[swift-corelibs-dev] Asynchronous Operations

[Ian Partridge]

Thank you everyone for your comments.

Adding willChangeValue(forKey:) and didChangeValue(forKey:) to
Operation does solve the problem for me.  The Swift 3 code I'm porting
from macOS to Linux works correctly when I patch Foundation as Brent
suggests.

I've opened a PR against swift-corelibs-foundation and would welcome
feedback on this.  Thank you.

https://github.com/apple/swift-corelibs-foundation/pull/836

P.S. The code I'm porting is roughly analogous to
https://gist.github.com/ianpartridge/e3b8496cb114005a93f5c86ff76af630
although it uses URLSession instead of an async dispatch queue.

On 23 January 2017 at 17:32, Tony Parker <anthony.parker at apple.com> wrote:
> Hm, that’s probably the least bad option we have at the moment.
>
> I don’t want to introduce “new” API, as it is unlikely we will be able to remove it when whatever permanent solution comes up.
>
> - Tony
>
>> On Jan 21, 2017, at 6:09 AM, Brent Royal-Gordon via swift-corelibs-dev <swift-corelibs-dev at swift.org> wrote:
>>
>>> On Jan 20, 2017, at 7:55 AM, Ian Partridge via swift-corelibs-dev <swift-corelibs-dev at swift.org> wrote:
>>>
>>> Is there any way that we could support asynchronous operations in swift-corelibs-foundation, in the absence of KVO?
>>
>> Could we add `willChangeValue(forKey:)` and `didChangeValue(forKey:)` methods just to `Operation` which only handle an `isFinished` key? Presumably they'd just look like:
>>
>>       public func willChangeValue(forKey key: String) {
>>               // do nothing
>>       }
>>       public func didChangeValue(forKey key: String) {
>>               if key == "isFinished" && isFinished {
>>                       finish()
>>               }
>>       }
>>
>> I believe that would make existing code just work without needing to do anything special.
>>
>> --
>> Brent Royal-Gordon
>> Architechies
>>
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>



-- 
Ian Partridge