/*------------------------------------------------------------------------- * * parse_func.c * handle function calls in parser * * Portions Copyright (c) 1996-2000, PostgreSQL, Inc * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * $Header: /cvsroot/pgsql/src/backend/parser/parse_func.c,v 1.86 2000/08/03 19:19:34 tgl Exp $ * *------------------------------------------------------------------------- */ #include "postgres.h" #include "access/genam.h" #include "access/heapam.h" #include "catalog/catname.h" #include "catalog/indexing.h" #include "catalog/pg_aggregate.h" #include "catalog/pg_inherits.h" #include "catalog/pg_proc.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/fmgroids.h" #include "utils/lsyscache.h" #include "utils/syscache.h" static Node *ParseComplexProjection(ParseState *pstate, char *funcname, Node *first_arg, bool *attisset); static Oid **argtype_inherit(int nargs, Oid *oid_array); static int find_inheritors(Oid relid, Oid **supervec); static CandidateList func_get_candidates(char *funcname, int nargs); static bool func_get_detail(char *funcname, int nargs, Oid *oid_array, Oid *funcid, /* return value */ Oid *rettype, /* return value */ bool *retset, /* return value */ Oid **true_typeids); static Oid **gen_cross_product(InhPaths *arginh, int nargs); static void make_arguments(ParseState *pstate, int nargs, List *fargs, Oid *input_typeids, Oid *function_typeids); static int match_argtypes(int nargs, Oid *input_typeids, CandidateList function_typeids, CandidateList *candidates); static List *setup_tlist(char *attname, Oid relid); static Oid *func_select_candidate(int nargs, Oid *input_typeids, CandidateList candidates); static int agg_get_candidates(char *aggname, Oid typeId, CandidateList *candidates); static Oid agg_select_candidate(Oid typeid, CandidateList candidates); /* ** ParseNestedFuncOrColumn ** Given a nested dot expression (i.e. (relation func ... attr), build up ** a tree with of Iter and Func nodes. */ Node * ParseNestedFuncOrColumn(ParseState *pstate, Attr *attr, int *curr_resno, int precedence) { List *mutator_iter; Node *retval = NULL; if (attr->paramNo != NULL) { Param *param = (Param *) transformExpr(pstate, (Node *) attr->paramNo, EXPR_RELATION_FIRST); retval = ParseFuncOrColumn(pstate, strVal(lfirst(attr->attrs)), lcons(param, NIL), false, false, curr_resno, precedence); } else { Ident *ident = makeNode(Ident); ident->name = attr->relname; ident->isRel = TRUE; retval = ParseFuncOrColumn(pstate, strVal(lfirst(attr->attrs)), lcons(ident, NIL), false, false, curr_resno, precedence); } /* Do more attributes follow this one? */ foreach(mutator_iter, lnext(attr->attrs)) { retval = ParseFuncOrColumn(pstate, strVal(lfirst(mutator_iter)), lcons(retval, NIL), false, false, curr_resno, precedence); } return retval; } static int agg_get_candidates(char *aggname, Oid typeId, CandidateList *candidates) { CandidateList current_candidate; Relation pg_aggregate_desc; HeapScanDesc pg_aggregate_scan; HeapTuple tup; Form_pg_aggregate agg; int ncandidates = 0; ScanKeyData aggKey[1]; *candidates = NULL; ScanKeyEntryInitialize(&aggKey[0], 0, Anum_pg_aggregate_aggname, F_NAMEEQ, NameGetDatum(aggname)); pg_aggregate_desc = heap_openr(AggregateRelationName, AccessShareLock); pg_aggregate_scan = heap_beginscan(pg_aggregate_desc, 0, SnapshotSelf, /* ??? */ 1, aggKey); while (HeapTupleIsValid(tup = heap_getnext(pg_aggregate_scan, 0))) { agg = (Form_pg_aggregate) GETSTRUCT(tup); current_candidate = (CandidateList) palloc(sizeof(struct _CandidateList)); current_candidate->args = (Oid *) palloc(sizeof(Oid)); current_candidate->args[0] = agg->aggbasetype; current_candidate->next = *candidates; *candidates = current_candidate; ncandidates++; } heap_endscan(pg_aggregate_scan); heap_close(pg_aggregate_desc, AccessShareLock); return ncandidates; } /* agg_get_candidates() */ /* agg_select_candidate() * * Try to choose only one candidate aggregate function from a list of * possible matches. Return value is Oid of input type of aggregate * if successful, else InvalidOid. */ static Oid agg_select_candidate(Oid typeid, CandidateList candidates) { CandidateList current_candidate; CandidateList last_candidate; Oid current_typeid; int ncandidates; CATEGORY category, current_category; /* * First look for exact matches or binary compatible matches. (Of * course exact matches shouldn't even get here, but anyway.) */ ncandidates = 0; last_candidate = NULL; for (current_candidate = candidates; current_candidate != NULL; current_candidate = current_candidate->next) { current_typeid = current_candidate->args[0]; if (current_typeid == typeid || IS_BINARY_COMPATIBLE(current_typeid, typeid)) { last_candidate = current_candidate; ncandidates++; } } if (ncandidates == 1) return last_candidate->args[0]; /* * If no luck that way, look for candidates which allow coercion and * have a preferred type. Keep all candidates if none match. */ category = TypeCategory(typeid); ncandidates = 0; last_candidate = NULL; for (current_candidate = candidates; current_candidate != NULL; current_candidate = current_candidate->next) { current_typeid = current_candidate->args[0]; current_category = TypeCategory(current_typeid); if (current_category == category && IsPreferredType(current_category, current_typeid) && can_coerce_type(1, &typeid, ¤t_typeid)) { /* only one so far? then keep it... */ if (last_candidate == NULL) { candidates = current_candidate; last_candidate = current_candidate; ncandidates = 1; } /* otherwise, keep this one too... */ else { last_candidate->next = current_candidate; last_candidate = current_candidate; ncandidates++; } } /* otherwise, don't bother keeping this one around... */ } if (last_candidate) /* terminate rebuilt list */ last_candidate->next = NULL; if (ncandidates == 1) return candidates->args[0]; return InvalidOid; } /* agg_select_candidate() */ /* * parse function */ Node * ParseFuncOrColumn(ParseState *pstate, char *funcname, List *fargs, bool agg_star, bool agg_distinct, int *curr_resno, int precedence) { Oid rettype = InvalidOid; Oid argrelid = InvalidOid; Oid funcid = InvalidOid; List *i = NIL; Node *first_arg = NULL; char *relname = NULL; char *refname = NULL; Relation rd; Oid relid; int nargs = length(fargs); Func *funcnode; Oid oid_array[FUNC_MAX_ARGS]; Oid *true_oid_array; Node *retval; bool retset; bool must_be_agg = agg_star || agg_distinct; bool could_be_agg; bool attisset = false; Oid toid = InvalidOid; Expr *expr; if (fargs) { first_arg = lfirst(fargs); if (first_arg == NULL) elog(ERROR, "Function '%s' does not allow NULL input", funcname); } /* * check for projection methods: if function takes one argument, and * that argument is a relation, param, or PQ function returning a * complex * type, then the function could be a projection. */ /* We only have one parameter, and it's not got aggregate decoration */ if (nargs == 1 && !must_be_agg) { /* Is it a plain Relation name from the parser? */ if (IsA(first_arg, Ident) && ((Ident *) first_arg)->isRel) { Ident *ident = (Ident *) first_arg; RangeTblEntry *rte; AttrNumber attnum; /* * first arg is a relation. This could be a projection. */ refname = ident->name; rte = refnameRangeTableEntry(pstate, refname); if (rte == NULL) { rte = addRangeTableEntry(pstate, refname, makeAttr(refname, NULL), FALSE, FALSE, TRUE); warnAutoRange(pstate, refname); } relname = rte->relname; relid = rte->relid; attnum = InvalidAttrNumber; /* * If the attr isn't a set, just make a var for it. If it is * a set, treat it like a function and drop through. Look * through the explicit column list first, since we now allow * column aliases. - thomas 2000-02-07 */ if (rte->eref->attrs != NULL) { List *c; /* * start counting attributes/columns from one. zero is * reserved for InvalidAttrNumber. - thomas 2000-01-27 */ int i = 1; foreach(c, rte->eref->attrs) { char *colname = strVal(lfirst(c)); /* found a match? */ if (strcmp(colname, funcname) == 0) { char *basename = get_attname(relid, i); if (basename != NULL) { funcname = basename; attnum = i; } /* * attnum was initialized to InvalidAttrNumber * earlier, so no need to reset it if the above * test fails. - thomas 2000-02-07 */ break; } i++; } if (attnum == InvalidAttrNumber) attnum = specialAttNum(funcname); } else attnum = get_attnum(relid, funcname); if (attnum != InvalidAttrNumber) { return (Node *) make_var(pstate, relid, refname, funcname); } /* else drop through - attr is a set */ } 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(pstate, funcname, first_arg, &attisset); if (attisset) { toid = exprType(first_arg); rd = heap_openr_nofail(typeidTypeName(toid)); if (RelationIsValid(rd)) { relname = RelationGetRelationName(rd); heap_close(rd, NoLock); } else elog(ERROR, "Type '%s' is not a relation type", typeidTypeName(toid)); argrelid = typeidTypeRelid(toid); /* * A projection contains either an attribute name or "*". */ if ((get_attnum(argrelid, funcname) == InvalidAttrNumber) && strcmp(funcname, "*")) elog(ERROR, "Functions on sets are not yet supported"); } if (retval) return retval; } } /* * See if it's an aggregate. */ if (must_be_agg) { /* We don't presently cope with, eg, foo(DISTINCT x,y) */ if (nargs != 1) elog(ERROR, "Aggregate functions may only have one parameter"); /* Agg's argument can't be a relation name, either */ if (IsA(first_arg, Ident) && ((Ident *) first_arg)->isRel) elog(ERROR, "Aggregate functions cannot be applied to relation names"); could_be_agg = true; } else { /* Try to parse as an aggregate if above-mentioned checks are OK */ could_be_agg = (nargs == 1) && !(IsA(first_arg, Ident) && ((Ident *) first_arg)->isRel); } if (could_be_agg) { Oid basetype = exprType(lfirst(fargs)); int ncandidates; CandidateList candidates; /* try for exact match first... */ if (SearchSysCacheTuple(AGGNAME, PointerGetDatum(funcname), ObjectIdGetDatum(basetype), 0, 0)) return (Node *) ParseAgg(pstate, funcname, basetype, fargs, agg_star, agg_distinct, precedence); /* check for aggregate-that-accepts-any-type (eg, COUNT) */ if (SearchSysCacheTuple(AGGNAME, PointerGetDatum(funcname), ObjectIdGetDatum(0), 0, 0)) return (Node *) ParseAgg(pstate, funcname, 0, fargs, agg_star, agg_distinct, precedence); /* * No exact match yet, so see if there is another entry in the * aggregate table that is compatible. - thomas 1998-12-05 */ ncandidates = agg_get_candidates(funcname, basetype, &candidates); if (ncandidates > 0) { Oid type; type = agg_select_candidate(basetype, candidates); if (OidIsValid(type)) { lfirst(fargs) = coerce_type(pstate, lfirst(fargs), basetype, type, -1); basetype = type; return (Node *) ParseAgg(pstate, funcname, basetype, fargs, agg_star, agg_distinct, precedence); } else { /* Multiple possible matches --- give up */ elog(ERROR, "Unable to select an aggregate function %s(%s)", funcname, typeidTypeName(basetype)); } } if (must_be_agg) { /* * No matching agg, but we had '*' or DISTINCT, so a plain * function could not have been meant. */ elog(ERROR, "There is no aggregate function %s(%s)", funcname, typeidTypeName(basetype)); } } /* * If we dropped through to here it's really a function (or a set, * which is implemented as a function). Extract arg type info and * transform relation name arguments into varnodes of the appropriate * form. */ MemSet(oid_array, 0, FUNC_MAX_ARGS * sizeof(Oid)); nargs = 0; foreach(i, fargs) { Node *arg = lfirst(i); if (IsA(arg, Ident) && ((Ident *) arg)->isRel) { RangeTblEntry *rte; int vnum; int sublevels_up; /* * a relation */ refname = ((Ident *) arg)->name; rte = refnameRangeTableEntry(pstate, refname); if (rte == NULL) { rte = addRangeTableEntry(pstate, refname, makeAttr(refname, NULL), FALSE, FALSE, TRUE); warnAutoRange(pstate, refname); } relname = rte->relname; vnum = refnameRangeTablePosn(pstate, rte->eref->relname, &sublevels_up); /* * for func(relname), the param to the function is the tuple * under consideration. 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. */ toid = typeTypeId(typenameType(relname)); /* replace it in the arg list */ lfirst(i) = makeVar(vnum, 0, toid, -1, sublevels_up); } else if (!attisset) toid = exprType(arg); else { /* if attisset is true, we already set toid for the single arg */ } /* * 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. */ if (nargs >= FUNC_MAX_ARGS) elog(ERROR, "Cannot pass more than %d arguments to a function", FUNC_MAX_ARGS); oid_array[nargs++] = 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. if func_get_detail returns true, the function * exists. otherwise, there was an error. */ if (attisset) { /* we know all of these fields already */ /* * We create a funcnode with a placeholder function SetEval. * SetEval() never actually gets executed. When the function * evaluation routines see it, they use the funcid projected out * from the relation as the actual function to call. Example: * retrieve (emp.mgr.name) The plan for this will scan the emp * relation, projecting out the mgr attribute, which is a funcid. * This function is then called (instead of SetEval) and "name" is * projected from its result. */ funcid = F_SETEVAL; rettype = toid; retset = true; true_oid_array = oid_array; } else { bool exists; exists = func_get_detail(funcname, nargs, oid_array, &funcid, &rettype, &retset, &true_oid_array); if (!exists) { /* * If we can't find a function (or can't find a unique * function), see if this is really a type-coercion request: * single-argument function call where the function name is a * type name. If so, and if we can do the coercion trivially, * just go ahead and do it without requiring there to be a * real function for it. * * "Trivial" coercions are ones that involve binary-compatible * types and ones that are coercing a previously-unknown-type * literal constant to a specific type. * * DO NOT try to generalize this code to nontrivial coercions, * because you'll just set up an infinite recursion between * this routine and coerce_type! We have already failed to * find a suitable "real" coercion function, so we have to * fail unless this is a coercion that coerce_type can handle * by itself. Make sure this code stays in sync with what * coerce_type does! */ if (nargs == 1) { Type tp; tp = SearchSysCacheTuple(TYPENAME, PointerGetDatum(funcname), 0, 0, 0); if (HeapTupleIsValid(tp)) { Oid sourceType = oid_array[0]; Oid targetType = typeTypeId(tp); Node *arg1 = lfirst(fargs); if ((sourceType == UNKNOWNOID && IsA(arg1, Const)) || sourceType == targetType || IS_BINARY_COMPATIBLE(sourceType, targetType)) { /* * Ah-hah, we can do it as a trivial coercion. * coerce_type can handle these cases, so why * duplicate code... */ return coerce_type(pstate, arg1, sourceType, targetType, -1); } } } /* * Oops. Time to die. * * If there is a single argument of complex type, we might be * dealing with the PostQuel notation rel.function instead of * the more usual function(rel). Give a nonspecific error * message that will cover both cases. */ if (nargs == 1) { Type tp = typeidType(oid_array[0]); if (typeTypeFlag(tp) == 'c') elog(ERROR, "No such attribute or function '%s'", funcname); } /* Else generate a detailed complaint */ func_error(NULL, funcname, nargs, oid_array, "Unable to identify a function that satisfies the " "given argument types" "\n\tYou may need to add explicit typecasts"); } } /* got it */ funcnode = makeNode(Func); funcnode->funcid = funcid; funcnode->functype = rettype; funcnode->funcisindex = false; funcnode->funcsize = 0; funcnode->func_fcache = NULL; funcnode->func_tlist = NIL; funcnode->func_planlist = NIL; /* perform the necessary typecasting */ make_arguments(pstate, nargs, fargs, oid_array, true_oid_array); /* * for functions returning base types, we want to project out the * return value. set up a target list to do that. the executor will * ignore these for c functions, and do the right thing for postquel * functions. */ if (typeidTypeRelid(rettype) == InvalidOid) funcnode->func_tlist = setup_base_tlist(rettype); /* * For sets, we want to make a targetlist to project out this * attribute of the set tuples. */ if (attisset) { if (!strcmp(funcname, "*")) funcnode->func_tlist = expandAll(pstate, relname, makeAttr(refname, NULL), curr_resno); else { funcnode->func_tlist = setup_tlist(funcname, argrelid); rettype = get_atttype(argrelid, get_attnum(argrelid, funcname)); } } /* * Special checks to disallow sequence functions with side-effects * in WHERE clauses. This is pretty much of a hack; why disallow these * when we have no way to check for side-effects of user-defined fns? */ if (funcid == F_NEXTVAL && pstate->p_in_where_clause) elog(ERROR, "Sequence function nextval is not allowed in WHERE clauses"); if (funcid == F_SETVAL && pstate->p_in_where_clause) elog(ERROR, "Sequence function setval is not allowed in WHERE clauses"); expr = makeNode(Expr); expr->typeOid = rettype; expr->opType = FUNC_EXPR; expr->oper = (Node *) funcnode; expr->args = fargs; retval = (Node *) expr; /* * if the function returns a set of values, then we need to iterate * over all the returned values in the executor, so we stick an iter * node here. if it returns a singleton, then we don't need the iter * node. */ if (retset) { Iter *iter = makeNode(Iter); iter->itertype = rettype; iter->iterexpr = retval; retval = (Node *) iter; } return retval; } /* func_get_candidates() * get a list of all argument type vectors for which a function named * funcname taking nargs arguments exists */ static CandidateList func_get_candidates(char *funcname, int nargs) { Relation heapRelation; Relation idesc; ScanKeyData skey; HeapTupleData tuple; IndexScanDesc sd; RetrieveIndexResult indexRes; Form_pg_proc pgProcP; CandidateList candidates = NULL; CandidateList current_candidate; int i; heapRelation = heap_openr(ProcedureRelationName, AccessShareLock); ScanKeyEntryInitialize(&skey, (bits16) 0x0, (AttrNumber) Anum_pg_proc_proname, (RegProcedure) F_NAMEEQ, (Datum) funcname); idesc = index_openr(ProcedureNameIndex); sd = index_beginscan(idesc, false, 1, &skey); do { indexRes = index_getnext(sd, ForwardScanDirection); if (indexRes) { Buffer buffer; tuple.t_datamcxt = NULL; tuple.t_data = NULL; tuple.t_self = indexRes->heap_iptr; heap_fetch(heapRelation, SnapshotNow, &tuple, &buffer); pfree(indexRes); if (tuple.t_data != NULL) { pgProcP = (Form_pg_proc) GETSTRUCT(&tuple); if (pgProcP->pronargs == nargs) { current_candidate = (CandidateList) palloc(sizeof(struct _CandidateList)); current_candidate->args = (Oid *) palloc(FUNC_MAX_ARGS * sizeof(Oid)); MemSet(current_candidate->args, 0, FUNC_MAX_ARGS * sizeof(Oid)); for (i = 0; i < nargs; i++) current_candidate->args[i] = pgProcP->proargtypes[i]; current_candidate->next = candidates; candidates = current_candidate; } ReleaseBuffer(buffer); } } } while (indexRes); index_endscan(sd); index_close(idesc); heap_close(heapRelation, AccessShareLock); return candidates; } /* match_argtypes() * Given a list of possible typeid arrays to a function and an array of * input typeids, produce a shortlist of those function typeid arrays * that match the input typeids (either exactly or by coercion), and * return the number of such arrays */ static int match_argtypes(int nargs, Oid *input_typeids, CandidateList function_typeids, CandidateList *candidates) /* return value */ { CandidateList current_candidate; CandidateList matching_candidate; Oid *current_typeids; int ncandidates = 0; *candidates = NULL; for (current_candidate = function_typeids; current_candidate != NULL; current_candidate = current_candidate->next) { current_typeids = current_candidate->args; if (can_coerce_type(nargs, input_typeids, current_typeids)) { matching_candidate = (CandidateList) palloc(sizeof(struct _CandidateList)); matching_candidate->args = current_typeids; matching_candidate->next = *candidates; *candidates = matching_candidate; ncandidates++; } } return ncandidates; } /* match_argtypes() */ /* func_select_candidate() * Given the input argtype array and more than one candidate * for the function argtype array, attempt to resolve the conflict. * Returns the selected argtype array if the conflict can be resolved, * otherwise returns NULL. * * By design, this is pretty similar to oper_select_candidate in parse_oper.c. * However, the calling convention is a little different: we assume the caller * already pruned away "candidates" that aren't actually coercion-compatible * with the input types, whereas oper_select_candidate must do that itself. */ static Oid * func_select_candidate(int nargs, Oid *input_typeids, CandidateList candidates) { CandidateList current_candidate; CandidateList last_candidate; Oid *current_typeids; int i; int ncandidates; int nbestMatch, nmatch; CATEGORY slot_category, current_category; Oid slot_type, current_type; /* * 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_typeids[i] != UNKNOWNOID && current_typeids[i] == input_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->args; /* * Still too many candidates? Run through all candidates and keep * those with the most matches on exact types + binary-compatible * 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_typeids[i] != UNKNOWNOID) { if (current_typeids[i] == input_typeids[i] || IS_BINARY_COMPATIBLE(current_typeids[i], input_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->args; /* * Still too many candidates? Now look for candidates which are * preferred types at the args that will require coercion. 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_typeids[i] != UNKNOWNOID) { current_category = TypeCategory(current_typeids[i]); if (current_typeids[i] == input_typeids[i] || IsPreferredType(current_category, 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->args; /* * Still too many candidates? Try assigning types for the unknown * columns. * * We do this by examining each unknown argument position to see if all * the candidates agree on the type category of that slot. If so, and * if some candidates accept the preferred type in that category, * eliminate the candidates with other input types. If we are down to * one candidate at the end, we win. * * XXX It's kinda bogus to do this left-to-right, isn't it? If we * eliminate some candidates because they are non-preferred at the * first slot, we won't notice that they didn't have the same type * category for a later slot. */ for (i = 0; i < nargs; i++) { if (input_typeids[i] == UNKNOWNOID) { slot_category = INVALID_TYPE; slot_type = InvalidOid; last_candidate = NULL; 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 == INVALID_TYPE) { slot_category = current_category; slot_type = current_type; last_candidate = current_candidate; } else if (current_category != slot_category) { /* punt if more than one category for this slot */ return NULL; } else if (current_type != slot_type) { if (IsPreferredType(slot_category, current_type)) { slot_type = current_type; /* forget all previous candidates */ candidates = current_candidate; last_candidate = current_candidate; } else if (IsPreferredType(slot_category, slot_type)) { /* forget this candidate */ if (last_candidate) last_candidate->next = current_candidate->next; else candidates = current_candidate->next; } else last_candidate = current_candidate; } else { /* keep this candidate */ last_candidate = current_candidate; } } if (last_candidate) /* terminate rebuilt list */ last_candidate->next = NULL; } } if (candidates == NULL) return NULL; /* no remaining candidates */ if (candidates->next != NULL) return NULL; /* more than one remaining candidate */ return candidates->args; } /* 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) get a vector of all possible input arg type arrays constructed * from the superclasses of the original input arg types * 2) get a list of all possible argument type arrays to the function * with given name and number of arguments * 3) 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 */ static bool func_get_detail(char *funcname, int nargs, Oid *oid_array, Oid *funcid, /* return value */ Oid *rettype, /* return value */ bool *retset, /* return value */ Oid **true_typeids) /* return value */ { HeapTuple ftup; /* attempt to find with arguments exactly as specified... */ ftup = SearchSysCacheTuple(PROCNAME, PointerGetDatum(funcname), Int32GetDatum(nargs), PointerGetDatum(oid_array), 0); if (HeapTupleIsValid(ftup)) { /* given argument types are the right ones */ *true_typeids = oid_array; } else { /* * didn't find an exact match, so now try to match up * candidates... */ CandidateList function_typeids; function_typeids = func_get_candidates(funcname, nargs); /* found something, so let's look through them... */ if (function_typeids != NULL) { Oid **input_typeid_vector = NULL; Oid *current_input_typeids; /* * First we will search with the given oid_array, then with * variants based on replacing complex types with their * inheritance ancestors. Stop as soon as any match is found. */ current_input_typeids = oid_array; do { CandidateList current_function_typeids; int ncandidates; ncandidates = match_argtypes(nargs, current_input_typeids, function_typeids, ¤t_function_typeids); /* one match only? then run with it... */ if (ncandidates == 1) { *true_typeids = current_function_typeids->args; ftup = SearchSysCacheTuple(PROCNAME, PointerGetDatum(funcname), Int32GetDatum(nargs), PointerGetDatum(*true_typeids), 0); Assert(HeapTupleIsValid(ftup)); break; } /* * multiple candidates? then better decide or throw an * error... */ if (ncandidates > 1) { *true_typeids = func_select_candidate(nargs, current_input_typeids, current_function_typeids); if (*true_typeids != NULL) { /* was able to choose a best candidate */ ftup = SearchSysCacheTuple(PROCNAME, PointerGetDatum(funcname), Int32GetDatum(nargs), PointerGetDatum(*true_typeids), 0); Assert(HeapTupleIsValid(ftup)); } /* * otherwise, ambiguous function call, so fail by * exiting loop with ftup still NULL. */ break; } /* * 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, oid_array); current_input_typeids = *input_typeid_vector++; } while (current_input_typeids != NULL); } } if (HeapTupleIsValid(ftup)) { Form_pg_proc pform = (Form_pg_proc) GETSTRUCT(ftup); *funcid = ftup->t_data->t_oid; *rettype = pform->prorettype; *retset = pform->proretset; return true; } return false; } /* func_get_detail() */ /* * argtype_inherit() -- Construct an argtype vector reflecting the * inheritance properties of the supplied argv. * * This function is used to disambiguate among functions with the * same name but different signatures. 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, reflecting the structure of the * inheritance tree above the supplied arguments. * * 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 last type array we return is all * zeroes. This will match any functions for which return types are * not defined. There are lots of these (mostly builtins) in the * catalogs. */ static Oid ** argtype_inherit(int nargs, Oid *oid_array) { Oid relid; int i; InhPaths arginh[FUNC_MAX_ARGS]; for (i = 0; i < FUNC_MAX_ARGS; i++) { if (i < nargs) { arginh[i].self = oid_array[i]; if ((relid = typeidTypeRelid(oid_array[i])) != InvalidOid) arginh[i].nsupers = find_inheritors(relid, &(arginh[i].supervec)); else { arginh[i].nsupers = 0; arginh[i].supervec = (Oid *) NULL; } } else { arginh[i].self = InvalidOid; arginh[i].nsupers = 0; arginh[i].supervec = (Oid *) NULL; } } /* return an ordered cross-product of the classes involved */ return gen_cross_product(arginh, nargs); } 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 rels 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, 0x0, Anum_pg_inherits_inhrelid, F_OIDEQ, ObjectIdGetDatum(relid)); inhscan = heap_beginscan(inhrel, 0, SnapshotNow, 1, &skey); while (HeapTupleIsValid(inhtup = heap_getnext(inhscan, 0))) { Form_pg_inherits inh = (Form_pg_inherits) GETSTRUCT(inhtup); queue = lappendi(queue, inh->inhparent); } heap_endscan(inhscan); /* pull next unvisited relid off the queue */ newrelid = false; while (queue != NIL) { relid = lfirsti(queue); queue = lnext(queue); if (!intMember(relid, visited)) { newrelid = true; break; } } if (newrelid) { visited = lappendi(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 */ Relation rd; Oid trelid; relid = lfirsti(elt); rd = heap_open(relid, NoLock); trelid = typeTypeId(typenameType(RelationGetRelationName(rd))); heap_close(rd, NoLock); *relidvec++ = trelid; } } 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; } static Oid ** gen_cross_product(InhPaths *arginh, int nargs) { int nanswers; Oid **result, **iter; Oid *oneres; int i, j; int cur[FUNC_MAX_ARGS]; nanswers = 1; for (i = 0; i < nargs; i++) { nanswers *= (arginh[i].nsupers + 2); cur[i] = 0; } iter = result = (Oid **) palloc(sizeof(Oid *) * nanswers); /* compute the cross product from right to left */ for (;;) { oneres = (Oid *) palloc(FUNC_MAX_ARGS * sizeof(Oid)); MemSet(oneres, 0, FUNC_MAX_ARGS * sizeof(Oid)); for (i = nargs - 1; i >= 0 && cur[i] > arginh[i].nsupers; i--) continue; /* if we're done, terminate with NULL pointer */ if (i < 0) { *iter = NULL; return result; } /* no, increment this column and zero the ones after it */ cur[i] = cur[i] + 1; for (j = nargs - 1; j > i; j--) cur[j] = 0; for (i = 0; i < nargs; i++) { if (cur[i] == 0) oneres[i] = arginh[i].self; else if (cur[i] > arginh[i].nsupers) oneres[i] = 0; /* wild card */ else oneres[i] = arginh[i].supervec[cur[i] - 1]; } *iter++ = oneres; } } /* * 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_arguments() * Given the number and types of arguments to a function, and the * actual arguments and argument types, do the necessary typecasting. * * There are two ways an input typeid can differ from a function typeid: * 1) the input type inherits the function type, so no typecasting required * 2) the input type can be typecast into the function type * Right now, we only typecast unknowns, and that is all we check for. * * func_get_detail() now can find coercions for function arguments which * will make this function executable. So, we need to recover these * results here too. * - thomas 1998-03-25 */ static void make_arguments(ParseState *pstate, int nargs, List *fargs, Oid *input_typeids, Oid *function_typeids) { List *current_fargs; int i; for (i = 0, current_fargs = fargs; i < nargs; i++, current_fargs = lnext(current_fargs)) { /* types don't match? then force coercion using a function call... */ if (input_typeids[i] != function_typeids[i]) { lfirst(current_fargs) = coerce_type(pstate, lfirst(current_fargs), input_typeids[i], function_typeids[i], -1); } } } /* ** setup_tlist ** Build a tlist that says which attribute to project to. ** This routine is called by ParseFuncOrColumn() to set up a target list ** on a tuple parameter or return value. Due to a bug in 4.0, ** it's not possible to refer to system attributes in this case. */ static List * setup_tlist(char *attname, Oid relid) { TargetEntry *tle; Resdom *resnode; Var *varnode; Oid typeid; int32 type_mod; int attno; attno = get_attnum(relid, attname); if (attno < 0) elog(ERROR, "Cannot reference attribute '%s'" " of tuple params/return values for functions", attname); typeid = get_atttype(relid, attno); type_mod = get_atttypmod(relid, attno); resnode = makeResdom(1, typeid, type_mod, get_attname(relid, attno), 0, InvalidOid, false); varnode = makeVar(-1, attno, typeid, type_mod, 0); tle = makeTargetEntry(resnode, (Node *) varnode); return lcons(tle, NIL); } /* ** setup_base_tlist ** Build a tlist that extracts a base type from the tuple ** returned by the executor. */ List * setup_base_tlist(Oid typeid) { TargetEntry *tle; Resdom *resnode; Var *varnode; resnode = makeResdom(1, typeid, -1, "", 0, InvalidOid, false); varnode = makeVar(-1, 1, typeid, -1, 0); tle = makeTargetEntry(resnode, (Node *) varnode); return lcons(tle, NIL); } /* * ParseComplexProjection - * handles function calls with a single argument that is of complex type. * This routine returns NULL if it can't handle the projection (eg. sets). */ static Node * ParseComplexProjection(ParseState *pstate, char *funcname, Node *first_arg, bool *attisset) { Oid argtype; Oid argrelid; Relation rd; Oid relid; int attnum; switch (nodeTag(first_arg)) { case T_Iter: { Func *func; Iter *iter; iter = (Iter *) first_arg; func = (Func *) ((Expr *) iter->iterexpr)->oper; argtype = get_func_rettype(func->funcid); argrelid = typeidTypeRelid(argtype); if (argrelid && ((attnum = get_attnum(argrelid, funcname)) != InvalidAttrNumber)) { /* * the argument is a function returning a tuple, so * funcname may be a projection */ /* add a tlist to the func node and return the Iter */ rd = heap_openr_nofail(typeidTypeName(argtype)); if (RelationIsValid(rd)) { relid = RelationGetRelid(rd); func->func_tlist = setup_tlist(funcname, argrelid); iter->itertype = attnumTypeId(rd, attnum); heap_close(rd, NoLock); return (Node *) iter; } else { elog(ERROR, "Function '%s' has bad return type %d", funcname, argtype); } } else { /* drop through */ ; } break; } case T_Var: { /* * The argument is a set, so this is either a projection * or a function call on this set. */ *attisset = true; break; } case T_Expr: { Expr *expr = (Expr *) first_arg; Func *funcnode; if (expr->opType != FUNC_EXPR) break; funcnode = (Func *) expr->oper; argtype = get_func_rettype(funcnode->funcid); argrelid = typeidTypeRelid(argtype); /* * the argument is a function returning a tuple, so * funcname may be a projection */ if (argrelid && (attnum = get_attnum(argrelid, funcname)) != InvalidAttrNumber) { Expr *newexpr; /* add a tlist to the func node */ rd = heap_openr(typeidTypeName(argtype), NoLock); relid = RelationGetRelid(rd); funcnode->func_tlist = setup_tlist(funcname, argrelid); funcnode->functype = attnumTypeId(rd, attnum); newexpr = makeNode(Expr); newexpr->typeOid = funcnode->functype; newexpr->opType = FUNC_EXPR; newexpr->oper = (Node *) funcnode; newexpr->args = expr->args; heap_close(rd, NoLock); return (Node *) newexpr; } break; } case T_Param: { Param *param = (Param *) first_arg; /* * If the Param is a complex type, this could be a * projection */ rd = heap_openr_nofail(typeidTypeName(param->paramtype)); if (RelationIsValid(rd)) { relid = RelationGetRelid(rd); if ((attnum = get_attnum(relid, funcname)) != InvalidAttrNumber) { param->paramtype = attnumTypeId(rd, attnum); param->param_tlist = setup_tlist(funcname, relid); heap_close(rd, NoLock); return (Node *) param; } heap_close(rd, NoLock); } break; } default: break; } return NULL; } /* * Error message when function lookup fails that gives details of the * argument types */ void func_error(char *caller, char *funcname, int nargs, Oid *argtypes, char *msg) { char p[(NAMEDATALEN + 2) * FUNC_MAX_ARGS], *ptr; int i; ptr = p; *ptr = '\0'; for (i = 0; i < nargs; i++) { if (i) { *ptr++ = ','; *ptr++ = ' '; } if (argtypes[i] != 0) { strcpy(ptr, typeidTypeName(argtypes[i])); *(ptr + NAMEDATALEN) = '\0'; } else strcpy(ptr, "opaque"); ptr += strlen(ptr); } if (caller == NULL) { elog(ERROR, "Function '%s(%s)' does not exist%s%s", funcname, p, ((msg != NULL) ? "\n\t" : ""), ((msg != NULL) ? msg : "")); } else { elog(ERROR, "%s: function '%s(%s)' does not exist%s%s", caller, funcname, p, ((msg != NULL) ? "\n\t" : ""), ((msg != NULL) ? msg : "")); } }