2 * Copyright (c) 2009, 2010 Nicira Networks.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
29 #include "dynamic-string.h"
35 /* The type of a JSON token. */
36 enum json_token_type {
42 T_NAME_SEPARATOR = ':',
43 T_VALUE_SEPARATOR = ',',
44 T_FALSE = UCHAR_MAX + 1,
54 * RFC 4627 doesn't define a lexical structure for JSON but I believe this to
55 * be compliant with the standard.
58 enum json_token_type type;
61 long long int integer;
67 JSON_LEX_START, /* Not inside a token. */
68 JSON_LEX_NUMBER, /* Reading a number. */
69 JSON_LEX_KEYWORD, /* Reading a keyword. */
70 JSON_LEX_STRING, /* Reading a quoted string. */
71 JSON_LEX_ESCAPE /* In a quoted string just after a "\". */
74 enum json_parse_state {
75 JSON_PARSE_START, /* Beginning of input. */
76 JSON_PARSE_END, /* End of input. */
79 JSON_PARSE_OBJECT_INIT, /* Expecting '}' or an object name. */
80 JSON_PARSE_OBJECT_NAME, /* Expecting an object name. */
81 JSON_PARSE_OBJECT_COLON, /* Expecting ':'. */
82 JSON_PARSE_OBJECT_VALUE, /* Expecting an object value. */
83 JSON_PARSE_OBJECT_NEXT, /* Expecting ',' or '}'. */
86 JSON_PARSE_ARRAY_INIT, /* Expecting ']' or a value. */
87 JSON_PARSE_ARRAY_VALUE, /* Expecting a value. */
88 JSON_PARSE_ARRAY_NEXT /* Expecting ',' or ']'. */
91 struct json_parser_node {
99 /* Lexical analysis. */
100 enum json_lex_state lex_state;
101 struct ds buffer; /* Buffer for accumulating token text. */
107 enum json_parse_state parse_state;
108 #define JSON_MAX_HEIGHT 1000
109 struct json_parser_node *stack;
110 size_t height, allocated_height;
115 char *error; /* Error message, if any, null if none yet. */
118 static struct json *json_create(enum json_type type);
119 static void json_parser_input(struct json_parser *, struct json_token *);
121 static void json_error(struct json_parser *p, const char *format, ...)
125 json_type_to_string(enum json_type type)
156 /* Functions for manipulating struct json. */
159 json_null_create(void)
161 return json_create(JSON_NULL);
165 json_boolean_create(bool b)
167 return json_create(b ? JSON_TRUE : JSON_FALSE);
171 json_string_create_nocopy(char *s)
173 struct json *json = json_create(JSON_STRING);
179 json_string_create(const char *s)
181 return json_string_create_nocopy(xstrdup(s));
185 json_array_create_empty(void)
187 struct json *json = json_create(JSON_ARRAY);
188 json->u.array.elems = NULL;
190 json->u.array.n_allocated = 0;
195 json_array_add(struct json *array_, struct json *element)
197 struct json_array *array = json_array(array_);
198 if (array->n >= array->n_allocated) {
199 array->elems = x2nrealloc(array->elems, &array->n_allocated,
200 sizeof *array->elems);
202 array->elems[array->n++] = element;
206 json_array_trim(struct json *array_)
208 struct json_array *array = json_array(array_);
209 if (array->n < array->n_allocated){
210 array->n_allocated = array->n;
211 array->elems = xrealloc(array->elems, array->n * sizeof *array->elems);
216 json_array_create(struct json **elements, size_t n)
218 struct json *json = json_create(JSON_ARRAY);
219 json->u.array.elems = elements;
221 json->u.array.n_allocated = n;
226 json_array_create_1(struct json *elem0)
228 struct json **elems = xmalloc(sizeof *elems);
230 return json_array_create(elems, 1);
234 json_array_create_2(struct json *elem0, struct json *elem1)
236 struct json **elems = xmalloc(2 * sizeof *elems);
239 return json_array_create(elems, 2);
243 json_array_create_3(struct json *elem0, struct json *elem1, struct json *elem2)
245 struct json **elems = xmalloc(3 * sizeof *elems);
249 return json_array_create(elems, 3);
253 json_object_create(void)
255 struct json *json = json_create(JSON_OBJECT);
256 json->u.object = xmalloc(sizeof *json->u.object);
257 shash_init(json->u.object);
262 json_integer_create(long long int integer)
264 struct json *json = json_create(JSON_INTEGER);
265 json->u.integer = integer;
270 json_real_create(double real)
272 struct json *json = json_create(JSON_REAL);
278 json_object_put(struct json *json, const char *name, struct json *value)
280 json_destroy(shash_replace(json->u.object, name, value));
284 json_object_put_string(struct json *json, const char *name, const char *value)
286 json_object_put(json, name, json_string_create(value));
290 json_string(const struct json *json)
292 assert(json->type == JSON_STRING);
293 return json->u.string;
297 json_array(const struct json *json)
299 assert(json->type == JSON_ARRAY);
300 return (struct json_array *) &json->u.array;
304 json_object(const struct json *json)
306 assert(json->type == JSON_OBJECT);
307 return (struct shash *) json->u.object;
311 json_boolean(const struct json *json)
313 assert(json->type == JSON_TRUE || json->type == JSON_FALSE);
314 return json->type == JSON_TRUE;
318 json_real(const struct json *json)
320 assert(json->type == JSON_REAL || json->type == JSON_INTEGER);
321 return json->type == JSON_REAL ? json->u.real : json->u.integer;
325 json_integer(const struct json *json)
327 assert(json->type == JSON_INTEGER);
328 return json->u.integer;
331 static void json_destroy_object(struct shash *object);
332 static void json_destroy_array(struct json_array *array);
334 /* Frees 'json' and everything it points to, recursively. */
336 json_destroy(struct json *json)
339 switch (json->type) {
341 json_destroy_object(json->u.object);
345 json_destroy_array(&json->u.array);
349 free(json->u.string);
367 json_destroy_object(struct shash *object)
369 struct shash_node *node, *next;
371 SHASH_FOR_EACH_SAFE (node, next, object) {
372 struct json *value = node->data;
375 shash_delete(object, node);
377 shash_destroy(object);
382 json_destroy_array(struct json_array *array)
386 for (i = 0; i < array->n; i++) {
387 json_destroy(array->elems[i]);
392 static struct json *json_clone_object(const struct shash *object);
393 static struct json *json_clone_array(const struct json_array *array);
395 /* Returns a deep copy of 'json'. */
397 json_clone(const struct json *json)
399 switch (json->type) {
401 return json_clone_object(json->u.object);
404 return json_clone_array(&json->u.array);
407 return json_string_create(json->u.string);
412 return json_create(json->type);
415 return json_integer_create(json->u.integer);
418 return json_real_create(json->u.real);
427 json_clone_object(const struct shash *object)
429 struct shash_node *node;
432 json = json_object_create();
433 SHASH_FOR_EACH (node, object) {
434 struct json *value = node->data;
435 json_object_put(json, node->name, json_clone(value));
441 json_clone_array(const struct json_array *array)
446 elems = xmalloc(array->n * sizeof *elems);
447 for (i = 0; i < array->n; i++) {
448 elems[i] = json_clone(array->elems[i]);
450 return json_array_create(elems, array->n);
454 json_hash_object(const struct shash *object, size_t basis)
456 const struct shash_node **nodes;
459 nodes = shash_sort(object);
460 n = shash_count(object);
461 for (i = 0; i < n; i++) {
462 const struct shash_node *node = nodes[i];
463 basis = hash_string(node->name, basis);
464 basis = json_hash(node->data, basis);
470 json_hash_array(const struct json_array *array, size_t basis)
474 basis = hash_int(array->n, basis);
475 for (i = 0; i < array->n; i++) {
476 basis = json_hash(array->elems[i], basis);
482 json_hash(const struct json *json, size_t basis)
484 switch (json->type) {
486 return json_hash_object(json->u.object, basis);
489 return json_hash_array(&json->u.array, basis);
492 return hash_string(json->u.string, basis);
497 return hash_int(json->type << 8, basis);
500 return hash_int(json->u.integer, basis);
503 return hash_double(json->u.real, basis);
512 json_equal_object(const struct shash *a, const struct shash *b)
514 struct shash_node *a_node;
516 if (shash_count(a) != shash_count(b)) {
520 SHASH_FOR_EACH (a_node, a) {
521 struct shash_node *b_node = shash_find(b, a_node->name);
522 if (!b_node || !json_equal(a_node->data, b_node->data)) {
531 json_equal_array(const struct json_array *a, const struct json_array *b)
539 for (i = 0; i < a->n; i++) {
540 if (!json_equal(a->elems[i], b->elems[i])) {
549 json_equal(const struct json *a, const struct json *b)
551 if (a->type != b->type) {
557 return json_equal_object(a->u.object, b->u.object);
560 return json_equal_array(&a->u.array, &b->u.array);
563 return !strcmp(a->u.string, b->u.string);
571 return a->u.integer == b->u.integer;
574 return a->u.real == b->u.real;
582 /* Lexical analysis. */
585 json_lex_keyword(struct json_parser *p)
587 struct json_token token;
590 s = ds_cstr(&p->buffer);
591 if (!strcmp(s, "false")) {
592 token.type = T_FALSE;
593 } else if (!strcmp(s, "true")) {
595 } else if (!strcmp(s, "null")) {
598 json_error(p, "invalid keyword '%s'", s);
601 json_parser_input(p, &token);
605 json_lex_number(struct json_parser *p)
607 const char *cp = ds_cstr(&p->buffer);
608 unsigned long long int significand = 0;
609 struct json_token token;
610 bool imprecise = false;
611 bool negative = false;
614 /* Leading minus sign. */
620 /* At least one integer digit, but 0 may not be used as a leading digit for
621 * a longer number. */
626 json_error(p, "leading zeros not allowed");
629 } else if (isdigit(*cp)) {
631 if (significand <= ULLONG_MAX / 10) {
632 significand = significand * 10 + (*cp - '0');
640 } while (isdigit(*cp));
642 json_error(p, "'-' must be followed by digit");
646 /* Optional fraction. */
650 json_error(p, "decimal point must be followed by digit");
654 if (significand <= ULLONG_MAX / 10) {
655 significand = significand * 10 + (*cp - '0');
657 } else if (*cp != '0') {
661 } while (isdigit(*cp));
664 /* Optional exponent. */
665 if (*cp == 'e' || *cp == 'E') {
666 bool negative_exponent = false;
672 } else if (*cp == '-') {
673 negative_exponent = true;
678 json_error(p, "exponent must contain at least one digit");
684 if (exponent >= INT_MAX / 10) {
685 json_error(p, "exponent outside valid range");
688 exponent = exponent * 10 + (*cp - '0');
690 } while (isdigit(*cp));
692 if (negative_exponent) {
700 json_error(p, "syntax error in number");
704 /* Figure out number.
706 * We suppress negative zeros as a matter of policy. */
708 token.type = T_INTEGER;
710 json_parser_input(p, &token);
715 while (pow10 > 0 && significand < ULLONG_MAX / 10) {
719 while (pow10 < 0 && significand % 10 == 0) {
724 && significand <= (negative
725 ? (unsigned long long int) LLONG_MAX + 1
727 token.type = T_INTEGER;
728 token.u.integer = negative ? -significand : significand;
729 json_parser_input(p, &token);
735 if (!str_to_double(ds_cstr(&p->buffer), &token.u.real)) {
736 json_error(p, "number outside valid range");
739 /* Suppress negative zero. */
740 if (token.u.real == 0) {
743 json_parser_input(p, &token);
747 json_lex_4hex(const char *cp, const char *end, int *valuep)
752 return "quoted string ends within \\u escape";
756 for (i = 0; i < 4; i++) {
757 unsigned char c = *cp++;
759 return "malformed \\u escape";
761 value = (value << 4) | hexit_value(c);
764 return "null bytes not supported in quoted strings";
771 json_lex_unicode(const char *cp, const char *end, struct ds *out)
776 error = json_lex_4hex(cp, end, &c0);
779 ds_put_cstr(out, error);
783 if (!uc_is_leading_surrogate(c0)) {
784 ds_put_utf8(out, c0);
788 if (cp + 2 > end || *cp++ != '\\' || *cp++ != 'u') {
790 ds_put_cstr(out, "malformed escaped surrogate pair");
794 error = json_lex_4hex(cp, end, &c1);
797 ds_put_cstr(out, error);
801 if (!uc_is_trailing_surrogate(c1)) {
803 ds_put_cstr(out, "second half of escaped surrogate pair is not "
804 "trailing surrogate");
808 ds_put_utf8(out, utf16_decode_surrogate_pair(c0, c1));
813 json_string_unescape(const char *in, size_t in_len, char **outp)
815 const char *end = in + in_len;
820 ds_reserve(&out, in_len);
821 if (in_len > 0 && in[in_len - 1] == '\\') {
822 ds_put_cstr(&out, "quoted string may not end with backslash");
828 ds_put_cstr(&out, "quoted string may not include unescaped \"");
832 ds_put_char(&out, *in++);
838 case '"': case '\\': case '/':
839 ds_put_char(&out, in[-1]);
843 ds_put_char(&out, '\b');
847 ds_put_char(&out, '\f');
851 ds_put_char(&out, '\n');
855 ds_put_char(&out, '\r');
859 ds_put_char(&out, '\t');
863 in = json_lex_unicode(in, end, &out);
871 ds_put_format(&out, "bad escape \\%c", in[-1]);
878 *outp = ds_cstr(&out);
883 json_parser_input_string(struct json_parser *p, const char *s)
885 struct json_token token;
887 token.type = T_STRING;
889 json_parser_input(p, &token);
893 json_lex_string(struct json_parser *p)
895 const char *raw = ds_cstr(&p->buffer);
896 if (!strchr(raw, '\\')) {
897 json_parser_input_string(p, raw);
901 if (json_string_unescape(raw, strlen(raw), &cooked)) {
902 json_parser_input_string(p, cooked);
904 json_error(p, "%s", cooked);
912 json_lex_input(struct json_parser *p, unsigned char c)
914 struct json_token token;
918 p->column_number = 0;
924 switch (p->lex_state) {
927 case ' ': case '\t': case '\n': case '\r':
931 case 'a': case 'b': case 'c': case 'd': case 'e':
932 case 'f': case 'g': case 'h': case 'i': case 'j':
933 case 'k': case 'l': case 'm': case 'n': case 'o':
934 case 'p': case 'q': case 'r': case 's': case 't':
935 case 'u': case 'v': case 'w': case 'x': case 'y':
937 p->lex_state = JSON_LEX_KEYWORD;
940 case '[': case '{': case ']': case '}': case ':': case ',':
942 json_parser_input(p, &token);
946 case '0': case '1': case '2': case '3': case '4':
947 case '5': case '6': case '7': case '8': case '9':
948 p->lex_state = JSON_LEX_NUMBER;
952 p->lex_state = JSON_LEX_STRING;
957 json_error(p, "invalid character '%c'", c);
959 json_error(p, "invalid character U+%04x", c);
965 case JSON_LEX_KEYWORD:
966 if (!isalpha((unsigned char) c)) {
972 case JSON_LEX_NUMBER:
973 if (!strchr(".0123456789eE-+", c)) {
979 case JSON_LEX_STRING:
981 p->lex_state = JSON_LEX_ESCAPE;
982 } else if (c == '"') {
985 } else if (c < 0x20) {
986 json_error(p, "U+%04X must be escaped in quoted string", c);
991 case JSON_LEX_ESCAPE:
992 p->lex_state = JSON_LEX_STRING;
998 ds_put_char(&p->buffer, c);
1004 /* Parses 'string' as a JSON object or array and returns a newly allocated
1005 * 'struct json'. The caller must free the returned structure with
1006 * json_destroy() when it is no longer needed.
1008 * 'string' must be encoded in UTF-8.
1010 * If 'string' is valid JSON, then the returned 'struct json' will be either an
1011 * object (JSON_OBJECT) or an array (JSON_ARRAY).
1013 * If 'string' is not valid JSON, then the returned 'struct json' will be a
1014 * string (JSON_STRING) that describes the particular error encountered during
1015 * parsing. (This is an acceptable means of error reporting because at its top
1016 * level JSON must be either an object or an array; a bare string is not
1019 json_from_string(const char *string)
1021 struct json_parser *p = json_parser_create(JSPF_TRAILER);
1022 json_parser_feed(p, string, strlen(string));
1023 return json_parser_finish(p);
1026 /* Reads the file named 'file_name', parses its contents as a JSON object or
1027 * array, and returns a newly allocated 'struct json'. The caller must free
1028 * the returned structure with json_destroy() when it is no longer needed.
1030 * The file must be encoded in UTF-8.
1032 * See json_from_string() for return value semantics.
1035 json_from_file(const char *file_name)
1040 stream = fopen(file_name, "r");
1042 return json_string_create_nocopy(
1043 xasprintf("error opening \"%s\": %s", file_name, strerror(errno)));
1045 json = json_from_stream(stream);
1051 /* Parses the contents of 'stream' as a JSON object or array, and returns a
1052 * newly allocated 'struct json'. The caller must free the returned structure
1053 * with json_destroy() when it is no longer needed.
1055 * The file must be encoded in UTF-8.
1057 * See json_from_string() for return value semantics.
1060 json_from_stream(FILE *stream)
1062 struct json_parser *p;
1065 p = json_parser_create(JSPF_TRAILER);
1067 char buffer[BUFSIZ];
1070 n = fread(buffer, 1, sizeof buffer, stream);
1071 if (!n || json_parser_feed(p, buffer, n) != n) {
1075 json = json_parser_finish(p);
1077 if (ferror(stream)) {
1079 json = json_string_create_nocopy(
1080 xasprintf("error reading JSON stream: %s", strerror(errno)));
1086 struct json_parser *
1087 json_parser_create(int flags)
1089 struct json_parser *p = xzalloc(sizeof *p);
1095 json_parser_feed(struct json_parser *p, const char *input, size_t n)
1098 for (i = 0; !p->done && i < n; ) {
1099 if (json_lex_input(p, input[i])) {
1107 json_parser_is_done(const struct json_parser *p)
1113 json_parser_finish(struct json_parser *p)
1117 switch (p->lex_state) {
1118 case JSON_LEX_START:
1121 case JSON_LEX_STRING:
1122 case JSON_LEX_ESCAPE:
1123 json_error(p, "unexpected end of input in quoted string");
1126 case JSON_LEX_NUMBER:
1127 case JSON_LEX_KEYWORD:
1128 json_lex_input(p, ' ');
1132 if (p->parse_state == JSON_PARSE_START) {
1133 json_error(p, "empty input stream");
1134 } else if (p->parse_state != JSON_PARSE_END) {
1135 json_error(p, "unexpected end of input");
1139 assert(p->height == 1);
1140 assert(p->stack[0].json != NULL);
1141 json = p->stack[--p->height].json;
1143 json = json_string_create_nocopy(p->error);
1147 json_parser_abort(p);
1153 json_parser_abort(struct json_parser *p)
1156 ds_destroy(&p->buffer);
1158 json_destroy(p->stack[0].json);
1161 free(p->member_name);
1167 static struct json_parser_node *
1168 json_parser_top(struct json_parser *p)
1170 return &p->stack[p->height - 1];
1174 json_parser_put_value(struct json_parser *p, struct json *value)
1176 struct json_parser_node *node = json_parser_top(p);
1177 if (node->json->type == JSON_OBJECT) {
1178 json_object_put(node->json, p->member_name, value);
1179 free(p->member_name);
1180 p->member_name = NULL;
1181 } else if (node->json->type == JSON_ARRAY) {
1182 json_array_add(node->json, value);
1189 json_parser_push(struct json_parser *p,
1190 struct json *new_json, enum json_parse_state new_state)
1192 if (p->height < JSON_MAX_HEIGHT) {
1193 struct json_parser_node *node;
1195 if (p->height >= p->allocated_height) {
1196 p->stack = x2nrealloc(p->stack, &p->allocated_height,
1200 if (p->height > 0) {
1201 json_parser_put_value(p, new_json);
1204 node = &p->stack[p->height++];
1205 node->json = new_json;
1206 p->parse_state = new_state;
1208 json_destroy(new_json);
1209 json_error(p, "input exceeds maximum nesting depth %d",
1215 json_parser_push_object(struct json_parser *p)
1217 json_parser_push(p, json_object_create(), JSON_PARSE_OBJECT_INIT);
1221 json_parser_push_array(struct json_parser *p)
1223 json_parser_push(p, json_array_create_empty(), JSON_PARSE_ARRAY_INIT);
1227 json_parse_value(struct json_parser *p, struct json_token *token,
1228 enum json_parse_state next_state)
1232 switch (token->type) {
1234 value = json_boolean_create(false);
1238 value = json_null_create();
1242 value = json_boolean_create(true);
1246 json_parser_push_object(p);
1250 json_parser_push_array(p);
1254 value = json_integer_create(token->u.integer);
1258 value = json_real_create(token->u.real);
1262 value = json_string_create(token->u.string);
1271 json_error(p, "syntax error expecting value");
1275 json_parser_put_value(p, value);
1276 p->parse_state = next_state;
1280 json_parser_pop(struct json_parser *p)
1282 struct json_parser_node *node;
1284 /* Conserve memory. */
1285 node = json_parser_top(p);
1286 if (node->json->type == JSON_ARRAY) {
1287 json_array_trim(node->json);
1290 /* Pop off the top-of-stack. */
1291 if (p->height == 1) {
1292 p->parse_state = JSON_PARSE_END;
1293 if (!(p->flags & JSPF_TRAILER)) {
1298 node = json_parser_top(p);
1299 if (node->json->type == JSON_ARRAY) {
1300 p->parse_state = JSON_PARSE_ARRAY_NEXT;
1301 } else if (node->json->type == JSON_OBJECT) {
1302 p->parse_state = JSON_PARSE_OBJECT_NEXT;
1310 json_parser_input(struct json_parser *p, struct json_token *token)
1312 switch (p->parse_state) {
1313 case JSON_PARSE_START:
1314 if (token->type == '{') {
1315 json_parser_push_object(p);
1316 } else if (token->type == '[') {
1317 json_parser_push_array(p);
1319 json_error(p, "syntax error at beginning of input");
1323 case JSON_PARSE_END:
1324 json_error(p, "trailing garbage at end of input");
1327 case JSON_PARSE_OBJECT_INIT:
1328 if (token->type == '}') {
1333 case JSON_PARSE_OBJECT_NAME:
1334 if (token->type == T_STRING) {
1335 p->member_name = xstrdup(token->u.string);
1336 p->parse_state = JSON_PARSE_OBJECT_COLON;
1338 json_error(p, "syntax error parsing object expecting string");
1342 case JSON_PARSE_OBJECT_COLON:
1343 if (token->type == ':') {
1344 p->parse_state = JSON_PARSE_OBJECT_VALUE;
1346 json_error(p, "syntax error parsing object expecting ':'");
1350 case JSON_PARSE_OBJECT_VALUE:
1351 json_parse_value(p, token, JSON_PARSE_OBJECT_NEXT);
1354 case JSON_PARSE_OBJECT_NEXT:
1355 if (token->type == ',') {
1356 p->parse_state = JSON_PARSE_OBJECT_NAME;
1357 } else if (token->type == '}') {
1360 json_error(p, "syntax error expecting '}' or ','");
1364 case JSON_PARSE_ARRAY_INIT:
1365 if (token->type == ']') {
1370 case JSON_PARSE_ARRAY_VALUE:
1371 json_parse_value(p, token, JSON_PARSE_ARRAY_NEXT);
1374 case JSON_PARSE_ARRAY_NEXT:
1375 if (token->type == ',') {
1376 p->parse_state = JSON_PARSE_ARRAY_VALUE;
1377 } else if (token->type == ']') {
1380 json_error(p, "syntax error expecting ']' or ','");
1388 p->lex_state = JSON_LEX_START;
1389 ds_clear(&p->buffer);
1392 static struct json *
1393 json_create(enum json_type type)
1395 struct json *json = xmalloc(sizeof *json);
1401 json_error(struct json_parser *p, const char *format, ...)
1408 ds_put_format(&msg, "line %d, column %d, byte %d: ",
1409 p->line_number, p->column_number, p->byte_number);
1410 va_start(args, format);
1411 ds_put_format_valist(&msg, format, args);
1414 p->error = ds_steal_cstr(&msg);
1420 #define SPACES_PER_LEVEL 2
1422 struct json_serializer {
1428 static void json_serialize(const struct json *, struct json_serializer *);
1429 static void json_serialize_object(const struct shash *object,
1430 struct json_serializer *);
1431 static void json_serialize_array(const struct json_array *,
1432 struct json_serializer *);
1433 static void json_serialize_string(const char *, struct ds *);
1435 /* Converts 'json' to a string in JSON format, encoded in UTF-8, and returns
1436 * that string. The caller is responsible for freeing the returned string,
1437 * with free(), when it is no longer needed.
1439 * If 'flags' contains JSSF_PRETTY, the output is pretty-printed with each
1440 * nesting level introducing an additional indentation. Otherwise, the
1441 * returned string does not contain any new-line characters.
1443 * If 'flags' contains JSSF_SORT, members of objects in the output are sorted
1444 * in bytewise lexicographic order for reproducibility. Otherwise, members of
1445 * objects are output in an indeterminate order.
1447 * The returned string is valid JSON only if 'json' represents an array or an
1448 * object, since a bare literal does not satisfy the JSON grammar. */
1450 json_to_string(const struct json *json, int flags)
1455 json_to_ds(json, flags, &ds);
1456 return ds_steal_cstr(&ds);
1459 /* Same as json_to_string(), but the output is appended to 'ds'. */
1461 json_to_ds(const struct json *json, int flags, struct ds *ds)
1463 struct json_serializer s;
1468 json_serialize(json, &s);
1472 json_serialize(const struct json *json, struct json_serializer *s)
1474 struct ds *ds = s->ds;
1476 switch (json->type) {
1478 ds_put_cstr(ds, "null");
1482 ds_put_cstr(ds, "false");
1486 ds_put_cstr(ds, "true");
1490 json_serialize_object(json->u.object, s);
1494 json_serialize_array(&json->u.array, s);
1498 ds_put_format(ds, "%lld", json->u.integer);
1502 ds_put_format(ds, "%.*g", DBL_DIG, json->u.real);
1506 json_serialize_string(json->u.string, ds);
1516 indent_line(struct json_serializer *s)
1518 if (s->flags & JSSF_PRETTY) {
1519 ds_put_char(s->ds, '\n');
1520 ds_put_char_multiple(s->ds, ' ', SPACES_PER_LEVEL * s->depth);
1525 json_serialize_object_member(size_t i, const struct shash_node *node,
1526 struct json_serializer *s)
1528 struct ds *ds = s->ds;
1531 ds_put_char(ds, ',');
1535 json_serialize_string(node->name, ds);
1536 ds_put_char(ds, ':');
1537 if (s->flags & JSSF_PRETTY) {
1538 ds_put_char(ds, ' ');
1540 json_serialize(node->data, s);
1544 json_serialize_object(const struct shash *object, struct json_serializer *s)
1546 struct ds *ds = s->ds;
1548 ds_put_char(ds, '{');
1553 if (s->flags & JSSF_SORT) {
1554 const struct shash_node **nodes;
1557 nodes = shash_sort(object);
1558 n = shash_count(object);
1559 for (i = 0; i < n; i++) {
1560 json_serialize_object_member(i, nodes[i], s);
1564 struct shash_node *node;
1568 SHASH_FOR_EACH (node, object) {
1569 json_serialize_object_member(i++, node, s);
1573 ds_put_char(ds, '}');
1578 json_serialize_array(const struct json_array *array, struct json_serializer *s)
1580 struct ds *ds = s->ds;
1583 ds_put_char(ds, '[');
1589 for (i = 0; i < array->n; i++) {
1591 ds_put_char(ds, ',');
1594 json_serialize(array->elems[i], s);
1599 ds_put_char(ds, ']');
1603 json_serialize_string(const char *string, struct ds *ds)
1607 ds_put_char(ds, '"');
1608 while ((c = *string++) != '\0') {
1611 ds_put_cstr(ds, "\\\"");
1615 ds_put_cstr(ds, "\\\\");
1619 ds_put_cstr(ds, "\\b");
1623 ds_put_cstr(ds, "\\f");
1627 ds_put_cstr(ds, "\\n");
1631 ds_put_cstr(ds, "\\r");
1635 ds_put_cstr(ds, "\\t");
1642 ds_put_format(ds, "\\u%04x", c);
1647 ds_put_char(ds, '"');