1 | /* |
2 | |
3 | Copyright (C) 2016-2017 Apple Inc. All rights reserved. |
4 | |
5 | Redistribution and use in source and binary forms, with or without |
6 | modification, are permitted provided that the following conditions |
7 | are met: |
8 | 1. Redistributions of source code must retain the above copyright |
9 | notice, this list of conditions and the following disclaimer. |
10 | 2. Redistributions in binary form must reproduce the above copyright |
11 | notice, this list of conditions and the following disclaimer in the |
12 | documentation and/or other materials provided with the distribution. |
13 | |
14 | THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY |
15 | EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
16 | WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
17 | DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY |
18 | DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
19 | (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
20 | LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON |
21 | ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
22 | (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
23 | SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
24 | |
25 | */ |
26 | |
27 | #pragma once |
28 | |
29 | #include "Exception.h" |
30 | #include <wtf/CrossThreadCopier.h> |
31 | #include <wtf/Expected.h> |
32 | |
33 | namespace WebCore { |
34 | |
35 | template<typename ReturnType> class ExceptionOr { |
36 | public: |
37 | ExceptionOr(Exception&&); |
38 | ExceptionOr(ReturnType&&); |
39 | template<typename OtherType> ExceptionOr(const OtherType&, typename std::enable_if<std::is_scalar<OtherType>::value && std::is_convertible<OtherType, ReturnType>::value>::type* = nullptr); |
40 | |
41 | bool hasException() const; |
42 | const Exception& exception() const; |
43 | Exception&& releaseException(); |
44 | const ReturnType& returnValue() const; |
45 | ReturnType&& releaseReturnValue(); |
46 | |
47 | private: |
48 | Expected<ReturnType, Exception> m_value; |
49 | }; |
50 | |
51 | template<typename ReturnReferenceType> class ExceptionOr<ReturnReferenceType&> { |
52 | public: |
53 | ExceptionOr(Exception&&); |
54 | ExceptionOr(ReturnReferenceType&); |
55 | |
56 | bool hasException() const; |
57 | const Exception& exception() const; |
58 | Exception&& releaseException(); |
59 | const ReturnReferenceType& returnValue() const; |
60 | ReturnReferenceType& releaseReturnValue(); |
61 | |
62 | private: |
63 | ExceptionOr<ReturnReferenceType*> m_value; |
64 | }; |
65 | |
66 | template<> class ExceptionOr<void> { |
67 | public: |
68 | ExceptionOr(Exception&&); |
69 | ExceptionOr() = default; |
70 | |
71 | bool hasException() const; |
72 | const Exception& exception() const; |
73 | Exception&& releaseException(); |
74 | |
75 | private: |
76 | Expected<void, Exception> m_value; |
77 | }; |
78 | |
79 | ExceptionOr<void> isolatedCopy(ExceptionOr<void>&&); |
80 | |
81 | template<typename ReturnType> inline ExceptionOr<ReturnType>::ExceptionOr(Exception&& exception) |
82 | : m_value(makeUnexpected(WTFMove(exception))) |
83 | { |
84 | } |
85 | |
86 | template<typename ReturnType> inline ExceptionOr<ReturnType>::ExceptionOr(ReturnType&& returnValue) |
87 | : m_value(WTFMove(returnValue)) |
88 | { |
89 | } |
90 | |
91 | template<typename ReturnType> template<typename OtherType> inline ExceptionOr<ReturnType>::ExceptionOr(const OtherType& returnValue, typename std::enable_if<std::is_scalar<OtherType>::value && std::is_convertible<OtherType, ReturnType>::value>::type*) |
92 | : m_value(static_cast<ReturnType>(returnValue)) |
93 | { |
94 | } |
95 | |
96 | template<typename ReturnType> inline bool ExceptionOr<ReturnType>::hasException() const |
97 | { |
98 | return !m_value.has_value(); |
99 | } |
100 | |
101 | template<typename ReturnType> inline const Exception& ExceptionOr<ReturnType>::exception() const |
102 | { |
103 | return m_value.error(); |
104 | } |
105 | |
106 | template<typename ReturnType> inline Exception&& ExceptionOr<ReturnType>::releaseException() |
107 | { |
108 | return WTFMove(m_value.error()); |
109 | } |
110 | |
111 | template<typename ReturnType> inline const ReturnType& ExceptionOr<ReturnType>::returnValue() const |
112 | { |
113 | return m_value.value(); |
114 | } |
115 | |
116 | template<typename ReturnType> inline ReturnType&& ExceptionOr<ReturnType>::releaseReturnValue() |
117 | { |
118 | return WTFMove(m_value.value()); |
119 | } |
120 | |
121 | template<typename ReturnReferenceType> inline ExceptionOr<ReturnReferenceType&>::ExceptionOr(Exception&& exception) |
122 | : m_value(WTFMove(exception)) |
123 | { |
124 | } |
125 | |
126 | template<typename ReturnReferenceType> inline ExceptionOr<ReturnReferenceType&>::ExceptionOr(ReturnReferenceType& returnValue) |
127 | : m_value(&returnValue) |
128 | { |
129 | } |
130 | |
131 | template<typename ReturnReferenceType> inline bool ExceptionOr<ReturnReferenceType&>::hasException() const |
132 | { |
133 | return m_value.hasException(); |
134 | } |
135 | |
136 | template<typename ReturnReferenceType> inline const Exception& ExceptionOr<ReturnReferenceType&>::exception() const |
137 | { |
138 | return m_value.exception(); |
139 | } |
140 | |
141 | template<typename ReturnReferenceType> inline Exception&& ExceptionOr<ReturnReferenceType&>::releaseException() |
142 | { |
143 | return m_value.releaseException(); |
144 | } |
145 | |
146 | template<typename ReturnReferenceType> inline const ReturnReferenceType& ExceptionOr<ReturnReferenceType&>::returnValue() const |
147 | { |
148 | return *m_value.returnValue(); |
149 | } |
150 | |
151 | template<typename ReturnReferenceType> inline ReturnReferenceType& ExceptionOr<ReturnReferenceType&>::releaseReturnValue() |
152 | { |
153 | return *m_value.releaseReturnValue(); |
154 | } |
155 | |
156 | inline ExceptionOr<void>::ExceptionOr(Exception&& exception) |
157 | : m_value(makeUnexpected(WTFMove(exception))) |
158 | { |
159 | } |
160 | |
161 | inline bool ExceptionOr<void>::hasException() const |
162 | { |
163 | return !m_value.has_value(); |
164 | } |
165 | |
166 | inline const Exception& ExceptionOr<void>::exception() const |
167 | { |
168 | return m_value.error(); |
169 | } |
170 | |
171 | inline Exception&& ExceptionOr<void>::releaseException() |
172 | { |
173 | return WTFMove(m_value.error()); |
174 | } |
175 | |
176 | inline ExceptionOr<void> isolatedCopy(ExceptionOr<void>&& value) |
177 | { |
178 | if (value.hasException()) |
179 | return isolatedCopy(value.releaseException()); |
180 | return { }; |
181 | } |
182 | |
183 | } |
184 | |
185 | namespace WTF { |
186 | template<typename T> struct CrossThreadCopierBase<false, false, WebCore::ExceptionOr<T> > { |
187 | typedef WebCore::ExceptionOr<T> Type; |
188 | static Type copy(const Type& source) |
189 | { |
190 | if (source.hasException()) |
191 | return crossThreadCopy(source.exception()); |
192 | return crossThreadCopy(source.returnValue()); |
193 | } |
194 | }; |
195 | } |
196 | |