PreemptablePaintProcsImpl.mesa
Copyright Ó 1992 by Xerox Corporation. All rights reserved.
Greene, June 14, 1990 7:29 pm PDT
Chauser, June 4, 1992 10:00 am PDT
Christian Jacobi, April 21, 1993 11:53 am PDT
DIRECTORY
Draw2d,
ForkOps,
Imager,
PreemptablePaintProcs,
Process,
ViewerClasses,
ViewerOps;
PreemptablePaintProcsImpl: CEDAR MONITOR LOCKS lc USING lc: LockedContext
IMPORTS ForkOps, Process, ViewerOps, Draw2d
EXPORTS PreemptablePaintProcs =
BEGIN OPEN PreemptablePaintProcs;
nilLockedContext: LockedContext = NEW[LockedContextRec];
NilLockedContext:
PUBLIC
PROC []
RETURNS [LockedContext] ~ {
RETURN[nilLockedContext]};
AbortContext:
PUBLIC
ENTRY
PROC [lc: LockedContext] ~ {
ENABLE UNWIND => NULL;
lc.abort ¬ TRUE; lc.suspend ¬ FALSE; NOTIFY lc.stateHasChanged;
};
SuspendContext:
PUBLIC
ENTRY
PROC [lc: LockedContext] ~ {
ENABLE UNWIND => NULL;
IF NOT lc.abort THEN lc.suspend ¬ TRUE;
};
RestartContext:
PUBLIC
ENTRY
PROC [lc: LockedContext] ~ {
ENABLE UNWIND => NULL;
lc.suspend ¬ FALSE; NOTIFY lc.stateHasChanged;
};
DoUnderLock:
PUBLIC
ENTRY
PROC [lc: LockedContext,
Action: LockedContextActionProc] ~ {
ENABLE UNWIND => NULL;
WHILE lc.suspend DO WAIT lc.stateHasChanged ENDLOOP;
IF lc.abort THEN ERROR ABORTED;
Action[lc.context, lc.zip];
};
PaintWithoutLocks: PUBLIC PROC [self: ViewerClasses.Viewer, context: Imager.Context, whatChanged: REF, clear: BOOL, UnlockedPaint: UnlockedPaintProc, PauseWhilePaint: PauseProc ¬ DefaultPauseWhilePaint, PauseWhileIdle: PauseProc ¬ DefaultPauseWhileIdle] RETURNS [lc: LockedContext]
~
{
{
WITH whatChanged
SELECT
FROM
lockedContext: LockedContext => {
lc ¬ lockedContext;
IF lc.abort THEN RETURN;
lc.context ¬ context;
lc.zip ¬ Draw2d.GetZip[context, lc.zip];
RestartContext[lc];
PauseWhilePaint[];
GOTO Suspend;
};
ENDCASE => {
lc ¬
NEW[LockedContextRec ¬ [
context: context,
zip: Draw2d.GetZip[context],
pauseWhileIdle: PauseWhileIdle,
viewer: self
]];
TRUSTED{Process.Detach[FORK UnlockedPaint[self, lc, whatChanged, clear]]};
PauseWhilePaint[];
GOTO Suspend;
};
EXITS
Suspend => {
SuspendContext[lc];
ForkOps.Fork[DelayThenContinuePaint, lc];
};
}
};
DelayThenContinuePaint:
PROC [data:
REF] ~ {
lc: LockedContext ~ NARROW[data];
IF lc.abort THEN RETURN;
lc.pauseWhileIdle[];
IF lc.abort THEN RETURN;
ViewerOps.PaintViewer[
viewer: lc.viewer,
hint: client,
clearClient: FALSE,
whatChanged: lc
];
};
DefaultPauseWhilePaint: PUBLIC PROC[] ~ {Process.PauseMsec[1000]}; --1 seconds of paint
DefaultPauseWhileIdle: PUBLIC PROC[] ~ {Process.PauseMsec[50]}; --1/25 second idle
END.