refactor (Opus 4.5): modularize and split

crates/lanspread-peer/src/error.rs

@@ -0,0 +1,43 @@
+//! Error types for peer operations.
+
+/// Custom error types for peer operations.
+#[derive(Debug)]
+pub enum PeerError {
+    /// Failed to determine the size of a file.
+    FileSizeDetermination {
+        path: String,
+        source: std::io::Error,
+    },
+    /// Game directory has not been configured.
+    GameDirNotSet,
+    /// General error wrapper.
+    Other(eyre::Report),
+}
+
+impl std::fmt::Display for PeerError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            PeerError::FileSizeDetermination { path, source } => {
+                write!(f, "Failed to determine file size for {path}: {source}")
+            }
+            PeerError::GameDirNotSet => write!(f, "Game directory not set"),
+            PeerError::Other(err) => write!(f, "General error: {err}"),
+        }
+    }
+}
+
+impl std::error::Error for PeerError {
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        match self {
+            PeerError::FileSizeDetermination { source, .. } => Some(source),
+            PeerError::Other(err) => Some(err.root_cause()),
+            PeerError::GameDirNotSet => None,
+        }
+    }
+}
+
+impl From<eyre::Report> for PeerError {
+    fn from(err: eyre::Report) -> Self {
+        PeerError::Other(err)
+    }
+}