gistfile1.swift

public class AtomicProperty<T:Any> {
    
    private var mutex: pthread_mutex_t = {
        var mutex =  pthread_mutex_t()
        pthread_mutex_init(&mutex, nil)
        return mutex
    }()
    
    private var _value: T
    public var value: T {
        get {
            pthread_mutex_lock(&mutex)
            defer { pthread_mutex_unlock(&mutex) }
            
            return _value
        }
        
        set {
            pthread_mutex_lock(&mutex)
            self._value = newValue
            pthread_mutex_unlock(&mutex)
        }
    }
    
    public func mutate(with: (inout T) -> Void ) {
        pthread_mutex_lock(&mutex)
        with(&_value)
        pthread_mutex_unlock(&mutex)
    }
    
    
    public init(initialValue: T) { _value = initialValue }
    
}


var ap = AtomicProperty(initialValue: [String:String]() )

ap.mutate { $0["asdf"] = "asdf" }


ap.value