UTI.swift

import MobileCoreServices

struct UTI {
    let identifier: String
    
    init(identifier: CFString) {
        self.identifier = identifier as String
    }
    
    init(tagClass: CFString, tag: String) {
        let preferred = UTTypeCreatePreferredIdentifierForTag(tagClass, tag as CFString, nil)
        identifier = preferred!.takeRetainedValue() as String
    }
    
    func conforms(to uti: UTI) -> Bool {
        return UTTypeConformsTo(identifier as CFString, uti.identifier as CFString)
    }
    
    static let pdf = UTI(identifier: kUTTypePDF)
    static let text = UTI(identifier: kUTTypeText)
}