Implement Error for PathError

src/lib.rs

@@ -17,7 +17,11 @@ pub struct Path {
 }
 
 #[derive(Debug)]
-pub struct PathError;
+pub enum PathError {
+    Format,
+    Length,
+    Range,
+}
 
 impl Inner {
     fn next(&mut self) -> Vec<u16> {
@@ -66,7 +70,7 @@ impl Path {
         let inner = bytes
             .chunks(2)
             .map(|chunk| {
-                let be_bytes: [u8; 2] = chunk.try_into().map_err(|_| PathError)?;
+                let be_bytes: [u8; 2] = chunk.try_into().map_err(|_| PathError::Length)?;
                 Ok(u16::from_be_bytes(be_bytes))
             })
             .collect::<Result<_, PathError>>()?;
@@ -91,12 +95,12 @@ impl Path {
         }
 
         if inner.len().saturating_sub(1) != inner[0].into() {
-            return Err(PathError);
+            return Err(PathError::Format);
         }
 
         for elem in inner.iter() {
             if *elem > 999 {
-                return Err(PathError);
+                return Err(PathError::Range);
             }
         }
 
@@ -118,3 +122,21 @@ impl Path {
             .collect()
     }
 }
+
+impl std::fmt::Display for PathError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            PathError::Format => {
+                write!(f, "Invalid path format")
+            }
+            PathError::Length => {
+                write!(f, "Invalid segment length")
+            }
+            PathError::Range => {
+                write!(f, "Invalid segment format")
+            }
+        }
+    }
+}
+
+impl std::error::Error for PathError {}