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/*-------------------------------------------------------------------------
*
* temprel.c--
* POSTGRES temporary relation handling
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/cache/Attic/temprel.c,v 1.1 1999/02/02 03:45:03 momjian Exp $
*
*-------------------------------------------------------------------------
*/
/*
* This implements temp tables by modifying the relname cache lookups
* of pg_class.
* When a temp table is created, a linked list of temp table tuples is
* stored here. When a relname cache lookup is done, references to user-named
* temp tables are converted to the internal temp table names.
*
*/
#include <sys/types.h>
#include <stdio.h>
#include <string.h>
#include "postgres.h"
#include "miscadmin.h"
#include "nodes/pg_list.h"
#include "utils/mcxt.h"
#include "utils/temprel.h"
#include "access/htup.h"
#include "access/heapam.h"
#include "catalog/heap.h"
#include "catalog/index.h"
#include "catalog/pg_class.h"
GlobalMemory CacheCxt;
/* ----------------
* global variables
* ----------------
*/
static List *temp_rels = NIL;
typedef struct TempTable
{
char *user_relname;
HeapTuple pg_class_tuple;
} TempTable;
void
create_temp_relation(char *relname, HeapTuple pg_class_tuple)
{
MemoryContext oldcxt;
TempTable *temp_rel;
oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
temp_rel = palloc(sizeof(TempTable));
temp_rel->user_relname = palloc(NAMEDATALEN);
/* save user-supplied name */
strcpy(temp_rel->user_relname, relname);
temp_rel->pg_class_tuple = heap_copytuple(pg_class_tuple);
temp_rels = lcons(temp_rel, temp_rels);
MemoryContextSwitchTo(oldcxt);
}
void
remove_all_temp_relations(void)
{
List *l, *next;
l = temp_rels;
while (l != NIL)
{
TempTable *temp_rel = lfirst(l);
Form_pg_class classtuple;
classtuple = (Form_pg_class)GETSTRUCT(temp_rel->pg_class_tuple);
next = lnext(l); /* do this first, l is deallocated */
if (classtuple->relkind != RELKIND_INDEX)
{
char relname[NAMEDATALEN];
/* safe from deallocation */
strcpy(relname, temp_rel->user_relname);
heap_destroy_with_catalog(relname);
}
else
index_destroy(temp_rel->pg_class_tuple->t_data->t_oid);
l = next;
}
}
/* we don't have the relname for indexes, so we just pass the oid */
void
remove_temp_relation(Oid relid)
{
MemoryContext oldcxt;
List *l, *prev;
oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
prev = NIL;
l = temp_rels;
while (l != NIL)
{
TempTable *temp_rel = lfirst(l);
if (temp_rel->pg_class_tuple->t_data->t_oid == relid)
{
pfree(temp_rel->user_relname);
pfree(temp_rel->pg_class_tuple);
pfree(temp_rel);
/* remove from linked list */
if (prev != NIL)
{
lnext(prev) = lnext(l);
pfree(l);
l = lnext(prev);
}
else
{
temp_rels = lnext(l);
pfree(l);
l = temp_rels;
}
}
else
{
prev = l;
l = lnext(l);
}
}
MemoryContextSwitchTo(oldcxt);
}
HeapTuple
get_temp_rel_by_name(char *user_relname)
{
List *l;
foreach(l, temp_rels)
{
TempTable *temp_rel = lfirst(l);
if (strcmp(temp_rel->user_relname, user_relname) == 0)
return temp_rel->pg_class_tuple;
}
return NULL;
}
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