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 #if OS(WIN)
90
91 #include "wtf/CurrentTime.h"
92 #include "wtf/DateMath.h"
93 #include "wtf/HashMap.h"
94 #include "wtf/MainThread.h"
95 #include "wtf/MathExtras.h"
96 #include "wtf/OwnPtr.h"
97 #include "wtf/PassOwnPtr.h"
98 #include "wtf/ThreadFunctionInvocation.h"
99 #include "wtf/ThreadSpecific.h"
100 #include "wtf/ThreadingPrimitives.h"
101 #include "wtf/WTFThreadData.h"
102 #include "wtf/dtoa.h"
103 #include "wtf/dtoa/cached-powers.h"
104 #include <errno.h>
105 #include <process.h>
106 #include <windows.h>
107
108 namespace WTF {
109
110 // MS_VC_EXCEPTION, THREADNAME_INFO, and setThreadNameInternal all come from <http://msdn.microsoft.com/en-us/library/xcb2z8hs.aspx>.
111 static const DWORD MS_VC_EXCEPTION = 0x406D1388;
112
113 #pragma pack(push, 8)
114 typedef struct tagTHREADNAME_INFO {
115 DWORD dwType; // must be 0x1000
116 LPCSTR szName; // pointer to name (in user addr space)
117 DWORD dwThreadID; // thread ID (-1=caller thread)
118 DWORD dwFlags; // reserved for future use, must be zero
119 } THREADNAME_INFO;
120 #pragma pack(pop)
121
initializeCurrentThreadInternal(const char * szThreadName)122 void initializeCurrentThreadInternal(const char* szThreadName)
123 {
124 THREADNAME_INFO info;
125 info.dwType = 0x1000;
126 info.szName = szThreadName;
127 info.dwThreadID = GetCurrentThreadId();
128 info.dwFlags = 0;
129
130 __try {
131 RaiseException(MS_VC_EXCEPTION, 0, sizeof(info)/sizeof(ULONG_PTR), reinterpret_cast<ULONG_PTR*>(&info));
132 } __except (EXCEPTION_CONTINUE_EXECUTION) {
133 }
134 }
135
136 static Mutex* atomicallyInitializedStaticMutex;
137
lockAtomicallyInitializedStaticMutex()138 void lockAtomicallyInitializedStaticMutex()
139 {
140 ASSERT(atomicallyInitializedStaticMutex);
141 atomicallyInitializedStaticMutex->lock();
142 }
143
unlockAtomicallyInitializedStaticMutex()144 void unlockAtomicallyInitializedStaticMutex()
145 {
146 atomicallyInitializedStaticMutex->unlock();
147 }
148
threadMapMutex()149 static Mutex& threadMapMutex()
150 {
151 static Mutex mutex;
152 return mutex;
153 }
154
initializeThreading()155 void initializeThreading()
156 {
157 // This should only be called once.
158 ASSERT(!atomicallyInitializedStaticMutex);
159
160 // StringImpl::empty() does not construct its static string in a threadsafe fashion,
161 // so ensure it has been initialized from here.
162 StringImpl::empty();
163 atomicallyInitializedStaticMutex = new Mutex;
164 threadMapMutex();
165 wtfThreadData();
166 s_dtoaP5Mutex = new Mutex;
167 initializeDates();
168 }
169
threadMap()170 static HashMap<DWORD, HANDLE>& threadMap()
171 {
172 static HashMap<DWORD, HANDLE>* gMap;
173 if (!gMap)
174 gMap = new HashMap<DWORD, HANDLE>();
175 return *gMap;
176 }
177
storeThreadHandleByIdentifier(DWORD threadID,HANDLE threadHandle)178 static void storeThreadHandleByIdentifier(DWORD threadID, HANDLE threadHandle)
179 {
180 MutexLocker locker(threadMapMutex());
181 ASSERT(!threadMap().contains(threadID));
182 threadMap().add(threadID, threadHandle);
183 }
184
threadHandleForIdentifier(ThreadIdentifier id)185 static HANDLE threadHandleForIdentifier(ThreadIdentifier id)
186 {
187 MutexLocker locker(threadMapMutex());
188 return threadMap().get(id);
189 }
190
clearThreadHandleForIdentifier(ThreadIdentifier id)191 static void clearThreadHandleForIdentifier(ThreadIdentifier id)
192 {
193 MutexLocker locker(threadMapMutex());
194 ASSERT(threadMap().contains(id));
195 threadMap().remove(id);
196 }
197
wtfThreadEntryPoint(void * param)198 static unsigned __stdcall wtfThreadEntryPoint(void* param)
199 {
200 OwnPtr<ThreadFunctionInvocation> invocation = adoptPtr(static_cast<ThreadFunctionInvocation*>(param));
201 invocation->function(invocation->data);
202
203 // Do the TLS cleanup.
204 ThreadSpecificThreadExit();
205
206 return 0;
207 }
208
createThreadInternal(ThreadFunction entryPoint,void * data,const char * threadName)209 ThreadIdentifier createThreadInternal(ThreadFunction entryPoint, void* data, const char* threadName)
210 {
211 unsigned threadIdentifier = 0;
212 ThreadIdentifier threadID = 0;
213 OwnPtr<ThreadFunctionInvocation> invocation = adoptPtr(new ThreadFunctionInvocation(entryPoint, data));
214 HANDLE threadHandle = reinterpret_cast<HANDLE>(_beginthreadex(0, 0, wtfThreadEntryPoint, invocation.get(), 0, &threadIdentifier));
215 if (!threadHandle) {
216 WTF_LOG_ERROR("Failed to create thread at entry point %p with data %p: %ld", entryPoint, data, errno);
217 return 0;
218 }
219
220 // The thread will take ownership of invocation.
221 ThreadFunctionInvocation* ALLOW_UNUSED leakedInvocation = invocation.leakPtr();
222
223 threadID = static_cast<ThreadIdentifier>(threadIdentifier);
224 storeThreadHandleByIdentifier(threadIdentifier, threadHandle);
225
226 return threadID;
227 }
228
waitForThreadCompletion(ThreadIdentifier threadID)229 int waitForThreadCompletion(ThreadIdentifier threadID)
230 {
231 ASSERT(threadID);
232
233 HANDLE threadHandle = threadHandleForIdentifier(threadID);
234 if (!threadHandle)
235 WTF_LOG_ERROR("ThreadIdentifier %u did not correspond to an active thread when trying to quit", threadID);
236
237 DWORD joinResult = WaitForSingleObject(threadHandle, INFINITE);
238 if (joinResult == WAIT_FAILED)
239 WTF_LOG_ERROR("ThreadIdentifier %u was found to be deadlocked trying to quit", threadID);
240
241 CloseHandle(threadHandle);
242 clearThreadHandleForIdentifier(threadID);
243
244 return joinResult;
245 }
246
detachThread(ThreadIdentifier threadID)247 void detachThread(ThreadIdentifier threadID)
248 {
249 ASSERT(threadID);
250
251 HANDLE threadHandle = threadHandleForIdentifier(threadID);
252 if (threadHandle)
253 CloseHandle(threadHandle);
254 clearThreadHandleForIdentifier(threadID);
255 }
256
yield()257 void yield()
258 {
259 ::Sleep(1);
260 }
261
currentThread()262 ThreadIdentifier currentThread()
263 {
264 return static_cast<ThreadIdentifier>(GetCurrentThreadId());
265 }
266
Mutex()267 Mutex::Mutex()
268 {
269 m_mutex.m_recursionCount = 0;
270 InitializeCriticalSection(&m_mutex.m_internalMutex);
271 }
272
~Mutex()273 Mutex::~Mutex()
274 {
275 DeleteCriticalSection(&m_mutex.m_internalMutex);
276 }
277
lock()278 void Mutex::lock()
279 {
280 EnterCriticalSection(&m_mutex.m_internalMutex);
281 ++m_mutex.m_recursionCount;
282 }
283
tryLock()284 bool Mutex::tryLock()
285 {
286 // This method is modeled after the behavior of pthread_mutex_trylock,
287 // which will return an error if the lock is already owned by the
288 // current thread. Since the primitive Win32 'TryEnterCriticalSection'
289 // treats this as a successful case, it changes the behavior of several
290 // tests in WebKit that check to see if the current thread already
291 // owned this mutex (see e.g., IconDatabase::getOrCreateIconRecord)
292 DWORD result = TryEnterCriticalSection(&m_mutex.m_internalMutex);
293
294 if (result != 0) { // We got the lock
295 // If this thread already had the lock, we must unlock and
296 // return false so that we mimic the behavior of POSIX's
297 // pthread_mutex_trylock:
298 if (m_mutex.m_recursionCount > 0) {
299 LeaveCriticalSection(&m_mutex.m_internalMutex);
300 return false;
301 }
302
303 ++m_mutex.m_recursionCount;
304 return true;
305 }
306
307 return false;
308 }
309
unlock()310 void Mutex::unlock()
311 {
312 ASSERT(m_mutex.m_recursionCount);
313 --m_mutex.m_recursionCount;
314 LeaveCriticalSection(&m_mutex.m_internalMutex);
315 }
316
timedWait(PlatformMutex & mutex,DWORD durationMilliseconds)317 bool PlatformCondition::timedWait(PlatformMutex& mutex, DWORD durationMilliseconds)
318 {
319 // Enter the wait state.
320 DWORD res = WaitForSingleObject(m_blockLock, INFINITE);
321 ASSERT_UNUSED(res, res == WAIT_OBJECT_0);
322 ++m_waitersBlocked;
323 res = ReleaseSemaphore(m_blockLock, 1, 0);
324 ASSERT_UNUSED(res, res);
325
326 --mutex.m_recursionCount;
327 LeaveCriticalSection(&mutex.m_internalMutex);
328
329 // Main wait - use timeout.
330 bool timedOut = (WaitForSingleObject(m_blockQueue, durationMilliseconds) == WAIT_TIMEOUT);
331
332 res = WaitForSingleObject(m_unblockLock, INFINITE);
333 ASSERT_UNUSED(res, res == WAIT_OBJECT_0);
334
335 int signalsLeft = m_waitersToUnblock;
336
337 if (m_waitersToUnblock)
338 --m_waitersToUnblock;
339 else if (++m_waitersGone == (INT_MAX / 2)) { // timeout/canceled or spurious semaphore
340 // timeout or spurious wakeup occured, normalize the m_waitersGone count
341 // this may occur if many calls to wait with a timeout are made and
342 // no call to notify_* is made
343 res = WaitForSingleObject(m_blockLock, INFINITE);
344 ASSERT_UNUSED(res, res == WAIT_OBJECT_0);
345 m_waitersBlocked -= m_waitersGone;
346 res = ReleaseSemaphore(m_blockLock, 1, 0);
347 ASSERT_UNUSED(res, res);
348 m_waitersGone = 0;
349 }
350
351 res = ReleaseMutex(m_unblockLock);
352 ASSERT_UNUSED(res, res);
353
354 if (signalsLeft == 1) {
355 res = ReleaseSemaphore(m_blockLock, 1, 0); // Open the gate.
356 ASSERT_UNUSED(res, res);
357 }
358
359 EnterCriticalSection (&mutex.m_internalMutex);
360 ++mutex.m_recursionCount;
361
362 return !timedOut;
363 }
364
signal(bool unblockAll)365 void PlatformCondition::signal(bool unblockAll)
366 {
367 unsigned signalsToIssue = 0;
368
369 DWORD res = WaitForSingleObject(m_unblockLock, INFINITE);
370 ASSERT_UNUSED(res, 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_UNUSED(res, 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_UNUSED(res, 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_UNUSED(res, res);
407 return;
408 }
409
410 res = ReleaseMutex(m_unblockLock);
411 ASSERT_UNUSED(res, res);
412
413 if (signalsToIssue) {
414 res = ReleaseSemaphore(m_blockQueue, signalsToIssue, 0);
415 ASSERT_UNUSED(res, res);
416 }
417 }
418
419 static const long MaxSemaphoreCount = static_cast<long>(~0UL >> 1);
420
ThreadCondition()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
~ThreadCondition()440 ThreadCondition::~ThreadCondition()
441 {
442 CloseHandle(m_condition.m_blockLock);
443 CloseHandle(m_condition.m_blockQueue);
444 CloseHandle(m_condition.m_unblockLock);
445 }
446
wait(Mutex & mutex)447 void ThreadCondition::wait(Mutex& mutex)
448 {
449 m_condition.timedWait(mutex.impl(), INFINITE);
450 }
451
timedWait(Mutex & mutex,double absoluteTime)452 bool ThreadCondition::timedWait(Mutex& mutex, double absoluteTime)
453 {
454 DWORD interval = absoluteTimeToWaitTimeoutInterval(absoluteTime);
455
456 if (!interval) {
457 // Consider the wait to have timed out, even if our condition has already been signaled, to
458 // match the pthreads implementation.
459 return false;
460 }
461
462 return m_condition.timedWait(mutex.impl(), interval);
463 }
464
signal()465 void ThreadCondition::signal()
466 {
467 m_condition.signal(false); // Unblock only 1 thread.
468 }
469
broadcast()470 void ThreadCondition::broadcast()
471 {
472 m_condition.signal(true); // Unblock all threads.
473 }
474
absoluteTimeToWaitTimeoutInterval(double absoluteTime)475 DWORD absoluteTimeToWaitTimeoutInterval(double absoluteTime)
476 {
477 double currentTime = WTF::currentTime();
478
479 // Time is in the past - return immediately.
480 if (absoluteTime < currentTime)
481 return 0;
482
483 // Time is too far in the future (and would overflow unsigned long) - wait forever.
484 if (absoluteTime - currentTime > static_cast<double>(INT_MAX) / 1000.0)
485 return INFINITE;
486
487 return static_cast<DWORD>((absoluteTime - currentTime) * 1000.0);
488 }
489
490 } // namespace WTF
491
492 #endif // OS(WIN)
493