| // Copyright (c) 2011 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "base/synchronization/waitable_event_watcher.h" |
| |
| #include "base/compiler_specific.h" |
| #include "base/synchronization/waitable_event.h" |
| #include "base/win/object_watcher.h" |
| |
| namespace base { |
| |
| WaitableEventWatcher::WaitableEventWatcher() = default; |
| |
| WaitableEventWatcher::~WaitableEventWatcher() {} |
| |
| bool WaitableEventWatcher::StartWatching(WaitableEvent* event, |
| EventCallback callback) { |
| DCHECK(event); |
| callback_ = std::move(callback); |
| event_ = event; |
| |
| // Duplicate and hold the event handle until a callback is returned or |
| // waiting is stopped. |
| HANDLE handle = nullptr; |
| if (!::DuplicateHandle(::GetCurrentProcess(), // hSourceProcessHandle |
| event->handle(), |
| ::GetCurrentProcess(), // hTargetProcessHandle |
| &handle, |
| 0, // dwDesiredAccess ignored due to SAME_ACCESS |
| FALSE, // !bInheritHandle |
| DUPLICATE_SAME_ACCESS)) { |
| return false; |
| } |
| duplicated_event_handle_.Set(handle); |
| return watcher_.StartWatchingOnce(handle, this); |
| } |
| |
| void WaitableEventWatcher::StopWatching() { |
| callback_.Reset(); |
| event_ = NULL; |
| watcher_.StopWatching(); |
| duplicated_event_handle_.Close(); |
| } |
| |
| void WaitableEventWatcher::OnObjectSignaled(HANDLE h) { |
| DCHECK_EQ(duplicated_event_handle_.Get(), h); |
| WaitableEvent* event = event_; |
| EventCallback callback = std::move(callback_); |
| event_ = NULL; |
| duplicated_event_handle_.Close(); |
| DCHECK(event); |
| |
| std::move(callback).Run(event); |
| } |
| |
| } // namespace base |