-- File DBStorageTuple.mesa -- Last edited by -- MBrown on December 3, 1982 9:14 pm -- Cattell on November 4, 1983 2:27 am DIRECTORY DBCache USING [CacheHandle], DBCommon USING [Segment], DBStorage USING [TupleHandle], DBStorageTID USING [TID]; DBStorageTuple: DEFINITIONS = BEGIN -- This interface defines a collection of operations on DBStorage.TupleObjects that --may be used by storage-level modules that don't export DBStorage.TupleObject. -- Some modules export DBStorage.TupleObject simply to get read access to the TID without --the cost of a procedure call, and use these procedures for other accesses. Init: PROC [freeTuples: NAT]; -- Called from DBStorage.Initialize. Allocate a free pool of freeTuples tuples. ConsTupleObject: PROC [tid: DBStorageTID.TID, cacheHint: DBCache.CacheHandle _ NIL] RETURNS [DBStorage.TupleHandle]; -- Returns a handle for a new tuple object with the given tid and cacheHint. TIDOfTuple: PROC [x: DBStorage.TupleHandle] RETURNS [DBStorageTID.TID]; -- Returns the TID of x. EqualTuple: PROC [x, y: DBStorage.TupleHandle] RETURNS [BOOLEAN]; -- Returns TIDOfTuple[x] = TIDOfTuple[y]. NullTupleHandle: PROC [] RETURNS [DBStorage.TupleHandle]; -- Returns a TupleHandle x such that TIDOfTuple[x] = NullTID. -- No caller should modify the contents of this TupleObject in any way!!! InvalidateMatchingTuples: PROC [x: DBStorage.TupleHandle]; -- For all tuple handles y on active list such that y.tid = x.tid, makes y.tid=NullTID. IsValidTuple: PROC [x: DBStorage.TupleHandle] RETURNS [valid: BOOL]; -- IF DBSegment.IsValidTID[x.tid] THEN RETURN [valid: TRUE] -- ELSE { x.tid _ NullTID; RETURN [valid: FALSE] } InvalidateTuple: PROC [x: DBStorage.TupleHandle]; -- x.tid _ NullTID CallAfterFinishTransaction: PROC [s: DBCommon.Segment]; -- Invalidates (by setting tid = NullTID, cacheHint = NIL) all TupleObjects on the active -- list that reference segment s. PrintTupleObject: PROC [t: DBStorage.TupleHandle]; -- Prints t to debug stream, without a terminating CR. CheckState: PROC [doPrinting: BOOLEAN _ FALSE]; -- Checks internal state of tuple manager; if doPrinting, also prints contents --of tuple manager to debug stream. END.--DBStorageTuple CHANGE LOG Created by MBrown on June 10, 1980 8:14 PM -- Moved TIDOfTupleHandle here from DBStoragePrivateA, defined other apparently useful procs. Changed by MBrown on July 9, 1980 4:32 PM -- Added Invalidate, for use by tuple deletion. Changed by MBrown on August 4, 1980 10:25 PM -- Added ReInitialize, for use by CloseDatabase. Changed by MBrown on August 14, 1980 2:34 PM -- Added CheckState, for debugging convenience. Changed by MBrown on August 20, 1980 8:58 PM -- Added PrintTupleObject. Changed by MBrown on September 12, 1980 2:32 PM -- Added Finalize. Changed by MBrown on 9-Jun-81 16:20:30 -- Conversion to collectable storage: flushed CopyTupleObject, FreeTupleObject, --Finalize. Added NullTupleHandle. Fixed comments about function of ReInitialize. Changed by MBrown on December 2, 1982 2:44 pm -- Added CallAfterFinishTransaction; flushed ReInitialize.