[ANN] weak_attr_accessor – gem that adds accessor which wraps objects with WeakRef, for RubyMotion

[Hwee-Boon Yar]

I'm pretty sure everyone has these few lines of code somewhere, but I had to use it for purplish-layout, so..

https://github.com/hboon/weak_attr_accessor

—

Hwee-Boon

http://hboon.com

[Caram Dache]

Excellent !

Adopted already.

Caram

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[Caram Dache]

Hwee-Boon,

Any chance you might check if the WeakRef is not already a weak ref? I have this case where weak_attr_accessor is called twice in succession by Master, Slave1, Slave2 pattern. The app crashes when Slave2 tried to convert into a weak ref, a ref that was already made by weak by Slave1. And I cannot really turn the accessor in Slave2 into a non weak accessor, because Slave2 is also used Slave1b and Slave1b uses a strong ref instead.

Question: how does one check that a ref is weak in the first place?

Caram

Le 1 févr. 2015 à 09:42, Hwee-Boon Yar <hwee...@gmail.com> a écrit :

[Hwee-Boon Yar]

Wrapping a WeakRef with another should work like you expect it to, i.e.

class A
  weak_attr_accessor :w
end
class B
  weak_attr_accessor :w
end
o = NSObject.new
a = A.new
b = B.new
a.w = o
b.w = a.w

Do you have a short example where it wouldn't work correctly?

You can test for a WeakRef by doing:

a.respond_to? 'weakref_alive?'

Did you crash with a "WeakRef::RefError', reason: 'Invalid Reference - probably recycled (WeakRef::RefError)" message? WeakRef in RubyMotion (as well as Ruby) behaves different from a weak reference in Objective C. Zero-ed weak references raises an exception. I noticed that this behavoir is more desirable in my code — since RubyMotion works with iOS — I'm wondering if I should add a check to make it behave similarly.. Thoughts?

–

Hwee-Boon

http://hboon.com

[Caram Dache]

> Wrapping a WeakRef with another should work

You are right indeed.

> Did you crash with a "WeakRef::RefError', reason: 'Invalid Reference - probably recycled (WeakRef::RefError)" message?

Yeah indeed!

> I'm wondering if I should add a check to make it behave similarly.. Thoughts?

Sorry I don’t understand this part. The current crashing behavior seems fine. What did you have in mind exactly?

Caram