Merge remote-tracking branch 'remotes/cohuck-gitlab/tags/s390x-20210121' into staging
[qemu.git] / qobject / json-writer.c
1 /*
2 * JSON Writer
3 *
4 * Copyright IBM, Corp. 2009
5 * Copyright (c) 2010-2020 Red Hat Inc.
6 *
7 * Authors:
8 * Anthony Liguori <aliguori@us.ibm.com>
9 * Markus Armbruster <armbru@redhat.com>
10 *
11 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
12 * See the COPYING.LIB file in the top-level directory.
13 *
14 */
15
16 #include "qemu/osdep.h"
17 #include "qapi/qmp/json-writer.h"
18 #include "qemu/unicode.h"
19
20 struct JSONWriter {
21 bool pretty;
22 bool need_comma;
23 GString *contents;
24 GByteArray *container_is_array;
25 };
26
27 JSONWriter *json_writer_new(bool pretty)
28 {
29 JSONWriter *writer = g_new(JSONWriter, 1);
30
31 writer->pretty = pretty;
32 writer->need_comma = false;
33 writer->contents = g_string_new(NULL);
34 writer->container_is_array = g_byte_array_new();
35 return writer;
36 }
37
38 const char *json_writer_get(JSONWriter *writer)
39 {
40 g_assert(!writer->container_is_array->len);
41 return writer->contents->str;
42 }
43
44 GString *json_writer_get_and_free(JSONWriter *writer)
45 {
46 GString *contents = writer->contents;
47
48 writer->contents = NULL;
49 g_byte_array_free(writer->container_is_array, true);
50 g_free(writer);
51 return contents;
52 }
53
54 void json_writer_free(JSONWriter *writer)
55 {
56 if (writer) {
57 g_string_free(json_writer_get_and_free(writer), true);
58 }
59 }
60
61 static void enter_container(JSONWriter *writer, bool is_array)
62 {
63 unsigned depth = writer->container_is_array->len;
64
65 g_byte_array_set_size(writer->container_is_array, depth + 1);
66 writer->container_is_array->data[depth] = is_array;
67 writer->need_comma = false;
68 }
69
70 static void leave_container(JSONWriter *writer, bool is_array)
71 {
72 unsigned depth = writer->container_is_array->len;
73
74 assert(depth);
75 assert(writer->container_is_array->data[depth - 1] == is_array);
76 g_byte_array_set_size(writer->container_is_array, depth - 1);
77 writer->need_comma = true;
78 }
79
80 static bool in_object(JSONWriter *writer)
81 {
82 unsigned depth = writer->container_is_array->len;
83
84 return depth && !writer->container_is_array->data[depth - 1];
85 }
86
87 static void pretty_newline(JSONWriter *writer)
88 {
89 if (writer->pretty) {
90 g_string_append_printf(writer->contents, "\n%*s",
91 writer->container_is_array->len * 4, "");
92 }
93 }
94
95 static void pretty_newline_or_space(JSONWriter *writer)
96 {
97 if (writer->pretty) {
98 g_string_append_printf(writer->contents, "\n%*s",
99 writer->container_is_array->len * 4, "");
100 } else {
101 g_string_append_c(writer->contents, ' ');
102 }
103 }
104
105 static void quoted_str(JSONWriter *writer, const char *str)
106 {
107 const char *ptr;
108 char *end;
109 int cp;
110
111 g_string_append_c(writer->contents, '"');
112
113 for (ptr = str; *ptr; ptr = end) {
114 cp = mod_utf8_codepoint(ptr, 6, &end);
115 switch (cp) {
116 case '\"':
117 g_string_append(writer->contents, "\\\"");
118 break;
119 case '\\':
120 g_string_append(writer->contents, "\\\\");
121 break;
122 case '\b':
123 g_string_append(writer->contents, "\\b");
124 break;
125 case '\f':
126 g_string_append(writer->contents, "\\f");
127 break;
128 case '\n':
129 g_string_append(writer->contents, "\\n");
130 break;
131 case '\r':
132 g_string_append(writer->contents, "\\r");
133 break;
134 case '\t':
135 g_string_append(writer->contents, "\\t");
136 break;
137 default:
138 if (cp < 0) {
139 cp = 0xFFFD; /* replacement character */
140 }
141 if (cp > 0xFFFF) {
142 /* beyond BMP; need a surrogate pair */
143 g_string_append_printf(writer->contents, "\\u%04X\\u%04X",
144 0xD800 + ((cp - 0x10000) >> 10),
145 0xDC00 + ((cp - 0x10000) & 0x3FF));
146 } else if (cp < 0x20 || cp >= 0x7F) {
147 g_string_append_printf(writer->contents, "\\u%04X", cp);
148 } else {
149 g_string_append_c(writer->contents, cp);
150 }
151 }
152 };
153
154 g_string_append_c(writer->contents, '"');
155 }
156
157 static void maybe_comma_name(JSONWriter *writer, const char *name)
158 {
159 if (writer->need_comma) {
160 g_string_append_c(writer->contents, ',');
161 pretty_newline_or_space(writer);
162 } else {
163 if (writer->contents->len) {
164 pretty_newline(writer);
165 }
166 writer->need_comma = true;
167 }
168
169 if (in_object(writer)) {
170 quoted_str(writer, name);
171 g_string_append(writer->contents, ": ");
172 }
173 }
174
175 void json_writer_start_object(JSONWriter *writer, const char *name)
176 {
177 maybe_comma_name(writer, name);
178 g_string_append_c(writer->contents, '{');
179 enter_container(writer, false);
180 }
181
182 void json_writer_end_object(JSONWriter *writer)
183 {
184 leave_container(writer, false);
185 pretty_newline(writer);
186 g_string_append_c(writer->contents, '}');
187 }
188
189 void json_writer_start_array(JSONWriter *writer, const char *name)
190 {
191 maybe_comma_name(writer, name);
192 g_string_append_c(writer->contents, '[');
193 enter_container(writer, true);
194 }
195
196 void json_writer_end_array(JSONWriter *writer)
197 {
198 leave_container(writer, true);
199 pretty_newline(writer);
200 g_string_append_c(writer->contents, ']');
201 }
202
203 void json_writer_bool(JSONWriter *writer, const char *name, bool val)
204 {
205 maybe_comma_name(writer, name);
206 g_string_append(writer->contents, val ? "true" : "false");
207 }
208
209 void json_writer_null(JSONWriter *writer, const char *name)
210 {
211 maybe_comma_name(writer, name);
212 g_string_append(writer->contents, "null");
213 }
214
215 void json_writer_int64(JSONWriter *writer, const char *name, int64_t val)
216 {
217 maybe_comma_name(writer, name);
218 g_string_append_printf(writer->contents, "%" PRId64, val);
219 }
220
221 void json_writer_uint64(JSONWriter *writer, const char *name, uint64_t val)
222 {
223 maybe_comma_name(writer, name);
224 g_string_append_printf(writer->contents, "%" PRIu64, val);
225 }
226
227 void json_writer_double(JSONWriter *writer, const char *name, double val)
228 {
229 maybe_comma_name(writer, name);
230
231 /*
232 * FIXME: g_string_append_printf() is locale dependent; but JSON
233 * requires numbers to be formatted as if in the C locale.
234 * Dependence on C locale is a pervasive issue in QEMU.
235 */
236 /*
237 * FIXME: This risks printing Inf or NaN, which are not valid
238 * JSON values.
239 */
240 g_string_append_printf(writer->contents, "%.17g", val);
241 }
242
243 void json_writer_str(JSONWriter *writer, const char *name, const char *str)
244 {
245 maybe_comma_name(writer, name);
246 quoted_str(writer, str);
247 }