Try and fix bug

Signed-off-by: Adam Gutglick <adam@spiraldb.com>

Author: AdamGS

url/src/lib.rs

@@ -3122,6 +3122,37 @@ fn file_url_segments_to_pathbuf(
     file_url_segments_to_pathbuf_windows(estimated_capacity, host, segments)
 }
 
+// Build this unconditionally to alleviate https://github.com/servo/rust-url/issues/102
+#[cfg(feature = "std")]
+#[cfg_attr(not(windows), allow(dead_code))]
+fn decode_windows_drive_path_segment(segment: &str) -> Result<String, ()> {
+    use percent_encoding::percent_decode_str;
+
+    // `path_segments_mut()` encodes separators inside a segment, but Windows
+    // file paths still need to round-trip through `to_file_path()`.
+    let decoded = percent_decode_str(segment).decode_utf8().map_err(|_| ())?;
+    let bytes = decoded.as_bytes();
+    if bytes.len() < 2 || !parser::ascii_alpha(bytes[0] as char) || bytes[1] != b':' {
+        return Err(());
+    }
+
+    if bytes.len() == 2 {
+        return Ok(decoded.into_owned());
+    }
+
+    if !matches!(bytes[2], b'\\' | b'/') {
+        return Err(());
+    }
+
+    let mut normalized = String::with_capacity(decoded.len());
+    normalized.push(bytes[0] as char);
+    normalized.push(':');
+    for c in decoded[2..].chars() {
+        normalized.push(if c == '/' { '\\' } else { c });
+    }
+    Ok(normalized)
+}
+
 // Build this unconditionally to alleviate https://github.com/servo/rust-url/issues/102
 #[cfg(feature = "std")]
 #[cfg_attr(not(windows), allow(dead_code))]
@@ -3138,31 +3169,7 @@ fn file_url_segments_to_pathbuf_windows(
         string.push_str(host);
     } else {
         let first = segments.next().ok_or(())?;
-
-        match first.len() {
-            2 => {
-                if !first.starts_with(parser::ascii_alpha) || first.as_bytes()[1] != b':' {
-                    return Err(());
-                }
-
-                string.push_str(first);
-            }
-
-            4 => {
-                if !first.starts_with(parser::ascii_alpha) {
-                    return Err(());
-                }
-                let bytes = first.as_bytes();
-                if bytes[1] != b'%' || bytes[2] != b'3' || (bytes[3] != b'a' && bytes[3] != b'A') {
-                    return Err(());
-                }
-
-                string.push_str(&first[0..1]);
-                string.push(':');
-            }
-
-            _ => return Err(()),
-        }
+        string.push_str(&decode_windows_drive_path_segment(first)?);
     };
 
     for segment in segments {
@@ -3191,6 +3198,37 @@ fn file_url_segments_to_pathbuf_windows(
     Ok(path)
 }
 
+#[cfg(all(test, feature = "std"))]
+mod tests {
+    use super::decode_windows_drive_path_segment;
+    use alloc::string::String;
+
+    #[test]
+    fn decode_windows_drive_path_segment_accepts_drive_letter_only() {
+        assert_eq!(
+            decode_windows_drive_path_segment("C%3A"),
+            Ok(String::from("C:"))
+        );
+    }
+
+    #[test]
+    fn decode_windows_drive_path_segment_accepts_encoded_separators() {
+        assert_eq!(
+            decode_windows_drive_path_segment("C:%5CUsers%5Cme"),
+            Ok(String::from(r"C:\Users\me"))
+        );
+        assert_eq!(
+            decode_windows_drive_path_segment("C:%2FUsers%2Fme"),
+            Ok(String::from(r"C:\Users\me"))
+        );
+    }
+
+    #[test]
+    fn decode_windows_drive_path_segment_rejects_drive_relative_paths() {
+        assert_eq!(decode_windows_drive_path_segment("C:Users"), Err(()));
+    }
+}
+
 /// Implementation detail of `Url::query_pairs_mut`. Typically not used directly.
 #[derive(Debug)]
 pub struct UrlQuery<'a> {

url/tests/unit.rs

@@ -219,6 +219,29 @@ fn new_path_windows_fun() {
     assert_eq!(url.to_file_path(), Ok(PathBuf::from(r"C:\foo\bar")));
 }
 
+#[test]
+#[cfg(all(feature = "std", windows))]
+fn windows_to_file_path_accepts_encoded_separators_in_first_segment() {
+    let url = Url::parse("file:///C:%5Cfoo%5Cbar").unwrap();
+    assert_eq!(url.to_file_path(), Ok(PathBuf::from(r"C:\foo\bar")));
+
+    let url = Url::parse("file:///C:%2Ffoo%2Fbar").unwrap();
+    assert_eq!(url.to_file_path(), Ok(PathBuf::from(r"C:\foo\bar")));
+}
+
+#[test]
+#[cfg(all(feature = "std", windows))]
+fn windows_to_file_path_accepts_drive_path_from_path_segments_mut() {
+    let mut url = Url::parse("file://").unwrap();
+    url.path_segments_mut()
+        .unwrap()
+        .pop_if_empty()
+        .push(r"C:\foo\bar");
+
+    assert_eq!(url.as_str(), "file:///C:%5Cfoo%5Cbar");
+    assert_eq!(url.to_file_path(), Ok(PathBuf::from(r"C:\foo\bar")));
+}
+
 #[test]
 #[cfg(all(
     feature = "std",