Merge pull request #42 from mxcl/path-components

Add Path.components

.github/deploy

@@ -0,0 +1,168 @@
+#!/usr/bin/swift sh
+import func Darwin.fputs
+import var Darwin.stderr
+import PMKFoundation  // PromiseKit/Foundation ~> 3.3
+import LegibleError   // @mxcl ~> 1.0
+import Foundation
+import PromiseKit     // @mxcl ~> 6.8
+import Path           // mxcl/Path.swift ~> 0.15
+
+let env = ProcessInfo.processInfo.environment
+let token = env["GITHUB_TOKEN"] ?? env["GITHUB_ACCESS_TOKEN"]!
+let slug = env["TRAVIS_REPO_SLUG"]!
+let tag = env["TRAVIS_TAG"]!
+
+func fatal(message: String) -> Never {
+    fputs("error: \(message)\n", stderr)
+    exit(1)
+}
+func fatal(error: Error) -> Never {
+    fatal(message: "\(error.legibleLocalizedDescription)\n\n\(error.legibleDescription)")
+}
+
+struct Repo: Decodable {
+    let description: String
+    let license: License
+    struct License: Decodable {
+        let spdx_id: String
+    }
+}
+
+struct Package: Decodable {
+    let swiftLanguageVersions: [String]
+    let targets: [Target]
+    struct Target: Decodable {
+        let path: String?
+        let type: Kind
+        enum Kind: String, Decodable {
+            case regular
+            case test
+        }
+    }
+}
+
+extension URLRequest {
+    init(github path: String) {
+        let url = URL(string: "https://api.github.com\(path)")!
+        self.init(url: url)
+        setValue("token \(token)", forHTTPHeaderField: "Authorization")
+        setValue("application/json", forHTTPHeaderField: "Content-Type")
+        setValue("application/json", forHTTPHeaderField: "Accept")
+    }
+}
+
+func description() -> Promise<Repo> {
+    let rq = URLRequest(github: "/repos/\(slug)")
+    return firstly {
+        URLSession.shared.dataTask(.promise, with: rq).validate()
+    }.map { data, _ in
+        try JSONDecoder().decode(Repo.self, from: data)
+    }
+}
+
+struct User: Decodable {
+    let name: String
+    let email: String
+}
+
+func email() -> Promise<User> {
+    let rq = URLRequest(github: "/user")
+    return firstly {
+        URLSession.shared.dataTask(.promise, with: rq).validate()
+    }.map { data, _ in
+        try JSONDecoder().decode(User.self, from: data)
+    }
+}
+
+func dumpPackage() -> Promise<Package> {
+    let task = Process()
+    task.launchPath = "/usr/bin/swift"
+    task.arguments = ["package", "dump-package"]
+    return firstly {
+        task.launch(.promise)
+    }.map { out, _ in
+        out.fileHandleForReading.readDataToEndOfFile()
+    }.map { data in
+        try JSONDecoder().decode(Package.self, from: data)
+    }
+}
+
+var defaultSwiftVersion: String {
+    let task = Process()
+    task.launchPath = "/usr/bin/swift"
+    task.arguments = ["--version"]
+
+    func extract(input: String) -> String {
+        let range = input.range(of: #"Apple Swift version \d+\.\d+"#, options: .regularExpression)!
+        return String(input[range].split(separator: " ").last!)
+    }
+
+    return try! firstly {
+        task.launch(.promise)
+    }.compactMap { out, _ in
+        String(data: out.fileHandleForReading.readDataToEndOfFile(), encoding: .utf8)
+    }.map { out in
+        extract(input: out)
+    }.wait()
+}
+
+func podspec(repo: Repo, user: User, pkg: Package) -> (Substring, String) {
+    let (owner, name) = { ($0[0], $0[1]) }(slug.split(separator: "/"))
+    let swiftVersion = pkg.swiftLanguageVersions.min() ?? defaultSwiftVersion
+    let targets = pkg.targets.filter{ $0.type == .regular }
+    guard targets.count == 1 else { fatal(message: "Too many targets for this script!") }
+    guard let sources = targets[0].path else { fatal(message: "Target has no path!") }
+    return (name, """
+    Pod::Spec.new do |s|
+      s.name = '\(name)'
+      s.version = '\(tag)'
+      s.summary = '\(repo.description)'
+      s.homepage = "https://github.com/\(slug)"
+      s.license = '\(repo.license.spdx_id)'
+      s.author = { '\(user.name)': '\(user.email)' }
+      s.source = { git: "https://github.com/\(slug).git", tag: '\(tag)' }
+      s.social_media_url = 'https://twitter.com/\(owner)'
+      s.osx.deployment_target = '10.10'
+      s.ios.deployment_target = '8.0'
+      s.tvos.deployment_target = '9.0'
+      s.watchos.deployment_target = '2.0'
+      s.source_files = '\(sources)/*.swift'
+      s.swift_version = '\(swiftVersion)'
+    end
+    """)
+}
+
+func publishRelease() throws -> Promise<Void> {
+    struct Input: Encodable {
+        let tag_name = tag
+        let name = tag
+        let body = ""
+    }
+
+    var rq = URLRequest(github: "/repos/\(slug)/releases")
+    rq.httpMethod = "POST"
+    rq.httpBody = try JSONEncoder().encode(Input())
+    return URLSession.shared.dataTask(.promise, with: rq).validate().asVoid()
+}
+
+switch CommandLine.arguments[1] {
+case "generate-podspec":
+    firstly {
+        when(fulfilled: description(), email(), dumpPackage())
+    }.map(podspec).done { name, podspec in
+        try podspec.write(toFile: "\(name).podspec", atomically: false, encoding: .utf8)
+        exit(0)
+    }.catch {
+        fatal(error: $0)
+    }
+case "publish-release":
+    try publishRelease().done {
+        exit(0)
+    }.catch {
+        fatal(error: $0)
+    }
+default:
+    fatal(message: "invalid usage")
+}
+
+RunLoop.main.run()

.github/jazzy.yml

@@ -0,0 +1,13 @@
+module: Path
+custom_categories:
+  - name: Path
+    children:
+      - Path
+      - /(_:_:)
+xcodebuild_arguments:
+  - UseModernBuildSystem=NO
+output:
+  ../output
+  # output directory is relative to config file… ugh
+exclude:
+  - Sources/Path+StringConvertibles.swift

.travis.yml

@@ -15,17 +15,26 @@ xcode_scheme: Path.swift-Package
 
 jobs:
   include:
-    - script: swift test --parallel
+    - name: macOS / Swift 4.0.3
-      name: macOS / Swift 4.2.1
+      script: swift test --parallel -Xswiftc -swift-version -Xswiftc 4
+
+    - name: macOS / Swift 4.2.1
+      script: swift test --parallel
+
+    - name: macOS / Swift 5.0
+      osx_image: xcode10.2
+      script: swift test --parallel
 
     - &xcodebuild
       before_install: swift package generate-xcodeproj --enable-code-coverage
       xcode_destination: platform=iOS Simulator,OS=latest,name=iPhone XS
       name: iOS / Swift 4.2.1
       after_success: bash <(curl -s https://codecov.io/bash)
+
     - <<: *xcodebuild
       xcode_destination: platform=tvOS Simulator,OS=latest,name=Apple TV
       name: tvOS / Swift 4.2.1
+
     - <<: *xcodebuild
       name: watchOS / Swift 4.2.1
       script: |
@@ -49,7 +58,7 @@ jobs:
 
     - <<: *linux
       env: SWIFT_VERSION='5.0-DEVELOPMENT-SNAPSHOT-2019-01-22-a'
-      name: Linux / Swift 5.0.0-dev (2019-01-22)
+      name: Linux / Swift 5.0.0-dev+2019.01.22
 
     - stage: pretest
       name: Check Linux tests are sync’d
@@ -58,29 +67,12 @@ jobs:
 
     - stage: deploy
       name: Jazzy
-      before_install: |
-        cat <<\ \ EOF> .jazzy.yaml
-        module: Path
-        module_version: TRAVIS_TAG
-        custom_categories:
-          - name: Path
-            children:
-              - Path
-              - /(_:_:)
-        xcodebuild_arguments:
-          - UseModernBuildSystem=NO
-        output: output
-        github_url: https://github.com/mxcl/Path.swift
-        exclude:
-          - Sources/Path+StringConvertibles.swift
-        EOF
-        sed -i '' "s/TRAVIS_TAG/$TRAVIS_TAG/" .jazzy.yaml
-      # ^^ this weirdness because Travis multiline YAML is broken and inserts
-      # two spaces in front of the output which means we need a prefixed
-      # delimiter which also weirdly stops bash from doing variable substitution
       install: gem install jazzy
       before_script: swift package generate-xcodeproj
-      script: jazzy
+      script: |
+        jazzy --config .github/jazzy.yml \
+              --module-version $TRAVIS_TAG \
+              --github_url "https://github.com/$TRAVIS_REPO_SLUG"
       deploy:
         provider: pages
         skip-cleanup: true
@@ -90,41 +82,8 @@ jobs:
           tags: true
 
     - name: CocoaPods
-      before_install: |
+      osx_image: xcode10.2
-        export DESCRIPTION=$(swift - <<\ \ EOF
+      install: brew install mxcl/made/swift-sh
-          import Foundation
+      before_script: .github/deploy generate-podspec
-          struct Response: Decodable { let description: String }
-          let token = ProcessInfo.processInfo.environment["GITHUB_TOKEN"]!
-          let url = URL(string: "https://api.github.com/repos/mxcl/Path.swift")!
-          var rq = URLRequest(url: url)
-          rq.setValue("token \(token)", forHTTPHeaderField: "Authorization")
-          let semaphore = DispatchSemaphore(value: 0)
-          var data: Data!
-          URLSession.shared.dataTask(with: rq) { d, _, _ in
-              data = d
-              semaphore.signal()
-          }.resume()
-          semaphore.wait()
-          let rsp = try JSONDecoder().decode(Response.self, from: data)
-          print(rsp.description, terminator: "")
-        EOF)
-        cat <<\ \ EOF> Path.swift.podspec
-        Pod::Spec.new do |s|
-          s.name = 'Path.swift'
-          s.version = ENV['TRAVIS_TAG']
-          s.summary = ENV['DESCRIPTION']
-          s.homepage = 'https://github.com/mxcl/Path.swift'
-          s.license = { :type => 'Unlicense', :file => 'LICENSE.md' }
-          s.author = { 'mxcl' => 'mxcl@me.com' }
-          s.source = { :git => 'https://github.com/mxcl/Path.swift.git', :tag => s.version.to_s }
-          s.social_media_url = 'https://twitter.com/mxcl'
-          s.osx.deployment_target = '10.10'
-          s.ios.deployment_target = '8.0'
-          s.tvos.deployment_target = '10.0'
-          s.watchos.deployment_target = '3.0'
-          s.source_files = 'Sources/*'
-          s.swift_version = '4.2'
-        end
-        EOF
-      install: gem install cocoapods --pre
       script: pod trunk push
+      after_success: .github/deploy publish-release

Package.swift

@@ -1,7 +1,7 @@
 // swift-tools-version:4.2
 import PackageDescription
 
-let package = Package(
+let pkg = Package(
     name: "Path.swift",
     products: [
         .library(name: "Path", targets: ["Path"]),
@@ -9,5 +9,6 @@ let package = Package(
     targets: [
         .target(name: "Path", path: "Sources"),
         .testTarget(name: "PathTests", dependencies: ["Path"]),
-    ]
+    ],
+    swiftLanguageVersions: [.v4, .v4_2, .version("5")]
 )

Package@swift-5.0.swift

@@ -1,20 +0,0 @@
-// swift-tools-version:5.0
-import PackageDescription
-
-let pkg = Package(
-    name: "Path.swift",
-    products: [
-        .library(name: "Path", targets: ["Path"]),
-    ],
-    targets: [
-        .target(name: "Path", path: "Sources"),
-        .testTarget(name: "PathTests", dependencies: ["Path"]),
-    ]
-)
-
-pkg.platforms = [
-   .macOS(.v10_10), .iOS(.v8), .tvOS(.v10), .watchOS(.v3)
-]
-pkg.swiftLanguageVersions = [
-    .v4_2, .v5
-]

README.md

@@ -1,4 +1,4 @@
-# Path.swift ![badge-platforms][] ![badge-languages][] [![badge-ci][]][travis] [![badge-jazzy][]][docs] [![badge-codecov][]][codecov] ![badge-version][]
+# Path.swift ![badge-platforms][] ![badge-languages][] [![badge-ci][]][travis] [![badge-jazzy][]][docs] [![badge-codecov][]][codecov] [![badge-version][]][cocoapods]
 
 A file-system pathing library focused on developer experience and robust end
 results.
@@ -36,7 +36,7 @@ print(foo.isFile)  // => true
 let prefs = Path.home.Library.Preferences  // => /Users/mxcl/Library/Preferences
 
 // a practical example: installing a helper executable
-try Bundle.resources.join("helper").copy(into: Path.home.join(".local/bin").mkdir(.p)).chmod(0o500)
+try Bundle.resources.helper.copy(into: Path.root.usr.local.bin).chmod(0o500)
 ```
 
 We emphasize safety and correctness, just like Swift, and also (again like
@@ -57,7 +57,8 @@ help me continue my work, I appreciate it x
 
 # Handbook
 
-Our [online API documentation][docs] is automatically updated for new releases.
+Our [online API documentation][docs] covers 100% of our public API and is
+automatically updated for new releases.
 
 ## Codable
 
@@ -177,6 +178,11 @@ check the POSIX permissions of the file first, before returning the result of
 `isExecutableFile`. `Path.swift` has done the leg-work for you so you can get on
 with your work without worries.
 
+There is also some magic going on in Foundation’s filesystem APIs, which we look
+for and ensure our API is deterministic, eg. [this test].
+
+[this test]: https://github.com/mxcl/Path.swift/blob/master/Tests/PathTests/PathTests.swift#L539-L554
+
 # `Path.swift` is properly cross-platform
 
 `FileManager` on Linux is full of holes. We have found the holes and worked
@@ -198,6 +204,10 @@ Path.home/"b/c"    // => /Users/mxcl/b/c
 // joining with absolute paths omits prefixed slash
 Path.home/"/b"     // => /Users/mxcl/b
 
+// joining with .. or . works as expected
+Path.home.foo.bar.join("..")  // => /Users/mxcl/foo
+Path.home.foo.bar.join(".")   // => /Users/mxcl/foo/bar
+
 // of course, feel free to join variables:
 let b = "b"
 let c = "c"
@@ -210,8 +220,24 @@ Path.root/"~/b"    // => /~/b
 // but is here
 Path("~/foo")!     // => /Users/mxcl/foo
 
-// this does not work though
+// this works provided the user `Guest` exists
+Path("~Guest")     // => /Users/Guest
+
+// but if the user does not exist
 Path("~foo")       // => nil
+
+// paths with .. or . are resolved
+Path("/foo/bar/../baz")  // => /foo/baz
+
+// symlinks are not resolved
+Path.root.bar.symlink(as: "foo")
+Path("foo")        // => /foo
+Path.foo           // => /foo
+
+// unless you do it explicitly
+try Path.foo.readlink()  // => /bar
+                         // `readlink` only resolves the *final* path component,
+                         // thus use `realpath` if there are multiple symlinks
 ```
 
 *Path.swift* has the general policy that if the desired end result preexists,
@@ -219,30 +245,71 @@ then it’s a noop:
 
 * If you try to delete a file, but the file doesn't exist, we do nothing.
 * If you try to make a directory and it already exists, we do nothing.
+* If you call `readlink` on a non-symlink, we return `self`
 
 However notably if you try to copy or move a file with specifying `overwrite`
 and the file already exists at the destination and is identical, we don’t check
 for that as the check was deemed too expensive to be worthwhile.
 
+## Symbolic links
+
+* Two paths may represent the same *resolved* path yet not be equal due to
+    symlinks in such cases you should use `realpath` on both first if an
+    equality check is required.
+* There are several symlink paths on Mac that are typically automatically
+    resolved by Foundation, eg. `/private`, we attempt to do the same for
+    functions that you would expect it (notably `realpath`), but we do *not* for
+    `Path.init`, *nor* if you are joining a path that ends up being one of these
+    paths, (eg. `Path.root.join("var/private')`).
+
+## We do not provide change directory functionality
+
+Changing directory is dangerous, you should *always* try to avoid it and thus
+we don’t even provide the method. If you are executing a sub-process then
+use `Process.currentDirectoryURL`.
+
+If you must then use `FileManager.changeCurrentDirectory`.
+
+# I thought I should only use `URL`s?
+
+Apple recommend this because they provide a magic translation for
+[file-references embodied by URLs][file-refs], which gives you URLs like so:
+
+    file:///.file/id=6571367.15106761
+
+Therefore, if you are not using this feature you are fine. If you have URLs the correct
+way to get a `Path` is:
+
+```swift
+if let path = Path(url: url) {
+    /*…*/
+}
+```
+
+Our initializer calls `path` on the URL which resolves any reference to an
+actual filesystem path, however we also check the URL has a `file` scheme first.
+
+[file-refs]: https://developer.apple.com/documentation/foundation/nsurl/1408631-filereferenceurl
+
 # Installation
 
 SwiftPM:
 
 ```swift
-package.append(.package(url: "https://github.com/mxcl/Path.swift", from: "0.5.0"))
+package.append(.package(url: "https://github.com/mxcl/Path.swift.git", from: "0.13.0"))
 ```
 
 CocoaPods:
 
 ```ruby
-pod 'Path.swift', '~> 0.5'
+pod 'Path.swift', '~> 0.13'
 ```
 
 Carthage:
 
 > Waiting on: [@Carthage#1945](https://github.com/Carthage/Carthage/pull/1945).
 
-## Please note
+## Pre‐1.0 status
 
 We are pre 1.0, thus we can change the API as we like, and we will (to the
 pursuit of getting it *right*)! We will tag 1.0 as soon as possible.
@@ -253,6 +320,7 @@ https://codebasesaga.com/canopy/
 
 # Alternatives
 
+* [Pathos](https://github.com/dduan/Pathos) by Daniel Duan
 * [PathKit](https://github.com/kylef/PathKit) by Kyle Fuller
 * [Files](https://github.com/JohnSundell/Files) by John Sundell
 * [Utility](https://github.com/apple/swift-package-manager) by Apple
@@ -267,3 +335,4 @@ https://codebasesaga.com/canopy/
 [travis]: https://travis-ci.com/mxcl/Path.swift
 [codecov]: https://codecov.io/gh/mxcl/Path.swift
 [badge-version]: https://img.shields.io/cocoapods/v/Path.swift.svg?label=version
+[cocoapods]: https://cocoapods.org/pods/Path.swift

Sources/Extensions.swift

@@ -9,32 +9,25 @@ public extension Bundle {
         return str.flatMap(Path.init)
     }
 
-    /// Returns the path for the shared-frameworks directory in this bundle.
+    /**
+     Returns the path for the shared-frameworks directory in this bundle.
+     - Note: This is typically `ShareFrameworks`
+    */
     var sharedFrameworks: Path {
-        var `default`: Path {
+        return sharedFrameworksPath.flatMap(Path.init) ?? defaultSharedFrameworksPath
-          #if os(macOS)
+    }
-            return path.join("Contents/Frameworks")
+
-          #elseif os(Linux)
+    /**
-            return path.join("lib")
+     Returns the path for the private-frameworks directory in this bundle.
-          #else
+     - Note: This is typically `Frameworks`
-            return path.join("Frameworks")
+    */
-          #endif
+    var privateFrameworks: Path {
-        }
+        return privateFrameworksPath.flatMap(Path.init) ?? defaultSharedFrameworksPath
-        return sharedFrameworksPath.flatMap(Path.init) ?? `default`
     }
 
     /// Returns the path for the resources directory in this bundle.
     var resources: Path {
-        var `default`: Path {
+        return resourcePath.flatMap(Path.init) ?? defaultResourcesPath
-          #if os(macOS)
-            return path.join("Contents/Resources")
-          #elseif os(Linux)
-            return path.join("share")
-          #else
-            return path
-          #endif
-        }
-        return resourcePath.flatMap(Path.init) ?? `default`
     }
 
     /// Returns the path for this bundle.
@@ -107,3 +100,25 @@ public extension FileHandle {
         try self.init(forUpdating: path.url)
     }
 }
+
+internal extension Bundle {
+    var defaultSharedFrameworksPath: Path {
+      #if os(macOS)
+        return path.join("Contents/Frameworks")
+      #elseif os(Linux)
+        return path.join("lib")
+      #else
+        return path.join("Frameworks")
+      #endif
+    }
+
+    var defaultResourcesPath: Path {
+      #if os(macOS)
+        return path.join("Contents/Resources")
+      #elseif os(Linux)
+        return path.join("share")
+      #else
+        return path
+      #endif
+    }
+}

Sources/Path+Attributes.swift

@@ -1,7 +1,4 @@
 import Foundation
-//#if os(Linux)
-//import func Glibc.chmod
-//#endif
 
 public extension Path {
     //MARK: Filesystem Attributes
@@ -40,15 +37,12 @@ public extension Path {
      */
     @discardableResult
     func chmod(_ octal: Int) throws -> Path {
-//    #if os(Linux)
-//        Glibc.chmod(string, __mode_t(octal))
-//    #else
         try FileManager.default.setAttributes([.posixPermissions: octal], ofItemAtPath: string)
-//    #endif
         return self
     }
     
     /**
+     Applies the macOS filesystem “lock” attribute.
      - Note: If file is already locked, does nothing.
      - Note: If file doesn’t exist, throws.
      - Important: On Linux does nothing.
@@ -70,6 +64,7 @@ public extension Path {
      - Note: If file isn‘t locked, does nothing.
      - Note: If file doesn’t exist, does nothing.
      - Important: On Linux does nothing.
+     - SeeAlso: `lock()`
      */
     @discardableResult
     func unlock() throws -> Path {

Sources/Path+CommonDirectories.swift

@@ -47,18 +47,7 @@ extension Path {
             fatalError()
         }
     #else    
-        guard let pathString = FileManager.default.urls(for: searchPath, in: .userDomainMask).first?.path else {
+        guard let pathString = FileManager.default.urls(for: searchPath, in: .userDomainMask).first?.path else { return defaultUrl(for: searchPath) }
-            switch searchPath {
-            case .documentDirectory:
-                return Path.home/"Documents"
-            case .applicationSupportDirectory:
-                return Path.home/"Library/Application Support"
-            case .cachesDirectory:
-                return Path.home/"Library/Caches"
-            default:
-                fatalError()
-            }
-        }
         return Path(string: pathString)
     #endif
     }
@@ -90,3 +79,19 @@ extension Path {
         return path(for: .applicationSupportDirectory)
     }
 }
+
+#if !os(Linux)
+func defaultUrl(for searchPath: FileManager.SearchPathDirectory) -> Path {
+    switch searchPath {
+    case .documentDirectory:
+        return Path.home/"Documents"
+    case .applicationSupportDirectory:
+        return Path.home/"Library/Application Support"
+    case .cachesDirectory:
+        return Path.home/"Library/Caches"
+    default:
+        fatalError()
+    }
+}
+#endif
+

Sources/Path+FileManager.swift

@@ -1,4 +1,7 @@
 import Foundation
+#if os(Linux)
+import Glibc
+#endif
 
 public extension Path {
     //MARK: File Management
@@ -25,6 +28,11 @@ public extension Path {
         if overwrite, to.isFile, isFile {
             try FileManager.default.removeItem(at: to.url)
         }
+    #if os(Linux) && !swift(>=5.1) // check if fixed
+        if !overwrite, to.isFile {
+            throw CocoaError.error(.fileWriteFileExists)
+        }
+    #endif
         try FileManager.default.copyItem(atPath: string, toPath: to.string)
         return to
     }
@@ -38,7 +46,8 @@ public extension Path {
          // Create ~/.local/bin, copy `ls` there and make the new copy executable
          try Path.root.join("bin/ls").copy(into: Path.home.join(".local/bin").mkdir(.p)).chmod(0o500)
 
-     If the destination does not exist, this function creates the directory first.
+     If the destination does not exist, this function creates the directory
+     (including intermediary directories if necessary) first.
 
      - Parameter into: Destination directory
      - Parameter overwrite: If true overwrites any file that already exists at `into`.
@@ -48,25 +57,21 @@ public extension Path {
       `self` because even though *Path.swift’s* policy is to noop if the desired
        end result preexists, checking for this condition is too expensive a
        trade-off.
-     - SeeAlso: `copy(into:overwrite:)`
+     - SeeAlso: `copy(to:overwrite:)`
      */
     @discardableResult
     func copy(into: Path, overwrite: Bool = false) throws -> Path {
         if !into.exists {
-            try FileManager.default.createDirectory(at: url, withIntermediateDirectories: true)
+            try into.mkdir(.p)
         }
         let rv = into/basename()
         if overwrite, rv.isFile {
             try rv.delete()
         }
-    #if os(Linux)
+    #if os(Linux) && !swift(>=5.1) // check if fixed
-    #if swift(>=5.1)
-        // check if fixed
-    #else
         if !overwrite, rv.isFile {
             throw CocoaError.error(.fileWriteFileExists)
         }
-    #endif
     #endif
         try FileManager.default.copyItem(at: url, to: rv.url)
         return rv
@@ -86,7 +91,7 @@ public extension Path {
        `self` because even though *Path.swift’s* policy is to noop if the desired
        end result preexists, checking for this condition is too expensive a
        trade-off.
-     - SeeAlso: move(into:overwrite:)
+     - SeeAlso: `move(into:overwrite:)`
      */
     @discardableResult
     func move(to: Path, overwrite: Bool = false) throws -> Path {
@@ -103,13 +108,14 @@ public extension Path {
          try Path.root.join("bar").move(into: .home)
          // => "/Users/mxcl/bar"
 
-     If the destination does not exist, this function creates the directory first.
+     If the destination does not exist, this function creates the directory
+     (including intermediary directories if necessary) first.
 
      - Parameter into: Destination directory
      - Parameter overwrite: If true *overwrites* any file that already exists at `into`.
      - Note: `throws` if `into` is a file.
      - Returns: The `Path` of destination filename.
-     - SeeAlso: move(into:overwrite:)
+     - SeeAlso: `move(to:overwrite:)`
      */
     @discardableResult
     func move(into: Path, overwrite: Bool = false) throws -> Path {
@@ -142,13 +148,26 @@ public extension Path {
     }
 
     /**
-     Creates an empty file at this path.
+     Creates an empty file at this path or if the file exists, updates its modification time.
      - Returns: `self` to allow chaining.
      */
     @inlinable
     @discardableResult
     func touch() throws -> Path {
-        return try "".write(to: self)
+        if !exists {
+            guard FileManager.default.createFile(atPath: string, contents: nil) else {
+                throw CocoaError.error(.fileWriteUnknown)
+            }
+        } else {
+        #if os(Linux)
+            let fd = open(string, O_WRONLY)
+            defer { close(fd) }
+            futimens(fd, nil)
+        #else
+            try FileManager.default.setAttributes([.modificationDate: Date()], ofItemAtPath: string)
+        #endif
+        }
+        return self
     }
 
     /**
@@ -192,6 +211,32 @@ public extension Path {
         try FileManager.default.moveItem(atPath: string, toPath: newpath.string)
         return newpath
     }
+
+    /**
+     Creates a symlink of this file at `as`.
+     - Note: If `self` does not exist, is **not** an error.
+     */
+    @discardableResult
+    func symlink(as: Path) throws -> Path {
+        try FileManager.default.createSymbolicLink(atPath: `as`.string, withDestinationPath: string)
+        return `as`
+    }
+
+    /**
+     Creates a symlink of this file with the same filename in the `into` directory.
+     - Note: If into does not exist, creates the directory with intermediate directories if necessary.
+     */
+    @discardableResult
+    func symlink(into dir: Path) throws -> Path {
+        if !dir.exists {
+            try dir.mkdir(.p)
+        } else if !dir.isDirectory {
+            throw CocoaError.error(.fileWriteFileExists)
+        }
+        let dst = dir/basename()
+        try FileManager.default.createSymbolicLink(atPath: dst.string, withDestinationPath: string)
+        return dst
+    }
 }
 
 /// Options for `Path.mkdir(_:)`

Sources/Path+StringConvertibles.swift

@@ -1,5 +1,3 @@
-import class Foundation.NSString
-
 extension Path: CustomStringConvertible {    
     /// Returns `Path.string`
     public var description: String {

Sources/Path->Bool.swift

@@ -2,7 +2,7 @@ import Foundation
 #if os(Linux)
 import func Glibc.access
 #else
-import func Darwin.access
+import Darwin
 #endif
 
 public extension Path {
@@ -55,4 +55,11 @@ public extension Path {
             return false
         }
     }
+
+    /// Returns `true` if the file is a symbolic-link (symlink).
+    var isSymlink: Bool {
+        var sbuf = stat()
+        lstat(string, &sbuf)
+        return (sbuf.st_mode & S_IFMT) == S_IFLNK 
+    }
 }

Sources/Path.swift

@@ -1,4 +1,11 @@
 import Foundation
+#if !os(Linux)
+import func Darwin.realpath
+let _realpath = Darwin.realpath
+#else
+import func Glibc.realpath
+let _realpath = Glibc.realpath
+#endif
 
 /**
  A `Path` represents an absolute path on a filesystem.
@@ -32,19 +39,97 @@ import Foundation
 public struct Path: Equatable, Hashable, Comparable {
 
     init(string: String) {
+        assert(string.first == "/")
+        assert(string.last != "/" || string == "/")
+        assert(string.split(separator: "/").contains("..") == false)
         self.string = string
     }
 
-    /// Returns `nil` unless fed an absolute path.
+    /**
+     Creates a new absolute, standardized path.
+     - Note: Resolves any .. or . components.
+     - Note: Removes multiple subsequent and trailing occurences of `/`.
+     - Note: Does *not* resolve any symlinks.
+     - Note: On macOS, removes an initial component of “/private/var/automount”, “/var/automount”, or “/private” from the path, if the result still indicates an existing file or directory (checked by consulting the file system).
+     - Returns: The path or `nil` if fed a relative path or a `~foo` string where there is no user `foo`.
+     */
     public init?(_ description: String) {
-        guard description.starts(with: "/") || description.starts(with: "~/") else { return nil }
+        var pathComponents = description.split(separator: "/")
-        self.init(string: (description as NSString).standardizingPath)
+        switch description.first {
+        case "/":
+            break
+        case "~":
+            if description == "~" {
+                self = Path.home
+                return
+            }
+            let tilded: String
+            if description.hasPrefix("~/") {
+                tilded = Path.home.string
+            } else {
+                let username = String(pathComponents[0].dropFirst())
+            #if os(macOS) || os(Linux)
+                if #available(OSX 10.12, *) {
+                    guard let url = FileManager.default.homeDirectory(forUser: username) else { return nil }
+                    assert(url.scheme == "file")
+                    tilded = url.path
+                } else {
+                    guard let dir = NSHomeDirectoryForUser(username) else { return nil }
+                    tilded = dir
+                }
+            #else
+                return nil  // there are no usernames on iOS, etc.
+            #endif
+            }
+            pathComponents.remove(at: 0)
+            pathComponents.insert(contentsOf: tilded.split(separator: "/"), at: 0)
+        default:
+            return nil
+        }
+
+    #if os(macOS)
+        func ifExists(withPrefix prefix: String, removeFirst n: Int) {
+            assert(prefix.split(separator: "/").count == n)
+
+            if description.hasPrefix(prefix), FileManager.default.fileExists(atPath: description) {
+                pathComponents.removeFirst(n)
+            }
+        }
+
+        ifExists(withPrefix: "/private/var/automount", removeFirst: 3)
+        ifExists(withPrefix: "/var/automount", removeFirst: 2)
+        ifExists(withPrefix: "/private", removeFirst: 1)
+    #endif
+
+        self.string = join_(prefix: "/", pathComponents: pathComponents)
+    }
+
+    /**
+     Creates a new absolute, standardized path from the provided file-scheme URL.
+     - Note: If the URL is not a file URL, returns `nil`.
+    */
+    public init?(url: URL) {
+        guard url.scheme == "file" else { return nil }
+        self.init(url.path)
+        //NOTE: URL cannot be a file-reference url, unlike NSURL, so this always works
+    }
+
+    /**
+     Creates a new absolute, standardized path from the provided file-scheme URL.
+     - Note: If the URL is not a file URL, returns `nil`.
+     - Note: If the URL is a file reference URL, converts it to a POSIX path first.
+    */
+    public init?(url: NSURL) {
+        guard url.scheme == "file", let path = url.path else { return nil }
+        self.init(string: path)
+        // ^^ works even if the url is a file-reference url
     }
 
     /// :nodoc:
-    public subscript(dynamicMember pathComponent: String) -> Path {
+    public subscript(dynamicMember addendum: String) -> Path {
-        let str = (string as NSString).appendingPathComponent(pathComponent)
+        //NOTE it’s possible for the string to be anything if we are invoked via
-        return Path(string: str)
+        // explicit subscript thus we use our fully sanitized `join` function
+        return Path(string: join_(prefix: string, appending: addendum))
     }
 
 //MARK: Properties
@@ -57,6 +142,21 @@ public struct Path: Equatable, Hashable, Comparable {
         return URL(fileURLWithPath: string)
     }
 
+    /**
+     Returns a file-reference URL.
+     - Note: Only NSURL can be a file-reference-URL, hence we return NSURL.
+     - SeeAlso: https://developer.apple.com/documentation/foundation/nsurl/1408631-filereferenceurl
+     - Important: On Linux returns an file scheme NSURL for this path string.
+     */
+    public var fileReferenceURL: NSURL? {
+    #if !os(Linux)
+        // https://bugs.swift.org/browse/SR-2728
+        return (url as NSURL).perform(#selector(NSURL.fileReferenceURL))?.takeUnretainedValue() as? NSURL
+    #else
+        return NSURL(fileURLWithPath: string)
+    #endif
+    }
+
     /**
      Returns the parent directory for this path.
 
@@ -66,23 +166,49 @@ public struct Path: Equatable, Hashable, Comparable {
      - Note: always returns a valid path, `Path.root.parent` *is* `Path.root`.
      */
     public var parent: Path {
-        return Path(string: (string as NSString).deletingLastPathComponent)
+        let index = string.lastIndex(of: "/")!
+        let substr = string[string.indices.startIndex..<index]
+        return Path(string: String(substr))
     }
 
     /**
      Returns the filename extension of this path.
-     - Remark: Implemented via `NSString.pathExtension`.
+     - Remark: If there is no extension returns "".
+     - Remark: If the filename ends with any number of ".", returns "".
      - Note: We special case eg. `foo.tar.gz`.
      */
     @inlinable
     public var `extension`: String {
-        if string.hasSuffix(".tar.gz") {
+        //FIXME efficiency
+        switch true {
+        case string.hasSuffix(".tar.gz"):
             return "tar.gz"
-        } else {
+        case string.hasSuffix(".tar.bz"):
-            return (string as NSString).pathExtension
+            return "tar.bz"
+        case string.hasSuffix(".tar.bz2"):
+            return "tar.bz2"
+        case string.hasSuffix(".tar.xz"):
+            return "tar.xz"
+        default:
+            let slash = string.lastIndex(of: "/")!
+            if let dot = string.lastIndex(of: "."), slash < dot {
+                let foo = string.index(after: dot)
+                return String(string[foo...])
+            } else {
+                return ""
+            }
         }
     }
 
+    /**
+     Splits the string representation on the directory separator.
+     - Important: The first element is always "/" to be consistent with `NSString.pathComponents`.
+    */
+    @inlinable
+    public var components: [String] {
+        return ["/"] + string.split(separator: "/").map(String.init)
+    }
+
 //MARK: Pathing
 
     /**
@@ -93,14 +219,15 @@ public struct Path: Equatable, Hashable, Comparable {
          Path.root.join("a").join("b")   // => /a/b
          Path.root.join("a").join("/b")  // => /a/b
 
+     - Note: `..` and `.` components are interpreted.
+     - Note: pathComponent *may* be multiple components.
+     - Note: symlinks are *not* resolved.
      - Parameter pathComponent: The string to join with this path.
      - Returns: A new joined path.
      - SeeAlso: `Path./(_:_:)`
      */
-    public func join<S>(_ pathComponent: S) -> Path where S: StringProtocol {
+    public func join<S>(_ addendum: S) -> Path where S: StringProtocol {
-        //TODO standardizingPath does more than we want really (eg tilde expansion)
+        return Path(string: join_(prefix: string, appending: addendum))
-        let str = (string as NSString).appendingPathComponent(String(pathComponent))
-        return Path(string: (str as NSString).standardizingPath)
     }
 
     /**
@@ -111,6 +238,9 @@ public struct Path: Equatable, Hashable, Comparable {
          Path.root/"a"/"b"   // => /a/b
          Path.root/"a"/"/b"  // => /a/b
 
+     - Note: `..` and `.` components are interpreted.
+     - Note: pathComponent *may* be multiple components.
+     - Note: symlinks are *not* resolved.
      - Parameter lhs: The base path to join with `rhs`.
      - Parameter rhs: The string to join with this `lhs`.
      - Returns: A new joined path.
@@ -168,17 +298,71 @@ public struct Path: Equatable, Hashable, Comparable {
      - Parameter dropExtension: If `true` returns the basename without its file extension.
      */
     public func basename(dropExtension: Bool = false) -> String {
-        let str = string as NSString
+        var lastPathComponent: Substring {
-        if !dropExtension {
+            let slash = string.lastIndex(of: "/")!
-            return str.lastPathComponent
+            let index = string.index(after: slash)
-        } else {
+            return string[index...]
-            let ext = str.pathExtension
+        }
-            if !ext.isEmpty {
+        var go: Substring {
-                return String(str.lastPathComponent.dropLast(ext.count + 1))
+            if !dropExtension {
+                return lastPathComponent
             } else {
-                return str.lastPathComponent
+                let ext = self.extension
+                if !ext.isEmpty {
+                    return lastPathComponent.dropLast(ext.count + 1)
+                } else {
+                    return lastPathComponent
+                }
             }
         }
+        return String(go)
+    }
+
+    /**
+     If the path represents an actual entry that is a symlink, returns the symlink’s
+     absolute destination.
+
+     - Important: This is not exhaustive, the resulting path may still contain
+     symlink.
+     - Important: The path will only be different if the last path component is a
+     symlink, any symlinks in prior components are not resolved.
+     - Note: If file exists but isn’t a symlink, returns `self`.
+     - Note: If symlink destination does not exist, is **not** an error.
+     */
+    public func readlink() throws -> Path {
+        do {
+            let rv = try FileManager.default.destinationOfSymbolicLink(atPath: string)
+            return Path(rv) ?? parent/rv
+        } catch CocoaError.fileReadUnknown {
+            // file is not symlink, return `self`
+            assert(exists)
+            return self
+        } catch {
+        #if os(Linux)
+            // ugh: Swift on Linux
+            let nsError = error as NSError
+            if nsError.domain == NSCocoaErrorDomain, nsError.code == CocoaError.fileReadUnknown.rawValue, exists {
+                return self
+            }
+        #endif
+            throw error
+        }
+    }
+
+    /// Recursively resolves symlinks in this path.
+    public func realpath() throws -> Path {
+        guard let rv = _realpath(string, nil) else { throw CocoaError.error(.fileNoSuchFile) }
+        defer { free(rv) }
+        guard let rvv = String(validatingUTF8: rv) else { throw CocoaError.error(.fileReadUnknownStringEncoding) }
+
+        // “Removing an initial component of “/private/var/automount”, “/var/automount”,
+        // or “/private” from the path, if the result still indicates an existing file or
+        // directory (checked by consulting the file system).”
+        // ^^ we do this to not conflict with the results that other Apple APIs give
+        // which is necessary if we are to have equality checks work reliably
+        let rvvv = (rvv as NSString).standardizingPath
+
+        return Path(string: rvvv)
     }
 
     /// Returns the locale-aware sort order for the two paths.
@@ -188,3 +372,38 @@ public struct Path: Equatable, Hashable, Comparable {
         return lhs.string.compare(rhs.string, locale: .current) == .orderedAscending
     }
 }
+
+@inline(__always)
+private func join_<S>(prefix: String, appending: S) -> String where S: StringProtocol {
+    return join_(prefix: prefix, pathComponents: appending.split(separator: "/"))
+}
+
+private func join_<S>(prefix: String, pathComponents: S) -> String where S: Sequence, S.Element: StringProtocol {
+    assert(prefix.first == "/")
+
+    var rv = prefix
+    for component in pathComponents {
+
+        assert(!component.contains("/"))
+
+        switch component {
+        case "..":
+            let start = rv.indices.startIndex
+            let index = rv.lastIndex(of: "/")!
+            if start == index {
+                rv = "/"
+            } else {
+                rv = String(rv[start..<index])
+            }
+        case ".":
+            break
+        default:
+            if rv == "/" {
+                rv = "/\(component)"
+            } else {
+                rv = "\(rv)/\(component)"
+            }
+        }
+    }
+    return rv
+}

Tests/PathTests/PathTests.swift

@@ -1,5 +1,5 @@
+@testable import Path
 import XCTest
-import Path
 
 class PathTests: XCTestCase {
     func testConcatenation() {
@@ -9,6 +9,10 @@ class PathTests: XCTestCase {
         XCTAssertEqual((Path.root/"///bar").string, "/bar")
         XCTAssertEqual((Path.root/"foo///bar////").string, "/foo/bar")
         XCTAssertEqual((Path.root/"foo"/"/bar").string, "/foo/bar")
+
+        XCTAssertEqual(Path.root.foo.bar.join(".."), Path.root.foo)
+        XCTAssertEqual(Path.root.foo.bar.join("."), Path.root.foo.bar)
+        XCTAssertEqual(Path.root.foo.bar.join("../baz"), Path.root.foo.baz)
     }
 
     func testEnumeration() throws {
@@ -76,15 +80,19 @@ class PathTests: XCTestCase {
     }
 
     func testExtension() {
-        XCTAssertEqual(Path.root.join("a.swift").extension, "swift")
+        for prefix in [Path.root, Path.root.foo, Path.root.foo.bar] {
-        XCTAssertEqual(Path.root.join("a").extension, "")
+            XCTAssertEqual(prefix.join("a.swift").extension, "swift")
-        XCTAssertEqual(Path.root.join("a.").extension, "")
+            XCTAssertEqual(prefix.join("a").extension, "")
-        XCTAssertEqual(Path.root.join("a..").extension, "")
+            XCTAssertEqual(prefix.join("a.").extension, "")
-        XCTAssertEqual(Path.root.join("a..swift").extension, "swift")
+            XCTAssertEqual(prefix.join("a..").extension, "")
-        XCTAssertEqual(Path.root.join("a..swift.").extension, "")
+            XCTAssertEqual(prefix.join("a..swift").extension, "swift")
-        XCTAssertEqual(Path.root.join("a.tar.gz").extension, "tar.gz")
+            XCTAssertEqual(prefix.join("a..swift.").extension, "")
-        XCTAssertEqual(Path.root.join("a..tar.gz").extension, "tar.gz")
+            XCTAssertEqual(prefix.join("a.tar.gz").extension, "tar.gz")
-        XCTAssertEqual(Path.root.join("a..tar..gz").extension, "gz")
+            XCTAssertEqual(prefix.join("a.tar.bz2").extension, "tar.bz2")
+            XCTAssertEqual(prefix.join("a.tar.xz").extension, "tar.xz")
+            XCTAssertEqual(prefix.join("a..tar.bz").extension, "tar.bz")
+            XCTAssertEqual(prefix.join("a..tar..xz").extension, "xz")
+        }
     }
 
     func testMktemp() throws {
@@ -107,28 +115,32 @@ class PathTests: XCTestCase {
     }
 
     func testBasename() {
-        XCTAssertEqual(Path.root.join("foo.bar").basename(dropExtension: true), "foo")
+        for prefix in [Path.root, Path.root.foo, Path.root.foo.bar] {
-        XCTAssertEqual(Path.root.join("foo").basename(dropExtension: true), "foo")
+            XCTAssertEqual(prefix.join("foo.bar").basename(dropExtension: true), "foo")
-        XCTAssertEqual(Path.root.join("foo.").basename(dropExtension: true), "foo.")
+            XCTAssertEqual(prefix.join("foo").basename(dropExtension: true), "foo")
-        XCTAssertEqual(Path.root.join("foo.bar.baz").basename(dropExtension: true), "foo.bar")
+            XCTAssertEqual(prefix.join("foo.").basename(dropExtension: true), "foo.")
+            XCTAssertEqual(prefix.join("foo.bar.baz").basename(dropExtension: true), "foo.bar")
+        }
     }
 
     func testCodable() throws {
-        let input = [Path.root/"bar"]
+        let input = [Path.root.foo, Path.root.foo.bar, Path.root]
         XCTAssertEqual(try JSONDecoder().decode([Path].self, from: try JSONEncoder().encode(input)), input)
     }
 
     func testRelativePathCodable() throws {
-        let root = Path.root/"bar"
+        let root = Path.root.foo
         let input = [
-            root/"foo"
+            Path.root,
+            root,
+            root.bar
         ]
 
         let encoder = JSONEncoder()
         encoder.userInfo[.relativePath] = root
         let data = try encoder.encode(input)
 
-        XCTAssertEqual(try JSONSerialization.jsonObject(with: data) as? [String], ["foo"])
+        XCTAssertEqual(try JSONSerialization.jsonObject(with: data) as? [String], ["..", "", "bar"])
 
         let decoder = JSONDecoder()
         XCTAssertThrowsError(try decoder.decode([Path].self, from: data))
@@ -148,8 +160,16 @@ class PathTests: XCTestCase {
         XCTAssertEqual(prefix/b/c, Path("/Users/mxcl/b/c"))
         XCTAssertEqual(Path.root/"~b", Path("/~b"))
         XCTAssertEqual(Path.root/"~/b", Path("/~/b"))
+
         XCTAssertEqual(Path("~/foo"), Path.home/"foo")
+        XCTAssertEqual(Path("~"), Path.home)
+        XCTAssertEqual(Path("~/"), Path.home)
+        XCTAssertEqual(Path("~///"), Path.home)
+        XCTAssertEqual(Path("/~///"), Path.root/"~")
         XCTAssertNil(Path("~foo"))
+        XCTAssertNil(Path("~foo/bar"))
+
+        XCTAssertEqual(Path("~\(NSUserName())"), Path.home)
 
         XCTAssertEqual(Path.root/"a/foo"/"../bar", Path.root/"a/bar")
         XCTAssertEqual(Path.root/"a/foo"/"/../bar", Path.root/"a/bar")
@@ -162,6 +182,9 @@ class PathTests: XCTestCase {
 
         let a = Path.home.foo
         XCTAssertEqual(a.Documents, Path.home/"foo/Documents")
+
+        // verify use of the dynamic-member-subscript works according to our rules
+        XCTAssertEqual(Path.home[dynamicMember: "../~foo"].string, "\(Path.home.parent.string)/~foo")
     }
 
     func testCopyTo() throws {
@@ -169,6 +192,16 @@ class PathTests: XCTestCase {
             try root.foo.touch().copy(to: root.bar)
             XCTAssert(root.foo.isFile)
             XCTAssert(root.bar.isFile)
+            XCTAssertThrowsError(try root.foo.copy(to: root.bar))
+            try root.foo.copy(to: root.bar, overwrite: true)
+        }
+
+        // test copy errors if directory exists at destination, even with overwrite
+        try Path.mktemp { root in
+            try root.foo.touch()
+            XCTAssert(root.foo.isFile)
+            XCTAssertThrowsError(try root.foo.copy(to: root.bar.mkdir()))
+            XCTAssertThrowsError(try root.foo.copy(to: root.bar, overwrite: true))
         }
     }
 
@@ -182,14 +215,33 @@ class PathTests: XCTestCase {
                 XCTAssertTrue(bar1.exists)
                 XCTAssertTrue(bar2.exists)
             }
+
+            // test creates intermediary directories
+            try bar1.copy(into: root1.create.directories)
+
+            // test doesn’t replace file if “copy into” a file
+            let d = try root1.fuz.touch()
+            XCTAssertThrowsError(try root1.baz.touch().copy(into: d))
+            XCTAssert(d.isFile)
+            XCTAssert(root1.baz.isFile)
         }
     }
 
     func testMoveTo() throws {
+        try Path.mktemp { tmpdir in
+            try tmpdir.foo.touch().move(to: tmpdir.bar)
+            XCTAssertFalse(tmpdir.foo.exists)
+            XCTAssert(tmpdir.bar.isFile)
+            XCTAssertThrowsError(try tmpdir.foo.touch().move(to: tmpdir.bar))
+            try tmpdir.foo.move(to: tmpdir.bar, overwrite: true)
+        }
+
+        // test move errors if directory exists at destination, even with overwrite
         try Path.mktemp { root in
-            try root.foo.touch().move(to: root.bar)
+            try root.foo.touch()
-            XCTAssertFalse(root.foo.exists)
+            XCTAssert(root.foo.isFile)
-            XCTAssert(root.bar.isFile)
+            XCTAssertThrowsError(try root.foo.move(to: root.bar.mkdir()))
+            XCTAssertThrowsError(try root.foo.move(to: root.bar, overwrite: true))
         }
     }
 
@@ -203,6 +255,17 @@ class PathTests: XCTestCase {
                 XCTAssertFalse(bar1.exists)
                 XCTAssertTrue(bar2.exists)
             }
+
+            // test creates intermediary directories
+            try root1.baz.touch().move(into: root1.create.directories)
+            XCTAssertFalse(root1.baz.exists)
+            XCTAssert(root1.create.directories.baz.isFile)
+
+            // test doesn’t replace file if “move into” a file
+            let d = try root1.fuz.touch()
+            XCTAssertThrowsError(try root1.baz.touch().move(into: d))
+            XCTAssert(d.isFile)
+            XCTAssert(root1.baz.isFile)
         }
     }
 
@@ -225,10 +288,14 @@ class PathTests: XCTestCase {
         XCTAssertEqual(Path.root.string, "/")
         XCTAssertEqual(Path.home.string, NSHomeDirectory())
         XCTAssertEqual(Path.documents.string, NSHomeDirectory() + "/Documents")
-    #if os(macOS)
+    #if !os(Linux)
         XCTAssertEqual(Path.caches.string, NSHomeDirectory() + "/Library/Caches")
         XCTAssertEqual(Path.cwd.string, FileManager.default.currentDirectoryPath)
         XCTAssertEqual(Path.applicationSupport.string, NSHomeDirectory() + "/Library/Application Support")
+
+        _ = defaultUrl(for: .documentDirectory)
+        _ = defaultUrl(for: .cachesDirectory)
+        _ = defaultUrl(for: .applicationSupportDirectory)
     #endif
     }
 
@@ -298,6 +365,9 @@ class PathTests: XCTestCase {
             let now2 = Date().timeIntervalSince1970.rounded(.down)
             XCTAssertNotEqual(now1, now2)
             XCTAssertEqual(foo.mtime?.timeIntervalSince1970.rounded(.down), now2)  //FIXME flakey
+
+            XCTAssertNil(tmpdir.void.mtime)
+            XCTAssertNil(tmpdir.void.ctime)
         }
     }
 
@@ -325,23 +395,37 @@ class PathTests: XCTestCase {
         XCTAssertThrowsError(try JSONDecoder().decode([Path].self, from: data))
     }
 
-    func testBundleExtensions() {
+    func testBundleExtensions() throws {
-        XCTAssertTrue(Bundle.main.path.isDirectory)
-        XCTAssertTrue(Bundle.main.resources.isDirectory)
-
-        // don’t exist in tests
-        _ = Bundle.main.path(forResource: "foo", ofType: "bar")
-        _ = Bundle.main.sharedFrameworks
-    }
-
-    func testDataExentsions() throws {
-        let data = try Data(contentsOf: Path(#file)!)
         try Path.mktemp { tmpdir in
-            _ = try data.write(to: tmpdir.foo)
+            let bndl = Bundle(path: tmpdir.string)!
+            XCTAssertEqual(bndl.path, tmpdir)
+            XCTAssertEqual(bndl.sharedFrameworks, tmpdir.SharedFrameworks)
+            XCTAssertEqual(bndl.privateFrameworks, tmpdir.Frameworks)
+            XCTAssertEqual(bndl.resources, tmpdir)
+            XCTAssertNil(bndl.path(forResource: "foo", ofType: "bar"))
+
+        #if os(macOS)
+            XCTAssertEqual(bndl.defaultSharedFrameworksPath, tmpdir.Contents.Frameworks)
+            XCTAssertEqual(bndl.defaultResourcesPath, tmpdir.Contents.Resources)
+        #elseif os(tvOS) || os(iOS)
+            XCTAssertEqual(bndl.defaultSharedFrameworksPath, tmpdir.Frameworks)
+            XCTAssertEqual(bndl.defaultResourcesPath, tmpdir)
+        #else
+            XCTAssertEqual(bndl.defaultSharedFrameworksPath, tmpdir.lib)
+            XCTAssertEqual(bndl.defaultResourcesPath, tmpdir.share)
+        #endif
         }
     }
 
-    func testStringExentsions() throws {
+    func testDataExtensions() throws {
+        let data = try Data(contentsOf: Path(#file)!)
+        try Path.mktemp { tmpdir in
+            _ = try data.write(to: tmpdir.foo)
+            _ = try data.write(to: tmpdir.foo, atomically: true)
+        }
+    }
+
+    func testStringExtensions() throws {
         let string = try String(contentsOf: Path(#file)!)
         try Path.mktemp { tmpdir in
             _ = try string.write(to: tmpdir.foo)
@@ -353,4 +437,160 @@ class PathTests: XCTestCase {
         _ = try FileHandle(forWritingAt: Path(#file)!)
         _ = try FileHandle(forUpdatingAt: Path(#file)!)
     }
+
+    func testSort() {
+        XCTAssertEqual([Path.root.a, Path.root.c, Path.root.b].sorted(), [Path.root.a, Path.root.b, Path.root.c])
+    }
+
+    func testLock() throws {
+    #if !os(Linux)
+        try Path.mktemp { tmpdir in
+            let bar = try tmpdir.bar.touch()
+            try bar.lock()
+            XCTAssertThrowsError(try bar.touch())
+            try bar.unlock()
+            try bar.touch()
+
+            // a non existant file is already “unlocked”
+            try tmpdir.nonExit.unlock()
+        }
+    #endif
+    }
+
+    func testTouchThrowsIfCannotWrite() throws {
+        try Path.mktemp { tmpdir in
+            try tmpdir.chmod(0o000)
+            XCTAssertThrowsError(try tmpdir.bar.touch())
+        }
+    }
+
+    func testSymlinkFunctions() throws {
+        try Path.mktemp { tmpdir in
+            let foo = try tmpdir.foo.touch()
+            let bar = try foo.symlink(as: tmpdir.bar)
+            XCTAssert(bar.isSymlink)
+            XCTAssertEqual(try bar.readlink(), foo)
+        }
+
+        try Path.mktemp { tmpdir in
+            let foo1 = try tmpdir.foo.touch()
+            let foo2 = try foo1.symlink(into: tmpdir.bar)
+            XCTAssert(foo2.isSymlink)
+            XCTAssert(tmpdir.bar.isDirectory)
+            XCTAssertEqual(try foo2.readlink(), foo1)
+
+            // cannot symlink into when `into` is an existing entry that is not a directory
+            let baz = try tmpdir.baz.touch()
+            XCTAssertThrowsError(try foo1.symlink(into: baz))
+        }
+
+        try Path.mktemp { tmpdir in
+            let foo = try tmpdir.foo.touch()
+            let bar = try tmpdir.bar.mkdir()
+            XCTAssertThrowsError(try foo.symlink(as: bar))
+            XCTAssert(try foo.symlink(as: bar.foo).isSymlink)
+        }
+    }
+
+    func testReadlinkOnRelativeSymlink() throws {
+        //TODO how to test on iOS etc.?
+    #if os(macOS) || os(Linux)
+        try Path.mktemp { tmpdir in
+            let foo = try tmpdir.foo.mkdir()
+            let bar = try tmpdir.bar.touch()
+
+            let task = Process()
+            task.currentDirectoryPath = foo.string
+            task.launchPath = "/bin/ln"
+            task.arguments = ["-s", "../bar", "baz"]
+            task.launch()
+            task.waitUntilExit()
+            XCTAssertEqual(task.terminationStatus, 0)
+
+            XCTAssert(tmpdir.foo.baz.isSymlink)
+
+            XCTAssertEqual(try FileManager.default.destinationOfSymbolicLink(atPath: tmpdir.foo.baz.string), "../bar")
+
+            XCTAssertEqual(try tmpdir.foo.baz.readlink(), bar)
+        }
+    #endif
+    }
+
+    func testReadlinkOnFileReturnsSelf() throws {
+        try Path.mktemp { tmpdir in
+            XCTAssertEqual(try tmpdir.foo.touch(), tmpdir.foo)
+            XCTAssertEqual(try tmpdir.foo.readlink(), tmpdir.foo)
+        }
+    }
+
+    func testReadlinkOnNonExistantFileThrows() throws {
+        try Path.mktemp { tmpdir in
+            XCTAssertThrowsError(try tmpdir.bar.readlink())
+        }
+    }
+
+    func testReadlinkWhereLinkDestinationDoesNotExist() throws {
+        try Path.mktemp { tmpdir in
+            let bar = try tmpdir.foo.symlink(as: tmpdir.bar)
+            XCTAssertEqual(try bar.readlink(), tmpdir.foo)
+        }
+    }
+
+    func testNoUndesiredSymlinkResolution() throws {
+
+        // this test because NSString.standardizingPath will resolve symlinks
+        // if the path you give it contains .. and the result is an actual entry
+
+        try Path.mktemp { tmpdir in
+            let foo = try tmpdir.foo.mkdir()
+            try foo.bar.mkdir().fuz.touch()
+            let baz = try foo.symlink(as: tmpdir.baz)
+            XCTAssert(baz.isSymlink)
+            XCTAssert(baz.bar.isDirectory)
+            XCTAssertEqual(baz.bar.join("..").string, "\(tmpdir)/baz")
+
+            XCTAssertEqual(Path("\(tmpdir)/baz/bar/..")?.string, "\(tmpdir)/baz")
+        }
+    }
+
+    func testRealpath() throws {
+        try Path.mktemp { tmpdir in
+            let b = try tmpdir.a.b.mkdir(.p)
+            let c = try tmpdir.a.c.touch()
+            let e = try c.symlink(as: b.e)
+            let f = try e.symlink(as: tmpdir.f)
+            XCTAssertEqual(try f.readlink(), e)
+            XCTAssertEqual(try f.realpath(), c)
+        }
+
+        try Path.mktemp { tmpdir in
+            XCTAssertThrowsError(try tmpdir.foo.realpath())
+        }
+    }
+
+    func testFileReference() throws {
+        let ref = Path.home.fileReferenceURL
+    #if !os(Linux)
+        XCTAssertTrue(ref?.isFileReferenceURL() ?? false)
+    #endif
+        XCTAssertEqual(ref?.path, Path.home.string)
+    }
+
+    func testURLInitializer() throws {
+        XCTAssertEqual(Path(url: Path.home.url), Path.home)
+        XCTAssertEqual(Path.home.fileReferenceURL.flatMap(Path.init), Path.home)
+        XCTAssertNil(Path(url: URL(string: "https://foo.com")!))
+        XCTAssertNil(Path(url: NSURL(string: "https://foo.com")!))
+    }
+
+    func testInitializerForRelativePath() throws {
+        XCTAssertNil(Path("foo"))
+        XCTAssertNil(Path("../foo"))
+        XCTAssertNil(Path("./foo"))
+    }
+
+    func testPathComponents() throws {
+        XCTAssertEqual(Path.root.foo.bar.components, ["/", "foo", "bar"])
+        XCTAssertEqual(Path.root.components, ["/"])
+    }
 }

Tests/PathTests/XCTestManifests.swift

@@ -9,7 +9,7 @@ extension PathTests {
         ("testConcatenation", testConcatenation),
         ("testCopyInto", testCopyInto),
         ("testCopyTo", testCopyTo),
-        ("testDataExentsions", testDataExentsions),
+        ("testDataExtensions", testDataExtensions),
         ("testDelete", testDelete),
         ("testDynamicMember", testDynamicMember),
         ("testEnumeration", testEnumeration),
@@ -17,20 +17,34 @@ extension PathTests {
         ("testExists", testExists),
         ("testExtension", testExtension),
         ("testFileHandleExtensions", testFileHandleExtensions),
+        ("testFileReference", testFileReference),
         ("testFilesystemAttributes", testFilesystemAttributes),
+        ("testInitializerForRelativePath", testInitializerForRelativePath),
         ("testIsDirectory", testIsDirectory),
         ("testJoin", testJoin),
+        ("testLock", testLock),
         ("testMkpathIfExists", testMkpathIfExists),
         ("testMktemp", testMktemp),
         ("testMoveInto", testMoveInto),
         ("testMoveTo", testMoveTo),
+        ("testNoUndesiredSymlinkResolution", testNoUndesiredSymlinkResolution),
+        ("testPathComponents", testPathComponents),
+        ("testReadlinkOnFileReturnsSelf", testReadlinkOnFileReturnsSelf),
+        ("testReadlinkOnNonExistantFileThrows", testReadlinkOnNonExistantFileThrows),
+        ("testReadlinkOnRelativeSymlink", testReadlinkOnRelativeSymlink),
+        ("testReadlinkWhereLinkDestinationDoesNotExist", testReadlinkWhereLinkDestinationDoesNotExist),
+        ("testRealpath", testRealpath),
         ("testRelativeCodable", testRelativeCodable),
         ("testRelativePathCodable", testRelativePathCodable),
         ("testRelativeTo", testRelativeTo),
         ("testRename", testRename),
+        ("testSort", testSort),
         ("testStringConvertibles", testStringConvertibles),
-        ("testStringExentsions", testStringExentsions),
+        ("testStringExtensions", testStringExtensions),
+        ("testSymlinkFunctions", testSymlinkFunctions),
         ("testTimes", testTimes),
+        ("testTouchThrowsIfCannotWrite", testTouchThrowsIfCannotWrite),
+        ("testURLInitializer", testURLInitializer),
     ]
 }