File DBStoragePrivate.mesa
Copyright © 1985 by Xerox Corporation. All rights reserved.
Last edited by:
MBrown on July 22, 1980 2:19 PM
Cattell on 26-Sep-81 13:51:37
Willie-Sue, February 15, 1985 11:18:26 am PST
Donahue, May 22, 1986 11:21:03 am PDT
DIRECTORY
DBCommon USING[CacheHandle, TID],
DBStorage USING[TupleHandle, FieldHandle];
DBStoragePrivate: CEDAR DEFINITIONS = BEGIN
GetNWordBase:
PROC[x: DBStorage.TupleHandle, f: DBStorage.FieldHandle]
RETURNS[
LONG
POINTER, DBCommon.CacheHandle];
This proc is analogous to ReadNWord, but instead of copying out the value it returns a long pointer to it, locked in the cache. After the value is used, the page must be unlocked.
CAUTION: other operations on the page containing this tuple my invalidate the result pointer without warning. In particular, anything that triggers a compaction will do it. When in doubt, get the base again!
TupleFromTID:
PROC[DBCommon.
TID]
RETURNS[DBStorage.TupleHandle];
Maps a TID in the range [1..DBStorage.MaxSystemTupleID] into the corresponding tuple handle from the system tuple table.
END.--DBStoragePrivate
CHANGE LOG
Created by MBrown on July 22, 1980 2:17 PM
Created to allow access to TuplesetObjects and IndexObjects without performing unnecessary
storage allocation.
Modified by Cattell on 26-Sep-81 13:53:28
Added TupleFromTID.
Changed by Willie-Sue on February 15, 1985
made Cedar, added tioga formatting