信号量不等待关闭

Question

因此，我的函数（带有信号量）仅在获取数据之后才返回nil（[]）。我在封闭中更改了semaphore.signal的位置，但是卡住了。我是新手，希望对您有所帮助。还链接了项目的所有详细信息https://github.com/ablmsky/PatentAnalyzer

功能

extension ViewController{
    func dataAndResponse(url: URL?) throws -> [CountryObject] {
        var object: [CountryObject] = []

        guard let urlString = url else { throw NetworkError.url }

        let semaphore = DispatchSemaphore(value: 0)

        URLSession.shared.dataTask(with: urlString){ (data, response, error) in
            DispatchQueue.main.async(execute: {
                guard let data = data else { return }
                guard error == nil else { return }

                do {
                    let decoder =  JSONDecoder()
                    let array = try JSONSerialization.jsonObject(with: data) as? [Any] ?? []
                    let rootElement = array[1]
                    let rootData = try JSONSerialization.data(withJSONObject: rootElement, options: [])
                    let countryObjects = try decoder.decode([CountryObject].self, from: rootData)
                     object = countryObjects
                    print(countryObjects)//only after returning nil, there will be smthng
                } catch let error {
                    print(error)
                }
            })
            semaphore.signal()
            }.resume()
        _ = semaphore.wait(timeout: .distantFuture)
        return object
    }
}

在这里打电话

@IBAction func onButtonClick(_ sender: Any) {
        var inputCountry: String
        let inputYearFrom: Int
        let inputYearTill: Int
        inputCountry = labelView.text!
        inputYearFrom = Int(labelYearFrom.text!)!
        inputYearTill = Int(labelYearTill.text!)!

        countriesResponedResult.url = APIPatentManager.getURL(country: Country(rawValue: inputCountry)!)
        var countryData: [CountryObject] = []// data which i get from response
        do{
            countryData = try dataAndResponse(url: countriesResponedResult.url)//here is data is empty
        } catch let error{
            print(error)
        }
        print(countryData)
        print(inputYearFrom)
        print(inputYearTill)
    }