Implement keywords_file option

Signed-off-by: hr567 <hr567@hr567.me>

src/main.rs

@@ -30,7 +30,14 @@ struct Args {
     keywords: Vec<String>,
 }
 
-static ARGS: Lazy<Args> = Lazy::new(Args::parse);
+static ARGS: Lazy<Args> = Lazy::new(|| {
+    let mut args = Args::parse();
+    if let Some(keywords_file) = args.keywords_file.take() {
+        let content = std::fs::read_to_string(keywords_file).expect("failed to read keywords file");
+        args.keywords.extend(content.lines().map(|s| s.to_string()));
+    }
+    args
+});
 thread_local! {
     static ANALYZER: OnceCell<AhoCorasick> = const { OnceCell::new() };
 }