463
 464     return m_condition.timedWait(mutex.impl(), static_cast<unsigned long>(intervalMilliseconds));
 465 }
 466
 467 void ThreadCondition::signal()
 468 {
 469     m_condition.signal(false); // Unblock only 1 thread.
 470 }
 471
 472 void ThreadCondition::broadcast()
 473 {
 474     m_condition.signal(true); // Unblock all threads.
 475 }
 476
 477 } // namespace WTF