1 /* JSON trees
2 Copyright (C) 2017-2023 Free Software Foundation, Inc.
3 Contributed by David Malcolm <dmalcolm@redhat.com>.
4
5 This file is part of GCC.
6
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
10 version.
11
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
20
21 #ifndef GCC_JSON_H
22 #define GCC_JSON_H
23
24 /* Implementation of JSON, a lightweight data-interchange format.
25
26 See http://www.json.org/
27 and http://www.ecma-international.org/publications/files/ECMA-ST/ECMA-404.pdf
28 and https://tools.ietf.org/html/rfc7159
29
30 Supports creating a DOM-like tree of json::value *, and then dumping
31 json::value * to text. */
32
33 namespace json
34 {
35
36 /* Forward decls of json::value and its subclasses (using indentation
37 to denote inheritance. */
38
39 class value;
40 class object;
41 class array;
42 class float_number;
43 class integer_number;
44 class string;
45 class literal;
46
47 /* An enum for discriminating the subclasses of json::value. */
48
49 enum kind
50 {
51 /* class json::object. */
52 JSON_OBJECT,
53
54 /* class json::array. */
55 JSON_ARRAY,
56
57 /* class json::integer_number. */
58 JSON_INTEGER,
59
60 /* class json::float_number. */
61 JSON_FLOAT,
62
63 /* class json::string. */
64 JSON_STRING,
65
66 /* class json::literal uses these three values to identify the
67 particular literal. */
68 JSON_TRUE,
69 JSON_FALSE,
70 JSON_NULL
71 };
72
73 /* Base class of JSON value. */
74
75 class value
76 {
77 public:
78 virtual ~value () {}
79 virtual enum kind get_kind () const = 0;
80 virtual void print (pretty_printer *pp) const = 0;
81
82 void dump (FILE *) const;
83 };
84
85 /* Subclass of value for objects: a collection of key/value pairs
86 preserving the ordering in which keys were inserted.
87
88 Preserving the order eliminates non-determinism in the output,
89 making it easier for the user to compare repeated invocations. */
90
91 class object : public value
92 {
93 public:
94 ~object ();
95
96 enum kind get_kind () const final override { return JSON_OBJECT; }
97 void print (pretty_printer *pp) const final override;
98
99 void set (const char *key, value *v);
100 value *get (const char *key) const;
101
102 private:
103 typedef hash_map <char *, value *,
104 simple_hashmap_traits<nofree_string_hash, value *> > map_t;
105 map_t m_map;
106
107 /* Keep track of order in which keys were inserted. */
108 auto_vec <const char *> m_keys;
109 };
110
111 /* Subclass of value for arrays. */
112
113 class array : public value
114 {
115 public:
116 ~array ();
117
118 enum kind get_kind () const final override { return JSON_ARRAY; }
119 void print (pretty_printer *pp) const final override;
120
121 void append (value *v);
122
123 private:
124 auto_vec<value *> m_elements;
125 };
126
127 /* Subclass of value for floating-point numbers. */
128
129 class float_number : public value
130 {
131 public:
132 float_number (double value) : m_value (value) {}
133
134 enum kind get_kind () const final override { return JSON_FLOAT; }
135 void print (pretty_printer *pp) const final override;
136
137 double get () const { return m_value; }
138
139 private:
140 double m_value;
141 };
142
143 /* Subclass of value for integer-valued numbers. */
144
145 class integer_number : public value
146 {
147 public:
148 integer_number (long value) : m_value (value) {}
149
150 enum kind get_kind () const final override { return JSON_INTEGER; }
151 void print (pretty_printer *pp) const final override;
152
153 long get () const { return m_value; }
154
155 private:
156 long m_value;
157 };
158
159
160 /* Subclass of value for strings. */
161
162 class string : public value
163 {
164 public:
165 explicit string (const char *utf8);
166 string (const char *utf8, size_t len);
167 ~string () { free (m_utf8); }
168
169 enum kind get_kind () const final override { return JSON_STRING; }
170 void print (pretty_printer *pp) const final override;
171
172 const char *get_string () const { return m_utf8; }
173 size_t get_length () const { return m_len; }
174
175 private:
176 char *m_utf8;
177 size_t m_len;
178 };
179
180 /* Subclass of value for the three JSON literals "true", "false",
181 and "null". */
182
183 class literal : public value
184 {
185 public:
186 literal (enum kind kind) : m_kind (kind) {}
187
188 /* Construct literal for a boolean value. */
189 literal (bool value): m_kind (value ? JSON_TRUE : JSON_FALSE) {}
190
191 enum kind get_kind () const final override { return m_kind; }
192 void print (pretty_printer *pp) const final override;
193
194 private:
195 enum kind m_kind;
196 };
197
198 } // namespace json
199
200 #endif /* GCC_JSON_H */