XlTQPrivate.mesa
Copyright Ó 1990, 1991, 1992 by Xerox Corporation. All rights reserved.
Created by Christian Jacobi, March 28, 1990
Christian Jacobi, June 15, 1992 5:16 pm PDT
DIRECTORY Xl, Process;
XlTQPrivate: CEDAR DEFINITIONS
~ BEGIN
PRIVATE to XlImplTQ; recompiled outside of "release"
TQRec: TYPE = MONITORED RECORD [
--type which implements Xl.TQRep
selfProcess: PROCESS, -- process executing queued events
selfRunning: BOOL ¬ FALSE, -- process (selfProcess) exists or will come into existence soon
selfRunning2: BOOL ¬ FALSE, --
lockProcess: PROCESS, -- process holding lock [defined if lockCount>0 and ~selfProcess]
lockCount: CARD ¬ 0, -- number of locks of processes [defined if ~selfProcess];
  -- lock is free if lockCount=0 AND ~this=NIL
eventCount: CARD ¬ 0, -- number of queued but not yet handled events
next: Job ¬ NIL,  -- the next event to be handled
tail: Job ¬ NIL, -- for fast inclusion at end of tail
newEvent: CONDITION, -- running process sleeps before disappearing
lockWaiterCond: CONDITION, -- waiting for change in lock state
lockWaiterCount: INT ¬ 0, -- number of processes waiting on lockWaiterCond
upperLimit: CARD ¬2000, -- if there are more events we start throwing some away
this: Job ¬ NIL, -- Job in execution right now
free: Job ¬ NIL, -- list of free entries
freeCnt: CARD ¬ 0, -- number of entries on free list
order: INT ¬ 0,  -- lock order
seq1, seq2: INT ¬ 0,  -- lock order
dead: BOOL ¬ FALSE,  -- set using debugger; useful to reduce number of hanging resources
props: <<PRIVATE>> REF ¬ NIL, --reserved for property list
priority: Process.Priority ¬ Process.priorityForeground, --used after fork only
createData: REF ¬ NIL -- useful for debugging
];
Job: TYPE = REF JobRec;
JobRec: TYPE = RECORD [event: Xl.Event, proc: Xl.EventProcType, data: REF, next: Job ¬ NIL];
Regular usage: to record queued entries
DirtyPeekNextIsMouseEvent: PROC [tq: Xl.TQ] RETURNS [BOOL] = TRUSTED INLINE {
--To work without lock, this must be called running on tq
next: Job ¬ LOOPHOLE[tq, REF TQRec].next;
RETURN [next#NIL AND next.event#NIL AND next.event.type=motionNotify]
};
SetTQReadiness: PROC [tq: Xl.TQ, ms: INT];
--TQ stays ready to start up fast for ms milliseconds after last job
SetTQPriority: PROC [tq: Xl.TQ, priority: Process.Priority];
--New priority is set only when freshly forked
RemoveErrorEvents: PROC [tq: Xl.TQ]
--Removes all leading error events
--Use when interactively required while debugging
END.