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postgres/src/backend/utils/adt/json.c
Peter Eisentraut 072457b360 Message punctuation and pluralization fixes
2013-08-09 08:02:44 -04:00

1829 lines
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/*-------------------------------------------------------------------------
*
* json.c
* JSON data type support.
*
* Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/backend/utils/adt/json.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/htup_details.h"
#include "access/transam.h"
#include "catalog/pg_cast.h"
#include "catalog/pg_type.h"
#include "executor/spi.h"
#include "lib/stringinfo.h"
#include "libpq/pqformat.h"
#include "mb/pg_wchar.h"
#include "parser/parse_coerce.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/json.h"
#include "utils/jsonapi.h"
#include "utils/typcache.h"
#include "utils/syscache.h"
/*
* The context of the parser is maintained by the recursive descent
* mechanism, but is passed explicitly to the error reporting routine
* for better diagnostics.
*/
typedef enum /* contexts of JSON parser */
{
JSON_PARSE_VALUE, /* expecting a value */
JSON_PARSE_STRING, /* expecting a string (for a field name) */
JSON_PARSE_ARRAY_START, /* saw '[', expecting value or ']' */
JSON_PARSE_ARRAY_NEXT, /* saw array element, expecting ',' or ']' */
JSON_PARSE_OBJECT_START, /* saw '{', expecting label or '}' */
JSON_PARSE_OBJECT_LABEL, /* saw object label, expecting ':' */
JSON_PARSE_OBJECT_NEXT, /* saw object value, expecting ',' or '}' */
JSON_PARSE_OBJECT_COMMA, /* saw object ',', expecting next label */
JSON_PARSE_END /* saw the end of a document, expect nothing */
} JsonParseContext;
static inline void json_lex(JsonLexContext *lex);
static inline void json_lex_string(JsonLexContext *lex);
static inline void json_lex_number(JsonLexContext *lex, char *s);
static inline void parse_scalar(JsonLexContext *lex, JsonSemAction *sem);
static void parse_object_field(JsonLexContext *lex, JsonSemAction *sem);
static void parse_object(JsonLexContext *lex, JsonSemAction *sem);
static void parse_array_element(JsonLexContext *lex, JsonSemAction *sem);
static void parse_array(JsonLexContext *lex, JsonSemAction *sem);
static void report_parse_error(JsonParseContext ctx, JsonLexContext *lex);
static void report_invalid_token(JsonLexContext *lex);
static int report_json_context(JsonLexContext *lex);
static char *extract_mb_char(char *s);
static void composite_to_json(Datum composite, StringInfo result,
bool use_line_feeds);
static void array_dim_to_json(StringInfo result, int dim, int ndims, int *dims,
Datum *vals, bool *nulls, int *valcount,
TYPCATEGORY tcategory, Oid typoutputfunc,
bool use_line_feeds);
static void array_to_json_internal(Datum array, StringInfo result,
bool use_line_feeds);
/* the null action object used for pure validation */
static JsonSemAction nullSemAction =
{
NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL
};
/* Recursive Descent parser support routines */
/*
* lex_peek
*
* what is the current look_ahead token?
*/
static inline JsonTokenType
lex_peek(JsonLexContext *lex)
{
return lex->token_type;
}
/*
* lex_accept
*
* accept the look_ahead token and move the lexer to the next token if the
* look_ahead token matches the token parameter. In that case, and if required,
* also hand back the de-escaped lexeme.
*
* returns true if the token matched, false otherwise.
*/
static inline bool
lex_accept(JsonLexContext *lex, JsonTokenType token, char **lexeme)
{
if (lex->token_type == token)
{
if (lexeme != NULL)
{
if (lex->token_type == JSON_TOKEN_STRING)
{
if (lex->strval != NULL)
*lexeme = pstrdup(lex->strval->data);
}
else
{
int len = (lex->token_terminator - lex->token_start);
char *tokstr = palloc(len + 1);
memcpy(tokstr, lex->token_start, len);
tokstr[len] = '\0';
*lexeme = tokstr;
}
}
json_lex(lex);
return true;
}
return false;
}
/*
* lex_accept
*
* move the lexer to the next token if the current look_ahead token matches
* the parameter token. Otherwise, report an error.
*/
static inline void
lex_expect(JsonParseContext ctx, JsonLexContext *lex, JsonTokenType token)
{
if (!lex_accept(lex, token, NULL))
report_parse_error(ctx, lex);;
}
/*
* All the defined type categories are upper case , so use lower case here
* so we avoid any possible clash.
*/
/* fake type category for JSON so we can distinguish it in datum_to_json */
#define TYPCATEGORY_JSON 'j'
/* fake category for types that have a cast to json */
#define TYPCATEGORY_JSON_CAST 'c'
/* letters appearing in numeric output that aren't valid in a JSON number */
#define NON_NUMERIC_LETTER "NnAaIiFfTtYy"
/* chars to consider as part of an alphanumeric token */
#define JSON_ALPHANUMERIC_CHAR(c) \
(((c) >= 'a' && (c) <= 'z') || \
((c) >= 'A' && (c) <= 'Z') || \
((c) >= '0' && (c) <= '9') || \
(c) == '_' || \
IS_HIGHBIT_SET(c))
/*
* Input.
*/
Datum
json_in(PG_FUNCTION_ARGS)
{
char *json = PG_GETARG_CSTRING(0);
text *result = cstring_to_text(json);
JsonLexContext *lex;
/* validate it */
lex = makeJsonLexContext(result, false);
pg_parse_json(lex, &nullSemAction);
/* Internal representation is the same as text, for now */
PG_RETURN_TEXT_P(result);
}
/*
* Output.
*/
Datum
json_out(PG_FUNCTION_ARGS)
{
/* we needn't detoast because text_to_cstring will handle that */
Datum txt = PG_GETARG_DATUM(0);
PG_RETURN_CSTRING(TextDatumGetCString(txt));
}
/*
* Binary send.
*/
Datum
json_send(PG_FUNCTION_ARGS)
{
text *t = PG_GETARG_TEXT_PP(0);
StringInfoData buf;
pq_begintypsend(&buf);
pq_sendtext(&buf, VARDATA_ANY(t), VARSIZE_ANY_EXHDR(t));
PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
}
/*
* Binary receive.
*/
Datum
json_recv(PG_FUNCTION_ARGS)
{
StringInfo buf = (StringInfo) PG_GETARG_POINTER(0);
text *result;
char *str;
int nbytes;
JsonLexContext *lex;
str = pq_getmsgtext(buf, buf->len - buf->cursor, &nbytes);
result = palloc(nbytes + VARHDRSZ);
SET_VARSIZE(result, nbytes + VARHDRSZ);
memcpy(VARDATA(result), str, nbytes);
/* Validate it. */
lex = makeJsonLexContext(result, false);
pg_parse_json(lex, &nullSemAction);
PG_RETURN_TEXT_P(result);
}
/*
* makeJsonLexContext
*
* lex constructor, with or without StringInfo object
* for de-escaped lexemes.
*
* Without is better as it makes the processing faster, so only make one
* if really required.
*/
JsonLexContext *
makeJsonLexContext(text *json, bool need_escapes)
{
JsonLexContext *lex = palloc0(sizeof(JsonLexContext));
lex->input = lex->token_terminator = lex->line_start = VARDATA(json);
lex->line_number = 1;
lex->input_length = VARSIZE(json) - VARHDRSZ;
if (need_escapes)
lex->strval = makeStringInfo();
return lex;
}
/*
* pg_parse_json
*
* Publicly visible entry point for the JSON parser.
*
* lex is a lexing context, set up for the json to be processed by calling
* makeJsonLexContext(). sem is a strucure of function pointers to semantic
* action routines to be called at appropriate spots during parsing, and a
* pointer to a state object to be passed to those routines.
*/
void
pg_parse_json(JsonLexContext *lex, JsonSemAction *sem)
{
JsonTokenType tok;
/* get the initial token */
json_lex(lex);
tok = lex_peek(lex);
/* parse by recursive descent */
switch (tok)
{
case JSON_TOKEN_OBJECT_START:
parse_object(lex, sem);
break;
case JSON_TOKEN_ARRAY_START:
parse_array(lex, sem);
break;
default:
parse_scalar(lex, sem); /* json can be a bare scalar */
}
lex_expect(JSON_PARSE_END, lex, JSON_TOKEN_END);
}
/*
* Recursive Descent parse routines. There is one for each structural
* element in a json document:
* - scalar (string, number, true, false, null)
* - array ( [ ] )
* - array element
* - object ( { } )
* - object field
*/
static inline void
parse_scalar(JsonLexContext *lex, JsonSemAction *sem)
{
char *val = NULL;
json_scalar_action sfunc = sem->scalar;
char **valaddr;
JsonTokenType tok = lex_peek(lex);
valaddr = sfunc == NULL ? NULL : &val;
/* a scalar must be a string, a number, true, false, or null */
switch (tok)
{
case JSON_TOKEN_TRUE:
lex_accept(lex, JSON_TOKEN_TRUE, valaddr);
break;
case JSON_TOKEN_FALSE:
lex_accept(lex, JSON_TOKEN_FALSE, valaddr);
break;
case JSON_TOKEN_NULL:
lex_accept(lex, JSON_TOKEN_NULL, valaddr);
break;
case JSON_TOKEN_NUMBER:
lex_accept(lex, JSON_TOKEN_NUMBER, valaddr);
break;
case JSON_TOKEN_STRING:
lex_accept(lex, JSON_TOKEN_STRING, valaddr);
break;
default:
report_parse_error(JSON_PARSE_VALUE, lex);
}
if (sfunc != NULL)
(*sfunc) (sem->semstate, val, tok);
}
static void
parse_object_field(JsonLexContext *lex, JsonSemAction *sem)
{
/*
* an object field is "fieldname" : value where value can be a scalar,
* object or array
*/
char *fname = NULL; /* keep compiler quiet */
json_ofield_action ostart = sem->object_field_start;
json_ofield_action oend = sem->object_field_end;
bool isnull;
char **fnameaddr = NULL;
JsonTokenType tok;
if (ostart != NULL || oend != NULL)
fnameaddr = &fname;
if (!lex_accept(lex, JSON_TOKEN_STRING, fnameaddr))
report_parse_error(JSON_PARSE_STRING, lex);
lex_expect(JSON_PARSE_OBJECT_LABEL, lex, JSON_TOKEN_COLON);
tok = lex_peek(lex);
isnull = tok == JSON_TOKEN_NULL;
if (ostart != NULL)
(*ostart) (sem->semstate, fname, isnull);
switch (tok)
{
case JSON_TOKEN_OBJECT_START:
parse_object(lex, sem);
break;
case JSON_TOKEN_ARRAY_START:
parse_array(lex, sem);
break;
default:
parse_scalar(lex, sem);
}
if (oend != NULL)
(*oend) (sem->semstate, fname, isnull);
if (fname != NULL)
pfree(fname);
}
static void
parse_object(JsonLexContext *lex, JsonSemAction *sem)
{
/*
* an object is a possibly empty sequence of object fields, separated by
* commas and surrounde by curly braces.
*/
json_struct_action ostart = sem->object_start;
json_struct_action oend = sem->object_end;
JsonTokenType tok;
if (ostart != NULL)
(*ostart) (sem->semstate);
/*
* Data inside an object at at a higher nesting level than the object
* itself. Note that we increment this after we call the semantic routine
* for the object start and restore it before we call the routine for the
* object end.
*/
lex->lex_level++;
/* we know this will succeeed, just clearing the token */
lex_expect(JSON_PARSE_OBJECT_START, lex, JSON_TOKEN_OBJECT_START);
tok = lex_peek(lex);
switch (tok)
{
case JSON_TOKEN_STRING:
parse_object_field(lex, sem);
while (lex_accept(lex, JSON_TOKEN_COMMA, NULL))
parse_object_field(lex, sem);
break;
case JSON_TOKEN_OBJECT_END:
break;
default:
/* case of an invalid initial token inside the object */
report_parse_error(JSON_PARSE_OBJECT_START, lex);
}
lex_expect(JSON_PARSE_OBJECT_NEXT, lex, JSON_TOKEN_OBJECT_END);
lex->lex_level--;
if (oend != NULL)
(*oend) (sem->semstate);
}
static void
parse_array_element(JsonLexContext *lex, JsonSemAction *sem)
{
json_aelem_action astart = sem->array_element_start;
json_aelem_action aend = sem->array_element_end;
JsonTokenType tok = lex_peek(lex);
bool isnull;
isnull = tok == JSON_TOKEN_NULL;
if (astart != NULL)
(*astart) (sem->semstate, isnull);
/* an array element is any object, array or scalar */
switch (tok)
{
case JSON_TOKEN_OBJECT_START:
parse_object(lex, sem);
break;
case JSON_TOKEN_ARRAY_START:
parse_array(lex, sem);
break;
default:
parse_scalar(lex, sem);
}
if (aend != NULL)
(*aend) (sem->semstate, isnull);
}
static void
parse_array(JsonLexContext *lex, JsonSemAction *sem)
{
/*
* an array is a possibly empty sequence of array elements, separated by
* commas and surrounded by square brackets.
*/
json_struct_action astart = sem->array_start;
json_struct_action aend = sem->array_end;
if (astart != NULL)
(*astart) (sem->semstate);
/*
* Data inside an array at at a higher nesting level than the array
* itself. Note that we increment this after we call the semantic routine
* for the array start and restore it before we call the routine for the
* array end.
*/
lex->lex_level++;
lex_expect(JSON_PARSE_ARRAY_START, lex, JSON_TOKEN_ARRAY_START);
if (lex_peek(lex) != JSON_TOKEN_ARRAY_END)
{
parse_array_element(lex, sem);
while (lex_accept(lex, JSON_TOKEN_COMMA, NULL))
parse_array_element(lex, sem);
}
lex_expect(JSON_PARSE_ARRAY_NEXT, lex, JSON_TOKEN_ARRAY_END);
lex->lex_level--;
if (aend != NULL)
(*aend) (sem->semstate);
}
/*
* Lex one token from the input stream.
*/
static inline void
json_lex(JsonLexContext *lex)
{
char *s;
int len;
/* Skip leading whitespace. */
s = lex->token_terminator;
len = s - lex->input;
while (len < lex->input_length &&
(*s == ' ' || *s == '\t' || *s == '\n' || *s == '\r'))
{
if (*s == '\n')
++lex->line_number;
++s;
++len;
}
lex->token_start = s;
/* Determine token type. */
if (len >= lex->input_length)
{
lex->token_start = NULL;
lex->prev_token_terminator = lex->token_terminator;
lex->token_terminator = s;
lex->token_type = JSON_TOKEN_END;
}
else
switch (*s)
{
/* Single-character token, some kind of punctuation mark. */
case '{':
lex->prev_token_terminator = lex->token_terminator;
lex->token_terminator = s + 1;
lex->token_type = JSON_TOKEN_OBJECT_START;
break;
case '}':
lex->prev_token_terminator = lex->token_terminator;
lex->token_terminator = s + 1;
lex->token_type = JSON_TOKEN_OBJECT_END;
break;
case '[':
lex->prev_token_terminator = lex->token_terminator;
lex->token_terminator = s + 1;
lex->token_type = JSON_TOKEN_ARRAY_START;
break;
case ']':
lex->prev_token_terminator = lex->token_terminator;
lex->token_terminator = s + 1;
lex->token_type = JSON_TOKEN_ARRAY_END;
break;
case ',':
lex->prev_token_terminator = lex->token_terminator;
lex->token_terminator = s + 1;
lex->token_type = JSON_TOKEN_COMMA;
break;
case ':':
lex->prev_token_terminator = lex->token_terminator;
lex->token_terminator = s + 1;
lex->token_type = JSON_TOKEN_COLON;
break;
case '"':
/* string */
json_lex_string(lex);
lex->token_type = JSON_TOKEN_STRING;
break;
case '-':
/* Negative number. */
json_lex_number(lex, s + 1);
lex->token_type = JSON_TOKEN_NUMBER;
break;
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
/* Positive number. */
json_lex_number(lex, s);
lex->token_type = JSON_TOKEN_NUMBER;
break;
default:
{
char *p;
/*
* We're not dealing with a string, number, legal
* punctuation mark, or end of string. The only legal
* tokens we might find here are true, false, and null,
* but for error reporting purposes we scan until we see a
* non-alphanumeric character. That way, we can report
* the whole word as an unexpected token, rather than just
* some unintuitive prefix thereof.
*/
for (p = s; p - s < lex->input_length - len && JSON_ALPHANUMERIC_CHAR(*p); p++)
/* skip */ ;
/*
* We got some sort of unexpected punctuation or an
* otherwise unexpected character, so just complain about
* that one character.
*/
if (p == s)
{
lex->prev_token_terminator = lex->token_terminator;
lex->token_terminator = s + 1;
report_invalid_token(lex);
}
/*
* We've got a real alphanumeric token here. If it
* happens to be true, false, or null, all is well. If
* not, error out.
*/
lex->prev_token_terminator = lex->token_terminator;
lex->token_terminator = p;
if (p - s == 4)
{
if (memcmp(s, "true", 4) == 0)
lex->token_type = JSON_TOKEN_TRUE;
else if (memcmp(s, "null", 4) == 0)
lex->token_type = JSON_TOKEN_NULL;
else
report_invalid_token(lex);
}
else if (p - s == 5 && memcmp(s, "false", 5) == 0)
lex->token_type = JSON_TOKEN_FALSE;
else
report_invalid_token(lex);
}
} /* end of switch */
}
/*
* The next token in the input stream is known to be a string; lex it.
*/
static inline void
json_lex_string(JsonLexContext *lex)
{
char *s;
int len;
int hi_surrogate = -1;
if (lex->strval != NULL)
resetStringInfo(lex->strval);
Assert(lex->input_length > 0);
s = lex->token_start;
len = lex->token_start - lex->input;
for (;;)
{
s++;
len++;
/* Premature end of the string. */
if (len >= lex->input_length)
{
lex->token_terminator = s;
report_invalid_token(lex);
}
else if (*s == '"')
break;
else if ((unsigned char) *s < 32)
{
/* Per RFC4627, these characters MUST be escaped. */
/* Since *s isn't printable, exclude it from the context string */
lex->token_terminator = s;
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("Character with value 0x%02x must be escaped.",
(unsigned char) *s),
report_json_context(lex)));
}
else if (*s == '\\')
{
/* OK, we have an escape character. */
s++;
len++;
if (len >= lex->input_length)
{
lex->token_terminator = s;
report_invalid_token(lex);
}
else if (*s == 'u')
{
int i;
int ch = 0;
for (i = 1; i <= 4; i++)
{
s++;
len++;
if (len >= lex->input_length)
{
lex->token_terminator = s;
report_invalid_token(lex);
}
else if (*s >= '0' && *s <= '9')
ch = (ch * 16) + (*s - '0');
else if (*s >= 'a' && *s <= 'f')
ch = (ch * 16) + (*s - 'a') + 10;
else if (*s >= 'A' && *s <= 'F')
ch = (ch * 16) + (*s - 'A') + 10;
else
{
lex->token_terminator = s + pg_mblen(s);
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("\"\\u\" must be followed by four hexadecimal digits."),
report_json_context(lex)));
}
}
if (lex->strval != NULL)
{
char utf8str[5];
int utf8len;
if (ch >= 0xd800 && ch <= 0xdbff)
{
if (hi_surrogate != -1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("Unicode high surrogate must not follow a high surrogate."),
report_json_context(lex)));
hi_surrogate = (ch & 0x3ff) << 10;
continue;
}
else if (ch >= 0xdc00 && ch <= 0xdfff)
{
if (hi_surrogate == -1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("Unicode low surrogate must follow a high surrogate."),
report_json_context(lex)));
ch = 0x10000 + hi_surrogate + (ch & 0x3ff);
hi_surrogate = -1;
}
if (hi_surrogate != -1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("Unicode low surrogate must follow a high surrogate."),
report_json_context(lex)));
/*
* For UTF8, replace the escape sequence by the actual utf8
* character in lex->strval. Do this also for other encodings
* if the escape designates an ASCII character, otherwise
* raise an error. We don't ever unescape a \u0000, since that
* would result in an impermissible nul byte.
*/
if (ch == 0)
{
appendStringInfoString(lex->strval, "\\u0000");
}
else if (GetDatabaseEncoding() == PG_UTF8)
{
unicode_to_utf8(ch, (unsigned char *) utf8str);
utf8len = pg_utf_mblen((unsigned char *) utf8str);
appendBinaryStringInfo(lex->strval, utf8str, utf8len);
}
else if (ch <= 0x007f)
{
/*
* This is the only way to designate things like a form feed
* character in JSON, so it's useful in all encodings.
*/
appendStringInfoChar(lex->strval, (char) ch);
}
else
{
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("Unicode escape values cannot be used for code point values above 007F when the server encoding is not UTF8."),
report_json_context(lex)));
}
}
}
else if (lex->strval != NULL)
{
if (hi_surrogate != -1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("Unicode low surrogate must follow a high surrogate."),
report_json_context(lex)));
switch (*s)
{
case '"':
case '\\':
case '/':
appendStringInfoChar(lex->strval, *s);
break;
case 'b':
appendStringInfoChar(lex->strval, '\b');
break;
case 'f':
appendStringInfoChar(lex->strval, '\f');
break;
case 'n':
appendStringInfoChar(lex->strval, '\n');
break;
case 'r':
appendStringInfoChar(lex->strval, '\r');
break;
case 't':
appendStringInfoChar(lex->strval, '\t');
break;
default:
/* Not a valid string escape, so error out. */
lex->token_terminator = s + pg_mblen(s);
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("Escape sequence \"\\%s\" is invalid.",
extract_mb_char(s)),
report_json_context(lex)));
}
}
else if (strchr("\"\\/bfnrt", *s) == NULL)
{
/*
* Simpler processing if we're not bothered about de-escaping
*
* It's very tempting to remove the strchr() call here and
* replace it with a switch statement, but testing so far has
* shown it's not a performance win.
*/
lex->token_terminator = s + pg_mblen(s);
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("Escape sequence \"\\%s\" is invalid.",
extract_mb_char(s)),
report_json_context(lex)));
}
}
else if (lex->strval != NULL)
{
if (hi_surrogate != -1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("Unicode low surrogate must follow a high surrogate."),
report_json_context(lex)));
appendStringInfoChar(lex->strval, *s);
}
}
if (hi_surrogate != -1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("Unicode low surrogate must follow a high surrogate."),
report_json_context(lex)));
/* Hooray, we found the end of the string! */
lex->prev_token_terminator = lex->token_terminator;
lex->token_terminator = s + 1;
}
/*-------------------------------------------------------------------------
* The next token in the input stream is known to be a number; lex it.
*
* In JSON, a number consists of four parts:
*
* (1) An optional minus sign ('-').
*
* (2) Either a single '0', or a string of one or more digits that does not
* begin with a '0'.
*
* (3) An optional decimal part, consisting of a period ('.') followed by
* one or more digits. (Note: While this part can be omitted
* completely, it's not OK to have only the decimal point without
* any digits afterwards.)
*
* (4) An optional exponent part, consisting of 'e' or 'E', optionally
* followed by '+' or '-', followed by one or more digits. (Note:
* As with the decimal part, if 'e' or 'E' is present, it must be
* followed by at least one digit.)
*
* The 's' argument to this function points to the ostensible beginning
* of part 2 - i.e. the character after any optional minus sign, and the
* first character of the string if there is none.
*
*-------------------------------------------------------------------------
*/
static inline void
json_lex_number(JsonLexContext *lex, char *s)
{
bool error = false;
char *p;
int len;
len = s - lex->input;
/* Part (1): leading sign indicator. */
/* Caller already did this for us; so do nothing. */
/* Part (2): parse main digit string. */
if (*s == '0')
{
s++;
len++;
}
else if (*s >= '1' && *s <= '9')
{
do
{
s++;
len++;
} while (len < lex->input_length && *s >= '0' && *s <= '9');
}
else
error = true;
/* Part (3): parse optional decimal portion. */
if (len < lex->input_length && *s == '.')
{
s++;
len++;
if (len == lex->input_length || *s < '0' || *s > '9')
error = true;
else
{
do
{
s++;
len++;
} while (len < lex->input_length && *s >= '0' && *s <= '9');
}
}
/* Part (4): parse optional exponent. */
if (len < lex->input_length && (*s == 'e' || *s == 'E'))
{
s++;
len++;
if (len < lex->input_length && (*s == '+' || *s == '-'))
{
s++;
len++;
}
if (len == lex->input_length || *s < '0' || *s > '9')
error = true;
else
{
do
{
s++;
len++;
} while (len < lex->input_length && *s >= '0' && *s <= '9');
}
}
/*
* Check for trailing garbage. As in json_lex(), any alphanumeric stuff
* here should be considered part of the token for error-reporting
* purposes.
*/
for (p = s; len < lex->input_length && JSON_ALPHANUMERIC_CHAR(*p); p++, len++)
error = true;
lex->prev_token_terminator = lex->token_terminator;
lex->token_terminator = p;
if (error)
report_invalid_token(lex);
}
/*
* Report a parse error.
*
* lex->token_start and lex->token_terminator must identify the current token.
*/
static void
report_parse_error(JsonParseContext ctx, JsonLexContext *lex)
{
char *token;
int toklen;
/* Handle case where the input ended prematurely. */
if (lex->token_start == NULL || lex->token_type == JSON_TOKEN_END)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("The input string ended unexpectedly."),
report_json_context(lex)));
/* Separate out the current token. */
toklen = lex->token_terminator - lex->token_start;
token = palloc(toklen + 1);
memcpy(token, lex->token_start, toklen);
token[toklen] = '\0';
/* Complain, with the appropriate detail message. */
if (ctx == JSON_PARSE_END)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("Expected end of input, but found \"%s\".",
token),
report_json_context(lex)));
else
{
switch (ctx)
{
case JSON_PARSE_VALUE:
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("Expected JSON value, but found \"%s\".",
token),
report_json_context(lex)));
break;
case JSON_PARSE_STRING:
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("Expected string, but found \"%s\".",
token),
report_json_context(lex)));
break;
case JSON_PARSE_ARRAY_START:
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("Expected array element or \"]\", but found \"%s\".",
token),
report_json_context(lex)));
break;
case JSON_PARSE_ARRAY_NEXT:
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("Expected \",\" or \"]\", but found \"%s\".",
token),
report_json_context(lex)));
break;
case JSON_PARSE_OBJECT_START:
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("Expected string or \"}\", but found \"%s\".",
token),
report_json_context(lex)));
break;
case JSON_PARSE_OBJECT_LABEL:
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("Expected \":\", but found \"%s\".",
token),
report_json_context(lex)));
break;
case JSON_PARSE_OBJECT_NEXT:
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("Expected \",\" or \"}\", but found \"%s\".",
token),
report_json_context(lex)));
break;
case JSON_PARSE_OBJECT_COMMA:
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("Expected string, but found \"%s\".",
token),
report_json_context(lex)));
break;
default:
elog(ERROR, "unexpected json parse state: %d", ctx);
}
}
}
/*
* Report an invalid input token.
*
* lex->token_start and lex->token_terminator must identify the token.
*/
static void
report_invalid_token(JsonLexContext *lex)
{
char *token;
int toklen;
/* Separate out the offending token. */
toklen = lex->token_terminator - lex->token_start;
token = palloc(toklen + 1);
memcpy(token, lex->token_start, toklen);
token[toklen] = '\0';
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type json"),
errdetail("Token \"%s\" is invalid.", token),
report_json_context(lex)));
}
/*
* Report a CONTEXT line for bogus JSON input.
*
* lex->token_terminator must be set to identify the spot where we detected
* the error. Note that lex->token_start might be NULL, in case we recognized
* error at EOF.
*
* The return value isn't meaningful, but we make it non-void so that this
* can be invoked inside ereport().
*/
static int
report_json_context(JsonLexContext *lex)
{
const char *context_start;
const char *context_end;
const char *line_start;
int line_number;
char *ctxt;
int ctxtlen;
const char *prefix;
const char *suffix;
/* Choose boundaries for the part of the input we will display */
context_start = lex->input;
context_end = lex->token_terminator;
line_start = context_start;
line_number = 1;
for (;;)
{
/* Always advance over newlines */
if (context_start < context_end && *context_start == '\n')
{
context_start++;
line_start = context_start;
line_number++;
continue;
}
/* Otherwise, done as soon as we are close enough to context_end */
if (context_end - context_start < 50)
break;
/* Advance to next multibyte character */
if (IS_HIGHBIT_SET(*context_start))
context_start += pg_mblen(context_start);
else
context_start++;
}
/*
* We add "..." to indicate that the excerpt doesn't start at the
* beginning of the line ... but if we're within 3 characters of the
* beginning of the line, we might as well just show the whole line.
*/
if (context_start - line_start <= 3)
context_start = line_start;
/* Get a null-terminated copy of the data to present */
ctxtlen = context_end - context_start;
ctxt = palloc(ctxtlen + 1);
memcpy(ctxt, context_start, ctxtlen);
ctxt[ctxtlen] = '\0';
/*
* Show the context, prefixing "..." if not starting at start of line, and
* suffixing "..." if not ending at end of line.
*/
prefix = (context_start > line_start) ? "..." : "";
suffix = (lex->token_type != JSON_TOKEN_END && context_end - lex->input < lex->input_length && *context_end != '\n' && *context_end != '\r') ? "..." : "";
return errcontext("JSON data, line %d: %s%s%s",
line_number, prefix, ctxt, suffix);
}
/*
* Extract a single, possibly multi-byte char from the input string.
*/
static char *
extract_mb_char(char *s)
{
char *res;
int len;
len = pg_mblen(s);
res = palloc(len + 1);
memcpy(res, s, len);
res[len] = '\0';
return res;
}
/*
* Turn a scalar Datum into JSON, appending the string to "result".
*
* Hand off a non-scalar datum to composite_to_json or array_to_json_internal
* as appropriate.
*/
static void
datum_to_json(Datum val, bool is_null, StringInfo result,
TYPCATEGORY tcategory, Oid typoutputfunc)
{
char *outputstr;
text *jsontext;
if (is_null)
{
appendStringInfoString(result, "null");
return;
}
switch (tcategory)
{
case TYPCATEGORY_ARRAY:
array_to_json_internal(val, result, false);
break;
case TYPCATEGORY_COMPOSITE:
composite_to_json(val, result, false);
break;
case TYPCATEGORY_BOOLEAN:
if (DatumGetBool(val))
appendStringInfoString(result, "true");
else
appendStringInfoString(result, "false");
break;
case TYPCATEGORY_NUMERIC:
outputstr = OidOutputFunctionCall(typoutputfunc, val);
/*
* Don't call escape_json here if it's a valid JSON number.
* Numeric output should usually be a valid JSON number and JSON
* numbers shouldn't be quoted. Quote cases like "Nan" and
* "Infinity", however.
*/
if (strpbrk(outputstr, NON_NUMERIC_LETTER) == NULL)
appendStringInfoString(result, outputstr);
else
escape_json(result, outputstr);
pfree(outputstr);
break;
case TYPCATEGORY_JSON:
/* JSON will already be escaped */
outputstr = OidOutputFunctionCall(typoutputfunc, val);
appendStringInfoString(result, outputstr);
pfree(outputstr);
break;
case TYPCATEGORY_JSON_CAST:
jsontext = DatumGetTextP(OidFunctionCall1(typoutputfunc, val));
outputstr = text_to_cstring(jsontext);
appendStringInfoString(result, outputstr);
pfree(outputstr);
pfree(jsontext);
break;
default:
outputstr = OidOutputFunctionCall(typoutputfunc, val);
escape_json(result, outputstr);
pfree(outputstr);
break;
}
}
/*
* Process a single dimension of an array.
* If it's the innermost dimension, output the values, otherwise call
* ourselves recursively to process the next dimension.
*/
static void
array_dim_to_json(StringInfo result, int dim, int ndims, int *dims, Datum *vals,
bool *nulls, int *valcount, TYPCATEGORY tcategory,
Oid typoutputfunc, bool use_line_feeds)
{
int i;
const char *sep;
Assert(dim < ndims);
sep = use_line_feeds ? ",\n " : ",";
appendStringInfoChar(result, '[');
for (i = 1; i <= dims[dim]; i++)
{
if (i > 1)
appendStringInfoString(result, sep);
if (dim + 1 == ndims)
{
datum_to_json(vals[*valcount], nulls[*valcount], result, tcategory,
typoutputfunc);
(*valcount)++;
}
else
{
/*
* Do we want line feeds on inner dimensions of arrays? For now
* we'll say no.
*/
array_dim_to_json(result, dim + 1, ndims, dims, vals, nulls,
valcount, tcategory, typoutputfunc, false);
}
}
appendStringInfoChar(result, ']');
}
/*
* Turn an array into JSON.
*/
static void
array_to_json_internal(Datum array, StringInfo result, bool use_line_feeds)
{
ArrayType *v = DatumGetArrayTypeP(array);
Oid element_type = ARR_ELEMTYPE(v);
int *dim;
int ndim;
int nitems;
int count = 0;
Datum *elements;
bool *nulls;
int16 typlen;
bool typbyval;
char typalign,
typdelim;
Oid typioparam;
Oid typoutputfunc;
TYPCATEGORY tcategory;
Oid castfunc = InvalidOid;
ndim = ARR_NDIM(v);
dim = ARR_DIMS(v);
nitems = ArrayGetNItems(ndim, dim);
if (nitems <= 0)
{
appendStringInfoString(result, "[]");
return;
}
get_type_io_data(element_type, IOFunc_output,
&typlen, &typbyval, &typalign,
&typdelim, &typioparam, &typoutputfunc);
if (element_type > FirstNormalObjectId)
{
HeapTuple tuple;
Form_pg_cast castForm;
tuple = SearchSysCache2(CASTSOURCETARGET,
ObjectIdGetDatum(element_type),
ObjectIdGetDatum(JSONOID));
if (HeapTupleIsValid(tuple))
{
castForm = (Form_pg_cast) GETSTRUCT(tuple);
if (castForm->castmethod == COERCION_METHOD_FUNCTION)
castfunc = typoutputfunc = castForm->castfunc;
ReleaseSysCache(tuple);
}
}
deconstruct_array(v, element_type, typlen, typbyval,
typalign, &elements, &nulls,
&nitems);
if (castfunc != InvalidOid)
tcategory = TYPCATEGORY_JSON_CAST;
else if (element_type == RECORDOID)
tcategory = TYPCATEGORY_COMPOSITE;
else if (element_type == JSONOID)
tcategory = TYPCATEGORY_JSON;
else
tcategory = TypeCategory(element_type);
array_dim_to_json(result, 0, ndim, dim, elements, nulls, &count, tcategory,
typoutputfunc, use_line_feeds);
pfree(elements);
pfree(nulls);
}
/*
* Turn a composite / record into JSON.
*/
static void
composite_to_json(Datum composite, StringInfo result, bool use_line_feeds)
{
HeapTupleHeader td;
Oid tupType;
int32 tupTypmod;
TupleDesc tupdesc;
HeapTupleData tmptup,
*tuple;
int i;
bool needsep = false;
const char *sep;
sep = use_line_feeds ? ",\n " : ",";
td = DatumGetHeapTupleHeader(composite);
/* Extract rowtype info and find a tupdesc */
tupType = HeapTupleHeaderGetTypeId(td);
tupTypmod = HeapTupleHeaderGetTypMod(td);
tupdesc = lookup_rowtype_tupdesc(tupType, tupTypmod);
/* Build a temporary HeapTuple control structure */
tmptup.t_len = HeapTupleHeaderGetDatumLength(td);
tmptup.t_data = td;
tuple = &tmptup;
appendStringInfoChar(result, '{');
for (i = 0; i < tupdesc->natts; i++)
{
Datum val,
origval;
bool isnull;
char *attname;
TYPCATEGORY tcategory;
Oid typoutput;
bool typisvarlena;
Oid castfunc = InvalidOid;
if (tupdesc->attrs[i]->attisdropped)
continue;
if (needsep)
appendStringInfoString(result, sep);
needsep = true;
attname = NameStr(tupdesc->attrs[i]->attname);
escape_json(result, attname);
appendStringInfoChar(result, ':');
origval = heap_getattr(tuple, i + 1, tupdesc, &isnull);
getTypeOutputInfo(tupdesc->attrs[i]->atttypid,
&typoutput, &typisvarlena);
if (tupdesc->attrs[i]->atttypid > FirstNormalObjectId)
{
HeapTuple cast_tuple;
Form_pg_cast castForm;
cast_tuple = SearchSysCache2(CASTSOURCETARGET,
ObjectIdGetDatum(tupdesc->attrs[i]->atttypid),
ObjectIdGetDatum(JSONOID));
if (HeapTupleIsValid(cast_tuple))
{
castForm = (Form_pg_cast) GETSTRUCT(cast_tuple);
if (castForm->castmethod == COERCION_METHOD_FUNCTION)
castfunc = typoutput = castForm->castfunc;
ReleaseSysCache(cast_tuple);
}
}
if (castfunc != InvalidOid)
tcategory = TYPCATEGORY_JSON_CAST;
else if (tupdesc->attrs[i]->atttypid == RECORDARRAYOID)
tcategory = TYPCATEGORY_ARRAY;
else if (tupdesc->attrs[i]->atttypid == RECORDOID)
tcategory = TYPCATEGORY_COMPOSITE;
else if (tupdesc->attrs[i]->atttypid == JSONOID)
tcategory = TYPCATEGORY_JSON;
else
tcategory = TypeCategory(tupdesc->attrs[i]->atttypid);
/*
* If we have a toasted datum, forcibly detoast it here to avoid
* memory leakage inside the type's output routine.
*/
if (typisvarlena && !isnull)
val = PointerGetDatum(PG_DETOAST_DATUM(origval));
else
val = origval;
datum_to_json(val, isnull, result, tcategory, typoutput);
/* Clean up detoasted copy, if any */
if (val != origval)
pfree(DatumGetPointer(val));
}
appendStringInfoChar(result, '}');
ReleaseTupleDesc(tupdesc);
}
/*
* SQL function array_to_json(row)
*/
extern Datum
array_to_json(PG_FUNCTION_ARGS)
{
Datum array = PG_GETARG_DATUM(0);
StringInfo result;
result = makeStringInfo();
array_to_json_internal(array, result, false);
PG_RETURN_TEXT_P(cstring_to_text(result->data));
}
/*
* SQL function array_to_json(row, prettybool)
*/
extern Datum
array_to_json_pretty(PG_FUNCTION_ARGS)
{
Datum array = PG_GETARG_DATUM(0);
bool use_line_feeds = PG_GETARG_BOOL(1);
StringInfo result;
result = makeStringInfo();
array_to_json_internal(array, result, use_line_feeds);
PG_RETURN_TEXT_P(cstring_to_text(result->data));
}
/*
* SQL function row_to_json(row)
*/
extern Datum
row_to_json(PG_FUNCTION_ARGS)
{
Datum array = PG_GETARG_DATUM(0);
StringInfo result;
result = makeStringInfo();
composite_to_json(array, result, false);
PG_RETURN_TEXT_P(cstring_to_text(result->data));
}
/*
* SQL function row_to_json(row, prettybool)
*/
extern Datum
row_to_json_pretty(PG_FUNCTION_ARGS)
{
Datum array = PG_GETARG_DATUM(0);
bool use_line_feeds = PG_GETARG_BOOL(1);
StringInfo result;
result = makeStringInfo();
composite_to_json(array, result, use_line_feeds);
PG_RETURN_TEXT_P(cstring_to_text(result->data));
}
/*
* SQL function to_json(anyvalue)
*/
Datum
to_json(PG_FUNCTION_ARGS)
{
Oid val_type = get_fn_expr_argtype(fcinfo->flinfo, 0);
StringInfo result;
Datum orig_val,
val;
TYPCATEGORY tcategory;
Oid typoutput;
bool typisvarlena;
Oid castfunc = InvalidOid;
if (val_type == InvalidOid)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("could not determine input data type")));
result = makeStringInfo();
orig_val = PG_ARGISNULL(0) ? (Datum) 0 : PG_GETARG_DATUM(0);
getTypeOutputInfo(val_type, &typoutput, &typisvarlena);
if (val_type > FirstNormalObjectId)
{
HeapTuple tuple;
Form_pg_cast castForm;
tuple = SearchSysCache2(CASTSOURCETARGET,
ObjectIdGetDatum(val_type),
ObjectIdGetDatum(JSONOID));
if (HeapTupleIsValid(tuple))
{
castForm = (Form_pg_cast) GETSTRUCT(tuple);
if (castForm->castmethod == COERCION_METHOD_FUNCTION)
castfunc = typoutput = castForm->castfunc;
ReleaseSysCache(tuple);
}
}
if (castfunc != InvalidOid)
tcategory = TYPCATEGORY_JSON_CAST;
else if (val_type == RECORDARRAYOID)
tcategory = TYPCATEGORY_ARRAY;
else if (val_type == RECORDOID)
tcategory = TYPCATEGORY_COMPOSITE;
else if (val_type == JSONOID)
tcategory = TYPCATEGORY_JSON;
else
tcategory = TypeCategory(val_type);
/*
* If we have a toasted datum, forcibly detoast it here to avoid memory
* leakage inside the type's output routine.
*/
if (typisvarlena && orig_val != (Datum) 0)
val = PointerGetDatum(PG_DETOAST_DATUM(orig_val));
else
val = orig_val;
datum_to_json(val, false, result, tcategory, typoutput);
/* Clean up detoasted copy, if any */
if (val != orig_val)
pfree(DatumGetPointer(val));
PG_RETURN_TEXT_P(cstring_to_text(result->data));
}
/*
* json_agg transition function
*/
Datum
json_agg_transfn(PG_FUNCTION_ARGS)
{
Oid val_type = get_fn_expr_argtype(fcinfo->flinfo, 1);
MemoryContext aggcontext,
oldcontext;
StringInfo state;
Datum orig_val,
val;
TYPCATEGORY tcategory;
Oid typoutput;
bool typisvarlena;
Oid castfunc = InvalidOid;
if (val_type == InvalidOid)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("could not determine input data type")));
if (!AggCheckCallContext(fcinfo, &aggcontext))
{
/* cannot be called directly because of internal-type argument */
elog(ERROR, "json_agg_transfn called in non-aggregate context");
}
if (PG_ARGISNULL(0))
{
/*
* Make this StringInfo in a context where it will persist for the
* duration off the aggregate call. It's only needed for this initial
* piece, as the StringInfo routines make sure they use the right
* context to enlarge the object if necessary.
*/
oldcontext = MemoryContextSwitchTo(aggcontext);
state = makeStringInfo();
MemoryContextSwitchTo(oldcontext);
appendStringInfoChar(state, '[');
}
else
{
state = (StringInfo) PG_GETARG_POINTER(0);
appendStringInfoString(state, ", ");
}
/* fast path for NULLs */
if (PG_ARGISNULL(1))
{
orig_val = (Datum) 0;
datum_to_json(orig_val, true, state, 0, InvalidOid);
PG_RETURN_POINTER(state);
}
orig_val = PG_GETARG_DATUM(1);
getTypeOutputInfo(val_type, &typoutput, &typisvarlena);
if (val_type > FirstNormalObjectId)
{
HeapTuple tuple;
Form_pg_cast castForm;
tuple = SearchSysCache2(CASTSOURCETARGET,
ObjectIdGetDatum(val_type),
ObjectIdGetDatum(JSONOID));
if (HeapTupleIsValid(tuple))
{
castForm = (Form_pg_cast) GETSTRUCT(tuple);
if (castForm->castmethod == COERCION_METHOD_FUNCTION)
castfunc = typoutput = castForm->castfunc;
ReleaseSysCache(tuple);
}
}
if (castfunc != InvalidOid)
tcategory = TYPCATEGORY_JSON_CAST;
else if (val_type == RECORDARRAYOID)
tcategory = TYPCATEGORY_ARRAY;
else if (val_type == RECORDOID)
tcategory = TYPCATEGORY_COMPOSITE;
else if (val_type == JSONOID)
tcategory = TYPCATEGORY_JSON;
else
tcategory = TypeCategory(val_type);
/*
* If we have a toasted datum, forcibly detoast it here to avoid memory
* leakage inside the type's output routine.
*/
if (typisvarlena)
val = PointerGetDatum(PG_DETOAST_DATUM(orig_val));
else
val = orig_val;
if (!PG_ARGISNULL(0) &&
(tcategory == TYPCATEGORY_ARRAY || tcategory == TYPCATEGORY_COMPOSITE))
{
appendStringInfoString(state, "\n ");
}
datum_to_json(val, false, state, tcategory, typoutput);
/* Clean up detoasted copy, if any */
if (val != orig_val)
pfree(DatumGetPointer(val));
/*
* The transition type for array_agg() is declared to be "internal", which
* is a pass-by-value type the same size as a pointer. So we can safely
* pass the ArrayBuildState pointer through nodeAgg.c's machinations.
*/
PG_RETURN_POINTER(state);
}
/*
* json_agg final function
*/
Datum
json_agg_finalfn(PG_FUNCTION_ARGS)
{
StringInfo state;
/* cannot be called directly because of internal-type argument */
Assert(AggCheckCallContext(fcinfo, NULL));
state = PG_ARGISNULL(0) ? NULL : (StringInfo) PG_GETARG_POINTER(0);
if (state == NULL)
PG_RETURN_NULL();
appendStringInfoChar(state, ']');
PG_RETURN_TEXT_P(cstring_to_text(state->data));
}
/*
* Produce a JSON string literal, properly escaping characters in the text.
*/
void
escape_json(StringInfo buf, const char *str)
{
const char *p;
appendStringInfoCharMacro(buf, '\"');
for (p = str; *p; p++)
{
switch (*p)
{
case '\b':
appendStringInfoString(buf, "\\b");
break;
case '\f':
appendStringInfoString(buf, "\\f");
break;
case '\n':
appendStringInfoString(buf, "\\n");
break;
case '\r':
appendStringInfoString(buf, "\\r");
break;
case '\t':
appendStringInfoString(buf, "\\t");
break;
case '"':
appendStringInfoString(buf, "\\\"");
break;
case '\\':
appendStringInfoString(buf, "\\\\");
break;
default:
if ((unsigned char) *p < ' ')
appendStringInfo(buf, "\\u%04x", (int) *p);
else
appendStringInfoCharMacro(buf, *p);
break;
}
}
appendStringInfoCharMacro(buf, '\"');
}
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