下载/主界面优化

src-tauri/src/download_engine/storage.rs

@@ -38,6 +38,10 @@ pub struct Storage {
 
 impl Storage {
     pub fn new(data_dir: PathBuf) -> Self {
+        // 确保数据目录存在（首次启动或目录被删除时自动创建）
+        if let Err(e) = fs::create_dir_all(&data_dir) {
+            eprintln!("[download_engine] 创建数据目录失败: {} ({})", data_dir.display(), e);
+        }
         let state_path = data_dir.join("engine_state.json");
         let existing = Self::load_raw(&state_path);
         let next_id = existing.as_ref().map(|s| s.next_id).unwrap_or(1);
@@ -70,6 +74,10 @@ impl Storage {
         state.next_id = self.id_counter.load(Ordering::SeqCst);
         match serde_json::to_string_pretty(&state) {
             Ok(json) => {
+                // 兜底：若父目录被外部删除则在写入前重建
+                if let Some(parent) = self.state_path.parent() {
+                    let _ = fs::create_dir_all(parent);
+                }
                 if let Err(e) = fs::write(&self.state_path, json) {
                     eprintln!("[download_engine] 保存状态失败: {}", e);
                 }