Background Assets - Access downloads in Exclusive control

Question

tejram_k OP

Created Mar ’23

Replies 1

Boosts 0

Participants 2

I want to run some code in withExclusiveControl and only when the downloads count is 0

Approach 1

manager.fetchCurrentDownloads { downloads, e in
    manager.withExclusiveControl { a, e in
        &#x2F;&#x2F; Here we are in ExclusiveControl but checking for downloads.count == 0 might not give accurate value
    }
}

Approach 2

manager.withExclusiveControl { a, e in
    manager.fetchCurrentDownloads { downloads, e in
        &#x2F;&#x2F; Here we can check for downloads.count == 0, but not actually in ExclusiveControl
    }
}

Can you please let me know how to achieve this?

Answered by Systems Engineer in 749712022

Here you go, added in iOS 16.4. https://developer.apple.com/documentation/backgroundassets/badownloadmanager/4143373-fetchcurrentdownloads

If you need to support older releases, you'll want to use a DispatchSemaphore to make the async version synchronous. I'd highly discourage that approach though as the kernel will be unable to propagate your thread's QoS to the system daemon. The new synchronous API does not have this problem.

Boost

Answer 1

Systems Engineer OP

Apple

Apr ’23

Accepted Answer

Here you go, added in iOS 16.4. https://developer.apple.com/documentation/backgroundassets/badownloadmanager/4143373-fetchcurrentdownloads

If you need to support older releases, you'll want to use a DispatchSemaphore to make the async version synchronous. I'd highly discourage that approach though as the kernel will be unable to propagate your thread's QoS to the system daemon. The new synchronous API does not have this problem.

1