What's the Swift 3 enumerateContentsOfDirectoryAtPath Syntax? (Haneke)

Question

I'm converting the Haneke Cacheing framework to Swift 3 and I've run into a snag with enumerateContentsOfDirectoryAtPath.

Here's the original syntax (view on github),

let fileManager = NSFileManager.defaultManager()
let cachePath = self.path

fileManager.enumerateContentsOfDirectoryAtPath(cachePath, orderedByProperty: NSURLContentModificationDateKey, ascending: true) { (URL : NSURL, _, inout stop : Bool) -> Void in                
    if let path = URL.path {
        self.removeFileAtPath(path) 
        stop = self.size <= self.capacity
    }
}

I believe what I'm looking for is the following function which I found by looking at the FileManger definition, however I don't know how to make the conversion:

public func enumerator(atPath path: String) -> FileManager.DirectoryEnumerator?

Question

What's the Swift 3 equivalent of enumerateContentsOfDirectoryAtPath and how should I use it while converting the above example?

Answer 1

enumerateContensOfDirectoryAtPath is an extension defined by the Haneke framework available here. It's not a standard method for NSFileManager. You need to translate that extension to Swift 3 first:

extension FileManager {

    func enumerateContentsOfDirectoryAtPath(_ path: String, orderedByProperty property: URLResourceKey, ascending: Bool, usingBlock block: (URL, Int, inout Bool) -> Void ) {

        let directoryURL = URL(fileURLWithPath: path)
        do {
            let contents = try self.contentsOfDirectory(at: directoryURL, includingPropertiesForKeys: [property.rawValue], options: FileManager.DirectoryEnumerationOptions())
            let sortedContents = contents.sorted(isOrderedBefore: {(URL1: URL, URL2: URL) -> Bool in

                // Maybe there's a better way to do this. See: http://stackoverflow.com/questions/25502914/comparing-anyobject-in-swift

                var value1 : AnyObject?
                do {
                    try (URL1 as NSURL).getResourceValue(&value1, forKey: property);
                } catch {
                    return true
                }
                var value2 : AnyObject?
                do {
                    try (URL2 as NSURL).getResourceValue(&value2, forKey: property);
                } catch {
                    return false
                }

                if let string1 = value1 as? String, let string2 = value2 as? String {
                    return ascending ? string1 < string2 : string2 < string1
                }

                if let date1 = value1 as? Date, let date2 = value2 as? Date {
                    return ascending ? date1 < date2 : date2 < date1
                }

                if let number1 = value1 as? NSNumber, let number2 = value2 as? NSNumber {
                    return ascending ? number1 < number2 : number2 < number1
                }

                return false
            })

            for (i, v) in sortedContents.enumerated() {
                var stop : Bool = false
                block(v, i, &stop)
                if stop { break }
            }

        } catch {
            Log.error("Failed to list directory", error as NSError)
        }
    }

}

func < (lhs: Date, rhs: Date) -> Bool {
    return lhs.compare(rhs) == ComparisonResult.orderedAscending
}

func < (lhs: NSNumber, rhs: NSNumber) -> Bool {
    return lhs.compare(rhs) == ComparisonResult.orderedAscending
}

Usage:

let fileManager = FileManager.default
let cachePath = self.path

fileManager.enumerateContentsOfDirectoryAtPath(cachePath, orderedByProperty: URLResourceKey.contentModificationDateKey, ascending: true) { (url, _, stop: inout Bool) in
    // ...
}