1 /*-------------------------------------------------------------------------
2 *
3 * json.c
4 * JSON data type support.
5 *
6 * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
8 *
9 * IDENTIFICATION
10 * src/backend/utils/adt/json.c
11 *
12 *-------------------------------------------------------------------------
13 */
14 #include "postgres.h"
15
16 #include "access/htup_details.h"
17 #include "access/transam.h"
18 #include "catalog/pg_type.h"
19 #include "executor/spi.h"
20 #include "funcapi.h"
21 #include "lib/stringinfo.h"
22 #include "libpq/pqformat.h"
23 #include "mb/pg_wchar.h"
24 #include "miscadmin.h"
25 #include "parser/parse_coerce.h"
26 #include "utils/array.h"
27 #include "utils/builtins.h"
28 #include "utils/date.h"
29 #include "utils/datetime.h"
30 #include "utils/lsyscache.h"
31 #include "utils/json.h"
32 #include "utils/jsonapi.h"
33 #include "utils/typcache.h"
34 #include "utils/syscache.h"
35
36 /*
37 * The context of the parser is maintained by the recursive descent
38 * mechanism, but is passed explicitly to the error reporting routine
39 * for better diagnostics.
40 */
41 typedef enum /* contexts of JSON parser */
42 {
43 JSON_PARSE_VALUE, /* expecting a value */
44 JSON_PARSE_STRING, /* expecting a string (for a field name) */
45 JSON_PARSE_ARRAY_START, /* saw '[', expecting value or ']' */
46 JSON_PARSE_ARRAY_NEXT, /* saw array element, expecting ',' or ']' */
47 JSON_PARSE_OBJECT_START, /* saw '{', expecting label or '}' */
48 JSON_PARSE_OBJECT_LABEL, /* saw object label, expecting ':' */
49 JSON_PARSE_OBJECT_NEXT, /* saw object value, expecting ',' or '}' */
50 JSON_PARSE_OBJECT_COMMA, /* saw object ',', expecting next label */
51 JSON_PARSE_END /* saw the end of a document, expect nothing */
52 } JsonParseContext;
53
54 typedef enum /* type categories for datum_to_json */
55 {
56 JSONTYPE_NULL, /* null, so we didn't bother to identify */
57 JSONTYPE_BOOL, /* boolean (built-in types only) */
58 JSONTYPE_NUMERIC, /* numeric (ditto) */
59 JSONTYPE_DATE, /* we use special formatting for datetimes */
60 JSONTYPE_TIMESTAMP,
61 JSONTYPE_TIMESTAMPTZ,
62 JSONTYPE_JSON, /* JSON itself (and JSONB) */
63 JSONTYPE_ARRAY, /* array */
64 JSONTYPE_COMPOSITE, /* composite */
65 JSONTYPE_CAST, /* something with an explicit cast to JSON */
66 JSONTYPE_OTHER /* all else */
67 } JsonTypeCategory;
68
69 typedef struct JsonAggState
70 {
71 StringInfo str;
72 JsonTypeCategory key_category;
73 Oid key_output_func;
74 JsonTypeCategory val_category;
75 Oid val_output_func;
76 } JsonAggState;
77
78 static inline void json_lex(JsonLexContext *lex);
79 static inline void json_lex_string(JsonLexContext *lex);
80 static inline void json_lex_number(JsonLexContext *lex, char *s,
81 bool *num_err, int *total_len);
82 static inline void parse_scalar(JsonLexContext *lex, JsonSemAction *sem);
83 static void parse_object_field(JsonLexContext *lex, JsonSemAction *sem);
84 static void parse_object(JsonLexContext *lex, JsonSemAction *sem);
85 static void parse_array_element(JsonLexContext *lex, JsonSemAction *sem);
86 static void parse_array(JsonLexContext *lex, JsonSemAction *sem);
87 static void report_parse_error(JsonParseContext ctx, JsonLexContext *lex);
88 static void report_invalid_token(JsonLexContext *lex);
89 static int report_json_context(JsonLexContext *lex);
90 static char *extract_mb_char(char *s);
91 static void composite_to_json(Datum composite, StringInfo result,
92 bool use_line_feeds);
93 static void array_dim_to_json(StringInfo result, int dim, int ndims, int *dims,
94 Datum *vals, bool *nulls, int *valcount,
95 JsonTypeCategory tcategory, Oid outfuncoid,
96 bool use_line_feeds);
97 static void array_to_json_internal(Datum array, StringInfo result,
98 bool use_line_feeds);
99 static void json_categorize_type(Oid typoid,
100 JsonTypeCategory *tcategory,
101 Oid *outfuncoid);
102 static void datum_to_json(Datum val, bool is_null, StringInfo result,
103 JsonTypeCategory tcategory, Oid outfuncoid,
104 bool key_scalar);
105 static void add_json(Datum val, bool is_null, StringInfo result,
106 Oid val_type, bool key_scalar);
107 static text *catenate_stringinfo_string(StringInfo buffer, const char *addon);
108
109 /* the null action object used for pure validation */
110 static JsonSemAction nullSemAction =
111 {
112 NULL, NULL, NULL, NULL, NULL,
113 NULL, NULL, NULL, NULL, NULL
114 };
115
116 /* Recursive Descent parser support routines */
117
118 /*
119 * lex_peek
120 *
121 * what is the current look_ahead token?
122 */
123 static inline JsonTokenType
lex_peek(JsonLexContext * lex)124 lex_peek(JsonLexContext *lex)
125 {
126 return lex->token_type;
127 }
128
129 /*
130 * lex_accept
131 *
132 * accept the look_ahead token and move the lexer to the next token if the
133 * look_ahead token matches the token parameter. In that case, and if required,
134 * also hand back the de-escaped lexeme.
135 *
136 * returns true if the token matched, false otherwise.
137 */
138 static inline bool
lex_accept(JsonLexContext * lex,JsonTokenType token,char ** lexeme)139 lex_accept(JsonLexContext *lex, JsonTokenType token, char **lexeme)
140 {
141 if (lex->token_type == token)
142 {
143 if (lexeme != NULL)
144 {
145 if (lex->token_type == JSON_TOKEN_STRING)
146 {
147 if (lex->strval != NULL)
148 *lexeme = pstrdup(lex->strval->data);
149 }
150 else
151 {
152 int len = (lex->token_terminator - lex->token_start);
153 char *tokstr = palloc(len + 1);
154
155 memcpy(tokstr, lex->token_start, len);
156 tokstr[len] = '\0';
157 *lexeme = tokstr;
158 }
159 }
160 json_lex(lex);
161 return true;
162 }
163 return false;
164 }
165
166 /*
167 * lex_accept
168 *
169 * move the lexer to the next token if the current look_ahead token matches
170 * the parameter token. Otherwise, report an error.
171 */
172 static inline void
lex_expect(JsonParseContext ctx,JsonLexContext * lex,JsonTokenType token)173 lex_expect(JsonParseContext ctx, JsonLexContext *lex, JsonTokenType token)
174 {
175 if (!lex_accept(lex, token, NULL))
176 report_parse_error(ctx, lex);
177 }
178
179 /* chars to consider as part of an alphanumeric token */
180 #define JSON_ALPHANUMERIC_CHAR(c) \
181 (((c) >= 'a' && (c) <= 'z') || \
182 ((c) >= 'A' && (c) <= 'Z') || \
183 ((c) >= '0' && (c) <= '9') || \
184 (c) == '_' || \
185 IS_HIGHBIT_SET(c))
186
187 /*
188 * Utility function to check if a string is a valid JSON number.
189 *
190 * str is of length len, and need not be null-terminated.
191 */
192 bool
IsValidJsonNumber(const char * str,int len)193 IsValidJsonNumber(const char *str, int len)
194 {
195 bool numeric_error;
196 int total_len;
197 JsonLexContext dummy_lex;
198
199 if (len <= 0)
200 return false;
201
202 /*
203 * json_lex_number expects a leading '-' to have been eaten already.
204 *
205 * having to cast away the constness of str is ugly, but there's not much
206 * easy alternative.
207 */
208 if (*str == '-')
209 {
210 dummy_lex.input = (char *) str + 1;
211 dummy_lex.input_length = len - 1;
212 }
213 else
214 {
215 dummy_lex.input = (char *) str;
216 dummy_lex.input_length = len;
217 }
218
219 json_lex_number(&dummy_lex, dummy_lex.input, &numeric_error, &total_len);
220
221 return (!numeric_error) && (total_len == dummy_lex.input_length);
222 }
223
224 /*
225 * Input.
226 */
227 Datum
json_in(PG_FUNCTION_ARGS)228 json_in(PG_FUNCTION_ARGS)
229 {
230 char *json = PG_GETARG_CSTRING(0);
231 text *result = cstring_to_text(json);
232 JsonLexContext *lex;
233
234 /* validate it */
235 lex = makeJsonLexContext(result, false);
236 pg_parse_json(lex, &nullSemAction);
237
238 /* Internal representation is the same as text, for now */
239 PG_RETURN_TEXT_P(result);
240 }
241
242 /*
243 * Output.
244 */
245 Datum
json_out(PG_FUNCTION_ARGS)246 json_out(PG_FUNCTION_ARGS)
247 {
248 /* we needn't detoast because text_to_cstring will handle that */
249 Datum txt = PG_GETARG_DATUM(0);
250
251 PG_RETURN_CSTRING(TextDatumGetCString(txt));
252 }
253
254 /*
255 * Binary send.
256 */
257 Datum
json_send(PG_FUNCTION_ARGS)258 json_send(PG_FUNCTION_ARGS)
259 {
260 text *t = PG_GETARG_TEXT_PP(0);
261 StringInfoData buf;
262
263 pq_begintypsend(&buf);
264 pq_sendtext(&buf, VARDATA_ANY(t), VARSIZE_ANY_EXHDR(t));
265 PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
266 }
267
268 /*
269 * Binary receive.
270 */
271 Datum
json_recv(PG_FUNCTION_ARGS)272 json_recv(PG_FUNCTION_ARGS)
273 {
274 StringInfo buf = (StringInfo) PG_GETARG_POINTER(0);
275 char *str;
276 int nbytes;
277 JsonLexContext *lex;
278
279 str = pq_getmsgtext(buf, buf->len - buf->cursor, &nbytes);
280
281 /* Validate it. */
282 lex = makeJsonLexContextCstringLen(str, nbytes, false);
283 pg_parse_json(lex, &nullSemAction);
284
285 PG_RETURN_TEXT_P(cstring_to_text_with_len(str, nbytes));
286 }
287
288 /*
289 * makeJsonLexContext
290 *
291 * lex constructor, with or without StringInfo object
292 * for de-escaped lexemes.
293 *
294 * Without is better as it makes the processing faster, so only make one
295 * if really required.
296 *
297 * If you already have the json as a text* value, use the first of these
298 * functions, otherwise use makeJsonLexContextCstringLen().
299 */
300 JsonLexContext *
makeJsonLexContext(text * json,bool need_escapes)301 makeJsonLexContext(text *json, bool need_escapes)
302 {
303 return makeJsonLexContextCstringLen(VARDATA_ANY(json),
304 VARSIZE_ANY_EXHDR(json),
305 need_escapes);
306 }
307
308 JsonLexContext *
makeJsonLexContextCstringLen(char * json,int len,bool need_escapes)309 makeJsonLexContextCstringLen(char *json, int len, bool need_escapes)
310 {
311 JsonLexContext *lex = palloc0(sizeof(JsonLexContext));
312
313 lex->input = lex->token_terminator = lex->line_start = json;
314 lex->line_number = 1;
315 lex->input_length = len;
316 if (need_escapes)
317 lex->strval = makeStringInfo();
318 return lex;
319 }
320
321 /*
322 * pg_parse_json
323 *
324 * Publicly visible entry point for the JSON parser.
325 *
326 * lex is a lexing context, set up for the json to be processed by calling
327 * makeJsonLexContext(). sem is a structure of function pointers to semantic
328 * action routines to be called at appropriate spots during parsing, and a
329 * pointer to a state object to be passed to those routines.
330 */
331 void
pg_parse_json(JsonLexContext * lex,JsonSemAction * sem)332 pg_parse_json(JsonLexContext *lex, JsonSemAction *sem)
333 {
334 JsonTokenType tok;
335
336 /* get the initial token */
337 json_lex(lex);
338
339 tok = lex_peek(lex);
340
341 /* parse by recursive descent */
342 switch (tok)
343 {
344 case JSON_TOKEN_OBJECT_START:
345 parse_object(lex, sem);
346 break;
347 case JSON_TOKEN_ARRAY_START:
348 parse_array(lex, sem);
349 break;
350 default:
351 parse_scalar(lex, sem); /* json can be a bare scalar */
352 }
353
354 lex_expect(JSON_PARSE_END, lex, JSON_TOKEN_END);
355
356 }
357
358 /*
359 * json_count_array_elements
360 *
361 * Returns number of array elements in lex context at start of array token
362 * until end of array token at same nesting level.
363 *
364 * Designed to be called from array_start routines.
365 */
366 int
json_count_array_elements(JsonLexContext * lex)367 json_count_array_elements(JsonLexContext *lex)
368 {
369 JsonLexContext copylex;
370 int count;
371
372 /*
373 * It's safe to do this with a shallow copy because the lexical routines
374 * don't scribble on the input. They do scribble on the other pointers
375 * etc, so doing this with a copy makes that safe.
376 */
377 memcpy(©lex, lex, sizeof(JsonLexContext));
378 copylex.strval = NULL; /* not interested in values here */
379 copylex.lex_level++;
380
381 count = 0;
382 lex_expect(JSON_PARSE_ARRAY_START, ©lex, JSON_TOKEN_ARRAY_START);
383 if (lex_peek(©lex) != JSON_TOKEN_ARRAY_END)
384 {
385 do
386 {
387 count++;
388 parse_array_element(©lex, &nullSemAction);
389 }
390 while (lex_accept(©lex, JSON_TOKEN_COMMA, NULL));
391 }
392 lex_expect(JSON_PARSE_ARRAY_NEXT, ©lex, JSON_TOKEN_ARRAY_END);
393
394 return count;
395 }
396
397 /*
398 * Recursive Descent parse routines. There is one for each structural
399 * element in a json document:
400 * - scalar (string, number, true, false, null)
401 * - array ( [ ] )
402 * - array element
403 * - object ( { } )
404 * - object field
405 */
406 static inline void
parse_scalar(JsonLexContext * lex,JsonSemAction * sem)407 parse_scalar(JsonLexContext *lex, JsonSemAction *sem)
408 {
409 char *val = NULL;
410 json_scalar_action sfunc = sem->scalar;
411 char **valaddr;
412 JsonTokenType tok = lex_peek(lex);
413
414 valaddr = sfunc == NULL ? NULL : &val;
415
416 /* a scalar must be a string, a number, true, false, or null */
417 switch (tok)
418 {
419 case JSON_TOKEN_TRUE:
420 lex_accept(lex, JSON_TOKEN_TRUE, valaddr);
421 break;
422 case JSON_TOKEN_FALSE:
423 lex_accept(lex, JSON_TOKEN_FALSE, valaddr);
424 break;
425 case JSON_TOKEN_NULL:
426 lex_accept(lex, JSON_TOKEN_NULL, valaddr);
427 break;
428 case JSON_TOKEN_NUMBER:
429 lex_accept(lex, JSON_TOKEN_NUMBER, valaddr);
430 break;
431 case JSON_TOKEN_STRING:
432 lex_accept(lex, JSON_TOKEN_STRING, valaddr);
433 break;
434 default:
435 report_parse_error(JSON_PARSE_VALUE, lex);
436 }
437
438 if (sfunc != NULL)
439 (*sfunc) (sem->semstate, val, tok);
440 }
441
442 static void
parse_object_field(JsonLexContext * lex,JsonSemAction * sem)443 parse_object_field(JsonLexContext *lex, JsonSemAction *sem)
444 {
445 /*
446 * An object field is "fieldname" : value where value can be a scalar,
447 * object or array. Note: in user-facing docs and error messages, we
448 * generally call a field name a "key".
449 */
450
451 char *fname = NULL; /* keep compiler quiet */
452 json_ofield_action ostart = sem->object_field_start;
453 json_ofield_action oend = sem->object_field_end;
454 bool isnull;
455 char **fnameaddr = NULL;
456 JsonTokenType tok;
457
458 if (ostart != NULL || oend != NULL)
459 fnameaddr = &fname;
460
461 if (!lex_accept(lex, JSON_TOKEN_STRING, fnameaddr))
462 report_parse_error(JSON_PARSE_STRING, lex);
463
464 lex_expect(JSON_PARSE_OBJECT_LABEL, lex, JSON_TOKEN_COLON);
465
466 tok = lex_peek(lex);
467 isnull = tok == JSON_TOKEN_NULL;
468
469 if (ostart != NULL)
470 (*ostart) (sem->semstate, fname, isnull);
471
472 switch (tok)
473 {
474 case JSON_TOKEN_OBJECT_START:
475 parse_object(lex, sem);
476 break;
477 case JSON_TOKEN_ARRAY_START:
478 parse_array(lex, sem);
479 break;
480 default:
481 parse_scalar(lex, sem);
482 }
483
484 if (oend != NULL)
485 (*oend) (sem->semstate, fname, isnull);
486 }
487
488 static void
parse_object(JsonLexContext * lex,JsonSemAction * sem)489 parse_object(JsonLexContext *lex, JsonSemAction *sem)
490 {
491 /*
492 * an object is a possibly empty sequence of object fields, separated by
493 * commas and surrounded by curly braces.
494 */
495 json_struct_action ostart = sem->object_start;
496 json_struct_action oend = sem->object_end;
497 JsonTokenType tok;
498
499 check_stack_depth();
500
501 if (ostart != NULL)
502 (*ostart) (sem->semstate);
503
504 /*
505 * Data inside an object is at a higher nesting level than the object
506 * itself. Note that we increment this after we call the semantic routine
507 * for the object start and restore it before we call the routine for the
508 * object end.
509 */
510 lex->lex_level++;
511
512 /* we know this will succeed, just clearing the token */
513 lex_expect(JSON_PARSE_OBJECT_START, lex, JSON_TOKEN_OBJECT_START);
514
515 tok = lex_peek(lex);
516 switch (tok)
517 {
518 case JSON_TOKEN_STRING:
519 parse_object_field(lex, sem);
520 while (lex_accept(lex, JSON_TOKEN_COMMA, NULL))
521 parse_object_field(lex, sem);
522 break;
523 case JSON_TOKEN_OBJECT_END:
524 break;
525 default:
526 /* case of an invalid initial token inside the object */
527 report_parse_error(JSON_PARSE_OBJECT_START, lex);
528 }
529
530 lex_expect(JSON_PARSE_OBJECT_NEXT, lex, JSON_TOKEN_OBJECT_END);
531
532 lex->lex_level--;
533
534 if (oend != NULL)
535 (*oend) (sem->semstate);
536 }
537
538 static void
parse_array_element(JsonLexContext * lex,JsonSemAction * sem)539 parse_array_element(JsonLexContext *lex, JsonSemAction *sem)
540 {
541 json_aelem_action astart = sem->array_element_start;
542 json_aelem_action aend = sem->array_element_end;
543 JsonTokenType tok = lex_peek(lex);
544
545 bool isnull;
546
547 isnull = tok == JSON_TOKEN_NULL;
548
549 if (astart != NULL)
550 (*astart) (sem->semstate, isnull);
551
552 /* an array element is any object, array or scalar */
553 switch (tok)
554 {
555 case JSON_TOKEN_OBJECT_START:
556 parse_object(lex, sem);
557 break;
558 case JSON_TOKEN_ARRAY_START:
559 parse_array(lex, sem);
560 break;
561 default:
562 parse_scalar(lex, sem);
563 }
564
565 if (aend != NULL)
566 (*aend) (sem->semstate, isnull);
567 }
568
569 static void
parse_array(JsonLexContext * lex,JsonSemAction * sem)570 parse_array(JsonLexContext *lex, JsonSemAction *sem)
571 {
572 /*
573 * an array is a possibly empty sequence of array elements, separated by
574 * commas and surrounded by square brackets.
575 */
576 json_struct_action astart = sem->array_start;
577 json_struct_action aend = sem->array_end;
578
579 check_stack_depth();
580
581 if (astart != NULL)
582 (*astart) (sem->semstate);
583
584 /*
585 * Data inside an array is at a higher nesting level than the array
586 * itself. Note that we increment this after we call the semantic routine
587 * for the array start and restore it before we call the routine for the
588 * array end.
589 */
590 lex->lex_level++;
591
592 lex_expect(JSON_PARSE_ARRAY_START, lex, JSON_TOKEN_ARRAY_START);
593 if (lex_peek(lex) != JSON_TOKEN_ARRAY_END)
594 {
595
596 parse_array_element(lex, sem);
597
598 while (lex_accept(lex, JSON_TOKEN_COMMA, NULL))
599 parse_array_element(lex, sem);
600 }
601
602 lex_expect(JSON_PARSE_ARRAY_NEXT, lex, JSON_TOKEN_ARRAY_END);
603
604 lex->lex_level--;
605
606 if (aend != NULL)
607 (*aend) (sem->semstate);
608 }
609
610 /*
611 * Lex one token from the input stream.
612 */
613 static inline void
json_lex(JsonLexContext * lex)614 json_lex(JsonLexContext *lex)
615 {
616 char *s;
617 int len;
618
619 /* Skip leading whitespace. */
620 s = lex->token_terminator;
621 len = s - lex->input;
622 while (len < lex->input_length &&
623 (*s == ' ' || *s == '\t' || *s == '\n' || *s == '\r'))
624 {
625 if (*s == '\n')
626 ++lex->line_number;
627 ++s;
628 ++len;
629 }
630 lex->token_start = s;
631
632 /* Determine token type. */
633 if (len >= lex->input_length)
634 {
635 lex->token_start = NULL;
636 lex->prev_token_terminator = lex->token_terminator;
637 lex->token_terminator = s;
638 lex->token_type = JSON_TOKEN_END;
639 }
640 else
641 switch (*s)
642 {
643 /* Single-character token, some kind of punctuation mark. */
644 case '{':
645 lex->prev_token_terminator = lex->token_terminator;
646 lex->token_terminator = s + 1;
647 lex->token_type = JSON_TOKEN_OBJECT_START;
648 break;
649 case '}':
650 lex->prev_token_terminator = lex->token_terminator;
651 lex->token_terminator = s + 1;
652 lex->token_type = JSON_TOKEN_OBJECT_END;
653 break;
654 case '[':
655 lex->prev_token_terminator = lex->token_terminator;
656 lex->token_terminator = s + 1;
657 lex->token_type = JSON_TOKEN_ARRAY_START;
658 break;
659 case ']':
660 lex->prev_token_terminator = lex->token_terminator;
661 lex->token_terminator = s + 1;
662 lex->token_type = JSON_TOKEN_ARRAY_END;
663 break;
664 case ',':
665 lex->prev_token_terminator = lex->token_terminator;
666 lex->token_terminator = s + 1;
667 lex->token_type = JSON_TOKEN_COMMA;
668 break;
669 case ':':
670 lex->prev_token_terminator = lex->token_terminator;
671 lex->token_terminator = s + 1;
672 lex->token_type = JSON_TOKEN_COLON;
673 break;
674 case '"':
675 /* string */
676 json_lex_string(lex);
677 lex->token_type = JSON_TOKEN_STRING;
678 break;
679 case '-':
680 /* Negative number. */
681 json_lex_number(lex, s + 1, NULL, NULL);
682 lex->token_type = JSON_TOKEN_NUMBER;
683 break;
684 case '0':
685 case '1':
686 case '2':
687 case '3':
688 case '4':
689 case '5':
690 case '6':
691 case '7':
692 case '8':
693 case '9':
694 /* Positive number. */
695 json_lex_number(lex, s, NULL, NULL);
696 lex->token_type = JSON_TOKEN_NUMBER;
697 break;
698 default:
699 {
700 char *p;
701
702 /*
703 * We're not dealing with a string, number, legal
704 * punctuation mark, or end of string. The only legal
705 * tokens we might find here are true, false, and null,
706 * but for error reporting purposes we scan until we see a
707 * non-alphanumeric character. That way, we can report
708 * the whole word as an unexpected token, rather than just
709 * some unintuitive prefix thereof.
710 */
711 for (p = s; p - s < lex->input_length - len && JSON_ALPHANUMERIC_CHAR(*p); p++)
712 /* skip */ ;
713
714 /*
715 * We got some sort of unexpected punctuation or an
716 * otherwise unexpected character, so just complain about
717 * that one character.
718 */
719 if (p == s)
720 {
721 lex->prev_token_terminator = lex->token_terminator;
722 lex->token_terminator = s + 1;
723 report_invalid_token(lex);
724 }
725
726 /*
727 * We've got a real alphanumeric token here. If it
728 * happens to be true, false, or null, all is well. If
729 * not, error out.
730 */
731 lex->prev_token_terminator = lex->token_terminator;
732 lex->token_terminator = p;
733 if (p - s == 4)
734 {
735 if (memcmp(s, "true", 4) == 0)
736 lex->token_type = JSON_TOKEN_TRUE;
737 else if (memcmp(s, "null", 4) == 0)
738 lex->token_type = JSON_TOKEN_NULL;
739 else
740 report_invalid_token(lex);
741 }
742 else if (p - s == 5 && memcmp(s, "false", 5) == 0)
743 lex->token_type = JSON_TOKEN_FALSE;
744 else
745 report_invalid_token(lex);
746
747 }
748 } /* end of switch */
749 }
750
751 /*
752 * The next token in the input stream is known to be a string; lex it.
753 */
754 static inline void
json_lex_string(JsonLexContext * lex)755 json_lex_string(JsonLexContext *lex)
756 {
757 char *s;
758 int len;
759 int hi_surrogate = -1;
760
761 if (lex->strval != NULL)
762 resetStringInfo(lex->strval);
763
764 Assert(lex->input_length > 0);
765 s = lex->token_start;
766 len = lex->token_start - lex->input;
767 for (;;)
768 {
769 s++;
770 len++;
771 /* Premature end of the string. */
772 if (len >= lex->input_length)
773 {
774 lex->token_terminator = s;
775 report_invalid_token(lex);
776 }
777 else if (*s == '"')
778 break;
779 else if ((unsigned char) *s < 32)
780 {
781 /* Per RFC4627, these characters MUST be escaped. */
782 /* Since *s isn't printable, exclude it from the context string */
783 lex->token_terminator = s;
784 ereport(ERROR,
785 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
786 errmsg("invalid input syntax for type %s", "json"),
787 errdetail("Character with value 0x%02x must be escaped.",
788 (unsigned char) *s),
789 report_json_context(lex)));
790 }
791 else if (*s == '\\')
792 {
793 /* OK, we have an escape character. */
794 s++;
795 len++;
796 if (len >= lex->input_length)
797 {
798 lex->token_terminator = s;
799 report_invalid_token(lex);
800 }
801 else if (*s == 'u')
802 {
803 int i;
804 int ch = 0;
805
806 for (i = 1; i <= 4; i++)
807 {
808 s++;
809 len++;
810 if (len >= lex->input_length)
811 {
812 lex->token_terminator = s;
813 report_invalid_token(lex);
814 }
815 else if (*s >= '0' && *s <= '9')
816 ch = (ch * 16) + (*s - '0');
817 else if (*s >= 'a' && *s <= 'f')
818 ch = (ch * 16) + (*s - 'a') + 10;
819 else if (*s >= 'A' && *s <= 'F')
820 ch = (ch * 16) + (*s - 'A') + 10;
821 else
822 {
823 lex->token_terminator = s + pg_mblen(s);
824 ereport(ERROR,
825 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
826 errmsg("invalid input syntax for type %s",
827 "json"),
828 errdetail("\"\\u\" must be followed by four hexadecimal digits."),
829 report_json_context(lex)));
830 }
831 }
832 if (lex->strval != NULL)
833 {
834 char utf8str[5];
835 int utf8len;
836
837 if (ch >= 0xd800 && ch <= 0xdbff)
838 {
839 if (hi_surrogate != -1)
840 ereport(ERROR,
841 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
842 errmsg("invalid input syntax for type %s",
843 "json"),
844 errdetail("Unicode high surrogate must not follow a high surrogate."),
845 report_json_context(lex)));
846 hi_surrogate = (ch & 0x3ff) << 10;
847 continue;
848 }
849 else if (ch >= 0xdc00 && ch <= 0xdfff)
850 {
851 if (hi_surrogate == -1)
852 ereport(ERROR,
853 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
854 errmsg("invalid input syntax for type %s", "json"),
855 errdetail("Unicode low surrogate must follow a high surrogate."),
856 report_json_context(lex)));
857 ch = 0x10000 + hi_surrogate + (ch & 0x3ff);
858 hi_surrogate = -1;
859 }
860
861 if (hi_surrogate != -1)
862 ereport(ERROR,
863 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
864 errmsg("invalid input syntax for type %s", "json"),
865 errdetail("Unicode low surrogate must follow a high surrogate."),
866 report_json_context(lex)));
867
868 /*
869 * For UTF8, replace the escape sequence by the actual
870 * utf8 character in lex->strval. Do this also for other
871 * encodings if the escape designates an ASCII character,
872 * otherwise raise an error.
873 */
874
875 if (ch == 0)
876 {
877 /* We can't allow this, since our TEXT type doesn't */
878 ereport(ERROR,
879 (errcode(ERRCODE_UNTRANSLATABLE_CHARACTER),
880 errmsg("unsupported Unicode escape sequence"),
881 errdetail("\\u0000 cannot be converted to text."),
882 report_json_context(lex)));
883 }
884 else if (GetDatabaseEncoding() == PG_UTF8)
885 {
886 unicode_to_utf8(ch, (unsigned char *) utf8str);
887 utf8len = pg_utf_mblen((unsigned char *) utf8str);
888 appendBinaryStringInfo(lex->strval, utf8str, utf8len);
889 }
890 else if (ch <= 0x007f)
891 {
892 /*
893 * This is the only way to designate things like a
894 * form feed character in JSON, so it's useful in all
895 * encodings.
896 */
897 appendStringInfoChar(lex->strval, (char) ch);
898 }
899 else
900 {
901 ereport(ERROR,
902 (errcode(ERRCODE_UNTRANSLATABLE_CHARACTER),
903 errmsg("unsupported Unicode escape sequence"),
904 errdetail("Unicode escape values cannot be used for code point values above 007F when the server encoding is not UTF8."),
905 report_json_context(lex)));
906 }
907
908 }
909 }
910 else if (lex->strval != NULL)
911 {
912 if (hi_surrogate != -1)
913 ereport(ERROR,
914 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
915 errmsg("invalid input syntax for type %s",
916 "json"),
917 errdetail("Unicode low surrogate must follow a high surrogate."),
918 report_json_context(lex)));
919
920 switch (*s)
921 {
922 case '"':
923 case '\\':
924 case '/':
925 appendStringInfoChar(lex->strval, *s);
926 break;
927 case 'b':
928 appendStringInfoChar(lex->strval, '\b');
929 break;
930 case 'f':
931 appendStringInfoChar(lex->strval, '\f');
932 break;
933 case 'n':
934 appendStringInfoChar(lex->strval, '\n');
935 break;
936 case 'r':
937 appendStringInfoChar(lex->strval, '\r');
938 break;
939 case 't':
940 appendStringInfoChar(lex->strval, '\t');
941 break;
942 default:
943 /* Not a valid string escape, so error out. */
944 lex->token_terminator = s + pg_mblen(s);
945 ereport(ERROR,
946 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
947 errmsg("invalid input syntax for type %s",
948 "json"),
949 errdetail("Escape sequence \"\\%s\" is invalid.",
950 extract_mb_char(s)),
951 report_json_context(lex)));
952 }
953 }
954 else if (strchr("\"\\/bfnrt", *s) == NULL)
955 {
956 /*
957 * Simpler processing if we're not bothered about de-escaping
958 *
959 * It's very tempting to remove the strchr() call here and
960 * replace it with a switch statement, but testing so far has
961 * shown it's not a performance win.
962 */
963 lex->token_terminator = s + pg_mblen(s);
964 ereport(ERROR,
965 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
966 errmsg("invalid input syntax for type %s", "json"),
967 errdetail("Escape sequence \"\\%s\" is invalid.",
968 extract_mb_char(s)),
969 report_json_context(lex)));
970 }
971
972 }
973 else if (lex->strval != NULL)
974 {
975 if (hi_surrogate != -1)
976 ereport(ERROR,
977 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
978 errmsg("invalid input syntax for type %s", "json"),
979 errdetail("Unicode low surrogate must follow a high surrogate."),
980 report_json_context(lex)));
981
982 appendStringInfoChar(lex->strval, *s);
983 }
984
985 }
986
987 if (hi_surrogate != -1)
988 ereport(ERROR,
989 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
990 errmsg("invalid input syntax for type %s", "json"),
991 errdetail("Unicode low surrogate must follow a high surrogate."),
992 report_json_context(lex)));
993
994 /* Hooray, we found the end of the string! */
995 lex->prev_token_terminator = lex->token_terminator;
996 lex->token_terminator = s + 1;
997 }
998
999 /*
1000 * The next token in the input stream is known to be a number; lex it.
1001 *
1002 * In JSON, a number consists of four parts:
1003 *
1004 * (1) An optional minus sign ('-').
1005 *
1006 * (2) Either a single '0', or a string of one or more digits that does not
1007 * begin with a '0'.
1008 *
1009 * (3) An optional decimal part, consisting of a period ('.') followed by
1010 * one or more digits. (Note: While this part can be omitted
1011 * completely, it's not OK to have only the decimal point without
1012 * any digits afterwards.)
1013 *
1014 * (4) An optional exponent part, consisting of 'e' or 'E', optionally
1015 * followed by '+' or '-', followed by one or more digits. (Note:
1016 * As with the decimal part, if 'e' or 'E' is present, it must be
1017 * followed by at least one digit.)
1018 *
1019 * The 's' argument to this function points to the ostensible beginning
1020 * of part 2 - i.e. the character after any optional minus sign, or the
1021 * first character of the string if there is none.
1022 *
1023 * If num_err is not NULL, we return an error flag to *num_err rather than
1024 * raising an error for a badly-formed number. Also, if total_len is not NULL
1025 * the distance from lex->input to the token end+1 is returned to *total_len.
1026 */
1027 static inline void
json_lex_number(JsonLexContext * lex,char * s,bool * num_err,int * total_len)1028 json_lex_number(JsonLexContext *lex, char *s,
1029 bool *num_err, int *total_len)
1030 {
1031 bool error = false;
1032 int len = s - lex->input;
1033
1034 /* Part (1): leading sign indicator. */
1035 /* Caller already did this for us; so do nothing. */
1036
1037 /* Part (2): parse main digit string. */
1038 if (len < lex->input_length && *s == '0')
1039 {
1040 s++;
1041 len++;
1042 }
1043 else if (len < lex->input_length && *s >= '1' && *s <= '9')
1044 {
1045 do
1046 {
1047 s++;
1048 len++;
1049 } while (len < lex->input_length && *s >= '0' && *s <= '9');
1050 }
1051 else
1052 error = true;
1053
1054 /* Part (3): parse optional decimal portion. */
1055 if (len < lex->input_length && *s == '.')
1056 {
1057 s++;
1058 len++;
1059 if (len == lex->input_length || *s < '0' || *s > '9')
1060 error = true;
1061 else
1062 {
1063 do
1064 {
1065 s++;
1066 len++;
1067 } while (len < lex->input_length && *s >= '0' && *s <= '9');
1068 }
1069 }
1070
1071 /* Part (4): parse optional exponent. */
1072 if (len < lex->input_length && (*s == 'e' || *s == 'E'))
1073 {
1074 s++;
1075 len++;
1076 if (len < lex->input_length && (*s == '+' || *s == '-'))
1077 {
1078 s++;
1079 len++;
1080 }
1081 if (len == lex->input_length || *s < '0' || *s > '9')
1082 error = true;
1083 else
1084 {
1085 do
1086 {
1087 s++;
1088 len++;
1089 } while (len < lex->input_length && *s >= '0' && *s <= '9');
1090 }
1091 }
1092
1093 /*
1094 * Check for trailing garbage. As in json_lex(), any alphanumeric stuff
1095 * here should be considered part of the token for error-reporting
1096 * purposes.
1097 */
1098 for (; len < lex->input_length && JSON_ALPHANUMERIC_CHAR(*s); s++, len++)
1099 error = true;
1100
1101 if (total_len != NULL)
1102 *total_len = len;
1103
1104 if (num_err != NULL)
1105 {
1106 /* let the caller handle any error */
1107 *num_err = error;
1108 }
1109 else
1110 {
1111 /* return token endpoint */
1112 lex->prev_token_terminator = lex->token_terminator;
1113 lex->token_terminator = s;
1114 /* handle error if any */
1115 if (error)
1116 report_invalid_token(lex);
1117 }
1118 }
1119
1120 /*
1121 * Report a parse error.
1122 *
1123 * lex->token_start and lex->token_terminator must identify the current token.
1124 */
1125 static void
report_parse_error(JsonParseContext ctx,JsonLexContext * lex)1126 report_parse_error(JsonParseContext ctx, JsonLexContext *lex)
1127 {
1128 char *token;
1129 int toklen;
1130
1131 /* Handle case where the input ended prematurely. */
1132 if (lex->token_start == NULL || lex->token_type == JSON_TOKEN_END)
1133 ereport(ERROR,
1134 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
1135 errmsg("invalid input syntax for type %s", "json"),
1136 errdetail("The input string ended unexpectedly."),
1137 report_json_context(lex)));
1138
1139 /* Separate out the current token. */
1140 toklen = lex->token_terminator - lex->token_start;
1141 token = palloc(toklen + 1);
1142 memcpy(token, lex->token_start, toklen);
1143 token[toklen] = '\0';
1144
1145 /* Complain, with the appropriate detail message. */
1146 if (ctx == JSON_PARSE_END)
1147 ereport(ERROR,
1148 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
1149 errmsg("invalid input syntax for type %s", "json"),
1150 errdetail("Expected end of input, but found \"%s\".",
1151 token),
1152 report_json_context(lex)));
1153 else
1154 {
1155 switch (ctx)
1156 {
1157 case JSON_PARSE_VALUE:
1158 ereport(ERROR,
1159 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
1160 errmsg("invalid input syntax for type %s", "json"),
1161 errdetail("Expected JSON value, but found \"%s\".",
1162 token),
1163 report_json_context(lex)));
1164 break;
1165 case JSON_PARSE_STRING:
1166 ereport(ERROR,
1167 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
1168 errmsg("invalid input syntax for type %s", "json"),
1169 errdetail("Expected string, but found \"%s\".",
1170 token),
1171 report_json_context(lex)));
1172 break;
1173 case JSON_PARSE_ARRAY_START:
1174 ereport(ERROR,
1175 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
1176 errmsg("invalid input syntax for type %s", "json"),
1177 errdetail("Expected array element or \"]\", but found \"%s\".",
1178 token),
1179 report_json_context(lex)));
1180 break;
1181 case JSON_PARSE_ARRAY_NEXT:
1182 ereport(ERROR,
1183 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
1184 errmsg("invalid input syntax for type %s", "json"),
1185 errdetail("Expected \",\" or \"]\", but found \"%s\".",
1186 token),
1187 report_json_context(lex)));
1188 break;
1189 case JSON_PARSE_OBJECT_START:
1190 ereport(ERROR,
1191 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
1192 errmsg("invalid input syntax for type %s", "json"),
1193 errdetail("Expected string or \"}\", but found \"%s\".",
1194 token),
1195 report_json_context(lex)));
1196 break;
1197 case JSON_PARSE_OBJECT_LABEL:
1198 ereport(ERROR,
1199 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
1200 errmsg("invalid input syntax for type %s", "json"),
1201 errdetail("Expected \":\", but found \"%s\".",
1202 token),
1203 report_json_context(lex)));
1204 break;
1205 case JSON_PARSE_OBJECT_NEXT:
1206 ereport(ERROR,
1207 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
1208 errmsg("invalid input syntax for type %s", "json"),
1209 errdetail("Expected \",\" or \"}\", but found \"%s\".",
1210 token),
1211 report_json_context(lex)));
1212 break;
1213 case JSON_PARSE_OBJECT_COMMA:
1214 ereport(ERROR,
1215 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
1216 errmsg("invalid input syntax for type %s", "json"),
1217 errdetail("Expected string, but found \"%s\".",
1218 token),
1219 report_json_context(lex)));
1220 break;
1221 default:
1222 elog(ERROR, "unexpected json parse state: %d", ctx);
1223 }
1224 }
1225 }
1226
1227 /*
1228 * Report an invalid input token.
1229 *
1230 * lex->token_start and lex->token_terminator must identify the token.
1231 */
1232 static void
report_invalid_token(JsonLexContext * lex)1233 report_invalid_token(JsonLexContext *lex)
1234 {
1235 char *token;
1236 int toklen;
1237
1238 /* Separate out the offending token. */
1239 toklen = lex->token_terminator - lex->token_start;
1240 token = palloc(toklen + 1);
1241 memcpy(token, lex->token_start, toklen);
1242 token[toklen] = '\0';
1243
1244 ereport(ERROR,
1245 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
1246 errmsg("invalid input syntax for type %s", "json"),
1247 errdetail("Token \"%s\" is invalid.", token),
1248 report_json_context(lex)));
1249 }
1250
1251 /*
1252 * Report a CONTEXT line for bogus JSON input.
1253 *
1254 * lex->token_terminator must be set to identify the spot where we detected
1255 * the error. Note that lex->token_start might be NULL, in case we recognized
1256 * error at EOF.
1257 *
1258 * The return value isn't meaningful, but we make it non-void so that this
1259 * can be invoked inside ereport().
1260 */
1261 static int
report_json_context(JsonLexContext * lex)1262 report_json_context(JsonLexContext *lex)
1263 {
1264 const char *context_start;
1265 const char *context_end;
1266 const char *line_start;
1267 int line_number;
1268 char *ctxt;
1269 int ctxtlen;
1270 const char *prefix;
1271 const char *suffix;
1272
1273 /* Choose boundaries for the part of the input we will display */
1274 context_start = lex->input;
1275 context_end = lex->token_terminator;
1276 line_start = context_start;
1277 line_number = 1;
1278 for (;;)
1279 {
1280 /* Always advance over newlines */
1281 if (context_start < context_end && *context_start == '\n')
1282 {
1283 context_start++;
1284 line_start = context_start;
1285 line_number++;
1286 continue;
1287 }
1288 /* Otherwise, done as soon as we are close enough to context_end */
1289 if (context_end - context_start < 50)
1290 break;
1291 /* Advance to next multibyte character */
1292 if (IS_HIGHBIT_SET(*context_start))
1293 context_start += pg_mblen(context_start);
1294 else
1295 context_start++;
1296 }
1297
1298 /*
1299 * We add "..." to indicate that the excerpt doesn't start at the
1300 * beginning of the line ... but if we're within 3 characters of the
1301 * beginning of the line, we might as well just show the whole line.
1302 */
1303 if (context_start - line_start <= 3)
1304 context_start = line_start;
1305
1306 /* Get a null-terminated copy of the data to present */
1307 ctxtlen = context_end - context_start;
1308 ctxt = palloc(ctxtlen + 1);
1309 memcpy(ctxt, context_start, ctxtlen);
1310 ctxt[ctxtlen] = '\0';
1311
1312 /*
1313 * Show the context, prefixing "..." if not starting at start of line, and
1314 * suffixing "..." if not ending at end of line.
1315 */
1316 prefix = (context_start > line_start) ? "..." : "";
1317 suffix = (lex->token_type != JSON_TOKEN_END && context_end - lex->input < lex->input_length && *context_end != '\n' && *context_end != '\r') ? "..." : "";
1318
1319 return errcontext("JSON data, line %d: %s%s%s",
1320 line_number, prefix, ctxt, suffix);
1321 }
1322
1323 /*
1324 * Extract a single, possibly multi-byte char from the input string.
1325 */
1326 static char *
extract_mb_char(char * s)1327 extract_mb_char(char *s)
1328 {
1329 char *res;
1330 int len;
1331
1332 len = pg_mblen(s);
1333 res = palloc(len + 1);
1334 memcpy(res, s, len);
1335 res[len] = '\0';
1336
1337 return res;
1338 }
1339
1340 /*
1341 * Determine how we want to print values of a given type in datum_to_json.
1342 *
1343 * Given the datatype OID, return its JsonTypeCategory, as well as the type's
1344 * output function OID. If the returned category is JSONTYPE_CAST, we
1345 * return the OID of the type->JSON cast function instead.
1346 */
1347 static void
json_categorize_type(Oid typoid,JsonTypeCategory * tcategory,Oid * outfuncoid)1348 json_categorize_type(Oid typoid,
1349 JsonTypeCategory *tcategory,
1350 Oid *outfuncoid)
1351 {
1352 bool typisvarlena;
1353
1354 /* Look through any domain */
1355 typoid = getBaseType(typoid);
1356
1357 *outfuncoid = InvalidOid;
1358
1359 /*
1360 * We need to get the output function for everything except date and
1361 * timestamp types, array and composite types, booleans, and non-builtin
1362 * types where there's a cast to json.
1363 */
1364
1365 switch (typoid)
1366 {
1367 case BOOLOID:
1368 *tcategory = JSONTYPE_BOOL;
1369 break;
1370
1371 case INT2OID:
1372 case INT4OID:
1373 case INT8OID:
1374 case FLOAT4OID:
1375 case FLOAT8OID:
1376 case NUMERICOID:
1377 getTypeOutputInfo(typoid, outfuncoid, &typisvarlena);
1378 *tcategory = JSONTYPE_NUMERIC;
1379 break;
1380
1381 case DATEOID:
1382 *tcategory = JSONTYPE_DATE;
1383 break;
1384
1385 case TIMESTAMPOID:
1386 *tcategory = JSONTYPE_TIMESTAMP;
1387 break;
1388
1389 case TIMESTAMPTZOID:
1390 *tcategory = JSONTYPE_TIMESTAMPTZ;
1391 break;
1392
1393 case JSONOID:
1394 case JSONBOID:
1395 getTypeOutputInfo(typoid, outfuncoid, &typisvarlena);
1396 *tcategory = JSONTYPE_JSON;
1397 break;
1398
1399 default:
1400 /* Check for arrays and composites */
1401 if (OidIsValid(get_element_type(typoid)) || typoid == ANYARRAYOID
1402 || typoid == RECORDARRAYOID)
1403 *tcategory = JSONTYPE_ARRAY;
1404 else if (type_is_rowtype(typoid)) /* includes RECORDOID */
1405 *tcategory = JSONTYPE_COMPOSITE;
1406 else
1407 {
1408 /* It's probably the general case ... */
1409 *tcategory = JSONTYPE_OTHER;
1410 /* but let's look for a cast to json, if it's not built-in */
1411 if (typoid >= FirstNormalObjectId)
1412 {
1413 Oid castfunc;
1414 CoercionPathType ctype;
1415
1416 ctype = find_coercion_pathway(JSONOID, typoid,
1417 COERCION_EXPLICIT,
1418 &castfunc);
1419 if (ctype == COERCION_PATH_FUNC && OidIsValid(castfunc))
1420 {
1421 *tcategory = JSONTYPE_CAST;
1422 *outfuncoid = castfunc;
1423 }
1424 else
1425 {
1426 /* non builtin type with no cast */
1427 getTypeOutputInfo(typoid, outfuncoid, &typisvarlena);
1428 }
1429 }
1430 else
1431 {
1432 /* any other builtin type */
1433 getTypeOutputInfo(typoid, outfuncoid, &typisvarlena);
1434 }
1435 }
1436 break;
1437 }
1438 }
1439
1440 /*
1441 * Turn a Datum into JSON text, appending the string to "result".
1442 *
1443 * tcategory and outfuncoid are from a previous call to json_categorize_type,
1444 * except that if is_null is true then they can be invalid.
1445 *
1446 * If key_scalar is true, the value is being printed as a key, so insist
1447 * it's of an acceptable type, and force it to be quoted.
1448 */
1449 static void
datum_to_json(Datum val,bool is_null,StringInfo result,JsonTypeCategory tcategory,Oid outfuncoid,bool key_scalar)1450 datum_to_json(Datum val, bool is_null, StringInfo result,
1451 JsonTypeCategory tcategory, Oid outfuncoid,
1452 bool key_scalar)
1453 {
1454 char *outputstr;
1455 text *jsontext;
1456
1457 check_stack_depth();
1458
1459 /* callers are expected to ensure that null keys are not passed in */
1460 Assert(!(key_scalar && is_null));
1461
1462 if (is_null)
1463 {
1464 appendStringInfoString(result, "null");
1465 return;
1466 }
1467
1468 if (key_scalar &&
1469 (tcategory == JSONTYPE_ARRAY ||
1470 tcategory == JSONTYPE_COMPOSITE ||
1471 tcategory == JSONTYPE_JSON ||
1472 tcategory == JSONTYPE_CAST))
1473 ereport(ERROR,
1474 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
1475 errmsg("key value must be scalar, not array, composite, or json")));
1476
1477 switch (tcategory)
1478 {
1479 case JSONTYPE_ARRAY:
1480 array_to_json_internal(val, result, false);
1481 break;
1482 case JSONTYPE_COMPOSITE:
1483 composite_to_json(val, result, false);
1484 break;
1485 case JSONTYPE_BOOL:
1486 outputstr = DatumGetBool(val) ? "true" : "false";
1487 if (key_scalar)
1488 escape_json(result, outputstr);
1489 else
1490 appendStringInfoString(result, outputstr);
1491 break;
1492 case JSONTYPE_NUMERIC:
1493 outputstr = OidOutputFunctionCall(outfuncoid, val);
1494
1495 /*
1496 * Don't call escape_json for a non-key if it's a valid JSON
1497 * number.
1498 */
1499 if (!key_scalar && IsValidJsonNumber(outputstr, strlen(outputstr)))
1500 appendStringInfoString(result, outputstr);
1501 else
1502 escape_json(result, outputstr);
1503 pfree(outputstr);
1504 break;
1505 case JSONTYPE_DATE:
1506 {
1507 DateADT date;
1508 struct pg_tm tm;
1509 char buf[MAXDATELEN + 1];
1510
1511 date = DatumGetDateADT(val);
1512 /* Same as date_out(), but forcing DateStyle */
1513 if (DATE_NOT_FINITE(date))
1514 EncodeSpecialDate(date, buf);
1515 else
1516 {
1517 j2date(date + POSTGRES_EPOCH_JDATE,
1518 &(tm.tm_year), &(tm.tm_mon), &(tm.tm_mday));
1519 EncodeDateOnly(&tm, USE_XSD_DATES, buf);
1520 }
1521 appendStringInfo(result, "\"%s\"", buf);
1522 }
1523 break;
1524 case JSONTYPE_TIMESTAMP:
1525 {
1526 Timestamp timestamp;
1527 struct pg_tm tm;
1528 fsec_t fsec;
1529 char buf[MAXDATELEN + 1];
1530
1531 timestamp = DatumGetTimestamp(val);
1532 /* Same as timestamp_out(), but forcing DateStyle */
1533 if (TIMESTAMP_NOT_FINITE(timestamp))
1534 EncodeSpecialTimestamp(timestamp, buf);
1535 else if (timestamp2tm(timestamp, NULL, &tm, &fsec, NULL, NULL) == 0)
1536 EncodeDateTime(&tm, fsec, false, 0, NULL, USE_XSD_DATES, buf);
1537 else
1538 ereport(ERROR,
1539 (errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
1540 errmsg("timestamp out of range")));
1541 appendStringInfo(result, "\"%s\"", buf);
1542 }
1543 break;
1544 case JSONTYPE_TIMESTAMPTZ:
1545 {
1546 TimestampTz timestamp;
1547 struct pg_tm tm;
1548 int tz;
1549 fsec_t fsec;
1550 const char *tzn = NULL;
1551 char buf[MAXDATELEN + 1];
1552
1553 timestamp = DatumGetTimestampTz(val);
1554 /* Same as timestamptz_out(), but forcing DateStyle */
1555 if (TIMESTAMP_NOT_FINITE(timestamp))
1556 EncodeSpecialTimestamp(timestamp, buf);
1557 else if (timestamp2tm(timestamp, &tz, &tm, &fsec, &tzn, NULL) == 0)
1558 EncodeDateTime(&tm, fsec, true, tz, tzn, USE_XSD_DATES, buf);
1559 else
1560 ereport(ERROR,
1561 (errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
1562 errmsg("timestamp out of range")));
1563 appendStringInfo(result, "\"%s\"", buf);
1564 }
1565 break;
1566 case JSONTYPE_JSON:
1567 /* JSON and JSONB output will already be escaped */
1568 outputstr = OidOutputFunctionCall(outfuncoid, val);
1569 appendStringInfoString(result, outputstr);
1570 pfree(outputstr);
1571 break;
1572 case JSONTYPE_CAST:
1573 /* outfuncoid refers to a cast function, not an output function */
1574 jsontext = DatumGetTextPP(OidFunctionCall1(outfuncoid, val));
1575 outputstr = text_to_cstring(jsontext);
1576 appendStringInfoString(result, outputstr);
1577 pfree(outputstr);
1578 pfree(jsontext);
1579 break;
1580 default:
1581 outputstr = OidOutputFunctionCall(outfuncoid, val);
1582 escape_json(result, outputstr);
1583 pfree(outputstr);
1584 break;
1585 }
1586 }
1587
1588 /*
1589 * Process a single dimension of an array.
1590 * If it's the innermost dimension, output the values, otherwise call
1591 * ourselves recursively to process the next dimension.
1592 */
1593 static void
array_dim_to_json(StringInfo result,int dim,int ndims,int * dims,Datum * vals,bool * nulls,int * valcount,JsonTypeCategory tcategory,Oid outfuncoid,bool use_line_feeds)1594 array_dim_to_json(StringInfo result, int dim, int ndims, int *dims, Datum *vals,
1595 bool *nulls, int *valcount, JsonTypeCategory tcategory,
1596 Oid outfuncoid, bool use_line_feeds)
1597 {
1598 int i;
1599 const char *sep;
1600
1601 Assert(dim < ndims);
1602
1603 sep = use_line_feeds ? ",\n " : ",";
1604
1605 appendStringInfoChar(result, '[');
1606
1607 for (i = 1; i <= dims[dim]; i++)
1608 {
1609 if (i > 1)
1610 appendStringInfoString(result, sep);
1611
1612 if (dim + 1 == ndims)
1613 {
1614 datum_to_json(vals[*valcount], nulls[*valcount], result, tcategory,
1615 outfuncoid, false);
1616 (*valcount)++;
1617 }
1618 else
1619 {
1620 /*
1621 * Do we want line feeds on inner dimensions of arrays? For now
1622 * we'll say no.
1623 */
1624 array_dim_to_json(result, dim + 1, ndims, dims, vals, nulls,
1625 valcount, tcategory, outfuncoid, false);
1626 }
1627 }
1628
1629 appendStringInfoChar(result, ']');
1630 }
1631
1632 /*
1633 * Turn an array into JSON.
1634 */
1635 static void
array_to_json_internal(Datum array,StringInfo result,bool use_line_feeds)1636 array_to_json_internal(Datum array, StringInfo result, bool use_line_feeds)
1637 {
1638 ArrayType *v = DatumGetArrayTypeP(array);
1639 Oid element_type = ARR_ELEMTYPE(v);
1640 int *dim;
1641 int ndim;
1642 int nitems;
1643 int count = 0;
1644 Datum *elements;
1645 bool *nulls;
1646 int16 typlen;
1647 bool typbyval;
1648 char typalign;
1649 JsonTypeCategory tcategory;
1650 Oid outfuncoid;
1651
1652 ndim = ARR_NDIM(v);
1653 dim = ARR_DIMS(v);
1654 nitems = ArrayGetNItems(ndim, dim);
1655
1656 if (nitems <= 0)
1657 {
1658 appendStringInfoString(result, "[]");
1659 return;
1660 }
1661
1662 get_typlenbyvalalign(element_type,
1663 &typlen, &typbyval, &typalign);
1664
1665 json_categorize_type(element_type,
1666 &tcategory, &outfuncoid);
1667
1668 deconstruct_array(v, element_type, typlen, typbyval,
1669 typalign, &elements, &nulls,
1670 &nitems);
1671
1672 array_dim_to_json(result, 0, ndim, dim, elements, nulls, &count, tcategory,
1673 outfuncoid, use_line_feeds);
1674
1675 pfree(elements);
1676 pfree(nulls);
1677 }
1678
1679 /*
1680 * Turn a composite / record into JSON.
1681 */
1682 static void
composite_to_json(Datum composite,StringInfo result,bool use_line_feeds)1683 composite_to_json(Datum composite, StringInfo result, bool use_line_feeds)
1684 {
1685 HeapTupleHeader td;
1686 Oid tupType;
1687 int32 tupTypmod;
1688 TupleDesc tupdesc;
1689 HeapTupleData tmptup,
1690 *tuple;
1691 int i;
1692 bool needsep = false;
1693 const char *sep;
1694
1695 sep = use_line_feeds ? ",\n " : ",";
1696
1697 td = DatumGetHeapTupleHeader(composite);
1698
1699 /* Extract rowtype info and find a tupdesc */
1700 tupType = HeapTupleHeaderGetTypeId(td);
1701 tupTypmod = HeapTupleHeaderGetTypMod(td);
1702 tupdesc = lookup_rowtype_tupdesc(tupType, tupTypmod);
1703
1704 /* Build a temporary HeapTuple control structure */
1705 tmptup.t_len = HeapTupleHeaderGetDatumLength(td);
1706 tmptup.t_data = td;
1707 tuple = &tmptup;
1708
1709 appendStringInfoChar(result, '{');
1710
1711 for (i = 0; i < tupdesc->natts; i++)
1712 {
1713 Datum val;
1714 bool isnull;
1715 char *attname;
1716 JsonTypeCategory tcategory;
1717 Oid outfuncoid;
1718
1719 if (tupdesc->attrs[i]->attisdropped)
1720 continue;
1721
1722 if (needsep)
1723 appendStringInfoString(result, sep);
1724 needsep = true;
1725
1726 attname = NameStr(tupdesc->attrs[i]->attname);
1727 escape_json(result, attname);
1728 appendStringInfoChar(result, ':');
1729
1730 val = heap_getattr(tuple, i + 1, tupdesc, &isnull);
1731
1732 if (isnull)
1733 {
1734 tcategory = JSONTYPE_NULL;
1735 outfuncoid = InvalidOid;
1736 }
1737 else
1738 json_categorize_type(tupdesc->attrs[i]->atttypid,
1739 &tcategory, &outfuncoid);
1740
1741 datum_to_json(val, isnull, result, tcategory, outfuncoid, false);
1742 }
1743
1744 appendStringInfoChar(result, '}');
1745 ReleaseTupleDesc(tupdesc);
1746 }
1747
1748 /*
1749 * Append JSON text for "val" to "result".
1750 *
1751 * This is just a thin wrapper around datum_to_json. If the same type will be
1752 * printed many times, avoid using this; better to do the json_categorize_type
1753 * lookups only once.
1754 */
1755 static void
add_json(Datum val,bool is_null,StringInfo result,Oid val_type,bool key_scalar)1756 add_json(Datum val, bool is_null, StringInfo result,
1757 Oid val_type, bool key_scalar)
1758 {
1759 JsonTypeCategory tcategory;
1760 Oid outfuncoid;
1761
1762 if (val_type == InvalidOid)
1763 ereport(ERROR,
1764 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
1765 errmsg("could not determine input data type")));
1766
1767 if (is_null)
1768 {
1769 tcategory = JSONTYPE_NULL;
1770 outfuncoid = InvalidOid;
1771 }
1772 else
1773 json_categorize_type(val_type,
1774 &tcategory, &outfuncoid);
1775
1776 datum_to_json(val, is_null, result, tcategory, outfuncoid, key_scalar);
1777 }
1778
1779 /*
1780 * SQL function array_to_json(row)
1781 */
1782 extern Datum
array_to_json(PG_FUNCTION_ARGS)1783 array_to_json(PG_FUNCTION_ARGS)
1784 {
1785 Datum array = PG_GETARG_DATUM(0);
1786 StringInfo result;
1787
1788 result = makeStringInfo();
1789
1790 array_to_json_internal(array, result, false);
1791
1792 PG_RETURN_TEXT_P(cstring_to_text_with_len(result->data, result->len));
1793 }
1794
1795 /*
1796 * SQL function array_to_json(row, prettybool)
1797 */
1798 extern Datum
array_to_json_pretty(PG_FUNCTION_ARGS)1799 array_to_json_pretty(PG_FUNCTION_ARGS)
1800 {
1801 Datum array = PG_GETARG_DATUM(0);
1802 bool use_line_feeds = PG_GETARG_BOOL(1);
1803 StringInfo result;
1804
1805 result = makeStringInfo();
1806
1807 array_to_json_internal(array, result, use_line_feeds);
1808
1809 PG_RETURN_TEXT_P(cstring_to_text_with_len(result->data, result->len));
1810 }
1811
1812 /*
1813 * SQL function row_to_json(row)
1814 */
1815 extern Datum
row_to_json(PG_FUNCTION_ARGS)1816 row_to_json(PG_FUNCTION_ARGS)
1817 {
1818 Datum array = PG_GETARG_DATUM(0);
1819 StringInfo result;
1820
1821 result = makeStringInfo();
1822
1823 composite_to_json(array, result, false);
1824
1825 PG_RETURN_TEXT_P(cstring_to_text_with_len(result->data, result->len));
1826 }
1827
1828 /*
1829 * SQL function row_to_json(row, prettybool)
1830 */
1831 extern Datum
row_to_json_pretty(PG_FUNCTION_ARGS)1832 row_to_json_pretty(PG_FUNCTION_ARGS)
1833 {
1834 Datum array = PG_GETARG_DATUM(0);
1835 bool use_line_feeds = PG_GETARG_BOOL(1);
1836 StringInfo result;
1837
1838 result = makeStringInfo();
1839
1840 composite_to_json(array, result, use_line_feeds);
1841
1842 PG_RETURN_TEXT_P(cstring_to_text_with_len(result->data, result->len));
1843 }
1844
1845 /*
1846 * SQL function to_json(anyvalue)
1847 */
1848 Datum
to_json(PG_FUNCTION_ARGS)1849 to_json(PG_FUNCTION_ARGS)
1850 {
1851 Datum val = PG_GETARG_DATUM(0);
1852 Oid val_type = get_fn_expr_argtype(fcinfo->flinfo, 0);
1853 StringInfo result;
1854 JsonTypeCategory tcategory;
1855 Oid outfuncoid;
1856
1857 if (val_type == InvalidOid)
1858 ereport(ERROR,
1859 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
1860 errmsg("could not determine input data type")));
1861
1862 json_categorize_type(val_type,
1863 &tcategory, &outfuncoid);
1864
1865 result = makeStringInfo();
1866
1867 datum_to_json(val, false, result, tcategory, outfuncoid, false);
1868
1869 PG_RETURN_TEXT_P(cstring_to_text_with_len(result->data, result->len));
1870 }
1871
1872 /*
1873 * json_agg transition function
1874 *
1875 * aggregate input column as a json array value.
1876 */
1877 Datum
json_agg_transfn(PG_FUNCTION_ARGS)1878 json_agg_transfn(PG_FUNCTION_ARGS)
1879 {
1880 MemoryContext aggcontext,
1881 oldcontext;
1882 JsonAggState *state;
1883 Datum val;
1884
1885 if (!AggCheckCallContext(fcinfo, &aggcontext))
1886 {
1887 /* cannot be called directly because of internal-type argument */
1888 elog(ERROR, "json_agg_transfn called in non-aggregate context");
1889 }
1890
1891 if (PG_ARGISNULL(0))
1892 {
1893 Oid arg_type = get_fn_expr_argtype(fcinfo->flinfo, 1);
1894
1895 if (arg_type == InvalidOid)
1896 ereport(ERROR,
1897 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
1898 errmsg("could not determine input data type")));
1899
1900 /*
1901 * Make this state object in a context where it will persist for the
1902 * duration of the aggregate call. MemoryContextSwitchTo is only
1903 * needed the first time, as the StringInfo routines make sure they
1904 * use the right context to enlarge the object if necessary.
1905 */
1906 oldcontext = MemoryContextSwitchTo(aggcontext);
1907 state = (JsonAggState *) palloc(sizeof(JsonAggState));
1908 state->str = makeStringInfo();
1909 MemoryContextSwitchTo(oldcontext);
1910
1911 appendStringInfoChar(state->str, '[');
1912 json_categorize_type(arg_type, &state->val_category,
1913 &state->val_output_func);
1914 }
1915 else
1916 {
1917 state = (JsonAggState *) PG_GETARG_POINTER(0);
1918 appendStringInfoString(state->str, ", ");
1919 }
1920
1921 /* fast path for NULLs */
1922 if (PG_ARGISNULL(1))
1923 {
1924 datum_to_json((Datum) 0, true, state->str, JSONTYPE_NULL,
1925 InvalidOid, false);
1926 PG_RETURN_POINTER(state);
1927 }
1928
1929 val = PG_GETARG_DATUM(1);
1930
1931 /* add some whitespace if structured type and not first item */
1932 if (!PG_ARGISNULL(0) &&
1933 (state->val_category == JSONTYPE_ARRAY ||
1934 state->val_category == JSONTYPE_COMPOSITE))
1935 {
1936 appendStringInfoString(state->str, "\n ");
1937 }
1938
1939 datum_to_json(val, false, state->str, state->val_category,
1940 state->val_output_func, false);
1941
1942 /*
1943 * The transition type for array_agg() is declared to be "internal", which
1944 * is a pass-by-value type the same size as a pointer. So we can safely
1945 * pass the JsonAggState pointer through nodeAgg.c's machinations.
1946 */
1947 PG_RETURN_POINTER(state);
1948 }
1949
1950 /*
1951 * json_agg final function
1952 */
1953 Datum
json_agg_finalfn(PG_FUNCTION_ARGS)1954 json_agg_finalfn(PG_FUNCTION_ARGS)
1955 {
1956 JsonAggState *state;
1957
1958 /* cannot be called directly because of internal-type argument */
1959 Assert(AggCheckCallContext(fcinfo, NULL));
1960
1961 state = PG_ARGISNULL(0) ?
1962 NULL :
1963 (JsonAggState *) PG_GETARG_POINTER(0);
1964
1965 /* NULL result for no rows in, as is standard with aggregates */
1966 if (state == NULL)
1967 PG_RETURN_NULL();
1968
1969 /* Else return state with appropriate array terminator added */
1970 PG_RETURN_TEXT_P(catenate_stringinfo_string(state->str, "]"));
1971 }
1972
1973 /*
1974 * json_object_agg transition function.
1975 *
1976 * aggregate two input columns as a single json object value.
1977 */
1978 Datum
json_object_agg_transfn(PG_FUNCTION_ARGS)1979 json_object_agg_transfn(PG_FUNCTION_ARGS)
1980 {
1981 MemoryContext aggcontext,
1982 oldcontext;
1983 JsonAggState *state;
1984 Datum arg;
1985
1986 if (!AggCheckCallContext(fcinfo, &aggcontext))
1987 {
1988 /* cannot be called directly because of internal-type argument */
1989 elog(ERROR, "json_object_agg_transfn called in non-aggregate context");
1990 }
1991
1992 if (PG_ARGISNULL(0))
1993 {
1994 Oid arg_type;
1995
1996 /*
1997 * Make the StringInfo in a context where it will persist for the
1998 * duration of the aggregate call. Switching context is only needed
1999 * for this initial step, as the StringInfo routines make sure they
2000 * use the right context to enlarge the object if necessary.
2001 */
2002 oldcontext = MemoryContextSwitchTo(aggcontext);
2003 state = (JsonAggState *) palloc(sizeof(JsonAggState));
2004 state->str = makeStringInfo();
2005 MemoryContextSwitchTo(oldcontext);
2006
2007 arg_type = get_fn_expr_argtype(fcinfo->flinfo, 1);
2008
2009 if (arg_type == InvalidOid)
2010 ereport(ERROR,
2011 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
2012 errmsg("could not determine data type for argument %d", 1)));
2013
2014 json_categorize_type(arg_type, &state->key_category,
2015 &state->key_output_func);
2016
2017 arg_type = get_fn_expr_argtype(fcinfo->flinfo, 2);
2018
2019 if (arg_type == InvalidOid)
2020 ereport(ERROR,
2021 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
2022 errmsg("could not determine data type for argument %d", 2)));
2023
2024 json_categorize_type(arg_type, &state->val_category,
2025 &state->val_output_func);
2026
2027 appendStringInfoString(state->str, "{ ");
2028 }
2029 else
2030 {
2031 state = (JsonAggState *) PG_GETARG_POINTER(0);
2032 appendStringInfoString(state->str, ", ");
2033 }
2034
2035 /*
2036 * Note: since json_object_agg() is declared as taking type "any", the
2037 * parser will not do any type conversion on unknown-type literals (that
2038 * is, undecorated strings or NULLs). Such values will arrive here as
2039 * type UNKNOWN, which fortunately does not matter to us, since
2040 * unknownout() works fine.
2041 */
2042
2043 if (PG_ARGISNULL(1))
2044 ereport(ERROR,
2045 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
2046 errmsg("field name must not be null")));
2047
2048 arg = PG_GETARG_DATUM(1);
2049
2050 datum_to_json(arg, false, state->str, state->key_category,
2051 state->key_output_func, true);
2052
2053 appendStringInfoString(state->str, " : ");
2054
2055 if (PG_ARGISNULL(2))
2056 arg = (Datum) 0;
2057 else
2058 arg = PG_GETARG_DATUM(2);
2059
2060 datum_to_json(arg, PG_ARGISNULL(2), state->str, state->val_category,
2061 state->val_output_func, false);
2062
2063 PG_RETURN_POINTER(state);
2064 }
2065
2066 /*
2067 * json_object_agg final function.
2068 */
2069 Datum
json_object_agg_finalfn(PG_FUNCTION_ARGS)2070 json_object_agg_finalfn(PG_FUNCTION_ARGS)
2071 {
2072 JsonAggState *state;
2073
2074 /* cannot be called directly because of internal-type argument */
2075 Assert(AggCheckCallContext(fcinfo, NULL));
2076
2077 state = PG_ARGISNULL(0) ? NULL : (JsonAggState *) PG_GETARG_POINTER(0);
2078
2079 /* NULL result for no rows in, as is standard with aggregates */
2080 if (state == NULL)
2081 PG_RETURN_NULL();
2082
2083 /* Else return state with appropriate object terminator added */
2084 PG_RETURN_TEXT_P(catenate_stringinfo_string(state->str, " }"));
2085 }
2086
2087 /*
2088 * Helper function for aggregates: return given StringInfo's contents plus
2089 * specified trailing string, as a text datum. We need this because aggregate
2090 * final functions are not allowed to modify the aggregate state.
2091 */
2092 static text *
catenate_stringinfo_string(StringInfo buffer,const char * addon)2093 catenate_stringinfo_string(StringInfo buffer, const char *addon)
2094 {
2095 /* custom version of cstring_to_text_with_len */
2096 int buflen = buffer->len;
2097 int addlen = strlen(addon);
2098 text *result = (text *) palloc(buflen + addlen + VARHDRSZ);
2099
2100 SET_VARSIZE(result, buflen + addlen + VARHDRSZ);
2101 memcpy(VARDATA(result), buffer->data, buflen);
2102 memcpy(VARDATA(result) + buflen, addon, addlen);
2103
2104 return result;
2105 }
2106
2107 /*
2108 * SQL function json_build_object(variadic "any")
2109 */
2110 Datum
json_build_object(PG_FUNCTION_ARGS)2111 json_build_object(PG_FUNCTION_ARGS)
2112 {
2113 int nargs = PG_NARGS();
2114 int i;
2115 const char *sep = "";
2116 StringInfo result;
2117 Datum *args;
2118 bool *nulls;
2119 Oid *types;
2120
2121 /* fetch argument values to build the object */
2122 nargs = extract_variadic_args(fcinfo, 0, false, &args, &types, &nulls);
2123
2124 if (nargs < 0)
2125 PG_RETURN_NULL();
2126
2127 if (nargs % 2 != 0)
2128 ereport(ERROR,
2129 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
2130 errmsg("argument list must have even number of elements"),
2131 errhint("The arguments of json_build_object() must consist of alternating keys and values.")));
2132
2133 result = makeStringInfo();
2134
2135 appendStringInfoChar(result, '{');
2136
2137 for (i = 0; i < nargs; i += 2)
2138 {
2139 appendStringInfoString(result, sep);
2140 sep = ", ";
2141
2142 /* process key */
2143 if (nulls[i])
2144 ereport(ERROR,
2145 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
2146 errmsg("argument %d cannot be null", i + 1),
2147 errhint("Object keys should be text.")));
2148
2149 add_json(args[i], false, result, types[i], true);
2150
2151 appendStringInfoString(result, " : ");
2152
2153 /* process value */
2154 add_json(args[i + 1], nulls[i + 1], result, types[i + 1], false);
2155 }
2156
2157 appendStringInfoChar(result, '}');
2158
2159 PG_RETURN_TEXT_P(cstring_to_text_with_len(result->data, result->len));
2160 }
2161
2162 /*
2163 * degenerate case of json_build_object where it gets 0 arguments.
2164 */
2165 Datum
json_build_object_noargs(PG_FUNCTION_ARGS)2166 json_build_object_noargs(PG_FUNCTION_ARGS)
2167 {
2168 PG_RETURN_TEXT_P(cstring_to_text_with_len("{}", 2));
2169 }
2170
2171 /*
2172 * SQL function json_build_array(variadic "any")
2173 */
2174 Datum
json_build_array(PG_FUNCTION_ARGS)2175 json_build_array(PG_FUNCTION_ARGS)
2176 {
2177 int nargs;
2178 int i;
2179 const char *sep = "";
2180 StringInfo result;
2181 Datum *args;
2182 bool *nulls;
2183 Oid *types;
2184
2185 /* fetch argument values to build the array */
2186 nargs = extract_variadic_args(fcinfo, 0, false, &args, &types, &nulls);
2187
2188 if (nargs < 0)
2189 PG_RETURN_NULL();
2190
2191 result = makeStringInfo();
2192
2193 appendStringInfoChar(result, '[');
2194
2195 for (i = 0; i < nargs; i++)
2196 {
2197 appendStringInfoString(result, sep);
2198 sep = ", ";
2199 add_json(args[i], nulls[i], result, types[i], false);
2200 }
2201
2202 appendStringInfoChar(result, ']');
2203
2204 PG_RETURN_TEXT_P(cstring_to_text_with_len(result->data, result->len));
2205 }
2206
2207 /*
2208 * degenerate case of json_build_array where it gets 0 arguments.
2209 */
2210 Datum
json_build_array_noargs(PG_FUNCTION_ARGS)2211 json_build_array_noargs(PG_FUNCTION_ARGS)
2212 {
2213 PG_RETURN_TEXT_P(cstring_to_text_with_len("[]", 2));
2214 }
2215
2216 /*
2217 * SQL function json_object(text[])
2218 *
2219 * take a one or two dimensional array of text as key/value pairs
2220 * for a json object.
2221 */
2222 Datum
json_object(PG_FUNCTION_ARGS)2223 json_object(PG_FUNCTION_ARGS)
2224 {
2225 ArrayType *in_array = PG_GETARG_ARRAYTYPE_P(0);
2226 int ndims = ARR_NDIM(in_array);
2227 StringInfoData result;
2228 Datum *in_datums;
2229 bool *in_nulls;
2230 int in_count,
2231 count,
2232 i;
2233 text *rval;
2234 char *v;
2235
2236 switch (ndims)
2237 {
2238 case 0:
2239 PG_RETURN_DATUM(CStringGetTextDatum("{}"));
2240 break;
2241
2242 case 1:
2243 if ((ARR_DIMS(in_array)[0]) % 2)
2244 ereport(ERROR,
2245 (errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
2246 errmsg("array must have even number of elements")));
2247 break;
2248
2249 case 2:
2250 if ((ARR_DIMS(in_array)[1]) != 2)
2251 ereport(ERROR,
2252 (errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
2253 errmsg("array must have two columns")));
2254 break;
2255
2256 default:
2257 ereport(ERROR,
2258 (errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
2259 errmsg("wrong number of array subscripts")));
2260 }
2261
2262 deconstruct_array(in_array,
2263 TEXTOID, -1, false, 'i',
2264 &in_datums, &in_nulls, &in_count);
2265
2266 count = in_count / 2;
2267
2268 initStringInfo(&result);
2269
2270 appendStringInfoChar(&result, '{');
2271
2272 for (i = 0; i < count; ++i)
2273 {
2274 if (in_nulls[i * 2])
2275 ereport(ERROR,
2276 (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
2277 errmsg("null value not allowed for object key")));
2278
2279 v = TextDatumGetCString(in_datums[i * 2]);
2280 if (i > 0)
2281 appendStringInfoString(&result, ", ");
2282 escape_json(&result, v);
2283 appendStringInfoString(&result, " : ");
2284 pfree(v);
2285 if (in_nulls[i * 2 + 1])
2286 appendStringInfoString(&result, "null");
2287 else
2288 {
2289 v = TextDatumGetCString(in_datums[i * 2 + 1]);
2290 escape_json(&result, v);
2291 pfree(v);
2292 }
2293 }
2294
2295 appendStringInfoChar(&result, '}');
2296
2297 pfree(in_datums);
2298 pfree(in_nulls);
2299
2300 rval = cstring_to_text_with_len(result.data, result.len);
2301 pfree(result.data);
2302
2303 PG_RETURN_TEXT_P(rval);
2304
2305 }
2306
2307 /*
2308 * SQL function json_object(text[], text[])
2309 *
2310 * take separate key and value arrays of text to construct a json object
2311 * pairwise.
2312 */
2313 Datum
json_object_two_arg(PG_FUNCTION_ARGS)2314 json_object_two_arg(PG_FUNCTION_ARGS)
2315 {
2316 ArrayType *key_array = PG_GETARG_ARRAYTYPE_P(0);
2317 ArrayType *val_array = PG_GETARG_ARRAYTYPE_P(1);
2318 int nkdims = ARR_NDIM(key_array);
2319 int nvdims = ARR_NDIM(val_array);
2320 StringInfoData result;
2321 Datum *key_datums,
2322 *val_datums;
2323 bool *key_nulls,
2324 *val_nulls;
2325 int key_count,
2326 val_count,
2327 i;
2328 text *rval;
2329 char *v;
2330
2331 if (nkdims > 1 || nkdims != nvdims)
2332 ereport(ERROR,
2333 (errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
2334 errmsg("wrong number of array subscripts")));
2335
2336 if (nkdims == 0)
2337 PG_RETURN_DATUM(CStringGetTextDatum("{}"));
2338
2339 deconstruct_array(key_array,
2340 TEXTOID, -1, false, 'i',
2341 &key_datums, &key_nulls, &key_count);
2342
2343 deconstruct_array(val_array,
2344 TEXTOID, -1, false, 'i',
2345 &val_datums, &val_nulls, &val_count);
2346
2347 if (key_count != val_count)
2348 ereport(ERROR,
2349 (errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
2350 errmsg("mismatched array dimensions")));
2351
2352 initStringInfo(&result);
2353
2354 appendStringInfoChar(&result, '{');
2355
2356 for (i = 0; i < key_count; ++i)
2357 {
2358 if (key_nulls[i])
2359 ereport(ERROR,
2360 (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
2361 errmsg("null value not allowed for object key")));
2362
2363 v = TextDatumGetCString(key_datums[i]);
2364 if (i > 0)
2365 appendStringInfoString(&result, ", ");
2366 escape_json(&result, v);
2367 appendStringInfoString(&result, " : ");
2368 pfree(v);
2369 if (val_nulls[i])
2370 appendStringInfoString(&result, "null");
2371 else
2372 {
2373 v = TextDatumGetCString(val_datums[i]);
2374 escape_json(&result, v);
2375 pfree(v);
2376 }
2377 }
2378
2379 appendStringInfoChar(&result, '}');
2380
2381 pfree(key_datums);
2382 pfree(key_nulls);
2383 pfree(val_datums);
2384 pfree(val_nulls);
2385
2386 rval = cstring_to_text_with_len(result.data, result.len);
2387 pfree(result.data);
2388
2389 PG_RETURN_TEXT_P(rval);
2390 }
2391
2392
2393 /*
2394 * Produce a JSON string literal, properly escaping characters in the text.
2395 */
2396 void
escape_json(StringInfo buf,const char * str)2397 escape_json(StringInfo buf, const char *str)
2398 {
2399 const char *p;
2400
2401 appendStringInfoCharMacro(buf, '"');
2402 for (p = str; *p; p++)
2403 {
2404 switch (*p)
2405 {
2406 case '\b':
2407 appendStringInfoString(buf, "\\b");
2408 break;
2409 case '\f':
2410 appendStringInfoString(buf, "\\f");
2411 break;
2412 case '\n':
2413 appendStringInfoString(buf, "\\n");
2414 break;
2415 case '\r':
2416 appendStringInfoString(buf, "\\r");
2417 break;
2418 case '\t':
2419 appendStringInfoString(buf, "\\t");
2420 break;
2421 case '"':
2422 appendStringInfoString(buf, "\\\"");
2423 break;
2424 case '\\':
2425 appendStringInfoString(buf, "\\\\");
2426 break;
2427 default:
2428 if ((unsigned char) *p < ' ')
2429 appendStringInfo(buf, "\\u%04x", (int) *p);
2430 else
2431 appendStringInfoCharMacro(buf, *p);
2432 break;
2433 }
2434 }
2435 appendStringInfoCharMacro(buf, '"');
2436 }
2437
2438 /*
2439 * SQL function json_typeof(json) -> text
2440 *
2441 * Returns the type of the outermost JSON value as TEXT. Possible types are
2442 * "object", "array", "string", "number", "boolean", and "null".
2443 *
2444 * Performs a single call to json_lex() to get the first token of the supplied
2445 * value. This initial token uniquely determines the value's type. As our
2446 * input must already have been validated by json_in() or json_recv(), the
2447 * initial token should never be JSON_TOKEN_OBJECT_END, JSON_TOKEN_ARRAY_END,
2448 * JSON_TOKEN_COLON, JSON_TOKEN_COMMA, or JSON_TOKEN_END.
2449 */
2450 Datum
json_typeof(PG_FUNCTION_ARGS)2451 json_typeof(PG_FUNCTION_ARGS)
2452 {
2453 text *json;
2454
2455 JsonLexContext *lex;
2456 JsonTokenType tok;
2457 char *type;
2458
2459 json = PG_GETARG_TEXT_PP(0);
2460 lex = makeJsonLexContext(json, false);
2461
2462 /* Lex exactly one token from the input and check its type. */
2463 json_lex(lex);
2464 tok = lex_peek(lex);
2465 switch (tok)
2466 {
2467 case JSON_TOKEN_OBJECT_START:
2468 type = "object";
2469 break;
2470 case JSON_TOKEN_ARRAY_START:
2471 type = "array";
2472 break;
2473 case JSON_TOKEN_STRING:
2474 type = "string";
2475 break;
2476 case JSON_TOKEN_NUMBER:
2477 type = "number";
2478 break;
2479 case JSON_TOKEN_TRUE:
2480 case JSON_TOKEN_FALSE:
2481 type = "boolean";
2482 break;
2483 case JSON_TOKEN_NULL:
2484 type = "null";
2485 break;
2486 default:
2487 elog(ERROR, "unexpected json token: %d", tok);
2488 }
2489
2490 PG_RETURN_TEXT_P(cstring_to_text(type));
2491 }
2492