A bunch of changes

bagheeraview.py

@@ -68,7 +68,8 @@ from constants import (
 )
 import constants
 from settings import SettingsDialog
-from imagescanner import CacheCleaner, ImageScanner, ThumbnailCache, ThumbnailGenerator
+from imagescanner import (CacheCleaner, ImageScanner, ThumbnailCache,
+                          ThumbnailGenerator, ThreadPoolManager)
 from imageviewer import ImageViewer
 from propertiesdialog import PropertiesDialog
 from widgets import (
@@ -903,13 +904,14 @@ class MainWindow(QMainWindow):
     scanners and individual image viewer windows.
     """
 
-    def __init__(self, cache, args):
+    def __init__(self, cache, args, thread_pool_manager):
         """
         Initializes the MainWindow.
 
         Args:
             cache (ThumbnailCache): The shared thumbnail cache instance.
             args (list): Command-line arguments passed to the application.
+            thread_pool_manager (ThreadPoolManager): The shared thread pool manager.
         """
         super().__init__()
         self.cache = cache
@@ -917,6 +919,7 @@ class MainWindow(QMainWindow):
         self.set_app_icon()
 
         self.viewer_shortcuts = {}
+        self.thread_pool_manager = thread_pool_manager
         self.full_history = []
         self.history = []
         self.current_thumb_size = THUMBNAILS_DEFAULT_SIZE
@@ -1320,12 +1323,14 @@ class MainWindow(QMainWindow):
     def _on_scroll_interaction(self, value):
         """Pauses scanning during scroll to keep UI fluid."""
         if self.scanner and self.scanner.isRunning():
+            self.thread_pool_manager.set_user_active(True)
             self.scanner.set_paused(True)
             self.resume_scan_timer.start()
 
     def _resume_scanning(self):
         """Resumes scanning after interaction pause."""
         if self.scanner:
+            self.thread_pool_manager.set_user_active(False)
             # Prioritize currently visible images
             visible_paths = self.get_visible_image_paths()
             self.scanner.prioritize(visible_paths)
@@ -1676,6 +1681,7 @@ class MainWindow(QMainWindow):
 
             # Trigger a repaint to apply other color changes like filename color
             self._apply_global_stylesheet()
+            self.thread_pool_manager.update_default_thread_count()
             self.thumbnail_view.updateGeometries()
             self.thumbnail_view.viewport().update()
 
@@ -2352,6 +2358,7 @@ class MainWindow(QMainWindow):
 
         self.is_cleaning = False
         self.scanner = ImageScanner(self.cache, paths, is_file_list=self._scan_all,
+                                    thread_pool_manager=self.thread_pool_manager,
                                     viewers=self.viewers)
         if self._is_loading_all:
             self.scanner.set_auto_load(True)
@@ -3516,7 +3523,8 @@ class MainWindow(QMainWindow):
         if not paths:
             return
 
-        self.thumbnail_generator = ThumbnailGenerator(self.cache, paths, size)
+        self.thumbnail_generator = ThumbnailGenerator(
+            self.cache, paths, size, self.thread_pool_manager)
         self.thumbnail_generator.generation_complete.connect(
             self.on_high_res_generation_finished)
         self.thumbnail_generator.progress.connect(
@@ -3983,7 +3991,8 @@ class MainWindow(QMainWindow):
 
         # Create a ThumbnailGenerator to regenerate the thumbnail
         size = self._get_tier_for_size(self.current_thumb_size)
-        self.thumbnail_generator = ThumbnailGenerator(self.cache, [path], size)
+        self.thumbnail_generator = ThumbnailGenerator(
+            self.cache, [path], size, self.thread_pool_manager)
         self.thumbnail_generator.generation_complete.connect(
             self.on_high_res_generation_finished)
         self.thumbnail_generator.progress.connect(
@@ -4362,6 +4371,7 @@ def main():
     # Increase QPixmapCache limit (default is usually small, ~10MB) to ~100MB
     QPixmapCache.setCacheLimit(102400)
 
+    thread_pool_manager = ThreadPoolManager()
     cache = ThumbnailCache()
 
     args = [a for a in sys.argv[1:] if a != "--x11"]
@@ -4370,7 +4380,7 @@ def main():
         if path.startswith("file:/"):
             path = path[6:]
 
-    win = MainWindow(cache, args)
+    win = MainWindow(cache, args, thread_pool_manager)
     shortcut_controller = AppShortcutController(win)
     win.shortcut_controller = shortcut_controller
     app.installEventFilter(shortcut_controller)

changelog.txt

@@ -3,10 +3,11 @@ v0.9.11 -
 · Añadida una nueva área llamada Body.
 · Refactorizaciones, optimizaciones y cambios a saco.
 
+Add a `shutdown` signal or method to `ScannerWorker` to allow cleaner cancellation of long-running tasks like `generate_thumbnail`.
+Implement a mechanism to dynamically adjust the thread pool size based on system load or user activity.
 
-
+Implement a mechanism to monitor system CPU load and adjust the thread pool size accordingly.
-
+Refactor the `ThreadPoolManager` to be a QObject and emit signals when the thread count changes.
-Refactor the `ImageScanner` to use a thread pool for parallel thumbnail generation for faster loading.
 
 Implement a "Comparison" mode to view 2 or 4 images side-by-side in the viewer.
 

constants.py

@@ -168,11 +168,6 @@ if importlib.util.find_spec("mediapipe") is not None:
 HAVE_FACE_RECOGNITION = importlib.util.find_spec("face_recognition") is not None
 
 HAVE_BAGHEERASEARCH_LIB = False
-try:
-    import bagheera_search_lib
-    HAVE_BAGHEERASEARCH_LIB = True
-except ImportError:
-    pass
 
 MEDIAPIPE_FACE_MODEL_PATH = os.path.join(CONFIG_DIR,
                                          "blaze_face_short_range.tflite")

imagescanner.py

@@ -28,9 +28,10 @@ import collections
 from pathlib import Path
 from contextlib import contextmanager
 import lmdb
-from PySide6.QtCore import (QObject, QThread, Signal, QMutex, QReadWriteLock, QSize,
+from PySide6.QtCore import (
-                            QWaitCondition, QByteArray, QBuffer, QIODevice, Qt, QTimer,
+    QObject, QThread, Signal, QMutex, QReadWriteLock, QSize, QSemaphore, QWaitCondition,
-                            QRunnable, QThreadPool)
+    QByteArray, QBuffer, QIODevice, Qt, QTimer, QRunnable, QThreadPool, QFile
+)
 from PySide6.QtGui import QImage, QImageReader, QImageIOHandler
 
 from constants import (
@@ -49,9 +50,192 @@ if HAVE_BAGHEERASEARCH_LIB:
 logger = logging.getLogger(__name__)
 
 
-def generate_thumbnail(path, size):
+class ThreadPoolManager:
+    """Manages a global QThreadPool to dynamically adjust thread count."""
+    def __init__(self):
+        self.pool = QThreadPool()
+        self.default_thread_count = APP_CONFIG.get(
+            "generation_threads",
+            SCANNER_SETTINGS_DEFAULTS.get("generation_threads", 4)
+        )
+        self.pool.setMaxThreadCount(self.default_thread_count)
+        self.is_user_active = False
+        logger.info(f"ThreadPoolManager initialized with {self.default_thread_count} threads.")
+
+    def get_pool(self):
+        """Returns the managed QThreadPool instance."""
+        return self.pool
+
+    def set_user_active(self, active):
+        """
+        Adjusts thread count based on user activity.
+
+        Args:
+            active (bool): True if the user is interacting with the UI.
+        """
+        if active == self.is_user_active:
+            return
+        self.is_user_active = active
+        if active:
+            # User is active, reduce threads to 1 to prioritize UI responsiveness.
+            self.pool.setMaxThreadCount(1)
+            logger.debug("User is active, reducing thread pool to 1.")
+        else:
+            # User is idle, restore to default thread count.
+            self.pool.setMaxThreadCount(self.default_thread_count)
+            logger.debug(f"User is idle, restoring thread pool to {self.default_thread_count}.")
+
+    def update_default_thread_count(self):
+        """Updates the default thread count from application settings."""
+        self.default_thread_count = APP_CONFIG.get(
+            "generation_threads",
+            SCANNER_SETTINGS_DEFAULTS.get("generation_threads", 4)
+        )
+        # Only apply if not in a user-active (low-thread) state.
+        if not self.is_user_active:
+            self.pool.setMaxThreadCount(self.default_thread_count)
+        logger.info(f"Default thread count updated to {self.default_thread_count}.")
+
+
+class ScannerWorker(QRunnable):
+    """
+    Worker to process a single image in a thread pool.
+    Handles thumbnail retrieval/generation and metadata loading.
+    """
+    def __init__(self, cache, path, target_sizes=None, load_metadata=True,
+                 signal_emitter=None, semaphore=None):
+        super().__init__()
+        self.cache = cache
+        self.path = path
+        self.target_sizes = target_sizes
+        self.load_metadata_flag = load_metadata
+        self.emitter = signal_emitter
+        self.semaphore = semaphore
+        self._is_cancelled = False
+        # Result will be (path, thumb, mtime, tags, rating, inode, dev) or None
+        self.result = None
+
+    def shutdown(self):
+        """Marks the worker as cancelled."""
+        self._is_cancelled = True
+
+    def run(self):
+        from constants import SCANNER_GENERATE_SIZES
+
+        sizes_to_check = self.target_sizes if self.target_sizes is not None \
+            else SCANNER_GENERATE_SIZES
+
+        if self._is_cancelled:
+            if self.semaphore:
+                self.semaphore.release()
+            return
+
+        fd = None
+        try:
+            # Optimize: Open file once to reuse FD for stat and xattrs
+            fd = os.open(self.path, os.O_RDONLY)
+            stat_res = os.fstat(fd)
+            curr_mtime = stat_res.st_mtime
+            curr_inode = stat_res.st_ino
+            curr_dev = stat_res.st_dev
+
+            smallest_thumb_for_signal = None
+            min_size = min(sizes_to_check) if sizes_to_check else 0
+
+            # Ensure required thumbnails exist
+            for size in sizes_to_check:
+                if self._is_cancelled:
+                    return
+
+                # Check if a valid thumbnail for this size exists
+                thumb, mtime = self.cache.get_thumbnail(self.path, size,
+                                                        curr_mtime=curr_mtime,
+                                                        inode=curr_inode,
+                                                        device_id=curr_dev)
+                if not thumb or mtime != curr_mtime:
+                    # Use generation lock to prevent multiple threads generating
+                    with self.cache.generation_lock(
+                            self.path, size, curr_mtime,
+                            curr_inode, curr_dev) as should_gen:
+                        if self._is_cancelled:
+                            return
+
+                        if should_gen:
+                            # I am the owner, I generate the thumbnail
+                            new_thumb = generate_thumbnail(self.path, size, fd=fd)
+                            if self._is_cancelled:
+                                return
+                            if new_thumb and not new_thumb.isNull():
+                                self.cache.set_thumbnail(
+                                    self.path, new_thumb, curr_mtime, size,
+                                    inode=curr_inode, device_id=curr_dev, block=True)
+                                if size == min_size:
+                                    smallest_thumb_for_signal = new_thumb
+                        else:
+                            # Another thread generated it, re-fetch
+                            if size == min_size:
+                                re_thumb, _ = self.cache.get_thumbnail(
+                                    self.path, size, curr_mtime=curr_mtime,
+                                    inode=curr_inode, device_id=curr_dev,
+                                    async_load=False)
+                                smallest_thumb_for_signal = re_thumb
+                elif size == min_size:
+                    # valid thumb exists, use it for signal
+                    smallest_thumb_for_signal = thumb
+
+            tags = []
+            rating = 0
+            if self.load_metadata_flag:
+                tags, rating = self._load_metadata(fd)
+            self.result = (self.path, smallest_thumb_for_signal,
+                           curr_mtime, tags, rating, curr_inode, curr_dev)
+        except Exception as e:
+            logger.error(f"Error processing image {self.path}: {e}")
+            self.result = None
+        finally:
+            if fd is not None:
+                try:
+                    os.close(fd)
+                except OSError:
+                    pass
+            if self.emitter:
+                self.emitter.emit_progress()
+            if self.semaphore:
+                self.semaphore.release()
+
+    def _load_metadata(self, path_or_fd):
+        """Loads tag and rating data for a path or file descriptor."""
+        tags = []
+        raw_tags = XattrManager.get_attribute(path_or_fd, XATTR_NAME)
+        if raw_tags:
+            tags = sorted(list(set(t.strip()
+                                   for t in raw_tags.split(',') if t.strip())))
+
+        raw_rating = XattrManager.get_attribute(path_or_fd, RATING_XATTR_NAME, "0")
+        try:
+            rating = int(raw_rating)
+        except ValueError:
+            rating = 0
+        return tags, rating
+
+
+def generate_thumbnail(path, size, fd=None):
     """Generates a QImage thumbnail for a given path and size."""
     try:
+        qfile = None
+        if fd is not None:
+            try:
+                # Ensure we are at the beginning of the file
+                os.lseek(fd, 0, os.SEEK_SET)
+                qfile = QFile()
+                if qfile.open(fd, QIODevice.ReadOnly, QFile.DontCloseHandle):
+                    reader = QImageReader(qfile)
+                else:
+                    qfile = None
+                    reader = QImageReader(path)
+            except OSError:
+                reader = QImageReader(path)
+        else:
             reader = QImageReader(path)
 
         # Optimization: Instruct the image decoder to scale while reading.
@@ -1046,45 +1230,6 @@ class CacheCleaner(QThread):
         self.finished_clean.emit(removed_count)
 
 
-class ThumbnailRunnable(QRunnable):
-    """Runnable task to generate a single thumbnail."""
-    def __init__(self, cache, path, size, signal_emitter):
-        super().__init__()
-        self.cache = cache
-        self.path = path
-        self.size = size
-        self.emitter = signal_emitter
-
-    def run(self):
-        try:
-            # Optimization: Single stat call per file
-            stat_res = os.stat(self.path)
-            curr_mtime = stat_res.st_mtime
-            inode = stat_res.st_ino
-            dev = stat_res.st_dev
-
-            # Check cache first to avoid expensive generation
-            thumb, mtime = self.cache.get_thumbnail(
-                self.path, self.size, curr_mtime=curr_mtime,
-                inode=inode, device_id=dev, async_load=False)
-
-            if not thumb or mtime != curr_mtime:
-                # Use the generation lock to coordinate
-                with self.cache.generation_lock(
-                        self.path, self.size, curr_mtime, inode, dev) as should_gen:
-                    if should_gen:
-                        # I am the owner, I generate the thumbnail
-                        new_thumb = generate_thumbnail(self.path, self.size)
-                        if new_thumb and not new_thumb.isNull():
-                            self.cache.set_thumbnail(
-                                self.path, new_thumb, curr_mtime, self.size,
-                                inode=inode, device_id=dev, block=True)
-        except Exception as e:
-            logger.error(f"Error generating thumbnail for {self.path}: {e}")
-        finally:
-            self.emitter.emit_progress()
-
-
 class ThumbnailGenerator(QThread):
     """
     Background thread to generate thumbnails for a specific size for a list of
@@ -1100,31 +1245,35 @@ class ThumbnailGenerator(QThread):
         def emit_progress(self):
             self.progress_tick.emit()
 
-    def __init__(self, cache, paths, size):
+    def __init__(self, cache, paths, size, thread_pool_manager):
         super().__init__()
         self.cache = cache
         self.paths = paths
         self.size = size
         self._abort = False
+        self.thread_pool_manager = thread_pool_manager
+        self._workers = []
+        self._workers_mutex = QMutex()
 
     def stop(self):
         """Stops the worker thread gracefully."""
         self._abort = True
+        self._workers_mutex.lock()
+        for worker in self._workers:
+            worker.shutdown()
+        self._workers_mutex.unlock()
         self.wait()
 
     def run(self):
         """
         Main execution loop. Uses a thread pool to process paths in parallel.
         """
-        pool = QThreadPool()
+        pool = self.thread_pool_manager.get_pool()
-        max_threads = APP_CONFIG.get(
-            "generation_threads",
-            SCANNER_SETTINGS_DEFAULTS.get("generation_threads", 4))
-        pool.setMaxThreadCount(max_threads)
 
         emitter = self.SignalEmitter()
         processed_count = 0
         total = len(self.paths)
+        sem = QSemaphore(0)
 
         def on_tick():
             nonlocal processed_count
@@ -1138,13 +1287,33 @@ class ThumbnailGenerator(QThread):
         # The signal/slot mechanism handles thread safety automatically.
         emitter.progress_tick.connect(on_tick, Qt.QueuedConnection)
 
+        started_count = 0
         for path in self.paths:
             if self._abort:
                 break
-            runnable = ThumbnailRunnable(self.cache, path, self.size, emitter)
+            runnable = ScannerWorker(self.cache, path, target_sizes=[self.size],
-            pool.start(runnable)
+                                     load_metadata=False, signal_emitter=emitter,
+                                     semaphore=sem)
+            runnable.setAutoDelete(False)
 
-        pool.waitForDone()
+            self._workers_mutex.lock()
+            if self._abort:
+                self._workers_mutex.unlock()
+                break
+            self._workers.append(runnable)
+            self._workers_mutex.unlock()
+
+            pool.start(runnable)
+            started_count += 1
+
+        if started_count > 0:
+            sem.acquire(started_count)
+
+        self._workers_mutex.lock()
+        self._workers.clear()
+        self._workers_mutex.unlock()
+
+        if not self._abort:
             self.generation_complete.emit()
 
 
@@ -1159,8 +1328,8 @@ class ImageScanner(QThread):
     progress_percent = Signal(int)
     finished_scan = Signal(int)  # Total images found
     more_files_available = Signal(int, int)  # Last loaded index, remainder
-
+    def __init__(self, cache, paths, is_file_list=False, viewers=None,
-    def __init__(self, cache, paths, is_file_list=False, viewers=None):
+                 thread_pool_manager=None):
         # is_file_list is not used
         if not paths or not isinstance(paths, (list, tuple)):
             logger.warning("ImageScanner initialized with empty or invalid paths")
@@ -1168,6 +1337,7 @@ class ImageScanner(QThread):
         super().__init__()
         self.cache = cache
         self.all_files = []
+        self.thread_pool_manager = thread_pool_manager
         self._viewers = viewers
         self._seen_files = set()
         self._is_file_list = is_file_list
@@ -1196,12 +1366,23 @@ class ImageScanner(QThread):
         self.pending_tasks = []
         self._priority_queue = collections.deque()
         self._processed_paths = set()
+        self._current_workers = []
+        self._current_workers_mutex = QMutex()
 
         # Initial load
         self.pending_tasks.append((0, APP_CONFIG.get(
             "scan_batch_size", SCANNER_SETTINGS_DEFAULTS["scan_batch_size"])))
         self._last_update_time = 0
 
+        if self.thread_pool_manager:
+            self.pool = self.thread_pool_manager.get_pool()
+        else:
+            self.pool = QThreadPool()
+            max_threads = APP_CONFIG.get(
+                "generation_threads",
+                SCANNER_SETTINGS_DEFAULTS.get("generation_threads", 4))
+            self.pool.setMaxThreadCount(max_threads)
+
         logger.info(f"ImageScanner initialized with {len(paths)} paths")
 
     def set_auto_load(self, enabled):
@@ -1455,65 +1636,110 @@ class ImageScanner(QThread):
             self.finished_scan.emit(self.count)
             return
 
+        if self.thread_pool_manager:
+            max_threads = self.thread_pool_manager.default_thread_count
+        else:
+            max_threads = APP_CONFIG.get(
+                "generation_threads",
+                SCANNER_SETTINGS_DEFAULTS.get("generation_threads", 4))
+            self.pool.setMaxThreadCount(max_threads)
+
         images_loaded = 0
         batch = []
         while i < len(self.all_files):
 
             if not self._is_running:
                 return
-            self.msleep(1)  # Force yield to UI thread per item
 
             while self._paused and self._is_running:
                 self.msleep(100)
 
-            # 1. Check priority queue first
+            # Collect paths for this chunk to process in parallel
-            priority_path = None
+            chunk_size = max_threads * 2
+            tasks = []  # List of (path, is_from_priority_queue)
+
+            # 1. Drain priority queue up to chunk size
             self.mutex.lock()
-            while self._priority_queue:
+            while len(tasks) < chunk_size and self._priority_queue:
                 p = self._priority_queue.popleft()
                 if p not in self._processed_paths and p in self._seen_files:
-                    priority_path = p
+                    tasks.append((p, True))
-                    break
             self.mutex.unlock()
 
-            # 2. Determine file to process
+            # 2. Fill remaining chunk space with sequential files
-            if priority_path:
+            temp_i = i
-                f_path = priority_path
+            while len(tasks) < chunk_size and temp_i < len(self.all_files):
-                # Don't increment 'i' yet, we are processing out of order
+                p = self.all_files[temp_i]
-            else:
+                # Skip if already processed (e.g. via priority earlier)
-                f_path = self.all_files[i]
+                if p not in self._processed_paths \
-                i += 1  # Only advance sequential index if processing sequentially
+                   and Path(p).suffix.lower() in IMAGE_EXTENSIONS:
+                    tasks.append((p, False))
+                temp_i += 1
 
-            if f_path not in self._processed_paths \
+            if not tasks:
-               and Path(f_path).suffix.lower() in IMAGE_EXTENSIONS:
+                # If no tasks found but still have files (e.g. all skipped extensions),
-                # Pass the batch list to store result instead of emitting immediately
+                # update index and continue loop
-                was_loaded = self._process_single_image(f_path, batch)
+                i = temp_i
+                continue
+
+            # Submit tasks to thread pool
+            sem = QSemaphore(0)
+            runnables = []
+
+            self._current_workers_mutex.lock()
+            if not self._is_running:
+                self._current_workers_mutex.unlock()
+                return
+
+            for f_path, _ in tasks:
+                r = ScannerWorker(self.cache, f_path, semaphore=sem)
+                r.setAutoDelete(False)
+                runnables.append(r)
+                self._current_workers.append(r)
+                self.pool.start(r)
+            self._current_workers_mutex.unlock()
+
+            # Wait only for this chunk to finish using semaphore
+            sem.acquire(len(runnables))
+
+            self._current_workers_mutex.lock()
+            self._current_workers.clear()
+            self._current_workers_mutex.unlock()
+
+            if not self._is_running:
+                return
+
+            # Process results
+            for r in runnables:
+                if r.result:
+                    self._processed_paths.add(r.path)
+                    batch.append(r.result)
+                    self.count += 1
+                    images_loaded += 1
+
+            # Clean up runnables
+            runnables.clear()
+
+            # Advance sequential index
+            i = temp_i
 
             # Emit batch if size is enough (responsiveness optimization)
-                # Dynamic batching: Start small for instant feedback.
-                # Keep batches small enough to prevent UI starvation during rapid cache
-                # reads.
             if self.count <= 100:
                 target_batch_size = 20
             else:
                 target_batch_size = 200
 
             if len(batch) >= target_batch_size:
-
                 self.images_found.emit(batch)
                 batch = []
-                    # Yield briefly to let the main thread process the emitted batch
+                self.msleep(10)  # Yield to UI
-                    # (update UI), preventing UI freeze during fast cache reading.
-                    self.msleep(10)
 
-                if was_loaded:
+            # Check if loading limit reached
-                    self._processed_paths.add(f_path)
-                    images_loaded += 1
             if images_loaded >= to_load and to_load > 0:
                 if batch:  # Emit remaining items
                     self.images_found.emit(batch)
 
-                        next_index = i + 1
+                next_index = i
                 total_files = len(self.all_files)
                 self.index = next_index
                 self.progress_msg.emit(UITexts.LOADED_PARTIAL.format(
@@ -1547,88 +1773,17 @@ class ImageScanner(QThread):
         self.progress_percent.emit(100)
         self.finished_scan.emit(self.count)
 
-    def _load_metadata(self, path_or_fd):
-        """Loads tag and rating data for a path or file descriptor."""
-        tags = []
-
-        raw_tags = XattrManager.get_attribute(path_or_fd, XATTR_NAME)
-        if raw_tags:
-            tags = sorted(list(set(t.strip()
-                                   for t in raw_tags.split(',') if t.strip())))
-
-        raw_rating = XattrManager.get_attribute(path_or_fd, RATING_XATTR_NAME, "0")
-        try:
-            rating = int(raw_rating)
-        except ValueError:
-            rating = 0
-        return tags, rating
-
-    def _process_single_image(self, f_path, batch_list):
-        from constants import SCANNER_GENERATE_SIZES
-
-        fd = None
-        try:
-            # Optimize: Open file once to reuse FD for stat and xattrs
-            fd = os.open(f_path, os.O_RDONLY)
-            stat_res = os.fstat(fd)
-            curr_mtime = stat_res.st_mtime
-            curr_inode = stat_res.st_ino
-            curr_dev = stat_res.st_dev
-
-            smallest_thumb_for_signal = None
-
-            # Ensure required thumbnails exist
-            for size in SCANNER_GENERATE_SIZES:
-                # Check if a valid thumbnail for this size exists
-                thumb, mtime = self.cache.get_thumbnail(f_path, size,
-                                                        curr_mtime=curr_mtime,
-                                                        inode=curr_inode,
-                                                        device_id=curr_dev)
-                if not thumb or mtime != curr_mtime:
-                    # Use generation lock to prevent multiple threads generating the
-                    # same thumb
-                    with self.cache.generation_lock(
-                            f_path, size, curr_mtime,
-                            curr_inode, curr_dev) as should_gen:
-                        if should_gen:
-                            # I am the owner, I generate the thumbnail
-                            new_thumb = generate_thumbnail(f_path, size)
-                            if new_thumb and not new_thumb.isNull():
-                                self.cache.set_thumbnail(
-                                    f_path, new_thumb, curr_mtime, size,
-                                    inode=curr_inode, device_id=curr_dev, block=True)
-                                if size == min(SCANNER_GENERATE_SIZES):
-                                    smallest_thumb_for_signal = new_thumb
-                        else:
-                            # Another thread generated it, re-fetch to use it for the
-                            # signal
-                            if size == min(SCANNER_GENERATE_SIZES):
-                                re_thumb, _ = self.cache.get_thumbnail(
-                                    f_path, size, curr_mtime=curr_mtime,
-                                    inode=curr_inode, device_id=curr_dev,
-                                    async_load=False)
-                                smallest_thumb_for_signal = re_thumb
-                elif size == min(SCANNER_GENERATE_SIZES):
-                    # valid thumb exists, use it for signal
-                    smallest_thumb_for_signal = thumb
-
-            tags, rating = self._load_metadata(fd)
-            batch_list.append((f_path, smallest_thumb_for_signal,
-                               curr_mtime, tags, rating, curr_inode, curr_dev))
-            self.count += 1
-            return True
-        except Exception as e:
-            logger.error(f"Error processing image {f_path}: {e}")
-            return False
-        finally:
-            if fd is not None:
-                try:
-                    os.close(fd)
-                except OSError:
-                    pass
-
     def stop(self):
+        logger.info("ImageScanner stop requested")
         self._is_running = False
+
+        # Cancel currently running workers in the active batch
+        self._current_workers_mutex.lock()
+        for worker in self._current_workers:
+            worker.shutdown()
+        self._current_workers_mutex.unlock()
+
+        # Wake up the condition variable
         self.mutex.lock()
         self.condition.wakeAll()
         self.mutex.unlock()