/*
* inv_create -- create a new large object
*
* Arguments:
* lobjId - OID to use for new large object, or InvalidOid to pick one
*
* Returns:
* OID of new object
*
* If lobjId is not InvalidOid, then an error occurs if the OID is already
* in use.
*/
Oid
inv_create(Oid lobjId)
{
Oid lobjId_new;
/*
* Create a new largeobject with empty data pages
*/
lobjId_new = LargeObjectCreate(lobjId);
/*
* dependency on the owner of largeobject
*
* The reason why we use LargeObjectRelationId instead of
* LargeObjectMetadataRelationId here is to provide backward compatibility
* to the applications which utilize a knowledge about internal layout of
* system catalogs. OID of pg_largeobject_metadata and loid of
* pg_largeobject are same value, so there are no actual differences here.
*/
recordDependencyOnOwner(LargeObjectRelationId,
lobjId_new, GetUserId());
/* Post creation hook for new large object */
InvokeObjectAccessHook(OAT_POST_CREATE,
LargeObjectRelationId, lobjId_new, 0);
/*
* Advance command counter to make new tuple visible to later operations.
*/
CommandCounterIncrement();
return lobjId_new;
}
/*
* inv_create -- create a new large object
*
* Arguments:
* lobjId - OID to use for new large object, or InvalidOid to pick one
*
* Returns:
* OID of new object
*
* If lobjId is not InvalidOid, then an error occurs if the OID is already
* in use.
*/
Oid
inv_create(Oid lobjId)
{
/*
* Allocate an OID to be the LO's identifier, unless we were told what to
* use. We can use the index on pg_largeobject for checking OID
* uniqueness, even though it has additional columns besides OID.
*/
if (!OidIsValid(lobjId))
{
open_lo_relation();
lobjId = GetNewOidWithIndex(lo_heap_r, lo_index_r);
}
/*
* Create the LO by writing an empty first page for it in pg_largeobject
* (will fail if duplicate)
*/
LargeObjectCreate(lobjId);
/*
* Advance command counter to make new tuple visible to later operations.
*/
CommandCounterIncrement();
return lobjId;
}
/*
* inv_create -- create a new large object.
*
* Arguments:
* flags
*
* Returns:
* large object descriptor, appropriately filled in.
*/
LargeObjectDesc *
inv_create(int flags)
{
Oid file_oid;
LargeObjectDesc *retval;
/*
* Allocate an OID to be the LO's identifier.
*/
file_oid = newoid();
/* Check for duplicate (shouldn't happen) */
if (LargeObjectExists(file_oid))
elog(ERROR, "large object %u already exists", file_oid);
/*
* Create the LO by writing an empty first page for it in
* pg_largeobject
*/
LargeObjectCreate(file_oid);
/*
* Advance command counter so that new tuple will be seen by later
* large-object operations in this transaction.
*/
CommandCounterIncrement();
/*
* Prepare LargeObjectDesc data structure for accessing LO
*/
retval = (LargeObjectDesc *) palloc(sizeof(LargeObjectDesc));
retval->id = file_oid;
retval->subid = GetCurrentSubTransactionId();
retval->offset = 0;
if (flags & INV_WRITE)
retval->flags = IFS_WRLOCK | IFS_RDLOCK;
else if (flags & INV_READ)
retval->flags = IFS_RDLOCK;
else
elog(ERROR, "invalid flags: %d", flags);
return retval;
}
