下载/主界面优化

src-tauri/src/download_engine/engine.rs

@@ -158,9 +158,10 @@ impl DownloadEngine {
 
         let id = self.inner.storage.next_task_id();
 
-        // 创建分段
+        // 创建分段（受 continue_download 设置控制：关闭时强制单线程、不支持续传）
+        let resume_enabled = settings.continue_download;
         let segments = match &probe {
-            Ok(p) if p.supports_resume && p.total_size.map(|s| s > 0).unwrap_or(false) => {
+            Ok(p) if resume_enabled && p.supports_resume && p.total_size.map(|s| s > 0).unwrap_or(false) => {
                 split_segments(p.total_size.unwrap(), settings.max_connections)
             }
             _ => vec![Segment {
@@ -172,7 +173,8 @@ impl DownloadEngine {
         };
 
         let total_size = probe.as_ref().ok().and_then(|p| p.total_size).unwrap_or(0);
-        let supports_resume = probe.as_ref().ok().map(|p| p.supports_resume).unwrap_or(false);
+        let supports_resume = resume_enabled
+            && probe.as_ref().ok().map(|p| p.supports_resume).unwrap_or(false);
 
         let task = DownloadTask {
             id: id.clone(),

src-tauri/src/download_engine/http_dl.rs

@@ -318,13 +318,14 @@ async fn download_segment_with_client(
         match stream.next().await {
             Some(Ok(chunk)) => {
                 buf.extend_from_slice(&chunk);
+                // 接收到数据立即更新进度（避免监控周期内进度无变化导致速度显示为 0）
+                local_completed += chunk.len() as u64;
+                progress.store(local_completed, Ordering::Relaxed);
                 // 积累到 64KB 再写入（减少 I/O 次数）
                 if buf.len() >= 64 * 1024 {
                     file.write_all(&buf)
                         .await
                         .map_err(|e| format!("写入文件失败: {}", e))?;
-                    local_completed += buf.len() as u64;
-                    progress.store(local_completed, Ordering::Relaxed);
                     // 限速
                     limiter.consume(buf.len() as u64).await;
                     buf.clear();
@@ -339,8 +340,7 @@ async fn download_segment_with_client(
                     file.write_all(&buf)
                         .await
                         .map_err(|e| format!("写入文件失败: {}", e))?;
-                    local_completed += buf.len() as u64;
-                    progress.store(local_completed, Ordering::Relaxed);
+                    // local_completed 和 progress 已在接收 chunk 时更新
                     limiter.consume(buf.len() as u64).await;
                     buf.clear();
                 }

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);
                 }