性能优化

src-tauri/src/download_engine/storage.rs

@@ -40,7 +40,7 @@ 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);
+            crate::logger::log_error("download", &format!("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);
@@ -68,23 +68,24 @@ impl Storage {
         Self::load_raw(&self.state_path).unwrap_or_default()
     }
 
-    /// 保存状态到磁盘
-    pub fn save(&self, mut state: EngineState) {
+    /// 保存状态到磁盘（原子写：先写 .tmp 再 rename 覆盖，
+    /// 避免进程崩溃时产生半写/截断的状态文件导致任务列表丢失）
+    /// 失败返回 Err，由调用方决定是否将任务置为 Error（防止"看似已保存"的假象）。
+    pub fn save(&self, mut state: EngineState) -> Result<(), String> {
         // 同步 ID 计数器
         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);
-                }
-            }
-            Err(e) => {
-                eprintln!("[download_engine] 序列化状态失败: {}", e);
-            }
+        let json = serde_json::to_string_pretty(&state)
+            .map_err(|e| format!("序列化状态失败: {}", e))?;
+        // 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);
         }
+        let tmp_path = PathBuf::from(format!("{}.tmp", self.state_path.display()));
+        fs::write(&tmp_path, json).map_err(|e| format!("保存状态失败: {}", e))?;
+        fs::rename(&tmp_path, &self.state_path).map_err(|e| {
+            let _ = fs::remove_file(&tmp_path);
+            format!("替换状态文件失败: {}", e)
+        })?;
+        Ok(())
     }
 }