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/*
* Copyright (C) 2007, 2008, 2015 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 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 <wtf/Threading.h>
#include <errno.h>
#include <process.h>
#include <windows.h>
#include <wtf/HashMap.h>
#include <wtf/Lock.h>
#include <wtf/MainThread.h>
#include <wtf/MathExtras.h>
#include <wtf/NeverDestroyed.h>
#include <wtf/ThreadingPrimitives.h>
namespace WTF {
static Lock globalSuspendLock;
Thread::~Thread()
{
// It is OK because FLSAlloc's callback will be called even before there are some open handles.
// This easily ensures that all the thread resources are automatically closed.
if (m_handle != INVALID_HANDLE_VALUE)
CloseHandle(m_handle);
}
void Thread::initializeCurrentThreadEvenIfNonWTFCreated()
{
}
// 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 Thread::initializeCurrentThreadInternal(const char* szThreadName)
{
#if COMPILER(MINGW)
// FIXME: Implement thread name setting with MingW.
UNUSED_PARAM(szThreadName);
#else
THREADNAME_INFO info;
info.dwType = 0x1000;
info.szName = Thread::normalizeThreadName(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) { }
#endif
initializeCurrentThreadEvenIfNonWTFCreated();
}
void Thread::initializePlatformThreading()
{
}
static unsigned __stdcall wtfThreadEntryPoint(void* data)
{
Thread::entryPoint(reinterpret_cast<Thread::NewThreadContext*>(data));
return 0;
}
bool Thread::establishHandle(NewThreadContext* data, Optional<size_t> stackSize)
{
unsigned threadIdentifier = 0;
unsigned initFlag = stackSize ? STACK_SIZE_PARAM_IS_A_RESERVATION : 0;
HANDLE threadHandle = reinterpret_cast<HANDLE>(_beginthreadex(0, stackSize.valueOr(0), wtfThreadEntryPoint, data, initFlag, &threadIdentifier));
if (!threadHandle) {
LOG_ERROR("Failed to create thread at entry point %p with data %p: %ld", wtfThreadEntryPoint, data, errno);
return false;
}
establishPlatformSpecificHandle(threadHandle, threadIdentifier);
return true;
}
void Thread::changePriority(int delta)
{
auto locker = holdLock(m_mutex);
SetThreadPriority(m_handle, THREAD_PRIORITY_NORMAL + delta);
}
int Thread::waitForCompletion()
{
HANDLE handle;
{
auto locker = holdLock(m_mutex);
handle = m_handle;
}
DWORD joinResult = WaitForSingleObject(handle, INFINITE);
if (joinResult == WAIT_FAILED)
LOG_ERROR("Thread %p was found to be deadlocked trying to quit", this);
auto locker = holdLock(m_mutex);
ASSERT(joinableState() == Joinable);
// The thread has already exited, do nothing.
// The thread hasn't exited yet, so don't clean anything up. Just signal that we've already joined on it so that it will clean up after itself.
if (!hasExited())
didJoin();
return joinResult;
}
void Thread::detach()
{
// We follow the pthread semantics: even after the detach is called,
// we can still perform various operations onto the thread. For example,
// we can do pthread_kill for the detached thread. The problem in Windows
// is that closing HANDLE loses the way to do such operations.
// To do so, we do nothing here in Windows. Original detach's purpose,
// releasing thread resource when the thread exits, will be achieved by
// FlsCallback automatically. FlsCallback will call CloseHandle to clean up
// resource. So in this function, we just mark the thread as detached to
// avoid calling waitForCompletion for this thread.
auto locker = holdLock(m_mutex);
if (!hasExited())
didBecomeDetached();
}
auto Thread::suspend() -> Expected<void, PlatformSuspendError>
{
RELEASE_ASSERT_WITH_MESSAGE(this != &Thread::current(), "We do not support suspending the current thread itself.");
LockHolder locker(globalSuspendLock);
DWORD result = SuspendThread(m_handle);
if (result != (DWORD)-1)
return { };
return makeUnexpected(result);
}
// During resume, suspend or resume should not be executed from the other threads.
void Thread::resume()
{
LockHolder locker(globalSuspendLock);
ResumeThread(m_handle);
}
size_t Thread::getRegisters(PlatformRegisters& registers)
{
LockHolder locker(globalSuspendLock);
registers.ContextFlags = CONTEXT_INTEGER | CONTEXT_CONTROL;
GetThreadContext(m_handle, &registers);
return sizeof(CONTEXT);
}
Thread& Thread::initializeCurrentTLS()
{
// Not a WTF-created thread, ThreadIdentifier is not established yet.
Ref<Thread> thread = adoptRef(*new Thread());
HANDLE handle;
bool isSuccessful = DuplicateHandle(GetCurrentProcess(), GetCurrentThread(), GetCurrentProcess(), &handle, 0, FALSE, DUPLICATE_SAME_ACCESS);
RELEASE_ASSERT(isSuccessful);
thread->establishPlatformSpecificHandle(handle, currentID());
thread->initializeInThread();
initializeCurrentThreadEvenIfNonWTFCreated();
return initializeTLS(WTFMove(thread));
}
ThreadIdentifier Thread::currentID()
{
return static_cast<ThreadIdentifier>(GetCurrentThreadId());
}
void Thread::establishPlatformSpecificHandle(HANDLE handle, ThreadIdentifier threadID)
{
auto locker = holdLock(m_mutex);
m_handle = handle;
m_id = threadID;
}
struct Thread::ThreadHolder {
~ThreadHolder()
{
if (thread) {
thread->specificStorage().destroySlots();
thread->didExit();
}
}
RefPtr<Thread> thread;
};
thread_local static Thread::ThreadHolder s_threadHolder;
Thread* Thread::currentMayBeNull()
{
return s_threadHolder.thread.get();
}
Thread& Thread::initializeTLS(Ref<Thread>&& thread)
{
s_threadHolder.thread = WTFMove(thread);
return *s_threadHolder.thread;
}
Atomic<int> Thread::SpecificStorage::s_numberOfKeys;
std::array<Atomic<Thread::SpecificStorage::DestroyFunction>, Thread::SpecificStorage::s_maxKeys> Thread::SpecificStorage::s_destroyFunctions;
bool Thread::SpecificStorage::allocateKey(int& key, DestroyFunction destroy)
{
int k = s_numberOfKeys.exchangeAdd(1);
if (k >= s_maxKeys) {
s_numberOfKeys.exchangeSub(1);
return false;
}
key = k;
s_destroyFunctions[key].store(destroy);
return true;
}
void* Thread::SpecificStorage::get(int key)
{
return m_slots[key];
}
void Thread::SpecificStorage::set(int key, void* value)
{
m_slots[key] = value;
}
void Thread::SpecificStorage::destroySlots()
{
auto numberOfKeys = s_numberOfKeys.load();
for (size_t i = 0; i < numberOfKeys; i++) {
auto destroy = s_destroyFunctions[i].load();
if (destroy && m_slots[i]) {
destroy(m_slots[i]);
m_slots[i] = nullptr;
}
}
}
Mutex::~Mutex()
{
}
void Mutex::lock()
{
AcquireSRWLockExclusive(&m_mutex);
}
bool Mutex::tryLock()
{
return TryAcquireSRWLockExclusive(&m_mutex);
}
void Mutex::unlock()
{
ReleaseSRWLockExclusive(&m_mutex);
}
// Returns an interval in milliseconds suitable for passing to one of the Win32 wait functions (e.g., ::WaitForSingleObject).
static DWORD absoluteTimeToWaitTimeoutInterval(WallTime absoluteTime)
{
WallTime currentTime = WallTime::now();
// Time is in the past - return immediately.
if (absoluteTime < currentTime)
return 0;
// Time is too far in the future (and would overflow unsigned long) - wait forever.
if ((absoluteTime - currentTime) > Seconds::fromMilliseconds(INT_MAX))
return INFINITE;
return static_cast<DWORD>((absoluteTime - currentTime).milliseconds());
}
ThreadCondition::~ThreadCondition()
{
}
void ThreadCondition::wait(Mutex& mutex)
{
SleepConditionVariableSRW(&m_condition, &mutex.impl(), INFINITE, 0);
}
bool ThreadCondition::timedWait(Mutex& mutex, WallTime absoluteTime)
{
// https://msdn.microsoft.com/en-us/library/windows/desktop/ms686304(v=vs.85).aspx
DWORD interval = absoluteTimeToWaitTimeoutInterval(absoluteTime);
if (!interval) {
// Consider the wait to have timed out, even if our condition has already been signaled, to
// match the pthreads implementation.
return false;
}
if (SleepConditionVariableSRW(&m_condition, &mutex.impl(), interval, 0))
return true;
ASSERT(GetLastError() == ERROR_TIMEOUT);
return false;
}
void ThreadCondition::signal()
{
WakeConditionVariable(&m_condition);
}
void ThreadCondition::broadcast()
{
WakeAllConditionVariable(&m_condition);
}
void Thread::yield()
{
SwitchToThread();
}
} // namespace WTF