jcs.org
Serenity Operating System
1/*
2 * Copyright (C) 2016 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 "Assertions.h"
29#include "OwnPtr.h"
30#include "StdLibExtras.h"
31
32namespace AK {
33
34template<typename>
35class Function;
36
37template<typename Out, typename... In>
38class Function<Out(In...)> {
39public:
40 Function() = default;
41 Function(std::nullptr_t) {}
42
43 template<typename CallableType, class = typename EnableIf<!(IsPointer<CallableType>::value && IsFunction<typename RemovePointer<CallableType>::Type>::value) && IsRvalueReference<CallableType&&>::value>::Type>
44 Function(CallableType&& callable)
45 : m_callable_wrapper(make<CallableWrapper<CallableType>>(move(callable)))
46 {
47 }
48
49 template<typename FunctionType, class = typename EnableIf<IsPointer<FunctionType>::value && IsFunction<typename RemovePointer<FunctionType>::Type>::value>::Type>
50 Function(FunctionType f)
51 : m_callable_wrapper(make<CallableWrapper<FunctionType>>(move(f)))
52 {
53 }
54
55 Out operator()(In... in) const
56 {
57 ASSERT(m_callable_wrapper);
58 return m_callable_wrapper->call(forward<In>(in)...);
59 }
60
61 explicit operator bool() const { return !!m_callable_wrapper; }
62
63 template<typename CallableType, class = typename EnableIf<!(IsPointer<CallableType>::value && IsFunction<typename RemovePointer<CallableType>::Type>::value) && IsRvalueReference<CallableType&&>::value>::Type>
64 Function& operator=(CallableType&& callable)
65 {
66 m_callable_wrapper = make<CallableWrapper<CallableType>>(move(callable));
67 return *this;
68 }
69
70 template<typename FunctionType, class = typename EnableIf<IsPointer<FunctionType>::value && IsFunction<typename RemovePointer<FunctionType>::Type>::value>::Type>
71 Function& operator=(FunctionType f)
72 {
73 m_callable_wrapper = make<CallableWrapper<FunctionType>>(move(f));
74 return *this;
75 }
76
77 Function& operator=(std::nullptr_t)
78 {
79 m_callable_wrapper = nullptr;
80 return *this;
81 }
82
83private:
84 class CallableWrapperBase {
85 public:
86 virtual ~CallableWrapperBase() {}
87 virtual Out call(In...) const = 0;
88 };
89
90 template<typename CallableType>
91 class CallableWrapper final : public CallableWrapperBase {
92 public:
93 explicit CallableWrapper(CallableType&& callable)
94 : m_callable(move(callable))
95 {
96 }
97
98 CallableWrapper(const CallableWrapper&) = delete;
99 CallableWrapper& operator=(const CallableWrapper&) = delete;
100
101 Out call(In... in) const final override { return m_callable(forward<In>(in)...); }
102
103 private:
104 CallableType m_callable;
105 };
106
107 OwnPtr<CallableWrapperBase> m_callable_wrapper;
108};
109
110}
111
112using AK::Function;