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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 */
#include <windows.h>
#include "base/process_util.h"
#include "CrossProcessMutex.h"
#include "nsDebug.h"
#include "nsISupportsImpl.h"
#include "ProtocolUtils.h"
using base::GetCurrentProcessHandle;
using base::ProcessHandle;
namespace mozilla {
CrossProcessMutex::CrossProcessMutex(const char*) {
// We explicitly share this using DuplicateHandle, we do -not- want this to
// be inherited by child processes by default! So no security attributes are
// given.
mMutex = ::CreateMutexA(nullptr, FALSE, nullptr);
if (!mMutex) {
MOZ_CRASH("This shouldn't happen - failed to create mutex!");
CrossProcessMutex::CrossProcessMutex(CrossProcessMutexHandle aHandle) {
DWORD flags;
if (!::GetHandleInformation(aHandle.get(), &flags)) {
MOZ_CRASH("Attempt to construct a mutex from an invalid handle!");
mMutex = aHandle.release();
CrossProcessMutex::~CrossProcessMutex() {
NS_ASSERTION(mMutex, "Improper construction of mutex or double free.");
void CrossProcessMutex::Lock() {
NS_ASSERTION(mMutex, "Improper construction of mutex.");
::WaitForSingleObject(mMutex, INFINITE);
void CrossProcessMutex::Unlock() {
NS_ASSERTION(mMutex, "Improper construction of mutex.");
CrossProcessMutexHandle CrossProcessMutex::CloneHandle() {
HANDLE newHandle;
if (!::DuplicateHandle(GetCurrentProcess(), mMutex, GetCurrentProcess(),
&newHandle, 0, false, DUPLICATE_SAME_ACCESS)) {
return nullptr;
return mozilla::UniqueFileHandle(newHandle);
} // namespace mozilla