[swift-users] Strong Reference Cycle

[Zhao Xin]

Bar() will be released as soon as start(:)'s finishes execution. As there
is no strong reference to Bar() and the closure runs inside of  function
start(:).

steps:
Bar() created
execute Bar().start(:) with {print(self.object)}
pass closure {print(self.object)} to start(:)
closure runs inside of function start(:)
closure released after its execution
start(:) finished
Bar() released

Zhaoxin


On Sat, Jul 2, 2016 at 6:06 AM, Grzegorz Leszek via swift-users <
swift-users at swift.org> wrote:

> Hello Swift Community,
>
> According to the Swift Programming Language Book:
>
> “A strong reference cycle can also occur if you assign a closure to a
> property of a class instance, and the body of that closure captures
> the instance.”
>
> Excerpt From: Apple Inc. “The Swift Programming Language.” iBooks.
> https://itun.es/pl/jEUH0.l
>
> Does it mean that example below is valid? ( no need to use capture list ):
>
> import Swift
>
> class A {}
>
> class Foo {
>     var object = A()
>     func bar() {
>         Bar().start {
>             print(self.object)
>         }
>     }
> }
>
> class Bar {
>     func start(completion: () -> ()) {
>         completion()
>     }
> }
>
> As far as I understand, Leak will occur when class Bar stores
> completion in the property. But are there any other edge cases ?
>
> Regars,
> Greg Leszek
> _______________________________________________
> swift-users mailing list
> swift-users at swift.org
> https://lists.swift.org/mailman/listinfo/swift-users
>
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