
<<RollbackImpl.mesa>>
<<Last Edited by: Swinehart, September 16, 1985 9:50:20 am PDT>>
<<>>
DIRECTORY
Atom USING [ MakeAtom ],
Booting USING [ RegisterProcs, CheckpointProc ],
FinchSmarts USING [ PlayNoise ],
Process USING [ Detach, MsecToTicks, Pause ],
UserProfile USING [ Token ]
;

RollbackImpl: CEDAR PROGRAM 
IMPORTS
Atom, Booting, FinchSmarts, Process, UserProfile
= {

reallyBoot: BOOL_TRUE;
didOurBest: BOOL;
maxTime: CARDINAL _ 4000;

PlayTheRollbackButton: Booting.CheckpointProc = TRUSTED {
PlayAButton[$rollback];
IF ~reallyBoot THEN rejection _ "Just pretending";
};

PlayAButton: PROC[name: ATOM] = TRUSTED {
didOurBest _ FALSE;
Process.Detach[FORK ReallyPlayAButton[name]];
FOR i: NAT IN [0..100) DO
Process.Pause[Process.MsecToTicks[maxTime/100]];
IF didOurBest THEN EXIT;
ENDLOOP;
};

ReallyPlayAButton: PROC[name: ATOM] = {
[]_FinchSmarts.PlayNoise[noiseName: name, wait: TRUE];
didOurBest _ TRUE;
};

IF Atom.MakeAtom[UserProfile.Token["Finch.NoisyBoot", "FALSE"]] = $TRUE THEN
Booting.RegisterProcs[c: PlayTheRollbackButton, r: NIL, b: PlayTheRollbackButton];

}.