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/*
* Copyright (C) 2007, 2008 Apple Inc. All rights reserved.
* Copyright (C) 2009 Google Inc. All rights reserved.
* Copyright (C) 2009 Torch Mobile, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* There are numerous academic and practical works on how to implement pthread_cond_wait/pthread_cond_signal/pthread_cond_broadcast
* 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'
* of modern attempts. There are several more or less proven implementations, one in Boost C++ library (http://www.boost.org) and another
* in pthreads-win32 (http://sourceware.org/pthreads-win32/).
*
* The number of articles and discussions is the evidence of significant difficulties in implementing these primitives correctly.
* The brief search of revisions, ChangeLog entries, discussions in comp.programming.threads and other places clearly documents
* numerous pitfalls and performance problems the authors had to overcome to arrive to the suitable implementations.
* Optimally, WebKit would use one of those supported/tested libraries directly. To roll out our own implementation is impractical,
* if even for the lack of sufficient testing. However, a faithful reproduction of the code from one of the popular supported
* libraries seems to be a good compromise.
*
* 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)
* 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).
* Current Boost uses yet another (although seemingly equivalent) algorithm which came from their 'thread rewrite' effort.
*
* This file includes timedWait/signal/broadcast implementations translated to WebKit coding style from the latest algorithm by
* 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
* It replaces the implementation of their previous algorithm, also documented in the same source above.
* The naming and comments are left very close to original to enable easy cross-check.
*
* The corresponding Pthreads-win32 License is included below, and CONTRIBUTORS file which it refers to is added to
* source directory (as CONTRIBUTORS.pthreads-win32).
*/
/*
* Pthreads-win32 - POSIX Threads Library for Win32
* Copyright(C) 1998 John E. Bossom
* Copyright(C) 1999,2005 Pthreads-win32 contributors
*
* Contact Email: rpj@callisto.canberra.edu.au
*
* The current list of contributors is contained
* in the file CONTRIBUTORS included with the source
* code distribution. The list can also be seen at the
* following World Wide Web location:
* http://sources.redhat.com/pthreads-win32/contributors.html
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library in the file COPYING.LIB;
* if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#include "config.h"
#include "Threading.h"
#include "MainThread.h"
#if !USE(PTHREADS) && PLATFORM(WIN_OS)
#include "ThreadSpecific.h"
#endif
#if !PLATFORM(WINCE)
#include <process.h>
#endif
#if HAVE(ERRNO_H)
#include <errno.h>
#else
#define NO_ERRNO
#endif
#include <windows.h>
#include <wtf/CurrentTime.h>
#include <wtf/HashMap.h>
#include <wtf/MathExtras.h>
#include <wtf/RandomNumberSeed.h>
namespace WTF {
// MS_VC_EXCEPTION, THREADNAME_INFO, and setThreadNameInternal all come from <http://msdn.microsoft.com/en-us/library/xcb2z8hs.aspx>.
static const DWORD MS_VC_EXCEPTION = 0x406D1388;
#pragma pack(push, 8)
typedef struct tagTHREADNAME_INFO {
DWORD dwType; // must be 0x1000
LPCSTR szName; // pointer to name (in user addr space)
DWORD dwThreadID; // thread ID (-1=caller thread)
DWORD dwFlags; // reserved for future use, must be zero
} THREADNAME_INFO;
#pragma pack(pop)
void setThreadNameInternal(const char* szThreadName)
{
THREADNAME_INFO info;
info.dwType = 0x1000;
info.szName = szThreadName;
info.dwThreadID = GetCurrentThreadId();
info.dwFlags = 0;
__try {
RaiseException(MS_VC_EXCEPTION, 0, sizeof(info)/sizeof(ULONG_PTR), reinterpret_cast<ULONG_PTR*>(&info));
} __except (EXCEPTION_CONTINUE_EXECUTION) {
}
}
static Mutex* atomicallyInitializedStaticMutex;
void lockAtomicallyInitializedStaticMutex()
{
ASSERT(atomicallyInitializedStaticMutex);
atomicallyInitializedStaticMutex->lock();
}
void unlockAtomicallyInitializedStaticMutex()
{
atomicallyInitializedStaticMutex->unlock();
}
static ThreadIdentifier mainThreadIdentifier;
static Mutex& threadMapMutex()
{
static Mutex mutex;
return mutex;
}
void initializeThreading()
{
if (!atomicallyInitializedStaticMutex) {
atomicallyInitializedStaticMutex = new Mutex;
threadMapMutex();
initializeRandomNumberGenerator();
initializeMainThread();
mainThreadIdentifier = currentThread();
setThreadNameInternal("Main Thread");
}
}
static HashMap<DWORD, HANDLE>& threadMap()
{
static HashMap<DWORD, HANDLE> map;
return map;
}
static void storeThreadHandleByIdentifier(DWORD threadID, HANDLE threadHandle)
{
MutexLocker locker(threadMapMutex());
ASSERT(!threadMap().contains(threadID));
threadMap().add(threadID, threadHandle);
}
static HANDLE threadHandleForIdentifier(ThreadIdentifier id)
{
MutexLocker locker(threadMapMutex());
return threadMap().get(id);
}
static void clearThreadHandleForIdentifier(ThreadIdentifier id)
{
MutexLocker locker(threadMapMutex());
ASSERT(threadMap().contains(id));
threadMap().remove(id);
}
struct ThreadFunctionInvocation {
ThreadFunctionInvocation(ThreadFunction function, void* data) : function(function), data(data) {}
ThreadFunction function;
void* data;
};
static unsigned __stdcall wtfThreadEntryPoint(void* param)
{
ThreadFunctionInvocation invocation = *static_cast<ThreadFunctionInvocation*>(param);
delete static_cast<ThreadFunctionInvocation*>(param);
void* result = invocation.function(invocation.data);
#if !USE(PTHREADS) && PLATFORM(WIN_OS)
// Do the TLS cleanup.
ThreadSpecificThreadExit();
#endif
return reinterpret_cast<unsigned>(result);
}
ThreadIdentifier createThreadInternal(ThreadFunction entryPoint, void* data, const char* threadName)
{
unsigned threadIdentifier = 0;
ThreadIdentifier threadID = 0;
ThreadFunctionInvocation* invocation = new ThreadFunctionInvocation(entryPoint, data);
#if PLATFORM(WINCE)
// This is safe on WINCE, since CRT is in the core and innately multithreaded.
// On desktop Windows, need to use _beginthreadex (not available on WinCE) if using any CRT functions
HANDLE threadHandle = CreateThread(0, 0, (LPTHREAD_START_ROUTINE)wtfThreadEntryPoint, invocation, 0, (LPDWORD)&threadIdentifier);
#else
HANDLE threadHandle = reinterpret_cast<HANDLE>(_beginthreadex(0, 0, wtfThreadEntryPoint, invocation, 0, &threadIdentifier));
#endif
if (!threadHandle) {
#if PLATFORM(WINCE)
LOG_ERROR("Failed to create thread at entry point %p with data %p: %ld", entryPoint, data, ::GetLastError());
#elif defined(NO_ERRNO)
LOG_ERROR("Failed to create thread at entry point %p with data %p.", entryPoint, data);
#else
LOG_ERROR("Failed to create thread at entry point %p with data %p: %ld", entryPoint, data, errno);
#endif
return 0;
}
threadID = static_cast<ThreadIdentifier>(threadIdentifier);
storeThreadHandleByIdentifier(threadIdentifier, threadHandle);
return threadID;
}
int waitForThreadCompletion(ThreadIdentifier threadID, void** result)
{
ASSERT(threadID);
HANDLE threadHandle = threadHandleForIdentifier(threadID);
if (!threadHandle)
LOG_ERROR("ThreadIdentifier %u did not correspond to an active thread when trying to quit", threadID);
DWORD joinResult = WaitForSingleObject(threadHandle, INFINITE);
if (joinResult == WAIT_FAILED)
LOG_ERROR("ThreadIdentifier %u was found to be deadlocked trying to quit", threadID);
CloseHandle(threadHandle);
clearThreadHandleForIdentifier(threadID);
return joinResult;
}
void detachThread(ThreadIdentifier threadID)
{
ASSERT(threadID);
HANDLE threadHandle = threadHandleForIdentifier(threadID);
if (threadHandle)
CloseHandle(threadHandle);
clearThreadHandleForIdentifier(threadID);
}
ThreadIdentifier currentThread()
{
return static_cast<ThreadIdentifier>(GetCurrentThreadId());
}
bool isMainThread()
{
return currentThread() == mainThreadIdentifier;
}
Mutex::Mutex()
{
m_mutex.m_recursionCount = 0;
InitializeCriticalSection(&m_mutex.m_internalMutex);
}
Mutex::~Mutex()
{
DeleteCriticalSection(&m_mutex.m_internalMutex);
}
void Mutex::lock()
{
EnterCriticalSection(&m_mutex.m_internalMutex);
++m_mutex.m_recursionCount;
}
bool Mutex::tryLock()
{
// This method is modeled after the behavior of pthread_mutex_trylock,
// which will return an error if the lock is already owned by the
// current thread. Since the primitive Win32 'TryEnterCriticalSection'
// treats this as a successful case, it changes the behavior of several
// tests in WebKit that check to see if the current thread already
// owned this mutex (see e.g., IconDatabase::getOrCreateIconRecord)
DWORD result = TryEnterCriticalSection(&m_mutex.m_internalMutex);
if (result != 0) { // We got the lock
// If this thread already had the lock, we must unlock and
// return false so that we mimic the behavior of POSIX's
// pthread_mutex_trylock:
if (m_mutex.m_recursionCount > 0) {
LeaveCriticalSection(&m_mutex.m_internalMutex);
return false;
}
++m_mutex.m_recursionCount;
return true;
}
return false;
}
void Mutex::unlock()
{
--m_mutex.m_recursionCount;
LeaveCriticalSection(&m_mutex.m_internalMutex);
}
bool PlatformCondition::timedWait(PlatformMutex& mutex, DWORD durationMilliseconds)
{
// Enter the wait state.
DWORD res = WaitForSingleObject(m_blockLock, INFINITE);
ASSERT(res == WAIT_OBJECT_0);
++m_waitersBlocked;
res = ReleaseSemaphore(m_blockLock, 1, 0);
ASSERT(res);
LeaveCriticalSection(&mutex.m_internalMutex);
// Main wait - use timeout.
bool timedOut = (WaitForSingleObject(m_blockQueue, durationMilliseconds) == WAIT_TIMEOUT);
res = WaitForSingleObject(m_unblockLock, INFINITE);
ASSERT(res == WAIT_OBJECT_0);
int signalsLeft = m_waitersToUnblock;
if (m_waitersToUnblock)
--m_waitersToUnblock;
else if (++m_waitersGone == (INT_MAX / 2)) { // timeout/canceled or spurious semaphore
// timeout or spurious wakeup occured, normalize the m_waitersGone count
// this may occur if many calls to wait with a timeout are made and
// no call to notify_* is made
res = WaitForSingleObject(m_blockLock, INFINITE);
ASSERT(res == WAIT_OBJECT_0);
m_waitersBlocked -= m_waitersGone;
res = ReleaseSemaphore(m_blockLock, 1, 0);
ASSERT(res);
m_waitersGone = 0;
}
res = ReleaseMutex(m_unblockLock);
ASSERT(res);
if (signalsLeft == 1) {
res = ReleaseSemaphore(m_blockLock, 1, 0); // Open the gate.
ASSERT(res);
}
EnterCriticalSection (&mutex.m_internalMutex);
return !timedOut;
}
void PlatformCondition::signal(bool unblockAll)
{
unsigned signalsToIssue = 0;
DWORD res = WaitForSingleObject(m_unblockLock, INFINITE);
ASSERT(res == WAIT_OBJECT_0);
if (m_waitersToUnblock) { // the gate is already closed
if (!m_waitersBlocked) { // no-op
res = ReleaseMutex(m_unblockLock);
ASSERT(res);
return;
}
if (unblockAll) {
signalsToIssue = m_waitersBlocked;
m_waitersToUnblock += m_waitersBlocked;
m_waitersBlocked = 0;
} else {
signalsToIssue = 1;
++m_waitersToUnblock;
--m_waitersBlocked;
}
} else if (m_waitersBlocked > m_waitersGone) {
res = WaitForSingleObject(m_blockLock, INFINITE); // Close the gate.
ASSERT(res == WAIT_OBJECT_0);
if (m_waitersGone != 0) {
m_waitersBlocked -= m_waitersGone;
m_waitersGone = 0;
}
if (unblockAll) {
signalsToIssue = m_waitersBlocked;
m_waitersToUnblock = m_waitersBlocked;
m_waitersBlocked = 0;
} else {
signalsToIssue = 1;
m_waitersToUnblock = 1;
--m_waitersBlocked;
}
} else { // No-op.
res = ReleaseMutex(m_unblockLock);
ASSERT(res);
return;
}
res = ReleaseMutex(m_unblockLock);
ASSERT(res);
if (signalsToIssue) {
res = ReleaseSemaphore(m_blockQueue, signalsToIssue, 0);
ASSERT(res);
}
}
static const long MaxSemaphoreCount = static_cast<long>(~0UL >> 1);
ThreadCondition::ThreadCondition()
{
m_condition.m_waitersGone = 0;
m_condition.m_waitersBlocked = 0;
m_condition.m_waitersToUnblock = 0;
m_condition.m_blockLock = CreateSemaphore(0, 1, 1, 0);
m_condition.m_blockQueue = CreateSemaphore(0, 0, MaxSemaphoreCount, 0);
m_condition.m_unblockLock = CreateMutex(0, 0, 0);
if (!m_condition.m_blockLock || !m_condition.m_blockQueue || !m_condition.m_unblockLock) {
if (m_condition.m_blockLock)
CloseHandle(m_condition.m_blockLock);
if (m_condition.m_blockQueue)
CloseHandle(m_condition.m_blockQueue);
if (m_condition.m_unblockLock)
CloseHandle(m_condition.m_unblockLock);
}
}
ThreadCondition::~ThreadCondition()
{
CloseHandle(m_condition.m_blockLock);
CloseHandle(m_condition.m_blockQueue);
CloseHandle(m_condition.m_unblockLock);
}
void ThreadCondition::wait(Mutex& mutex)
{
m_condition.timedWait(mutex.impl(), INFINITE);
}
bool ThreadCondition::timedWait(Mutex& mutex, double absoluteTime)
{
double currentTime = WTF::currentTime();
// Time is in the past - return immediately.
if (absoluteTime < currentTime)
return false;
// Time is too far in the future (and would overflow unsigned long) - wait forever.
if (absoluteTime - currentTime > static_cast<double>(INT_MAX) / 1000.0) {
wait(mutex);
return true;
}
double intervalMilliseconds = (absoluteTime - currentTime) * 1000.0;
return m_condition.timedWait(mutex.impl(), static_cast<unsigned long>(intervalMilliseconds));
}
void ThreadCondition::signal()
{
m_condition.signal(false); // Unblock only 1 thread.
}
void ThreadCondition::broadcast()
{
m_condition.signal(true); // Unblock all threads.
}
} // namespace WTF
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