blob: 92383ee1019b55c08278e8f51307bee4ce1dd851 [file] [log] [blame]
// Copyright 2016 The Tulsi Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
import Foundation
extension URL {
public func relativePathTo(_ target: URL) -> String? {
guard self.isFileURL && target.isFileURL else {
return nil
}
let rootComponents = pathComponents
let targetComponents = target.pathComponents
if target == self {
return ""
}
let zippedComponents = zip(rootComponents, targetComponents)
var numCommonComponents = 0
for (a, b) in zippedComponents {
if a != b { break }
numCommonComponents += 1
}
// Construct a path to the last common component.
var relativePath = [String](repeating: "..",
count: rootComponents.count - numCommonComponents)
// Append the path from the common component to the target.
relativePath += targetComponents.suffix(targetComponents.count - numCommonComponents)
return relativePath.joined(separator: "/")
}
}