Handle case of missing metadata.json.

src/lib.rs

@@ -383,16 +383,17 @@ impl MovieLibrary {
 
     pub fn update_metadata(&self) -> Result<Vec<String>, Error> {
         let path = Path::new(&self.root).join(FULL_METADATA_FILENAME);
-        // TODO(wathiede): if we fail to parse the old file (i.e. file not found), create an empty
-        // old_metadata and keep going.
 
-        // Open the file in read-only mode with buffer.
-        let f = File::open(&path).context(format!("open {}", path.display()))?;
-        let r = BufReader::new(f);
-
-        // Read the JSON contents of the file as an instance of `User`.
-        let old_metadata: HashMap<String, Value> = serde_json::from_reader(r)
-            .context(format!("serde_json::from_reader {}", path.display()))?;
+        let old_metadata: HashMap<String, Value> = match File::open(&path) {
+            Ok(f) => {
+                let r = BufReader::new(f);
+                serde_json::from_reader(r)?
+            }
+            Err(e) => {
+                error!("Failed to open {}: {}", path.display(), e);
+                HashMap::new()
+            }
+        };
 
         info!("Read metadata, {} videos found", old_metadata.len());