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.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
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.
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.
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/).
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.
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.
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.
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).
58 * Pthreads-win32 - POSIX Threads Library for Win32
59 * Copyright(C) 1998 John E. Bossom
60 * Copyright(C) 1999,2005 Pthreads-win32 contributors
62 * Contact Email: rpj@callisto.canberra.edu.au
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
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.
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.
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
87 #include "Threading.h"
90 #include "dtoa/cached-powers.h"
92 #include "MainThread.h"
93 #include "ThreadFunctionInvocation.h"
95 #include <wtf/CurrentTime.h>
96 #include <wtf/HashMap.h>
97 #include <wtf/MathExtras.h>
98 #include <wtf/OwnPtr.h>
99 #include <wtf/PassOwnPtr.h>
100 #include <wtf/RandomNumberSeed.h>
101 #include <wtf/WTFThreadData.h>
103 #if !USE(PTHREADS) && OS(WINDOWS)
104 #include "ThreadSpecific.h"
117 // MS_VC_EXCEPTION, THREADNAME_INFO, and setThreadNameInternal all come from <http://msdn.microsoft.com/en-us/library/xcb2z8hs.aspx>.
118 static const DWORD MS_VC_EXCEPTION = 0x406D1388;
120 #pragma pack(push, 8)
121 typedef struct tagTHREADNAME_INFO {
122 DWORD dwType; // must be 0x1000
123 LPCSTR szName; // pointer to name (in user addr space)
124 DWORD dwThreadID; // thread ID (-1=caller thread)
125 DWORD dwFlags; // reserved for future use, must be zero
129 void initializeCurrentThreadInternal(const char* szThreadName)
132 // FIXME: Implement thread name setting with MingW.
133 UNUSED_PARAM(szThreadName);
135 THREADNAME_INFO info;
136 info.dwType = 0x1000;
137 info.szName = szThreadName;
138 info.dwThreadID = GetCurrentThreadId();
142 RaiseException(MS_VC_EXCEPTION, 0, sizeof(info)/sizeof(ULONG_PTR), reinterpret_cast<ULONG_PTR*>(&info));
143 } __except (EXCEPTION_CONTINUE_EXECUTION) {
148 static Mutex* atomicallyInitializedStaticMutex;
150 void lockAtomicallyInitializedStaticMutex()
152 ASSERT(atomicallyInitializedStaticMutex);
153 atomicallyInitializedStaticMutex->lock();
156 void unlockAtomicallyInitializedStaticMutex()
158 atomicallyInitializedStaticMutex->unlock();
161 static Mutex& threadMapMutex()
167 void initializeThreading()
169 if (atomicallyInitializedStaticMutex)
172 WTF::double_conversion::initialize();
173 // StringImpl::empty() does not construct its static string in a threadsafe fashion,
174 // so ensure it has been initialized from here.
176 atomicallyInitializedStaticMutex = new Mutex;
178 initializeRandomNumberGenerator();
180 s_dtoaP5Mutex = new Mutex;
184 static HashMap<DWORD, HANDLE>& threadMap()
186 static HashMap<DWORD, HANDLE> map;
190 static void storeThreadHandleByIdentifier(DWORD threadID, HANDLE threadHandle)
192 MutexLocker locker(threadMapMutex());
193 ASSERT(!threadMap().contains(threadID));
194 threadMap().add(threadID, threadHandle);
197 static HANDLE threadHandleForIdentifier(ThreadIdentifier id)
199 MutexLocker locker(threadMapMutex());
200 return threadMap().get(id);
203 static void clearThreadHandleForIdentifier(ThreadIdentifier id)
205 MutexLocker locker(threadMapMutex());
206 ASSERT(threadMap().contains(id));
207 threadMap().remove(id);
210 static unsigned __stdcall wtfThreadEntryPoint(void* param)
212 OwnPtr<ThreadFunctionInvocation> invocation = adoptPtr(static_cast<ThreadFunctionInvocation*>(param));
213 invocation->function(invocation->data);
215 #if !USE(PTHREADS) && OS(WINDOWS)
216 // Do the TLS cleanup.
217 ThreadSpecificThreadExit();
223 ThreadIdentifier createThreadInternal(ThreadFunction entryPoint, void* data, const char* threadName)
225 unsigned threadIdentifier = 0;
226 ThreadIdentifier threadID = 0;
227 OwnPtr<ThreadFunctionInvocation> invocation = adoptPtr(new ThreadFunctionInvocation(entryPoint, data));
229 // This is safe on WINCE, since CRT is in the core and innately multithreaded.
230 // On desktop Windows, need to use _beginthreadex (not available on WinCE) if using any CRT functions
231 HANDLE threadHandle = CreateThread(0, 0, (LPTHREAD_START_ROUTINE)wtfThreadEntryPoint, invocation.get(), 0, (LPDWORD)&threadIdentifier);
233 HANDLE threadHandle = reinterpret_cast<HANDLE>(_beginthreadex(0, 0, wtfThreadEntryPoint, invocation.get(), 0, &threadIdentifier));
237 LOG_ERROR("Failed to create thread at entry point %p with data %p: %ld", entryPoint, data, ::GetLastError());
239 LOG_ERROR("Failed to create thread at entry point %p with data %p.", entryPoint, data);
241 LOG_ERROR("Failed to create thread at entry point %p with data %p: %ld", entryPoint, data, errno);
246 // The thread will take ownership of invocation.
247 ThreadFunctionInvocation* leakedInvocation = invocation.leakPtr();
248 UNUSED_PARAM(leakedInvocation);
250 threadID = static_cast<ThreadIdentifier>(threadIdentifier);
251 storeThreadHandleByIdentifier(threadIdentifier, threadHandle);
256 int waitForThreadCompletion(ThreadIdentifier threadID)
260 HANDLE threadHandle = threadHandleForIdentifier(threadID);
262 LOG_ERROR("ThreadIdentifier %u did not correspond to an active thread when trying to quit", threadID);
264 DWORD joinResult = WaitForSingleObject(threadHandle, INFINITE);
265 if (joinResult == WAIT_FAILED)
266 LOG_ERROR("ThreadIdentifier %u was found to be deadlocked trying to quit", threadID);
268 CloseHandle(threadHandle);
269 clearThreadHandleForIdentifier(threadID);
274 void detachThread(ThreadIdentifier threadID)
278 HANDLE threadHandle = threadHandleForIdentifier(threadID);
280 CloseHandle(threadHandle);
281 clearThreadHandleForIdentifier(threadID);
289 ThreadIdentifier currentThread()
291 return static_cast<ThreadIdentifier>(GetCurrentThreadId());
296 m_mutex.m_recursionCount = 0;
297 InitializeCriticalSection(&m_mutex.m_internalMutex);
302 DeleteCriticalSection(&m_mutex.m_internalMutex);
307 EnterCriticalSection(&m_mutex.m_internalMutex);
308 ++m_mutex.m_recursionCount;
311 bool Mutex::tryLock()
313 // This method is modeled after the behavior of pthread_mutex_trylock,
314 // which will return an error if the lock is already owned by the
315 // current thread. Since the primitive Win32 'TryEnterCriticalSection'
316 // treats this as a successful case, it changes the behavior of several
317 // tests in WebKit that check to see if the current thread already
318 // owned this mutex (see e.g., IconDatabase::getOrCreateIconRecord)
319 DWORD result = TryEnterCriticalSection(&m_mutex.m_internalMutex);
321 if (result != 0) { // We got the lock
322 // If this thread already had the lock, we must unlock and
323 // return false so that we mimic the behavior of POSIX's
324 // pthread_mutex_trylock:
325 if (m_mutex.m_recursionCount > 0) {
326 LeaveCriticalSection(&m_mutex.m_internalMutex);
330 ++m_mutex.m_recursionCount;
339 ASSERT(m_mutex.m_recursionCount);
340 --m_mutex.m_recursionCount;
341 LeaveCriticalSection(&m_mutex.m_internalMutex);
344 bool PlatformCondition::timedWait(PlatformMutex& mutex, DWORD durationMilliseconds)
346 // Enter the wait state.
347 DWORD res = WaitForSingleObject(m_blockLock, INFINITE);
348 ASSERT_UNUSED(res, res == WAIT_OBJECT_0);
350 res = ReleaseSemaphore(m_blockLock, 1, 0);
351 ASSERT_UNUSED(res, res);
353 --mutex.m_recursionCount;
354 LeaveCriticalSection(&mutex.m_internalMutex);
356 // Main wait - use timeout.
357 bool timedOut = (WaitForSingleObject(m_blockQueue, durationMilliseconds) == WAIT_TIMEOUT);
359 res = WaitForSingleObject(m_unblockLock, INFINITE);
360 ASSERT_UNUSED(res, res == WAIT_OBJECT_0);
362 int signalsLeft = m_waitersToUnblock;
364 if (m_waitersToUnblock)
365 --m_waitersToUnblock;
366 else if (++m_waitersGone == (INT_MAX / 2)) { // timeout/canceled or spurious semaphore
367 // timeout or spurious wakeup occured, normalize the m_waitersGone count
368 // this may occur if many calls to wait with a timeout are made and
369 // no call to notify_* is made
370 res = WaitForSingleObject(m_blockLock, INFINITE);
371 ASSERT_UNUSED(res, res == WAIT_OBJECT_0);
372 m_waitersBlocked -= m_waitersGone;
373 res = ReleaseSemaphore(m_blockLock, 1, 0);
374 ASSERT_UNUSED(res, res);
378 res = ReleaseMutex(m_unblockLock);
379 ASSERT_UNUSED(res, res);
381 if (signalsLeft == 1) {
382 res = ReleaseSemaphore(m_blockLock, 1, 0); // Open the gate.
383 ASSERT_UNUSED(res, res);
386 EnterCriticalSection (&mutex.m_internalMutex);
387 ++mutex.m_recursionCount;
392 void PlatformCondition::signal(bool unblockAll)
394 unsigned signalsToIssue = 0;
396 DWORD res = WaitForSingleObject(m_unblockLock, INFINITE);
397 ASSERT_UNUSED(res, res == WAIT_OBJECT_0);
399 if (m_waitersToUnblock) { // the gate is already closed
400 if (!m_waitersBlocked) { // no-op
401 res = ReleaseMutex(m_unblockLock);
402 ASSERT_UNUSED(res, res);
407 signalsToIssue = m_waitersBlocked;
408 m_waitersToUnblock += m_waitersBlocked;
409 m_waitersBlocked = 0;
412 ++m_waitersToUnblock;
415 } else if (m_waitersBlocked > m_waitersGone) {
416 res = WaitForSingleObject(m_blockLock, INFINITE); // Close the gate.
417 ASSERT_UNUSED(res, res == WAIT_OBJECT_0);
418 if (m_waitersGone != 0) {
419 m_waitersBlocked -= m_waitersGone;
423 signalsToIssue = m_waitersBlocked;
424 m_waitersToUnblock = m_waitersBlocked;
425 m_waitersBlocked = 0;
428 m_waitersToUnblock = 1;
432 res = ReleaseMutex(m_unblockLock);
433 ASSERT_UNUSED(res, res);
437 res = ReleaseMutex(m_unblockLock);
438 ASSERT_UNUSED(res, res);
440 if (signalsToIssue) {
441 res = ReleaseSemaphore(m_blockQueue, signalsToIssue, 0);
442 ASSERT_UNUSED(res, res);
446 static const long MaxSemaphoreCount = static_cast<long>(~0UL >> 1);
448 ThreadCondition::ThreadCondition()
450 m_condition.m_waitersGone = 0;
451 m_condition.m_waitersBlocked = 0;
452 m_condition.m_waitersToUnblock = 0;
453 m_condition.m_blockLock = CreateSemaphore(0, 1, 1, 0);
454 m_condition.m_blockQueue = CreateSemaphore(0, 0, MaxSemaphoreCount, 0);
455 m_condition.m_unblockLock = CreateMutex(0, 0, 0);
457 if (!m_condition.m_blockLock || !m_condition.m_blockQueue || !m_condition.m_unblockLock) {
458 if (m_condition.m_blockLock)
459 CloseHandle(m_condition.m_blockLock);
460 if (m_condition.m_blockQueue)
461 CloseHandle(m_condition.m_blockQueue);
462 if (m_condition.m_unblockLock)
463 CloseHandle(m_condition.m_unblockLock);
467 ThreadCondition::~ThreadCondition()
469 CloseHandle(m_condition.m_blockLock);
470 CloseHandle(m_condition.m_blockQueue);
471 CloseHandle(m_condition.m_unblockLock);
474 void ThreadCondition::wait(Mutex& mutex)
476 m_condition.timedWait(mutex.impl(), INFINITE);
479 bool ThreadCondition::timedWait(Mutex& mutex, double absoluteTime)
481 DWORD interval = absoluteTimeToWaitTimeoutInterval(absoluteTime);
484 // Consider the wait to have timed out, even if our condition has already been signaled, to
485 // match the pthreads implementation.
489 return m_condition.timedWait(mutex.impl(), interval);
492 void ThreadCondition::signal()
494 m_condition.signal(false); // Unblock only 1 thread.
497 void ThreadCondition::broadcast()
499 m_condition.signal(true); // Unblock all threads.
502 DWORD absoluteTimeToWaitTimeoutInterval(double absoluteTime)
504 double currentTime = WTF::currentTime();
506 // Time is in the past - return immediately.
507 if (absoluteTime < currentTime)
510 // Time is too far in the future (and would overflow unsigned long) - wait forever.
511 if (absoluteTime - currentTime > static_cast<double>(INT_MAX) / 1000.0)
514 return static_cast<DWORD>((absoluteTime - currentTime) * 1000.0);