michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include <windows.h>
michael@0: 
michael@0: #include "base/process_util.h"
michael@0: #include "CrossProcessMutex.h"
michael@0: #include "nsDebug.h"
michael@0: #include "nsISupportsImpl.h"
michael@0: 
michael@0: using namespace base;
michael@0: 
michael@0: namespace mozilla {
michael@0: 
michael@0: CrossProcessMutex::CrossProcessMutex(const char*)
michael@0: {
michael@0:   // We explicitly share this using DuplicateHandle, we do -not- want this to
michael@0:   // be inherited by child processes by default! So no security attributes are
michael@0:   // given.
michael@0:   mMutex = ::CreateMutexA(nullptr, FALSE, nullptr);
michael@0:   if (!mMutex) {
michael@0:     NS_RUNTIMEABORT("This shouldn't happen - failed to create mutex!");
michael@0:   }
michael@0:   MOZ_COUNT_CTOR(CrossProcessMutex);
michael@0: }
michael@0: 
michael@0: CrossProcessMutex::CrossProcessMutex(CrossProcessMutexHandle aHandle)
michael@0: {
michael@0:   DWORD flags;
michael@0:   if (!::GetHandleInformation(aHandle, &flags)) {
michael@0:     NS_RUNTIMEABORT("Attempt to construct a mutex from an invalid handle!");
michael@0:   }
michael@0:   mMutex = aHandle;
michael@0:   MOZ_COUNT_CTOR(CrossProcessMutex);
michael@0: }
michael@0: 
michael@0: CrossProcessMutex::~CrossProcessMutex()
michael@0: {
michael@0:   NS_ASSERTION(mMutex, "Improper construction of mutex or double free.");
michael@0:   ::CloseHandle(mMutex);
michael@0:   MOZ_COUNT_DTOR(CrossProcessMutex);
michael@0: }
michael@0: 
michael@0: void
michael@0: CrossProcessMutex::Lock()
michael@0: {
michael@0:   NS_ASSERTION(mMutex, "Improper construction of mutex.");
michael@0:   ::WaitForSingleObject(mMutex, INFINITE);
michael@0: }
michael@0: 
michael@0: void
michael@0: CrossProcessMutex::Unlock()
michael@0: {
michael@0:   NS_ASSERTION(mMutex, "Improper construction of mutex.");
michael@0:   ::ReleaseMutex(mMutex);
michael@0: }
michael@0: 
michael@0: CrossProcessMutexHandle
michael@0: CrossProcessMutex::ShareToProcess(ProcessHandle aHandle)
michael@0: {
michael@0:   HANDLE newHandle;
michael@0:   bool succeeded = ::DuplicateHandle(GetCurrentProcessHandle(),
michael@0:                                      mMutex, aHandle, &newHandle,
michael@0:                                      0, FALSE, DUPLICATE_SAME_ACCESS);
michael@0: 
michael@0:   if (!succeeded) {
michael@0:     return nullptr;
michael@0:   }
michael@0: 
michael@0:   return newHandle;
michael@0: }
michael@0: 
michael@0: }