timer with dispatch source

gistfile1.m

typedef void (^loop_work_t)(void);


@interface TaxiLoop : NSObject

@property (nonatomic,assign) loop_work_t block;
@property (nonatomic,assign) NSTimeInterval interval;
@property (nonatomic,assign) dispatch_source_t timerSource;

-(id) initWithInterval:(NSTimeInterval)seconds block:(loop_work_t)block;

-(void) start;
-(void) stop;

@end



#import "TaxiLoop.h"

@implementation TaxiLoop

@synthesize interval=_interval;
@synthesize block=_block;
@synthesize timerSource=_timerSource;


-(id) initWithInterval:(NSTimeInterval)seconds block:(loop_work_t)block 
{
    if (self = [super init]){
        self.interval = seconds;
        self.block = block;
        dispatch_queue_t backgroundQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
        dispatch_source_t timerSource = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, backgroundQueue);
        dispatch_source_set_timer(timerSource, dispatch_time(DISPATCH_TIME_NOW, 0), seconds*NSEC_PER_SEC, 0*NSEC_PER_SEC);
        dispatch_source_set_event_handler(timerSource, ^{
            block();
        });
        self.timerSource = timerSource;
    }
    return self;
}


-(void) start {
    dispatch_resume(self.timerSource);
    debug(@"Taxi update started.");
}


-(void) stop {
    dispatch_suspend(self.timerSource);
    debug(@"Taxi update stopped.");
}


@end