iterator_setup.m

- (BOOL) registerForUSBNotificationsVendorId:(long) vendorId productId:(long)productId
{
    CFMutableDictionaryRef matchingDict = IOServiceMatching(kIOUSBDeviceClassName);
    if ( !matchingDict )
        return YES;
    if ( vendorId != 0)
        ((__bridge NSMutableDictionary*)matchingDict)[@"idVendor"] = @(vendorId);
    else
        ((__bridge NSMutableDictionary*)matchingDict)[@"idVendor"] = @"*";
    
    if ( productId != 0)
        ((__bridge NSMutableDictionary*)matchingDict)[@"idProduct"] = @(productId);
    else
        ((__bridge NSMutableDictionary*)matchingDict)[@"idProduct"] = @"*";
    
    mach_port_t masterPort;
    if ( IOMasterPort( MACH_PORT_NULL, &masterPort ) || !masterPort ) {
        CFRelease(matchingDict);
        return YES;
    }
    
    // To set up asynchronous notifications, create a notification port and
    // add its run loop event source to the program’s run loop
    IONotificationPortRef notifyPort = IONotificationPortCreate(masterPort);
    CFRunLoopSourceRef runLoopSource = IONotificationPortGetRunLoopSource(notifyPort);
    CFRunLoopRef gRunLoop = CFRunLoopGetCurrent();
    CFRunLoopAddSource(gRunLoop, runLoopSource, kCFRunLoopDefaultMode);
    
    // Retain additional dictionary references because each call to
    // IOServiceAddMatchingNotification consumes one reference
    CFRetain(matchingDict);
    CFRetain(matchingDict);
    CFRetain(matchingDict);
    
    // Now set up two notifications: one to be called when a raw device
    // is first matched by the I/O Kit and another to be called when the
    // device is terminated
    
    // Notification of first match:
    kern_return_t kr;
    io_iterator_t addedIter;
    kr = IOServiceAddMatchingNotification( notifyPort,
                                          kIOFirstMatchNotification,
                                          matchingDict,
                                          USBDeviceInserted,
                                          NULL,
                                          &addedIter );
    USBDeviceInserted( NULL, addedIter );
    if ( kr ) {
        // Error in IOServiceAddMatchingNotification
        mach_port_deallocate( mach_task_self(), masterPort );
        return YES;
    }
    
    // Notification of termination:
    io_iterator_t removedIter;
    kr = IOServiceAddMatchingNotification( notifyPort,
                                          kIOTerminatedNotification,
                                          matchingDict,
                                          USBDeviceRemoved,
                                          NULL,
                                          &removedIter );
    USBDeviceRemoved( NULL, removedIter );
    if ( kr ) {
        // Error in IOServiceAddMatchingNotification
        mach_port_deallocate( mach_task_self(), masterPort );
        return YES;
    }
    
    mach_port_deallocate( mach_task_self(), masterPort );
    
    return NO;
}