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Fix handling of pg_type.typdefault per bug report from Dave Blasby.

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If there's anyone out there who's actually using datatype-defined
default values, this will be an incompatible change in behavior ...
but the old behavior was so broken that I doubt anyone was using it.
This commit is contained in:
Tom Lane
2001-09-06 02:07:42 +00:00
parent f2b604ecf4
commit 6c91eef7b7
11 changed files with 210 additions and 147 deletions
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92
src/backend/utils/cache/lsyscache.c vendored
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@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/cache/lsyscache.c,v 1.57 2001/08/21 16:36:05 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/cache/lsyscache.c,v 1.58 2001/09/06 02:07:42 tgl Exp $
*
* NOTES
* Eventually, the index information should go through here, too.
@ -750,23 +750,20 @@ get_typstorage(Oid typid)
/*
* get_typdefault
*
* Given a type OID, return the typdefault field associated with that
* type, or Datum(NULL) if there is no typdefault. (This implies
* that pass-by-value types can't have a default value that has
* a representation of zero. Not worth fixing now.)
* The result points to palloc'd storage for non-pass-by-value types.
* Given a type OID, return the type's default value, if any.
* Returns FALSE if there is no default (effectively, default is NULL).
* The result points to palloc'd storage for pass-by-reference types.
*/
Datum
get_typdefault(Oid typid)
bool
get_typdefault(Oid typid, Datum *defaultValue)
{
HeapTuple typeTuple;
Form_pg_type type;
struct varlena *typDefault;
Oid typinput,
typelem;
Datum textDefaultVal;
bool isNull;
int32 dataSize;
int32 typLen;
bool typByVal;
Datum returnValue;
char *strDefaultVal;
typeTuple = SearchSysCache(TYPEOID,
ObjectIdGetDatum(typid),
@ -777,66 +774,39 @@ get_typdefault(Oid typid)
type = (Form_pg_type) GETSTRUCT(typeTuple);
typinput = type->typinput;
typelem = type->typelem;
/*
* First, see if there is a non-null typdefault field (usually there
* isn't)
* typdefault is potentially null, so don't try to access it as a struct
* field. Must do it the hard way with SysCacheGetAttr.
*/
typDefault = (struct varlena *)
DatumGetPointer(SysCacheGetAttr(TYPEOID,
typeTuple,
Anum_pg_type_typdefault,
&isNull));
textDefaultVal = SysCacheGetAttr(TYPEOID,
typeTuple,
Anum_pg_type_typdefault,
&isNull);
if (isNull)
{
ReleaseSysCache(typeTuple);
return PointerGetDatum(NULL);
*defaultValue = (Datum) 0;
return false;
}
/*
* Otherwise, extract/copy the value.
*/
dataSize = VARSIZE(typDefault) - VARHDRSZ;
typLen = type->typlen;
typByVal = type->typbyval;
/* Convert text datum to C string */
strDefaultVal = DatumGetCString(DirectFunctionCall1(textout,
textDefaultVal));
if (typByVal)
{
if (dataSize == typLen)
returnValue = fetch_att(VARDATA(typDefault), typByVal, typLen);
else
returnValue = PointerGetDatum(NULL);
}
else if (typLen < 0)
{
/* variable-size type */
if (dataSize < 0)
returnValue = PointerGetDatum(NULL);
else
{
returnValue = PointerGetDatum(palloc(VARSIZE(typDefault)));
memcpy((char *) DatumGetPointer(returnValue),
(char *) typDefault,
(int) VARSIZE(typDefault));
}
}
else
{
/* fixed-size pass-by-ref type */
if (dataSize != typLen)
returnValue = PointerGetDatum(NULL);
else
{
returnValue = PointerGetDatum(palloc(dataSize));
memcpy((char *) DatumGetPointer(returnValue),
VARDATA(typDefault),
(int) dataSize);
}
}
/* Convert C string to a value of the given type */
*defaultValue = OidFunctionCall3(typinput,
CStringGetDatum(strDefaultVal),
ObjectIdGetDatum(typelem),
Int32GetDatum(-1));
pfree(strDefaultVal);
ReleaseSysCache(typeTuple);
return returnValue;
return true;
}
/*