Re: Sensible way to extend base class?
Re: Sensible way to extend base class?
- Subject: Re: Sensible way to extend base class?
- From: Michael Ash <email@hidden>
- Date: Wed, 20 May 2009 19:11:40 -0400
On Wed, May 20, 2009 at 4:35 PM, Greg Parker <email@hidden> wrote:
> On May 20, 2009, at 6:01 AM, Ken Thomases wrote:
>>
>> It's possible for a category to provide ivar-like functionality. You can
>> maintain a "category variable" in the same manner as one implements a "class
>> variable" in Objective-C: a file-scope static in the implementation file.
>> That variable could be a mapping from A instance pointers to a value (or
>> dictionary of values).
>>
>> It's non-trivial, though. You have to take care of thread safety in
>> maintaining the mapping.
>
> It's also much harder under GC. The "obvious" solutions either leak (because
> the global table keeps stuff alive), or are thread-unsafe (because no amount
> of locks can save your dangling pointer if the collector decides to delete
> the object).
Is there something wrong with using a [NSMapTable
mapTableWithWeakToStrongObjects] in that environment, with appropriate
synchronization, or do you just consider that to be non-obvious?
Mike
_______________________________________________
Cocoa-dev mailing list (email@hidden)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden