/*------------------------------------------------------------------------- * * parse_coerce.c * handle type coercions/conversions for parser * * Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * src/backend/parser/parse_coerce.c * *------------------------------------------------------------------------- */ #include "postgres.h" #include "access/htup_details.h" #include "catalog/pg_cast.h" #include "catalog/pg_class.h" #include "catalog/pg_inherits.h" #include "catalog/pg_proc.h" #include "catalog/pg_type.h" #include "nodes/makefuncs.h" #include "nodes/nodeFuncs.h" #include "parser/parse_coerce.h" #include "parser/parse_relation.h" #include "parser/parse_type.h" #include "utils/builtins.h" #include "utils/datum.h" #include "utils/lsyscache.h" #include "utils/syscache.h" #include "utils/typcache.h" static Node *coerce_type_typmod(Node *node, Oid targetTypeId, int32 targetTypMod, CoercionContext ccontext, CoercionForm cformat, int location, bool hideInputCoercion); static void hide_coercion_node(Node *node); static Node *build_coercion_expression(Node *node, CoercionPathType pathtype, Oid funcId, Oid targetTypeId, int32 targetTypMod, CoercionContext ccontext, CoercionForm cformat, int location); static Node *coerce_record_to_complex(ParseState *pstate, Node *node, Oid targetTypeId, CoercionContext ccontext, CoercionForm cformat, int location); static bool is_complex_array(Oid typid); static bool typeIsOfTypedTable(Oid reltypeId, Oid reloftypeId); /* * coerce_to_target_type() * Convert an expression to a target type and typmod. * * This is the general-purpose entry point for arbitrary type coercion * operations. Direct use of the component operations can_coerce_type, * coerce_type, and coerce_type_typmod should be restricted to special * cases (eg, when the conversion is expected to succeed). * * Returns the possibly-transformed expression tree, or NULL if the type * conversion is not possible. (We do this, rather than ereport'ing directly, * so that callers can generate custom error messages indicating context.) * * pstate - parse state (can be NULL, see coerce_type) * expr - input expression tree (already transformed by transformExpr) * exprtype - result type of expr * targettype - desired result type * targettypmod - desired result typmod * ccontext, cformat - context indicators to control coercions * location - parse location of the coercion request, or -1 if unknown/implicit */ Node * coerce_to_target_type(ParseState *pstate, Node *expr, Oid exprtype, Oid targettype, int32 targettypmod, CoercionContext ccontext, CoercionForm cformat, int location) { Node *result; Node *origexpr; if (!can_coerce_type(1, &exprtype, &targettype, ccontext)) return NULL; /* * If the input has a CollateExpr at the top, strip it off, perform the * coercion, and put a new one back on. This is annoying since it * duplicates logic in coerce_type, but if we don't do this then it's too * hard to tell whether coerce_type actually changed anything, and we * *must* know that to avoid possibly calling hide_coercion_node on * something that wasn't generated by coerce_type. Note that if there are * multiple stacked CollateExprs, we just discard all but the topmost. * Also, if the target type isn't collatable, we discard the CollateExpr. */ origexpr = expr; while (expr && IsA(expr, CollateExpr)) expr = (Node *) ((CollateExpr *) expr)->arg; result = coerce_type(pstate, expr, exprtype, targettype, targettypmod, ccontext, cformat, location); /* * If the target is a fixed-length type, it may need a length coercion as * well as a type coercion. If we find ourselves adding both, force the * inner coercion node to implicit display form. */ result = coerce_type_typmod(result, targettype, targettypmod, ccontext, cformat, location, (result != expr && !IsA(result, Const))); if (expr != origexpr && type_is_collatable(targettype)) { /* Reinstall top CollateExpr */ CollateExpr *coll = (CollateExpr *) origexpr; CollateExpr *newcoll = makeNode(CollateExpr); newcoll->arg = (Expr *) result; newcoll->collOid = coll->collOid; newcoll->location = coll->location; result = (Node *) newcoll; } return result; } /* * coerce_type() * Convert an expression to a different type. * * The caller should already have determined that the coercion is possible; * see can_coerce_type. * * Normally, no coercion to a typmod (length) is performed here. The caller * must call coerce_type_typmod as well, if a typmod constraint is wanted. * (But if the target type is a domain, it may internally contain a * typmod constraint, which will be applied inside coerce_to_domain.) * In some cases pg_cast specifies a type coercion function that also * applies length conversion, and in those cases only, the result will * already be properly coerced to the specified typmod. * * pstate is only used in the case that we are able to resolve the type of * a previously UNKNOWN Param. It is okay to pass pstate = NULL if the * caller does not want type information updated for Params. * * Note: this function must not modify the given expression tree, only add * decoration on top of it. See transformSetOperationTree, for example. */ Node * coerce_type(ParseState *pstate, Node *node, Oid inputTypeId, Oid targetTypeId, int32 targetTypeMod, CoercionContext ccontext, CoercionForm cformat, int location) { Node *result; CoercionPathType pathtype; Oid funcId; if (targetTypeId == inputTypeId || node == NULL) { /* no conversion needed */ return node; } if (targetTypeId == ANYOID || targetTypeId == ANYELEMENTOID || targetTypeId == ANYNONARRAYOID) { /* * Assume can_coerce_type verified that implicit coercion is okay. * * Note: by returning the unmodified node here, we are saying that * it's OK to treat an UNKNOWN constant as a valid input for a * function accepting ANY, ANYELEMENT, or ANYNONARRAY. This should be * all right, since an UNKNOWN value is still a perfectly valid Datum. * * NB: we do NOT want a RelabelType here: the exposed type of the * function argument must be its actual type, not the polymorphic * pseudotype. */ return node; } if (targetTypeId == ANYARRAYOID || targetTypeId == ANYENUMOID || targetTypeId == ANYRANGEOID) { /* * Assume can_coerce_type verified that implicit coercion is okay. * * These cases are unlike the ones above because the exposed type of * the argument must be an actual array, enum, or range type. In * particular the argument must *not* be an UNKNOWN constant. If it * is, we just fall through; below, we'll call anyarray_in, * anyenum_in, or anyrange_in, which will produce an error. Also, if * what we have is a domain over array, enum, or range, we have to * relabel it to its base type. * * Note: currently, we can't actually see a domain-over-enum here, * since the other functions in this file will not match such a * parameter to ANYENUM. But that should get changed eventually. */ if (inputTypeId != UNKNOWNOID) { Oid baseTypeId = getBaseType(inputTypeId); if (baseTypeId != inputTypeId) { RelabelType *r = makeRelabelType((Expr *) node, baseTypeId, -1, InvalidOid, cformat); r->location = location; return (Node *) r; } /* Not a domain type, so return it as-is */ return node; } } if (inputTypeId == UNKNOWNOID && IsA(node, Const)) { /* * Input is a string constant with previously undetermined type. Apply * the target type's typinput function to it to produce a constant of * the target type. * * NOTE: this case cannot be folded together with the other * constant-input case, since the typinput function does not * necessarily behave the same as a type conversion function. For * example, int4's typinput function will reject "1.2", whereas * float-to-int type conversion will round to integer. * * XXX if the typinput function is not immutable, we really ought to * postpone evaluation of the function call until runtime. But there * is no way to represent a typinput function call as an expression * tree, because C-string values are not Datums. (XXX This *is* * possible as of 7.3, do we want to do it?) */ Const *con = (Const *) node; Const *newcon = makeNode(Const); Oid baseTypeId; int32 baseTypeMod; int32 inputTypeMod; Type baseType; ParseCallbackState pcbstate; /* * If the target type is a domain, we want to call its base type's * input routine, not domain_in(). This is to avoid premature failure * when the domain applies a typmod: existing input routines follow * implicit-coercion semantics for length checks, which is not always * what we want here. The needed check will be applied properly * inside coerce_to_domain(). */ baseTypeMod = targetTypeMod; baseTypeId = getBaseTypeAndTypmod(targetTypeId, &baseTypeMod); /* * For most types we pass typmod -1 to the input routine, because * existing input routines follow implicit-coercion semantics for * length checks, which is not always what we want here. Any length * constraint will be applied later by our caller. An exception * however is the INTERVAL type, for which we *must* pass the typmod * or it won't be able to obey the bizarre SQL-spec input rules. (Ugly * as sin, but so is this part of the spec...) */ if (baseTypeId == INTERVALOID) inputTypeMod = baseTypeMod; else inputTypeMod = -1; baseType = typeidType(baseTypeId); newcon->consttype = baseTypeId; newcon->consttypmod = inputTypeMod; newcon->constcollid = typeTypeCollation(baseType); newcon->constlen = typeLen(baseType); newcon->constbyval = typeByVal(baseType); newcon->constisnull = con->constisnull; /* * We use the original literal's location regardless of the position * of the coercion. This is a change from pre-9.2 behavior, meant to * simplify life for pg_stat_statements. */ newcon->location = con->location; /* * Set up to point at the constant's text if the input routine throws * an error. */ setup_parser_errposition_callback(&pcbstate, pstate, con->location); /* * We assume here that UNKNOWN's internal representation is the same * as CSTRING. */ if (!con->constisnull) newcon->constvalue = stringTypeDatum(baseType, DatumGetCString(con->constvalue), inputTypeMod); else newcon->constvalue = stringTypeDatum(baseType, NULL, inputTypeMod); /* * If it's a varlena value, force it to be in non-expanded * (non-toasted) format; this avoids any possible dependency on * external values and improves consistency of representation. */ if (!con->constisnull && newcon->constlen == -1) newcon->constvalue = PointerGetDatum(PG_DETOAST_DATUM(newcon->constvalue)); #ifdef RANDOMIZE_ALLOCATED_MEMORY /* * For pass-by-reference data types, repeat the conversion to see if * the input function leaves any uninitialized bytes in the result. We * can only detect that reliably if RANDOMIZE_ALLOCATED_MEMORY is * enabled, so we don't bother testing otherwise. The reason we don't * want any instability in the input function is that comparison of * Const nodes relies on bytewise comparison of the datums, so if the * input function leaves garbage then subexpressions that should be * identical may not get recognized as such. See pgsql-hackers * discussion of 2008-04-04. */ if (!con->constisnull && !newcon->constbyval) { Datum val2; val2 = stringTypeDatum(baseType, DatumGetCString(con->constvalue), inputTypeMod); if (newcon->constlen == -1) val2 = PointerGetDatum(PG_DETOAST_DATUM(val2)); if (!datumIsEqual(newcon->constvalue, val2, false, newcon->constlen)) elog(WARNING, "type %s has unstable input conversion for \"%s\"", typeTypeName(baseType), DatumGetCString(con->constvalue)); } #endif cancel_parser_errposition_callback(&pcbstate); result = (Node *) newcon; /* If target is a domain, apply constraints. */ if (baseTypeId != targetTypeId) result = coerce_to_domain(result, baseTypeId, baseTypeMod, targetTypeId, ccontext, cformat, location, false); ReleaseSysCache(baseType); return result; } if (IsA(node, Param) && pstate != NULL && pstate->p_coerce_param_hook != NULL) { /* * Allow the CoerceParamHook to decide what happens. It can return a * transformed node (very possibly the same Param node), or return * NULL to indicate we should proceed with normal coercion. */ result = pstate->p_coerce_param_hook(pstate, (Param *) node, targetTypeId, targetTypeMod, location); if (result) return result; } if (IsA(node, CollateExpr)) { /* * If we have a COLLATE clause, we have to push the coercion * underneath the COLLATE; or discard the COLLATE if the target type * isn't collatable. This is really ugly, but there is little choice * because the above hacks on Consts and Params wouldn't happen * otherwise. This kluge has consequences in coerce_to_target_type. */ CollateExpr *coll = (CollateExpr *) node; result = coerce_type(pstate, (Node *) coll->arg, inputTypeId, targetTypeId, targetTypeMod, ccontext, cformat, location); if (type_is_collatable(targetTypeId)) { CollateExpr *newcoll = makeNode(CollateExpr); newcoll->arg = (Expr *) result; newcoll->collOid = coll->collOid; newcoll->location = coll->location; result = (Node *) newcoll; } return result; } pathtype = find_coercion_pathway(targetTypeId, inputTypeId, ccontext, &funcId); if (pathtype != COERCION_PATH_NONE) { if (pathtype != COERCION_PATH_RELABELTYPE) { /* * Generate an expression tree representing run-time application * of the conversion function. If we are dealing with a domain * target type, the conversion function will yield the base type, * and we need to extract the correct typmod to use from the * domain's typtypmod. */ Oid baseTypeId; int32 baseTypeMod; baseTypeMod = targetTypeMod; baseTypeId = getBaseTypeAndTypmod(targetTypeId, &baseTypeMod); result = build_coercion_expression(node, pathtype, funcId, baseTypeId, baseTypeMod, ccontext, cformat, location); /* * If domain, coerce to the domain type and relabel with domain * type ID, hiding the previous coercion node. */ if (targetTypeId != baseTypeId) result = coerce_to_domain(result, baseTypeId, baseTypeMod, targetTypeId, ccontext, cformat, location, true); } else { /* * We don't need to do a physical conversion, but we do need to * attach a RelabelType node so that the expression will be seen * to have the intended type when inspected by higher-level code. * * Also, domains may have value restrictions beyond the base type * that must be accounted for. If the destination is a domain * then we won't need a RelabelType node. */ result = coerce_to_domain(node, InvalidOid, -1, targetTypeId, ccontext, cformat, location, false); if (result == node) { /* * XXX could we label result with exprTypmod(node) instead of * default -1 typmod, to save a possible length-coercion * later? Would work if both types have same interpretation of * typmod, which is likely but not certain. */ RelabelType *r = makeRelabelType((Expr *) result, targetTypeId, -1, InvalidOid, cformat); r->location = location; result = (Node *) r; } } return result; } if (inputTypeId == RECORDOID && ISCOMPLEX(targetTypeId)) { /* Coerce a RECORD to a specific complex type */ return coerce_record_to_complex(pstate, node, targetTypeId, ccontext, cformat, location); } if (targetTypeId == RECORDOID && ISCOMPLEX(inputTypeId)) { /* Coerce a specific complex type to RECORD */ /* NB: we do NOT want a RelabelType here */ return node; } #ifdef NOT_USED if (inputTypeId == RECORDARRAYOID && is_complex_array(targetTypeId)) { /* Coerce record[] to a specific complex array type */ /* not implemented yet ... */ } #endif if (targetTypeId == RECORDARRAYOID && is_complex_array(inputTypeId)) { /* Coerce a specific complex array type to record[] */ /* NB: we do NOT want a RelabelType here */ return node; } if (typeInheritsFrom(inputTypeId, targetTypeId) || typeIsOfTypedTable(inputTypeId, targetTypeId)) { /* * Input class type is a subclass of target, so generate an * appropriate runtime conversion (removing unneeded columns and * possibly rearranging the ones that are wanted). * * We will also get here when the input is a domain over a subclass of * the target type. To keep life simple for the executor, we define * ConvertRowtypeExpr as only working between regular composite types; * therefore, in such cases insert a RelabelType to smash the input * expression down to its base type. */ Oid baseTypeId = getBaseType(inputTypeId); ConvertRowtypeExpr *r = makeNode(ConvertRowtypeExpr); if (baseTypeId != inputTypeId) { RelabelType *rt = makeRelabelType((Expr *) node, baseTypeId, -1, InvalidOid, COERCE_IMPLICIT_CAST); rt->location = location; node = (Node *) rt; } r->arg = (Expr *) node; r->resulttype = targetTypeId; r->convertformat = cformat; r->location = location; return (Node *) r; } /* If we get here, caller blew it */ elog(ERROR, "failed to find conversion function from %s to %s", format_type_be(inputTypeId), format_type_be(targetTypeId)); return NULL; /* keep compiler quiet */ } /* * can_coerce_type() * Can input_typeids be coerced to target_typeids? * * We must be told the context (CAST construct, assignment, implicit coercion) * as this determines the set of available casts. */ bool can_coerce_type(int nargs, Oid *input_typeids, Oid *target_typeids, CoercionContext ccontext) { bool have_generics = false; int i; /* run through argument list... */ for (i = 0; i < nargs; i++) { Oid inputTypeId = input_typeids[i]; Oid targetTypeId = target_typeids[i]; CoercionPathType pathtype; Oid funcId; /* no problem if same type */ if (inputTypeId == targetTypeId) continue; /* accept if target is ANY */ if (targetTypeId == ANYOID) continue; /* accept if target is polymorphic, for now */ if (IsPolymorphicType(targetTypeId)) { have_generics = true; /* do more checking later */ continue; } /* * If input is an untyped string constant, assume we can convert it to * anything. */ if (inputTypeId == UNKNOWNOID) continue; /* * If pg_cast shows that we can coerce, accept. This test now covers * both binary-compatible and coercion-function cases. */ pathtype = find_coercion_pathway(targetTypeId, inputTypeId, ccontext, &funcId); if (pathtype != COERCION_PATH_NONE) continue; /* * If input is RECORD and target is a composite type, assume we can * coerce (may need tighter checking here) */ if (inputTypeId == RECORDOID && ISCOMPLEX(targetTypeId)) continue; /* * If input is a composite type and target is RECORD, accept */ if (targetTypeId == RECORDOID && ISCOMPLEX(inputTypeId)) continue; #ifdef NOT_USED /* not implemented yet */ /* * If input is record[] and target is a composite array type, assume * we can coerce (may need tighter checking here) */ if (inputTypeId == RECORDARRAYOID && is_complex_array(targetTypeId)) continue; #endif /* * If input is a composite array type and target is record[], accept */ if (targetTypeId == RECORDARRAYOID && is_complex_array(inputTypeId)) continue; /* * If input is a class type that inherits from target, accept */ if (typeInheritsFrom(inputTypeId, targetTypeId) || typeIsOfTypedTable(inputTypeId, targetTypeId)) continue; /* * Else, cannot coerce at this argument position */ return false; } /* If we found any generic argument types, cross-check them */ if (have_generics) { if (!check_generic_type_consistency(input_typeids, target_typeids, nargs)) return false; } return true; } /* * Create an expression tree to represent coercion to a domain type. * * 'arg': input expression * 'baseTypeId': base type of domain, if known (pass InvalidOid if caller * has not bothered to look this up) * 'baseTypeMod': base type typmod of domain, if known (pass -1 if caller * has not bothered to look this up) * 'typeId': target type to coerce to * 'ccontext': context indicator to control coercions * 'cformat': coercion display format * 'location': coercion request location * 'hideInputCoercion': if true, hide the input coercion under this one. * * If the target type isn't a domain, the given 'arg' is returned as-is. */ Node * coerce_to_domain(Node *arg, Oid baseTypeId, int32 baseTypeMod, Oid typeId, CoercionContext ccontext, CoercionForm cformat, int location, bool hideInputCoercion) { CoerceToDomain *result; /* Get the base type if it hasn't been supplied */ if (baseTypeId == InvalidOid) baseTypeId = getBaseTypeAndTypmod(typeId, &baseTypeMod); /* If it isn't a domain, return the node as it was passed in */ if (baseTypeId == typeId) return arg; /* Suppress display of nested coercion steps */ if (hideInputCoercion) hide_coercion_node(arg); /* * If the domain applies a typmod to its base type, build the appropriate * coercion step. Mark it implicit for display purposes, because we don't * want it shown separately by ruleutils.c; but the isExplicit flag passed * to the conversion function depends on the manner in which the domain * coercion is invoked, so that the semantics of implicit and explicit * coercion differ. (Is that really the behavior we want?) * * NOTE: because we apply this as part of the fixed expression structure, * ALTER DOMAIN cannot alter the typtypmod. But it's unclear that that * would be safe to do anyway, without lots of knowledge about what the * base type thinks the typmod means. */ arg = coerce_type_typmod(arg, baseTypeId, baseTypeMod, ccontext, COERCE_IMPLICIT_CAST, location, false); /* * Now build the domain coercion node. This represents run-time checking * of any constraints currently attached to the domain. This also ensures * that the expression is properly labeled as to result type. */ result = makeNode(CoerceToDomain); result->arg = (Expr *) arg; result->resulttype = typeId; result->resulttypmod = -1; /* currently, always -1 for domains */ /* resultcollid will be set by parse_collate.c */ result->coercionformat = cformat; result->location = location; return (Node *) result; } /* * coerce_type_typmod() * Force a value to a particular typmod, if meaningful and possible. * * This is applied to values that are going to be stored in a relation * (where we have an atttypmod for the column) as well as values being * explicitly CASTed (where the typmod comes from the target type spec). * * The caller must have already ensured that the value is of the correct * type, typically by applying coerce_type. * * ccontext may affect semantics, depending on whether the length coercion * function pays attention to the isExplicit flag it's passed. * * cformat determines the display properties of the generated node (if any). * * If hideInputCoercion is true *and* we generate a node, the input node is * forced to IMPLICIT display form, so that only the typmod coercion node will * be visible when displaying the expression. * * NOTE: this does not need to work on domain types, because any typmod * coercion for a domain is considered to be part of the type coercion * needed to produce the domain value in the first place. So, no getBaseType. */ static Node * coerce_type_typmod(Node *node, Oid targetTypeId, int32 targetTypMod, CoercionContext ccontext, CoercionForm cformat, int location, bool hideInputCoercion) { CoercionPathType pathtype; Oid funcId; /* Skip coercion if already done */ if (targetTypMod == exprTypmod(node)) return node; /* Suppress display of nested coercion steps */ if (hideInputCoercion) hide_coercion_node(node); pathtype = find_typmod_coercion_function(targetTypeId, &funcId); if (pathtype != COERCION_PATH_NONE) { node = build_coercion_expression(node, pathtype, funcId, targetTypeId, targetTypMod, ccontext, cformat, location); } else { /* * We don't need to perform any actual coercion step, but we should * apply a RelabelType to ensure that the expression exposes the * intended typmod. */ RelabelType *rt; rt = makeRelabelType((Expr *) node, targetTypeId, targetTypMod, exprCollation(node), cformat); rt->location = location; node = (Node *) rt; } return node; } /* * Mark a coercion node as IMPLICIT so it will never be displayed by * ruleutils.c. We use this when we generate a nest of coercion nodes * to implement what is logically one conversion; the inner nodes are * forced to IMPLICIT_CAST format. This does not change their semantics, * only display behavior. * * It is caller error to call this on something that doesn't have a * CoercionForm field. */ static void hide_coercion_node(Node *node) { if (IsA(node, FuncExpr)) ((FuncExpr *) node)->funcformat = COERCE_IMPLICIT_CAST; else if (IsA(node, RelabelType)) ((RelabelType *) node)->relabelformat = COERCE_IMPLICIT_CAST; else if (IsA(node, CoerceViaIO)) ((CoerceViaIO *) node)->coerceformat = COERCE_IMPLICIT_CAST; else if (IsA(node, ArrayCoerceExpr)) ((ArrayCoerceExpr *) node)->coerceformat = COERCE_IMPLICIT_CAST; else if (IsA(node, ConvertRowtypeExpr)) ((ConvertRowtypeExpr *) node)->convertformat = COERCE_IMPLICIT_CAST; else if (IsA(node, RowExpr)) ((RowExpr *) node)->row_format = COERCE_IMPLICIT_CAST; else if (IsA(node, CoerceToDomain)) ((CoerceToDomain *) node)->coercionformat = COERCE_IMPLICIT_CAST; else elog(ERROR, "unsupported node type: %d", (int) nodeTag(node)); } /* * build_coercion_expression() * Construct an expression tree for applying a pg_cast entry. * * This is used for both type-coercion and length-coercion operations, * since there is no difference in terms of the calling convention. */ static Node * build_coercion_expression(Node *node, CoercionPathType pathtype, Oid funcId, Oid targetTypeId, int32 targetTypMod, CoercionContext ccontext, CoercionForm cformat, int location) { int nargs = 0; if (OidIsValid(funcId)) { HeapTuple tp; Form_pg_proc procstruct; tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcId)); if (!HeapTupleIsValid(tp)) elog(ERROR, "cache lookup failed for function %u", funcId); procstruct = (Form_pg_proc) GETSTRUCT(tp); /* * These Asserts essentially check that function is a legal coercion * function. We can't make the seemingly obvious tests on prorettype * and proargtypes[0], even in the COERCION_PATH_FUNC case, because of * various binary-compatibility cases. */ /* Assert(targetTypeId == procstruct->prorettype); */ Assert(!procstruct->proretset); Assert(procstruct->prokind == PROKIND_FUNCTION); nargs = procstruct->pronargs; Assert(nargs >= 1 && nargs <= 3); /* Assert(procstruct->proargtypes.values[0] == exprType(node)); */ Assert(nargs < 2 || procstruct->proargtypes.values[1] == INT4OID); Assert(nargs < 3 || procstruct->proargtypes.values[2] == BOOLOID); ReleaseSysCache(tp); } if (pathtype == COERCION_PATH_FUNC) { /* We build an ordinary FuncExpr with special arguments */ FuncExpr *fexpr; List *args; Const *cons; Assert(OidIsValid(funcId)); args = list_make1(node); if (nargs >= 2) { /* Pass target typmod as an int4 constant */ cons = makeConst(INT4OID, -1, InvalidOid, sizeof(int32), Int32GetDatum(targetTypMod), false, true); args = lappend(args, cons); } if (nargs == 3) { /* Pass it a boolean isExplicit parameter, too */ cons = makeConst(BOOLOID, -1, InvalidOid, sizeof(bool), BoolGetDatum(ccontext == COERCION_EXPLICIT), false, true); args = lappend(args, cons); } fexpr = makeFuncExpr(funcId, targetTypeId, args, InvalidOid, InvalidOid, cformat); fexpr->location = location; return (Node *) fexpr; } else if (pathtype == COERCION_PATH_ARRAYCOERCE) { /* We need to build an ArrayCoerceExpr */ ArrayCoerceExpr *acoerce = makeNode(ArrayCoerceExpr); CaseTestExpr *ctest = makeNode(CaseTestExpr); Oid sourceBaseTypeId; int32 sourceBaseTypeMod; Oid targetElementType; Node *elemexpr; /* * Look through any domain over the source array type. Note we don't * expect that the target type is a domain; it must be a plain array. * (To get to a domain target type, we'll do coerce_to_domain later.) */ sourceBaseTypeMod = exprTypmod(node); sourceBaseTypeId = getBaseTypeAndTypmod(exprType(node), &sourceBaseTypeMod); /* * Set up a CaseTestExpr representing one element of the source array. * This is an abuse of CaseTestExpr, but it's OK as long as there * can't be any CaseExpr or ArrayCoerceExpr within the completed * elemexpr. */ ctest->typeId = get_element_type(sourceBaseTypeId); Assert(OidIsValid(ctest->typeId)); ctest->typeMod = sourceBaseTypeMod; ctest->collation = InvalidOid; /* Assume coercions don't care */ /* And coerce it to the target element type */ targetElementType = get_element_type(targetTypeId); Assert(OidIsValid(targetElementType)); elemexpr = coerce_to_target_type(NULL, (Node *) ctest, ctest->typeId, targetElementType, targetTypMod, ccontext, cformat, location); if (elemexpr == NULL) /* shouldn't happen */ elog(ERROR, "failed to coerce array element type as expected"); acoerce->arg = (Expr *) node; acoerce->elemexpr = (Expr *) elemexpr; acoerce->resulttype = targetTypeId; /* * Label the output as having a particular element typmod only if we * ended up with a per-element expression that is labeled that way. */ acoerce->resulttypmod = exprTypmod(elemexpr); /* resultcollid will be set by parse_collate.c */ acoerce->coerceformat = cformat; acoerce->location = location; return (Node *) acoerce; } else if (pathtype == COERCION_PATH_COERCEVIAIO) { /* We need to build a CoerceViaIO node */ CoerceViaIO *iocoerce = makeNode(CoerceViaIO); Assert(!OidIsValid(funcId)); iocoerce->arg = (Expr *) node; iocoerce->resulttype = targetTypeId; /* resultcollid will be set by parse_collate.c */ iocoerce->coerceformat = cformat; iocoerce->location = location; return (Node *) iocoerce; } else { elog(ERROR, "unsupported pathtype %d in build_coercion_expression", (int) pathtype); return NULL; /* keep compiler quiet */ } } /* * coerce_record_to_complex * Coerce a RECORD to a specific composite type. * * Currently we only support this for inputs that are RowExprs or whole-row * Vars. */ static Node * coerce_record_to_complex(ParseState *pstate, Node *node, Oid targetTypeId, CoercionContext ccontext, CoercionForm cformat, int location) { RowExpr *rowexpr; Oid baseTypeId; int32 baseTypeMod = -1; TupleDesc tupdesc; List *args = NIL; List *newargs; int i; int ucolno; ListCell *arg; if (node && IsA(node, RowExpr)) { /* * Since the RowExpr must be of type RECORD, we needn't worry about it * containing any dropped columns. */ args = ((RowExpr *) node)->args; } else if (node && IsA(node, Var) && ((Var *) node)->varattno == InvalidAttrNumber) { int rtindex = ((Var *) node)->varno; int sublevels_up = ((Var *) node)->varlevelsup; int vlocation = ((Var *) node)->location; RangeTblEntry *rte; rte = GetRTEByRangeTablePosn(pstate, rtindex, sublevels_up); expandRTE(rte, rtindex, sublevels_up, vlocation, false, NULL, &args); } else ereport(ERROR, (errcode(ERRCODE_CANNOT_COERCE), errmsg("cannot cast type %s to %s", format_type_be(RECORDOID), format_type_be(targetTypeId)), parser_coercion_errposition(pstate, location, node))); /* * Look up the composite type, accounting for possibility that what we are * given is a domain over composite. */ baseTypeId = getBaseTypeAndTypmod(targetTypeId, &baseTypeMod); tupdesc = lookup_rowtype_tupdesc(baseTypeId, baseTypeMod); /* Process the fields */ newargs = NIL; ucolno = 1; arg = list_head(args); for (i = 0; i < tupdesc->natts; i++) { Node *expr; Node *cexpr; Oid exprtype; Form_pg_attribute attr = TupleDescAttr(tupdesc, i); /* Fill in NULLs for dropped columns in rowtype */ if (attr->attisdropped) { /* * can't use atttypid here, but it doesn't really matter what type * the Const claims to be. */ newargs = lappend(newargs, makeNullConst(INT4OID, -1, InvalidOid)); continue; } if (arg == NULL) ereport(ERROR, (errcode(ERRCODE_CANNOT_COERCE), errmsg("cannot cast type %s to %s", format_type_be(RECORDOID), format_type_be(targetTypeId)), errdetail("Input has too few columns."), parser_coercion_errposition(pstate, location, node))); expr = (Node *) lfirst(arg); exprtype = exprType(expr); cexpr = coerce_to_target_type(pstate, expr, exprtype, attr->atttypid, attr->atttypmod, ccontext, COERCE_IMPLICIT_CAST, -1); if (cexpr == NULL) ereport(ERROR, (errcode(ERRCODE_CANNOT_COERCE), errmsg("cannot cast type %s to %s", format_type_be(RECORDOID), format_type_be(targetTypeId)), errdetail("Cannot cast type %s to %s in column %d.", format_type_be(exprtype), format_type_be(attr->atttypid), ucolno), parser_coercion_errposition(pstate, location, expr))); newargs = lappend(newargs, cexpr); ucolno++; arg = lnext(arg); } if (arg != NULL) ereport(ERROR, (errcode(ERRCODE_CANNOT_COERCE), errmsg("cannot cast type %s to %s", format_type_be(RECORDOID), format_type_be(targetTypeId)), errdetail("Input has too many columns."), parser_coercion_errposition(pstate, location, node))); ReleaseTupleDesc(tupdesc); rowexpr = makeNode(RowExpr); rowexpr->args = newargs; rowexpr->row_typeid = baseTypeId; rowexpr->row_format = cformat; rowexpr->colnames = NIL; /* not needed for named target type */ rowexpr->location = location; /* If target is a domain, apply constraints */ if (baseTypeId != targetTypeId) { rowexpr->row_format = COERCE_IMPLICIT_CAST; return coerce_to_domain((Node *) rowexpr, baseTypeId, baseTypeMod, targetTypeId, ccontext, cformat, location, false); } return (Node *) rowexpr; } /* * coerce_to_boolean() * Coerce an argument of a construct that requires boolean input * (AND, OR, NOT, etc). Also check that input is not a set. * * Returns the possibly-transformed node tree. * * As with coerce_type, pstate may be NULL if no special unknown-Param * processing is wanted. */ Node * coerce_to_boolean(ParseState *pstate, Node *node, const char *constructName) { Oid inputTypeId = exprType(node); if (inputTypeId != BOOLOID) { Node *newnode; newnode = coerce_to_target_type(pstate, node, inputTypeId, BOOLOID, -1, COERCION_ASSIGNMENT, COERCE_IMPLICIT_CAST, -1); if (newnode == NULL) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), /* translator: first %s is name of a SQL construct, eg WHERE */ errmsg("argument of %s must be type %s, not type %s", constructName, "boolean", format_type_be(inputTypeId)), parser_errposition(pstate, exprLocation(node)))); node = newnode; } if (expression_returns_set(node)) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), /* translator: %s is name of a SQL construct, eg WHERE */ errmsg("argument of %s must not return a set", constructName), parser_errposition(pstate, exprLocation(node)))); return node; } /* * coerce_to_specific_type_typmod() * Coerce an argument of a construct that requires a specific data type, * with a specific typmod. Also check that input is not a set. * * Returns the possibly-transformed node tree. * * As with coerce_type, pstate may be NULL if no special unknown-Param * processing is wanted. */ Node * coerce_to_specific_type_typmod(ParseState *pstate, Node *node, Oid targetTypeId, int32 targetTypmod, const char *constructName) { Oid inputTypeId = exprType(node); if (inputTypeId != targetTypeId) { Node *newnode; newnode = coerce_to_target_type(pstate, node, inputTypeId, targetTypeId, targetTypmod, COERCION_ASSIGNMENT, COERCE_IMPLICIT_CAST, -1); if (newnode == NULL) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), /* translator: first %s is name of a SQL construct, eg LIMIT */ errmsg("argument of %s must be type %s, not type %s", constructName, format_type_be(targetTypeId), format_type_be(inputTypeId)), parser_errposition(pstate, exprLocation(node)))); node = newnode; } if (expression_returns_set(node)) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), /* translator: %s is name of a SQL construct, eg LIMIT */ errmsg("argument of %s must not return a set", constructName), parser_errposition(pstate, exprLocation(node)))); return node; } /* * coerce_to_specific_type() * Coerce an argument of a construct that requires a specific data type. * Also check that input is not a set. * * Returns the possibly-transformed node tree. * * As with coerce_type, pstate may be NULL if no special unknown-Param * processing is wanted. */ Node * coerce_to_specific_type(ParseState *pstate, Node *node, Oid targetTypeId, const char *constructName) { return coerce_to_specific_type_typmod(pstate, node, targetTypeId, -1, constructName); } /* * parser_coercion_errposition - report coercion error location, if possible * * We prefer to point at the coercion request (CAST, ::, etc) if possible; * but there may be no such location in the case of an implicit coercion. * In that case point at the input expression. * * XXX possibly this is more generally useful than coercion errors; * if so, should rename and place with parser_errposition. */ int parser_coercion_errposition(ParseState *pstate, int coerce_location, Node *input_expr) { if (coerce_location >= 0) return parser_errposition(pstate, coerce_location); else return parser_errposition(pstate, exprLocation(input_expr)); } /* * select_common_type() * Determine the common supertype of a list of input expressions. * This is used for determining the output type of CASE, UNION, * and similar constructs. * * 'exprs' is a *nonempty* list of expressions. Note that earlier items * in the list will be preferred if there is doubt. * 'context' is a phrase to use in the error message if we fail to select * a usable type. Pass NULL to have the routine return InvalidOid * rather than throwing an error on failure. * 'which_expr': if not NULL, receives a pointer to the particular input * expression from which the result type was taken. */ Oid select_common_type(ParseState *pstate, List *exprs, const char *context, Node **which_expr) { Node *pexpr; Oid ptype; TYPCATEGORY pcategory; bool pispreferred; ListCell *lc; Assert(exprs != NIL); pexpr = (Node *) linitial(exprs); lc = lnext(list_head(exprs)); ptype = exprType(pexpr); /* * If all input types are valid and exactly the same, just pick that type. * This is the only way that we will resolve the result as being a domain * type; otherwise domains are smashed to their base types for comparison. */ if (ptype != UNKNOWNOID) { for_each_cell(lc, lc) { Node *nexpr = (Node *) lfirst(lc); Oid ntype = exprType(nexpr); if (ntype != ptype) break; } if (lc == NULL) /* got to the end of the list? */ { if (which_expr) *which_expr = pexpr; return ptype; } } /* * Nope, so set up for the full algorithm. Note that at this point, lc * points to the first list item with type different from pexpr's; we need * not re-examine any items the previous loop advanced over. */ ptype = getBaseType(ptype); get_type_category_preferred(ptype, &pcategory, &pispreferred); for_each_cell(lc, lc) { Node *nexpr = (Node *) lfirst(lc); Oid ntype = getBaseType(exprType(nexpr)); /* move on to next one if no new information... */ if (ntype != UNKNOWNOID && ntype != ptype) { TYPCATEGORY ncategory; bool nispreferred; get_type_category_preferred(ntype, &ncategory, &nispreferred); if (ptype == UNKNOWNOID) { /* so far, only unknowns so take anything... */ pexpr = nexpr; ptype = ntype; pcategory = ncategory; pispreferred = nispreferred; } else if (ncategory != pcategory) { /* * both types in different categories? then not much hope... */ if (context == NULL) return InvalidOid; ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), /*------ translator: first %s is name of a SQL construct, eg CASE */ errmsg("%s types %s and %s cannot be matched", context, format_type_be(ptype), format_type_be(ntype)), parser_errposition(pstate, exprLocation(nexpr)))); } else if (!pispreferred && can_coerce_type(1, &ptype, &ntype, COERCION_IMPLICIT) && !can_coerce_type(1, &ntype, &ptype, COERCION_IMPLICIT)) { /* * take new type if can coerce to it implicitly but not the * other way; but if we have a preferred type, stay on it. */ pexpr = nexpr; ptype = ntype; pcategory = ncategory; pispreferred = nispreferred; } } } /* * If all the inputs were UNKNOWN type --- ie, unknown-type literals --- * then resolve as type TEXT. This situation comes up with constructs * like SELECT (CASE WHEN foo THEN 'bar' ELSE 'baz' END); SELECT 'foo' * UNION SELECT 'bar'; It might seem desirable to leave the construct's * output type as UNKNOWN, but that really doesn't work, because we'd * probably end up needing a runtime coercion from UNKNOWN to something * else, and we usually won't have it. We need to coerce the unknown * literals while they are still literals, so a decision has to be made * now. */ if (ptype == UNKNOWNOID) ptype = TEXTOID; if (which_expr) *which_expr = pexpr; return ptype; } /* * coerce_to_common_type() * Coerce an expression to the given type. * * This is used following select_common_type() to coerce the individual * expressions to the desired type. 'context' is a phrase to use in the * error message if we fail to coerce. * * As with coerce_type, pstate may be NULL if no special unknown-Param * processing is wanted. */ Node * coerce_to_common_type(ParseState *pstate, Node *node, Oid targetTypeId, const char *context) { Oid inputTypeId = exprType(node); if (inputTypeId == targetTypeId) return node; /* no work */ if (can_coerce_type(1, &inputTypeId, &targetTypeId, COERCION_IMPLICIT)) node = coerce_type(pstate, node, inputTypeId, targetTypeId, -1, COERCION_IMPLICIT, COERCE_IMPLICIT_CAST, -1); else ereport(ERROR, (errcode(ERRCODE_CANNOT_COERCE), /* translator: first %s is name of a SQL construct, eg CASE */ errmsg("%s could not convert type %s to %s", context, format_type_be(inputTypeId), format_type_be(targetTypeId)), parser_errposition(pstate, exprLocation(node)))); return node; } /* * check_generic_type_consistency() * Are the actual arguments potentially compatible with a * polymorphic function? * * The argument consistency rules are: * * 1) All arguments declared ANYELEMENT must have the same datatype. * 2) All arguments declared ANYARRAY must have the same datatype, * which must be a varlena array type. * 3) All arguments declared ANYRANGE must have the same datatype, * which must be a range type. * 4) If there are arguments of both ANYELEMENT and ANYARRAY, make sure the * actual ANYELEMENT datatype is in fact the element type for the actual * ANYARRAY datatype. * 5) Similarly, if there are arguments of both ANYELEMENT and ANYRANGE, * make sure the actual ANYELEMENT datatype is in fact the subtype for * the actual ANYRANGE type. * 6) ANYENUM is treated the same as ANYELEMENT except that if it is used * (alone or in combination with plain ANYELEMENT), we add the extra * condition that the ANYELEMENT type must be an enum. * 7) ANYNONARRAY is treated the same as ANYELEMENT except that if it is used, * we add the extra condition that the ANYELEMENT type must not be an array. * (This is a no-op if used in combination with ANYARRAY or ANYENUM, but * is an extra restriction if not.) * * Domains over arrays match ANYARRAY, and are immediately flattened to their * base type. (Thus, for example, we will consider it a match if one ANYARRAY * argument is a domain over int4[] while another one is just int4[].) Also * notice that such a domain does *not* match ANYNONARRAY. * * Similarly, domains over ranges match ANYRANGE, and are immediately * flattened to their base type. * * Note that domains aren't currently considered to match ANYENUM, * even if their base type would match. * * If we have UNKNOWN input (ie, an untyped literal) for any polymorphic * argument, assume it is okay. * * If an input is of type ANYARRAY (ie, we know it's an array, but not * what element type), we will accept it as a match to an argument declared * ANYARRAY, so long as we don't have to determine an element type --- * that is, so long as there is no use of ANYELEMENT. This is mostly for * backwards compatibility with the pre-7.4 behavior of ANYARRAY. * * We do not ereport here, but just return false if a rule is violated. */ bool check_generic_type_consistency(Oid *actual_arg_types, Oid *declared_arg_types, int nargs) { int j; Oid elem_typeid = InvalidOid; Oid array_typeid = InvalidOid; Oid array_typelem; Oid range_typeid = InvalidOid; Oid range_typelem; bool have_anyelement = false; bool have_anynonarray = false; bool have_anyenum = false; /* * Loop through the arguments to see if we have any that are polymorphic. * If so, require the actual types to be consistent. */ for (j = 0; j < nargs; j++) { Oid decl_type = declared_arg_types[j]; Oid actual_type = actual_arg_types[j]; if (decl_type == ANYELEMENTOID || decl_type == ANYNONARRAYOID || decl_type == ANYENUMOID) { have_anyelement = true; if (decl_type == ANYNONARRAYOID) have_anynonarray = true; else if (decl_type == ANYENUMOID) have_anyenum = true; if (actual_type == UNKNOWNOID) continue; if (OidIsValid(elem_typeid) && actual_type != elem_typeid) return false; elem_typeid = actual_type; } else if (decl_type == ANYARRAYOID) { if (actual_type == UNKNOWNOID) continue; actual_type = getBaseType(actual_type); /* flatten domains */ if (OidIsValid(array_typeid) && actual_type != array_typeid) return false; array_typeid = actual_type; } else if (decl_type == ANYRANGEOID) { if (actual_type == UNKNOWNOID) continue; actual_type = getBaseType(actual_type); /* flatten domains */ if (OidIsValid(range_typeid) && actual_type != range_typeid) return false; range_typeid = actual_type; } } /* Get the element type based on the array type, if we have one */ if (OidIsValid(array_typeid)) { if (array_typeid == ANYARRAYOID) { /* Special case for ANYARRAY input: okay iff no ANYELEMENT */ if (have_anyelement) return false; return true; } array_typelem = get_element_type(array_typeid); if (!OidIsValid(array_typelem)) return false; /* should be an array, but isn't */ if (!OidIsValid(elem_typeid)) { /* * if we don't have an element type yet, use the one we just got */ elem_typeid = array_typelem; } else if (array_typelem != elem_typeid) { /* otherwise, they better match */ return false; } } /* Get the element type based on the range type, if we have one */ if (OidIsValid(range_typeid)) { range_typelem = get_range_subtype(range_typeid); if (!OidIsValid(range_typelem)) return false; /* should be a range, but isn't */ if (!OidIsValid(elem_typeid)) { /* * if we don't have an element type yet, use the one we just got */ elem_typeid = range_typelem; } else if (range_typelem != elem_typeid) { /* otherwise, they better match */ return false; } } if (have_anynonarray) { /* require the element type to not be an array or domain over array */ if (type_is_array_domain(elem_typeid)) return false; } if (have_anyenum) { /* require the element type to be an enum */ if (!type_is_enum(elem_typeid)) return false; } /* Looks valid */ return true; } /* * enforce_generic_type_consistency() * Make sure a polymorphic function is legally callable, and * deduce actual argument and result types. * * If any polymorphic pseudotype is used in a function's arguments or * return type, we make sure the actual data types are consistent with * each other. The argument consistency rules are shown above for * check_generic_type_consistency(). * * If we have UNKNOWN input (ie, an untyped literal) for any polymorphic * argument, we attempt to deduce the actual type it should have. If * successful, we alter that position of declared_arg_types[] so that * make_fn_arguments will coerce the literal to the right thing. * * Rules are applied to the function's return type (possibly altering it) * if it is declared as a polymorphic type: * * 1) If return type is ANYARRAY, and any argument is ANYARRAY, use the * argument's actual type as the function's return type. * 2) Similarly, if return type is ANYRANGE, and any argument is ANYRANGE, * use the argument's actual type as the function's return type. * 3) If return type is ANYARRAY, no argument is ANYARRAY, but any argument is * ANYELEMENT, use the actual type of the argument to determine the * function's return type, i.e. the element type's corresponding array * type. (Note: similar behavior does not exist for ANYRANGE, because it's * impossible to determine the range type from the subtype alone.) * 4) If return type is ANYARRAY, but no argument is ANYARRAY or ANYELEMENT, * generate an error. Similarly, if return type is ANYRANGE, but no * argument is ANYRANGE, generate an error. (These conditions are * prevented by CREATE FUNCTION and therefore are not expected here.) * 5) If return type is ANYELEMENT, and any argument is ANYELEMENT, use the * argument's actual type as the function's return type. * 6) If return type is ANYELEMENT, no argument is ANYELEMENT, but any argument * is ANYARRAY or ANYRANGE, use the actual type of the argument to determine * the function's return type, i.e. the array type's corresponding element * type or the range type's corresponding subtype (or both, in which case * they must match). * 7) If return type is ANYELEMENT, no argument is ANYELEMENT, ANYARRAY, or * ANYRANGE, generate an error. (This condition is prevented by CREATE * FUNCTION and therefore is not expected here.) * 8) ANYENUM is treated the same as ANYELEMENT except that if it is used * (alone or in combination with plain ANYELEMENT), we add the extra * condition that the ANYELEMENT type must be an enum. * 9) ANYNONARRAY is treated the same as ANYELEMENT except that if it is used, * we add the extra condition that the ANYELEMENT type must not be an array. * (This is a no-op if used in combination with ANYARRAY or ANYENUM, but * is an extra restriction if not.) * * Domains over arrays or ranges match ANYARRAY or ANYRANGE arguments, * respectively, and are immediately flattened to their base type. (In * particular, if the return type is also ANYARRAY or ANYRANGE, we'll set it * to the base type not the domain type.) * * When allow_poly is false, we are not expecting any of the actual_arg_types * to be polymorphic, and we should not return a polymorphic result type * either. When allow_poly is true, it is okay to have polymorphic "actual" * arg types, and we can return ANYARRAY, ANYRANGE, or ANYELEMENT as the * result. (This case is currently used only to check compatibility of an * aggregate's declaration with the underlying transfn.) * * A special case is that we could see ANYARRAY as an actual_arg_type even * when allow_poly is false (this is possible only because pg_statistic has * columns shown as anyarray in the catalogs). We allow this to match a * declared ANYARRAY argument, but only if there is no ANYELEMENT argument * or result (since we can't determine a specific element type to match to * ANYELEMENT). Note this means that functions taking ANYARRAY had better * behave sanely if applied to the pg_statistic columns; they can't just * assume that successive inputs are of the same actual element type. */ Oid enforce_generic_type_consistency(Oid *actual_arg_types, Oid *declared_arg_types, int nargs, Oid rettype, bool allow_poly) { int j; bool have_generics = false; bool have_unknowns = false; Oid elem_typeid = InvalidOid; Oid array_typeid = InvalidOid; Oid range_typeid = InvalidOid; Oid array_typelem; Oid range_typelem; bool have_anyelement = (rettype == ANYELEMENTOID || rettype == ANYNONARRAYOID || rettype == ANYENUMOID); bool have_anynonarray = (rettype == ANYNONARRAYOID); bool have_anyenum = (rettype == ANYENUMOID); /* * Loop through the arguments to see if we have any that are polymorphic. * If so, require the actual types to be consistent. */ for (j = 0; j < nargs; j++) { Oid decl_type = declared_arg_types[j]; Oid actual_type = actual_arg_types[j]; if (decl_type == ANYELEMENTOID || decl_type == ANYNONARRAYOID || decl_type == ANYENUMOID) { have_generics = have_anyelement = true; if (decl_type == ANYNONARRAYOID) have_anynonarray = true; else if (decl_type == ANYENUMOID) have_anyenum = true; if (actual_type == UNKNOWNOID) { have_unknowns = true; continue; } if (allow_poly && decl_type == actual_type) continue; /* no new information here */ if (OidIsValid(elem_typeid) && actual_type != elem_typeid) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("arguments declared \"anyelement\" are not all alike"), errdetail("%s versus %s", format_type_be(elem_typeid), format_type_be(actual_type)))); elem_typeid = actual_type; } else if (decl_type == ANYARRAYOID) { have_generics = true; if (actual_type == UNKNOWNOID) { have_unknowns = true; continue; } if (allow_poly && decl_type == actual_type) continue; /* no new information here */ actual_type = getBaseType(actual_type); /* flatten domains */ if (OidIsValid(array_typeid) && actual_type != array_typeid) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("arguments declared \"anyarray\" are not all alike"), errdetail("%s versus %s", format_type_be(array_typeid), format_type_be(actual_type)))); array_typeid = actual_type; } else if (decl_type == ANYRANGEOID) { have_generics = true; if (actual_type == UNKNOWNOID) { have_unknowns = true; continue; } if (allow_poly && decl_type == actual_type) continue; /* no new information here */ actual_type = getBaseType(actual_type); /* flatten domains */ if (OidIsValid(range_typeid) && actual_type != range_typeid) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("arguments declared \"anyrange\" are not all alike"), errdetail("%s versus %s", format_type_be(range_typeid), format_type_be(actual_type)))); range_typeid = actual_type; } } /* * Fast Track: if none of the arguments are polymorphic, return the * unmodified rettype. We assume it can't be polymorphic either. */ if (!have_generics) return rettype; /* Get the element type based on the array type, if we have one */ if (OidIsValid(array_typeid)) { if (array_typeid == ANYARRAYOID && !have_anyelement) { /* Special case for ANYARRAY input: okay iff no ANYELEMENT */ array_typelem = ANYELEMENTOID; } else { array_typelem = get_element_type(array_typeid); if (!OidIsValid(array_typelem)) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("argument declared %s is not an array but type %s", "anyarray", format_type_be(array_typeid)))); } if (!OidIsValid(elem_typeid)) { /* * if we don't have an element type yet, use the one we just got */ elem_typeid = array_typelem; } else if (array_typelem != elem_typeid) { /* otherwise, they better match */ ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("argument declared %s is not consistent with argument declared %s", "anyarray", "anyelement"), errdetail("%s versus %s", format_type_be(array_typeid), format_type_be(elem_typeid)))); } } /* Get the element type based on the range type, if we have one */ if (OidIsValid(range_typeid)) { if (range_typeid == ANYRANGEOID && !have_anyelement) { /* Special case for ANYRANGE input: okay iff no ANYELEMENT */ range_typelem = ANYELEMENTOID; } else { range_typelem = get_range_subtype(range_typeid); if (!OidIsValid(range_typelem)) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("argument declared %s is not a range type but type %s", "anyrange", format_type_be(range_typeid)))); } if (!OidIsValid(elem_typeid)) { /* * if we don't have an element type yet, use the one we just got */ elem_typeid = range_typelem; } else if (range_typelem != elem_typeid) { /* otherwise, they better match */ ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("argument declared %s is not consistent with argument declared %s", "anyrange", "anyelement"), errdetail("%s versus %s", format_type_be(range_typeid), format_type_be(elem_typeid)))); } } if (!OidIsValid(elem_typeid)) { if (allow_poly) { elem_typeid = ANYELEMENTOID; array_typeid = ANYARRAYOID; range_typeid = ANYRANGEOID; } else { /* Only way to get here is if all the generic args are UNKNOWN */ ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("could not determine polymorphic type because input has type %s", "unknown"))); } } if (have_anynonarray && elem_typeid != ANYELEMENTOID) { /* require the element type to not be an array or domain over array */ if (type_is_array_domain(elem_typeid)) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("type matched to anynonarray is an array type: %s", format_type_be(elem_typeid)))); } if (have_anyenum && elem_typeid != ANYELEMENTOID) { /* require the element type to be an enum */ if (!type_is_enum(elem_typeid)) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("type matched to anyenum is not an enum type: %s", format_type_be(elem_typeid)))); } /* * If we had any unknown inputs, re-scan to assign correct types */ if (have_unknowns) { for (j = 0; j < nargs; j++) { Oid decl_type = declared_arg_types[j]; Oid actual_type = actual_arg_types[j]; if (actual_type != UNKNOWNOID) continue; if (decl_type == ANYELEMENTOID || decl_type == ANYNONARRAYOID || decl_type == ANYENUMOID) declared_arg_types[j] = elem_typeid; else if (decl_type == ANYARRAYOID) { if (!OidIsValid(array_typeid)) { array_typeid = get_array_type(elem_typeid); if (!OidIsValid(array_typeid)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("could not find array type for data type %s", format_type_be(elem_typeid)))); } declared_arg_types[j] = array_typeid; } else if (decl_type == ANYRANGEOID) { if (!OidIsValid(range_typeid)) { ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("could not find range type for data type %s", format_type_be(elem_typeid)))); } declared_arg_types[j] = range_typeid; } } } /* if we return ANYARRAY use the appropriate argument type */ if (rettype == ANYARRAYOID) { if (!OidIsValid(array_typeid)) { array_typeid = get_array_type(elem_typeid); if (!OidIsValid(array_typeid)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("could not find array type for data type %s", format_type_be(elem_typeid)))); } return array_typeid; } /* if we return ANYRANGE use the appropriate argument type */ if (rettype == ANYRANGEOID) { if (!OidIsValid(range_typeid)) { ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("could not find range type for data type %s", format_type_be(elem_typeid)))); } return range_typeid; } /* if we return ANYELEMENT use the appropriate argument type */ if (rettype == ANYELEMENTOID || rettype == ANYNONARRAYOID || rettype == ANYENUMOID) return elem_typeid; /* we don't return a generic type; send back the original return type */ return rettype; } /* * resolve_generic_type() * Deduce an individual actual datatype on the assumption that * the rules for polymorphic types are being followed. * * declared_type is the declared datatype we want to resolve. * context_actual_type is the actual input datatype to some argument * that has declared datatype context_declared_type. * * If declared_type isn't polymorphic, we just return it. Otherwise, * context_declared_type must be polymorphic, and we deduce the correct * return type based on the relationship of the two polymorphic types. */ Oid resolve_generic_type(Oid declared_type, Oid context_actual_type, Oid context_declared_type) { if (declared_type == ANYARRAYOID) { if (context_declared_type == ANYARRAYOID) { /* * Use actual type, but it must be an array; or if it's a domain * over array, use the base array type. */ Oid context_base_type = getBaseType(context_actual_type); Oid array_typelem = get_element_type(context_base_type); if (!OidIsValid(array_typelem)) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("argument declared %s is not an array but type %s", "anyarray", format_type_be(context_base_type)))); return context_base_type; } else if (context_declared_type == ANYELEMENTOID || context_declared_type == ANYNONARRAYOID || context_declared_type == ANYENUMOID || context_declared_type == ANYRANGEOID) { /* Use the array type corresponding to actual type */ Oid array_typeid = get_array_type(context_actual_type); if (!OidIsValid(array_typeid)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("could not find array type for data type %s", format_type_be(context_actual_type)))); return array_typeid; } } else if (declared_type == ANYELEMENTOID || declared_type == ANYNONARRAYOID || declared_type == ANYENUMOID || declared_type == ANYRANGEOID) { if (context_declared_type == ANYARRAYOID) { /* Use the element type corresponding to actual type */ Oid context_base_type = getBaseType(context_actual_type); Oid array_typelem = get_element_type(context_base_type); if (!OidIsValid(array_typelem)) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("argument declared %s is not an array but type %s", "anyarray", format_type_be(context_base_type)))); return array_typelem; } else if (context_declared_type == ANYRANGEOID) { /* Use the element type corresponding to actual type */ Oid context_base_type = getBaseType(context_actual_type); Oid range_typelem = get_range_subtype(context_base_type); if (!OidIsValid(range_typelem)) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("argument declared %s is not a range type but type %s", "anyrange", format_type_be(context_base_type)))); return range_typelem; } else if (context_declared_type == ANYELEMENTOID || context_declared_type == ANYNONARRAYOID || context_declared_type == ANYENUMOID) { /* Use the actual type; it doesn't matter if array or not */ return context_actual_type; } } else { /* declared_type isn't polymorphic, so return it as-is */ return declared_type; } /* If we get here, declared_type is polymorphic and context isn't */ /* NB: this is a calling-code logic error, not a user error */ elog(ERROR, "could not determine polymorphic type because context isn't polymorphic"); return InvalidOid; /* keep compiler quiet */ } /* TypeCategory() * Assign a category to the specified type OID. * * NB: this must not return TYPCATEGORY_INVALID. */ TYPCATEGORY TypeCategory(Oid type) { char typcategory; bool typispreferred; get_type_category_preferred(type, &typcategory, &typispreferred); Assert(typcategory != TYPCATEGORY_INVALID); return (TYPCATEGORY) typcategory; } /* IsPreferredType() * Check if this type is a preferred type for the given category. * * If category is TYPCATEGORY_INVALID, then we'll return true for preferred * types of any category; otherwise, only for preferred types of that * category. */ bool IsPreferredType(TYPCATEGORY category, Oid type) { char typcategory; bool typispreferred; get_type_category_preferred(type, &typcategory, &typispreferred); if (category == typcategory || category == TYPCATEGORY_INVALID) return typispreferred; else return false; } /* IsBinaryCoercible() * Check if srctype is binary-coercible to targettype. * * This notion allows us to cheat and directly exchange values without * going through the trouble of calling a conversion function. Note that * in general, this should only be an implementation shortcut. Before 7.4, * this was also used as a heuristic for resolving overloaded functions and * operators, but that's basically a bad idea. * * As of 7.3, binary coercibility isn't hardwired into the code anymore. * We consider two types binary-coercible if there is an implicitly * invokable, no-function-needed pg_cast entry. Also, a domain is always * binary-coercible to its base type, though *not* vice versa (in the other * direction, one must apply domain constraint checks before accepting the * value as legitimate). We also need to special-case various polymorphic * types. * * This function replaces IsBinaryCompatible(), which was an inherently * symmetric test. Since the pg_cast entries aren't necessarily symmetric, * the order of the operands is now significant. */ bool IsBinaryCoercible(Oid srctype, Oid targettype) { HeapTuple tuple; Form_pg_cast castForm; bool result; /* Fast path if same type */ if (srctype == targettype) return true; /* Anything is coercible to ANY or ANYELEMENT */ if (targettype == ANYOID || targettype == ANYELEMENTOID) return true; /* If srctype is a domain, reduce to its base type */ if (OidIsValid(srctype)) srctype = getBaseType(srctype); /* Somewhat-fast path for domain -> base type case */ if (srctype == targettype) return true; /* Also accept any array type as coercible to ANYARRAY */ if (targettype == ANYARRAYOID) if (type_is_array(srctype)) return true; /* Also accept any non-array type as coercible to ANYNONARRAY */ if (targettype == ANYNONARRAYOID) if (!type_is_array(srctype)) return true; /* Also accept any enum type as coercible to ANYENUM */ if (targettype == ANYENUMOID) if (type_is_enum(srctype)) return true; /* Also accept any range type as coercible to ANYRANGE */ if (targettype == ANYRANGEOID) if (type_is_range(srctype)) return true; /* Also accept any composite type as coercible to RECORD */ if (targettype == RECORDOID) if (ISCOMPLEX(srctype)) return true; /* Also accept any composite array type as coercible to RECORD[] */ if (targettype == RECORDARRAYOID) if (is_complex_array(srctype)) return true; /* Else look in pg_cast */ tuple = SearchSysCache2(CASTSOURCETARGET, ObjectIdGetDatum(srctype), ObjectIdGetDatum(targettype)); if (!HeapTupleIsValid(tuple)) return false; /* no cast */ castForm = (Form_pg_cast) GETSTRUCT(tuple); result = (castForm->castmethod == COERCION_METHOD_BINARY && castForm->castcontext == COERCION_CODE_IMPLICIT); ReleaseSysCache(tuple); return result; } /* * find_coercion_pathway * Look for a coercion pathway between two types. * * Currently, this deals only with scalar-type cases; it does not consider * polymorphic types nor casts between composite types. (Perhaps fold * those in someday?) * * ccontext determines the set of available casts. * * The possible result codes are: * COERCION_PATH_NONE: failed to find any coercion pathway * *funcid is set to InvalidOid * COERCION_PATH_FUNC: apply the coercion function returned in *funcid * COERCION_PATH_RELABELTYPE: binary-compatible cast, no function needed * *funcid is set to InvalidOid * COERCION_PATH_ARRAYCOERCE: need an ArrayCoerceExpr node * *funcid is set to InvalidOid * COERCION_PATH_COERCEVIAIO: need a CoerceViaIO node * *funcid is set to InvalidOid * * Note: COERCION_PATH_RELABELTYPE does not necessarily mean that no work is * needed to do the coercion; if the target is a domain then we may need to * apply domain constraint checking. If you want to check for a zero-effort * conversion then use IsBinaryCoercible(). */ CoercionPathType find_coercion_pathway(Oid targetTypeId, Oid sourceTypeId, CoercionContext ccontext, Oid *funcid) { CoercionPathType result = COERCION_PATH_NONE; HeapTuple tuple; *funcid = InvalidOid; /* Perhaps the types are domains; if so, look at their base types */ if (OidIsValid(sourceTypeId)) sourceTypeId = getBaseType(sourceTypeId); if (OidIsValid(targetTypeId)) targetTypeId = getBaseType(targetTypeId); /* Domains are always coercible to and from their base type */ if (sourceTypeId == targetTypeId) return COERCION_PATH_RELABELTYPE; /* Look in pg_cast */ tuple = SearchSysCache2(CASTSOURCETARGET, ObjectIdGetDatum(sourceTypeId), ObjectIdGetDatum(targetTypeId)); if (HeapTupleIsValid(tuple)) { Form_pg_cast castForm = (Form_pg_cast) GETSTRUCT(tuple); CoercionContext castcontext; /* convert char value for castcontext to CoercionContext enum */ switch (castForm->castcontext) { case COERCION_CODE_IMPLICIT: castcontext = COERCION_IMPLICIT; break; case COERCION_CODE_ASSIGNMENT: castcontext = COERCION_ASSIGNMENT; break; case COERCION_CODE_EXPLICIT: castcontext = COERCION_EXPLICIT; break; default: elog(ERROR, "unrecognized castcontext: %d", (int) castForm->castcontext); castcontext = 0; /* keep compiler quiet */ break; } /* Rely on ordering of enum for correct behavior here */ if (ccontext >= castcontext) { switch (castForm->castmethod) { case COERCION_METHOD_FUNCTION: result = COERCION_PATH_FUNC; *funcid = castForm->castfunc; break; case COERCION_METHOD_INOUT: result = COERCION_PATH_COERCEVIAIO; break; case COERCION_METHOD_BINARY: result = COERCION_PATH_RELABELTYPE; break; default: elog(ERROR, "unrecognized castmethod: %d", (int) castForm->castmethod); break; } } ReleaseSysCache(tuple); } else { /* * If there's no pg_cast entry, perhaps we are dealing with a pair of * array types. If so, and if their element types have a conversion * pathway, report that we can coerce with an ArrayCoerceExpr. * * Hack: disallow coercions to oidvector and int2vector, which * otherwise tend to capture coercions that should go to "real" array * types. We want those types to be considered "real" arrays for many * purposes, but not this one. (Also, ArrayCoerceExpr isn't * guaranteed to produce an output that meets the restrictions of * these datatypes, such as being 1-dimensional.) */ if (targetTypeId != OIDVECTOROID && targetTypeId != INT2VECTOROID) { Oid targetElem; Oid sourceElem; if ((targetElem = get_element_type(targetTypeId)) != InvalidOid && (sourceElem = get_element_type(sourceTypeId)) != InvalidOid) { CoercionPathType elempathtype; Oid elemfuncid; elempathtype = find_coercion_pathway(targetElem, sourceElem, ccontext, &elemfuncid); if (elempathtype != COERCION_PATH_NONE) { result = COERCION_PATH_ARRAYCOERCE; } } } /* * If we still haven't found a possibility, consider automatic casting * using I/O functions. We allow assignment casts to string types and * explicit casts from string types to be handled this way. (The * CoerceViaIO mechanism is a lot more general than that, but this is * all we want to allow in the absence of a pg_cast entry.) It would * probably be better to insist on explicit casts in both directions, * but this is a compromise to preserve something of the pre-8.3 * behavior that many types had implicit (yipes!) casts to text. */ if (result == COERCION_PATH_NONE) { if (ccontext >= COERCION_ASSIGNMENT && TypeCategory(targetTypeId) == TYPCATEGORY_STRING) result = COERCION_PATH_COERCEVIAIO; else if (ccontext >= COERCION_EXPLICIT && TypeCategory(sourceTypeId) == TYPCATEGORY_STRING) result = COERCION_PATH_COERCEVIAIO; } } return result; } /* * find_typmod_coercion_function -- does the given type need length coercion? * * If the target type possesses a pg_cast function from itself to itself, * it must need length coercion. * * "bpchar" (ie, char(N)) and "numeric" are examples of such types. * * If the given type is a varlena array type, we do not look for a coercion * function associated directly with the array type, but instead look for * one associated with the element type. An ArrayCoerceExpr node must be * used to apply such a function. (Note: currently, it's pointless to * return the funcid in this case, because it'll just get looked up again * in the recursive construction of the ArrayCoerceExpr's elemexpr.) * * We use the same result enum as find_coercion_pathway, but the only possible * result codes are: * COERCION_PATH_NONE: no length coercion needed * COERCION_PATH_FUNC: apply the function returned in *funcid * COERCION_PATH_ARRAYCOERCE: apply the function using ArrayCoerceExpr */ CoercionPathType find_typmod_coercion_function(Oid typeId, Oid *funcid) { CoercionPathType result; Type targetType; Form_pg_type typeForm; HeapTuple tuple; *funcid = InvalidOid; result = COERCION_PATH_FUNC; targetType = typeidType(typeId); typeForm = (Form_pg_type) GETSTRUCT(targetType); /* Check for a varlena array type */ if (typeForm->typelem != InvalidOid && typeForm->typlen == -1) { /* Yes, switch our attention to the element type */ typeId = typeForm->typelem; result = COERCION_PATH_ARRAYCOERCE; } ReleaseSysCache(targetType); /* Look in pg_cast */ tuple = SearchSysCache2(CASTSOURCETARGET, ObjectIdGetDatum(typeId), ObjectIdGetDatum(typeId)); if (HeapTupleIsValid(tuple)) { Form_pg_cast castForm = (Form_pg_cast) GETSTRUCT(tuple); *funcid = castForm->castfunc; ReleaseSysCache(tuple); } if (!OidIsValid(*funcid)) result = COERCION_PATH_NONE; return result; } /* * is_complex_array * Is this type an array of composite? * * Note: this will not return true for record[]; check for RECORDARRAYOID * separately if needed. */ static bool is_complex_array(Oid typid) { Oid elemtype = get_element_type(typid); return (OidIsValid(elemtype) && ISCOMPLEX(elemtype)); } /* * Check whether reltypeId is the row type of a typed table of type * reloftypeId, or is a domain over such a row type. (This is conceptually * similar to the subtype relationship checked by typeInheritsFrom().) */ static bool typeIsOfTypedTable(Oid reltypeId, Oid reloftypeId) { Oid relid = typeOrDomainTypeRelid(reltypeId); bool result = false; if (relid) { HeapTuple tp; Form_pg_class reltup; tp = SearchSysCache1(RELOID, ObjectIdGetDatum(relid)); if (!HeapTupleIsValid(tp)) elog(ERROR, "cache lookup failed for relation %u", relid); reltup = (Form_pg_class) GETSTRUCT(tp); if (reltup->reloftype == reloftypeId) result = true; ReleaseSysCache(tp); } return result; }