Re: garbage collection and NSConnection

FROM : Jean-Daniel Dupas
DATE : Mon Jun 30 22:19:08 2008

Le 30 juin 08 à 22:10, eblu a écrit :

> Hi Chris,
>     I'm not terribly sure what you are asking for here. From my 
> experience (limited experience admittedly) theres really only one 
> way to use NSConnection.
> its a pretty elegant class, which is simple, and works as expected, 
> except for when garbage collection is enabled.
>
> heres what I do just after NSNetService finds a service:
>
> // Sent when a service appears
> - (void)netServiceBrowser:(NSNetServiceBrowser *)browser
>        didFindService:(NSNetService *)aNetService
>        moreComing:(BOOL)moreComing
> {
>     NSMutableDictionary* newDict = [[NSMutableDictionary alloc] init];
>     [newDict setValue:aNetService forKey:@"theService"];
>     
>     [serverArrayController addObject:newDict];
>     [aNetService setDelegate:self];
>     [aNetService resolveWithTimeout:5];
>    if(!moreComing)
>    {
>    }
> }
>
> // NSNetService Delegate method:
> - (void)netServiceDidResolveAddress:(NSNetService *)sender{
>     
>     id proxy = nil;
>     NSData *addy;
>     NSSocketPort* socket;
>     NSConnection* connection;
>     NSString* hostname;
>     
>     int a;
>     int i;
>     
>     hostname = [sender hostName];
>     socket = (NSSocketPort*)[[NSSocketPortNameServer sharedInstance] 
> portForName:@"BKOtherPort" host:hostname];
>     connection = [NSConnection connectionWithReceivePort: nil sendPort: 
> socket];
>     @try{
>         proxy = [connection rootProxy];
>     }
>     @catch(id exception){
>         proxy = nil;
>
>     }
>     addy = [socket address];
>     if(proxy){
>             // app level stuff if the proxy exists
>     }
> }
>
> pretty straight forward,
> and every time I ran it with garbage collection on, the NSConnection 
> initialized, but NEVER returned the proxy. it returned nil.
> all my instance variables were populated, everything on My end was 
> correct... or at least behaving as expected. it just wouldn't return 
> the proxy object (or the root for that matter)
> All I did to fix it, was to turn off garbage collection.
> That part runs like a champ now.  the rest of the app won't do 
> anything anymore, as it was built on garbage collection.
>
> cheers,
> -eb
>


And did you try using CFNetServices instead ? As it is CF based, it 
probably does not have the same GC problem and is it far more easier 
to replace NSNetService by CFNetService than rewriting the whole 
application without GC .