Add TEMP tables/indexes. Add COPY pfree(). Other cleanups.

src/backend/utils/cache/temprel.c

@@ -0,0 +1,165 @@
+/*-------------------------------------------------------------------------
+ *
+ * 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;
+}