1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
|
/*
* Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/StringView.h>
#include <AK/Try.h>
#include <AK/Variant.h>
#if defined(AK_OS_SERENITY) && defined(KERNEL)
# include <LibC/errno_codes.h>
#else
# include <errno.h>
# include <string.h>
#endif
namespace AK {
class Error {
public:
static Error from_errno(int code) { return Error(code); }
static Error from_syscall(StringView syscall_name, int rc) { return Error(syscall_name, rc); }
static Error from_string_view(StringView string_literal) { return Error(string_literal); }
// NOTE: Prefer `from_string_literal` when directly typing out an error message:
//
// return Error::from_string_literal("Class: Some failure");
//
// If you need to return a static string based on a dynamic condition (like
// picking an error from an array), then prefer `from_string_view` instead.
template<size_t N>
ALWAYS_INLINE static Error from_string_literal(char const (&string_literal)[N])
{
return from_string_view(StringView { string_literal, N - 1 });
}
// Note: Don't call this from C++; it's here for Jakt interop (as the name suggests).
template<SameAs<StringView> T>
ALWAYS_INLINE static Error __jakt_from_string_literal(T string)
{
return from_string_view(string);
}
bool operator==(Error const& other) const
{
return m_code == other.m_code && m_string_literal == other.m_string_literal && m_syscall == other.m_syscall;
}
bool is_errno() const { return m_code != 0; }
bool is_syscall() const { return m_syscall; }
int code() const { return m_code; }
StringView string_literal() const { return m_string_literal; }
protected:
Error(int code)
: m_code(code)
{
}
private:
Error(StringView string_literal)
: m_string_literal(string_literal)
{
}
Error(StringView syscall_name, int rc)
: m_string_literal(syscall_name)
, m_code(-rc)
, m_syscall(true)
{
}
StringView m_string_literal;
int m_code { 0 };
bool m_syscall { false };
};
template<typename T, typename E>
class [[nodiscard]] ErrorOr {
public:
using ResultType = T;
using ErrorType = E;
ErrorOr()
requires(IsSame<T, Empty>)
: m_value_or_error(Empty {})
{
}
ALWAYS_INLINE ErrorOr(ErrorOr&&) = default;
ALWAYS_INLINE ErrorOr(ErrorOr const&) = default;
ALWAYS_INLINE ErrorOr& operator=(ErrorOr&&) = default;
ALWAYS_INLINE ErrorOr& operator=(ErrorOr const&) = default;
template<typename U>
ALWAYS_INLINE ErrorOr(ErrorOr<U, ErrorType> const& value)
: m_value_or_error(value.m_value_or_error.visit([](U const& v) -> Variant<T, ErrorType> { return v; }, [](ErrorType const& error) -> Variant<T, ErrorType> { return error; }))
{
}
template<typename U>
ALWAYS_INLINE ErrorOr(ErrorOr<U, ErrorType>& value)
: m_value_or_error(value.m_value_or_error.visit([](U& v) { return Variant<T, ErrorType>(move(v)); }, [](ErrorType& error) { return Variant<T, ErrorType>(move(error)); }))
{
}
template<typename U>
ALWAYS_INLINE ErrorOr(ErrorOr<U, ErrorType>&& value)
: m_value_or_error(value.visit([](U& v) { return Variant<T, ErrorType>(move(v)); }, [](ErrorType& error) { return Variant<T, ErrorType>(move(error)); }))
{
}
template<typename U>
ALWAYS_INLINE ErrorOr(U&& value)
requires(
requires { T(declval<U>()); } || requires { ErrorType(declval<RemoveCVReference<U>>()); })
: m_value_or_error(forward<U>(value))
{
}
#ifdef AK_OS_SERENITY
ErrorOr(ErrnoCode code)
: m_value_or_error(Error::from_errno(code))
{
}
#endif
T& value()
{
return m_value_or_error.template get<T>();
}
T const& value() const { return m_value_or_error.template get<T>(); }
ErrorType& error() { return m_value_or_error.template get<ErrorType>(); }
ErrorType const& error() const { return m_value_or_error.template get<ErrorType>(); }
bool is_error() const { return m_value_or_error.template has<ErrorType>(); }
T release_value() { return move(value()); }
ErrorType release_error() { return move(error()); }
T release_value_but_fixme_should_propagate_errors()
{
VERIFY(!is_error());
return release_value();
}
private:
Variant<T, ErrorType> m_value_or_error;
};
template<typename ErrorType>
class [[nodiscard]] ErrorOr<void, ErrorType> : public ErrorOr<Empty, ErrorType> {
public:
using ResultType = void;
using ErrorOr<Empty, ErrorType>::ErrorOr;
};
}
#if USING_AK_GLOBALLY
using AK::Error;
using AK::ErrorOr;
#endif
|
