diff options
Diffstat (limited to 'src/backend/parser/parse_oper.c')
| -rw-r--r-- | src/backend/parser/parse_oper.c | 149 |
1 files changed, 101 insertions, 48 deletions
diff --git a/src/backend/parser/parse_oper.c b/src/backend/parser/parse_oper.c index e55f638765b..cd557994f17 100644 --- a/src/backend/parser/parse_oper.c +++ b/src/backend/parser/parse_oper.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/parser/parse_oper.c,v 1.46 2001/01/24 19:43:02 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/parser/parse_oper.c,v 1.47 2001/02/16 03:16:58 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -40,15 +40,15 @@ static void unary_op_error(char *op, Oid arg, bool is_left_op); /* Select an ordering operator for the given datatype */ Oid -any_ordering_op(Oid restype) +any_ordering_op(Oid argtype) { Oid order_opid; - order_opid = oper_oid("<", restype, restype, true); + order_opid = compatible_oper_opid("<", argtype, argtype, true); if (!OidIsValid(order_opid)) elog(ERROR, "Unable to identify an ordering operator '%s' for type '%s'" "\n\tUse an explicit ordering operator or modify the query", - "<", typeidTypeName(restype)); + "<", typeidTypeName(argtype)); return order_opid; } @@ -59,6 +59,15 @@ oprid(Operator op) return op->t_data->t_oid; } +/* given operator tuple, return the underlying function's OID */ +Oid +oprfuncid(Operator op) +{ + Form_pg_operator pgopform = (Form_pg_operator) GETSTRUCT(op); + + return pgopform->oprcode; +} + /* binary_oper_get_candidates() * given opname, find all possible input type pairs for which an operator @@ -119,7 +128,7 @@ binary_oper_get_candidates(char *opname, /* oper_select_candidate() - * Given the input argtype array and more than one candidate + * Given the input argtype array and one or more candidates * for the function argtype array, attempt to resolve the conflict. * Returns the selected argtype array if the conflict can be resolved, * otherwise returns NULL. @@ -593,34 +602,22 @@ oper_inexact(char *op, Oid arg1, Oid arg2) if (ncandidates == 0) return NULL; - /* Or found exactly one? Then proceed... */ - else if (ncandidates == 1) + /* Otherwise, check for compatible datatypes, and then try to resolve + * the conflict if more than one candidate remains. + */ + inputOids[0] = arg1; + inputOids[1] = arg2; + targetOids = oper_select_candidate(2, inputOids, candidates); + if (targetOids != NULL) { tup = SearchSysCache(OPERNAME, PointerGetDatum(op), - ObjectIdGetDatum(candidates->args[0]), - ObjectIdGetDatum(candidates->args[1]), + ObjectIdGetDatum(targetOids[0]), + ObjectIdGetDatum(targetOids[1]), CharGetDatum('b')); - Assert(HeapTupleIsValid(tup)); } - - /* Otherwise, multiple operators of the desired types found... */ else - { - inputOids[0] = arg1; - inputOids[1] = arg2; - targetOids = oper_select_candidate(2, inputOids, candidates); - if (targetOids != NULL) - { - tup = SearchSysCache(OPERNAME, - PointerGetDatum(op), - ObjectIdGetDatum(targetOids[0]), - ObjectIdGetDatum(targetOids[1]), - CharGetDatum('b')); - } - else - tup = NULL; - } + tup = NULL; return (Operator) tup; } @@ -628,6 +625,10 @@ oper_inexact(char *op, Oid arg1, Oid arg2) /* oper() -- search for a binary operator * Given operator name, types of arg1 and arg2, return oper struct. * + * IMPORTANT: the returned operator (if any) is only promised to be + * coercion-compatible with the input datatypes. Do not use this if + * you need an exact- or binary-compatible match; see compatible_oper. + * * If no matching operator found, return NULL if noError is true, * raise an error if it is false. * @@ -653,19 +654,51 @@ oper(char *opname, Oid ltypeId, Oid rtypeId, bool noError) return (Operator) NULL; } -/* oper_oid() -- get OID of a binary operator +/* compatible_oper() + * given an opname and input datatypes, find a compatible binary operator + * + * This is tighter than oper() because it will not return an operator that + * requires coercion of the input datatypes (but binary-compatible operators + * are accepted). Otherwise, the semantics are the same. + */ +Operator +compatible_oper(char *op, Oid arg1, Oid arg2, bool noError) +{ + Operator optup; + Form_pg_operator opform; + + /* oper() will find the best available match */ + optup = oper(op, arg1, arg2, noError); + if (optup == (Operator) NULL) + return (Operator) NULL; /* must be noError case */ + + /* but is it good enough? */ + opform = (Form_pg_operator) GETSTRUCT(optup); + if ((opform->oprleft == arg1 || + IS_BINARY_COMPATIBLE(opform->oprleft, arg1)) && + (opform->oprright == arg2 || + IS_BINARY_COMPATIBLE(opform->oprright, arg2))) + return optup; + + if (!noError) + op_error(op, arg1, arg2); + + return (Operator) NULL; +} + +/* compatible_oper_opid() -- get OID of a binary operator * * This is a convenience routine that extracts only the operator OID - * from the result of oper(). InvalidOid is returned if the lookup - * fails and noError is true. + * from the result of compatible_oper(). InvalidOid is returned if the + * lookup fails and noError is true. */ Oid -oper_oid(char *op, Oid arg1, Oid arg2, bool noError) +compatible_oper_opid(char *op, Oid arg1, Oid arg2, bool noError) { Operator optup; Oid result; - optup = oper(op, arg1, arg2, noError); + optup = compatible_oper(op, arg1, arg2, noError); if (optup != NULL) { result = oprid(optup); @@ -675,6 +708,28 @@ oper_oid(char *op, Oid arg1, Oid arg2, bool noError) return InvalidOid; } +/* compatible_oper_funcid() -- get OID of a binary operator's function + * + * This is a convenience routine that extracts only the function OID + * from the result of compatible_oper(). InvalidOid is returned if the + * lookup fails and noError is true. + */ +Oid +compatible_oper_funcid(char *op, Oid arg1, Oid arg2, bool noError) +{ + Operator optup; + Oid result; + + optup = compatible_oper(op, arg1, arg2, noError); + if (optup != NULL) + { + result = oprfuncid(optup); + ReleaseSysCache(optup); + return result; + } + return InvalidOid; +} + /* unary_oper_get_candidates() * given opname, find all possible types for which * a right/left unary operator named opname exists. @@ -738,6 +793,10 @@ unary_oper_get_candidates(char *opname, /* Given unary right operator (operator on right), return oper struct * + * IMPORTANT: the returned operator (if any) is only promised to be + * coercion-compatible with the input datatype. Do not use this if + * you need an exact- or binary-compatible match. + * * Always raises error on failure. * * NOTE: on success, the returned object is a syscache entry. The caller @@ -764,16 +823,11 @@ right_oper(char *op, Oid arg) ncandidates = unary_oper_get_candidates(op, &candidates, 'r'); if (ncandidates == 0) unary_op_error(op, arg, FALSE); - else if (ncandidates == 1) - { - tup = SearchSysCache(OPERNAME, - PointerGetDatum(op), - ObjectIdGetDatum(candidates->args[0]), - ObjectIdGetDatum(InvalidOid), - CharGetDatum('r')); - } else { + /* We must run oper_select_candidate even if only one candidate, + * otherwise we may falsely return a non-type-compatible operator. + */ targetOid = oper_select_candidate(1, &arg, candidates); if (targetOid != NULL) tup = SearchSysCache(OPERNAME, @@ -793,6 +847,10 @@ right_oper(char *op, Oid arg) /* Given unary left operator (operator on left), return oper struct * + * IMPORTANT: the returned operator (if any) is only promised to be + * coercion-compatible with the input datatype. Do not use this if + * you need an exact- or binary-compatible match. + * * Always raises error on failure. * * NOTE: on success, the returned object is a syscache entry. The caller @@ -819,16 +877,11 @@ left_oper(char *op, Oid arg) ncandidates = unary_oper_get_candidates(op, &candidates, 'l'); if (ncandidates == 0) unary_op_error(op, arg, TRUE); - else if (ncandidates == 1) - { - tup = SearchSysCache(OPERNAME, - PointerGetDatum(op), - ObjectIdGetDatum(InvalidOid), - ObjectIdGetDatum(candidates->args[0]), - CharGetDatum('l')); - } else { + /* We must run oper_select_candidate even if only one candidate, + * otherwise we may falsely return a non-type-compatible operator. + */ targetOid = oper_select_candidate(1, &arg, candidates); if (targetOid != NULL) tup = SearchSysCache(OPERNAME, |