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postgresql/src/backend/parser/parse_coerce.c

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/*-------------------------------------------------------------------------
*
* 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));
}
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