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postgres/src/backend/utils/adt/json.c
Stephen Frost 95d737ff45 Add 'ignore_nulls' option to row_to_json 
Provide an option to skip NULL values in a row when generating a JSON
object from that row with row_to_json.  This can reduce the size of the
JSON object in cases where columns are NULL without really reducing the
information in the JSON object.

This also makes row_to_json into a single function with default values,
rather than having multiple functions.  In passing, change array_to_json
to also be a single function with default values (we don't add an
'ignore_nulls' option yet- it's not clear that there is a sensible
use-case there, and it hasn't been asked for in any case).

Pavel Stehule
2014-09-11 21:23:51 -04:00

2403 lines
60 KiB
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/*-------------------------------------------------------------------------
*
* json.c
* JSON data type support.
*
* Portions Copyright (c) 1996-2014, 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 "miscadmin.h"
#include "parser/parse_coerce.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/date.h"
#include "utils/datetime.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;
typedef enum /* type categories for datum_to_json */
{
JSONTYPE_NULL, /* null, so we didn't bother to identify */
JSONTYPE_BOOL, /* boolean (built-in types only) */
JSONTYPE_NUMERIC, /* numeric (ditto) */
JSONTYPE_DATE, /* we use special formatting for datetimes */
JSONTYPE_TIMESTAMP,
JSONTYPE_TIMESTAMPTZ,
JSONTYPE_JSON, /* JSON itself (and JSONB) */
JSONTYPE_ARRAY, /* array */
JSONTYPE_COMPOSITE, /* composite */
JSONTYPE_CAST, /* something with an explicit cast to JSON */
JSONTYPE_OTHER /* all else */
} JsonTypeCategory;
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, bool *num_err);
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,
bool ignore_nulls);
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);
static void array_to_json_internal(Datum array, StringInfo result,
bool use_line_feeds);
static void json_categorize_type(Oid typoid,
JsonTypeCategory *tcategory,
Oid *outfuncoid);
static void datum_to_json(Datum val, bool is_null, StringInfo result,
JsonTypeCategory tcategory, Oid outfuncoid,
bool key_scalar);
static void add_json(Datum val, bool is_null, StringInfo result,
Oid val_type, bool key_scalar);
/* 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);;
}
/* 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);
char *str;
int nbytes;
JsonLexContext *lex;
str = pq_getmsgtext(buf, buf->len - buf->cursor, &nbytes);
/* Validate it. */
lex = makeJsonLexContextCstringLen(str, nbytes, false);
pg_parse_json(lex, &nullSemAction);
PG_RETURN_TEXT_P(cstring_to_text_with_len(str, nbytes));
}
/*
* 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.
*
* If you already have the json as a text* value, use the first of these
* functions, otherwise use makeJsonLexContextCstringLen().
*/
JsonLexContext *
makeJsonLexContext(text *json, bool need_escapes)
{
return makeJsonLexContextCstringLen(VARDATA(json),
VARSIZE(json) - VARHDRSZ,
need_escapes);
}
JsonLexContext *
makeJsonLexContextCstringLen(char *json, int len, bool need_escapes)
{
JsonLexContext *lex = palloc0(sizeof(JsonLexContext));
lex->input = lex->token_terminator = lex->line_start = json;
lex->line_number = 1;
lex->input_length = len;
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. Note: in user-facing docs and error messages, we
* generally call a field name a "key".
*/
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);
}
static void
parse_object(JsonLexContext *lex, JsonSemAction *sem)
{
/*
* an object is a possibly empty sequence of object fields, separated by
* commas and surrounded 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 is 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 is 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, NULL);
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, NULL);
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 *num_err)
{
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;
if (num_err != NULL)
{
/* let the caller handle the error */
*num_err = error;
}
else
{
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;
}
/*
* Determine how we want to print values of a given type in datum_to_json.
*
* Given the datatype OID, return its JsonTypeCategory, as well as the type's
* output function OID. If the returned category is JSONTYPE_CAST, we
* return the OID of the type->JSON cast function instead.
*/
static void
json_categorize_type(Oid typoid,
JsonTypeCategory *tcategory,
Oid *outfuncoid)
{
bool typisvarlena;
/* Look through any domain */
typoid = getBaseType(typoid);
/* We'll usually need to return the type output function */
getTypeOutputInfo(typoid, outfuncoid, &typisvarlena);
/* Check for known types */
switch (typoid)
{
case BOOLOID:
*tcategory = JSONTYPE_BOOL;
break;
case INT2OID:
case INT4OID:
case INT8OID:
case FLOAT4OID:
case FLOAT8OID:
case NUMERICOID:
*tcategory = JSONTYPE_NUMERIC;
break;
case DATEOID:
*tcategory = JSONTYPE_DATE;
break;
case TIMESTAMPOID:
*tcategory = JSONTYPE_TIMESTAMP;
break;
case TIMESTAMPTZOID:
*tcategory = JSONTYPE_TIMESTAMPTZ;
break;
case JSONOID:
case JSONBOID:
*tcategory = JSONTYPE_JSON;
break;
default:
/* Check for arrays and composites */
if (OidIsValid(get_element_type(typoid)))
*tcategory = JSONTYPE_ARRAY;
else if (type_is_rowtype(typoid))
*tcategory = JSONTYPE_COMPOSITE;
else
{
/* It's probably the general case ... */
*tcategory = JSONTYPE_OTHER;
/* but let's look for a cast to json, if it's not built-in */
if (typoid >= FirstNormalObjectId)
{
HeapTuple tuple;
tuple = SearchSysCache2(CASTSOURCETARGET,
ObjectIdGetDatum(typoid),
ObjectIdGetDatum(JSONOID));
if (HeapTupleIsValid(tuple))
{
Form_pg_cast castForm = (Form_pg_cast) GETSTRUCT(tuple);
if (castForm->castmethod == COERCION_METHOD_FUNCTION)
{
*tcategory = JSONTYPE_CAST;
*outfuncoid = castForm->castfunc;
}
ReleaseSysCache(tuple);
}
}
}
break;
}
}
/*
* Turn a Datum into JSON text, appending the string to "result".
*
* tcategory and outfuncoid are from a previous call to json_categorize_type,
* except that if is_null is true then they can be invalid.
*
* If key_scalar is true, the value is being printed as a key, so insist
* it's of an acceptable type, and force it to be quoted.
*/
static void
datum_to_json(Datum val, bool is_null, StringInfo result,
JsonTypeCategory tcategory, Oid outfuncoid,
bool key_scalar)
{
char *outputstr;
text *jsontext;
bool numeric_error;
JsonLexContext dummy_lex;
if (is_null)
{
appendStringInfoString(result, "null");
return;
}
if (key_scalar &&
(tcategory == JSONTYPE_ARRAY ||
tcategory == JSONTYPE_COMPOSITE ||
tcategory == JSONTYPE_JSON ||
tcategory == JSONTYPE_CAST))
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("key value must be scalar, not array, composite, or json")));
switch (tcategory)
{
case JSONTYPE_ARRAY:
array_to_json_internal(val, result, false);
break;
case JSONTYPE_COMPOSITE:
composite_to_json(val, result, false, false);
break;
case JSONTYPE_BOOL:
outputstr = DatumGetBool(val) ? "true" : "false";
if (key_scalar)
escape_json(result, outputstr);
else
appendStringInfoString(result, outputstr);
break;
case JSONTYPE_NUMERIC:
outputstr = OidOutputFunctionCall(outfuncoid, val);
if (key_scalar)
{
/* always quote keys */
escape_json(result, outputstr);
}
else
{
/*
* Don't call escape_json for a non-key if it's a valid JSON
* number.
*/
dummy_lex.input = *outputstr == '-' ? outputstr + 1 : outputstr;
dummy_lex.input_length = strlen(dummy_lex.input);
json_lex_number(&dummy_lex, dummy_lex.input, &numeric_error);
if (!numeric_error)
appendStringInfoString(result, outputstr);
else
escape_json(result, outputstr);
}
pfree(outputstr);
break;
case JSONTYPE_DATE:
{
DateADT date;
struct pg_tm tm;
char buf[MAXDATELEN + 1];
date = DatumGetDateADT(val);
/* XSD doesn't support infinite values */
if (DATE_NOT_FINITE(date))
ereport(ERROR,
(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
errmsg("date out of range"),
errdetail("JSON does not support infinite date values.")));
else
{
j2date(date + POSTGRES_EPOCH_JDATE,
&(tm.tm_year), &(tm.tm_mon), &(tm.tm_mday));
EncodeDateOnly(&tm, USE_XSD_DATES, buf);
}
appendStringInfo(result, "\"%s\"", buf);
}
break;
case JSONTYPE_TIMESTAMP:
{
Timestamp timestamp;
struct pg_tm tm;
fsec_t fsec;
char buf[MAXDATELEN + 1];
timestamp = DatumGetTimestamp(val);
/* XSD doesn't support infinite values */
if (TIMESTAMP_NOT_FINITE(timestamp))
ereport(ERROR,
(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
errmsg("timestamp out of range"),
errdetail("JSON does not support infinite timestamp values.")));
else if (timestamp2tm(timestamp, NULL, &tm, &fsec, NULL, NULL) == 0)
EncodeDateTime(&tm, fsec, false, 0, NULL, USE_XSD_DATES, buf);
else
ereport(ERROR,
(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
errmsg("timestamp out of range")));
appendStringInfo(result, "\"%s\"", buf);
}
break;
case JSONTYPE_TIMESTAMPTZ:
{
TimestampTz timestamp;
struct pg_tm tm;
int tz;
fsec_t fsec;
const char *tzn = NULL;
char buf[MAXDATELEN + 1];
timestamp = DatumGetTimestamp(val);
/* XSD doesn't support infinite values */
if (TIMESTAMP_NOT_FINITE(timestamp))
ereport(ERROR,
(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
errmsg("timestamp out of range"),
errdetail("JSON does not support infinite timestamp values.")));
else if (timestamp2tm(timestamp, &tz, &tm, &fsec, &tzn, NULL) == 0)
EncodeDateTime(&tm, fsec, true, tz, tzn, USE_XSD_DATES, buf);
else
ereport(ERROR,
(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
errmsg("timestamp out of range")));
appendStringInfo(result, "\"%s\"", buf);
}
break;
case JSONTYPE_JSON:
/* JSON and JSONB output will already be escaped */
outputstr = OidOutputFunctionCall(outfuncoid, val);
appendStringInfoString(result, outputstr);
pfree(outputstr);
break;
case JSONTYPE_CAST:
/* outfuncoid refers to a cast function, not an output function */
jsontext = DatumGetTextP(OidFunctionCall1(outfuncoid, val));
outputstr = text_to_cstring(jsontext);
appendStringInfoString(result, outputstr);
pfree(outputstr);
pfree(jsontext);
break;
default:
outputstr = OidOutputFunctionCall(outfuncoid, val);
if (key_scalar && *outputstr == '\0')
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("key value must not be empty")));
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, JsonTypeCategory tcategory,
Oid outfuncoid, 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,
outfuncoid, false);
(*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, outfuncoid, 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;
JsonTypeCategory tcategory;
Oid outfuncoid;
ndim = ARR_NDIM(v);
dim = ARR_DIMS(v);
nitems = ArrayGetNItems(ndim, dim);
if (nitems <= 0)
{
appendStringInfoString(result, "[]");
return;
}
get_typlenbyvalalign(element_type,
&typlen, &typbyval, &typalign);
json_categorize_type(element_type,
&tcategory, &outfuncoid);
deconstruct_array(v, element_type, typlen, typbyval,
typalign, &elements, &nulls,
&nitems);
array_dim_to_json(result, 0, ndim, dim, elements, nulls, &count, tcategory,
outfuncoid, 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,
bool ignore_nulls)
{
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;
bool isnull;
char *attname;
JsonTypeCategory tcategory;
Oid outfuncoid;
if (tupdesc->attrs[i]->attisdropped)
continue;
val = heap_getattr(tuple, i + 1, tupdesc, &isnull);
/* Don't serialize NULL field when we don't want it */
if (isnull && ignore_nulls)
continue;
if (needsep)
appendStringInfoString(result, sep);
needsep = true;
attname = NameStr(tupdesc->attrs[i]->attname);
escape_json(result, attname);
appendStringInfoChar(result, ':');
if (isnull)
{
tcategory = JSONTYPE_NULL;
outfuncoid = InvalidOid;
}
else
json_categorize_type(tupdesc->attrs[i]->atttypid,
&tcategory, &outfuncoid);
datum_to_json(val, isnull, result, tcategory, outfuncoid, false);
}
appendStringInfoChar(result, '}');
ReleaseTupleDesc(tupdesc);
}
/*
* Append JSON text for "val" to "result".
*
* This is just a thin wrapper around datum_to_json. If the same type will be
* printed many times, avoid using this; better to do the json_categorize_type
* lookups only once.
*/
static void
add_json(Datum val, bool is_null, StringInfo result,
Oid val_type, bool key_scalar)
{
JsonTypeCategory tcategory;
Oid outfuncoid;
if (val_type == InvalidOid)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("could not determine input data type")));
if (is_null)
{
tcategory = JSONTYPE_NULL;
outfuncoid = InvalidOid;
}
else
json_categorize_type(val_type,
&tcategory, &outfuncoid);
datum_to_json(val, is_null, result, tcategory, outfuncoid, key_scalar);
}
/*
* SQL function array_to_json(row, prettybool)
*/
extern Datum
array_to_json(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_with_len(result->data, result->len));
}
/*
* SQL function row_to_json(rowval record, pretty bool, ignore_nulls bool)
*/
extern Datum
row_to_json(PG_FUNCTION_ARGS)
{
Datum array = PG_GETARG_DATUM(0);
bool use_line_feeds = PG_GETARG_BOOL(1);
bool ignore_nulls = PG_GETARG_BOOL(2);
StringInfo result;
result = makeStringInfo();
composite_to_json(array, result, use_line_feeds, ignore_nulls);
PG_RETURN_TEXT_P(cstring_to_text_with_len(result->data, result->len));
}
/*
* SQL function to_json(anyvalue)
*/
Datum
to_json(PG_FUNCTION_ARGS)
{
Datum val = PG_GETARG_DATUM(0);
Oid val_type = get_fn_expr_argtype(fcinfo->flinfo, 0);
StringInfo result;
JsonTypeCategory tcategory;
Oid outfuncoid;
if (val_type == InvalidOid)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("could not determine input data type")));
json_categorize_type(val_type,
&tcategory, &outfuncoid);
result = makeStringInfo();
datum_to_json(val, false, result, tcategory, outfuncoid, false);
PG_RETURN_TEXT_P(cstring_to_text_with_len(result->data, result->len));
}
/*
* 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 val;
JsonTypeCategory tcategory;
Oid outfuncoid;
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 of the aggregate call. MemoryContextSwitchTo is only
* needed the first time, 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))
{
datum_to_json((Datum) 0, true, state, JSONTYPE_NULL, InvalidOid, false);
PG_RETURN_POINTER(state);
}
val = PG_GETARG_DATUM(1);
/* XXX we do this every time?? */
json_categorize_type(val_type,
&tcategory, &outfuncoid);
/* add some whitespace if structured type and not first item */
if (!PG_ARGISNULL(0) &&
(tcategory == JSONTYPE_ARRAY || tcategory == JSONTYPE_COMPOSITE))
{
appendStringInfoString(state, "\n ");
}
datum_to_json(val, false, state, tcategory, outfuncoid, false);
/*
* 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_with_len(state->data, state->len));
}
/*
* json_object_agg transition function.
*
* aggregate two input columns as a single json value.
*/
Datum
json_object_agg_transfn(PG_FUNCTION_ARGS)
{
Oid val_type;
MemoryContext aggcontext,
oldcontext;
StringInfo state;
Datum arg;
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 the StringInfo in a context where it will persist for the
* duration of the aggregate call. Switching context is only needed
* for this initial step, as the StringInfo routines make sure they
* use the right context to enlarge the object if necessary.
*/
oldcontext = MemoryContextSwitchTo(aggcontext);
state = makeStringInfo();
MemoryContextSwitchTo(oldcontext);
appendStringInfoString(state, "{ ");
}
else
{
state = (StringInfo) PG_GETARG_POINTER(0);
appendStringInfoString(state, ", ");
}
/*
* Note: since json_object_agg() is declared as taking type "any", the
* parser will not do any type conversion on unknown-type literals (that
* is, undecorated strings or NULLs). Such values will arrive here as
* type UNKNOWN, which fortunately does not matter to us, since
* unknownout() works fine.
*/
val_type = get_fn_expr_argtype(fcinfo->flinfo, 1);
if (val_type == InvalidOid)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("could not determine data type for argument %d", 1)));
if (PG_ARGISNULL(1))
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("field name must not be null")));
arg = PG_GETARG_DATUM(1);
add_json(arg, false, state, val_type, true);
appendStringInfoString(state, " : ");
val_type = get_fn_expr_argtype(fcinfo->flinfo, 2);
if (val_type == InvalidOid)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("could not determine data type for argument %d", 2)));
if (PG_ARGISNULL(2))
arg = (Datum) 0;
else
arg = PG_GETARG_DATUM(2);
add_json(arg, PG_ARGISNULL(2), state, val_type, false);
PG_RETURN_POINTER(state);
}
/*
* json_object_agg final function.
*
*/
Datum
json_object_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_TEXT_P(cstring_to_text("{}"));
appendStringInfoString(state, " }");
PG_RETURN_TEXT_P(cstring_to_text_with_len(state->data, state->len));
}
/*
* SQL function json_build_object(variadic "any")
*/
Datum
json_build_object(PG_FUNCTION_ARGS)
{
int nargs = PG_NARGS();
int i;
Datum arg;
const char *sep = "";
StringInfo result;
Oid val_type;
if (nargs % 2 != 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("argument list must have even number of elements"),
errhint("The arguments of json_build_object() must consist of alternating keys and values.")));
result = makeStringInfo();
appendStringInfoChar(result, '{');
for (i = 0; i < nargs; i += 2)
{
/*
* Note: since json_build_object() is declared as taking type "any",
* the parser will not do any type conversion on unknown-type literals
* (that is, undecorated strings or NULLs). Such values will arrive
* here as type UNKNOWN, which fortunately does not matter to us,
* since unknownout() works fine.
*/
appendStringInfoString(result, sep);
sep = ", ";
/* process key */
val_type = get_fn_expr_argtype(fcinfo->flinfo, i);
if (val_type == InvalidOid)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("could not determine data type for argument %d",
i + 1)));
if (PG_ARGISNULL(i))
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("argument %d cannot be null", i + 1),
errhint("Object keys should be text.")));
arg = PG_GETARG_DATUM(i);
add_json(arg, false, result, val_type, true);
appendStringInfoString(result, " : ");
/* process value */
val_type = get_fn_expr_argtype(fcinfo->flinfo, i + 1);
if (val_type == InvalidOid)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("could not determine data type for argument %d",
i + 2)));
if (PG_ARGISNULL(i + 1))
arg = (Datum) 0;
else
arg = PG_GETARG_DATUM(i + 1);
add_json(arg, PG_ARGISNULL(i + 1), result, val_type, false);
}
appendStringInfoChar(result, '}');
PG_RETURN_TEXT_P(cstring_to_text_with_len(result->data, result->len));
}
/*
* degenerate case of json_build_object where it gets 0 arguments.
*/
Datum
json_build_object_noargs(PG_FUNCTION_ARGS)
{
PG_RETURN_TEXT_P(cstring_to_text_with_len("{}", 2));
}
/*
* SQL function json_build_array(variadic "any")
*/
Datum
json_build_array(PG_FUNCTION_ARGS)
{
int nargs = PG_NARGS();
int i;
Datum arg;
const char *sep = "";
StringInfo result;
Oid val_type;
result = makeStringInfo();
appendStringInfoChar(result, '[');
for (i = 0; i < nargs; i++)
{
/*
* Note: since json_build_array() is declared as taking type "any",
* the parser will not do any type conversion on unknown-type literals
* (that is, undecorated strings or NULLs). Such values will arrive
* here as type UNKNOWN, which fortunately does not matter to us,
* since unknownout() works fine.
*/
appendStringInfoString(result, sep);
sep = ", ";
val_type = get_fn_expr_argtype(fcinfo->flinfo, i);
if (val_type == InvalidOid)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("could not determine data type for argument %d",
i + 1)));
if (PG_ARGISNULL(i))
arg = (Datum) 0;
else
arg = PG_GETARG_DATUM(i);
add_json(arg, PG_ARGISNULL(i), result, val_type, false);
}
appendStringInfoChar(result, ']');
PG_RETURN_TEXT_P(cstring_to_text_with_len(result->data, result->len));
}
/*
* degenerate case of json_build_array where it gets 0 arguments.
*/
Datum
json_build_array_noargs(PG_FUNCTION_ARGS)
{
PG_RETURN_TEXT_P(cstring_to_text_with_len("[]", 2));
}
/*
* SQL function json_object(text[])
*
* take a one or two dimensional array of text as key/value pairs
* for a json object.
*/
Datum
json_object(PG_FUNCTION_ARGS)
{
ArrayType *in_array = PG_GETARG_ARRAYTYPE_P(0);
int ndims = ARR_NDIM(in_array);
StringInfoData result;
Datum *in_datums;
bool *in_nulls;
int in_count,
count,
i;
text *rval;
char *v;
switch (ndims)
{
case 0:
PG_RETURN_DATUM(CStringGetTextDatum("{}"));
break;
case 1:
if ((ARR_DIMS(in_array)[0]) % 2)
ereport(ERROR,
(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
errmsg("array must have even number of elements")));
break;
case 2:
if ((ARR_DIMS(in_array)[1]) != 2)
ereport(ERROR,
(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
errmsg("array must have two columns")));
break;
default:
ereport(ERROR,
(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
errmsg("wrong number of array subscripts")));
}
deconstruct_array(in_array,
TEXTOID, -1, false, 'i',
&in_datums, &in_nulls, &in_count);
count = in_count / 2;
initStringInfo(&result);
appendStringInfoChar(&result, '{');
for (i = 0; i < count; ++i)
{
if (in_nulls[i * 2])
ereport(ERROR,
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("null value not allowed for object key")));
v = TextDatumGetCString(in_datums[i * 2]);
if (i > 0)
appendStringInfoString(&result, ", ");
escape_json(&result, v);
appendStringInfoString(&result, " : ");
pfree(v);
if (in_nulls[i * 2 + 1])
appendStringInfoString(&result, "null");
else
{
v = TextDatumGetCString(in_datums[i * 2 + 1]);
escape_json(&result, v);
pfree(v);
}
}
appendStringInfoChar(&result, '}');
pfree(in_datums);
pfree(in_nulls);
rval = cstring_to_text_with_len(result.data, result.len);
pfree(result.data);
PG_RETURN_TEXT_P(rval);
}
/*
* SQL function json_object(text[], text[])
*
* take separate key and value arrays of text to construct a json object
* pairwise.
*/
Datum
json_object_two_arg(PG_FUNCTION_ARGS)
{
ArrayType *key_array = PG_GETARG_ARRAYTYPE_P(0);
ArrayType *val_array = PG_GETARG_ARRAYTYPE_P(1);
int nkdims = ARR_NDIM(key_array);
int nvdims = ARR_NDIM(val_array);
StringInfoData result;
Datum *key_datums,
*val_datums;
bool *key_nulls,
*val_nulls;
int key_count,
val_count,
i;
text *rval;
char *v;
if (nkdims > 1 || nkdims != nvdims)
ereport(ERROR,
(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
errmsg("wrong number of array subscripts")));
if (nkdims == 0)
PG_RETURN_DATUM(CStringGetTextDatum("{}"));
deconstruct_array(key_array,
TEXTOID, -1, false, 'i',
&key_datums, &key_nulls, &key_count);
deconstruct_array(val_array,
TEXTOID, -1, false, 'i',
&val_datums, &val_nulls, &val_count);
if (key_count != val_count)
ereport(ERROR,
(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
errmsg("mismatched array dimensions")));
initStringInfo(&result);
appendStringInfoChar(&result, '{');
for (i = 0; i < key_count; ++i)
{
if (key_nulls[i])
ereport(ERROR,
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("null value not allowed for object key")));
v = TextDatumGetCString(key_datums[i]);
if (i > 0)
appendStringInfoString(&result, ", ");
escape_json(&result, v);
appendStringInfoString(&result, " : ");
pfree(v);
if (val_nulls[i])
appendStringInfoString(&result, "null");
else
{
v = TextDatumGetCString(val_datums[i]);
escape_json(&result, v);
pfree(v);
}
}
appendStringInfoChar(&result, '}');
pfree(key_datums);
pfree(key_nulls);
pfree(val_datums);
pfree(val_nulls);
rval = cstring_to_text_with_len(result.data, result.len);
pfree(result.data);
PG_RETURN_TEXT_P(rval);
}
/*
* 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 '\\':
/*
* Unicode escapes are passed through as is. There is no
* requirement that they denote a valid character in the
* server encoding - indeed that is a big part of their
* usefulness.
*
* All we require is that they consist of \uXXXX where the Xs
* are hexadecimal digits. It is the responsibility of the
* caller of, say, to_json() to make sure that the unicode
* escape is valid.
*
* In the case of a jsonb string value being escaped, the only
* unicode escape that should be present is \u0000, all the
* other unicode escapes will have been resolved.
*/
if (p[1] == 'u' &&
isxdigit((unsigned char) p[2]) &&
isxdigit((unsigned char) p[3]) &&
isxdigit((unsigned char) p[4]) &&
isxdigit((unsigned char) p[5]))
appendStringInfoCharMacro(buf, *p);
else
appendStringInfoString(buf, "\\\\");
break;
default:
if ((unsigned char) *p < ' ')
appendStringInfo(buf, "\\u%04x", (int) *p);
else
appendStringInfoCharMacro(buf, *p);
break;
}
}
appendStringInfoCharMacro(buf, '\"');
}
/*
* SQL function json_typeof(json) -> text
*
* Returns the type of the outermost JSON value as TEXT. Possible types are
* "object", "array", "string", "number", "boolean", and "null".
*
* Performs a single call to json_lex() to get the first token of the supplied
* value. This initial token uniquely determines the value's type. As our
* input must already have been validated by json_in() or json_recv(), the
* initial token should never be JSON_TOKEN_OBJECT_END, JSON_TOKEN_ARRAY_END,
* JSON_TOKEN_COLON, JSON_TOKEN_COMMA, or JSON_TOKEN_END.
*/
Datum
json_typeof(PG_FUNCTION_ARGS)
{
text *json;
JsonLexContext *lex;
JsonTokenType tok;
char *type;
json = PG_GETARG_TEXT_P(0);
lex = makeJsonLexContext(json, false);
/* Lex exactly one token from the input and check its type. */
json_lex(lex);
tok = lex_peek(lex);
switch (tok)
{
case JSON_TOKEN_OBJECT_START:
type = "object";
break;
case JSON_TOKEN_ARRAY_START:
type = "array";
break;
case JSON_TOKEN_STRING:
type = "string";
break;
case JSON_TOKEN_NUMBER:
type = "number";
break;
case JSON_TOKEN_TRUE:
case JSON_TOKEN_FALSE:
type = "boolean";
break;
case JSON_TOKEN_NULL:
type = "null";
break;
default:
elog(ERROR, "unexpected json token: %d", tok);
}
PG_RETURN_TEXT_P(cstring_to_text(type));
}
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