/*------------------------------------------------------------------------- * * parse_coerce.c * handle type coercions/conversions for parser * * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * $PostgreSQL: pgsql/src/backend/parser/parse_coerce.c,v 2.130 2005/05/30 01:20:49 tgl Exp $ * *------------------------------------------------------------------------- */ #include "postgres.h" #include "catalog/pg_cast.h" #include "catalog/pg_proc.h" #include "nodes/makefuncs.h" #include "nodes/params.h" #include "optimizer/clauses.h" #include "parser/parsetree.h" #include "parser/parse_coerce.h" #include "parser/parse_expr.h" #include "parser/parse_func.h" #include "parser/parse_relation.h" #include "parser/parse_type.h" #include "utils/builtins.h" #include "utils/fmgroids.h" #include "utils/lsyscache.h" #include "utils/syscache.h" #include "utils/typcache.h" static Node *coerce_type_typmod(Node *node, Oid targetTypeId, int32 targetTypMod, CoercionForm cformat, bool isExplicit, bool hideInputCoercion); static void hide_coercion_node(Node *node); static Node *build_coercion_expression(Node *node, Oid funcId, Oid targetTypeId, int32 targetTypMod, CoercionForm cformat, bool isExplicit); static Node *coerce_record_to_complex(ParseState *pstate, Node *node, Oid targetTypeId, CoercionContext ccontext, CoercionForm cformat); /* * 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 */ Node * coerce_to_target_type(ParseState *pstate, Node *expr, Oid exprtype, Oid targettype, int32 targettypmod, CoercionContext ccontext, CoercionForm cformat) { Node *result; if (!can_coerce_type(1, &exprtype, &targettype, ccontext)) return NULL; result = coerce_type(pstate, expr, exprtype, targettype, targettypmod, ccontext, cformat); /* * 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, (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) { Node *result; Oid funcId; if (targetTypeId == inputTypeId || node == NULL) { /* no conversion needed */ return node; } if (targetTypeId == ANYOID || targetTypeId == ANYARRAYOID || targetTypeId == ANYELEMENTOID) { /* assume can_coerce_type verified that implicit coercion is okay */ /* 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); Type targetType = typeidType(targetTypeId); char targetTyptype = typeTypType(targetType); newcon->consttype = targetTypeId; newcon->constlen = typeLen(targetType); newcon->constbyval = typeByVal(targetType); newcon->constisnull = con->constisnull; if (!con->constisnull) { /* * We assume here that UNKNOWN's internal representation is the * same as CSTRING */ char *val = DatumGetCString(con->constvalue); /* * We pass typmod -1 to the input routine, primarily 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. * * Note that we call stringTypeDatum using the domain's pg_type * row, if it's a domain. This works because the domain row * has the same typinput and typelem as the base type --- * ugly... */ newcon->constvalue = stringTypeDatum(targetType, val, -1); } result = (Node *) newcon; /* If target is a domain, apply constraints. */ if (targetTyptype == 'd') result = coerce_to_domain(result, InvalidOid, targetTypeId, cformat, false, false); ReleaseSysCache(targetType); return result; } if (inputTypeId == UNKNOWNOID && IsA(node, Param) && ((Param *) node)->paramkind == PARAM_NUM && 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))); 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)))); } param->paramtype = targetTypeId; return (Node *) param; } if (find_coercion_pathway(targetTypeId, inputTypeId, ccontext, &funcId)) { if (OidIsValid(funcId)) { /* * 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 = getBaseType(targetTypeId); int32 baseTypeMod; if (targetTypeId != baseTypeId) baseTypeMod = get_typtypmod(targetTypeId); else baseTypeMod = targetTypeMod; result = build_coercion_expression(node, funcId, baseTypeId, baseTypeMod, cformat, (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, targetTypeId, cformat, 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, targetTypeId, cformat, 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. */ result = (Node *) makeRelabelType((Expr *) result, targetTypeId, -1, cformat); } } 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); } if (targetTypeId == RECORDOID && ISCOMPLEX(inputTypeId)) { /* Coerce a specific complex 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; 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]; Oid funcId; /* no problem if same type */ if (inputTypeId == targetTypeId) continue; /* accept if target is ANY */ if (targetTypeId == ANYOID) continue; /* accept if target is ANYARRAY or ANYELEMENT, for now */ if (targetTypeId == ANYARRAYOID || targetTypeId == ANYELEMENTOID) { 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. */ if (find_coercion_pathway(targetTypeId, inputTypeId, ccontext, &funcId)) 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; /* * 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) * 'typeId': target type to coerce to * 'cformat': coercion format * 'hideInputCoercion': if true, hide the input coercion under this one. * 'lengthCoercionDone': if true, caller already accounted for length. * * If the target type isn't a domain, the given 'arg' is returned as-is. */ Node * coerce_to_domain(Node *arg, Oid baseTypeId, Oid typeId, CoercionForm cformat, bool hideInputCoercion, bool lengthCoercionDone) { CoerceToDomain *result; /* Get the base type if it hasn't been supplied */ if (baseTypeId == InvalidOid) baseTypeId = getBaseType(typeId); /* 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) { int32 typmod = get_typtypmod(typeId); if (typmod >= 0) arg = coerce_type_typmod(arg, baseTypeId, typmod, COERCE_IMPLICIT_CAST, (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; 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, bool isExplicit, bool hideInputCoercion) { 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; funcId = find_typmod_coercion_function(targetTypeId); if (OidIsValid(funcId)) { /* Suppress display of nested coercion steps */ if (hideInputCoercion) hide_coercion_node(node); node = build_coercion_expression(node, funcId, targetTypeId, targetTypMod, cformat, 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, 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 a function-call expression for applying a pg_cast entry. * * This is used for both type-coercion and length-coercion functions, * since there is no difference in terms of the calling convention. */ static Node * build_coercion_expression(Node *node, Oid funcId, Oid targetTypeId, int32 targetTypMod, CoercionForm cformat, bool isExplicit) { HeapTuple tp; Form_pg_proc procstruct; int nargs; List *args; Const *cons; 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); /* * Asserts essentially check that function is a legal coercion * function. We can't make the seemingly obvious tests on prorettype * and proargtypes[0], because of various binary-compatibility cases. */ /* Assert(targetTypeId == procstruct->prorettype); */ Assert(!procstruct->proretset); Assert(!procstruct->proisagg); 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); args = list_make1(node); if (nargs >= 2) { /* Pass target typmod as an int4 constant */ cons = makeConst(INT4OID, sizeof(int32), Int32GetDatum(targetTypMod), false, true); args = lappend(args, cons); } if (nargs == 3) { /* Pass it a boolean isExplicit parameter, too */ cons = makeConst(BOOLOID, sizeof(bool), BoolGetDatum(isExplicit), false, true); args = lappend(args, cons); } return (Node *) makeFuncExpr(funcId, targetTypeId, args, cformat); } /* * 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) { 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; List *rtable; rtable = GetLevelNRangeTable(pstate, sublevels_up); expandRTE(rtable, rtindex, sublevels_up, 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)))); tupdesc = lookup_rowtype_tupdesc(targetTypeId, -1); newargs = NIL; ucolno = 1; arg = list_head(args); for (i = 0; i < tupdesc->natts; i++) { Node *expr; 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)); 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."))); expr = (Node *) lfirst(arg); exprtype = exprType(expr); expr = coerce_to_target_type(pstate, expr, exprtype, tupdesc->attrs[i]->atttypid, tupdesc->attrs[i]->atttypmod, ccontext, COERCE_IMPLICIT_CAST); if (expr == 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))); newargs = lappend(newargs, expr); 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."))); rowexpr = makeNode(RowExpr); rowexpr->args = newargs; rowexpr->row_typeid = targetTypeId; rowexpr->row_format = cformat; 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 = coerce_to_target_type(pstate, node, inputTypeId, BOOLOID, -1, COERCION_ASSIGNMENT, COERCE_IMPLICIT_CAST); if (node == 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)))); } 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))); return node; } /* coerce_to_integer() * Coerce an argument of a construct that requires integer input * (LIMIT, OFFSET, 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_integer(ParseState *pstate, Node *node, const char *constructName) { Oid inputTypeId = exprType(node); if (inputTypeId != INT4OID) { node = coerce_to_target_type(pstate, node, inputTypeId, INT4OID, -1, COERCION_ASSIGNMENT, COERCE_IMPLICIT_CAST); if (node == 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 integer, not type %s", constructName, format_type_be(inputTypeId)))); } 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))); return node; } /* select_common_type() * Determine the common supertype of a list of input expression types. * This is used for determining the output type of CASE and UNION * constructs. * * typeids is a nonempty list of type OIDs. 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. */ Oid select_common_type(List *typeids, const char *context) { Oid ptype; CATEGORY pcategory; ListCell *type_item; Assert(typeids != NIL); ptype = getBaseType(linitial_oid(typeids)); pcategory = TypeCategory(ptype); for_each_cell(type_item, lnext(list_head(typeids))) { Oid ntype = getBaseType(lfirst_oid(type_item)); /* move on to next one if no new information... */ if ((ntype != InvalidOid) && (ntype != UNKNOWNOID) && (ntype != ptype)) { if ((ptype == InvalidOid) || ptype == UNKNOWNOID) { /* so far, only nulls so take anything... */ ptype = ntype; pcategory = TypeCategory(ptype); } else if (TypeCategory(ntype) != pcategory) { /* * both types in different categories? then not much * hope... */ 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)))); } else if (!IsPreferredType(pcategory, ptype) && 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. */ ptype = ntype; pcategory = TypeCategory(ptype); } } } /* * 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; 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); 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)))); 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. * * If we have UNKNOWN input (ie, an untyped literal) for any ANYELEMENT * or ANYARRAY 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; /* * Loop through the arguments to see if we have any that are ANYARRAY * or ANYELEMENT. If so, require the actual types to be * self-consistent */ for (j = 0; j < nargs; j++) { Oid actual_type = actual_arg_types[j]; if (declared_arg_types[j] == ANYELEMENTOID) { have_anyelement = true; if (actual_type == UNKNOWNOID) continue; if (OidIsValid(elem_typeid) && actual_type != elem_typeid) return false; elem_typeid = actual_type; } else if (declared_arg_types[j] == 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; } } /* Looks valid */ return true; } /* * enforce_generic_type_consistency() * Make sure a polymorphic function is legally callable, and * deduce actual argument and result types. * * If ANYARRAY or ANYELEMENT is used for 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 ANYELEMENT * or ANYARRAY 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 ANYARRAY or ANYELEMENT: * * 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. */ Oid enforce_generic_type_consistency(Oid *actual_arg_types, Oid *declared_arg_types, int nargs, Oid rettype) { 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); /* * Loop through the arguments to see if we have any that are ANYARRAY * or ANYELEMENT. If so, require the actual types to be * self-consistent */ for (j = 0; j < nargs; j++) { Oid actual_type = actual_arg_types[j]; if (declared_arg_types[j] == ANYELEMENTOID) { have_generics = have_anyelement = true; if (actual_type == UNKNOWNOID) { have_unknowns = true; continue; } 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 (declared_arg_types[j] == ANYARRAYOID) { have_generics = true; if (actual_type == UNKNOWNOID) { have_unknowns = true; continue; } 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 ANYARRAY or ANYELEMENT, * return the unmodified rettype. */ 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)) { /* Only way to get here is if all the generic args are UNKNOWN */ ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("could not determine anyarray/anyelement type because input has type \"unknown\""))); } /* * If we had any unknown inputs, re-scan to assign correct types */ if (have_unknowns) { for (j = 0; j < nargs; j++) { Oid actual_type = actual_arg_types[j]; if (actual_type != UNKNOWNOID) continue; if (declared_arg_types[j] == ANYELEMENTOID) declared_arg_types[j] = elem_typeid; else if (declared_arg_types[j] == 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 ANYARRAYOID 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 ANYELEMENTOID use the appropriate argument type */ if (rettype == ANYELEMENTOID) 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 ANYARRAY/ANYELEMENT 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) { /* 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) { 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) { /* 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 ANYARRAY/ANYELEMENT 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 INVALID_TYPE. * * XXX This should be moved to system catalog lookups * to allow for better type extensibility. * - thomas 2001-09-30 */ CATEGORY TypeCategory(Oid inType) { CATEGORY result; switch (inType) { case (BOOLOID): result = BOOLEAN_TYPE; break; case (CHAROID): case (NAMEOID): case (BPCHAROID): case (VARCHAROID): case (TEXTOID): result = STRING_TYPE; break; case (BITOID): case (VARBITOID): result = BITSTRING_TYPE; break; case (OIDOID): case (REGPROCOID): case (REGPROCEDUREOID): case (REGOPEROID): case (REGOPERATOROID): case (REGCLASSOID): case (REGTYPEOID): case (INT2OID): case (INT4OID): case (INT8OID): case (FLOAT4OID): case (FLOAT8OID): case (NUMERICOID): case (CASHOID): result = NUMERIC_TYPE; break; case (DATEOID): case (TIMEOID): case (TIMETZOID): case (ABSTIMEOID): case (TIMESTAMPOID): case (TIMESTAMPTZOID): result = DATETIME_TYPE; break; case (RELTIMEOID): case (TINTERVALOID): case (INTERVALOID): result = TIMESPAN_TYPE; break; case (POINTOID): case (LSEGOID): case (PATHOID): case (BOXOID): case (POLYGONOID): case (LINEOID): case (CIRCLEOID): result = GEOMETRIC_TYPE; break; case (INETOID): case (CIDROID): result = NETWORK_TYPE; break; case (UNKNOWNOID): case (InvalidOid): result = UNKNOWN_TYPE; break; case (RECORDOID): case (CSTRINGOID): case (ANYOID): case (ANYARRAYOID): case (VOIDOID): case (TRIGGEROID): case (LANGUAGE_HANDLEROID): case (INTERNALOID): case (OPAQUEOID): case (ANYELEMENTOID): result = GENERIC_TYPE; break; default: result = USER_TYPE; break; } return result; } /* TypeCategory() */ /* IsPreferredType() * Check if this type is a preferred type for the given category. * * If category is INVALID_TYPE, then we'll return TRUE for preferred types * of any category; otherwise, only for preferred types of that category. * * XXX This should be moved to system catalog lookups * to allow for better type extensibility. * - thomas 2001-09-30 */ bool IsPreferredType(CATEGORY category, Oid type) { Oid preftype; if (category == INVALID_TYPE) category = TypeCategory(type); else if (category != TypeCategory(type)) return false; /* * This switch should agree with TypeCategory(), above. Note that at * this point, category certainly matches the type. */ switch (category) { case (UNKNOWN_TYPE): case (GENERIC_TYPE): preftype = UNKNOWNOID; break; case (BOOLEAN_TYPE): preftype = BOOLOID; break; case (STRING_TYPE): preftype = TEXTOID; break; case (BITSTRING_TYPE): preftype = VARBITOID; break; case (NUMERIC_TYPE): if (type == OIDOID || type == REGPROCOID || type == REGPROCEDUREOID || type == REGOPEROID || type == REGOPERATOROID || type == REGCLASSOID || type == REGTYPEOID) preftype = OIDOID; else preftype = FLOAT8OID; break; case (DATETIME_TYPE): if (type == DATEOID) preftype = TIMESTAMPOID; else preftype = TIMESTAMPTZOID; break; case (TIMESPAN_TYPE): preftype = INTERVALOID; break; case (GEOMETRIC_TYPE): preftype = type; break; case (NETWORK_TYPE): preftype = INETOID; break; case (USER_TYPE): preftype = type; break; default: elog(ERROR, "unrecognized type category: %d", (int) category); preftype = UNKNOWNOID; break; } return (type == preftype); } /* IsPreferredType() */ /* 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 the polymorphic * ANYARRAY type. * * 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 (get_element_type(srctype) != InvalidOid) 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. * * ccontext determines the set of available casts. * * If we find a suitable entry in pg_cast, return TRUE, and set *funcid * to the castfunc value, which may be InvalidOid for a binary-compatible * coercion. * * NOTE: *funcid == InvalidOid 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(). */ bool find_coercion_pathway(Oid targetTypeId, Oid sourceTypeId, CoercionContext ccontext, Oid *funcid) { bool result = false; 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 true; /* 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) { *funcid = castForm->castfunc; result = true; } 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, use array_type_coerce() or * array_type_length_coerce(). * * 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, array_type_coerce isn't * guaranteed to produce an output that meets the restrictions of * these datatypes, such as being 1-dimensional.) */ Oid targetElemType; Oid sourceElemType; Oid elemfuncid; if (targetTypeId == OIDVECTOROID || targetTypeId == INT2VECTOROID) return false; if ((targetElemType = get_element_type(targetTypeId)) != InvalidOid && (sourceElemType = get_element_type(sourceTypeId)) != InvalidOid) { if (find_coercion_pathway(targetElemType, sourceElemType, ccontext, &elemfuncid)) { if (!OidIsValid(elemfuncid)) { /* binary-compatible element type conversion */ *funcid = F_ARRAY_TYPE_COERCE; } else { /* does the function take a typmod arg? */ if (get_func_nargs(elemfuncid) > 1) *funcid = F_ARRAY_TYPE_LENGTH_COERCE; else *funcid = F_ARRAY_TYPE_COERCE; } result = true; } } } 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. If one exists, we report * array_length_coerce() as the coercion function to use. */ Oid find_typmod_coercion_function(Oid typeId) { Oid funcid = InvalidOid; bool isArray = false; Type targetType; Form_pg_type typeForm; HeapTuple tuple; 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 != 'd') { /* Yes, switch our attention to the element type */ typeId = typeForm->typelem; isArray = true; } 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); } /* * Now, if we did find a coercion function for an array element type, * report array_length_coerce() as the function to use. */ if (isArray && OidIsValid(funcid)) funcid = F_ARRAY_LENGTH_COERCE; return funcid; }