/* 

 * 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;

	}

    }

}