/* 

  * tclMacInterupt.c --

  *

  *	This file contains routines that deal with the Macintosh's low level

  *	time manager.  This code provides a better resolution timer than what

  *	can be provided by WaitNextEvent.  

  *

  * Copyright (c) 1996 Sun Microsystems, Inc.

  *

  * See the file "license.terms" for information on usage and redistribution

  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.

  *

  * RCS: @(#) $Id: tclMacInterupt.c,v 1.2 1998/09/14 18:40:05 stanton Exp $

  */

 #include "tclInt.h"

 #include "tclMacInt.h"

 #include <LowMem.h>

 #include <Processes.h>

 #include <Timer.h>

 /*

  * Data structure for timer tasks.

  */

 typedef struct TMInfo {

     TMTask		tmTask;

     ProcessSerialNumber	psn;

     Point 		lastPoint;

     Point 		newPoint;

     long 		currentA5;

     long 		ourA5;

     int			installed;

 } TMInfo;

 /*

  * Globals used within this file.

  */

 static TimerUPP sleepTimerProc = NULL;

 static int interuptsInited = false;

 static ProcessSerialNumber applicationPSN;

 #define MAX_TIMER_ARRAY_SIZE 16

 static TMInfo timerInfoArray[MAX_TIMER_ARRAY_SIZE];

 static int topTimerElement = 0;

 /*

  * Prototypes for procedures that are referenced only in this file:

  */

 #if !GENERATINGCFM

 static TMInfo * 	GetTMInfo(void) ONEWORDINLINE(0x2E89); /* MOVE.L A1,(SP) */

 #endif

 static void		SleepTimerProc _ANSI_ARGS_((void));

 static pascal void	CleanUpExitProc _ANSI_ARGS_((void));

 static void		InitInteruptSystem _ANSI_ARGS_((void));

 /*

  *----------------------------------------------------------------------

  *

  * InitInteruptSystem --

  *

  *	Does various initialization for the functions used in this 

  *	file.  Sets up Universial Pricedure Pointers, installs a trap

  *	patch for ExitToShell, etc.

  *

  * Results:

  *	None.

  *

  * Side effects:

  *	Various initialization.

  *

  *----------------------------------------------------------------------

  */

 void

 InitInteruptSystem()

 {

     int i;

     sleepTimerProc = NewTimerProc(SleepTimerProc);

     GetCurrentProcess(&applicationPSN);

     for (i = 0; i < MAX_TIMER_ARRAY_SIZE; i++) {

 	timerInfoArray[i].installed = false;

     }

     /*

      * Install the ExitToShell patch.  We use this patch instead

      * of the Tcl exit mechanism because we need to ensure that

      * these routines are cleaned up even if we crash or are forced

      * to quit.  There are some circumstances when the Tcl exit

      * handlers may not fire.

      */

     TclMacInstallExitToShellPatch(CleanUpExitProc);

     interuptsInited = true;

 }

 /*

  *----------------------------------------------------------------------

  *

  * TclMacStartTimer --

  *

  *	Install a Time Manager task to wake our process up in the

  *	future.  The process should get a NULL event after ms 

  *	milliseconds.

  *

  * Results:

  *	None.

  *

  * Side effects:

  *	Schedules our process to wake up.

  *

  *----------------------------------------------------------------------

  */

 void *

 TclMacStartTimer(

     long ms)		/* Milliseconds. */

 {

     TMInfo *timerInfoPtr;

     if (!interuptsInited) {

 	InitInteruptSystem();

     }

     /*

      * Obtain a pointer for the timer.  We only allocate up

      * to MAX_TIMER_ARRAY_SIZE timers.  If we are past that

      * max we return NULL.

      */

     if (topTimerElement < MAX_TIMER_ARRAY_SIZE) {

 	timerInfoPtr = &timerInfoArray[topTimerElement];

 	topTimerElement++;

     } else {

 	return NULL;

     }

     /*

      * Install timer to wake process in ms milliseconds.

      */

     timerInfoPtr->tmTask.tmAddr = sleepTimerProc;

     timerInfoPtr->tmTask.tmWakeUp = 0;

     timerInfoPtr->tmTask.tmReserved = 0;

     timerInfoPtr->psn = applicationPSN;

     timerInfoPtr->installed = true;

     InsTime((QElemPtr) timerInfoPtr);

     PrimeTime((QElemPtr) timerInfoPtr, (long) ms);

     return (void *) timerInfoPtr;

 }

 /*

  *----------------------------------------------------------------------

  *

  * TclMacRemoveTimer --

  *

  *	Remove the timer event from the Time Manager.

  *

  * Results:

  *	None.

  *

  * Side effects:

  *	A scheduled timer would be removed.

  *

  *----------------------------------------------------------------------

  */

 void

 TclMacRemoveTimer(

     void * timerToken)		/* Token got from start timer. */

 {

     TMInfo *timerInfoPtr = (TMInfo *) timerToken;

     if (timerInfoPtr == NULL) {

 	return;

     }

     RmvTime((QElemPtr) timerInfoPtr);

     timerInfoPtr->installed = false;

     topTimerElement--;

 }

 /*

  *----------------------------------------------------------------------

  *

  * TclMacTimerExpired --

  *

  *	Check to see if the installed timer has expired.

  *

  * Results:

  *	True if timer has expired, false otherwise.

  *

  * Side effects:

  *	None.

  *

  *----------------------------------------------------------------------

  */

 int

 TclMacTimerExpired(

     void * timerToken)		/* Our token again. */

 {

     TMInfo *timerInfoPtr = (TMInfo *) timerToken;

     if ((timerInfoPtr == NULL) || 

 	!(timerInfoPtr->tmTask.qType & kTMTaskActive)) {

 	return true;

     } else {

 	return false;

     }

 }

 /*

  *----------------------------------------------------------------------

  *

  * SleepTimerProc --

  *

  *	Time proc is called by the is a callback routine placed in the 

  *	system by Tcl_Sleep.  The routine is called at interupt time

  *	and threrfor can not move or allocate memory.  This call will

  *	schedule our process to wake up the next time the process gets

  *	around to consider running it.

  *

  * Results:

  *	None.

  *

  * Side effects:

  *	Schedules our process to wake up.

  *

  *----------------------------------------------------------------------

  */

 static void

 SleepTimerProc()

 {

     /*

      * In CFM code we can access our code directly.  In 68k code that

      * isn't based on CFM we must do a glorious hack.  The function 

      * GetTMInfo is an inline assembler call that moves the pointer 

      * at A1 to the top of the stack.  The Time Manager keeps the TMTask

      * info record there before calling this call back.  In order for

      * this to work the infoPtr argument must be the *last* item on the

      * stack.  If we "piggyback" our data to the TMTask info record we 

      * can get access to the information we need.  While this is really 

      * ugly - it's the way Apple recomends it be done - go figure...

      */

 #if GENERATINGCFM

     WakeUpProcess(&applicationPSN);

 #else

     TMInfo * infoPtr;

     infoPtr = GetTMInfo();

     WakeUpProcess(&infoPtr->psn);

 #endif

 }

 /*

  *----------------------------------------------------------------------

  *

  * CleanUpExitProc --

  *

  *	This procedure is invoked as an exit handler when ExitToShell

  *	is called.  It removes the system level timer handler if it 

  *	is installed.  This must be called or the Mac OS will more than 

  *	likely crash.

  *

  * Results:

  *	None.

  *

  * Side effects:

  *	None.

  *

  *----------------------------------------------------------------------

  */

 static pascal void

 CleanUpExitProc()

 {

     int i;

     for (i = 0; i < MAX_TIMER_ARRAY_SIZE; i++) {

 	if (timerInfoArray[i].installed) {

 	    RmvTime((QElemPtr) &timerInfoArray[i]);

 	    timerInfoArray[i].installed = false;

 	}

     }

 }