/*------------------------------------------------------------------------- * * parse_func.c * handle function calls in parser * * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * $Header: /cvsroot/pgsql/src/backend/parser/parse_func.c,v 1.162 2003/11/09 21:30:37 tgl Exp $ * *------------------------------------------------------------------------- */ #include "postgres.h" #include "access/heapam.h" #include "catalog/catname.h" #include "catalog/pg_inherits.h" #include "catalog/pg_proc.h" #include "lib/stringinfo.h" #include "nodes/makefuncs.h" #include "parser/parse_agg.h" #include "parser/parse_coerce.h" #include "parser/parse_expr.h" #include "parser/parse_func.h" #include "parser/parse_relation.h" #include "parser/parse_type.h" #include "utils/builtins.h" #include "utils/fmgroids.h" #include "utils/lsyscache.h" #include "utils/syscache.h" static Node *ParseComplexProjection(char *funcname, Node *first_arg); static Oid **argtype_inherit(int nargs, Oid *argtypes); static int find_inheritors(Oid relid, Oid **supervec); static Oid **gen_cross_product(InhPaths *arginh, int nargs); static FieldSelect *setup_field_select(Node *input, char *attname, Oid relid); static void unknown_attribute(const char *schemaname, const char *relname, const char *attname); /* * Parse a function call * * For historical reasons, Postgres tries to treat the notations tab.col * and col(tab) as equivalent: if a single-argument function call has an * argument of complex type and the (unqualified) function name matches * any attribute of the type, we take it as a column projection. * * Hence, both cases come through here. The is_column parameter tells us * which syntactic construct is actually being dealt with, but this is * intended to be used only to deliver an appropriate error message, * not to affect the semantics. When is_column is true, we should have * a single argument (the putative table), unqualified function name * equal to the column name, and no aggregate decoration. * * In the function-call case, the argument expressions have been transformed * already. In the column case, we may get either a transformed expression * or a RangeVar node as argument. */ Node * ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs, bool agg_star, bool agg_distinct, bool is_column) { Oid rettype; Oid funcid; List *i; Node *first_arg = NULL; int nargs = length(fargs); int argn; Oid actual_arg_types[FUNC_MAX_ARGS]; Oid *declared_arg_types; Node *retval; bool retset; FuncDetailCode fdresult; /* * Most of the rest of the parser just assumes that functions do not * have more than FUNC_MAX_ARGS parameters. We have to test here to * protect against array overruns, etc. Of course, this may not be a * function, but the test doesn't hurt. */ if (nargs > FUNC_MAX_ARGS) ereport(ERROR, (errcode(ERRCODE_TOO_MANY_ARGUMENTS), errmsg("cannot pass more than %d arguments to a function", FUNC_MAX_ARGS))); if (fargs) { first_arg = lfirst(fargs); Assert(first_arg != NULL); } /* * check for column projection: if function has one argument, and that * argument is of complex type, and function name is not qualified, * then the "function call" could be a projection. We also check that * there wasn't any aggregate decoration. */ if (nargs == 1 && !agg_star && !agg_distinct && length(funcname) == 1) { char *cname = strVal(lfirst(funcname)); /* Is it a not-yet-transformed RangeVar node? */ if (IsA(first_arg, RangeVar)) { /* First arg is a relation. This could be a projection. */ retval = qualifiedNameToVar(pstate, ((RangeVar *) first_arg)->schemaname, ((RangeVar *) first_arg)->relname, cname, true); if (retval) return retval; } else if (ISCOMPLEX(exprType(first_arg))) { /* * Attempt to handle projection of a complex argument. If * ParseComplexProjection can't handle the projection, we have * to keep going. */ retval = ParseComplexProjection(cname, first_arg); if (retval) return retval; } } /* * Okay, it's not a column projection, so it must really be a * function. Extract arg type info and transform RangeVar arguments * into varnodes of the appropriate form. */ MemSet(actual_arg_types, 0, FUNC_MAX_ARGS * sizeof(Oid)); argn = 0; foreach(i, fargs) { Node *arg = lfirst(i); Oid toid; if (IsA(arg, RangeVar)) { char *schemaname; char *relname; RangeTblEntry *rte; int vnum; int sublevels_up; /* * a relation: look it up in the range table, or add if needed */ schemaname = ((RangeVar *) arg)->schemaname; relname = ((RangeVar *) arg)->relname; rte = refnameRangeTblEntry(pstate, schemaname, relname, &sublevels_up); if (rte == NULL) rte = addImplicitRTE(pstate, (RangeVar *) arg); vnum = RTERangeTablePosn(pstate, rte, &sublevels_up); /* * The parameter to be passed to the function is the whole * tuple from the relation. We build a special VarNode to * reflect this -- it has varno set to the correct range table * entry, but has varattno == 0 to signal that the whole tuple * is the argument. Also, it has typmod set to * sizeof(Pointer) to signal that the runtime representation * will be a pointer not an Oid. */ switch (rte->rtekind) { case RTE_RELATION: toid = get_rel_type_id(rte->relid); if (!OidIsValid(toid)) elog(ERROR, "could not find type OID for relation %u", rte->relid); /* replace RangeVar in the arg list */ lfirst(i) = makeVar(vnum, InvalidAttrNumber, toid, sizeof(Pointer), sublevels_up); break; case RTE_FUNCTION: toid = exprType(rte->funcexpr); if (get_typtype(toid) == 'c') { /* func returns composite; same as relation case */ lfirst(i) = makeVar(vnum, InvalidAttrNumber, toid, sizeof(Pointer), sublevels_up); } else { /* func returns scalar; use attno 1 instead */ lfirst(i) = makeVar(vnum, 1, toid, -1, sublevels_up); } break; default: /* * RTE is a join or subselect; must fail for lack of a * named tuple type */ if (is_column) unknown_attribute(schemaname, relname, strVal(lfirst(funcname))); else ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot pass result of subquery or join \"%s\" to a function", relname))); toid = InvalidOid; /* keep compiler quiet */ break; } } else toid = exprType(arg); actual_arg_types[argn++] = toid; } /* * func_get_detail looks up the function in the catalogs, does * disambiguation for polymorphic functions, handles inheritance, and * returns the funcid and type and set or singleton status of the * function's return value. it also returns the true argument types * to the function. */ fdresult = func_get_detail(funcname, fargs, nargs, actual_arg_types, &funcid, &rettype, &retset, &declared_arg_types); if (fdresult == FUNCDETAIL_COERCION) { /* * We can do it as a trivial coercion. coerce_type can handle * these cases, so why duplicate code... */ return coerce_type(pstate, lfirst(fargs), actual_arg_types[0], rettype, COERCION_EXPLICIT, COERCE_EXPLICIT_CALL); } else if (fdresult == FUNCDETAIL_NORMAL) { /* * Normal function found; was there anything indicating it must be * an aggregate? */ if (agg_star) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("%s(*) specified, but %s is not an aggregate function", NameListToString(funcname), NameListToString(funcname)))); if (agg_distinct) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("DISTINCT specified, but %s is not an aggregate function", NameListToString(funcname)))); } else if (fdresult != FUNCDETAIL_AGGREGATE) { /* * Oops. Time to die. * * If we are dealing with the attribute notation rel.function, give * an error message that is appropriate for that case. */ if (is_column) { char *colname = strVal(lfirst(funcname)); Oid relTypeId; Assert(nargs == 1); if (IsA(first_arg, RangeVar)) unknown_attribute(((RangeVar *) first_arg)->schemaname, ((RangeVar *) first_arg)->relname, colname); relTypeId = exprType(first_arg); if (!ISCOMPLEX(relTypeId)) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("attribute notation .%s applied to type %s, which is not a complex type", colname, format_type_be(relTypeId)))); else ereport(ERROR, (errcode(ERRCODE_UNDEFINED_COLUMN), errmsg("attribute \"%s\" not found in data type %s", colname, format_type_be(relTypeId)))); } /* * Else generate a detailed complaint for a function */ if (fdresult == FUNCDETAIL_MULTIPLE) ereport(ERROR, (errcode(ERRCODE_AMBIGUOUS_FUNCTION), errmsg("function %s is not unique", func_signature_string(funcname, nargs, actual_arg_types)), errhint("Could not choose a best candidate function. " "You may need to add explicit type casts."))); else ereport(ERROR, (errcode(ERRCODE_UNDEFINED_FUNCTION), errmsg("function %s does not exist", func_signature_string(funcname, nargs, actual_arg_types)), errhint("No function matches the given name and argument types. " "You may need to add explicit type casts."))); } /* * enforce consistency with ANYARRAY and ANYELEMENT argument and * return types, possibly adjusting return type or declared_arg_types * (which will be used as the cast destination by make_fn_arguments) */ rettype = enforce_generic_type_consistency(actual_arg_types, declared_arg_types, nargs, rettype); /* perform the necessary typecasting of arguments */ make_fn_arguments(pstate, fargs, actual_arg_types, declared_arg_types); /* build the appropriate output structure */ if (fdresult == FUNCDETAIL_NORMAL) { FuncExpr *funcexpr = makeNode(FuncExpr); funcexpr->funcid = funcid; funcexpr->funcresulttype = rettype; funcexpr->funcretset = retset; funcexpr->funcformat = COERCE_EXPLICIT_CALL; funcexpr->args = fargs; retval = (Node *) funcexpr; } else { /* aggregate function */ Aggref *aggref = makeNode(Aggref); aggref->aggfnoid = funcid; aggref->aggtype = rettype; aggref->target = lfirst(fargs); aggref->aggstar = agg_star; aggref->aggdistinct = agg_distinct; /* parse_agg.c does additional aggregate-specific processing */ transformAggregateCall(pstate, aggref); retval = (Node *) aggref; if (retset) ereport(ERROR, (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION), errmsg("aggregates may not return sets"))); } return retval; } /* func_match_argtypes() * * Given a list of candidate functions (having the right name and number * of arguments) and an array of input datatype OIDs, produce a shortlist of * those candidates that actually accept the input datatypes (either exactly * or by coercion), and return the number of such candidates. * * Note that can_coerce_type will assume that UNKNOWN inputs are coercible to * anything, so candidates will not be eliminated on that basis. * * NB: okay to modify input list structure, as long as we find at least * one match. If no match at all, the list must remain unmodified. */ int func_match_argtypes(int nargs, Oid *input_typeids, FuncCandidateList raw_candidates, FuncCandidateList *candidates) /* return value */ { FuncCandidateList current_candidate; FuncCandidateList next_candidate; int ncandidates = 0; *candidates = NULL; for (current_candidate = raw_candidates; current_candidate != NULL; current_candidate = next_candidate) { next_candidate = current_candidate->next; if (can_coerce_type(nargs, input_typeids, current_candidate->args, COERCION_IMPLICIT)) { current_candidate->next = *candidates; *candidates = current_candidate; ncandidates++; } } return ncandidates; } /* func_match_argtypes() */ /* func_select_candidate() * Given the input argtype array and more than one candidate * for the function, attempt to resolve the conflict. * * Returns the selected candidate if the conflict can be resolved, * otherwise returns NULL. * * Note that the caller has already determined that there is no candidate * exactly matching the input argtypes, and has pruned away any "candidates" * that aren't actually coercion-compatible with the input types. * * This is also used for resolving ambiguous operator references. Formerly * parse_oper.c had its own, essentially duplicate code for the purpose. * The following comments (formerly in parse_oper.c) are kept to record some * of the history of these heuristics. * * OLD COMMENTS: * * This routine is new code, replacing binary_oper_select_candidate() * which dates from v4.2/v1.0.x days. It tries very hard to match up * operators with types, including allowing type coercions if necessary. * The important thing is that the code do as much as possible, * while _never_ doing the wrong thing, where "the wrong thing" would * be returning an operator when other better choices are available, * or returning an operator which is a non-intuitive possibility. * - thomas 1998-05-21 * * The comments below came from binary_oper_select_candidate(), and * illustrate the issues and choices which are possible: * - thomas 1998-05-20 * * current wisdom holds that the default operator should be one in which * both operands have the same type (there will only be one such * operator) * * 7.27.93 - I have decided not to do this; it's too hard to justify, and * it's easy enough to typecast explicitly - avi * [the rest of this routine was commented out since then - ay] * * 6/23/95 - I don't complete agree with avi. In particular, casting * floats is a pain for users. Whatever the rationale behind not doing * this is, I need the following special case to work. * * In the WHERE clause of a query, if a float is specified without * quotes, we treat it as float8. I added the float48* operators so * that we can operate on float4 and float8. But now we have more than * one matching operator if the right arg is unknown (eg. float * specified with quotes). This break some stuff in the regression * test where there are floats in quotes not properly casted. Below is * the solution. In addition to requiring the operator operates on the * same type for both operands [as in the code Avi originally * commented out], we also require that the operators be equivalent in * some sense. (see equivalentOpersAfterPromotion for details.) * - ay 6/95 */ FuncCandidateList func_select_candidate(int nargs, Oid *input_typeids, FuncCandidateList candidates) { FuncCandidateList current_candidate; FuncCandidateList last_candidate; Oid *current_typeids; Oid current_type; int i; int ncandidates; int nbestMatch, nmatch; Oid input_base_typeids[FUNC_MAX_ARGS]; CATEGORY slot_category[FUNC_MAX_ARGS], current_category; bool slot_has_preferred_type[FUNC_MAX_ARGS]; bool resolved_unknowns; /* * If any input types are domains, reduce them to their base types. * This ensures that we will consider functions on the base type to be * "exact matches" in the exact-match heuristic; it also makes it * possible to do something useful with the type-category heuristics. * Note that this makes it difficult, but not impossible, to use * functions declared to take a domain as an input datatype. Such a * function will be selected over the base-type function only if it is * an exact match at all argument positions, and so was already chosen * by our caller. */ for (i = 0; i < nargs; i++) input_base_typeids[i] = getBaseType(input_typeids[i]); /* * Run through all candidates and keep those with the most matches on * exact types. Keep all candidates if none match. */ ncandidates = 0; nbestMatch = 0; last_candidate = NULL; for (current_candidate = candidates; current_candidate != NULL; current_candidate = current_candidate->next) { current_typeids = current_candidate->args; nmatch = 0; for (i = 0; i < nargs; i++) { if (input_base_typeids[i] != UNKNOWNOID && current_typeids[i] == input_base_typeids[i]) nmatch++; } /* take this one as the best choice so far? */ if ((nmatch > nbestMatch) || (last_candidate == NULL)) { nbestMatch = nmatch; candidates = current_candidate; last_candidate = current_candidate; ncandidates = 1; } /* no worse than the last choice, so keep this one too? */ else if (nmatch == nbestMatch) { last_candidate->next = current_candidate; last_candidate = current_candidate; ncandidates++; } /* otherwise, don't bother keeping this one... */ } if (last_candidate) /* terminate rebuilt list */ last_candidate->next = NULL; if (ncandidates == 1) return candidates; /* * Still too many candidates? Now look for candidates which have * either exact matches or preferred types at the args that will * require coercion. (Restriction added in 7.4: preferred type must be * of same category as input type; give no preference to * cross-category conversions to preferred types.) Keep all * candidates if none match. */ for (i = 0; i < nargs; i++) /* avoid multiple lookups */ slot_category[i] = TypeCategory(input_base_typeids[i]); ncandidates = 0; nbestMatch = 0; last_candidate = NULL; for (current_candidate = candidates; current_candidate != NULL; current_candidate = current_candidate->next) { current_typeids = current_candidate->args; nmatch = 0; for (i = 0; i < nargs; i++) { if (input_base_typeids[i] != UNKNOWNOID) { if (current_typeids[i] == input_base_typeids[i] || IsPreferredType(slot_category[i], current_typeids[i])) nmatch++; } } if ((nmatch > nbestMatch) || (last_candidate == NULL)) { nbestMatch = nmatch; candidates = current_candidate; last_candidate = current_candidate; ncandidates = 1; } else if (nmatch == nbestMatch) { last_candidate->next = current_candidate; last_candidate = current_candidate; ncandidates++; } } if (last_candidate) /* terminate rebuilt list */ last_candidate->next = NULL; if (ncandidates == 1) return candidates; /* * Still too many candidates? Try assigning types for the unknown * columns. * * NOTE: for a binary operator with one unknown and one non-unknown * input, we already tried the heuristic of looking for a candidate * with the known input type on both sides (see binary_oper_exact()). * That's essentially a special case of the general algorithm we try * next. * * We do this by examining each unknown argument position to see if we * can determine a "type category" for it. If any candidate has an * input datatype of STRING category, use STRING category (this bias * towards STRING is appropriate since unknown-type literals look like * strings). Otherwise, if all the candidates agree on the type * category of this argument position, use that category. Otherwise, * fail because we cannot determine a category. * * If we are able to determine a type category, also notice whether any * of the candidates takes a preferred datatype within the category. * * Having completed this examination, remove candidates that accept the * wrong category at any unknown position. Also, if at least one * candidate accepted a preferred type at a position, remove * candidates that accept non-preferred types. * * If we are down to one candidate at the end, we win. */ resolved_unknowns = false; for (i = 0; i < nargs; i++) { bool have_conflict; if (input_base_typeids[i] != UNKNOWNOID) continue; resolved_unknowns = true; /* assume we can do it */ slot_category[i] = INVALID_TYPE; slot_has_preferred_type[i] = false; have_conflict = false; for (current_candidate = candidates; current_candidate != NULL; current_candidate = current_candidate->next) { current_typeids = current_candidate->args; current_type = current_typeids[i]; current_category = TypeCategory(current_type); if (slot_category[i] == INVALID_TYPE) { /* first candidate */ slot_category[i] = current_category; slot_has_preferred_type[i] = IsPreferredType(current_category, current_type); } else if (current_category == slot_category[i]) { /* more candidates in same category */ slot_has_preferred_type[i] |= IsPreferredType(current_category, current_type); } else { /* category conflict! */ if (current_category == STRING_TYPE) { /* STRING always wins if available */ slot_category[i] = current_category; slot_has_preferred_type[i] = IsPreferredType(current_category, current_type); } else { /* * Remember conflict, but keep going (might find * STRING) */ have_conflict = true; } } } if (have_conflict && slot_category[i] != STRING_TYPE) { /* Failed to resolve category conflict at this position */ resolved_unknowns = false; break; } } if (resolved_unknowns) { /* Strip non-matching candidates */ ncandidates = 0; last_candidate = NULL; for (current_candidate = candidates; current_candidate != NULL; current_candidate = current_candidate->next) { bool keepit = true; current_typeids = current_candidate->args; for (i = 0; i < nargs; i++) { if (input_base_typeids[i] != UNKNOWNOID) continue; current_type = current_typeids[i]; current_category = TypeCategory(current_type); if (current_category != slot_category[i]) { keepit = false; break; } if (slot_has_preferred_type[i] && !IsPreferredType(current_category, current_type)) { keepit = false; break; } } if (keepit) { /* keep this candidate */ last_candidate = current_candidate; ncandidates++; } else { /* forget this candidate */ if (last_candidate) last_candidate->next = current_candidate->next; else candidates = current_candidate->next; } } if (last_candidate) /* terminate rebuilt list */ last_candidate->next = NULL; } if (ncandidates == 1) return candidates; return NULL; /* failed to select a best candidate */ } /* func_select_candidate() */ /* func_get_detail() * * Find the named function in the system catalogs. * * Attempt to find the named function in the system catalogs with * arguments exactly as specified, so that the normal case * (exact match) is as quick as possible. * * If an exact match isn't found: * 1) check for possible interpretation as a trivial type coercion * 2) get a vector of all possible input arg type arrays constructed * from the superclasses of the original input arg types * 3) get a list of all possible argument type arrays to the function * with given name and number of arguments * 4) for each input arg type array from vector #1: * a) find how many of the function arg type arrays from list #2 * it can be coerced to * b) if the answer is one, we have our function * c) if the answer is more than one, attempt to resolve the conflict * d) if the answer is zero, try the next array from vector #1 * * Note: we rely primarily on nargs/argtypes as the argument description. * The actual expression node list is passed in fargs so that we can check * for type coercion of a constant. Some callers pass fargs == NIL * indicating they don't want that check made. */ FuncDetailCode func_get_detail(List *funcname, List *fargs, int nargs, Oid *argtypes, Oid *funcid, /* return value */ Oid *rettype, /* return value */ bool *retset, /* return value */ Oid **true_typeids) /* return value */ { FuncCandidateList raw_candidates; FuncCandidateList best_candidate; /* Get list of possible candidates from namespace search */ raw_candidates = FuncnameGetCandidates(funcname, nargs); /* * Quickly check if there is an exact match to the input datatypes * (there can be only one) */ for (best_candidate = raw_candidates; best_candidate != NULL; best_candidate = best_candidate->next) { if (memcmp(argtypes, best_candidate->args, nargs * sizeof(Oid)) == 0) break; } if (best_candidate == NULL) { /* * If we didn't find an exact match, next consider the possibility * that this is really a type-coercion request: a single-argument * function call where the function name is a type name. If so, * and if we can do the coercion trivially (no run-time function * call needed), then go ahead and treat the "function call" as a * coercion. This interpretation needs to be given higher * priority than interpretations involving a type coercion * followed by a function call, otherwise we can produce * surprising results. For example, we want "text(varchar)" to be * interpreted as a trivial coercion, not as "text(name(varchar))" * which the code below this point is entirely capable of * selecting. * * "Trivial" coercions are ones that involve binary-compatible types * and ones that are coercing a previously-unknown-type literal * constant to a specific type. * * The reason we can restrict our check to binary-compatible * coercions here is that we expect non-binary-compatible * coercions to have an implementation function named after the * target type. That function will be found by normal lookup if * appropriate. * * NB: it's important that this code stays in sync with what * coerce_type can do, because the caller will try to apply * coerce_type if we return FUNCDETAIL_COERCION. If we return * that result for something coerce_type can't handle, we'll cause * infinite recursion between this module and coerce_type! */ if (nargs == 1 && fargs != NIL) { Oid targetType; TypeName *tn = makeNode(TypeName); tn->names = funcname; tn->typmod = -1; targetType = LookupTypeName(tn); if (OidIsValid(targetType) && !ISCOMPLEX(targetType)) { Oid sourceType = argtypes[0]; Node *arg1 = lfirst(fargs); if ((sourceType == UNKNOWNOID && IsA(arg1, Const)) || (find_coercion_pathway(targetType, sourceType, COERCION_EXPLICIT, funcid) && *funcid == InvalidOid)) { /* Yup, it's a type coercion */ *funcid = InvalidOid; *rettype = targetType; *retset = false; *true_typeids = argtypes; return FUNCDETAIL_COERCION; } } } /* * didn't find an exact match, so now try to match up * candidates... */ if (raw_candidates != NULL) { Oid **input_typeid_vector = NULL; Oid *current_input_typeids; /* * First we will search with the given argtypes, then with * variants based on replacing complex types with their * inheritance ancestors. Stop as soon as any match is found. */ current_input_typeids = argtypes; do { FuncCandidateList current_candidates; int ncandidates; ncandidates = func_match_argtypes(nargs, current_input_typeids, raw_candidates, ¤t_candidates); /* one match only? then run with it... */ if (ncandidates == 1) { best_candidate = current_candidates; break; } /* * multiple candidates? then better decide or throw an * error... */ if (ncandidates > 1) { best_candidate = func_select_candidate(nargs, current_input_typeids, current_candidates); /* * If we were able to choose a best candidate, we're * done. Otherwise, ambiguous function call. */ if (best_candidate) break; return FUNCDETAIL_MULTIPLE; } /* * No match here, so try the next inherited type vector. * First time through, we need to compute the list of * vectors. */ if (input_typeid_vector == NULL) input_typeid_vector = argtype_inherit(nargs, argtypes); current_input_typeids = *input_typeid_vector++; } while (current_input_typeids != NULL); } } if (best_candidate) { HeapTuple ftup; Form_pg_proc pform; FuncDetailCode result; *funcid = best_candidate->oid; *true_typeids = best_candidate->args; ftup = SearchSysCache(PROCOID, ObjectIdGetDatum(best_candidate->oid), 0, 0, 0); if (!HeapTupleIsValid(ftup)) /* should not happen */ elog(ERROR, "cache lookup failed for function %u", best_candidate->oid); pform = (Form_pg_proc) GETSTRUCT(ftup); *rettype = pform->prorettype; *retset = pform->proretset; result = pform->proisagg ? FUNCDETAIL_AGGREGATE : FUNCDETAIL_NORMAL; ReleaseSysCache(ftup); return result; } return FUNCDETAIL_NOTFOUND; } /* * argtype_inherit() -- Construct an argtype vector reflecting the * inheritance properties of the supplied argv. * * This function is used to handle resolution of function calls when * there is no match to the given argument types, but there might be * matches based on considering complex types as members of their * superclass types (parent classes). * * It takes an array of input type ids. For each type id in the array * that's a complex type (a class), it walks up the inheritance tree, * finding all superclasses of that type. A vector of new Oid type * arrays is returned to the caller, listing possible alternative * interpretations of the input typeids as members of their superclasses * rather than the actually given argument types. The vector is * terminated by a NULL pointer. * * The order of this vector is as follows: all superclasses of the * rightmost complex class are explored first. The exploration * continues from right to left. This policy means that we favor * keeping the leftmost argument type as low in the inheritance tree * as possible. This is intentional; it is exactly what we need to * do for method dispatch. * * The vector does not include the case where no complex classes have * been promoted, since that was already tried before this routine * got called. */ static Oid ** argtype_inherit(int nargs, Oid *argtypes) { Oid relid; int i; InhPaths arginh[FUNC_MAX_ARGS]; for (i = 0; i < nargs; i++) { arginh[i].self = argtypes[i]; if ((relid = typeidTypeRelid(argtypes[i])) != InvalidOid) arginh[i].nsupers = find_inheritors(relid, &(arginh[i].supervec)); else { arginh[i].nsupers = 0; arginh[i].supervec = (Oid *) NULL; } } /* return an ordered cross-product of the classes involved */ return gen_cross_product(arginh, nargs); } /* * Look up the parent superclass(es) of the given relation. * * *supervec is set to an array of the type OIDs (not the relation OIDs) * of the parents, with nearest ancestors listed first. It's set to NULL * if there are no parents. The return value is the number of parents. */ static int find_inheritors(Oid relid, Oid **supervec) { Relation inhrel; HeapScanDesc inhscan; ScanKeyData skey; HeapTuple inhtup; Oid *relidvec; int nvisited; List *visited, *queue; List *elt; bool newrelid; nvisited = 0; queue = NIL; visited = NIL; inhrel = heap_openr(InheritsRelationName, AccessShareLock); /* * Use queue to do a breadth-first traversal of the inheritance graph * from the relid supplied up to the root. At the top of the loop, * relid is the OID of the reltype to check next, queue is the list of * pending relids to check after this one, and visited is the list of * relids we need to output. */ do { /* find all types this relid inherits from, and add them to queue */ ScanKeyEntryInitialize(&skey, 0, Anum_pg_inherits_inhrelid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(relid), OIDOID); inhscan = heap_beginscan(inhrel, SnapshotNow, 1, &skey); while ((inhtup = heap_getnext(inhscan, ForwardScanDirection)) != NULL) { Form_pg_inherits inh = (Form_pg_inherits) GETSTRUCT(inhtup); queue = lappendo(queue, inh->inhparent); } heap_endscan(inhscan); /* pull next unvisited relid off the queue */ newrelid = false; while (queue != NIL) { relid = lfirsto(queue); queue = lnext(queue); if (!oidMember(relid, visited)) { newrelid = true; break; } } if (newrelid) { visited = lappendo(visited, relid); nvisited++; } } while (newrelid); heap_close(inhrel, AccessShareLock); if (nvisited > 0) { relidvec = (Oid *) palloc(nvisited * sizeof(Oid)); *supervec = relidvec; foreach(elt, visited) { /* return the type id, rather than the relation id */ *relidvec++ = get_rel_type_id(lfirsto(elt)); } } else *supervec = (Oid *) NULL; freeList(visited); /* * there doesn't seem to be any equally easy way to release the queue * list cells, but since they're palloc'd space it's not critical. */ return nvisited; } /* * Generate the ordered list of substitute argtype vectors to try. * * See comments for argtype_inherit. */ static Oid ** gen_cross_product(InhPaths *arginh, int nargs) { int nanswers; Oid **result; Oid *oneres; int i, j; int cur[FUNC_MAX_ARGS]; /* * At each position we want to try the original datatype, plus each * supertype. So the number of possible combinations is this: */ nanswers = 1; for (i = 0; i < nargs; i++) nanswers *= (arginh[i].nsupers + 1); /* * We also need an extra slot for the terminating NULL in the result * array, but that cancels out with the fact that we don't want to * generate the zero-changes case. So we need exactly nanswers slots. */ result = (Oid **) palloc(sizeof(Oid *) * nanswers); j = 0; /* * Compute the cross product from right to left. When cur[i] == 0, * generate the original input type at position i. When cur[i] == k * for k > 0, generate its k'th supertype. */ MemSet(cur, 0, sizeof(cur)); for (;;) { /* * Find a column we can increment. All the columns after it get * reset to zero. (Essentially, we're adding one to the multi- * digit number represented by cur[].) */ for (i = nargs - 1; i >= 0 && cur[i] >= arginh[i].nsupers; i--) cur[i] = 0; /* if none, we're done */ if (i < 0) break; /* increment this column */ cur[i] += 1; /* Generate the proper output type-OID vector */ oneres = (Oid *) palloc0(FUNC_MAX_ARGS * sizeof(Oid)); for (i = 0; i < nargs; i++) { if (cur[i] == 0) oneres[i] = arginh[i].self; else oneres[i] = arginh[i].supervec[cur[i] - 1]; } result[j++] = oneres; } /* terminate result vector with NULL pointer */ result[j++] = NULL; Assert(j == nanswers); return result; } /* * Given two type OIDs, determine whether the first is a complex type * (class type) that inherits from the second. */ bool typeInheritsFrom(Oid subclassTypeId, Oid superclassTypeId) { Oid relid; Oid *supervec; int nsupers, i; bool result; if (!ISCOMPLEX(subclassTypeId) || !ISCOMPLEX(superclassTypeId)) return false; relid = typeidTypeRelid(subclassTypeId); if (relid == InvalidOid) return false; nsupers = find_inheritors(relid, &supervec); result = false; for (i = 0; i < nsupers; i++) { if (supervec[i] == superclassTypeId) { result = true; break; } } if (supervec) pfree(supervec); return result; } /* * make_fn_arguments() * * Given the actual argument expressions for a function, and the desired * input types for the function, add any necessary typecasting to the * expression tree. Caller should already have verified that casting is * allowed. * * Caution: given argument list is modified in-place. * * As with coerce_type, pstate may be NULL if no special unknown-Param * processing is wanted. */ void make_fn_arguments(ParseState *pstate, List *fargs, Oid *actual_arg_types, Oid *declared_arg_types) { List *current_fargs; int i = 0; foreach(current_fargs, fargs) { /* types don't match? then force coercion using a function call... */ if (actual_arg_types[i] != declared_arg_types[i]) { lfirst(current_fargs) = coerce_type(pstate, lfirst(current_fargs), actual_arg_types[i], declared_arg_types[i], COERCION_IMPLICIT, COERCE_IMPLICIT_CAST); } i++; } } /* * setup_field_select * Build a FieldSelect node that says which attribute to project to. * This routine is called by ParseFuncOrColumn() when we have found * a projection on a function result or parameter. */ static FieldSelect * setup_field_select(Node *input, char *attname, Oid relid) { FieldSelect *fselect = makeNode(FieldSelect); AttrNumber attno; attno = get_attnum(relid, attname); if (attno == InvalidAttrNumber) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_COLUMN), errmsg("column \"%s\" of relation \"%s\" does not exist", attname, get_rel_name(relid)))); fselect->arg = (Expr *) input; fselect->fieldnum = attno; fselect->resulttype = get_atttype(relid, attno); fselect->resulttypmod = get_atttypmod(relid, attno); return fselect; } /* * ParseComplexProjection - * handles function calls with a single argument that is of complex type. * If the function call is actually a column projection, return a suitably * transformed expression tree. If not, return NULL. * * NB: argument is expected to be transformed already, ie, not a RangeVar. */ static Node * ParseComplexProjection(char *funcname, Node *first_arg) { Oid argtype = exprType(first_arg); Oid argrelid; AttrNumber attnum; FieldSelect *fselect; argrelid = typeidTypeRelid(argtype); if (!argrelid) return NULL; /* probably should not happen */ attnum = get_attnum(argrelid, funcname); if (attnum == InvalidAttrNumber) return NULL; /* funcname does not match any column */ /* * Check for special cases where we don't want to return a * FieldSelect. */ switch (nodeTag(first_arg)) { case T_Var: { Var *var = (Var *) first_arg; /* * If the Var is a whole-row tuple, we can just replace it * with a simple Var reference. */ if (var->varattno == InvalidAttrNumber) { Oid vartype; int32 vartypmod; get_atttypetypmod(argrelid, attnum, &vartype, &vartypmod); return (Node *) makeVar(var->varno, attnum, vartype, vartypmod, var->varlevelsup); } break; } default: break; } /* Else generate a FieldSelect expression */ fselect = setup_field_select(first_arg, funcname, argrelid); return (Node *) fselect; } /* * Simple helper routine for delivering "column does not exist" error message */ static void unknown_attribute(const char *schemaname, const char *relname, const char *attname) { if (schemaname) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_COLUMN), errmsg("column %s.%s.%s does not exist", schemaname, relname, attname))); else ereport(ERROR, (errcode(ERRCODE_UNDEFINED_COLUMN), errmsg("column %s.%s does not exist", relname, attname))); } /* * funcname_signature_string * Build a string representing a function name, including arg types. * The result is something like "foo(integer)". * * This is typically used in the construction of function-not-found error * messages. */ const char * funcname_signature_string(const char *funcname, int nargs, const Oid *argtypes) { StringInfoData argbuf; int i; initStringInfo(&argbuf); appendStringInfo(&argbuf, "%s(", funcname); for (i = 0; i < nargs; i++) { if (i) appendStringInfoString(&argbuf, ", "); appendStringInfoString(&argbuf, format_type_be(argtypes[i])); } appendStringInfoChar(&argbuf, ')'); return argbuf.data; /* return palloc'd string buffer */ } /* * func_signature_string * As above, but function name is passed as a qualified name list. */ const char * func_signature_string(List *funcname, int nargs, const Oid *argtypes) { return funcname_signature_string(NameListToString(funcname), nargs, argtypes); } /* * find_aggregate_func * Convenience routine to check that a function exists and is an * aggregate. * * Note: basetype is ANYOID if we are looking for an aggregate on * all types. */ Oid find_aggregate_func(List *aggname, Oid basetype, bool noError) { Oid oid; HeapTuple ftup; Form_pg_proc pform; oid = LookupFuncName(aggname, 1, &basetype, true); if (!OidIsValid(oid)) { if (noError) return InvalidOid; if (basetype == ANYOID) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_FUNCTION), errmsg("aggregate %s(*) does not exist", NameListToString(aggname)))); else ereport(ERROR, (errcode(ERRCODE_UNDEFINED_FUNCTION), errmsg("aggregate %s(%s) does not exist", NameListToString(aggname), format_type_be(basetype)))); } /* Make sure it's an aggregate */ ftup = SearchSysCache(PROCOID, ObjectIdGetDatum(oid), 0, 0, 0); if (!HeapTupleIsValid(ftup)) /* should not happen */ elog(ERROR, "cache lookup failed for function %u", oid); pform = (Form_pg_proc) GETSTRUCT(ftup); if (!pform->proisagg) { ReleaseSysCache(ftup); if (noError) return InvalidOid; /* we do not use the (*) notation for functions... */ ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("function %s(%s) is not an aggregate", NameListToString(aggname), format_type_be(basetype)))); } ReleaseSysCache(ftup); return oid; } /* * LookupFuncName * Given a possibly-qualified function name and a set of argument types, * look up the function. * * If the function name is not schema-qualified, it is sought in the current * namespace search path. * * If the function is not found, we return InvalidOid if noError is true, * else raise an error. */ Oid LookupFuncName(List *funcname, int nargs, const Oid *argtypes, bool noError) { FuncCandidateList clist; clist = FuncnameGetCandidates(funcname, nargs); while (clist) { if (memcmp(argtypes, clist->args, nargs * sizeof(Oid)) == 0) return clist->oid; clist = clist->next; } if (!noError) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_FUNCTION), errmsg("function %s does not exist", func_signature_string(funcname, nargs, argtypes)))); return InvalidOid; } /* * LookupFuncNameTypeNames * Like LookupFuncName, but the argument types are specified by a * list of TypeName nodes. */ Oid LookupFuncNameTypeNames(List *funcname, List *argtypes, bool noError) { Oid argoids[FUNC_MAX_ARGS]; int argcount; int i; MemSet(argoids, 0, FUNC_MAX_ARGS * sizeof(Oid)); argcount = length(argtypes); if (argcount > FUNC_MAX_ARGS) ereport(ERROR, (errcode(ERRCODE_TOO_MANY_ARGUMENTS), errmsg("functions cannot have more than %d arguments", FUNC_MAX_ARGS))); for (i = 0; i < argcount; i++) { TypeName *t = (TypeName *) lfirst(argtypes); argoids[i] = LookupTypeName(t); if (!OidIsValid(argoids[i])) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("type \"%s\" does not exist", TypeNameToString(t)))); argtypes = lnext(argtypes); } return LookupFuncName(funcname, argcount, argoids, noError); }