/*------------------------------------------------------------------------- * * parse_coerce.c * handle type coercions/conversions for parser * * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * $PostgreSQL: pgsql/src/backend/parser/parse_coerce.c,v 2.177 2009/06/11 14:49:00 momjian Exp $ * *------------------------------------------------------------------------- */ #include "postgres.h" #include "catalog/pg_cast.h" #include "catalog/pg_inherits_fn.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_func.h" #include "parser/parse_relation.h" #include "parser/parse_type.h" #include "utils/builtins.h" #include "utils/fmgroids.h" #include "utils/lsyscache.h" #include "utils/syscache.h" #include "utils/typcache.h" static Node *coerce_type_typmod(Node *node, Oid targetTypeId, int32 targetTypMod, CoercionForm cformat, int location, bool isExplicit, bool hideInputCoercion); static void hide_coercion_node(Node *node); static Node *build_coercion_expression(Node *node, CoercionPathType pathtype, Oid funcId, Oid targetTypeId, int32 targetTypMod, CoercionForm cformat, int location, bool isExplicit); 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); /* * 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; if (!can_coerce_type(1, &exprtype, &targettype, ccontext)) return NULL; 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, cformat, location, (cformat != COERCE_IMPLICIT_CAST), (result != expr && !IsA(result, Const))); 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. */ 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 || (targetTypeId == ANYARRAYOID && inputTypeId != UNKNOWNOID) || (targetTypeId == ANYENUMOID && inputTypeId != UNKNOWNOID)) { /* * 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. * However an UNKNOWN value is definitely *not* an array, and so we * mustn't accept it for ANYARRAY. (Instead, we will call anyarray_in * below, which will produce an error.) Likewise, UNKNOWN input is no * good for ANYENUM. * * NB: we do NOT want a RelabelType here. */ 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 targetType; 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; targetType = typeidType(baseTypeId); newcon->consttype = baseTypeId; newcon->consttypmod = inputTypeMod; newcon->constlen = typeLen(targetType); newcon->constbyval = typeByVal(targetType); newcon->constisnull = con->constisnull; /* Use the leftmost of the constant's and coercion's locations */ if (location < 0) newcon->location = con->location; else if (con->location >= 0 && con->location < location) newcon->location = con->location; else newcon->location = 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(targetType, DatumGetCString(con->constvalue), inputTypeMod); else newcon->constvalue = stringTypeDatum(targetType, NULL, inputTypeMod); 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, cformat, location, false, false); ReleaseSysCache(targetType); return result; } if (inputTypeId == UNKNOWNOID && IsA(node, Param) && ((Param *) node)->paramkind == PARAM_EXTERN && pstate != NULL && pstate->p_variableparams) { /* * Input is a Param of previously undetermined type, and we want to * update our knowledge of the Param's type. Find the topmost * ParseState and update the state. */ Param *param = (Param *) node; int paramno = param->paramid; ParseState *toppstate; toppstate = pstate; while (toppstate->parentParseState != NULL) toppstate = toppstate->parentParseState; if (paramno <= 0 || /* shouldn't happen, but... */ paramno > toppstate->p_numparams) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_PARAMETER), errmsg("there is no parameter $%d", paramno), parser_errposition(pstate, param->location))); if (toppstate->p_paramtypes[paramno - 1] == UNKNOWNOID) { /* We've successfully resolved the type */ toppstate->p_paramtypes[paramno - 1] = targetTypeId; } else if (toppstate->p_paramtypes[paramno - 1] == targetTypeId) { /* We previously resolved the type, and it matches */ } else { /* Ooops */ ereport(ERROR, (errcode(ERRCODE_AMBIGUOUS_PARAMETER), errmsg("inconsistent types deduced for parameter $%d", paramno), errdetail("%s versus %s", format_type_be(toppstate->p_paramtypes[paramno - 1]), format_type_be(targetTypeId)), parser_errposition(pstate, param->location))); } param->paramtype = targetTypeId; /* * Note: it is tempting here to set the Param's paramtypmod to * targetTypeMod, but that is probably unwise because we have no * infrastructure that enforces that the value delivered for a Param * will match any particular typmod. Leaving it -1 ensures that a * run-time length check/coercion will occur if needed. */ param->paramtypmod = -1; /* Use the leftmost of the param's and coercion's locations */ if (location >= 0 && (param->location < 0 || location < param->location)) param->location = location; return (Node *) param; } 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, cformat, location, (cformat != COERCE_IMPLICIT_CAST)); /* * If domain, coerce to the domain type and relabel with domain * type ID. We can skip the internal length-coercion step if the * selected coercion function was a type-and-length coercion. */ if (targetTypeId != baseTypeId) result = coerce_to_domain(result, baseTypeId, baseTypeMod, targetTypeId, cformat, location, true, exprIsLengthCoercion(result, NULL)); } 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, cformat, location, false, 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, 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)) { /* * 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). */ ConvertRowtypeExpr *r = makeNode(ConvertRowtypeExpr); 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)) 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 * 'cformat': coercion format * 'location': coercion request location * 'hideInputCoercion': if true, hide the input coercion under this one. * 'lengthCoercionDone': if true, caller already accounted for length, * ie the input is already of baseTypMod as well as baseTypeId. * * 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, CoercionForm cformat, int location, bool hideInputCoercion, bool lengthCoercionDone) { 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. */ if (!lengthCoercionDone) { if (baseTypeMod >= 0) arg = coerce_type_typmod(arg, baseTypeId, baseTypeMod, COERCE_IMPLICIT_CAST, location, (cformat != COERCE_IMPLICIT_CAST), 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 */ 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. * * cformat determines the display properties of the generated node (if any), * while isExplicit may affect semantics. 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, CoercionForm cformat, int location, bool isExplicit, bool hideInputCoercion) { CoercionPathType pathtype; Oid funcId; /* * A negative typmod is assumed to mean that no coercion is wanted. Also, * skip coercion if already done. */ if (targetTypMod < 0 || targetTypMod == exprTypmod(node)) return node; pathtype = find_typmod_coercion_function(targetTypeId, &funcId); if (pathtype != COERCION_PATH_NONE) { /* Suppress display of nested coercion steps */ if (hideInputCoercion) hide_coercion_node(node); node = build_coercion_expression(node, pathtype, funcId, targetTypeId, targetTypMod, cformat, location, isExplicit); } 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, CoercionForm cformat, int location, bool isExplicit) { int nargs = 0; if (OidIsValid(funcId)) { HeapTuple tp; Form_pg_proc procstruct; tp = SearchSysCache(PROCOID, ObjectIdGetDatum(funcId), 0, 0, 0); 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->proisagg); Assert(!procstruct->proiswindow); 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, sizeof(int32), Int32GetDatum(targetTypMod), false, true); args = lappend(args, cons); } if (nargs == 3) { /* Pass it a boolean isExplicit parameter, too */ cons = makeConst(BOOLOID, -1, sizeof(bool), BoolGetDatum(isExplicit), false, true); args = lappend(args, cons); } fexpr = makeFuncExpr(funcId, targetTypeId, args, cformat); fexpr->location = location; return (Node *) fexpr; } else if (pathtype == COERCION_PATH_ARRAYCOERCE) { /* We need to build an ArrayCoerceExpr */ ArrayCoerceExpr *acoerce = makeNode(ArrayCoerceExpr); acoerce->arg = (Expr *) node; acoerce->elemfuncid = funcId; acoerce->resulttype = targetTypeId; /* * Label the output as having a particular typmod only if we are * really invoking a length-coercion function, ie one with more than * one argument. */ acoerce->resulttypmod = (nargs >= 2) ? targetTypMod : -1; acoerce->isExplicit = isExplicit; 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; 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; 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))); tupdesc = lookup_rowtype_tupdesc(targetTypeId, -1); newargs = NIL; ucolno = 1; arg = list_head(args); for (i = 0; i < tupdesc->natts; i++) { Node *expr; Node *cexpr; Oid exprtype; /* Fill in NULLs for dropped columns in rowtype */ if (tupdesc->attrs[i]->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)); 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, tupdesc->attrs[i]->atttypid, tupdesc->attrs[i]->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(tupdesc->attrs[i]->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 = targetTypeId; rowexpr->row_format = cformat; rowexpr->colnames = NIL; /* not needed for named target type */ rowexpr->location = location; 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 boolean, not type %s", constructName, 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() * 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) { Oid inputTypeId = exprType(node); if (inputTypeId != targetTypeId) { Node *newnode; newnode = coerce_to_target_type(pstate, node, inputTypeId, targetTypeId, -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 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; } /* * 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 ANYARRAY must have matching datatypes, * and must in fact be varlena arrays. * 2) All arguments declared ANYELEMENT must have matching datatypes. * 3) 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. * 4) 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. * 5) 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.) * * 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; 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; if (OidIsValid(array_typeid) && actual_type != array_typeid) return false; array_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; } } if (have_anynonarray) { /* require the element type to not be an array */ if (type_is_array(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) 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. * 3) If return type is ANYARRAY, no argument is ANYARRAY or ANYELEMENT, * generate an ERROR. This condition is prevented by CREATE FUNCTION * and is therefore not expected here. * 4) If return type is ANYELEMENT, and any argument is ANYELEMENT, use the * argument's actual type as the function's return type. * 5) If return type is ANYELEMENT, no argument is ANYELEMENT, but any * argument is ANYARRAY, use the actual type of the argument to determine * the function's return type, i.e. the array type's corresponding * element type. * 6) If return type is ANYELEMENT, no argument is ANYARRAY or ANYELEMENT, * generate an ERROR. This condition is prevented by CREATE FUNCTION * and is therefore not expected here. * 7) 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. * 8) 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.) * * 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 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 array_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 */ 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; } } /* * 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 = InvalidOid; } else { array_typelem = get_element_type(array_typeid); if (!OidIsValid(array_typelem)) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("argument declared \"anyarray\" is not an array but type %s", 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 \"anyarray\" is not consistent with argument declared \"anyelement\""), errdetail("%s versus %s", format_type_be(array_typeid), format_type_be(elem_typeid)))); } } else if (!OidIsValid(elem_typeid)) { if (allow_poly) { array_typeid = ANYARRAYOID; elem_typeid = ANYELEMENTOID; } 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 \"unknown\""))); } } if (have_anynonarray && elem_typeid != ANYELEMENTOID) { /* require the element type to not be an array */ if (type_is_array(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; } } } /* 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 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 */ Oid array_typelem = get_element_type(context_actual_type); if (!OidIsValid(array_typelem)) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("argument declared \"anyarray\" is not an array but type %s", format_type_be(context_actual_type)))); return context_actual_type; } else if (context_declared_type == ANYELEMENTOID || context_declared_type == ANYNONARRAYOID || context_declared_type == ANYENUMOID) { /* 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) { if (context_declared_type == ANYARRAYOID) { /* Use the element type corresponding to actual type */ Oid array_typelem = get_element_type(context_actual_type); if (!OidIsValid(array_typelem)) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("argument declared \"anyarray\" is not an array but type %s", format_type_be(context_actual_type)))); return array_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; /* 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 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 = SearchSysCache(CASTSOURCETARGET, ObjectIdGetDatum(srctype), ObjectIdGetDatum(targettype), 0, 0); if (!HeapTupleIsValid(tuple)) return false; /* no cast */ castForm = (Form_pg_cast) GETSTRUCT(tuple); result = (castForm->castfunc == InvalidOid && 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 the element cast function, or InvalidOid * if the array elements are binary-compatible * 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 = SearchSysCache(CASTSOURCETARGET, ObjectIdGetDatum(sourceTypeId), ObjectIdGetDatum(targetTypeId), 0, 0); 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 the element types have a suitable cast, * 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 && elempathtype != COERCION_PATH_ARRAYCOERCE) { *funcid = elemfuncid; if (elempathtype == COERCION_PATH_COERCEVIAIO) result = COERCION_PATH_COERCEVIAIO; else 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. * * 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 (and not a domain) */ if (typeForm->typelem != InvalidOid && typeForm->typlen == -1 && typeForm->typtype != TYPTYPE_DOMAIN) { /* Yes, switch our attention to the element type */ typeId = typeForm->typelem; result = COERCION_PATH_ARRAYCOERCE; } ReleaseSysCache(targetType); /* Look in pg_cast */ tuple = SearchSysCache(CASTSOURCETARGET, ObjectIdGetDatum(typeId), ObjectIdGetDatum(typeId), 0, 0); 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)); }