Re: Sensible way to extend base class?
Re: Sensible way to extend base class?
- Subject: Re: Sensible way to extend base class?
- From: Greg Parker <email@hidden>
- Date: Wed, 20 May 2009 16:30:25 -0700
On May 20, 2009, at 4:11 PM, Michael Ash wrote:
On Wed, May 20, 2009 at 4:35 PM, Greg Parker <email@hidden>
wrote:
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?
It's much improved over the traditional "CFDictionary with non-
retaining callbacks" scheme, but is still vulnerable to uncollectable
cycles under GC, if I remember correctly. If a table-value can
eventually point back to its table-key, then the objects will never be
reclaimed because of the table's own strong reference to the table-
value.
--
Greg Parker email@hidden Runtime Wrangler
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