DIRECTORYCamelot,YggDID,YggEnvironment,YggInternal;YggLock: CEDAR DEFINITIONS = BEGINLockID: TYPE = YggInternal.LockID;LockSubID: TYPE = YggInternal.LockSubID;nullLockID: LockID = YggInternal.nullLockID;LockMode: TYPE = YggEnvironment.LockMode;MakeLockID: PROC [did: YggDID.DID] RETURNS [lock: LockID];Set: PROC [ trans: YggEnvironment.TransID, lock: LockID, mode: LockMode, wait: BOOL _ FALSE] RETURNS [granted: BOOL];ModeReleasableSet: TYPE = PACKED ARRAY LockMode OF ModeReleasable;ModeReleasable: TYPE = {no, yes} _ no;Release: PROC [trans: YggEnvironment.TransID, lock: LockID,mode: LockMode] RETURNS [released: BOOL];ReleaseTransactionLocks: PROC [trans: YggEnvironment.TransID, directoryOnly: BOOL] RETURNS [numberReleased: INT];Error: ERROR [type: ErrorType];ErrorType: TYPE = {lockUnreleasable, unknown, unknownLock};Failed: ERROR [why: YggEnvironment.LockFailure];TransAborting: ERROR;END.  ¤  YggLock.mesaCopyright Ó 1985, 1988 by Xerox Corporation.  All rights reserved.Last edited byKK on 18-Dec-81 13:41:01MBrown on January 21, 1983 4:43 pmTaft on September 30, 1982 3:01 pmHauser, May 20, 1985 11:10:09 am PDTBob Hagmann December 20, 1988 7:54:39 am PSTConstruct the lock identifier for the did/segment/offsetAcquires lock, in lock mode mode, for transaction trans.Locks come in two types: object and directory.  Normal locking is done on objects.  For directory operations, a separate locking scheme is used.  Holding any kind of object lock on an object in no way implies anything about the directory locks, and vice versa.  Directory locks are temporaryIf the lock cannot immediately be acquired because a conflicting lock is already setby another transaction, and wait=FALSE, RETURNS FALSE.  If wait=TRUE, waitsuntil the lock can be acquired.! Error {lockUnreleasable, unknown};Releases a lock previously set by the same transaction with this mode.! Error {lockUnreleasable, unknown};Releases all locks (or all directory locks) previously set by this transaction.{conflict, timeout}Hauser, March 8, 1985 10:38:48 am PSTNodified, added copyright.Êü  ˜ šœ™IcodešœB™B—šœ™Jšœ™Jšœ"™"Jšœ"™"K™$K™,—J˜ šÏk	˜	Jšœ˜Jšœ˜Jšœ˜Jšœ˜J˜ J˜ —Jšœ	œ˜"˜ Jšœœ˜"Jšœœ˜(šœ,˜,J˜ —Jšœ
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