Re: NSManagedObject, NSString property retain vs copy
On Fri, 31 Jul 2015 12:15:10 +0200, Jean-Daniel Dupas said: Le 30 juil. 2015 à 18:26, Fritz Anderson fri...@manoverboard.org a écrit : On 30 Jul 2015, at 11:03 AM, Trygve Inda cocoa...@xericdesign.com wrote: It seems Apple is using retain rather than copy for NSString properties in an NSManagedObject subclass. I was always under the impression that copy should be used for NSString, so why the retain?? For an immutable string, -copy is implemented as a -retain. -copy is a guard against the receiver’s relying on the unchanging contents of a string whose contents can be changed. If the contents cannot in fact be changed, there’s no point in allocating new memory and copying the bytes into it. It’s an implementation detail; what makes you believe it makes a difference? If it is in the property declaration, it is not an implementation detail, it is part of the public API. And as the receiver can’t guarantee that a passed NSString is not a NSMutableString under the hood, it should always declare property as copy, so the fact that some sample code (I guess this is what the op is talking about) use retain is dubious. This has long been a weakness in the Core Data ecosystem. Even mogenerator does not have an option to make things 'copy': https://github.com/rentzsch/mogenerator/issues/41 I might take a stab at that next week... Cheers, -- Sean McBride, B. Eng s...@rogue-research.com Rogue Researchwww.rogue-research.com Mac Software Developer Montréal, Québec, Canada ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) 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: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: NSManagedObject, NSString property retain vs copy
Le 30 juil. 2015 à 18:26, Fritz Anderson fri...@manoverboard.org a écrit : On 30 Jul 2015, at 11:03 AM, Trygve Inda cocoa...@xericdesign.com wrote: It seems Apple is using retain rather than copy for NSString properties in an NSManagedObject subclass. I was always under the impression that copy should be used for NSString, so why the retain?? For an immutable string, -copy is implemented as a -retain. -copy is a guard against the receiver’s relying on the unchanging contents of a string whose contents can be changed. If the contents cannot in fact be changed, there’s no point in allocating new memory and copying the bytes into it. It’s an implementation detail; what makes you believe it makes a difference? If it is in the property declaration, it is not an implementation detail, it is part of the public API. And as the receiver can’t guarantee that a passed NSString is not a NSMutableString under the hood, it should always declare property as copy, so the fact that some sample code (I guess this is what the op is talking about) use retain is dubious. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) 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: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: NSManagedObject, NSString property retain vs copy
On 30 Jul 2015, at 11:03 AM, Trygve Inda cocoa...@xericdesign.com wrote: It seems Apple is using retain rather than copy for NSString properties in an NSManagedObject subclass. I was always under the impression that copy should be used for NSString, so why the retain?? For an immutable string, -copy is implemented as a -retain. -copy is a guard against the receiver’s relying on the unchanging contents of a string whose contents can be changed. If the contents cannot in fact be changed, there’s no point in allocating new memory and copying the bytes into it. It’s an implementation detail; what makes you believe it makes a difference? — F ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) 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: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
NSManagedObject, NSString property retain vs copy
It seems Apple is using retain rather than copy for NSString properties in an NSManagedObject subclass. I was always under the impression that copy should be used for NSString, so why the retain?? Trygve ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) 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: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: NSManagedObject, NSString property retain vs copy
On Jul 30, 2015, at 9:03 AM, Trygve Inda cocoa...@xericdesign.com wrote: It seems Apple is using retain rather than copy for NSString properties in an NSManagedObject subclass. So, you’re saying that if you store an NSMutableString into a dynamic NSManagedObject property, and then mutate the original string, the property’s value changes too? Do you have a snippet that exhibits this? —Jens ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) 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: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
