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Commit | Line | Data |
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d9d8c839 | 1 | /* SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) */ |
fcc16c22 SH |
2 | /* |
3 | * Simple streaming JSON writer | |
4 | * | |
5 | * This takes care of the annoying bits of JSON syntax like the commas | |
6 | * after elements | |
7 | * | |
fcc16c22 SH |
8 | * Authors: Stephen Hemminger <stephen@networkplumber.org> |
9 | */ | |
10 | ||
11 | #include <stdio.h> | |
12 | #include <stdbool.h> | |
13 | #include <stdarg.h> | |
14 | #include <assert.h> | |
15 | #include <malloc.h> | |
16 | #include <inttypes.h> | |
17 | #include <stdint.h> | |
18 | ||
19 | #include "json_writer.h" | |
20 | ||
21 | struct json_writer { | |
22 | FILE *out; /* output file */ | |
23 | unsigned depth; /* nesting */ | |
24 | bool pretty; /* optional whitepace */ | |
25 | char sep; /* either nul or comma */ | |
26 | }; | |
27 | ||
28 | /* indentation for pretty print */ | |
29 | static void jsonw_indent(json_writer_t *self) | |
30 | { | |
31 | unsigned i; | |
d721a145 | 32 | for (i = 0; i < self->depth; ++i) |
fcc16c22 SH |
33 | fputs(" ", self->out); |
34 | } | |
35 | ||
36 | /* end current line and indent if pretty printing */ | |
37 | static void jsonw_eol(json_writer_t *self) | |
38 | { | |
39 | if (!self->pretty) | |
40 | return; | |
41 | ||
42 | putc('\n', self->out); | |
43 | jsonw_indent(self); | |
44 | } | |
45 | ||
46 | /* If current object is not empty print a comma */ | |
47 | static void jsonw_eor(json_writer_t *self) | |
48 | { | |
49 | if (self->sep != '\0') | |
50 | putc(self->sep, self->out); | |
51 | self->sep = ','; | |
52 | } | |
53 | ||
54 | ||
55 | /* Output JSON encoded string */ | |
56 | /* Handles C escapes, does not do Unicode */ | |
57 | static void jsonw_puts(json_writer_t *self, const char *str) | |
58 | { | |
59 | putc('"', self->out); | |
60 | for (; *str; ++str) | |
61 | switch (*str) { | |
62 | case '\t': | |
63 | fputs("\\t", self->out); | |
64 | break; | |
65 | case '\n': | |
66 | fputs("\\n", self->out); | |
67 | break; | |
68 | case '\r': | |
69 | fputs("\\r", self->out); | |
70 | break; | |
71 | case '\f': | |
72 | fputs("\\f", self->out); | |
73 | break; | |
74 | case '\b': | |
75 | fputs("\\b", self->out); | |
76 | break; | |
77 | case '\\': | |
ed54f764 | 78 | fputs("\\\\", self->out); |
fcc16c22 SH |
79 | break; |
80 | case '"': | |
81 | fputs("\\\"", self->out); | |
82 | break; | |
83 | case '\'': | |
84 | fputs("\\\'", self->out); | |
85 | break; | |
86 | default: | |
87 | putc(*str, self->out); | |
88 | } | |
89 | putc('"', self->out); | |
90 | } | |
91 | ||
92 | /* Create a new JSON stream */ | |
93 | json_writer_t *jsonw_new(FILE *f) | |
94 | { | |
95 | json_writer_t *self = malloc(sizeof(*self)); | |
96 | if (self) { | |
97 | self->out = f; | |
98 | self->depth = 0; | |
99 | self->pretty = false; | |
100 | self->sep = '\0'; | |
fcc16c22 SH |
101 | } |
102 | return self; | |
103 | } | |
104 | ||
105 | /* End output to JSON stream */ | |
106 | void jsonw_destroy(json_writer_t **self_p) | |
107 | { | |
108 | json_writer_t *self = *self_p; | |
109 | ||
110 | assert(self->depth == 0); | |
d721a145 | 111 | fputs("\n", self->out); |
fcc16c22 SH |
112 | fflush(self->out); |
113 | free(self); | |
114 | *self_p = NULL; | |
115 | } | |
116 | ||
117 | void jsonw_pretty(json_writer_t *self, bool on) | |
118 | { | |
119 | self->pretty = on; | |
120 | } | |
121 | ||
122 | /* Basic blocks */ | |
123 | static void jsonw_begin(json_writer_t *self, int c) | |
124 | { | |
125 | jsonw_eor(self); | |
126 | putc(c, self->out); | |
127 | ++self->depth; | |
128 | self->sep = '\0'; | |
129 | } | |
130 | ||
131 | static void jsonw_end(json_writer_t *self, int c) | |
132 | { | |
133 | assert(self->depth > 0); | |
134 | ||
135 | --self->depth; | |
136 | if (self->sep != '\0') | |
137 | jsonw_eol(self); | |
138 | putc(c, self->out); | |
139 | self->sep = ','; | |
140 | } | |
141 | ||
142 | ||
143 | /* Add a JSON property name */ | |
144 | void jsonw_name(json_writer_t *self, const char *name) | |
145 | { | |
146 | jsonw_eor(self); | |
147 | jsonw_eol(self); | |
148 | self->sep = '\0'; | |
149 | jsonw_puts(self, name); | |
150 | putc(':', self->out); | |
151 | if (self->pretty) | |
152 | putc(' ', self->out); | |
153 | } | |
154 | ||
5d5586b0 | 155 | __attribute__((format(printf, 2, 3))) |
7252f16b | 156 | void jsonw_printf(json_writer_t *self, const char *fmt, ...) |
fcc16c22 SH |
157 | { |
158 | va_list ap; | |
159 | ||
160 | va_start(ap, fmt); | |
161 | jsonw_eor(self); | |
162 | vfprintf(self->out, fmt, ap); | |
163 | va_end(ap); | |
164 | } | |
165 | ||
166 | /* Collections */ | |
167 | void jsonw_start_object(json_writer_t *self) | |
168 | { | |
169 | jsonw_begin(self, '{'); | |
170 | } | |
171 | ||
172 | void jsonw_end_object(json_writer_t *self) | |
173 | { | |
174 | jsonw_end(self, '}'); | |
175 | } | |
176 | ||
177 | void jsonw_start_array(json_writer_t *self) | |
178 | { | |
179 | jsonw_begin(self, '['); | |
6cbd9465 SH |
180 | if (self->pretty) |
181 | putc(' ', self->out); | |
fcc16c22 SH |
182 | } |
183 | ||
184 | void jsonw_end_array(json_writer_t *self) | |
185 | { | |
6cbd9465 SH |
186 | if (self->pretty && self->sep) |
187 | putc(' ', self->out); | |
188 | self->sep = '\0'; | |
fcc16c22 SH |
189 | jsonw_end(self, ']'); |
190 | } | |
191 | ||
192 | /* JSON value types */ | |
193 | void jsonw_string(json_writer_t *self, const char *value) | |
194 | { | |
195 | jsonw_eor(self); | |
196 | jsonw_puts(self, value); | |
197 | } | |
198 | ||
199 | void jsonw_bool(json_writer_t *self, bool val) | |
200 | { | |
201 | jsonw_printf(self, "%s", val ? "true" : "false"); | |
202 | } | |
203 | ||
fcc16c22 SH |
204 | void jsonw_null(json_writer_t *self) |
205 | { | |
206 | jsonw_printf(self, "null"); | |
207 | } | |
208 | ||
209 | void jsonw_float(json_writer_t *self, double num) | |
210 | { | |
211 | jsonw_printf(self, "%g", num); | |
212 | } | |
fcc16c22 | 213 | |
b640e85d JK |
214 | void jsonw_hhu(json_writer_t *self, unsigned char num) |
215 | { | |
216 | jsonw_printf(self, "%hhu", num); | |
217 | } | |
218 | ||
7252f16b JF |
219 | void jsonw_hu(json_writer_t *self, unsigned short num) |
220 | { | |
221 | jsonw_printf(self, "%hu", num); | |
222 | } | |
223 | ||
4db2ff0d THJ |
224 | void jsonw_uint(json_writer_t *self, unsigned int num) |
225 | { | |
226 | jsonw_printf(self, "%u", num); | |
227 | } | |
228 | ||
229 | void jsonw_u64(json_writer_t *self, uint64_t num) | |
fcc16c22 SH |
230 | { |
231 | jsonw_printf(self, "%"PRIu64, num); | |
232 | } | |
233 | ||
8958a15c SW |
234 | void jsonw_xint(json_writer_t *self, uint64_t num) |
235 | { | |
236 | jsonw_printf(self, "%"PRIx64, num); | |
237 | } | |
238 | ||
3a1f602a | 239 | void jsonw_luint(json_writer_t *self, unsigned long num) |
4db2ff0d THJ |
240 | { |
241 | jsonw_printf(self, "%lu", num); | |
242 | } | |
243 | ||
3a1f602a | 244 | void jsonw_lluint(json_writer_t *self, unsigned long long num) |
7252f16b JF |
245 | { |
246 | jsonw_printf(self, "%llu", num); | |
247 | } | |
248 | ||
4db2ff0d THJ |
249 | void jsonw_int(json_writer_t *self, int num) |
250 | { | |
251 | jsonw_printf(self, "%d", num); | |
252 | } | |
253 | ||
254 | void jsonw_s64(json_writer_t *self, int64_t num) | |
fcc16c22 SH |
255 | { |
256 | jsonw_printf(self, "%"PRId64, num); | |
257 | } | |
258 | ||
259 | /* Basic name/value objects */ | |
260 | void jsonw_string_field(json_writer_t *self, const char *prop, const char *val) | |
261 | { | |
262 | jsonw_name(self, prop); | |
263 | jsonw_string(self, val); | |
264 | } | |
265 | ||
266 | void jsonw_bool_field(json_writer_t *self, const char *prop, bool val) | |
267 | { | |
268 | jsonw_name(self, prop); | |
269 | jsonw_bool(self, val); | |
270 | } | |
271 | ||
fcc16c22 SH |
272 | void jsonw_float_field(json_writer_t *self, const char *prop, double val) |
273 | { | |
274 | jsonw_name(self, prop); | |
275 | jsonw_float(self, val); | |
276 | } | |
fcc16c22 | 277 | |
4db2ff0d | 278 | void jsonw_uint_field(json_writer_t *self, const char *prop, unsigned int num) |
fcc16c22 SH |
279 | { |
280 | jsonw_name(self, prop); | |
281 | jsonw_uint(self, num); | |
282 | } | |
283 | ||
4db2ff0d THJ |
284 | void jsonw_u64_field(json_writer_t *self, const char *prop, uint64_t num) |
285 | { | |
286 | jsonw_name(self, prop); | |
287 | jsonw_u64(self, num); | |
288 | } | |
289 | ||
8958a15c SW |
290 | void jsonw_xint_field(json_writer_t *self, const char *prop, uint64_t num) |
291 | { | |
292 | jsonw_name(self, prop); | |
293 | jsonw_xint(self, num); | |
294 | } | |
295 | ||
b640e85d JK |
296 | void jsonw_hhu_field(json_writer_t *self, const char *prop, unsigned char num) |
297 | { | |
298 | jsonw_name(self, prop); | |
299 | jsonw_hhu(self, num); | |
300 | } | |
301 | ||
7252f16b JF |
302 | void jsonw_hu_field(json_writer_t *self, const char *prop, unsigned short num) |
303 | { | |
304 | jsonw_name(self, prop); | |
305 | jsonw_hu(self, num); | |
306 | } | |
307 | ||
4db2ff0d THJ |
308 | void jsonw_luint_field(json_writer_t *self, |
309 | const char *prop, | |
3a1f602a | 310 | unsigned long num) |
4db2ff0d THJ |
311 | { |
312 | jsonw_name(self, prop); | |
313 | jsonw_luint(self, num); | |
314 | } | |
315 | ||
7252f16b JF |
316 | void jsonw_lluint_field(json_writer_t *self, |
317 | const char *prop, | |
3a1f602a | 318 | unsigned long long num) |
7252f16b JF |
319 | { |
320 | jsonw_name(self, prop); | |
321 | jsonw_lluint(self, num); | |
322 | } | |
323 | ||
4db2ff0d | 324 | void jsonw_int_field(json_writer_t *self, const char *prop, int num) |
fcc16c22 SH |
325 | { |
326 | jsonw_name(self, prop); | |
327 | jsonw_int(self, num); | |
328 | } | |
329 | ||
4db2ff0d THJ |
330 | void jsonw_s64_field(json_writer_t *self, const char *prop, int64_t num) |
331 | { | |
332 | jsonw_name(self, prop); | |
333 | jsonw_s64(self, num); | |
334 | } | |
335 | ||
fcc16c22 SH |
336 | void jsonw_null_field(json_writer_t *self, const char *prop) |
337 | { | |
338 | jsonw_name(self, prop); | |
339 | jsonw_null(self); | |
340 | } | |
fcc16c22 SH |
341 | |
342 | #ifdef TEST | |
343 | int main(int argc, char **argv) | |
344 | { | |
345 | json_writer_t *wr = jsonw_new(stdout); | |
346 | ||
d721a145 | 347 | jsonw_start_object(wr); |
fcc16c22 SH |
348 | jsonw_pretty(wr, true); |
349 | jsonw_name(wr, "Vyatta"); | |
350 | jsonw_start_object(wr); | |
351 | jsonw_string_field(wr, "url", "http://vyatta.com"); | |
352 | jsonw_uint_field(wr, "downloads", 2000000ul); | |
353 | jsonw_float_field(wr, "stock", 8.16); | |
354 | ||
355 | jsonw_name(wr, "ARGV"); | |
356 | jsonw_start_array(wr); | |
357 | while (--argc) | |
358 | jsonw_string(wr, *++argv); | |
359 | jsonw_end_array(wr); | |
360 | ||
361 | jsonw_name(wr, "empty"); | |
362 | jsonw_start_array(wr); | |
363 | jsonw_end_array(wr); | |
364 | ||
365 | jsonw_name(wr, "NIL"); | |
366 | jsonw_start_object(wr); | |
367 | jsonw_end_object(wr); | |
368 | ||
369 | jsonw_null_field(wr, "my_null"); | |
370 | ||
371 | jsonw_name(wr, "special chars"); | |
372 | jsonw_start_array(wr); | |
373 | jsonw_string_field(wr, "slash", "/"); | |
374 | jsonw_string_field(wr, "newline", "\n"); | |
375 | jsonw_string_field(wr, "tab", "\t"); | |
376 | jsonw_string_field(wr, "ff", "\f"); | |
377 | jsonw_string_field(wr, "quote", "\""); | |
378 | jsonw_string_field(wr, "tick", "\'"); | |
379 | jsonw_string_field(wr, "backslash", "\\"); | |
380 | jsonw_end_array(wr); | |
381 | ||
382 | jsonw_end_object(wr); | |
383 | ||
d721a145 | 384 | jsonw_end_object(wr); |
fcc16c22 SH |
385 | jsonw_destroy(&wr); |
386 | return 0; | |
387 | } | |
388 | ||
389 | #endif |