CODEWITHSUNDEEP
iosswiftmemory-leaksnsurlsession
Sujesh Surya
Sujesh Surya

Reputation: 163

Swift Memory Leaks

I need some help in identifying what's causing these memory leak's. I created a simple program to invoke an api and get data. It works as expected. But in instrument i get memory leak's. I have been trying hard to identify whats causing this memory leak, but no luck. I also tried in Debug Memory graph, when i filter "Show Only Leaked Blocks", there are no blocks displayed. Below is the code and screen shot from Instrument:

import UIKit

class ViewController: UIViewController {

    struct main_struct {
         var ACCEPT_DATE: String

         init(_ dictionary: [String: Any]) {

             self.ACCEPT_DATE = dictionary["ACCEPT_DATE"] as? String ?? " "

         }
     }

    var main_array = [main_struct]()

    override func viewDidLoad() {
        super.viewDidLoad()
        let Endpoint: String = "http://mylink.com"
        let url = URL(string: Endpoint)
        downloaddatafromurl(url: url!, completionhandler: { [weak self] (data, response: URLResponse, Error) -> Void in

            if Error != nil {
                print("error in API Connect")
            }
            let jsondata = try?  JSONSerialization.jsonObject(with: data, options: .mutableContainers) as? [String : NSArray]
            let arrayJSON = jsondata?["apidata"]
            for dict in arrayJSON! {
                self!.main_array.append(main_struct(dict as! [String : Any]))
            }

            //print(data)
            print(response)
        })



    }

    func downloaddatafromurl(url: URL, completionhandler: @escaping (Data, URLResponse , Error? ) -> Void) {

        let session = URLSession.shared
        let task = session.dataTask(with: url, completionHandler: {data, response, error -> Void in
            DispatchQueue.global().async {
                completionhandler (data!, response!, error)
            }
        })
        task.resume()
        session.finishTasksAndInvalidate()
    }
}

Screenshot from Instrument:

Screenshot from Instrument

Upvotes: 1

Views: 2101

Answers (1)

Ammar
Ammar

Reputation: 380

You can track memory leaks with Instruments: see this tutorial.

If you're familiar with Valgrind, you use it on x86 binaries built against the iPhone Simulator SDK: see how Landon Fuller does it.

Another Stackoverflow answer suggests the Clang analyser: static analysis of the code may detect memory allocation errors as well. I never used this tool myself but it's good to know it's possible.

Also also Apple's Introduction to Instruments User Guide

Upvotes: 1

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