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) && PLATFORM(WIN_OS)
91 #include "ThreadSpecific.h"
92 #endif
93 #if !PLATFORM(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
setThreadNameInternal(const char * szThreadName)121 void setThreadNameInternal(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
lockAtomicallyInitializedStaticMutex()137 void lockAtomicallyInitializedStaticMutex()
138 {
139 ASSERT(atomicallyInitializedStaticMutex);
140 atomicallyInitializedStaticMutex->lock();
141 }
142
unlockAtomicallyInitializedStaticMutex()143 void unlockAtomicallyInitializedStaticMutex()
144 {
145 atomicallyInitializedStaticMutex->unlock();
146 }
147
148 static ThreadIdentifier mainThreadIdentifier;
149
threadMapMutex()150 static Mutex& threadMapMutex()
151 {
152 static Mutex mutex;
153 return mutex;
154 }
155
initializeThreading()156 void initializeThreading()
157 {
158 if (!atomicallyInitializedStaticMutex) {
159 atomicallyInitializedStaticMutex = new Mutex;
160 threadMapMutex();
161 initializeRandomNumberGenerator();
162 initializeMainThread();
163 mainThreadIdentifier = currentThread();
164 setThreadNameInternal("Main Thread");
165 }
166 }
167
threadMap()168 static HashMap<DWORD, HANDLE>& threadMap()
169 {
170 static HashMap<DWORD, HANDLE> map;
171 return map;
172 }
173
storeThreadHandleByIdentifier(DWORD threadID,HANDLE threadHandle)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
threadHandleForIdentifier(ThreadIdentifier id)181 static HANDLE threadHandleForIdentifier(ThreadIdentifier id)
182 {
183 MutexLocker locker(threadMapMutex());
184 return threadMap().get(id);
185 }
186
clearThreadHandleForIdentifier(ThreadIdentifier id)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 {
ThreadFunctionInvocationWTF::ThreadFunctionInvocation195 ThreadFunctionInvocation(ThreadFunction function, void* data) : function(function), data(data) {}
196
197 ThreadFunction function;
198 void* data;
199 };
200
wtfThreadEntryPoint(void * param)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) && PLATFORM(WIN_OS)
209 // Do the TLS cleanup.
210 ThreadSpecificThreadExit();
211 #endif
212
213 return reinterpret_cast<unsigned>(result);
214 }
215
createThreadInternal(ThreadFunction entryPoint,void * data,const char * threadName)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 PLATFORM(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 PLATFORM(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
waitForThreadCompletion(ThreadIdentifier threadID,void ** result)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
detachThread(ThreadIdentifier threadID)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
currentThread()273 ThreadIdentifier currentThread()
274 {
275 return static_cast<ThreadIdentifier>(GetCurrentThreadId());
276 }
277
isMainThread()278 bool isMainThread()
279 {
280 return currentThread() == mainThreadIdentifier;
281 }
282
Mutex()283 Mutex::Mutex()
284 {
285 m_mutex.m_recursionCount = 0;
286 InitializeCriticalSection(&m_mutex.m_internalMutex);
287 }
288
~Mutex()289 Mutex::~Mutex()
290 {
291 DeleteCriticalSection(&m_mutex.m_internalMutex);
292 }
293
lock()294 void Mutex::lock()
295 {
296 EnterCriticalSection(&m_mutex.m_internalMutex);
297 ++m_mutex.m_recursionCount;
298 }
299
tryLock()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
unlock()326 void Mutex::unlock()
327 {
328 --m_mutex.m_recursionCount;
329 LeaveCriticalSection(&m_mutex.m_internalMutex);
330 }
331
timedWait(PlatformMutex & mutex,DWORD durationMilliseconds)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
signal(bool unblockAll)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
ThreadCondition()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
~ThreadCondition()453 ThreadCondition::~ThreadCondition()
454 {
455 CloseHandle(m_condition.m_blockLock);
456 CloseHandle(m_condition.m_blockQueue);
457 CloseHandle(m_condition.m_unblockLock);
458 }
459
wait(Mutex & mutex)460 void ThreadCondition::wait(Mutex& mutex)
461 {
462 m_condition.timedWait(mutex.impl(), INFINITE);
463 }
464
timedWait(Mutex & mutex,double absoluteTime)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
signal()483 void ThreadCondition::signal()
484 {
485 m_condition.signal(false); // Unblock only 1 thread.
486 }
487
broadcast()488 void ThreadCondition::broadcast()
489 {
490 m_condition.signal(true); // Unblock all threads.
491 }
492
493 } // namespace WTF
494