fix: path-related bugs

crates/erg_common/pathutil.rs

@@ -0,0 +1,94 @@
+use std::path::{Component, Path, PathBuf};
+
+pub fn is_cur_dir<P: AsRef<Path>>(path: P) -> bool {
+    path.as_ref()
+        .components()
+        .next()
+        .map_or(false, |c| c == Component::CurDir)
+}
+
+/// ```
+/// # use std::path::{PathBuf};
+/// # use erg_common::pathutil::add_postfix_foreach;
+/// let path = PathBuf::from("erg");
+/// let path = add_postfix_foreach(path, ".d");
+/// assert_eq!(path, PathBuf::from("erg.d"));
+/// let path = PathBuf::from("erg/foo/bar");
+/// let path = add_postfix_foreach(path, ".d");
+/// assert_eq!(path, PathBuf::from("erg.d/foo.d/bar.d"));
+/// ```
+pub fn add_postfix_foreach<P: AsRef<Path>, Q: AsRef<Path>>(path: P, postfix: Q) -> PathBuf {
+    let mut result = PathBuf::new();
+    for c in path.as_ref().components() {
+        match c {
+            Component::Prefix(_) => result.push(c),
+            Component::RootDir => result.push(c),
+            Component::CurDir => result.push(c),
+            Component::ParentDir => result.push(c),
+            Component::Normal(os_str) => {
+                let mut os_string = os_str.to_os_string();
+                os_string.push(postfix.as_ref().as_os_str());
+                result.push(PathBuf::from(os_string));
+            }
+        }
+    }
+    result
+}
+
+pub fn remove_postfix_foreach<P: AsRef<Path>>(path: P, extension: &str) -> PathBuf {
+    let mut result = PathBuf::new();
+    for c in path.as_ref().components() {
+        match c {
+            Component::Prefix(_) => result.push(c),
+            Component::RootDir => result.push(c),
+            Component::CurDir => result.push(c),
+            Component::ParentDir => result.push(c),
+            Component::Normal(os_str) => {
+                let string = os_str.to_string_lossy();
+                result.push(string.trim_end_matches(extension));
+            }
+        }
+    }
+    result
+}
+
+/// cutout the extension from the path, and let file name be the directory name.
+/// ```
+/// # use std::path::{PathBuf};
+/// # use erg_common::pathutil::remove_postfix;
+/// let path = PathBuf::from("erg.d.er");
+/// let path = remove_postfix(path, ".er");
+/// assert_eq!(path, PathBuf::from("erg.d"));
+pub fn remove_postfix<P: AsRef<Path>>(path: P, extension: &str) -> PathBuf {
+    let string = path.as_ref().to_string_lossy();
+    PathBuf::from(string.trim_end_matches(extension))
+}
+
+///
+/// ```
+/// # use std::path::{PathBuf};
+/// # use erg_common::pathutil::squash;
+/// let path = PathBuf::from("erg/../foo");
+/// let path = squash(path);
+/// assert_eq!(path, PathBuf::from("foo"));
+/// let path = PathBuf::from("erg/./foo");
+/// let path = squash(path);
+/// assert_eq!(path, PathBuf::from("erg/foo"));
+/// ```
+pub fn squash(path: PathBuf) -> PathBuf {
+    let mut result = PathBuf::new();
+    for c in path.components() {
+        match c {
+            Component::Prefix(_) => result.push(c),
+            Component::RootDir => result.push(c),
+            Component::CurDir => {}
+            Component::ParentDir => {
+                result.pop();
+            }
+            Component::Normal(os_str) => {
+                result.push(os_str);
+            }
+        }
+    }
+    result
+}