Struct which::CanonicalPath

pub struct CanonicalPath { /* private fields */ }

An owned, immutable wrapper around a PathBuf containing the canonical path of an executable.

The constructed PathBuf is the result of which or which_in followed by Path::canonicalize, but CanonicalPath has the advantage of being a type distinct from std::path::Path and std::path::PathBuf.

It can be beneficial to use CanonicalPath instead of std::path::Path when you want the type system to enforce the need for a path that exists, points to a binary that is executable, is absolute, has all components normalized, and has all symbolic links resolved

Since CanonicalPath implements Deref for std::path::Path, all methods on &std::path::Path are also available to &CanonicalPath values.

Implementations

impl CanonicalPath

pub fn new<T: AsRef<OsStr>>(binary_name: T) -> Result<CanonicalPath>

Returns the canonical path of an executable binary by name.

This calls which and Path::canonicalize and maps the result into a CanonicalPath.

pub fn all<T: AsRef<OsStr>>( binary_name: T, ) -> Result<impl Iterator<Item = Result<CanonicalPath>>>

Returns the canonical paths of an executable binary by name.

This calls which_all and Path::canonicalize and maps the results into CanonicalPaths.

pub fn new_in<T, U, V>( binary_name: T, paths: Option<U>, cwd: V, ) -> Result<CanonicalPath>

where T: AsRef<OsStr>, U: AsRef<OsStr>, V: AsRef<Path>,

Returns the canonical path of an executable binary by name in the path list paths and using the current working directory cwd to resolve relative paths.

This calls which_in and Path::canonicalize and maps the result into a CanonicalPath.

pub fn all_in<T, U, V>( binary_name: T, paths: Option<U>, cwd: V, ) -> Result<impl Iterator<Item = Result<CanonicalPath>>>

where T: AsRef<OsStr>, U: AsRef<OsStr>, V: AsRef<Path>,

Returns all of the canonical paths of an executable binary by name in the path list paths and using the current working directory cwd to resolve relative paths.

This calls which_in_all and Path::canonicalize and maps the result into a CanonicalPath.

pub fn as_path(&self) -> &Path

Returns a reference to a std::path::Path.

pub fn into_path_buf(self) -> PathBuf

Consumes the which::CanonicalPath, yielding its underlying std::path::PathBuf.

Methods from Deref<Target = Path>

pub fn as_os_str(&self) -> &OsStr

Yields the underlying OsStr slice.

Examples

use std::path::Path;

let os_str = Path::new("foo.txt").as_os_str();
assert_eq!(os_str, std::ffi::OsStr::new("foo.txt"));

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 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 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 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 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 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 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.

This means it returns Some("") for relative paths with one component.

Returns None if the path terminates in a root or prefix, or if it’s the empty string.

Examples

use 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);

let relative_path = Path::new("foo/bar");
let parent = relative_path.parent();
assert_eq!(parent, Some(Path::new("foo")));
let grand_parent = parent.and_then(Path::parent);
assert_eq!(grand_parent, Some(Path::new("")));
let great_grand_parent = grand_parent.and_then(Path::parent);
assert_eq!(great_grand_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. If the parent method returns None, the iterator will do likewise. The iterator will always yield at least one value, namely Some(&self). Next it will yield &self.parent(), &self.parent().and_then(Path::parent) and so on.

Examples

use std::path::Path;

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

let mut ancestors = Path::new("../foo/bar").ancestors();
assert_eq!(ancestors.next(), Some(Path::new("../foo/bar")));
assert_eq!(ancestors.next(), Some(Path::new("../foo")));
assert_eq!(ancestors.next(), Some(Path::new("..")));
assert_eq!(ancestors.next(), Some(Path::new("")));
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 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 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!(path.strip_prefix("test").is_err());
assert!(path.strip_prefix("/haha").is_err());

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

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

where P: AsRef<Path>,

Determines whether base is a prefix of self.

Only considers whole path components to match.

Examples

use 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/")); // extra slash is okay
assert!(path.starts_with("/etc/passwd///")); // multiple extra slashes are okay

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

assert!(!Path::new("/etc/foo.rs").starts_with("/etc/foo"));

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

where P: AsRef<Path>,

Determines whether child is a suffix of self.

Only considers whole path components to match.

Examples

use std::path::Path;

let path = Path::new("/etc/resolv.conf");

assert!(path.ends_with("resolv.conf"));
assert!(path.ends_with("etc/resolv.conf"));
assert!(path.ends_with("/etc/resolv.conf"));

assert!(!path.ends_with("/resolv.conf"));
assert!(!path.ends_with("conf")); // use .extension() instead

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 std::path::Path;

assert_eq!("foo", Path::new("foo.rs").file_stem().unwrap());
assert_eq!("foo.tar", Path::new("foo.tar.gz").file_stem().unwrap());

See Also

This method is similar to Path::file_prefix, which extracts the portion of the file name before the first .

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

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

Extracts the prefix of self.file_name.

The prefix is:

• None, if there is no file name;
• The entire file name if there is no embedded .;
• The portion of the file name before the first non-beginning .;
• The entire file name if the file name begins with . and has no other .s within;
• The portion of the file name before the second . if the file name begins with .

Examples

use std::path::Path;

assert_eq!("foo", Path::new("foo.rs").file_prefix().unwrap());
assert_eq!("foo", Path::new("foo.tar.gz").file_prefix().unwrap());

See Also

This method is similar to Path::file_stem, which extracts the portion of the file name before the last .

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

Extracts the extension (without the leading dot) 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 std::path::Path;

assert_eq!("rs", Path::new("foo.rs").extension().unwrap());
assert_eq!("gz", Path::new("foo.tar.gz").extension().unwrap());

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

where P: AsRef<Path>,

Creates an owned PathBuf with path adjoined to self.

If path is absolute, it replaces the current path.

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

Examples

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

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

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

where S: AsRef<OsStr>,

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

See PathBuf::set_file_name for more details.

Examples

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

let path = Path::new("/tmp/foo.png");
assert_eq!(path.with_file_name("bar"), PathBuf::from("/tmp/bar"));
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>(&self, extension: S) -> PathBuf

where S: AsRef<OsStr>,

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

See PathBuf::set_extension for more details.

Examples

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

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

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

pub fn with_added_extension<S>(&self, extension: S) -> PathBuf

where S: AsRef<OsStr>,

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

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

See PathBuf::add_extension for more details.

Examples

#![feature(path_add_extension)]

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

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

let path = Path::new("foo.tar.gz");
assert_eq!(path.with_added_extension(""), PathBuf::from("foo.tar.gz"));
assert_eq!(path.with_added_extension("xz"), PathBuf::from("foo.tar.gz.xz"));
assert_eq!(path.with_added_extension("").with_added_extension("txt"), PathBuf::from("foo.tar.gz.txt"));

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 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)

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 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. This may perform lossy conversion, depending on the platform. If you would like an implementation which escapes the path please use Debug instead.

Examples

use std::path::Path;

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

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

pub fn metadata(&self) -> Result<Metadata, Error>

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 std::path::Path;

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

pub fn symlink_metadata(&self) -> Result<Metadata, Error>

Queries the metadata about a file without following symlinks.

This is an alias to fs::symlink_metadata.

Examples

use std::path::Path;

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

pub fn canonicalize(&self) -> Result<PathBuf, Error>

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 std::path::{Path, PathBuf};

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

pub fn read_link(&self) -> Result<PathBuf, Error>

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

This is an alias to fs::read_link.

Examples

use std::path::Path;

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

pub fn read_dir(&self) -> Result<ReadDir, Error>

Returns an iterator over the entries within a directory.

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

This is an alias to fs::read_dir.

Examples

use std::path::Path;

let path = Path::new("/laputa");
for entry in path.read_dir().expect("read_dir call failed") {
    if let Ok(entry) = entry {
        println!("{:?}", entry.path());
    }
}

pub fn exists(&self) -> bool

Returns true if the path points at an existing entity.

Warning: this method may be error-prone, consider using try_exists() instead! It also has a risk of introducing time-of-check to time-of-use (TOCTOU) bugs.

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

If you cannot access the metadata of the file, e.g. because of a permission error or broken symbolic links, this will return false.

Examples

use std::path::Path;
assert!(!Path::new("does_not_exist.txt").exists());

See Also

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

pub fn try_exists(&self) -> Result<bool, Error>

Returns Ok(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 Ok(false).

Path::exists() only checks whether or not a path was both found and readable. By contrast, try_exists will return Ok(true) or Ok(false), respectively, if the path was verified to exist or not exist. If its existence can neither be confirmed nor denied, it will propagate an Err(_) instead. This can be the case if e.g. listing permission is denied on one of the parent directories.

Note that while this avoids some pitfalls of the exists() method, it still can not prevent time-of-check to time-of-use (TOCTOU) bugs. You should only use it in scenarios where those bugs are not an issue.

This is an alias for std::fs::exists.

Examples

use std::path::Path;
assert!(!Path::new("does_not_exist.txt").try_exists().expect("Can't check existence of file does_not_exist.txt"));
assert!(Path::new("/root/secret_file.txt").try_exists().is_err());

pub 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.

If you cannot access the metadata of the file, e.g. because of a permission error or broken symbolic links, this will return false.

Examples

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

When the goal is simply to read from (or write to) the source, the most reliable way to test the source can be read (or written to) is to open it. Only using is_file can break workflows like diff <( prog_a ) on a Unix-like system for example. See fs::File::open or fs::OpenOptions::open for more information.

pub 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.

If you cannot access the metadata of the file, e.g. because of a permission error or broken symbolic links, this will return false.

Examples

use std::path::Path;
assert_eq!(Path::new("./is_a_directory/").is_dir(), true);
assert_eq!(Path::new("a_file.txt").is_dir(), 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 is_symlink(&self) -> bool

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

This function will not traverse symbolic links. In case of a broken symbolic link this will also return true.

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

Examples

use std::path::Path;
use std::os::unix::fs::symlink;

let link_path = Path::new("link");
symlink("/origin_does_not_exist/", link_path).unwrap();
assert_eq!(link_path.is_symlink(), true);
assert_eq!(link_path.exists(), false);

See Also

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

Trait Implementations

impl AsRef<OsStr> for CanonicalPath

fn as_ref(&self) -> &OsStr

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<Path> for CanonicalPath

fn as_ref(&self) -> &Path

Converts this type into a shared reference of the (usually inferred) input type.

impl Clone for CanonicalPath

fn clone(&self) -> CanonicalPath

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for CanonicalPath

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

Formats the value using the given formatter.

impl Deref for CanonicalPath

type Target = Path

The resulting type after dereferencing.

fn deref(&self) -> &Path

Dereferences the value.

impl PartialEq<CanonicalPath> for PathBuf

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialEq<PathBuf> for CanonicalPath

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialEq for CanonicalPath

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for CanonicalPath

impl StructuralPartialEq for CanonicalPath