Add cancelable scans and improve UI feedback

Enable cancellation for folder/file scans and improve front-end feedback. In Rust, reset the cancel flag at scan start and check it while enumerating folders and before spawning file tasks so long-running scans can be stopped. In React, swallow "Cancelled" errors (no alert), filter incoming hash-progress events to the active file, add filePath as a listener dependency, and track isScanning state. Disable the Scan button during scans, show a Cancel button that invokes cancel_hashing, clear previous results at scan start, and display a LinearProgress bar while scanning.

Author: oop7

src-tauri/src/main.rs

@@ -312,11 +312,16 @@ struct FileData {
 
 #[command]
 async fn scan_folder(window: Window, state: tauri::State<'_, AppState>, folder_path: String, include_subfolders: bool, include_hidden: bool, algorithms: Vec<String>) -> Result<Vec<FileData>, String> {
+    state.cancel.store(false, Ordering::SeqCst);
+    
     // First, collect files to process
     let mut files_to_process: Vec<String> = Vec::new();
     let mut folders_to_scan = vec![folder_path];
 
     while let Some(folder) = folders_to_scan.pop() {
+        if state.cancel.load(Ordering::SeqCst) {
+            break;
+        }
         let mut entries = tokio::fs::read_dir(folder).await.map_err(|e| e.to_string())?;
 
         while let Some(entry) = entries.next_entry().await.map_err(|e| e.to_string())? {
@@ -338,6 +343,9 @@ async fn scan_folder(window: Window, state: tauri::State<'_, AppState>, folder_p
     let mut handles = Vec::new();
 
     for file_path in files_to_process {
+        if state.cancel.load(Ordering::SeqCst) {
+            break;
+        }
         let permit = sem.clone().acquire_owned().await.unwrap();
         let win = window.clone();
         let cancel_flag = state.cancel.clone();

src/App.tsx

@@ -466,7 +466,9 @@ const SingleFileTab = ({ filePath, setFilePath, selectedAlgorithms, handleAlgori
         applyHashResults(mergedResults);
       } catch (error) {
         console.error('Hash calculation failed:', error);
-        showAlert('Error', 'Hash calculation failed: ' + error);
+        if (error !== "Cancelled") {
+          showAlert('Error', 'Hash calculation failed: ' + error);
+        }
       } finally {
         setIsHashing(false);
         setProgress(null);
@@ -482,11 +484,13 @@ const SingleFileTab = ({ filePath, setFilePath, selectedAlgorithms, handleAlgori
     (async () => {
       unlisten = await listen('hash-progress', (event: any) => {
         const payload = event.payload as any;
-        setProgress({ 
-          percent: payload.percent || 0, 
-          bytes_read: payload.bytes_read || 0, 
-          total: payload.total || 0 
-        });
+        if (payload.file === filePath) {
+          setProgress({ 
+            percent: payload.percent || 0, 
+            bytes_read: payload.bytes_read || 0, 
+            total: payload.total || 0 
+          });
+        }
       });
     })();
 
@@ -495,7 +499,7 @@ const SingleFileTab = ({ filePath, setFilePath, selectedAlgorithms, handleAlgori
         unlisten.then((f: any) => f());
       }
     };
-  }, []);
+  }, [filePath]);
 
   const handleSaveReport = async () => {
     if (!filePath) {
@@ -885,6 +889,7 @@ const FolderScanTab = ({ folderPath, setFolderPath, selectedAlgorithms, handleAl
   const [files, setFiles] = useState<any[]>([]);
   const [includeSubfolders, setIncludeSubfolders] = useState(true);
   const [includeHidden, setIncludeHidden] = useState(false);
+  const [isScanning, setIsScanning] = useState(false);
 
   const handleFolderSelect = async () => {
     const selected = await openDialog({
@@ -905,13 +910,21 @@ const FolderScanTab = ({ folderPath, setFolderPath, selectedAlgorithms, handleAl
       return;
     }
 
-    const scannedFiles = await invoke("scan_folder", { 
-      folderPath, 
-      includeSubfolders, 
-      includeHidden,
-      algorithms 
-    });
-    setFiles(scannedFiles as any[]);
+    setIsScanning(true);
+    setFiles([]);
+    try {
+      const scannedFiles = await invoke("scan_folder", { 
+        folderPath, 
+        includeSubfolders, 
+        includeHidden,
+        algorithms 
+      });
+      setFiles(scannedFiles as any[]);
+    } catch (e) {
+      if (e !== "Cancelled") showAlert('Error', `Folder scan failed: ${e}`);
+    } finally {
+      setIsScanning(false);
+    }
   };
 
   const handleSaveReport = async () => {
@@ -995,7 +1008,13 @@ const FolderScanTab = ({ folderPath, setFolderPath, selectedAlgorithms, handleAl
             <FormControlLabel control={<Checkbox checked={includeHidden} onChange={() => setIncludeHidden(!includeHidden)} />} label="Include Hidden Files" />
         </Box>
 
-        <Button variant="contained" onClick={handleScan} fullWidth sx={{ mt: 2 }}>Scan Folder</Button>
+        <Box sx={{ mt: 2, display: 'flex', gap: 1 }}>
+          <Button variant="contained" onClick={handleScan} fullWidth disabled={isScanning}>Scan Folder</Button>
+          {isScanning && (
+            <Button variant="outlined" color="error" onClick={() => invoke('cancel_hashing')}>Cancel</Button>
+          )}
+        </Box>
+        {isScanning && <LinearProgress sx={{ mt: 2 }} />}
 
         <TableContainer component={Paper} sx={{ mt: 2 }}>
             <Table>