Struct async_std::path::Path

pub struct Path { /* fields omitted */ }

This struct is an async version of std::path::Path.

Methods

impl Path

pub fn new<S: AsRef<OsStr> + ?Sized>(s: &S) -> &Path

Directly wraps a string slice as a Path slice.

This is a cost-free conversion.

Examples

use async_std::path::Path;

Path::new("foo.txt");

You can create Paths from Strings, or even other Paths:

use async_std::path::Path;

let string = String::from("foo.txt");
let from_string = Path::new(&string);
let from_path = Path::new(&from_string);
assert_eq!(from_string, from_path);

pub fn as_os_str(&self) -> &OsStr

Yields the underlying OsStr slice.

pub fn to_str(&self) -> Option<&str>

Yields a &str slice if the Path is valid unicode.

This conversion may entail doing a check for UTF-8 validity. Note that validation is performed because non-UTF-8 strings are perfectly valid for some OS.

Examples

use async_std::path::Path;

let path = Path::new("foo.txt");
assert_eq!(path.to_str(), Some("foo.txt"));

pub fn to_string_lossy(&self) -> Cow<str>

Converts a Path to a Cow<str>.

Any non-Unicode sequences are replaced with U+FFFD REPLACEMENT CHARACTER.

Examples

Calling to_string_lossy on a Path with valid unicode:

use async_std::path::Path;

let path = Path::new("foo.txt");
assert_eq!(path.to_string_lossy(), "foo.txt");

Had path contained invalid unicode, the to_string_lossy call might have returned "fo�.txt".

pub fn to_path_buf(&self) -> PathBuf

Converts a Path to an owned PathBuf.

Examples

use async_std::path::{Path, PathBuf};

let path_buf = Path::new("foo.txt").to_path_buf();
assert_eq!(path_buf, PathBuf::from("foo.txt"));

pub fn is_absolute(&self) -> bool

Returns true if the Path is absolute, i.e., if it is independent of the current directory.

• On Unix, a path is absolute if it starts with the root, so is_absolute and has_root are equivalent.

• On Windows, a path is absolute if it has a prefix and starts with the root: c:\windows is absolute, while c:temp and \temp are not.

Examples

use async_std::path::Path;

assert!(!Path::new("foo.txt").is_absolute());

pub fn is_relative(&self) -> bool

Returns true if the Path is relative, i.e., not absolute.

See is_absolute's documentation for more details.

Examples

use async_std::path::Path;

assert!(Path::new("foo.txt").is_relative());

pub fn has_root(&self) -> bool

Returns true if the Path has a root.

• On Unix, a path has a root if it begins with /.

• On Windows, a path has a root if it:

  • has no prefix and begins with a separator, e.g., \windows
  • has a prefix followed by a separator, e.g., c:\windows but not c:windows
  • has any non-disk prefix, e.g., \\server\share

Examples

use async_std::path::Path;

assert!(Path::new("/etc/passwd").has_root());

pub fn parent(&self) -> Option<&Path>

Returns the Path without its final component, if there is one.

Returns None if the path terminates in a root or prefix.

Examples

use async_std::path::Path;

let path = Path::new("/foo/bar");
let parent = path.parent().unwrap();
assert_eq!(parent, Path::new("/foo"));

let grand_parent = parent.parent().unwrap();
assert_eq!(grand_parent, Path::new("/"));
assert_eq!(grand_parent.parent(), None);

pub fn ancestors(&self) -> Ancestors

Produces an iterator over Path and its ancestors.

The iterator will yield the Path that is returned if the parent method is used zero or more times. That means, the iterator will yield &self, &self.parent().unwrap(), &self.parent().unwrap().parent().unwrap() and so on. If the parent method returns None, the iterator will do likewise. The iterator will always yield at least one value, namely &self.

Examples

use async_std::path::Path;

let mut ancestors = Path::new("/foo/bar").ancestors();
assert_eq!(ancestors.next(), Some(Path::new("/foo/bar").into()));
assert_eq!(ancestors.next(), Some(Path::new("/foo").into()));
assert_eq!(ancestors.next(), Some(Path::new("/").into()));
assert_eq!(ancestors.next(), None);

pub fn file_name(&self) -> Option<&OsStr>

Returns the final component of the Path, if there is one.

If the path is a normal file, this is the file name. If it's the path of a directory, this is the directory name.

Returns None if the path terminates in ...

Examples

use async_std::path::Path;
use std::ffi::OsStr;

assert_eq!(Some(OsStr::new("bin")), Path::new("/usr/bin/").file_name());
assert_eq!(Some(OsStr::new("foo.txt")), Path::new("tmp/foo.txt").file_name());
assert_eq!(Some(OsStr::new("foo.txt")), Path::new("foo.txt/.").file_name());
assert_eq!(Some(OsStr::new("foo.txt")), Path::new("foo.txt/.//").file_name());
assert_eq!(None, Path::new("foo.txt/..").file_name());
assert_eq!(None, Path::new("/").file_name());

pub fn strip_prefix<P>(&self, base: P) -> Result<&Path, StripPrefixError> where
    P: AsRef<Path>, 

Returns a path that, when joined onto base, yields self.

Errors

If base is not a prefix of self (i.e., starts_with returns false), returns Err.

Examples

use async_std::path::{Path, PathBuf};

let path = Path::new("/test/haha/foo.txt");

assert_eq!(path.strip_prefix("/"), Ok(Path::new("test/haha/foo.txt")));
assert_eq!(path.strip_prefix("/test"), Ok(Path::new("haha/foo.txt")));
assert_eq!(path.strip_prefix("/test/"), Ok(Path::new("haha/foo.txt")));
assert_eq!(path.strip_prefix("/test/haha/foo.txt"), Ok(Path::new("")));
assert_eq!(path.strip_prefix("/test/haha/foo.txt/"), Ok(Path::new("")));
assert_eq!(path.strip_prefix("test").is_ok(), false);
assert_eq!(path.strip_prefix("/haha").is_ok(), false);

let prefix = PathBuf::from("/test/");
assert_eq!(path.strip_prefix(prefix), Ok(Path::new("haha/foo.txt")));

pub fn starts_with<P: AsRef<Path>>(&self, base: P) -> bool

Determines whether base is a prefix of self.

Only considers whole path components to match.

Examples

use async_std::path::Path;

let path = Path::new("/etc/passwd");

assert!(path.starts_with("/etc"));
assert!(path.starts_with("/etc/"));
assert!(path.starts_with("/etc/passwd"));
assert!(path.starts_with("/etc/passwd/"));

assert!(!path.starts_with("/e"));

pub fn ends_with<P: AsRef<Path>>(&self, child: P) -> bool

Determines whether child is a suffix of self.

Only considers whole path components to match.

Examples

use async_std::path::Path;

let path = Path::new("/etc/passwd");

assert!(path.ends_with("passwd"));

pub fn file_stem(&self) -> Option<&OsStr>

Extracts the stem (non-extension) portion of self.file_name.

The stem is:

• None, if there is no file name;
• The entire file name if there is no embedded .;
• The entire file name if the file name begins with . and has no other .s within;
• Otherwise, the portion of the file name before the final .

Examples

use async_std::path::Path;

let path = Path::new("foo.rs");

assert_eq!("foo", path.file_stem().unwrap());

pub fn extension(&self) -> Option<&OsStr>

Extracts the extension of self.file_name, if possible.

The extension is:

• None, if there is no file name;
• None, if there is no embedded .;
• None, if the file name begins with . and has no other .s within;
• Otherwise, the portion of the file name after the final .

Examples

use async_std::path::Path;

let path = Path::new("foo.rs");

assert_eq!("rs", path.extension().unwrap());

pub fn join<P: AsRef<Path>>(&self, path: P) -> PathBuf

Creates an owned PathBuf with path adjoined to self.

See PathBuf::push for more details on what it means to adjoin a path.

Examples

use async_std::path::{Path, PathBuf};

assert_eq!(Path::new("/etc").join("passwd"), PathBuf::from("/etc/passwd"));

pub fn with_file_name<S: AsRef<OsStr>>(&self, file_name: S) -> PathBuf

Creates an owned PathBuf like self but with the given file name.

See PathBuf::set_file_name for more details.

Examples

use async_std::path::{Path, PathBuf};

let path = Path::new("/tmp/foo.txt");
assert_eq!(path.with_file_name("bar.txt"), PathBuf::from("/tmp/bar.txt"));

let path = Path::new("/tmp");
assert_eq!(path.with_file_name("var"), PathBuf::from("/var"));

pub fn with_extension<S: AsRef<OsStr>>(&self, extension: S) -> PathBuf

Creates an owned PathBuf like self but with the given extension.

See PathBuf::set_extension for more details.

Examples

use async_std::path::{Path, PathBuf};

let path = Path::new("foo.rs");
assert_eq!(path.with_extension("txt"), PathBuf::from("foo.txt"));

Important traits for Components<'a>

impl<'a> Iterator for Components<'a> type Item = Component<'a>;

pub fn components(&self) -> Components

Produces an iterator over the Components of the path.

When parsing the path, there is a small amount of normalization:

• Repeated separators are ignored, so a/b and a//b both have a and b as components.

• Occurrences of . are normalized away, except if they are at the beginning of the path. For example, a/./b, a/b/, a/b/. and a/b all have a and b as components, but ./a/b starts with an additional CurDir component.

• A trailing slash is normalized away, /a/b and /a/b/ are equivalent.

Note that no other normalization takes place; in particular, a/c and a/b/../c are distinct, to account for the possibility that b is a symbolic link (so its parent isn't a).

Examples

use async_std::path::{Path, Component};
use std::ffi::OsStr;

let mut components = Path::new("/tmp/foo.txt").components();

assert_eq!(components.next(), Some(Component::RootDir));
assert_eq!(components.next(), Some(Component::Normal(OsStr::new("tmp"))));
assert_eq!(components.next(), Some(Component::Normal(OsStr::new("foo.txt"))));
assert_eq!(components.next(), None)

Important traits for Iter<'a>

impl<'a> Iterator for Iter<'a> type Item = &'a OsStr;

pub fn iter(&self) -> Iter

Produces an iterator over the path's components viewed as OsStr slices.

For more information about the particulars of how the path is separated into components, see components.

Examples

use async_std::path::{self, Path};
use std::ffi::OsStr;

let mut it = Path::new("/tmp/foo.txt").iter();
assert_eq!(it.next(), Some(OsStr::new(&path::MAIN_SEPARATOR.to_string())));
assert_eq!(it.next(), Some(OsStr::new("tmp")));
assert_eq!(it.next(), Some(OsStr::new("foo.txt")));
assert_eq!(it.next(), None)

pub fn display(&self) -> Display

Returns an object that implements Display for safely printing paths that may contain non-Unicode data.

Examples

use async_std::path::Path;

let path = Path::new("/tmp/foo.rs");

println!("{}", path.display());

pub async fn metadata<'_>(&'_ self) -> Result<Metadata>

Queries the file system to get information about a file, directory, etc.

This function will traverse symbolic links to query information about the destination file.

This is an alias to fs::metadata.

Examples

use async_std::path::Path;

let path = Path::new("/Minas/tirith");
let metadata = path.metadata().await.expect("metadata call failed");
println!("{:?}", metadata.file_type());

pub async fn symlink_metadata<'_>(&'_ self) -> Result<Metadata>

Queries the metadata about a file without following symlinks.

This is an alias to fs::symlink_metadata.

Examples

use async_std::path::Path;

let path = Path::new("/Minas/tirith");
let metadata = path.symlink_metadata().await.expect("symlink_metadata call failed");
println!("{:?}", metadata.file_type());

pub async fn canonicalize<'_>(&'_ self) -> Result<PathBuf>

Returns the canonical, absolute form of the path with all intermediate components normalized and symbolic links resolved.

This is an alias to fs::canonicalize.

Examples

use async_std::path::{Path, PathBuf};

let path = Path::new("/foo/test/../test/bar.rs");
assert_eq!(path.canonicalize().await.unwrap(), PathBuf::from("/foo/test/bar.rs"));

pub async fn read_link<'_>(&'_ self) -> Result<PathBuf>

Reads a symbolic link, returning the file that the link points to.

This is an alias to fs::read_link.

Examples

use async_std::path::Path;

let path = Path::new("/laputa/sky_castle.rs");
let path_link = path.read_link().await.expect("read_link call failed");

pub async fn read_dir<'_>(&'_ self) -> Result<ReadDir>

Returns an iterator over the entries within a directory.

The iterator will yield instances of io::Result<DirEntry>. New errors may be encountered after an iterator is initially constructed.

This is an alias to fs::read_dir.

Examples

use async_std::fs;
use async_std::path::Path;
use async_std::prelude::*;

let path = Path::new("/laputa");
let mut dir = fs::read_dir(&path).await.expect("read_dir call failed");
while let Some(res) = dir.next().await {
    let entry = res?;
    println!("{}", entry.file_name().to_string_lossy());
}

pub async fn exists<'_>(&'_ self) -> bool

Returns true if the path points at an existing entity.

This function will traverse symbolic links to query information about the destination file. In case of broken symbolic links this will return false.

If you cannot access the directory containing the file, e.g., because of a permission error, this will return false.

Examples

use async_std::path::Path;
assert_eq!(Path::new("does_not_exist.txt").exists().await, false);

See Also

This is a convenience function that coerces errors to false. If you want to check errors, call fs::metadata.

pub async fn is_file<'_>(&'_ self) -> bool

Returns true if the path exists on disk and is pointing at a regular file.

This function will traverse symbolic links to query information about the destination file. In case of broken symbolic links this will return false.

If you cannot access the directory containing the file, e.g., because of a permission error, this will return false.

Examples

use async_std::path::Path;
assert_eq!(Path::new("./is_a_directory/").is_file().await, false);
assert_eq!(Path::new("a_file.txt").is_file().await, true);

See Also

This is a convenience function that coerces errors to false. If you want to check errors, call fs::metadata and handle its Result. Then call fs::Metadata::is_file if it was Ok.

pub async fn is_dir<'_>(&'_ self) -> bool

Returns true if the path exists on disk and is pointing at a directory.

This function will traverse symbolic links to query information about the destination file. In case of broken symbolic links this will return false.

If you cannot access the directory containing the file, e.g., because of a permission error, this will return false.

Examples

use async_std::path::Path;
assert_eq!(Path::new("./is_a_directory/").is_dir().await, true);
assert_eq!(Path::new("a_file.txt").is_dir().await, false);

See Also

This is a convenience function that coerces errors to false. If you want to check errors, call fs::metadata and handle its Result. Then call fs::Metadata::is_dir if it was Ok.

pub fn into_path_buf(self: Box<Path>) -> PathBuf

Converts a Box<Path> into a PathBuf without copying or allocating.

Trait Implementations

impl AsRef<Path> for Path

fn as_ref(&self) -> &Path

Performs the conversion.

impl AsRef<Path> for Path

fn as_ref(&self) -> &Path

Performs the conversion.

impl AsRef<Path> for Path

fn as_ref(&self) -> &Path

Performs the conversion.

impl AsRef<OsStr> for Path

fn as_ref(&self) -> &OsStr

Performs the conversion.

impl AsRef<Path> for OsStr

fn as_ref(&self) -> &Path

Performs the conversion.

impl AsRef<Path> for str

fn as_ref(&self) -> &Path

Performs the conversion.

impl AsRef<Path> for String

fn as_ref(&self) -> &Path

Performs the conversion.

impl AsRef<Path> for PathBuf

fn as_ref(&self) -> &Path

Performs the conversion.

impl AsRef<Path> for PathBuf

fn as_ref(&self) -> &Path

Performs the conversion.

impl<'a> Into<&'a Path> for &'a Path

fn into(self) -> &'a Path

Performs the conversion.

impl<'a> From<&'a Path> for &'a Path

fn from(path: &'a Path) -> &'a Path

Performs the conversion.

impl PartialEq<Path> for Path

fn eq(&self, other: &Path) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Path) -> bool

This method tests for !=.

impl ToOwned for Path

type Owned = PathBuf

The resulting type after obtaining ownership.

fn to_owned(&self) -> PathBuf

Creates owned data from borrowed data, usually by cloning.

fn clone_into(&self, target: &mut Self::Owned)

🔬 This is a nightly-only experimental API. (toowned_clone_into)

recently added

Uses borrowed data to replace owned data, usually by cloning.

impl Debug for Path

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl StructuralPartialEq for Path

impl Borrow<Path> for PathBuf

fn borrow(&self) -> &Path

Immutably borrows from an owned value.