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/*-------------------------------------------------------------------------
*
* catalog.c
*
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/catalog/catalog.c,v 1.27 2000/01/15 02:59:28 petere Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/transam.h"
#include "catalog/catalog.h"
#include "catalog/catname.h"
#include "catalog/pg_type.h"
#include "miscadmin.h"
#include "utils/syscache.h"
/*
* relpath - path to the relation
* Perhaps this should be in-line code in relopen().
*/
char *
relpath(char *relname)
{
char *path;
size_t bufsize = 0;
if (IsSharedSystemRelationName(relname))
{
bufsize = strlen(DataDir) + sizeof(NameData) + 2;
path = (char *) palloc(bufsize);
snprintf(path, bufsize, "%s/%s", DataDir, relname);
return path;
}
return relname;
}
/*
* IsSystemRelationName
* True iff name is the name of a system catalog relation.
*
* We now make a new requirement where system catalog relns must begin
* with pg_ while user relns are forbidden to do so. Make the test
* trivial and instantaneous.
*
* XXX this is way bogus. -- pma
*/
bool
IsSystemRelationName(char *relname)
{
if (relname[0] && relname[1] && relname[2])
return (relname[0] == 'p' &&
relname[1] == 'g' &&
relname[2] == '_');
else
return FALSE;
}
/*
* IsSharedSystemRelationName
* True iff name is the name of a shared system catalog relation.
*/
bool
IsSharedSystemRelationName(char *relname)
{
int i;
/*
* Quick out: if it's not a system relation, it can't be a shared
* system relation.
*/
if (!IsSystemRelationName(relname))
return FALSE;
i = 0;
while (SharedSystemRelationNames[i] != NULL)
{
if (strcmp(SharedSystemRelationNames[i], relname) == 0)
return TRUE;
i++;
}
return FALSE;
}
/*
* newoid - returns a unique identifier across all catalogs.
*
* Object Id allocation is now done by GetNewObjectID in
* access/transam/varsup.c. oids are now allocated correctly.
*
* old comments:
* This needs to change soon, it fails if there are too many more
* than one call per second when postgres restarts after it dies.
*
* The distribution of OID's should be done by the POSTMASTER.
* Also there needs to be a facility to preallocate OID's. Ie.,
* for a block of OID's to be declared as invalid ones to allow
* user programs to use them for temporary object identifiers.
*/
Oid
newoid()
{
Oid lastoid;
GetNewObjectId(&lastoid);
if (!OidIsValid(lastoid))
elog(ERROR, "newoid: GetNewObjectId returns invalid oid");
return lastoid;
}
/*
* fillatt - fills the ATTRIBUTE relation fields from the TYP
*
* Expects that the atttypid domain is set for each att[].
* Returns with the attnum, and attlen domains set.
* attnum, attproc, atttyparg, ... should be set by the user.
*
* In the future, attnum may not be set?!? or may be passed as an arg?!?
*
* Current implementation is very inefficient--should cashe the
* information if this is at all possible.
*
* Check to see if this is really needed, and especially in the case
* of index tuples.
*/
void
fillatt(TupleDesc tupleDesc)
{
Form_pg_attribute *attributeP;
Form_pg_type typp;
HeapTuple tuple;
int i;
int natts = tupleDesc->natts;
Form_pg_attribute *att = tupleDesc->attrs;
if (natts < 0 || natts > MaxHeapAttributeNumber)
elog(ERROR, "fillatt: %d attributes is too large", natts);
if (natts == 0)
{
elog(DEBUG, "fillatt: called with natts == 0");
return;
}
attributeP = &att[0];
for (i = 0; i < natts;)
{
tuple = SearchSysCacheTuple(TYPEOID,
ObjectIdGetDatum((*attributeP)->atttypid),
0, 0, 0);
if (!HeapTupleIsValid(tuple))
{
elog(ERROR, "fillatt: unknown atttypid %d",
(*attributeP)->atttypid);
}
else
{
(*attributeP)->attnum = (int16) ++i;
/*
* Check if the attr is a set before messing with the length
* and byval, since those were already set in
* TupleDescInitEntry. In fact, this seems redundant here,
* but who knows what I'll break if I take it out...
*/
if (!(*attributeP)->attisset)
{
typp = (Form_pg_type) GETSTRUCT(tuple); /* XXX */
(*attributeP)->attlen = typp->typlen;
(*attributeP)->attbyval = typp->typbyval;
}
}
attributeP += 1;
}
}