gecko-dev/ipc/glue/CrossProcessMutex_windows.cpp

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
2012-05-21 11:12:37 +00:00
* 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 <windows.h>
#include "base/process_util.h"
#include "CrossProcessMutex.h"
#include "nsDebug.h"
#include "nsTraceRefcnt.h"
using namespace base;
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(NULL, FALSE, NULL);
if (!mMutex) {
NS_RUNTIMEABORT("This shouldn't happen - failed to create mutex!");
}
MOZ_COUNT_CTOR(CrossProcessMutex);
}
CrossProcessMutex::CrossProcessMutex(CrossProcessMutexHandle aHandle)
{
DWORD flags;
if (!::GetHandleInformation(aHandle, &flags)) {
NS_RUNTIMEABORT("Attempt to construct a mutex from an invalid handle!");
}
mMutex = aHandle;
MOZ_COUNT_CTOR(CrossProcessMutex);
}
CrossProcessMutex::~CrossProcessMutex()
{
NS_ASSERTION(mMutex, "Improper construction of mutex or double free.");
::CloseHandle(mMutex);
MOZ_COUNT_DTOR(CrossProcessMutex);
}
void
CrossProcessMutex::Lock()
{
NS_ASSERTION(mMutex, "Improper construction of mutex.");
::WaitForSingleObject(mMutex, INFINITE);
}
void
CrossProcessMutex::Unlock()
{
NS_ASSERTION(mMutex, "Improper construction of mutex.");
::ReleaseMutex(mMutex);
}
CrossProcessMutexHandle
CrossProcessMutex::ShareToProcess(ProcessHandle aHandle)
{
HANDLE newHandle;
bool succeeded = ::DuplicateHandle(GetCurrentProcessHandle(),
mMutex, aHandle, &newHandle,
0, FALSE, DUPLICATE_SAME_ACCESS);
if (!succeeded) {
return NULL;
}
return newHandle;
}
}