qemu-error: add {error, warn}_report_once_cond
[qemu.git] / qobject / json-parser.c
blob5a840dfd860735d3f7a2bea8b91cfb2dbc01e6d9
1 /*
2 * JSON Parser
4 * Copyright IBM, Corp. 2009
6 * Authors:
7 * Anthony Liguori <aliguori@us.ibm.com>
9 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
10 * See the COPYING.LIB file in the top-level directory.
14 #include "qemu/osdep.h"
15 #include "qemu/cutils.h"
16 #include "qemu/unicode.h"
17 #include "qapi/error.h"
18 #include "qemu-common.h"
19 #include "qapi/qmp/qbool.h"
20 #include "qapi/qmp/qdict.h"
21 #include "qapi/qmp/qlist.h"
22 #include "qapi/qmp/qnull.h"
23 #include "qapi/qmp/qnum.h"
24 #include "qapi/qmp/qstring.h"
25 #include "json-parser-int.h"
27 struct JSONToken {
28 JSONTokenType type;
29 int x;
30 int y;
31 char str[];
34 typedef struct JSONParserContext
36 Error *err;
37 JSONToken *current;
38 GQueue *buf;
39 va_list *ap;
40 } JSONParserContext;
42 #define BUG_ON(cond) assert(!(cond))
44 /**
45 * TODO
47 * 0) make errors meaningful again
48 * 1) add geometry information to tokens
49 * 3) should we return a parsed size?
50 * 4) deal with premature EOI
53 static QObject *parse_value(JSONParserContext *ctxt);
55 /**
56 * Error handler
58 static void GCC_FMT_ATTR(3, 4) parse_error(JSONParserContext *ctxt,
59 JSONToken *token, const char *msg, ...)
61 va_list ap;
62 char message[1024];
64 if (ctxt->err) {
65 return;
67 va_start(ap, msg);
68 vsnprintf(message, sizeof(message), msg, ap);
69 va_end(ap);
70 error_setg(&ctxt->err, "JSON parse error, %s", message);
73 static int cvt4hex(const char *s)
75 int cp, i;
77 cp = 0;
78 for (i = 0; i < 4; i++) {
79 if (!qemu_isxdigit(s[i])) {
80 return -1;
82 cp <<= 4;
83 if (s[i] >= '0' && s[i] <= '9') {
84 cp |= s[i] - '0';
85 } else if (s[i] >= 'a' && s[i] <= 'f') {
86 cp |= 10 + s[i] - 'a';
87 } else if (s[i] >= 'A' && s[i] <= 'F') {
88 cp |= 10 + s[i] - 'A';
89 } else {
90 return -1;
93 return cp;
96 /**
97 * parse_string(): Parse a JSON string
99 * From RFC 8259 "The JavaScript Object Notation (JSON) Data
100 * Interchange Format":
102 * char = unescaped /
103 * escape (
104 * %x22 / ; " quotation mark U+0022
105 * %x5C / ; \ reverse solidus U+005C
106 * %x2F / ; / solidus U+002F
107 * %x62 / ; b backspace U+0008
108 * %x66 / ; f form feed U+000C
109 * %x6E / ; n line feed U+000A
110 * %x72 / ; r carriage return U+000D
111 * %x74 / ; t tab U+0009
112 * %x75 4HEXDIG ) ; uXXXX U+XXXX
113 * escape = %x5C ; \
114 * quotation-mark = %x22 ; "
115 * unescaped = %x20-21 / %x23-5B / %x5D-10FFFF
117 * Extensions over RFC 8259:
118 * - Extra escape sequence in strings:
119 * 0x27 (apostrophe) is recognized after escape, too
120 * - Single-quoted strings:
121 * Like double-quoted strings, except they're delimited by %x27
122 * (apostrophe) instead of %x22 (quotation mark), and can't contain
123 * unescaped apostrophe, but can contain unescaped quotation mark.
125 * Note:
126 * - Encoding is modified UTF-8.
127 * - Invalid Unicode characters are rejected.
128 * - Control characters \x00..\x1F are rejected by the lexer.
130 static QString *parse_string(JSONParserContext *ctxt, JSONToken *token)
132 const char *ptr = token->str;
133 QString *str;
134 char quote;
135 const char *beg;
136 int cp, trailing;
137 char *end;
138 ssize_t len;
139 char utf8_buf[5];
141 assert(*ptr == '"' || *ptr == '\'');
142 quote = *ptr++;
143 str = qstring_new();
145 while (*ptr != quote) {
146 assert(*ptr);
147 switch (*ptr) {
148 case '\\':
149 beg = ptr++;
150 switch (*ptr++) {
151 case '"':
152 qstring_append_chr(str, '"');
153 break;
154 case '\'':
155 qstring_append_chr(str, '\'');
156 break;
157 case '\\':
158 qstring_append_chr(str, '\\');
159 break;
160 case '/':
161 qstring_append_chr(str, '/');
162 break;
163 case 'b':
164 qstring_append_chr(str, '\b');
165 break;
166 case 'f':
167 qstring_append_chr(str, '\f');
168 break;
169 case 'n':
170 qstring_append_chr(str, '\n');
171 break;
172 case 'r':
173 qstring_append_chr(str, '\r');
174 break;
175 case 't':
176 qstring_append_chr(str, '\t');
177 break;
178 case 'u':
179 cp = cvt4hex(ptr);
180 ptr += 4;
182 /* handle surrogate pairs */
183 if (cp >= 0xD800 && cp <= 0xDBFF
184 && ptr[0] == '\\' && ptr[1] == 'u') {
185 /* leading surrogate followed by \u */
186 cp = 0x10000 + ((cp & 0x3FF) << 10);
187 trailing = cvt4hex(ptr + 2);
188 if (trailing >= 0xDC00 && trailing <= 0xDFFF) {
189 /* followed by trailing surrogate */
190 cp |= trailing & 0x3FF;
191 ptr += 6;
192 } else {
193 cp = -1; /* invalid */
197 if (mod_utf8_encode(utf8_buf, sizeof(utf8_buf), cp) < 0) {
198 parse_error(ctxt, token,
199 "%.*s is not a valid Unicode character",
200 (int)(ptr - beg), beg);
201 goto out;
203 qstring_append(str, utf8_buf);
204 break;
205 default:
206 parse_error(ctxt, token, "invalid escape sequence in string");
207 goto out;
209 break;
210 case '%':
211 if (ctxt->ap && ptr[1] != '%') {
212 parse_error(ctxt, token, "can't interpolate into string");
213 goto out;
215 ptr++;
216 /* fall through */
217 default:
218 cp = mod_utf8_codepoint(ptr, 6, &end);
219 if (cp < 0) {
220 parse_error(ctxt, token, "invalid UTF-8 sequence in string");
221 goto out;
223 ptr = end;
224 len = mod_utf8_encode(utf8_buf, sizeof(utf8_buf), cp);
225 assert(len >= 0);
226 qstring_append(str, utf8_buf);
230 return str;
232 out:
233 qobject_unref(str);
234 return NULL;
237 /* Note: the token object returned by parser_context_peek_token or
238 * parser_context_pop_token is deleted as soon as parser_context_pop_token
239 * is called again.
241 static JSONToken *parser_context_pop_token(JSONParserContext *ctxt)
243 g_free(ctxt->current);
244 ctxt->current = g_queue_pop_head(ctxt->buf);
245 return ctxt->current;
248 static JSONToken *parser_context_peek_token(JSONParserContext *ctxt)
250 return g_queue_peek_head(ctxt->buf);
254 * Parsing rules
256 static int parse_pair(JSONParserContext *ctxt, QDict *dict)
258 QObject *value;
259 QString *key = NULL;
260 JSONToken *peek, *token;
262 peek = parser_context_peek_token(ctxt);
263 if (peek == NULL) {
264 parse_error(ctxt, NULL, "premature EOI");
265 goto out;
268 key = qobject_to(QString, parse_value(ctxt));
269 if (!key) {
270 parse_error(ctxt, peek, "key is not a string in object");
271 goto out;
274 token = parser_context_pop_token(ctxt);
275 if (token == NULL) {
276 parse_error(ctxt, NULL, "premature EOI");
277 goto out;
280 if (token->type != JSON_COLON) {
281 parse_error(ctxt, token, "missing : in object pair");
282 goto out;
285 value = parse_value(ctxt);
286 if (value == NULL) {
287 parse_error(ctxt, token, "Missing value in dict");
288 goto out;
291 qdict_put_obj(dict, qstring_get_str(key), value);
293 qobject_unref(key);
295 return 0;
297 out:
298 qobject_unref(key);
300 return -1;
303 static QObject *parse_object(JSONParserContext *ctxt)
305 QDict *dict = NULL;
306 JSONToken *token, *peek;
308 token = parser_context_pop_token(ctxt);
309 assert(token && token->type == JSON_LCURLY);
311 dict = qdict_new();
313 peek = parser_context_peek_token(ctxt);
314 if (peek == NULL) {
315 parse_error(ctxt, NULL, "premature EOI");
316 goto out;
319 if (peek->type != JSON_RCURLY) {
320 if (parse_pair(ctxt, dict) == -1) {
321 goto out;
324 token = parser_context_pop_token(ctxt);
325 if (token == NULL) {
326 parse_error(ctxt, NULL, "premature EOI");
327 goto out;
330 while (token->type != JSON_RCURLY) {
331 if (token->type != JSON_COMMA) {
332 parse_error(ctxt, token, "expected separator in dict");
333 goto out;
336 if (parse_pair(ctxt, dict) == -1) {
337 goto out;
340 token = parser_context_pop_token(ctxt);
341 if (token == NULL) {
342 parse_error(ctxt, NULL, "premature EOI");
343 goto out;
346 } else {
347 (void)parser_context_pop_token(ctxt);
350 return QOBJECT(dict);
352 out:
353 qobject_unref(dict);
354 return NULL;
357 static QObject *parse_array(JSONParserContext *ctxt)
359 QList *list = NULL;
360 JSONToken *token, *peek;
362 token = parser_context_pop_token(ctxt);
363 assert(token && token->type == JSON_LSQUARE);
365 list = qlist_new();
367 peek = parser_context_peek_token(ctxt);
368 if (peek == NULL) {
369 parse_error(ctxt, NULL, "premature EOI");
370 goto out;
373 if (peek->type != JSON_RSQUARE) {
374 QObject *obj;
376 obj = parse_value(ctxt);
377 if (obj == NULL) {
378 parse_error(ctxt, token, "expecting value");
379 goto out;
382 qlist_append_obj(list, obj);
384 token = parser_context_pop_token(ctxt);
385 if (token == NULL) {
386 parse_error(ctxt, NULL, "premature EOI");
387 goto out;
390 while (token->type != JSON_RSQUARE) {
391 if (token->type != JSON_COMMA) {
392 parse_error(ctxt, token, "expected separator in list");
393 goto out;
396 obj = parse_value(ctxt);
397 if (obj == NULL) {
398 parse_error(ctxt, token, "expecting value");
399 goto out;
402 qlist_append_obj(list, obj);
404 token = parser_context_pop_token(ctxt);
405 if (token == NULL) {
406 parse_error(ctxt, NULL, "premature EOI");
407 goto out;
410 } else {
411 (void)parser_context_pop_token(ctxt);
414 return QOBJECT(list);
416 out:
417 qobject_unref(list);
418 return NULL;
421 static QObject *parse_keyword(JSONParserContext *ctxt)
423 JSONToken *token;
425 token = parser_context_pop_token(ctxt);
426 assert(token && token->type == JSON_KEYWORD);
428 if (!strcmp(token->str, "true")) {
429 return QOBJECT(qbool_from_bool(true));
430 } else if (!strcmp(token->str, "false")) {
431 return QOBJECT(qbool_from_bool(false));
432 } else if (!strcmp(token->str, "null")) {
433 return QOBJECT(qnull());
435 parse_error(ctxt, token, "invalid keyword '%s'", token->str);
436 return NULL;
439 static QObject *parse_interpolation(JSONParserContext *ctxt)
441 JSONToken *token;
443 token = parser_context_pop_token(ctxt);
444 assert(token && token->type == JSON_INTERP);
446 if (!strcmp(token->str, "%p")) {
447 return va_arg(*ctxt->ap, QObject *);
448 } else if (!strcmp(token->str, "%i")) {
449 return QOBJECT(qbool_from_bool(va_arg(*ctxt->ap, int)));
450 } else if (!strcmp(token->str, "%d")) {
451 return QOBJECT(qnum_from_int(va_arg(*ctxt->ap, int)));
452 } else if (!strcmp(token->str, "%ld")) {
453 return QOBJECT(qnum_from_int(va_arg(*ctxt->ap, long)));
454 } else if (!strcmp(token->str, "%lld")) {
455 return QOBJECT(qnum_from_int(va_arg(*ctxt->ap, long long)));
456 } else if (!strcmp(token->str, "%" PRId64)) {
457 return QOBJECT(qnum_from_int(va_arg(*ctxt->ap, int64_t)));
458 } else if (!strcmp(token->str, "%u")) {
459 return QOBJECT(qnum_from_uint(va_arg(*ctxt->ap, unsigned int)));
460 } else if (!strcmp(token->str, "%lu")) {
461 return QOBJECT(qnum_from_uint(va_arg(*ctxt->ap, unsigned long)));
462 } else if (!strcmp(token->str, "%llu")) {
463 return QOBJECT(qnum_from_uint(va_arg(*ctxt->ap, unsigned long long)));
464 } else if (!strcmp(token->str, "%" PRIu64)) {
465 return QOBJECT(qnum_from_uint(va_arg(*ctxt->ap, uint64_t)));
466 } else if (!strcmp(token->str, "%s")) {
467 return QOBJECT(qstring_from_str(va_arg(*ctxt->ap, const char *)));
468 } else if (!strcmp(token->str, "%f")) {
469 return QOBJECT(qnum_from_double(va_arg(*ctxt->ap, double)));
471 parse_error(ctxt, token, "invalid interpolation '%s'", token->str);
472 return NULL;
475 static QObject *parse_literal(JSONParserContext *ctxt)
477 JSONToken *token;
479 token = parser_context_pop_token(ctxt);
480 assert(token);
482 switch (token->type) {
483 case JSON_STRING:
484 return QOBJECT(parse_string(ctxt, token));
485 case JSON_INTEGER: {
487 * Represent JSON_INTEGER as QNUM_I64 if possible, else as
488 * QNUM_U64, else as QNUM_DOUBLE. Note that qemu_strtoi64()
489 * and qemu_strtou64() fail with ERANGE when it's not
490 * possible.
492 * qnum_get_int() will then work for any signed 64-bit
493 * JSON_INTEGER, qnum_get_uint() for any unsigned 64-bit
494 * integer, and qnum_get_double() both for any JSON_INTEGER
495 * and any JSON_FLOAT (with precision loss for integers beyond
496 * 53 bits)
498 int ret;
499 int64_t value;
500 uint64_t uvalue;
502 ret = qemu_strtoi64(token->str, NULL, 10, &value);
503 if (!ret) {
504 return QOBJECT(qnum_from_int(value));
506 assert(ret == -ERANGE);
508 if (token->str[0] != '-') {
509 ret = qemu_strtou64(token->str, NULL, 10, &uvalue);
510 if (!ret) {
511 return QOBJECT(qnum_from_uint(uvalue));
513 assert(ret == -ERANGE);
515 /* fall through to JSON_FLOAT */
517 case JSON_FLOAT:
518 /* FIXME dependent on locale; a pervasive issue in QEMU */
519 /* FIXME our lexer matches RFC 8259 in forbidding Inf or NaN,
520 * but those might be useful extensions beyond JSON */
521 return QOBJECT(qnum_from_double(strtod(token->str, NULL)));
522 default:
523 abort();
527 static QObject *parse_value(JSONParserContext *ctxt)
529 JSONToken *token;
531 token = parser_context_peek_token(ctxt);
532 if (token == NULL) {
533 parse_error(ctxt, NULL, "premature EOI");
534 return NULL;
537 switch (token->type) {
538 case JSON_LCURLY:
539 return parse_object(ctxt);
540 case JSON_LSQUARE:
541 return parse_array(ctxt);
542 case JSON_INTERP:
543 return parse_interpolation(ctxt);
544 case JSON_INTEGER:
545 case JSON_FLOAT:
546 case JSON_STRING:
547 return parse_literal(ctxt);
548 case JSON_KEYWORD:
549 return parse_keyword(ctxt);
550 default:
551 parse_error(ctxt, token, "expecting value");
552 return NULL;
556 JSONToken *json_token(JSONTokenType type, int x, int y, GString *tokstr)
558 JSONToken *token = g_malloc(sizeof(JSONToken) + tokstr->len + 1);
560 token->type = type;
561 memcpy(token->str, tokstr->str, tokstr->len);
562 token->str[tokstr->len] = 0;
563 token->x = x;
564 token->y = y;
565 return token;
568 QObject *json_parser_parse(GQueue *tokens, va_list *ap, Error **errp)
570 JSONParserContext ctxt = { .buf = tokens, .ap = ap };
571 QObject *result;
573 result = parse_value(&ctxt);
574 assert(ctxt.err || g_queue_is_empty(ctxt.buf));
576 error_propagate(errp, ctxt.err);
578 while (!g_queue_is_empty(ctxt.buf)) {
579 parser_context_pop_token(&ctxt);
581 g_free(ctxt.current);
583 return result;