TimerEventSample.cpp

/*
    File:       TimerEventSample.cpp
    
    Description:
                A simple sample KEXT that shows how use a timer event source.
                
    Author:     JAS
 
    Copyright:  © Copyright 2001 Apple Computer, Inc. All rights reserved.
    
    Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple Computer, Inc.
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                please do not use, install, modify or redistribute this Apple software.
 
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                copyrights in this original Apple software (the "Apple Software"), to use,
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    Change History (most recent first):
    03/28/01    JAS Created
 
*/
#include <IOKit/IOLib.h>
#include "TimerEventSample.h"
 
 
// REQUIRED! This macro defines the class's constructors, destructors,
// and several other methods I/O Kit requires.  Do NOT use super as the
// second parameter.  You must use the literal name of the superclass.
OSDefineMetaClassAndStructors( TimerEventSample, IOService )
 
// Define my superclass
#define super IOService
 
 
bool TimerEventSample::start(IOService *provider)
{
    bool                result;
    
    IOLog("Starting\n");
    
    result = super::start(provider);
    
    while( result )
    {
        // get our workloop
        myWorkLoop = getWorkLoop();
    
        // get a timer and set our timeout handler to be called when it fires
        myTimer = IOTimerEventSource::timerEventSource( this, (IOTimerEventSource::Action)&TimerEventSample::timeoutHandler );
        
        // make sure we got a timer
        if( !myTimer )
        {
            IOLog( "%s: Failed to create timer event source\n", getName() );
            result = false;
            break;
        }
        
        
        // add the timer to the workloop
        if( myWorkLoop->addEventSource(myTimer) != kIOReturnSuccess )
        {
            IOLog( "%s: Failed to add timer event source to workloop\n", getName() );
            result = false;
            break;
        }
 
        // now set the timeout
        // this example uses 5 seconds
        myTimer->setTimeoutMS( 5000 );
 
        // zero counter
        counter = 0;    // this is used to count the number of times that timeoutHandler is called
        
        break;  // make sure to exit while(result)!!!
    }
    
    return( result );
}
 
void TimerEventSample::stop(IOService *provider)
{
    IOLog("Stopping\n");
    
    // if we got a timer in ::start, clean up
    if( myTimer )
    {
        myTimer->cancelTimeout();                   // stop the timer
        myWorkLoop->removeEventSource( myTimer );   // remove the timer from the workloop
        myTimer->release();                         // release the timer
        myTimer = NULL;                             //
    }
    
    super::stop(provider);
}
 
 
// this function is called when the timer fires
void TimerEventSample::timeoutHandler(OSObject *owner, IOTimerEventSource *sender)
{
    TimerEventSample*   myTimerSample;
    
    // make sure that the owner of the timer is us
    myTimerSample = OSDynamicCast( TimerEventSample, owner );
    if( myTimerSample ) // it's us
    {       
        // increment the counter
        myTimerSample->counter++;
 
        // indicate we were called
        // print the counter as well
        IOLog( "%s: In timeoutHandler (%ld)\n", myTimerSample->getName(), myTimerSample->counter );
        
        // reset the timer for 5 seconds
        sender->setTimeoutMS( 5000 );
    }
} 
 
 
// standard IOKit methods
bool TimerEventSample::init(OSDictionary *dict)
{
    bool res = super::init(dict);
    IOLog("Initializing\n");
    return res;
}
 
void TimerEventSample::free(void)
{
    IOLog("Freeing\n");
    super::free();
}
 
IOService *TimerEventSample::probe(IOService *provider, SInt32  *score)
{
    IOService *res = super::probe(provider, score);
    IOLog("Probing\n");
    return res;
}