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