1/*
2 * Copyright (C) 2017 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. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include <wtf/Lock.h>
29#include <wtf/SharedTask.h>
30
31namespace JSC {
32
33template<typename OuterType, typename InnerType, typename UnwrapFunc>
34class ParallelSourceAdapter : public SharedTask<InnerType()> {
35public:
36 ParallelSourceAdapter(RefPtr<SharedTask<OuterType()>> outerSource, const UnwrapFunc& unwrapFunc)
37 : m_outerSource(outerSource)
38 , m_unwrapFunc(unwrapFunc)
39 {
40 }
41
42 InnerType run() override
43 {
44 auto locker = holdLock(m_lock);
45 do {
46 if (m_innerSource) {
47 if (InnerType result = m_innerSource->run())
48 return result;
49 m_innerSource = nullptr;
50 }
51
52 m_innerSource = m_unwrapFunc(m_outerSource->run());
53 } while (m_innerSource);
54 return InnerType();
55 }
56
57private:
58 RefPtr<SharedTask<OuterType()>> m_outerSource;
59 RefPtr<SharedTask<InnerType()>> m_innerSource;
60 UnwrapFunc m_unwrapFunc;
61 Lock m_lock;
62};
63
64template<typename OuterType, typename InnerType, typename UnwrapFunc>
65Ref<ParallelSourceAdapter<OuterType, InnerType, UnwrapFunc>> createParallelSourceAdapter(RefPtr<SharedTask<OuterType()>> outerSource, const UnwrapFunc& unwrapFunc)
66{
67 return adoptRef(*new ParallelSourceAdapter<OuterType, InnerType, UnwrapFunc>(outerSource, unwrapFunc));
68}
69
70} // namespace JSC
71
72