/*------------------------------------------------------------------------- * * parse_func.c * handle function calls in parser * * Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * src/backend/parser/parse_func.c * *------------------------------------------------------------------------- */ #include "postgres.h" #include "access/htup_details.h" #include "catalog/pg_proc.h" #include "catalog/pg_type.h" #include "funcapi.h" #include "lib/stringinfo.h" #include "nodes/makefuncs.h" #include "nodes/nodeFuncs.h" #include "parser/parse_agg.h" #include "parser/parse_coerce.h" #include "parser/parse_func.h" #include "parser/parse_relation.h" #include "parser/parse_target.h" #include "parser/parse_type.h" #include "utils/builtins.h" #include "utils/lsyscache.h" #include "utils/syscache.h" static Oid FuncNameAsType(List *funcname); static Node *ParseComplexProjection(ParseState *pstate, char *funcname, Node *first_arg, int location); /* * 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. Conversely * a function of a single complex-type argument can be written like a * column reference, allowing functions to act like computed columns. * * 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 or variadic decoration. * Also, when is_column is true, we return NULL on failure rather than * reporting a no-such-function error. * * The argument expressions (in fargs) and filter must have been transformed * already. But the agg_order expressions, if any, have not been. */ Node * ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs, List *agg_order, Expr *agg_filter, bool agg_star, bool agg_distinct, bool func_variadic, WindowDef *over, bool is_column, int location) { Oid rettype; Oid funcid; ListCell *l; ListCell *nextl; Node *first_arg = NULL; int nargs; int nargsplusdefs; Oid actual_arg_types[FUNC_MAX_ARGS]; Oid *declared_arg_types; List *argnames; List *argdefaults; Node *retval; bool retset; int nvargs; Oid vatype; 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 (list_length(fargs) > FUNC_MAX_ARGS) ereport(ERROR, (errcode(ERRCODE_TOO_MANY_ARGUMENTS), errmsg_plural("cannot pass more than %d argument to a function", "cannot pass more than %d arguments to a function", FUNC_MAX_ARGS, FUNC_MAX_ARGS), parser_errposition(pstate, location))); /* * Extract arg type info in preparation for function lookup. * * If any arguments are Param markers of type VOID, we discard them from * the parameter list. This is a hack to allow the JDBC driver to not * have to distinguish "input" and "output" parameter symbols while * parsing function-call constructs. We can't use foreach() because we * may modify the list ... */ nargs = 0; for (l = list_head(fargs); l != NULL; l = nextl) { Node *arg = lfirst(l); Oid argtype = exprType(arg); nextl = lnext(l); if (argtype == VOIDOID && IsA(arg, Param) &&!is_column) { fargs = list_delete_ptr(fargs, arg); continue; } actual_arg_types[nargs++] = argtype; } /* * Check for named arguments; if there are any, build a list of names. * * We allow mixed notation (some named and some not), but only with all * the named parameters after all the unnamed ones. So the name list * corresponds to the last N actual parameters and we don't need any extra * bookkeeping to match things up. */ argnames = NIL; foreach(l, fargs) { Node *arg = lfirst(l); if (IsA(arg, NamedArgExpr)) { NamedArgExpr *na = (NamedArgExpr *) arg; ListCell *lc; /* Reject duplicate arg names */ foreach(lc, argnames) { if (strcmp(na->name, (char *) lfirst(lc)) == 0) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("argument name \"%s\" used more than once", na->name), parser_errposition(pstate, na->location))); } argnames = lappend(argnames, na->name); } else { if (argnames != NIL) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("positional argument cannot follow named argument"), parser_errposition(pstate, exprLocation(arg)))); } } if (fargs) { first_arg = linitial(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 or variadic decoration, nor an argument name. */ if (nargs == 1 && agg_order == NIL && agg_filter == NULL && !agg_star && !agg_distinct && over == NULL && !func_variadic && argnames == NIL && list_length(funcname) == 1) { Oid argtype = actual_arg_types[0]; if (argtype == RECORDOID || ISCOMPLEX(argtype)) { retval = ParseComplexProjection(pstate, strVal(linitial(funcname)), first_arg, location); if (retval) return retval; /* * If ParseComplexProjection doesn't recognize it as a projection, * just press on. */ } } /* * Okay, it's not a column projection, so it must really be a function. * 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. * * Note: for a named-notation or variadic function call, the reported * "true" types aren't really what is in pg_proc: the types are reordered * to match the given argument order of named arguments, and a variadic * argument is replaced by a suitable number of copies of its element * type. We'll fix up the variadic case below. We may also have to deal * with default arguments. */ fdresult = func_get_detail(funcname, fargs, argnames, nargs, actual_arg_types, !func_variadic, true, &funcid, &rettype, &retset, &nvargs, &vatype, &declared_arg_types, &argdefaults); if (fdresult == FUNCDETAIL_COERCION) { /* * We interpreted it as a type coercion. coerce_type can handle these * cases, so why duplicate code... */ return coerce_type(pstate, linitial(fargs), actual_arg_types[0], rettype, -1, COERCION_EXPLICIT, COERCE_EXPLICIT_CALL, location); } 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)), parser_errposition(pstate, location))); if (agg_distinct) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("DISTINCT specified, but %s is not an aggregate function", NameListToString(funcname)), parser_errposition(pstate, location))); if (agg_order != NIL) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("ORDER BY specified, but %s is not an aggregate function", NameListToString(funcname)), parser_errposition(pstate, location))); if (agg_filter) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("FILTER specified, but %s is not an aggregate function", NameListToString(funcname)), parser_errposition(pstate, location))); if (over) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("OVER specified, but %s is not a window function nor an aggregate function", NameListToString(funcname)), parser_errposition(pstate, location))); } else if (!(fdresult == FUNCDETAIL_AGGREGATE || fdresult == FUNCDETAIL_WINDOWFUNC)) { /* * Oops. Time to die. * * If we are dealing with the attribute notation rel.function, let the * caller handle failure. */ if (is_column) return NULL; /* * 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, argnames, actual_arg_types)), errhint("Could not choose a best candidate function. " "You might need to add explicit type casts."), parser_errposition(pstate, location))); else if (list_length(agg_order) > 1) { /* It's agg(x, ORDER BY y,z) ... perhaps misplaced ORDER BY */ ereport(ERROR, (errcode(ERRCODE_UNDEFINED_FUNCTION), errmsg("function %s does not exist", func_signature_string(funcname, nargs, argnames, actual_arg_types)), errhint("No aggregate function matches the given name and argument types. " "Perhaps you misplaced ORDER BY; ORDER BY must appear " "after all regular arguments of the aggregate."), parser_errposition(pstate, location))); } else ereport(ERROR, (errcode(ERRCODE_UNDEFINED_FUNCTION), errmsg("function %s does not exist", func_signature_string(funcname, nargs, argnames, actual_arg_types)), errhint("No function matches the given name and argument types. " "You might need to add explicit type casts."), parser_errposition(pstate, location))); } /* * If there are default arguments, we have to include their types in * actual_arg_types for the purpose of checking generic type consistency. * However, we do NOT put them into the generated parse node, because * their actual values might change before the query gets run. The * planner has to insert the up-to-date values at plan time. */ nargsplusdefs = nargs; foreach(l, argdefaults) { Node *expr = (Node *) lfirst(l); /* probably shouldn't happen ... */ if (nargsplusdefs >= FUNC_MAX_ARGS) ereport(ERROR, (errcode(ERRCODE_TOO_MANY_ARGUMENTS), errmsg_plural("cannot pass more than %d argument to a function", "cannot pass more than %d arguments to a function", FUNC_MAX_ARGS, FUNC_MAX_ARGS), parser_errposition(pstate, location))); actual_arg_types[nargsplusdefs++] = exprType(expr); } /* * enforce consistency with polymorphic 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, nargsplusdefs, rettype, false); /* perform the necessary typecasting of arguments */ make_fn_arguments(pstate, fargs, actual_arg_types, declared_arg_types); /* * If it's a variadic function call, transform the last nvargs arguments * into an array --- unless it's an "any" variadic. */ if (nvargs > 0 && declared_arg_types[nargs - 1] != ANYOID) { ArrayExpr *newa = makeNode(ArrayExpr); int non_var_args = nargs - nvargs; List *vargs; Assert(non_var_args >= 0); vargs = list_copy_tail(fargs, non_var_args); fargs = list_truncate(fargs, non_var_args); newa->elements = vargs; /* assume all the variadic arguments were coerced to the same type */ newa->element_typeid = exprType((Node *) linitial(vargs)); newa->array_typeid = get_array_type(newa->element_typeid); if (!OidIsValid(newa->array_typeid)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("could not find array type for data type %s", format_type_be(newa->element_typeid)), parser_errposition(pstate, exprLocation((Node *) vargs)))); /* array_collid will be set by parse_collate.c */ newa->multidims = false; newa->location = exprLocation((Node *) vargs); fargs = lappend(fargs, newa); } /* * When function is called with an explicit VARIADIC labeled parameter, * and the declared_arg_type is "any", then sanity check the actual * parameter type now - it must be an array. */ if (nargs > 0 && vatype == ANYOID && func_variadic) { Oid va_arr_typid = actual_arg_types[nargs - 1]; if (!OidIsValid(get_element_type(va_arr_typid))) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("VARIADIC argument must be an array"), parser_errposition(pstate, exprLocation((Node *) llast(fargs))))); } /* build the appropriate output structure */ if (fdresult == FUNCDETAIL_NORMAL) { FuncExpr *funcexpr = makeNode(FuncExpr); funcexpr->funcid = funcid; funcexpr->funcresulttype = rettype; funcexpr->funcretset = retset; funcexpr->funcvariadic = func_variadic; funcexpr->funcformat = COERCE_EXPLICIT_CALL; /* funccollid and inputcollid will be set by parse_collate.c */ funcexpr->args = fargs; funcexpr->location = location; retval = (Node *) funcexpr; } else if (fdresult == FUNCDETAIL_AGGREGATE && !over) { /* aggregate function */ Aggref *aggref = makeNode(Aggref); aggref->aggfnoid = funcid; aggref->aggtype = rettype; /* aggcollid and inputcollid will be set by parse_collate.c */ /* args, aggorder, aggdistinct will be set by transformAggregateCall */ aggref->aggfilter = agg_filter; aggref->aggstar = agg_star; aggref->aggvariadic = func_variadic; /* agglevelsup will be set by transformAggregateCall */ aggref->location = location; /* * Reject attempt to call a parameterless aggregate without (*) * syntax. This is mere pedantry but some folks insisted ... */ if (fargs == NIL && !agg_star) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("%s(*) must be used to call a parameterless aggregate function", NameListToString(funcname)), parser_errposition(pstate, location))); if (retset) ereport(ERROR, (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION), errmsg("aggregates cannot return sets"), parser_errposition(pstate, location))); /* * We might want to support named arguments later, but disallow it for * now. We'd need to figure out the parsed representation (should the * NamedArgExprs go above or below the TargetEntry nodes?) and then * teach the planner to reorder the list properly. Or maybe we could * make transformAggregateCall do that? However, if you'd also like * to allow default arguments for aggregates, we'd need to do it in * planning to avoid semantic problems. */ if (argnames != NIL) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("aggregates cannot use named arguments"), parser_errposition(pstate, location))); /* parse_agg.c does additional aggregate-specific processing */ transformAggregateCall(pstate, aggref, fargs, agg_order, agg_distinct); retval = (Node *) aggref; } else { /* window function */ WindowFunc *wfunc = makeNode(WindowFunc); /* * True window functions must be called with a window definition. */ if (!over) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("window function call requires an OVER clause"), parser_errposition(pstate, location))); wfunc->winfnoid = funcid; wfunc->wintype = rettype; /* wincollid and inputcollid will be set by parse_collate.c */ wfunc->args = fargs; /* winref will be set by transformWindowFuncCall */ wfunc->winstar = agg_star; wfunc->winagg = (fdresult == FUNCDETAIL_AGGREGATE); wfunc->aggfilter = agg_filter; wfunc->location = location; /* * agg_star is allowed for aggregate functions but distinct isn't */ if (agg_distinct) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("DISTINCT is not implemented for window functions"), parser_errposition(pstate, location))); /* * Reject attempt to call a parameterless aggregate without (*) * syntax. This is mere pedantry but some folks insisted ... */ if (wfunc->winagg && fargs == NIL && !agg_star) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("%s(*) must be used to call a parameterless aggregate function", NameListToString(funcname)), parser_errposition(pstate, location))); /* * Reject window functions which are not aggregates in the case of * FILTER. */ if (!wfunc->winagg && agg_filter) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("FILTER is not implemented in non-aggregate window functions"), parser_errposition(pstate, location))); /* * ordered aggs not allowed in windows yet */ if (agg_order != NIL) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("aggregate ORDER BY is not implemented for window functions"), parser_errposition(pstate, location))); if (retset) ereport(ERROR, (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION), errmsg("window functions cannot return sets"), parser_errposition(pstate, location))); /* parse_agg.c does additional window-func-specific processing */ transformWindowFuncCall(pstate, wfunc, over); retval = (Node *) wfunc; } 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, first_candidate, last_candidate; Oid *current_typeids; Oid current_type; int i; int ncandidates; int nbestMatch, nmatch, nunknowns; Oid input_base_typeids[FUNC_MAX_ARGS]; TYPCATEGORY slot_category[FUNC_MAX_ARGS], current_category; bool current_is_preferred; bool slot_has_preferred_type[FUNC_MAX_ARGS]; bool resolved_unknowns; /* protect local fixed-size arrays */ if (nargs > FUNC_MAX_ARGS) ereport(ERROR, (errcode(ERRCODE_TOO_MANY_ARGUMENTS), errmsg_plural("cannot pass more than %d argument to a function", "cannot pass more than %d arguments to a function", FUNC_MAX_ARGS, FUNC_MAX_ARGS))); /* * 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. * * While we're at it, count the number of unknown-type arguments for use * later. */ nunknowns = 0; for (i = 0; i < nargs; i++) { if (input_typeids[i] != UNKNOWNOID) input_base_typeids[i] = getBaseType(input_typeids[i]); else { /* no need to call getBaseType on UNKNOWNOID */ input_base_typeids[i] = UNKNOWNOID; nunknowns++; } } /* * 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 inputs. * * If there are no unknown inputs, we have no more heuristics that apply, * and must fail. */ if (nunknowns == 0) return NULL; /* failed to select a best candidate */ /* * The next step examines 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 just one candidate remains, return * that one. However, if this rule turns out to reject all candidates, * keep them all instead. */ 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] = TYPCATEGORY_INVALID; 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]; get_type_category_preferred(current_type, ¤t_category, ¤t_is_preferred); if (slot_category[i] == TYPCATEGORY_INVALID) { /* first candidate */ slot_category[i] = current_category; slot_has_preferred_type[i] = current_is_preferred; } else if (current_category == slot_category[i]) { /* more candidates in same category */ slot_has_preferred_type[i] |= current_is_preferred; } else { /* category conflict! */ if (current_category == TYPCATEGORY_STRING) { /* STRING always wins if available */ slot_category[i] = current_category; slot_has_preferred_type[i] = current_is_preferred; } else { /* * Remember conflict, but keep going (might find STRING) */ have_conflict = true; } } } if (have_conflict && slot_category[i] != TYPCATEGORY_STRING) { /* Failed to resolve category conflict at this position */ resolved_unknowns = false; break; } } if (resolved_unknowns) { /* Strip non-matching candidates */ ncandidates = 0; first_candidate = candidates; 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]; get_type_category_preferred(current_type, ¤t_category, ¤t_is_preferred); if (current_category != slot_category[i]) { keepit = false; break; } if (slot_has_preferred_type[i] && !current_is_preferred) { 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 first_candidate = current_candidate->next; } } /* if we found any matches, restrict our attention to those */ if (last_candidate) { candidates = first_candidate; /* terminate rebuilt list */ last_candidate->next = NULL; } if (ncandidates == 1) return candidates; } /* * Last gasp: if there are both known- and unknown-type inputs, and all * the known types are the same, assume the unknown inputs are also that * type, and see if that gives us a unique match. If so, use that match. * * NOTE: for a binary operator with one unknown and one non-unknown input, * we already tried this heuristic in binary_oper_exact(). However, that * code only finds exact matches, whereas here we will handle matches that * involve coercion, polymorphic type resolution, etc. */ if (nunknowns < nargs) { Oid known_type = UNKNOWNOID; for (i = 0; i < nargs; i++) { if (input_base_typeids[i] == UNKNOWNOID) continue; if (known_type == UNKNOWNOID) /* first known arg? */ known_type = input_base_typeids[i]; else if (known_type != input_base_typeids[i]) { /* oops, not all match */ known_type = UNKNOWNOID; break; } } if (known_type != UNKNOWNOID) { /* okay, just one known type, apply the heuristic */ for (i = 0; i < nargs; i++) input_base_typeids[i] = known_type; ncandidates = 0; last_candidate = NULL; for (current_candidate = candidates; current_candidate != NULL; current_candidate = current_candidate->next) { current_typeids = current_candidate->args; if (can_coerce_type(nargs, input_base_typeids, current_typeids, COERCION_IMPLICIT)) { if (++ncandidates > 1) break; /* not unique, give up */ last_candidate = current_candidate; } } if (ncandidates == 1) { /* successfully identified a unique match */ last_candidate->next = NULL; return last_candidate; } } } 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 type coercion request * 2) apply the ambiguous-function resolution rules * * Return values *funcid through *true_typeids receive info about the function. * If argdefaults isn't NULL, *argdefaults receives a list of any default * argument expressions that need to be added to the given arguments. * * When processing a named- or mixed-notation call (ie, fargnames isn't NIL), * the returned true_typeids and argdefaults are ordered according to the * call's argument ordering: first any positional arguments, then the named * arguments, then defaulted arguments (if needed and allowed by * expand_defaults). Some care is needed if this information is to be compared * to the function's pg_proc entry, but in practice the caller can usually * just work with the call's argument ordering. * * We rely primarily on fargnames/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 need that check made. Note also that when fargnames isn't NIL, * the fargs list must be passed if the caller wants actual argument position * information to be returned into the NamedArgExpr nodes. */ FuncDetailCode func_get_detail(List *funcname, List *fargs, List *fargnames, int nargs, Oid *argtypes, bool expand_variadic, bool expand_defaults, Oid *funcid, /* return value */ Oid *rettype, /* return value */ bool *retset, /* return value */ int *nvargs, /* return value */ Oid *vatype, /* return value */ Oid **true_typeids, /* return value */ List **argdefaults) /* optional return value */ { FuncCandidateList raw_candidates; FuncCandidateList best_candidate; /* initialize output arguments to silence compiler warnings */ *funcid = InvalidOid; *rettype = InvalidOid; *retset = false; *nvargs = 0; *true_typeids = NULL; if (argdefaults) *argdefaults = NIL; /* Get list of possible candidates from namespace search */ raw_candidates = FuncnameGetCandidates(funcname, nargs, fargnames, expand_variadic, expand_defaults); /* * 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 the coercion path is RELABELTYPE or COERCEVIAIO, 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 simple coercion, not as * "text(name(varchar))" which the code below this point is entirely * capable of selecting. * * We also treat a coercion of a previously-unknown-type literal * constant to a specific type this way. * * The reason we reject COERCION_PATH_FUNC here is that we expect the * cast implementation function to be named after the target type. * Thus the function will be found by normal lookup if appropriate. * * The reason we reject COERCION_PATH_ARRAYCOERCE is mainly that you * can't write "foo[] (something)" as a function call. In theory * someone might want to invoke it as "_foo (something)" but we have * never supported that historically, so we can insist that people * write it as a normal cast instead. * * We also reject the specific case of COERCEVIAIO for a composite * source type and a string-category target type. This is a case that * find_coercion_pathway() allows by default, but experience has shown * that it's too commonly invoked by mistake. So, again, insist that * people use cast syntax if they want to do that. * * NB: it's important that this code does not exceed 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 && fargnames == NIL) { Oid targetType = FuncNameAsType(funcname); if (OidIsValid(targetType)) { Oid sourceType = argtypes[0]; Node *arg1 = linitial(fargs); bool iscoercion; if (sourceType == UNKNOWNOID && IsA(arg1, Const)) { /* always treat typename('literal') as coercion */ iscoercion = true; } else { CoercionPathType cpathtype; Oid cfuncid; cpathtype = find_coercion_pathway(targetType, sourceType, COERCION_EXPLICIT, &cfuncid); switch (cpathtype) { case COERCION_PATH_RELABELTYPE: iscoercion = true; break; case COERCION_PATH_COERCEVIAIO: if ((sourceType == RECORDOID || ISCOMPLEX(sourceType)) && TypeCategory(targetType) == TYPCATEGORY_STRING) iscoercion = false; else iscoercion = true; break; default: iscoercion = false; break; } } if (iscoercion) { /* Treat it as a type coercion */ *funcid = InvalidOid; *rettype = targetType; *retset = false; *nvargs = 0; *true_typeids = argtypes; return FUNCDETAIL_COERCION; } } } /* * didn't find an exact match, so now try to match up candidates... */ if (raw_candidates != NULL) { FuncCandidateList current_candidates; int ncandidates; ncandidates = func_match_argtypes(nargs, argtypes, raw_candidates, ¤t_candidates); /* one match only? then run with it... */ if (ncandidates == 1) best_candidate = current_candidates; /* * multiple candidates? then better decide or throw an error... */ else if (ncandidates > 1) { best_candidate = func_select_candidate(nargs, argtypes, current_candidates); /* * If we were able to choose a best candidate, we're done. * Otherwise, ambiguous function call. */ if (!best_candidate) return FUNCDETAIL_MULTIPLE; } } } if (best_candidate) { HeapTuple ftup; Form_pg_proc pform; FuncDetailCode result; /* * If processing named args or expanding variadics or defaults, the * "best candidate" might represent multiple equivalently good * functions; treat this case as ambiguous. */ if (!OidIsValid(best_candidate->oid)) return FUNCDETAIL_MULTIPLE; /* * We disallow VARIADIC with named arguments unless the last argument * (the one with VARIADIC attached) actually matched the variadic * parameter. This is mere pedantry, really, but some folks insisted. */ if (fargnames != NIL && !expand_variadic && nargs > 0 && best_candidate->argnumbers[nargs - 1] != nargs - 1) return FUNCDETAIL_NOTFOUND; *funcid = best_candidate->oid; *nvargs = best_candidate->nvargs; *true_typeids = best_candidate->args; /* * If processing named args, return actual argument positions into * NamedArgExpr nodes in the fargs list. This is a bit ugly but not * worth the extra notation needed to do it differently. */ if (best_candidate->argnumbers != NULL) { int i = 0; ListCell *lc; foreach(lc, fargs) { NamedArgExpr *na = (NamedArgExpr *) lfirst(lc); if (IsA(na, NamedArgExpr)) na->argnumber = best_candidate->argnumbers[i]; i++; } } ftup = SearchSysCache1(PROCOID, ObjectIdGetDatum(best_candidate->oid)); 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; *vatype = pform->provariadic; /* fetch default args if caller wants 'em */ if (argdefaults && best_candidate->ndargs > 0) { Datum proargdefaults; bool isnull; char *str; List *defaults; /* shouldn't happen, FuncnameGetCandidates messed up */ if (best_candidate->ndargs > pform->pronargdefaults) elog(ERROR, "not enough default arguments"); proargdefaults = SysCacheGetAttr(PROCOID, ftup, Anum_pg_proc_proargdefaults, &isnull); Assert(!isnull); str = TextDatumGetCString(proargdefaults); defaults = (List *) stringToNode(str); Assert(IsA(defaults, List)); pfree(str); /* Delete any unused defaults from the returned list */ if (best_candidate->argnumbers != NULL) { /* * This is a bit tricky in named notation, since the supplied * arguments could replace any subset of the defaults. We * work by making a bitmapset of the argnumbers of defaulted * arguments, then scanning the defaults list and selecting * the needed items. (This assumes that defaulted arguments * should be supplied in their positional order.) */ Bitmapset *defargnumbers; int *firstdefarg; List *newdefaults; ListCell *lc; int i; defargnumbers = NULL; firstdefarg = &best_candidate->argnumbers[best_candidate->nargs - best_candidate->ndargs]; for (i = 0; i < best_candidate->ndargs; i++) defargnumbers = bms_add_member(defargnumbers, firstdefarg[i]); newdefaults = NIL; i = pform->pronargs - pform->pronargdefaults; foreach(lc, defaults) { if (bms_is_member(i, defargnumbers)) newdefaults = lappend(newdefaults, lfirst(lc)); i++; } Assert(list_length(newdefaults) == best_candidate->ndargs); bms_free(defargnumbers); *argdefaults = newdefaults; } else { /* * Defaults for positional notation are lots easier; just * remove any unwanted ones from the front. */ int ndelete; ndelete = list_length(defaults) - best_candidate->ndargs; while (ndelete-- > 0) defaults = list_delete_first(defaults); *argdefaults = defaults; } } if (pform->proisagg) result = FUNCDETAIL_AGGREGATE; else if (pform->proiswindow) result = FUNCDETAIL_WINDOWFUNC; else result = FUNCDETAIL_NORMAL; ReleaseSysCache(ftup); return result; } return FUNCDETAIL_NOTFOUND; } /* * 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) { ListCell *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]) { Node *node = (Node *) lfirst(current_fargs); /* * If arg is a NamedArgExpr, coerce its input expr instead --- we * want the NamedArgExpr to stay at the top level of the list. */ if (IsA(node, NamedArgExpr)) { NamedArgExpr *na = (NamedArgExpr *) node; node = coerce_type(pstate, (Node *) na->arg, actual_arg_types[i], declared_arg_types[i], -1, COERCION_IMPLICIT, COERCE_IMPLICIT_CAST, -1); na->arg = (Expr *) node; } else { node = coerce_type(pstate, node, actual_arg_types[i], declared_arg_types[i], -1, COERCION_IMPLICIT, COERCE_IMPLICIT_CAST, -1); lfirst(current_fargs) = node; } } i++; } } /* * FuncNameAsType - * convenience routine to see if a function name matches a type name * * Returns the OID of the matching type, or InvalidOid if none. We ignore * shell types and complex types. */ static Oid FuncNameAsType(List *funcname) { Oid result; Type typtup; typtup = LookupTypeName(NULL, makeTypeNameFromNameList(funcname), NULL); if (typtup == NULL) return InvalidOid; if (((Form_pg_type) GETSTRUCT(typtup))->typisdefined && !OidIsValid(typeTypeRelid(typtup))) result = typeTypeId(typtup); else result = InvalidOid; ReleaseSysCache(typtup); return result; } /* * 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. */ static Node * ParseComplexProjection(ParseState *pstate, char *funcname, Node *first_arg, int location) { TupleDesc tupdesc; int i; /* * Special case for whole-row Vars so that we can resolve (foo.*).bar even * when foo is a reference to a subselect, join, or RECORD function. A * bonus is that we avoid generating an unnecessary FieldSelect; our * result can omit the whole-row Var and just be a Var for the selected * field. * * This case could be handled by expandRecordVariable, but it's more * efficient to do it this way when possible. */ if (IsA(first_arg, Var) && ((Var *) first_arg)->varattno == InvalidAttrNumber) { RangeTblEntry *rte; rte = GetRTEByRangeTablePosn(pstate, ((Var *) first_arg)->varno, ((Var *) first_arg)->varlevelsup); /* Return a Var if funcname matches a column, else NULL */ return scanRTEForColumn(pstate, rte, funcname, location); } /* * Else do it the hard way with get_expr_result_type(). * * If it's a Var of type RECORD, we have to work even harder: we have to * find what the Var refers to, and pass that to get_expr_result_type. * That task is handled by expandRecordVariable(). */ if (IsA(first_arg, Var) && ((Var *) first_arg)->vartype == RECORDOID) tupdesc = expandRecordVariable(pstate, (Var *) first_arg, 0); else if (get_expr_result_type(first_arg, NULL, &tupdesc) != TYPEFUNC_COMPOSITE) return NULL; /* unresolvable RECORD type */ Assert(tupdesc); for (i = 0; i < tupdesc->natts; i++) { Form_pg_attribute att = tupdesc->attrs[i]; if (strcmp(funcname, NameStr(att->attname)) == 0 && !att->attisdropped) { /* Success, so generate a FieldSelect expression */ FieldSelect *fselect = makeNode(FieldSelect); fselect->arg = (Expr *) first_arg; fselect->fieldnum = i + 1; fselect->resulttype = att->atttypid; fselect->resulttypmod = att->atttypmod; /* save attribute's collation for parse_collate.c */ fselect->resultcollid = att->attcollation; return (Node *) fselect; } } return NULL; /* funcname does not match any column */ } /* * funcname_signature_string * Build a string representing a function name, including arg types. * The result is something like "foo(integer)". * * If argnames isn't NIL, it is a list of C strings representing the actual * arg names for the last N arguments. This must be considered part of the * function signature too, when dealing with named-notation function calls. * * This is typically used in the construction of function-not-found error * messages. */ const char * funcname_signature_string(const char *funcname, int nargs, List *argnames, const Oid *argtypes) { StringInfoData argbuf; int numposargs; ListCell *lc; int i; initStringInfo(&argbuf); appendStringInfo(&argbuf, "%s(", funcname); numposargs = nargs - list_length(argnames); lc = list_head(argnames); for (i = 0; i < nargs; i++) { if (i) appendStringInfoString(&argbuf, ", "); if (i >= numposargs) { appendStringInfo(&argbuf, "%s := ", (char *) lfirst(lc)); lc = lnext(lc); } 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, List *argnames, const Oid *argtypes) { return funcname_signature_string(NameListToString(funcname), nargs, argnames, argtypes); } /* * 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, NIL, false, false); 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, NIL, argtypes)))); return InvalidOid; } /* * LookupTypeNameOid * Convenience routine to look up a type, silently accepting shell types */ static Oid LookupTypeNameOid(const TypeName *typename) { Oid result; Type typtup; typtup = LookupTypeName(NULL, typename, NULL); if (typtup == NULL) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("type \"%s\" does not exist", TypeNameToString(typename)))); result = typeTypeId(typtup); ReleaseSysCache(typtup); return result; } /* * 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; ListCell *args_item; argcount = list_length(argtypes); if (argcount > FUNC_MAX_ARGS) ereport(ERROR, (errcode(ERRCODE_TOO_MANY_ARGUMENTS), errmsg_plural("functions cannot have more than %d argument", "functions cannot have more than %d arguments", FUNC_MAX_ARGS, FUNC_MAX_ARGS))); args_item = list_head(argtypes); for (i = 0; i < argcount; i++) { TypeName *t = (TypeName *) lfirst(args_item); argoids[i] = LookupTypeNameOid(t); args_item = lnext(args_item); } return LookupFuncName(funcname, argcount, argoids, noError); } /* * LookupAggNameTypeNames * Find an aggregate function given a name and list of TypeName nodes. * * This is almost like LookupFuncNameTypeNames, but the error messages refer * to aggregates rather than plain functions, and we verify that the found * function really is an aggregate. */ Oid LookupAggNameTypeNames(List *aggname, List *argtypes, bool noError) { Oid argoids[FUNC_MAX_ARGS]; int argcount; int i; ListCell *lc; Oid oid; HeapTuple ftup; Form_pg_proc pform; argcount = list_length(argtypes); if (argcount > FUNC_MAX_ARGS) ereport(ERROR, (errcode(ERRCODE_TOO_MANY_ARGUMENTS), errmsg_plural("functions cannot have more than %d argument", "functions cannot have more than %d arguments", FUNC_MAX_ARGS, FUNC_MAX_ARGS))); i = 0; foreach(lc, argtypes) { TypeName *t = (TypeName *) lfirst(lc); argoids[i] = LookupTypeNameOid(t); i++; } oid = LookupFuncName(aggname, argcount, argoids, true); if (!OidIsValid(oid)) { if (noError) return InvalidOid; if (argcount == 0) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_FUNCTION), errmsg("aggregate %s(*) does not exist", NameListToString(aggname)))); else ereport(ERROR, (errcode(ERRCODE_UNDEFINED_FUNCTION), errmsg("aggregate %s does not exist", func_signature_string(aggname, argcount, NIL, argoids)))); } /* Make sure it's an aggregate */ ftup = SearchSysCache1(PROCOID, ObjectIdGetDatum(oid)); 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 is not an aggregate", func_signature_string(aggname, argcount, NIL, argoids)))); } ReleaseSysCache(ftup); return oid; }