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/*-------------------------------------------------------------------------
*
* json_op.c
* Manipulation procedures for JSON data type.
*
* Copyright (c) 2010, PostgreSQL Global Development Group
* Written by Joey Adams <[email protected]>.
*
*-------------------------------------------------------------------------
*/
#include "json.h"
#include "jsonpath.h"
#include "util.h"
static EnumLabel enum_labels[JSON_TYPE_COUNT] =
{
{JSON_NULL, "null"},
{JSON_STRING, "string"},
{JSON_NUMBER, "number"},
{JSON_BOOL, "bool"},
{JSON_OBJECT, "object"},
{JSON_ARRAY, "array"}
};
/* json_validate(text). Renamed to avoid clashing
* with the C function json_validate. */
PG_FUNCTION_INFO_V1(json_validate_f);
Datum json_validate_f(PG_FUNCTION_ARGS);
Datum
json_validate_f(PG_FUNCTION_ARGS)
{
char *string;
bool ret;
string = text_to_utf8_cstring(PG_GETARG_JSON_P(0));
ret = json_validate(string);
pfree(string);
PG_RETURN_BOOL(ret);
}
/* json_type(json). Renamed to avoid clashing
* with the typedef enum of the same name. */
PG_FUNCTION_INFO_V1(json_get_type);
Datum json_get_type(PG_FUNCTION_ARGS);
Datum
json_get_type(PG_FUNCTION_ARGS)
{
jsontype *t = PG_GETARG_JSON_P(0);
json_type type;
Oid *label_oids;
/*
* No need to convert to UTF-8 before calling json_text_type, as it looks
* solely at ASCII characters.
*/
type = json_text_type(VARDATA_ANY(t), VARSIZE_ANY_EXHDR(t));
if (!json_type_is_valid(type))
report_corrupt_json();
label_oids = fcinfo->flinfo->fn_extra;
if (label_oids == NULL)
{
label_oids = fcinfo->flinfo->fn_extra =
MemoryContextAlloc(fcinfo->flinfo->fn_mcxt,
JSON_TYPE_COUNT * sizeof(Oid));
getEnumLabelOids("json_type", enum_labels, label_oids, JSON_TYPE_COUNT);
}
PG_RETURN_OID(label_oids[type]);
}
PG_FUNCTION_INFO_V1(json_condense);
Datum json_condense(PG_FUNCTION_ARGS);
Datum
json_condense(PG_FUNCTION_ARGS)
{
char *string;
JSON *json;
char *condensed;
string = text_to_utf8_cstring(PG_GETARG_JSON_P(0));
json = json_decode(string);
condensed = json_encode(json, 0);
if (condensed == NULL)
report_corrupt_json();
PG_RETURN_JSON_P(utf8_cstring_to_text(condensed));
}
/*
* json_path_base
* Given the function call info of a PostgreSQL function
* with arguments (JSON, jsonpath TEXT [, ...]),
* match the JSONPath string given in the second argument
* against the JSON tree given in the first argument.
*
* This returns a List of JPRef* items, just like jp_match.
* jpref_encode() is used to convert them to JSON-formatted strings.
*/
static List *
json_path_base(FunctionCallInfo fcinfo)
{
char *json_string = text_to_utf8_cstring(PG_GETARG_JSON_P(0));
char *path_string = text_to_utf8_cstring(PG_GETARG_TEXT_PP(1));
JSONPath *jpath = jp_parse(path_string);
JSON *json = json_decode(json_string);
List *result_list;
if (jpath == NULL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid JSONPath expression")));
if (json == NULL)
report_corrupt_json();
result_list = jp_match(jpath, json);
return result_list;
}
PG_FUNCTION_INFO_V1(json_get);
Datum json_get(PG_FUNCTION_ARGS);
Datum
json_get(PG_FUNCTION_ARGS)
{
List *result_list = json_path_base(fcinfo);
ListCell *result;
char *rs_json;
jsontype *result_vardata;
int length = list_length(result_list);
if (length == 0)
{
PG_RETURN_NULL();
}
else if (length == 1)
{
result = list_head(result_list);
rs_json = jpref_encode(lfirst(result));
Assert(rs_json != NULL);
Assert(json_validate(rs_json) == true);
result_vardata = (jsontype *) utf8_cstring_to_text(rs_json);
pfree(rs_json);
PG_RETURN_JSON_P(result_vardata);
}
else
{
ereport(ERROR,
(errcode(ERRCODE_DATA_EXCEPTION),
errmsg("JSONPath expression matched multiple results")));
PG_RETURN_NULL();
}
}
PG_FUNCTION_INFO_V1(json_set);
Datum json_set(PG_FUNCTION_ARGS);
Datum
json_set(PG_FUNCTION_ARGS)
{
char *json_string = text_to_utf8_cstring(PG_GETARG_JSON_P(0));
char *path_string = text_to_utf8_cstring(PG_GETARG_TEXT_PP(1));
char *rvalue_string = text_to_utf8_cstring(PG_GETARG_JSON_P(2));
JSONPath *jpath = jp_parse(path_string);
JSON *json = json_decode(json_string);
JSON *rvalue = json_decode(rvalue_string);
char *result;
jsontype *result_text;
if (jpath == NULL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid JSONPath expression")));
if (json == NULL || rvalue == NULL)
report_corrupt_json();
jp_set(jpath, json, rvalue);
result = json_encode(json, JSONOPT_USE_ORIG | JSONOPT_NO_TRIM);
result_text = utf8_cstring_to_text(result);
pfree(result);
PG_RETURN_JSON_P(result_text);
}
PG_FUNCTION_INFO_V1(json_path);
Datum json_path(PG_FUNCTION_ARGS);
Datum
json_path(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
ListCell *result;
/* TODO: consider returning the entire result set in one call. */
if (SRF_IS_FIRSTCALL())
{
MemoryContext oldcontext;
List *results;
funcctx = SRF_FIRSTCALL_INIT();
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
results = json_path_base(fcinfo);
funcctx->user_fctx = list_head(results);
MemoryContextSwitchTo(oldcontext);
}
funcctx = SRF_PERCALL_SETUP();
result = funcctx->user_fctx;
if (result != NULL)
{
char *json_string;
jsontype *json_text;
json_string = jpref_encode(lfirst(result));
Assert(json_string != NULL);
Assert(json_validate(json_string) == true);
json_text = utf8_cstring_to_text(json_string);
funcctx->user_fctx = lnext(result);
SRF_RETURN_NEXT(funcctx, JSONPGetDatum(json_text));
}
SRF_RETURN_DONE(funcctx);
}
PG_FUNCTION_INFO_V1(parse_json_path);
Datum parse_json_path(PG_FUNCTION_ARGS);
Datum
parse_json_path(PG_FUNCTION_ARGS)
{
char *string = text_to_utf8_cstring(PG_GETARG_TEXT_PP(0));
JSONPath *jpath = jp_parse(string);
char *normalized;
if (jpath == NULL)
PG_RETURN_NULL();
normalized = jp_show(jpath);
PG_RETURN_TEXT_P(utf8_cstring_to_text(normalized));
}
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