Remove headers from all .c .h .m and .swift templates in Xcode.

remove-fileheader.swift

#!/usr/bin/swift
/// Args:
///   --xcode {XCODE_PATH}

import Foundation

extension Array {
    func paired() -> [(Element, Element)] {
        return stride(from: 0, to: count - 1, by: 2).map {
            (self[$0], self[$0 + 1])
        }
    }
}

// naïve, assumes one key per one value
func argDict(fromCommandLineArgs args: [String]) -> [String : String] {
    let tail = Array(args.dropFirst())
    return Dictionary(uniqueKeysWithValues: tail.paired() )
}

// copies the URL if the item does not already exist
func backup(_ url: URL) throws {
    let urlOrig = url.appendingPathExtension("orig")
    try FileManager.default.copyItem(at: url, to: urlOrig)
}

func hasExtension(any exts: [String]) -> (URL) -> Bool {
    return { exts.contains($0.pathExtension) }
}

func removingFileHeader(from str: String) -> String {
    if let r = str.range(of: "//___FILEHEADER___\n\n") {
        var new = str
        new.removeSubrange(r)
        return new
    }
    return str
}

func urls(enumerator: FileManager.DirectoryEnumerator) -> [URL] {
    var ret = [URL]()
    while let url = enumerator.nextObject() as? URL {
        ret.append(url)
    }
    return ret
}

// MARK: Do it

let argsDict = argDict(fromCommandLineArgs: CommandLine.arguments)
let userXcodePath = argsDict["--xcode"].map(URL.init(fileURLWithPath:))
guard let xcodePath = userXcodePath else {
    print("""
Please point me to an Xcode app you'd like to patch. Use '--xcode {XCODE_PATH}'. For example,

    ./remove-fileheader.swift --xcode /Applications/Xcode.app

""")
    exit(0)
}

let templates = xcodePath.appendingPathComponent("Contents/Developer/Library/Xcode/Templates/File Templates/Source", isDirectory: true)
try? backup(templates)

guard let en = FileManager.default.enumerator(at: templates, includingPropertiesForKeys: nil) else {
    print("ABORT: Could not enumerate template dir: \(templates)")
    exit(0)
}

let all = urls(enumerator: en)
let code = all.filter(hasExtension(any: ["c", "h", "m", "swift"]))

code.forEach { url in
    let str = try! String(contentsOf: url)
    let new = removingFileHeader(from: str)
    try! new.write(to: url, atomically: true, encoding: .utf8)
}