diff --git a/src/libstd/path.rs b/src/libstd/path.rs
index 7631a9a44bbe7..bb655c0aa1673 100644
--- a/src/libstd/path.rs
+++ b/src/libstd/path.rs
@@ -2220,6 +2220,92 @@ impl Path {
fs::canonicalize(self)
}
+ /// Returns a cleaned representation of the path with all current
+ /// directory (.) and parent directory (..) references resolved.
+ ///
+ /// This is a purely logical calculation; the file system is not accessed. Namely,
+ /// this leaves symbolic links intact and does not validate that the target exists.
+ ///
+ /// This may change the meaning of a path involving symbolic links and parent directory
+ /// references.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::path::{Path, PathBuf};
+ ///
+ /// let path = Path::new("/recipes/./snacks/../desserts/banana_creme_pie.txt");
+ /// assert_eq!(path.clean(), PathBuf::from("/recipes/desserts/banana_creme_pie.txt"));
+ /// let path = Path::new("../.././lots///of////./separators/");
+ /// assert_eq!(path.clean(), PathBuf::from("../../lots/of/separators"));
+ /// let path = Path::new("/../../../cannot_go_above_root");
+ /// assert_eq!(path.clean(), PathBuf::from("/cannot_go_above_root"));
+ /// ```
+ #[unstable(feature = "path_clean", issue = "47402")]
+ pub fn clean(&self) -> PathBuf {
+ let mut stack: Vec<Component> = vec![];
+
+ // We assume .components() removes redundant consecutive path separators.
+ // Note that .components() also does some normalization of '.' on its own anyways.
+ // This '.' normalization happens to be compatible with the approach below.
+ for component in self.components() {
+ match component {
+ // Drop CurDir components, do not even push onto the stack.
+ Component::CurDir => {},
+
+ // For ParentDir components, we need to use the contents of the stack.
+ Component::ParentDir => {
+ // Look at the top element of stack, if any.
+ let top = stack.last().cloned();
+
+ match top {
+ // A component is on the stack, need more pattern matching.
+ Some(c) => {
+ match c {
+ // Push the ParentDir on the stack.
+ Component::Prefix(_) => { stack.push(component); },
+
+ // The parent of a RootDir is itself, so drop the ParentDir (no-op).
+ Component::RootDir => {},
+
+ // A CurDir should never be found on the stack,
+ // since they are dropped when seen.
+ Component::CurDir => { unreachable!(); },
+
+ // If a ParentDir is found, it must be due to it
+ // piling up at the start of a path.
+ // Push the new ParentDir onto the stack.
+ Component::ParentDir => { stack.push(component); },
+
+ // If a Normal is found, pop it off.
+ Component::Normal(_) => { let _ = stack.pop(); }
+ }
+ },
+
+ // Stack is empty, so path is empty, just push.
+ None => { stack.push(component); }
+ }
+ },
+
+ // All others, simply push onto the stack.
+ _ => { stack.push(component); },
+ }
+ }
+
+ // If an empty PathBuf would be returned, instead return CurDir ('.').
+ if stack.is_empty() {
+ return PathBuf::from(Component::CurDir.as_os_str());
+ }
+
+ let mut norm_path = PathBuf::new();
+
+ for item in &stack {
+ norm_path.push(item.as_os_str());
+ }
+
+ norm_path
+ }
+
/// Reads a symbolic link, returning the file that the link points to.
///
/// This is an alias to [`fs::read_link`].
@@ -4020,6 +4106,165 @@ mod tests {
assert_eq!(format!("a{:#<5}b", Path::new("a").display()), "aa####b");
}
+ #[test]
+ pub fn test_clean() {
+ macro_rules! tc(
+ ($path:expr, $expected:expr) => ( {
+ let mut actual = PathBuf::from($path).clean();
+ assert!(actual.to_str() == Some($expected),
+ "cleaning {:?}: Expected {:?}, got {:?}",
+ $path, $expected,
+ actual.to_str().unwrap());
+ });
+ );
+
+ if cfg!(unix) {
+ tc!("", ".");
+ tc!("/", "/");
+ tc!("//", "/"); /* Double-slash root is a separate entity in POSIX,
+ but in Rust we treat it as a normal root slash. */
+ tc!("foo", "foo");
+ tc!(".", ".");
+ tc!("..", "..");
+ tc!(".foo", ".foo");
+ tc!("..foo", "..foo");
+ tc!("/foo", "/foo");
+ tc!("//foo", "/foo");
+ tc!("./foo/", "foo");
+ tc!("../foo/", "../foo");
+ tc!("/foo/bar", "/foo/bar");
+ tc!("foo/bar", "foo/bar");
+ tc!("foo/.", "foo");
+ tc!("foo//bar", "foo/bar");
+ tc!("./foo//bar//", "foo/bar");
+
+ tc!("foo/bar/baz/..", "foo/bar");
+ tc!("foo/bar/baz/../", "foo/bar");
+ tc!("foo/bar/baz/../..", "foo");
+ tc!("foo/bar/baz/../../..", ".");
+ tc!("foo/bar/baz/../../../..", "..");
+ tc!("foo/bar/baz/../../../../..", "../..");
+ tc!("/foo/bar/baz/../../../../..", "/");
+ tc!("foo/../bar/../baz/../", ".");
+ tc!("/.", "/");
+ tc!("/..", "/");
+ tc!("/../../", "/");
+ } else {
+ // Drive-absolute paths.
+ tc!(r#"X:\ABC\DEF"#, r#"X:\ABC\DEF"#);
+ tc!(r#"X:\"#, r#"X:\"#);
+ tc!(r#"X:\ABC\"#, r#"X:\ABC"#);
+ // tc!(r#"X:\ABC\DEF. ."#, r#"X:\ABC\DEF"#);
+ tc!(r#"X:/ABC/DEF"#, r#"X:\ABC\DEF"#);
+ tc!(r#"X:\ABC\..\XYZ"#, r#"X:\XYZ"#);
+ tc!(r#"X:\ABC\..\..\.."#, r#"X:\"#);
+
+ // Drive-relative paths.
+ tc!(r#"X:DEF\GHI"#, r#"X:DEF\GHI"#);
+ tc!(r#"X:"#, r#"X:"#);
+ // tc!(r#"X:DEF. ."#, r#"X:DEF"#);
+ tc!(r#"Y:"#, r#"Y:"#);
+ tc!(r#"Z:"#, r#"Z:"#);
+ tc!(r#"X:ABC\..\XYZ"#, r#"X:XYZ"#);
+ tc!(r#"X:ABC\..\..\.."#, r#"X:..\.."#);
+
+ // Rooted paths.
+ tc!(r#"\ABC\DEF"#, r#"\ABC\DEF"#);
+ tc!(r#"\"#, r#"\"#);
+ // tc!(r#"\ABC\DEF. ."#, r#"\ABC\DEF"#);
+ tc!(r#"/ABC/DEF"#, r#"\ABC\DEF"#);
+ tc!(r#"\ABC\..\XYZ"#, r#"\XYZ"#);
+ tc!(r#"\ABC\..\..\.."#, r#"\"#);
+
+ // Relative paths.
+ tc!(r#"ABC\DEF"#, r#"ABC\DEF"#);
+ tc!(r#"."#, r#"."#);
+ // tc!(r#"ABC\DEF. ."#, r#"ABC\DEF"#);
+ tc!(r#"ABC/DEF"#, r#"ABC\DEF"#);
+ tc!(r#"..\ABC"#, r#"..\ABC"#);
+ tc!(r#"ABC\..\..\.."#, r#"..\.."#);
+
+ // UNC absolute paths.
+ tc!(r#"\\server\share\ABC\DEF"#, r#"\\server\share\ABC\DEF"#);
+ tc!(r#"\\server"#, r#"\\server\"#);
+ tc!(r#"\\server\share"#, r#"\\server\share\"#);
+ // tc!(r#"\\server\share\ABC. ."#, r#"\\server\share\ABC"#);
+ // tc!(r#"//server/share/ABC/DEF"#, r#"\\server\share\ABC\DEF"#);
+ tc!(r#"\\server\share\ABC\..\XYZ"#, r#"\\server\share\XYZ"#);
+ tc!(r#"\\server\share\ABC\..\..\.."#, r#"\\server\share\"#);
+
+ // Local device paths.
+ tc!(r#"\\.\COM20"#, r#"\\.\COM20\"#);
+ tc!(r#"\\.\pipe\mypipe"#, r#"\\.\pipe\mypipe"#);
+ // tc!(r#"\\.\X:\ABC\DEF. ."#, r#"\\.\X:\ABC\DEF"#);
+ // tc!(r#"\\.\X:/ABC/DEF"#, r#"\\.\X:\ABC\DEF"#);
+ tc!(r#"\\.\X:\ABC\..\XYZ"#, r#"\\.\X:\XYZ"#);
+ // tc!(r#"\\.\X:\ABC\..\..\C:\"#, r#"\\.\C:\"#);
+ tc!(r#"\\.\pipe\mypipe\..\notmine"#, r#"\\.\pipe\notmine"#);
+
+ // More local device paths.
+ // tc!(r#"COM1"#, r#"\\.\COM1"#);
+ // tc!(r#"X:\COM1"#, r#"\\.\COM1"#);
+ // tc!(r#"X:COM1"#, r#"\\.\COM1"#);
+ // tc!(r#"valid\COM1"#, r#"\\.\COM1"#);
+ // tc!(r#"X:\notvalid\COM1"#, r#"\\.\COM1"#);
+ // tc!(r#"X:\COM1.blah"#, r#"\\.\COM1"#);
+ // tc!(r#"X:\COM1:blah"#, r#"\\.\COM1"#);
+ // tc!(r#"X:\COM1 .blah"#, r#"\\.\COM1"#);
+ // tc!(r#"\\.\X:\COM1"#, r#"\\.\X:\COM1"#);
+ // tc!(r#"\\abc\xyz\COM1"#, r#"\\abc\xyz\COM1"#);
+
+ // Root local device paths.
+ tc!(r#"\\?\X:\ABC\DEF"#, r#"\\?\X:\ABC\DEF"#);
+ tc!(r#"\\?\X:\"#, r#"\\?\X:\"#);
+ tc!(r#"\\?\X:"#, r#"\\?\X:"#);
+ tc!(r#"\\?\X:\COM1"#, r#"\\?\X:\COM1"#);
+ // tc!(r#"\\?\X:\ABC\DEF. ."#, r#"\\?\X:\ABC\DEF"#);
+ // tc!(r#"\\?\X:/ABC/DEF"#, r#"\\?\X:\ABC\DEF"#);
+ tc!(r#"\\?\X:\ABC\..\XYZ"#, r#"\\?\X:\XYZ"#);
+ tc!(r#"\\?\X:\ABC\..\..\.."#, r#"\\?\X:\"#);
+
+ // More root local device paths.
+ // tc!(r#"\??\X:\ABC\DEF"#, r#"X:\??\X:\ABC\DEF"#);
+ // tc!(r#"\??\X:\"#, r#"X:\??\X:\"#);
+ // tc!(r#"\??\X:"#, r#"X:\??\X:"#);
+ // tc!(r#"\??\X:\COM1"#, r#"X:\??\X:\COM1"#);
+ // tc!(r#"\??\X:\ABC\DEF. ."#, r#"X:\??\X:\ABC\DEF"#);
+ // tc!(r#"\??\X:/ABC/DEF"#, r#"X:\??\X:\ABC\DEF"#);
+ // tc!(r#"\??\X:\ABC\..\XYZ"#, r#"X:\??\X:\XYZ"#);
+ // tc!(r#"\??\X:\ABC\..\..\.."#, r#"X:\"#);
+
+ tc!(r#"a\b\c"#, r#"a\b\c"#);
+ tc!(r#"a/b\c"#, r#"a\b\c"#);
+ tc!(r#"a/b\c\"#, r#"a\b\c"#);
+ tc!(r#"a/b\c/"#, r#"a\b\c"#);
+ tc!(r#"\"#, r#"\"#);
+ tc!(r#"\\"#, r#"\"#);
+ tc!(r#"/"#, r#"\"#);
+ tc!(r#"//"#, r#"\"#);
+
+ tc!(r#"C:\a\b"#, r#"C:\a\b"#);
+ tc!(r#"C:\"#, r#"C:\"#);
+ tc!(r#"C:\."#, r#"C:\"#);
+ tc!(r#"C:\.."#, r#"C:\"#);
+ tc!(r#"C:a"#, r#"C:a"#);
+ tc!(r#"C:."#, r#"C:."#);
+ tc!(r#"C:.."#, r#"C:.."#);
+
+ // Should these not have a trailing slash?
+ tc!(r#"\\server\share"#, r#"\\server\share\"#);
+ tc!(r#"\\server\share\a\b"#, r#"\\server\share\a\b"#);
+ tc!(r#"\\server\share\a\.\b"#, r#"\\server\share\a\b"#);
+ tc!(r#"\\server\share\a\..\b"#, r#"\\server\share\b"#);
+ tc!(r#"\\server\share\a\b\"#, r#"\\server\share\a\b"#);
+
+ tc!(r#"\\?\a\b"#, r#"\\?\a\b"#);
+ tc!(r#"\\?\a/\\b\"#, r#"\\?\a/\\b"#);
+ tc!(r#"\\?\a/\\b/"#, r#"\\?\a/\\b/"#);
+ tc!(r#"\\?\a\b"#, r#"\\?\a\b"#);
+ }
+ }
+
#[test]
fn into_rc() {
let orig = "hello/world";