1/*
2 * Copyright (C) 2014 Yoav Weiss (yoav@yoav.ws)
3 * Copyright (C) 2015 Akamai Technologies Inc. All rights reserved.
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Library General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Library General Public License for more details.
14 *
15 * You should have received a copy of the GNU Library General Public License
16 * along with this library; see the file COPYING.LIB. If not, write to
17 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
18 * Boston, MA 02110-1301, USA.
19 *
20 */
21
22#pragma once
23
24#include "Timer.h"
25#include <wtf/Forward.h>
26#include <wtf/Vector.h>
27
28namespace WebCore {
29
30class MicrotaskQueue;
31class ScriptExecutionContext;
32
33class Microtask {
34public:
35 virtual ~Microtask()
36 {
37 }
38
39 enum class Result {
40 Done,
41 KeepInQueue
42 };
43
44 virtual Result run() = 0;
45
46protected:
47 void removeSelfFromQueue(MicrotaskQueue&);
48};
49
50class VoidMicrotask final : public Microtask {
51 WTF_MAKE_FAST_ALLOCATED;
52public:
53 explicit VoidMicrotask(Function<void()>&& function)
54 : m_function(WTFMove(function))
55 {
56 }
57
58private:
59 Result run() final
60 {
61 m_function();
62 return Result::Done;
63 }
64
65 Function<void()> m_function;
66};
67
68class MicrotaskQueue {
69 friend NeverDestroyed<MicrotaskQueue>;
70 friend class Microtask;
71public:
72 WEBCORE_EXPORT static MicrotaskQueue& mainThreadQueue();
73 WEBCORE_EXPORT static MicrotaskQueue& contextQueue(ScriptExecutionContext&);
74
75 WEBCORE_EXPORT MicrotaskQueue();
76 WEBCORE_EXPORT ~MicrotaskQueue();
77
78 WEBCORE_EXPORT void append(std::unique_ptr<Microtask>&&);
79 WEBCORE_EXPORT void performMicrotaskCheckpoint();
80
81private:
82 WEBCORE_EXPORT void remove(const Microtask&);
83
84 void timerFired();
85
86 bool m_performingMicrotaskCheckpoint = false;
87 Vector<std::unique_ptr<Microtask>> m_microtaskQueue;
88
89 // FIXME: Instead of a Timer, we should have a centralized Event Loop that calls performMicrotaskCheckpoint()
90 // on every iteration, implementing https://html.spec.whatwg.org/multipage/webappapis.html#processing-model-9
91 Timer m_timer;
92};
93
94} // namespace WebCore
95