uucore::fs: add fn resolve_relative_path

src/uucore/fs.rs

@@ -1,18 +1,39 @@
-/*
- * This file is part of the uutils coreutils package.
- *
- * (c) Joseph Crail <jbcrail@gmail.com>
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
+// This file is part of the uutils coreutils package.
+//
+// (c) Joseph Crail <jbcrail@gmail.com>
+// (c) Jian Zeng <anonymousknight96 AT gmail.com>
+//
+// For the full copyright and license information, please view the LICENSE
+// file that was distributed with this source code.
+//
 
 #[cfg(unix)]
 use super::libc;
 use std::env;
 use std::fs;
-use std::io::{Error, ErrorKind, Result};
+use std::io::{Error, ErrorKind};
+use std::io::Result as IOResult;
 use std::path::{Component, Path, PathBuf};
+use std::borrow::Cow;
+
+#[cfg(unix)]
+pub fn resolve_relative_path<'a>(path: &'a Path) -> Cow<'a, Path> {
+    if path.is_absolute() {
+        return path.into();
+    }
+    let mut result = env::current_dir().unwrap_or(PathBuf::from("/"));
+    for comp in path.components() {
+        match comp {
+            Component::ParentDir => {
+                result.pop();
+            }
+            Component::CurDir => (),
+            Component::Normal(s) => result.push(s),
+            _ => unreachable!(),
+        }
+    }
+    result.into()
+}
 
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 pub enum CanonicalizeMode {
@@ -22,7 +43,7 @@ pub enum CanonicalizeMode {
     Missing,
 }
 
-fn resolve<P: AsRef<Path>>(original: P) -> Result<PathBuf> {
+fn resolve<P: AsRef<Path>>(original: P) -> IOResult<PathBuf> {
     const MAX_LINKS_FOLLOWED: u32 = 255;
     let mut followed = 0;
     let mut result = original.as_ref().to_path_buf();
@@ -40,7 +61,7 @@ fn resolve<P: AsRef<Path>>(original: P) -> Result<PathBuf> {
                     Ok(path) => {
                         result.pop();
                         result.push(path);
-                    },
+                    }
                     Err(e) => {
                         return Err(e);
                     }
@@ -51,7 +72,7 @@ fn resolve<P: AsRef<Path>>(original: P) -> Result<PathBuf> {
     Ok(result)
 }
 
-pub fn canonicalize<P: AsRef<Path>>(original: P, can_mode: CanonicalizeMode) -> Result<PathBuf> {
+pub fn canonicalize<P: AsRef<Path>>(original: P, can_mode: CanonicalizeMode) -> IOResult<PathBuf> {
     // Create an absolute path
     let original = original.as_ref();
     let original = if original.is_absolute() {
@@ -61,20 +82,21 @@ pub fn canonicalize<P: AsRef<Path>>(original: P, can_mode: CanonicalizeMode) ->
     };
 
     let mut result = PathBuf::new();
-    let mut parts = vec!();
+    let mut parts = vec![];
 
     // Split path by directory separator; add prefix (Windows-only) and root
     // directory to final path buffer; add remaining parts to temporary
     // vector for canonicalization.
     for part in original.components() {
         match part {
-            Component::Prefix(_) | Component::RootDir => {
+            Component::Prefix(_) |
+            Component::RootDir => {
                 result.push(part.as_os_str());
-            },
-            Component::CurDir => {},
+            }
+            Component::CurDir => (),
             Component::ParentDir => {
                 parts.pop();
-            },
+            }
             Component::Normal(_) => {
                 parts.push(part.as_os_str());
             }
@@ -83,7 +105,7 @@ pub fn canonicalize<P: AsRef<Path>>(original: P, can_mode: CanonicalizeMode) ->
 
     // Resolve the symlinks where possible
     if !parts.is_empty() {
-        for part in parts[..parts.len()-1].iter() {
+        for part in parts[..parts.len() - 1].iter() {
             result.push(part);
 
             if can_mode == CanonicalizeMode::None {
@@ -91,10 +113,12 @@ pub fn canonicalize<P: AsRef<Path>>(original: P, can_mode: CanonicalizeMode) ->
             }
 
             match resolve(&result) {
-                Err(e) => match can_mode {
-                    CanonicalizeMode::Missing => continue,
-                    _ => return Err(e)
-                },
+                Err(e) => {
+                    match can_mode {
+                        CanonicalizeMode::Missing => continue,
+                        _ => return Err(e),
+                    }
+                }
                 Ok(path) => {
                     result.pop();
                     result.push(path);
@@ -105,7 +129,11 @@ pub fn canonicalize<P: AsRef<Path>>(original: P, can_mode: CanonicalizeMode) ->
         result.push(parts.last().unwrap());
 
         match resolve(&result) {
-            Err(e) => { if can_mode == CanonicalizeMode::Existing { return Err(e); } },
+            Err(e) => {
+                if can_mode == CanonicalizeMode::Existing {
+                    return Err(e);
+                }
+            }
             Ok(path) => {
                 result.pop();
                 result.push(path);