diff options
Diffstat (limited to 'src/backend/parser/parse_expr.c')
| -rw-r--r-- | src/backend/parser/parse_expr.c | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c index 1c09ea24cdf..985ddbedf11 100644 --- a/src/backend/parser/parse_expr.c +++ b/src/backend/parser/parse_expr.c @@ -34,6 +34,7 @@ #include "parser/parse_type.h" #include "utils/builtins.h" #include "utils/date.h" +#include "utils/fmgroids.h" #include "utils/lsyscache.h" #include "utils/timestamp.h" #include "utils/xml.h" @@ -3099,3 +3100,183 @@ ParseExprKindName(ParseExprKind exprKind) } return "unrecognized expression kind"; } + +/* + * Make string Const node from JSON encoding name. + * + * UTF8 is default encoding. + */ +static Const * +getJsonEncodingConst(JsonFormat *format) +{ + JsonEncoding encoding; + const char *enc; + Name encname = palloc(sizeof(NameData)); + + if (!format || + format->format_type == JS_FORMAT_DEFAULT || + format->encoding == JS_ENC_DEFAULT) + encoding = JS_ENC_UTF8; + else + encoding = format->encoding; + + switch (encoding) + { + case JS_ENC_UTF16: + enc = "UTF16"; + break; + case JS_ENC_UTF32: + enc = "UTF32"; + break; + case JS_ENC_UTF8: + enc = "UTF8"; + break; + default: + elog(ERROR, "invalid JSON encoding: %d", encoding); + break; + } + + namestrcpy(encname, enc); + + return makeConst(NAMEOID, -1, InvalidOid, NAMEDATALEN, + NameGetDatum(encname), false, false); +} + +/* + * Make bytea => text conversion using specified JSON format encoding. + */ +static Node * +makeJsonByteaToTextConversion(Node *expr, JsonFormat *format, int location) +{ + Const *encoding = getJsonEncodingConst(format); + FuncExpr *fexpr = makeFuncExpr(F_CONVERT_FROM, TEXTOID, + list_make2(expr, encoding), + InvalidOid, InvalidOid, + COERCE_EXPLICIT_CALL); + + fexpr->location = location; + + return (Node *) fexpr; +} + +/* + * Make CaseTestExpr node. + */ +static Node * +makeCaseTestExpr(Node *expr) +{ + CaseTestExpr *placeholder = makeNode(CaseTestExpr); + + placeholder->typeId = exprType(expr); + placeholder->typeMod = exprTypmod(expr); + placeholder->collation = exprCollation(expr); + + return (Node *) placeholder; +} + +/* + * Transform JSON value expression using specified input JSON format or + * default format otherwise. + */ +static Node * +transformJsonValueExpr(ParseState *pstate, JsonValueExpr *ve, + JsonFormatType default_format) +{ + Node *expr = transformExprRecurse(pstate, (Node *) ve->raw_expr); + Node *rawexpr; + JsonFormatType format; + Oid exprtype; + int location; + char typcategory; + bool typispreferred; + + if (exprType(expr) == UNKNOWNOID) + expr = coerce_to_specific_type(pstate, expr, TEXTOID, "JSON_VALUE_EXPR"); + + rawexpr = expr; + exprtype = exprType(expr); + location = exprLocation(expr); + + get_type_category_preferred(exprtype, &typcategory, &typispreferred); + + if (ve->format->format_type != JS_FORMAT_DEFAULT) + { + if (ve->format->encoding != JS_ENC_DEFAULT && exprtype != BYTEAOID) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("JSON ENCODING clause is only allowed for bytea input type"), + parser_errposition(pstate, ve->format->location))); + + if (exprtype == JSONOID || exprtype == JSONBOID) + { + format = JS_FORMAT_DEFAULT; /* do not format json[b] types */ + ereport(WARNING, + (errmsg("FORMAT JSON has no effect for json and jsonb types"), + parser_errposition(pstate, ve->format->location))); + } + else + format = ve->format->format_type; + } + else if (exprtype == JSONOID || exprtype == JSONBOID) + format = JS_FORMAT_DEFAULT; /* do not format json[b] types */ + else + format = default_format; + + if (format != JS_FORMAT_DEFAULT) + { + Oid targettype = format == JS_FORMAT_JSONB ? JSONBOID : JSONOID; + Node *orig = makeCaseTestExpr(expr); + Node *coerced; + + expr = orig; + + if (exprtype != BYTEAOID && typcategory != TYPCATEGORY_STRING) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg(ve->format->format_type == JS_FORMAT_DEFAULT ? + "cannot use non-string types with implicit FORMAT JSON clause" : + "cannot use non-string types with explicit FORMAT JSON clause"), + parser_errposition(pstate, ve->format->location >= 0 ? + ve->format->location : location))); + + /* Convert encoded JSON text from bytea. */ + if (format == JS_FORMAT_JSON && exprtype == BYTEAOID) + { + expr = makeJsonByteaToTextConversion(expr, ve->format, location); + exprtype = TEXTOID; + } + + /* Try to coerce to the target type. */ + coerced = coerce_to_target_type(pstate, expr, exprtype, + targettype, -1, + COERCION_EXPLICIT, + COERCE_EXPLICIT_CAST, + location); + + if (!coerced) + { + /* If coercion failed, use to_json()/to_jsonb() functions. */ + Oid fnoid = targettype == JSONOID ? F_TO_JSON : F_TO_JSONB; + FuncExpr *fexpr = makeFuncExpr(fnoid, targettype, + list_make1(expr), + InvalidOid, InvalidOid, + COERCE_EXPLICIT_CALL); + fexpr->location = location; + + coerced = (Node *) fexpr; + } + + if (coerced == orig) + expr = rawexpr; + else + { + ve = copyObject(ve); + ve->raw_expr = (Expr *) rawexpr; + ve->formatted_expr = (Expr *) coerced; + + expr = (Node *) ve; + } + } + + return expr; +} |