1 files changed, 80 insertions, 0 deletions
diff --git a/runtime/fs_util.rs b/runtime/fs_util.rs
new file mode 100644
index 000000000..028538d4f
--- /dev/null
+++ b/runtime/fs_util.rs
@@ -0,0 +1,80 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+use deno_core::error::AnyError;
+pub use deno_core::normalize_path;
+use std::env::current_dir;
+use std::io::Error;
+use std::path::{Path, PathBuf};
+
+/// Similar to `std::fs::canonicalize()` but strips UNC prefixes on Windows.
+pub fn canonicalize_path(path: &Path) -> Result<PathBuf, Error> {
+  let mut canonicalized_path = path.canonicalize()?;
+  if cfg!(windows) {
+    canonicalized_path = PathBuf::from(
+      canonicalized_path
+        .display()
+        .to_string()
+        .trim_start_matches("\\\\?\\"),
+    );
+  }
+  Ok(canonicalized_path)
+}
+
+pub fn resolve_from_cwd(path: &Path) -> Result<PathBuf, AnyError> {
+  let resolved_path = if path.is_absolute() {
+    path.to_owned()
+  } else {
+    let cwd = current_dir().unwrap();
+    cwd.join(path)
+  };
+
+  Ok(normalize_path(&resolved_path))
+}
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+
+  #[test]
+  fn resolve_from_cwd_child() {
+    let cwd = current_dir().unwrap();
+    assert_eq!(resolve_from_cwd(Path::new("a")).unwrap(), cwd.join("a"));
+  }
+
+  #[test]
+  fn resolve_from_cwd_dot() {
+    let cwd = current_dir().unwrap();
+    assert_eq!(resolve_from_cwd(Path::new(".")).unwrap(), cwd);
+  }
+
+  #[test]
+  fn resolve_from_cwd_parent() {
+    let cwd = current_dir().unwrap();
+    assert_eq!(resolve_from_cwd(Path::new("a/..")).unwrap(), cwd);
+  }
+
+  #[test]
+  fn test_normalize_path() {
+    assert_eq!(normalize_path(Path::new("a/../b")), PathBuf::from("b"));
+    assert_eq!(normalize_path(Path::new("a/./b/")), PathBuf::from("a/b/"));
+    assert_eq!(
+      normalize_path(Path::new("a/./b/../c")),
+      PathBuf::from("a/c")
+    );
+
+    if cfg!(windows) {
+      assert_eq!(
+        normalize_path(Path::new("C:\\a\\.\\b\\..\\c")),
+        PathBuf::from("C:\\a\\c")
+      );
+    }
+  }
+
+  // TODO: Get a good expected value here for Windows.
+  #[cfg(not(windows))]
+  #[test]
+  fn resolve_from_cwd_absolute() {
+    let expected = Path::new("/a");
+    assert_eq!(resolve_from_cwd(expected).unwrap(), expected);
+  }
+}