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postgresql/src/backend/utils/adt/json.c

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/*-------------------------------------------------------------------------
*
* json.c
* JSON data type support.
*
* Portions Copyright (c) 1996-2022, 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/hash.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "common/hashfn.h"
#include "funcapi.h"
#include "libpq/pqformat.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/json.h"
#include "utils/jsonfuncs.h"
#include "utils/lsyscache.h"
#include "utils/typcache.h"
/* Common context for key uniqueness check */
typedef struct HTAB *JsonUniqueCheckState; /* hash table for key names */
/* Hash entry for JsonUniqueCheckState */
typedef struct JsonUniqueHashEntry
{
const char *key;
int key_len;
int object_id;
} JsonUniqueHashEntry;
/* Context for key uniqueness check in builder functions */
typedef struct JsonUniqueBuilderState
{
JsonUniqueCheckState check; /* unique check */
StringInfoData skipped_keys; /* skipped keys with NULL values */
MemoryContext mcxt; /* context for saving skipped keys */
} JsonUniqueBuilderState;
/* Element of object stack for key uniqueness check during json parsing */
typedef struct JsonUniqueStackEntry
{
struct JsonUniqueStackEntry *parent;
int object_id;
} JsonUniqueStackEntry;
/* State for key uniqueness check during json parsing */
typedef struct JsonUniqueParsingState
{
JsonLexContext *lex;
JsonUniqueCheckState check;
JsonUniqueStackEntry *stack;
int id_counter;
bool unique;
} JsonUniqueParsingState;
typedef struct JsonAggState
{
StringInfo str;
JsonTypeCategory key_category;
Oid key_output_func;
JsonTypeCategory val_category;
Oid val_output_func;
JsonUniqueBuilderState unique_check;
} JsonAggState;
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,
JsonTypeCategory tcategory, Oid outfuncoid,
bool use_line_feeds);
static void array_to_json_internal(Datum array, StringInfo result,
bool use_line_feeds);
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);
static text *catenate_stringinfo_string(StringInfo buffer, const char *addon);
/*
* 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_or_ereport(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, GetDatabaseEncoding(), false);
pg_parse_json_or_ereport(lex, &nullSemAction);
PG_RETURN_TEXT_P(cstring_to_text_with_len(str, nbytes));
}
/*
* 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.
*/
void
json_categorize_type(Oid typoid,
JsonTypeCategory *tcategory,
Oid *outfuncoid)
{
bool typisvarlena;
/* Look through any domain */
typoid = getBaseType(typoid);
*outfuncoid = InvalidOid;
/*
* We need to get the output function for everything except date and
* timestamp types, array and composite types, booleans, and non-builtin
* types where there's a cast to json.
*/
switch (typoid)
{
case BOOLOID:
*tcategory = JSONTYPE_BOOL;
break;
case INT2OID:
case INT4OID:
case INT8OID:
case FLOAT4OID:
case FLOAT8OID:
case NUMERICOID:
getTypeOutputInfo(typoid, outfuncoid, &typisvarlena);
*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:
getTypeOutputInfo(typoid, outfuncoid, &typisvarlena);
*tcategory = JSONTYPE_JSON;
break;
default:
/* Check for arrays and composites */
if (OidIsValid(get_element_type(typoid)) || typoid == ANYARRAYOID
|| typoid == ANYCOMPATIBLEARRAYOID || typoid == RECORDARRAYOID)
*tcategory = JSONTYPE_ARRAY;
else if (type_is_rowtype(typoid)) /* includes RECORDOID */
*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)
{
Oid castfunc;
CoercionPathType ctype;
ctype = find_coercion_pathway(JSONOID, typoid,
COERCION_EXPLICIT,
&castfunc);
if (ctype == COERCION_PATH_FUNC && OidIsValid(castfunc))
{
*tcategory = JSONTYPE_CAST;
*outfuncoid = castfunc;
}
else
{
/* non builtin type with no cast */
getTypeOutputInfo(typoid, outfuncoid, &typisvarlena);
}
}
else
{
/* any other builtin type */
getTypeOutputInfo(typoid, outfuncoid, &typisvarlena);
}
}
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;
check_stack_depth();
/* callers are expected to ensure that null keys are not passed in */
Assert(!(key_scalar && is_null));
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);
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);
/*
* Don't call escape_json for a non-key if it's a valid JSON
* number.
*/
if (!key_scalar && IsValidJsonNumber(outputstr, strlen(outputstr)))
appendStringInfoString(result, outputstr);
else
escape_json(result, outputstr);
pfree(outputstr);
break;
case JSONTYPE_DATE:
{
char buf[MAXDATELEN + 1];
JsonEncodeDateTime(buf, val, DATEOID, NULL);
appendStringInfo(result, "\"%s\"", buf);
}
break;
case JSONTYPE_TIMESTAMP:
{
char buf[MAXDATELEN + 1];
JsonEncodeDateTime(buf, val, TIMESTAMPOID, NULL);
appendStringInfo(result, "\"%s\"", buf);
}
break;
case JSONTYPE_TIMESTAMPTZ:
{
char buf[MAXDATELEN + 1];
JsonEncodeDateTime(buf, val, TIMESTAMPTZOID, NULL);
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 = DatumGetTextPP(OidFunctionCall1(outfuncoid, val));
outputstr = text_to_cstring(jsontext);
appendStringInfoString(result, outputstr);
pfree(outputstr);
pfree(jsontext);
break;
default:
outputstr = OidOutputFunctionCall(outfuncoid, val);
escape_json(result, outputstr);
pfree(outputstr);
break;
}
}
/*
* Encode 'value' of datetime type 'typid' into JSON string in ISO format using
* optionally preallocated buffer 'buf'. Optional 'tzp' determines time-zone
* offset (in seconds) in which we want to show timestamptz.
*/
char *
JsonEncodeDateTime(char *buf, Datum value, Oid typid, const int *tzp)
{
if (!buf)
buf = palloc(MAXDATELEN + 1);
switch (typid)
{
case DATEOID:
{
DateADT date;
struct pg_tm tm;
date = DatumGetDateADT(value);
/* Same as date_out(), but forcing DateStyle */
if (DATE_NOT_FINITE(date))
EncodeSpecialDate(date, buf);
else
{
j2date(date + POSTGRES_EPOCH_JDATE,
&(tm.tm_year), &(tm.tm_mon), &(tm.tm_mday));
EncodeDateOnly(&tm, USE_XSD_DATES, buf);
}
}
break;
case TIMEOID:
{
TimeADT time = DatumGetTimeADT(value);
struct pg_tm tt,
*tm = &tt;
fsec_t fsec;
/* Same as time_out(), but forcing DateStyle */
time2tm(time, tm, &fsec);
EncodeTimeOnly(tm, fsec, false, 0, USE_XSD_DATES, buf);
}
break;
case TIMETZOID:
{
TimeTzADT *time = DatumGetTimeTzADTP(value);
struct pg_tm tt,
*tm = &tt;
fsec_t fsec;
int tz;
/* Same as timetz_out(), but forcing DateStyle */
timetz2tm(time, tm, &fsec, &tz);
EncodeTimeOnly(tm, fsec, true, tz, USE_XSD_DATES, buf);
}
break;
case TIMESTAMPOID:
{
Timestamp timestamp;
struct pg_tm tm;
fsec_t fsec;
timestamp = DatumGetTimestamp(value);
/* Same as timestamp_out(), but forcing DateStyle */
if (TIMESTAMP_NOT_FINITE(timestamp))
EncodeSpecialTimestamp(timestamp, buf);
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")));
}
break;
case TIMESTAMPTZOID:
{
TimestampTz timestamp;
struct pg_tm tm;
int tz;
fsec_t fsec;
const char *tzn = NULL;
timestamp = DatumGetTimestampTz(value);
/*
* If a time zone is specified, we apply the time-zone shift,
* convert timestamptz to pg_tm as if it were without a time
* zone, and then use the specified time zone for converting
* the timestamp into a string.
*/
if (tzp)
{
tz = *tzp;
timestamp -= (TimestampTz) tz * USECS_PER_SEC;
}
/* Same as timestamptz_out(), but forcing DateStyle */
if (TIMESTAMP_NOT_FINITE(timestamp))
EncodeSpecialTimestamp(timestamp, buf);
else if (timestamp2tm(timestamp, tzp ? NULL : &tz, &tm, &fsec,
tzp ? NULL : &tzn, NULL) == 0)
{
if (tzp)
tm.tm_isdst = 1; /* set time-zone presence flag */
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")));
}
break;
default:
elog(ERROR, "unknown jsonb value datetime type oid %u", typid);
return NULL;
}
return buf;
}
/*
* 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)
{
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;
Form_pg_attribute att = TupleDescAttr(tupdesc, i);
if (att->attisdropped)
continue;
if (needsep)
appendStringInfoString(result, sep);
needsep = true;
attname = NameStr(att->attname);
escape_json(result, attname);
appendStringInfoChar(result, ':');
val = heap_getattr(tuple, i + 1, tupdesc, &isnull);
if (isnull)
{
tcategory = JSONTYPE_NULL;
outfuncoid = InvalidOid;
}
else
json_categorize_type(att->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)
*/
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_with_len(result->data, result->len));
}
/*
* SQL function array_to_json(row, prettybool)
*/
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_with_len(result->data, result->len));
}
/*
* SQL function row_to_json(row)
*/
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_with_len(result->data, result->len));
}
/*
* SQL function row_to_json(row, prettybool)
*/
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_with_len(result->data, result->len));
}
Datum
to_json_worker(Datum val, JsonTypeCategory tcategory, Oid outfuncoid)
{
StringInfo result = makeStringInfo();
datum_to_json(val, false, result, tcategory, outfuncoid, false);
return PointerGetDatum(cstring_to_text_with_len(result->data, result->len));
}
bool
to_json_is_immutable(Oid typoid)
{
JsonTypeCategory tcategory;
Oid outfuncoid;
json_categorize_type(typoid, &tcategory, &outfuncoid);
switch (tcategory)
{
case JSONTYPE_BOOL:
case JSONTYPE_JSON:
return true;
case JSONTYPE_DATE:
case JSONTYPE_TIMESTAMP:
case JSONTYPE_TIMESTAMPTZ:
return false;
case JSONTYPE_ARRAY:
return false; /* TODO recurse into elements */
case JSONTYPE_COMPOSITE:
return false; /* TODO recurse into fields */
case JSONTYPE_NUMERIC:
case JSONTYPE_CAST:
default:
return func_volatile(outfuncoid) == PROVOLATILE_IMMUTABLE;
}
}
/*
* 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);
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);
PG_RETURN_DATUM(to_json_worker(val, tcategory, outfuncoid));
}
/*
* json_agg transition function
*
* aggregate input column as a json array value.
*/
static Datum
json_agg_transfn_worker(FunctionCallInfo fcinfo, bool absent_on_null)
{
MemoryContext aggcontext,
oldcontext;
JsonAggState *state;
Datum val;
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))
{
Oid arg_type = get_fn_expr_argtype(fcinfo->flinfo, 1);
if (arg_type == InvalidOid)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("could not determine input data type")));
/*
* Make this state object 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 = (JsonAggState *) palloc(sizeof(JsonAggState));
state->str = makeStringInfo();
MemoryContextSwitchTo(oldcontext);
appendStringInfoChar(state->str, '[');
json_categorize_type(arg_type, &state->val_category,
&state->val_output_func);
}
else
{
state = (JsonAggState *) PG_GETARG_POINTER(0);
}
if (absent_on_null && PG_ARGISNULL(1))
PG_RETURN_POINTER(state);
if (state->str->len > 1)
appendStringInfoString(state->str, ", ");
/* fast path for NULLs */
if (PG_ARGISNULL(1))
{
datum_to_json((Datum) 0, true, state->str, JSONTYPE_NULL,
InvalidOid, false);
PG_RETURN_POINTER(state);
}
val = PG_GETARG_DATUM(1);
/* add some whitespace if structured type and not first item */
if (!PG_ARGISNULL(0) && state->str->len > 1 &&
(state->val_category == JSONTYPE_ARRAY ||
state->val_category == JSONTYPE_COMPOSITE))
{
appendStringInfoString(state->str, "\n ");
}
datum_to_json(val, false, state->str, state->val_category,
state->val_output_func, false);
/*
* The transition type for json_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 JsonAggState pointer through nodeAgg.c's machinations.
*/
PG_RETURN_POINTER(state);
}
/*
* json_agg aggregate function
*/
Datum
json_agg_transfn(PG_FUNCTION_ARGS)
{
return json_agg_transfn_worker(fcinfo, false);
}
/*
* json_agg_strict aggregate function
*/
Datum
json_agg_strict_transfn(PG_FUNCTION_ARGS)
{
return json_agg_transfn_worker(fcinfo, true);
}
/*
* json_agg final function
*/
Datum
json_agg_finalfn(PG_FUNCTION_ARGS)
{
JsonAggState *state;
/* cannot be called directly because of internal-type argument */
Assert(AggCheckCallContext(fcinfo, NULL));
state = PG_ARGISNULL(0) ?
NULL :
(JsonAggState *) PG_GETARG_POINTER(0);
/* NULL result for no rows in, as is standard with aggregates */
if (state == NULL)
PG_RETURN_NULL();
/* Else return state with appropriate array terminator added */
PG_RETURN_TEXT_P(catenate_stringinfo_string(state->str, "]"));
}
/* Functions implementing hash table for key uniqueness check */
static uint32
json_unique_hash(const void *key, Size keysize)
{
const JsonUniqueHashEntry *entry = (JsonUniqueHashEntry *) key;
uint32 hash = hash_bytes_uint32(entry->object_id);
hash ^= hash_bytes((const unsigned char *) entry->key, entry->key_len);
return DatumGetUInt32(hash);
}
static int
json_unique_hash_match(const void *key1, const void *key2, Size keysize)
{
const JsonUniqueHashEntry *entry1 = (const JsonUniqueHashEntry *) key1;
const JsonUniqueHashEntry *entry2 = (const JsonUniqueHashEntry *) key2;
if (entry1->object_id != entry2->object_id)
return entry1->object_id > entry2->object_id ? 1 : -1;
if (entry1->key_len != entry2->key_len)
return entry1->key_len > entry2->key_len ? 1 : -1;
return strncmp(entry1->key, entry2->key, entry1->key_len);
}
/* Functions implementing object key uniqueness check */
static void
json_unique_check_init(JsonUniqueCheckState *cxt)
{
HASHCTL ctl;
memset(&ctl, 0, sizeof(ctl));
ctl.keysize = sizeof(JsonUniqueHashEntry);
ctl.entrysize = sizeof(JsonUniqueHashEntry);
ctl.hcxt = CurrentMemoryContext;
ctl.hash = json_unique_hash;
ctl.match = json_unique_hash_match;
*cxt = hash_create("json object hashtable",
32,
&ctl,
HASH_ELEM | HASH_CONTEXT | HASH_FUNCTION | HASH_COMPARE);
}
static bool
json_unique_check_key(JsonUniqueCheckState *cxt, const char *key, int object_id)
{
JsonUniqueHashEntry entry;
bool found;
entry.key = key;
entry.key_len = strlen(key);
entry.object_id = object_id;
(void) hash_search(*cxt, &entry, HASH_ENTER, &found);
return !found;
}
static void
json_unique_builder_init(JsonUniqueBuilderState *cxt)
{
json_unique_check_init(&cxt->check);
cxt->mcxt = CurrentMemoryContext;
cxt->skipped_keys.data = NULL;
}
/* On-demand initialization of skipped_keys StringInfo structure */
static StringInfo
json_unique_builder_get_skipped_keys(JsonUniqueBuilderState *cxt)
{
StringInfo out = &cxt->skipped_keys;
if (!out->data)
{
MemoryContext oldcxt = MemoryContextSwitchTo(cxt->mcxt);
initStringInfo(out);
MemoryContextSwitchTo(oldcxt);
}
return out;
}
/*
* json_object_agg transition function.
*
* aggregate two input columns as a single json object value.
*/
static Datum
json_object_agg_transfn_worker(FunctionCallInfo fcinfo,
bool absent_on_null, bool unique_keys)
{
MemoryContext aggcontext,
oldcontext;
JsonAggState *state;
StringInfo out;
Datum arg;
bool skip;
int key_offset;
if (!AggCheckCallContext(fcinfo, &aggcontext))
{
/* cannot be called directly because of internal-type argument */
elog(ERROR, "json_object_agg_transfn called in non-aggregate context");
}
if (PG_ARGISNULL(0))
{
Oid arg_type;
/*
* 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 = (JsonAggState *) palloc(sizeof(JsonAggState));
state->str = makeStringInfo();
if (unique_keys)
json_unique_builder_init(&state->unique_check);
else
memset(&state->unique_check, 0, sizeof(state->unique_check));
MemoryContextSwitchTo(oldcontext);
arg_type = get_fn_expr_argtype(fcinfo->flinfo, 1);
if (arg_type == InvalidOid)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("could not determine data type for argument %d", 1)));
json_categorize_type(arg_type, &state->key_category,
&state->key_output_func);
arg_type = get_fn_expr_argtype(fcinfo->flinfo, 2);
if (arg_type == InvalidOid)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("could not determine data type for argument %d", 2)));
json_categorize_type(arg_type, &state->val_category,
&state->val_output_func);
appendStringInfoString(state->str, "{ ");
}
else
{
state = (JsonAggState *) PG_GETARG_POINTER(0);
}
/*
* 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.
*/
if (PG_ARGISNULL(1))
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("field name must not be null")));
/* Skip null values if absent_on_null */
skip = absent_on_null && PG_ARGISNULL(2);
if (skip)
{
/* If key uniqueness check is needed we must save skipped keys */
if (!unique_keys)
PG_RETURN_POINTER(state);
out = json_unique_builder_get_skipped_keys(&state->unique_check);
}
else
{
out = state->str;
/*
* Append comma delimiter only if we have already outputted some
* fields after the initial string "{ ".
*/
if (out->len > 2)
appendStringInfoString(out, ", ");
}
arg = PG_GETARG_DATUM(1);
key_offset = out->len;
datum_to_json(arg, false, out, state->key_category,
state->key_output_func, true);
if (unique_keys)
{
const char *key = &out->data[key_offset];
if (!json_unique_check_key(&state->unique_check.check, key, 0))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_JSON_OBJECT_KEY_VALUE),
errmsg("duplicate JSON key %s", key)));
if (skip)
PG_RETURN_POINTER(state);
}
appendStringInfoString(state->str, " : ");
if (PG_ARGISNULL(2))
arg = (Datum) 0;
else
arg = PG_GETARG_DATUM(2);
datum_to_json(arg, PG_ARGISNULL(2), state->str, state->val_category,
state->val_output_func, false);
PG_RETURN_POINTER(state);
}
/*
* json_object_agg aggregate function
*/
Datum
json_object_agg_transfn(PG_FUNCTION_ARGS)
{
return json_object_agg_transfn_worker(fcinfo, false, false);
}
/*
* json_object_agg_strict aggregate function
*/
Datum
json_object_agg_strict_transfn(PG_FUNCTION_ARGS)
{
return json_object_agg_transfn_worker(fcinfo, true, false);
}
/*
* json_object_agg_unique aggregate function
*/
Datum
json_object_agg_unique_transfn(PG_FUNCTION_ARGS)
{
return json_object_agg_transfn_worker(fcinfo, false, true);
}
/*
* json_object_agg_unique_strict aggregate function
*/
Datum
json_object_agg_unique_strict_transfn(PG_FUNCTION_ARGS)
{
return json_object_agg_transfn_worker(fcinfo, true, true);
}
/*
* json_object_agg final function.
*/
Datum
json_object_agg_finalfn(PG_FUNCTION_ARGS)
{
JsonAggState *state;
/* cannot be called directly because of internal-type argument */
Assert(AggCheckCallContext(fcinfo, NULL));
state = PG_ARGISNULL(0) ? NULL : (JsonAggState *) PG_GETARG_POINTER(0);
/* NULL result for no rows in, as is standard with aggregates */
if (state == NULL)
PG_RETURN_NULL();
/* Else return state with appropriate object terminator added */
PG_RETURN_TEXT_P(catenate_stringinfo_string(state->str, " }"));
}
/*
* Helper function for aggregates: return given StringInfo's contents plus
* specified trailing string, as a text datum. We need this because aggregate
* final functions are not allowed to modify the aggregate state.
*/
static text *
catenate_stringinfo_string(StringInfo buffer, const char *addon)
{
/* custom version of cstring_to_text_with_len */
int buflen = buffer->len;
int addlen = strlen(addon);
text *result = (text *) palloc(buflen + addlen + VARHDRSZ);
SET_VARSIZE(result, buflen + addlen + VARHDRSZ);
memcpy(VARDATA(result), buffer->data, buflen);
memcpy(VARDATA(result) + buflen, addon, addlen);
return result;
}
Datum
json_build_object_worker(int nargs, Datum *args, bool *nulls, Oid *types,
bool absent_on_null, bool unique_keys)
{
int i;
const char *sep = "";
StringInfo result;
JsonUniqueBuilderState unique_check;
if (nargs % 2 != 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("argument list must have even number of elements"),
/* translator: %s is a SQL function name */
errhint("The arguments of %s must consist of alternating keys and values.",
"json_build_object()")));
result = makeStringInfo();
appendStringInfoChar(result, '{');
if (unique_keys)
json_unique_builder_init(&unique_check);
for (i = 0; i < nargs; i += 2)
{
StringInfo out;
bool skip;
int key_offset;
/* Skip null values if absent_on_null */
skip = absent_on_null && nulls[i + 1];
if (skip)
{
/* If key uniqueness check is needed we must save skipped keys */
if (!unique_keys)
continue;
out = json_unique_builder_get_skipped_keys(&unique_check);
}
else
{
appendStringInfoString(result, sep);
sep = ", ";
out = result;
}
/* process key */
if (nulls[i])
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("argument %d cannot be null", i + 1),
errhint("Object keys should be text.")));
/* save key offset before key appending */
key_offset = out->len;
add_json(args[i], false, out, types[i], true);
if (unique_keys)
{
/* check key uniqueness after key appending */
const char *key = &out->data[key_offset];
if (!json_unique_check_key(&unique_check.check, key, 0))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_JSON_OBJECT_KEY_VALUE),
errmsg("duplicate JSON key %s", key)));
if (skip)
continue;
}
appendStringInfoString(result, " : ");
/* process value */
add_json(args[i + 1], nulls[i + 1], result, types[i + 1], false);
}
appendStringInfoChar(result, '}');
return PointerGetDatum(cstring_to_text_with_len(result->data, result->len));
}
/*
* SQL function json_build_object(variadic "any")
*/
Datum
json_build_object(PG_FUNCTION_ARGS)
{
Datum *args;
bool *nulls;
Oid *types;
/* build argument values to build the object */
int nargs = extract_variadic_args(fcinfo, 0, true,
&args, &types, &nulls);
if (nargs < 0)
PG_RETURN_NULL();
PG_RETURN_DATUM(json_build_object_worker(nargs, args, nulls, types, false, false));
}
/*
* 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));
}
Datum
json_build_array_worker(int nargs, Datum *args, bool *nulls, Oid *types,
bool absent_on_null)
{
int i;
const char *sep = "";
StringInfo result;
result = makeStringInfo();
appendStringInfoChar(result, '[');
for (i = 0; i < nargs; i++)
{
if (absent_on_null && nulls[i])
continue;
appendStringInfoString(result, sep);
sep = ", ";
add_json(args[i], nulls[i], result, types[i], false);
}
appendStringInfoChar(result, ']');
return PointerGetDatum(cstring_to_text_with_len(result->data, result->len));
}
/*
* SQL function json_build_array(variadic "any")
*/
Datum
json_build_array(PG_FUNCTION_ARGS)
{
Datum *args;
bool *nulls;
Oid *types;
/* build argument values to build the object */
int nargs = extract_variadic_args(fcinfo, 0, true,
&args, &types, &nulls);
if (nargs < 0)
PG_RETURN_NULL();
PG_RETURN_DATUM(json_build_array_worker(nargs, args, nulls, types, false));
}
/*
* 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_builtin(in_array, TEXTOID, &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_builtin(key_array, TEXTOID, &key_datums, &key_nulls, &key_count);
deconstruct_array_builtin(val_array, TEXTOID, &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 '\\':
appendStringInfoString(buf, "\\\\");
break;
default:
if ((unsigned char) *p < ' ')
appendStringInfo(buf, "\\u%04x", (int) *p);
else
appendStringInfoCharMacro(buf, *p);
break;
}
}
appendStringInfoCharMacro(buf, '"');
}
/* Semantic actions for key uniqueness check */
static void
json_unique_object_start(void *_state)
{
JsonUniqueParsingState *state = _state;
JsonUniqueStackEntry *entry;
if (!state->unique)
return;
/* push object entry to stack */
entry = palloc(sizeof(*entry));
entry->object_id = state->id_counter++;
entry->parent = state->stack;
state->stack = entry;
}
static void
json_unique_object_end(void *_state)
{
JsonUniqueParsingState *state = _state;
JsonUniqueStackEntry *entry;
if (!state->unique)
return;
entry = state->stack;
state->stack = entry->parent; /* pop object from stack */
pfree(entry);
}
static void
json_unique_object_field_start(void *_state, char *field, bool isnull)
{
JsonUniqueParsingState *state = _state;
JsonUniqueStackEntry *entry;
if (!state->unique)
return;
/* find key collision in the current object */
if (json_unique_check_key(&state->check, field, state->stack->object_id))
return;
state->unique = false;
/* pop all objects entries */
while ((entry = state->stack))
{
state->stack = entry->parent;
pfree(entry);
}
}
/* Validate JSON text and additionally check key uniqueness */
bool
json_validate(text *json, bool check_unique_keys, bool throw_error)
{
JsonLexContext *lex = makeJsonLexContext(json, check_unique_keys);
JsonSemAction uniqueSemAction = {0};
JsonUniqueParsingState state;
JsonParseErrorType result;
if (check_unique_keys)
{
state.lex = lex;
state.stack = NULL;
state.id_counter = 0;
state.unique = true;
json_unique_check_init(&state.check);
uniqueSemAction.semstate = &state;
uniqueSemAction.object_start = json_unique_object_start;
uniqueSemAction.object_field_start = json_unique_object_field_start;
uniqueSemAction.object_end = json_unique_object_end;
}
result = pg_parse_json(lex, check_unique_keys ? &uniqueSemAction : &nullSemAction);
if (result != JSON_SUCCESS)
{
if (throw_error)
json_ereport_error(result, lex);
return false; /* invalid json */
}
if (check_unique_keys && !state.unique)
{
if (throw_error)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_JSON_OBJECT_KEY_VALUE),
errmsg("duplicate JSON object key value")));
return false; /* not unique keys */
}
return true; /* ok */
}
/*
* 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 = PG_GETARG_TEXT_PP(0);
char *type;
JsonTokenType tok;
/* Lex exactly one token from the input and check its type. */
tok = json_get_first_token(json, true);
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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