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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mozilla/DebugOnly.h"
#include "jswin.h"
#include "js/Utility.h"
#include "threading/Mutex.h"
#include "threading/windows/MutexPlatformData.h"
namespace {
// We build with a toolkit that supports WinXP, so we have to probe
// for modern features at runtime. This is necessary because Vista and
// later automatically allocate and subsequently leak a debug info
// object for each critical section that we allocate unless we tell it
// not to. In order to tell it not to, we need the extra flags field
// provided by the Ex version of InitializeCriticalSection.
struct MutexNativeImports
{
using InitializeCriticalSectionExT = BOOL (WINAPI*)(CRITICAL_SECTION*, DWORD, DWORD);
InitializeCriticalSectionExT InitializeCriticalSectionEx;
MutexNativeImports() {
HMODULE kernel32_dll = GetModuleHandle("kernel32.dll");
MOZ_RELEASE_ASSERT(kernel32_dll != NULL);
InitializeCriticalSectionEx = reinterpret_cast<InitializeCriticalSectionExT>(
GetProcAddress(kernel32_dll, "InitializeCriticalSectionEx"));
}
bool hasInitializeCriticalSectionEx() const {
return InitializeCriticalSectionEx;
}
};
static MutexNativeImports NativeImports;
} // (anonymous namespace)
js::detail::MutexImpl::MutexImpl()
{
AutoEnterOOMUnsafeRegion oom;
platformData_ = js_new<PlatformData>();
if (!platformData_)
oom.crash("js::Mutex::Mutex");
// This number was adopted from NSPR.
const static DWORD LockSpinCount = 1500;
BOOL r;
if (NativeImports.hasInitializeCriticalSectionEx()) {
r = NativeImports.InitializeCriticalSectionEx(&platformData()->criticalSection,
LockSpinCount,
CRITICAL_SECTION_NO_DEBUG_INFO);
} else {
r = InitializeCriticalSectionAndSpinCount(&platformData()->criticalSection,
LockSpinCount);
}
MOZ_RELEASE_ASSERT(r);
}
js::detail::MutexImpl::~MutexImpl()
{
if (!platformData_)
return;
DeleteCriticalSection(&platformData()->criticalSection);
js_delete(platformData());
}
void
js::detail::MutexImpl::lock()
{
EnterCriticalSection(&platformData()->criticalSection);
}
void
js::detail::MutexImpl::unlock()
{
LeaveCriticalSection(&platformData()->criticalSection);
}
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