Create shared file utiity module

1 files changed, 84 insertions, 0 deletions

diff --git a/src/file_utils.rs b/src/file_utils.rs
new file mode 100644
index 0000000..fdd68ba
--- /dev/null
+++ b/src/file_utils.rs
@@ -0,0 +1,84 @@
+use std::path::{Component, Path, PathBuf};
+
+/// Guarantee that the path is relative and cannot traverse back to parent directories
+/// and optionally prevent traversing hidden directories.
+///
+/// See the unit tests tests::test_sanitize_path* for examples
+pub fn sanitize_path(path: &Path, traverse_hidden: bool) -> Option<PathBuf> {
+    let mut buf = PathBuf::new();
+
+    for comp in path.components() {
+        match comp {
+            Component::Normal(name) => buf.push(name),
+            Component::ParentDir => {
+                buf.pop();
+            }
+            _ => (),
+        }
+    }
+
+    // Double-check that all components are Normal and check for hidden dirs
+    for comp in buf.components() {
+        match comp {
+            Component::Normal(_) if traverse_hidden => (),
+            Component::Normal(name) if !name.to_str()?.starts_with('.') => (),
+            _ => return None,
+        }
+    }
+
+    Some(buf)
+}
+
+/// Returns if a path goes through a symbolic link
+pub fn contains_symlink(path: &PathBuf) -> bool {
+    let mut joined_path = PathBuf::new();
+    for path_slice in path {
+        joined_path = joined_path.join(path_slice);
+        if !joined_path.exists() {
+            // On Windows, `\\?\` won't exist even though it's the root
+            // So, we can't just return here
+            // But we don't need to check if it's a symlink since it won't be
+            continue;
+        }
+        if joined_path
+            .symlink_metadata()
+            .map(|m| m.file_type().is_symlink())
+            .unwrap_or(false)
+        {
+            return true;
+        }
+    }
+    false
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use pretty_assertions::assert_eq;
+    use rstest::rstest;
+
+    #[rstest]
+    #[case("/foo", "foo")]
+    #[case("////foo", "foo")]
+    #[case("C:/foo", if cfg!(windows) { "foo" } else { "C:/foo" })]
+    #[case("../foo", "foo")]
+    #[case("../foo/../bar/abc", "bar/abc")]
+    fn test_sanitize_path(#[case] input: &str, #[case] output: &str) {
+        assert_eq!(
+            sanitize_path(Path::new(input), true).unwrap(),
+            Path::new(output)
+        );
+        assert_eq!(
+            sanitize_path(Path::new(input), false).unwrap(),
+            Path::new(output)
+        );
+    }
+
+    #[rstest]
+    #[case(".foo")]
+    #[case("/.foo")]
+    #[case("foo/.bar/foo")]
+    fn test_sanitize_path_no_hidden_files(#[case] input: &str) {
+        assert_eq!(sanitize_path(Path::new(input), false), None);
+    }
+}