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
111namespace WTF {
112
113// MS_VC_EXCEPTION, THREADNAME_INFO, and setThreadNameInternal all come from <http://msdn.microsoft.com/en-us/library/xcb2z8hs.aspx>.
114static const DWORD MS_VC_EXCEPTION = 0x406D1388;
115
116#pragma pack(push, 8)
117typedef 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
125void 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
139static Mutex* atomicallyInitializedStaticMutex;
140
141void lockAtomicallyInitializedStaticMutex()
142{
143    ASSERT(atomicallyInitializedStaticMutex);
144    atomicallyInitializedStaticMutex->lock();
145}
146
147void unlockAtomicallyInitializedStaticMutex()
148{
149    atomicallyInitializedStaticMutex->unlock();
150}
151
152static Mutex& threadMapMutex()
153{
154    static Mutex mutex;
155    return mutex;
156}
157
158void initializeThreading()
159{
160    if (atomicallyInitializedStaticMutex)
161        return;
162
163    atomicallyInitializedStaticMutex = new Mutex;
164    threadMapMutex();
165    initializeRandomNumberGenerator();
166}
167
168static HashMap<DWORD, HANDLE>& threadMap()
169{
170    static HashMap<DWORD, HANDLE> map;
171    return map;
172}
173
174static void storeThreadHandleByIdentifier(DWORD threadID, HANDLE threadHandle)
175{
176    MutexLocker locker(threadMapMutex());
177    ASSERT(!threadMap().contains(threadID));
178    threadMap().add(threadID, threadHandle);
179}
180
181static HANDLE threadHandleForIdentifier(ThreadIdentifier id)
182{
183    MutexLocker locker(threadMapMutex());
184    return threadMap().get(id);
185}
186
187static void clearThreadHandleForIdentifier(ThreadIdentifier id)
188{
189    MutexLocker locker(threadMapMutex());
190    ASSERT(threadMap().contains(id));
191    threadMap().remove(id);
192}
193
194static 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
207ThreadIdentifier 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
239int 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
257void detachThread(ThreadIdentifier threadID)
258{
259    ASSERT(threadID);
260
261    HANDLE threadHandle = threadHandleForIdentifier(threadID);
262    if (threadHandle)
263        CloseHandle(threadHandle);
264    clearThreadHandleForIdentifier(threadID);
265}
266
267void yield()
268{
269    ::Sleep(1);
270}
271
272ThreadIdentifier currentThread()
273{
274    return static_cast<ThreadIdentifier>(GetCurrentThreadId());
275}
276
277Mutex::Mutex()
278{
279    m_mutex.m_recursionCount = 0;
280    InitializeCriticalSection(&m_mutex.m_internalMutex);
281}
282
283Mutex::~Mutex()
284{
285    DeleteCriticalSection(&m_mutex.m_internalMutex);
286}
287
288void Mutex::lock()
289{
290    EnterCriticalSection(&m_mutex.m_internalMutex);
291    ++m_mutex.m_recursionCount;
292}
293
294bool 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
320void Mutex::unlock()
321{
322    --m_mutex.m_recursionCount;
323    LeaveCriticalSection(&m_mutex.m_internalMutex);
324}
325
326bool 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
374void 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
428static const long MaxSemaphoreCount = static_cast<long>(~0UL >> 1);
429
430ThreadCondition::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
449ThreadCondition::~ThreadCondition()
450{
451    CloseHandle(m_condition.m_blockLock);
452    CloseHandle(m_condition.m_blockQueue);
453    CloseHandle(m_condition.m_unblockLock);
454}
455
456void ThreadCondition::wait(Mutex& mutex)
457{
458    m_condition.timedWait(mutex.impl(), INFINITE);
459}
460
461bool 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
474void ThreadCondition::signal()
475{
476    m_condition.signal(false); // Unblock only 1 thread.
477}
478
479void ThreadCondition::broadcast()
480{
481    m_condition.signal(true); // Unblock all threads.
482}
483
484DWORD 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
500