0e061f9cc8
`delete()` and other functions would check `exists` to do certain behaviors, but `exists` will validate a symlink if the entry is a symlink, thus instead we check if the path is an actual entry now instead.
345 lines
10 KiB
Markdown
345 lines
10 KiB
Markdown
# Path.swift ![badge-platforms][] ![badge-languages][] [![badge-ci][]][travis] [![badge-jazzy][]][docs] [![badge-codecov][]][codecov] [![badge-version][]][cocoapods]
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A file-system pathing library focused on developer experience and robust end
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results.
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```swift
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import Path
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// convenient static members
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let home = Path.home
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// pleasant joining syntax
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let docs = Path.home/"Documents"
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// paths are *always* absolute thus avoiding common bugs
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let path = Path(userInput) ?? Path.cwd/userInput
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// elegant, chainable syntax
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try Path.home.join("foo").mkdir().join("bar").touch().chmod(0o555)
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// sensible considerations
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try Path.home.join("bar").mkdir()
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try Path.home.join("bar").mkdir() // doesn’t throw ∵ we already have the desired result
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// easy file-management
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let bar = try Path.root.join("foo").copy(to: Path.root/"bar")
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print(bar) // => /bar
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print(bar.isFile) // => true
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// careful API considerations so as to avoid common bugs
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let foo = try Path.root.join("foo").copy(into: Path.root.join("bar").mkdir())
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print(foo) // => /bar/foo
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print(foo.isFile) // => true
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// we support dynamic members (_use_sparingly_):
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let prefs = Path.home.Library.Preferences // => /Users/mxcl/Library/Preferences
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// a practical example: installing a helper executable
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try Bundle.resources.helper.copy(into: Path.root.usr.local.bin).chmod(0o500)
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```
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We emphasize safety and correctness, just like Swift, and also (again like
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Swift), we provide a thoughtful and comprehensive (yet concise) API.
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# Support mxcl
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Hi, I’m Max Howell and I have written a lot of open source software, and
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probably you already use some of it (Homebrew anyone?). I work full-time on
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open source and it’s hard; currently I earn *less* than minimum wage. Please
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help me continue my work, I appreciate it x
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<a href="https://www.patreon.com/mxcl">
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<img src="https://c5.patreon.com/external/logo/become_a_patron_button@2x.png" width="160">
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</a>
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[Other donation/tipping options](http://mxcl.dev/#donate)
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# Handbook
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Our [online API documentation][docs] covers 100% of our public API and is
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automatically updated for new releases.
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## Codable
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We support `Codable` as you would expect:
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```swift
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try JSONEncoder().encode([Path.home, Path.home/"foo"])
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```
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```json
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[
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"/Users/mxcl",
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"/Users/mxcl/foo",
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]
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```
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However, often you want to encode relative paths:
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```swift
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let encoder = JSONEncoder()
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encoder.userInfo[.relativePath] = Path.home
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encoder.encode([Path.home, Path.home/"foo"])
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```
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```json
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[
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"",
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"foo",
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]
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```
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**Note** make sure you decode with this key set *also*, otherwise we `fatal`
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(unless the paths are absolute obv.)
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```swift
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let decoder = JSONDecoder()
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decoder.userInfo[.relativePath] = Path.home
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decoder.decode(from: data)
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```
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## Dynamic members
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We support `@dynamicMemberLookup`:
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```swift
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let ls = Path.root.usr.bin.ls // => /usr/bin/ls
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```
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This is less commonly useful than you would think, hence our documentation
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does not use it. Usually you are joining variables or other `String` arguments
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or trying to describe files (and files usually have extensions). However when
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you need it, it’s *lovely*.
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## Initializing from user-input
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The `Path` initializer returns `nil` unless fed an absolute path; thus to
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initialize from user-input that may contain a relative path use this form:
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```swift
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let path = Path(userInput) ?? Path.cwd/userInput
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```
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This is explicit, not hiding anything that code-review may miss and preventing
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common bugs like accidentally creating `Path` objects from strings you did not
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expect to be relative.
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Our initializer is nameless to be consistent with the equivalent operation for
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converting strings to `Int`, `Float` etc. in the standard library.
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## Extensions
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We have some extensions to Apple APIs:
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```swift
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let bashProfile = try String(contentsOf: Path.home/".bash_profile")
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let history = try Data(contentsOf: Path.home/".history")
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bashProfile += "\n\nfoo"
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try bashProfile.write(to: Path.home/".bash_profile")
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try Bundle.main.resources.join("foo").copy(to: .home)
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```
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## Directory listings
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We provide `ls()`, called because it behaves like the Terminal `ls` function,
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the name thus implies its behavior, ie. that it is not recursive.
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```swift
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for entry in Path.home.ls() {
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print(entry.path)
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print(entry.kind) // .directory or .file
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}
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for entry in Path.home.ls() where entry.kind == .file {
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//…
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}
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for entry in Path.home.ls() where entry.path.mtime > yesterday {
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//…
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}
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let dirs = Path.home.ls().directories
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let files = Path.home.ls().files
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let swiftFiles = Path.home.ls().files(withExtension: "swift")
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```
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# `Path.swift` is robust
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Some parts of `FileManager` are not exactly idiomatic. For example
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`isExecutableFile` returns `true` even if there is no file there, it is instead
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telling you that *if* you made a file there it *could* be executable. Thus we
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check the POSIX permissions of the file first, before returning the result of
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`isExecutableFile`. `Path.swift` has done the leg-work for you so you can get on
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with your work without worries.
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There is also some magic going on in Foundation’s filesystem APIs, which we look
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for and ensure our API is deterministic, eg. [this test].
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[this test]: https://github.com/mxcl/Path.swift/blob/master/Tests/PathTests/PathTests.swift#L539-L554
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# `Path.swift` is properly cross-platform
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`FileManager` on Linux is full of holes. We have found the holes and worked
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round them where necessary.
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# Rules & Caveats
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Paths are just string representations, there *might not* be a real file there.
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```swift
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Path.home/"b" // => /Users/mxcl/b
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// joining multiple strings works as you’d expect
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Path.home/"b"/"c" // => /Users/mxcl/b/c
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// joining multiple parts at a time is fine
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Path.home/"b/c" // => /Users/mxcl/b/c
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// joining with absolute paths omits prefixed slash
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Path.home/"/b" // => /Users/mxcl/b
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// joining with .. or . works as expected
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Path.home.foo.bar.join("..") // => /Users/mxcl/foo
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Path.home.foo.bar.join(".") // => /Users/mxcl/foo/bar
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// of course, feel free to join variables:
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let b = "b"
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let c = "c"
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Path.home/b/c // => /Users/mxcl/b/c
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// tilde is not special here
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Path.root/"~b" // => /~b
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Path.root/"~/b" // => /~/b
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// but is here
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Path("~/foo")! // => /Users/mxcl/foo
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// this works provided the user `Guest` exists
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Path("~Guest") // => /Users/Guest
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// but if the user does not exist
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Path("~foo") // => nil
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// paths with .. or . are resolved
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Path("/foo/bar/../baz") // => /foo/baz
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// symlinks are not resolved
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Path.root.bar.symlink(as: "foo")
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Path("foo") // => /foo
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Path.foo // => /foo
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// unless you do it explicitly
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try Path.foo.readlink() // => /bar
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// `readlink` only resolves the *final* path component,
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// thus use `realpath` if there are multiple symlinks
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```
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*Path.swift* has the general policy that if the desired end result preexists,
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then it’s a noop:
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* If you try to delete a file, but the file doesn't exist, we do nothing.
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* If you try to make a directory and it already exists, we do nothing.
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* If you call `readlink` on a non-symlink, we return `self`
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However notably if you try to copy or move a file with specifying `overwrite`
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and the file already exists at the destination and is identical, we don’t check
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for that as the check was deemed too expensive to be worthwhile.
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## Symbolic links
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* Two paths may represent the same *resolved* path yet not be equal due to
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symlinks in such cases you should use `realpath` on both first if an
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equality check is required.
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* There are several symlink paths on Mac that are typically automatically
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resolved by Foundation, eg. `/private`, we attempt to do the same for
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functions that you would expect it (notably `realpath`), we *do* the same for
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`Path.init`, but *do not* if you are joining a path that ends up being one of
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these paths, (eg. `Path.root.join("var/private')`).
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If a `Path` is a symlink but the destination of the link does not exist `exists`
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returns `false`. This seems to be the correct thing to do since symlinks are
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meant to be an abstraction for filesystems. To instead verify that there is
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no filesystem entry there at all check if `kind` is `nil`.
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## We do not provide change directory functionality
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Changing directory is dangerous, you should *always* try to avoid it and thus
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we don’t even provide the method. If you are executing a sub-process then
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use `Process.currentDirectoryURL`.
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If you must then use `FileManager.changeCurrentDirectory`.
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# I thought I should only use `URL`s?
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Apple recommend this because they provide a magic translation for
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[file-references embodied by URLs][file-refs], which gives you URLs like so:
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file:///.file/id=6571367.15106761
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Therefore, if you are not using this feature you are fine. If you have URLs the correct
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way to get a `Path` is:
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```swift
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if let path = Path(url: url) {
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/*…*/
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}
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```
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Our initializer calls `path` on the URL which resolves any reference to an
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actual filesystem path, however we also check the URL has a `file` scheme first.
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[file-refs]: https://developer.apple.com/documentation/foundation/nsurl/1408631-filereferenceurl
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# Installation
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SwiftPM:
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```swift
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package.append(.package(url: "https://github.com/mxcl/Path.swift.git", from: "0.13.0"))
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```
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CocoaPods:
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```ruby
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pod 'Path.swift', '~> 0.13'
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```
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Carthage:
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> Waiting on: [@Carthage#1945](https://github.com/Carthage/Carthage/pull/1945).
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## Pre‐1.0 status
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We are pre 1.0, thus we can change the API as we like, and we will (to the
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pursuit of getting it *right*)! We will tag 1.0 as soon as possible.
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### Get push notifications for new releases
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https://mxcl.dev/canopy/
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# Alternatives
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* [Pathos](https://github.com/dduan/Pathos) by Daniel Duan
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* [PathKit](https://github.com/kylef/PathKit) by Kyle Fuller
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* [Files](https://github.com/JohnSundell/Files) by John Sundell
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* [Utility](https://github.com/apple/swift-package-manager) by Apple
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[badge-platforms]: https://img.shields.io/badge/platforms-macOS%20%7C%20Linux%20%7C%20iOS%20%7C%20tvOS%20%7C%20watchOS-lightgrey.svg
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[badge-languages]: https://img.shields.io/badge/swift-4.2%20%7C%205.0-orange.svg
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[docs]: https://mxcl.dev/Path.swift/Structs/Path.html
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[badge-jazzy]: https://raw.githubusercontent.com/mxcl/Path.swift/gh-pages/badge.svg?sanitize=true
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[badge-codecov]: https://codecov.io/gh/mxcl/Path.swift/branch/master/graph/badge.svg
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[badge-ci]: https://travis-ci.com/mxcl/Path.swift.svg
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[travis]: https://travis-ci.com/mxcl/Path.swift
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[codecov]: https://codecov.io/gh/mxcl/Path.swift
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[badge-version]: https://img.shields.io/cocoapods/v/Path.swift.svg?label=version
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[cocoapods]: https://cocoapods.org/pods/Path.swift
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