1/*
2 * Copyright (C) 2018 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include "GenericTaskQueue.h"
29
30namespace WebCore {
31
32template <typename T>
33class DeferrableTask : public CanMakeWeakPtr<DeferrableTask<T>> {
34public:
35 DeferrableTask()
36 : m_dispatcher()
37 {
38 }
39
40 DeferrableTask(T& t)
41 : m_dispatcher(t)
42 {
43 }
44
45 typedef WTF::Function<void ()> TaskFunction;
46
47 void scheduleTask(TaskFunction&& task)
48 {
49 if (m_isClosed)
50 return;
51
52 cancelTask();
53
54 m_pendingTask = true;
55 m_dispatcher.postTask([weakThis = makeWeakPtr(*this), task = WTFMove(task)] {
56 if (!weakThis)
57 return;
58 ASSERT(weakThis->m_pendingTask);
59 weakThis->m_pendingTask = false;
60 task();
61 });
62 }
63
64 void close()
65 {
66 cancelTask();
67 m_isClosed = true;
68 }
69
70 void cancelTask()
71 {
72 CanMakeWeakPtr<DeferrableTask<T>>::weakPtrFactory().revokeAll();
73 m_pendingTask = false;
74 }
75 bool hasPendingTask() const { return m_pendingTask; }
76
77private:
78 TaskDispatcher<T> m_dispatcher;
79 bool m_pendingTask { false };
80 bool m_isClosed { false };
81};
82
83}
84