pg_largeobject.c File Reference

#include "postgres.h"
#include "access/table.h"
#include "catalog/catalog.h"
#include "catalog/indexing.h"
#include "catalog/pg_largeobject.h"
#include "catalog/pg_largeobject_metadata.h"
#include "miscadmin.h"
#include "utils/fmgroids.h"
#include "utils/rel.h"

Include dependency graph for pg_largeobject.c:

Go to the source code of this file.

Functions
Oid	LargeObjectCreate (Oid loid)
void	LargeObjectDrop (Oid loid)
bool	LargeObjectExists (Oid loid)
bool	LargeObjectExistsWithSnapshot (Oid loid, Snapshot snapshot)

Function Documentation

LargeObjectCreate()

Oid LargeObjectCreate

(

Oid

loid

)

Definition at line 35 of file pg_largeobject.c.

{
    Relation    pg_lo_meta;
    HeapTuple   ntup;
    Oid         loid_new;
    Datum       values[Natts_pg_largeobject_metadata];
    bool        nulls[Natts_pg_largeobject_metadata];
 
    pg_lo_meta = table_open(LargeObjectMetadataRelationId,
                            RowExclusiveLock);
 
    /*
     * Insert metadata of the largeobject
     */
    memset(values, 0, sizeof(values));
    memset(nulls, false, sizeof(nulls));
 
    if (OidIsValid(loid))
        loid_new = loid;
    else
        loid_new = GetNewOidWithIndex(pg_lo_meta,
                                      LargeObjectMetadataOidIndexId,
                                      Anum_pg_largeobject_metadata_oid);
 
    values[Anum_pg_largeobject_metadata_oid - 1] = ObjectIdGetDatum(loid_new);
    values[Anum_pg_largeobject_metadata_lomowner - 1]
        = ObjectIdGetDatum(GetUserId());
    nulls[Anum_pg_largeobject_metadata_lomacl - 1] = true;
 
    ntup = heap_form_tuple(RelationGetDescr(pg_lo_meta),
                           values, nulls);
 
    CatalogTupleInsert(pg_lo_meta, ntup);
 
    heap_freetuple(ntup);
 
    table_close(pg_lo_meta, RowExclusiveLock);
 
    return loid_new;
}

References CatalogTupleInsert(), GetNewOidWithIndex(), GetUserId(), heap_form_tuple(), heap_freetuple(), ObjectIdGetDatum(), OidIsValid, RelationGetDescr, RowExclusiveLock, table_close(), table_open(), and values.

Referenced by inv_create().

LargeObjectDrop()

void LargeObjectDrop

(

Oid

loid

)

Definition at line 81 of file pg_largeobject.c.

{
    Relation    pg_lo_meta;
    Relation    pg_largeobject;
    ScanKeyData skey[1];
    SysScanDesc scan;
    HeapTuple   tuple;
 
    pg_lo_meta = table_open(LargeObjectMetadataRelationId,
                            RowExclusiveLock);
 
    pg_largeobject = table_open(LargeObjectRelationId,
                                RowExclusiveLock);
 
    /*
     * Delete an entry from pg_largeobject_metadata
     */
    ScanKeyInit(&skey[0],
                Anum_pg_largeobject_metadata_oid,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(loid));
 
    scan = systable_beginscan(pg_lo_meta,
                              LargeObjectMetadataOidIndexId, true,
                              NULL, 1, skey);
 
    tuple = systable_getnext(scan);
    if (!HeapTupleIsValid(tuple))
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_OBJECT),
                 errmsg("large object %u does not exist", loid)));
 
    CatalogTupleDelete(pg_lo_meta, &tuple->t_self);
 
    systable_endscan(scan);
 
    /*
     * Delete all the associated entries from pg_largeobject
     */
    ScanKeyInit(&skey[0],
                Anum_pg_largeobject_loid,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(loid));
 
    scan = systable_beginscan(pg_largeobject,
                              LargeObjectLOidPNIndexId, true,
                              NULL, 1, skey);
    while (HeapTupleIsValid(tuple = systable_getnext(scan)))
    {
        CatalogTupleDelete(pg_largeobject, &tuple->t_self);
    }
 
    systable_endscan(scan);
 
    table_close(pg_largeobject, RowExclusiveLock);
 
    table_close(pg_lo_meta, RowExclusiveLock);
}

References BTEqualStrategyNumber, CatalogTupleDelete(), ereport, errcode(), errmsg(), ERROR, HeapTupleIsValid, ObjectIdGetDatum(), RowExclusiveLock, ScanKeyInit(), systable_beginscan(), systable_endscan(), systable_getnext(), HeapTupleData::t_self, table_close(), and table_open().

Referenced by doDeletion().

LargeObjectExists()

bool LargeObjectExists

(

Oid

loid

)

Definition at line 153 of file pg_largeobject.c.

{
    return LargeObjectExistsWithSnapshot(loid, NULL);
}

References LargeObjectExistsWithSnapshot().

Referenced by get_object_address(), getObjectDescription(), getObjectIdentityParts(), and objectNamesToOids().

LargeObjectExistsWithSnapshot()

bool LargeObjectExistsWithSnapshot	(	Oid	loid,
		Snapshot	snapshot
	)

Definition at line 162 of file pg_largeobject.c.

{
    Relation    pg_lo_meta;
    ScanKeyData skey[1];
    SysScanDesc sd;
    HeapTuple   tuple;
    bool        retval = false;
 
    ScanKeyInit(&skey[0],
                Anum_pg_largeobject_metadata_oid,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(loid));
 
    pg_lo_meta = table_open(LargeObjectMetadataRelationId,
                            AccessShareLock);
 
    sd = systable_beginscan(pg_lo_meta,
                            LargeObjectMetadataOidIndexId, true,
                            snapshot, 1, skey);
 
    tuple = systable_getnext(sd);
    if (HeapTupleIsValid(tuple))
        retval = true;
 
    systable_endscan(sd);
 
    table_close(pg_lo_meta, AccessShareLock);
 
    return retval;
}

References AccessShareLock, BTEqualStrategyNumber, HeapTupleIsValid, ObjectIdGetDatum(), ScanKeyInit(), systable_beginscan(), systable_endscan(), systable_getnext(), table_close(), and table_open().

Referenced by has_lo_priv_byid(), inv_open(), and LargeObjectExists().