Improve stability issues

imagescanner.py

@@ -32,7 +32,7 @@ from PySide6.QtCore import (
     QObject, QThread, Signal, QMutex, QReadWriteLock, QSize, QSemaphore, QWaitCondition,
     QByteArray, QBuffer, QIODevice, Qt, QTimer, QRunnable, QThreadPool, QFile
 )
-from PySide6.QtGui import QImage, QImageReader, QImageIOHandler
+from PySide6.QtGui import QImage, QImageReader, QImageIOHandler, QIcon
 from PySide6.QtWidgets import QApplication
 
 from constants import (
@@ -134,11 +134,11 @@ class ScannerWorker(QRunnable):
         sizes_to_check = self.target_sizes if self.target_sizes is not None \
             else SCANNER_GENERATE_SIZES
 
+        fd = None
         try:
             if self._is_cancelled:
                 return
 
-            fd = None
             # Optimize: Open file once to reuse FD for stat and xattrs
             fd = os.open(self.path, os.O_RDONLY)
             stat_res = os.fstat(fd)
@@ -196,8 +196,11 @@ class ScannerWorker(QRunnable):
                 tags, rating = res_meta.tags, res_meta.rating
             self.result = (self.path, smallest_thumb_for_signal,
                            curr_mtime, tags, rating, curr_inode, curr_dev)
+        except (FileNotFoundError, PermissionError) as e:
+            logger.debug(f"Skipping {self.path} due to access issue: {e}")
+            self.result = None
         except Exception as e:
-            logger.error(f"Error processing image {self.path}: {e}")
+            logger.warning(f"Unexpected error processing image {self.path}: {e}")
             self.result = None
         finally:
             if fd is not None:
@@ -265,7 +268,7 @@ def generate_thumbnail(path, size, fd=None):
         # better quality for upscaling.
         return img.scaled(size, size, Qt.KeepAspectRatio, Qt.SmoothTransformation)
     except Exception as e:
-        logger.error(f"Error generating thumbnail for {path}: {e}")
+        logger.debug(f"Could not generate thumbnail for {path}: {e}")
         return None
 
 
@@ -523,10 +526,19 @@ class ThumbnailCache(QObject):
         self._db_lock = QMutex()  # Lock specifically for _db_handles access
         self._db_handles = {}  # Cache for LMDB database handles (dbi)
         self._cancel_loading = False
+        self._broken_cache = {}  # (dev, inode, size) -> (mtime, error_msg)
         self._cache_bytes_size = 0
         self._cache_writer = None
         self._cache_loader = None
 
+        # Pre-generate broken images for standard tiers in the main thread
+        self._broken_images = {}
+        for size in THUMBNAIL_SIZES:
+            icon = QIcon.fromTheme("image-missing",
+                                   QIcon.fromTheme("broken-image",
+                                                   QIcon.fromTheme("dialog-error")))
+            self._broken_images[size] = icon.pixmap(size, size).toImage()
+
         self.lmdb_open()
 
     def lmdb_open(self):
@@ -739,6 +751,21 @@ class ThumbnailCache(QObject):
             return 256
         return 512
 
+    def mark_broken(self, path, size, mtime, inode, dev_id, error_msg):
+        """Marks a thumbnail load as failed with a message."""
+        key = (dev_id, struct.pack('Q', inode) if inode is not None else None, size)
+        with self._write_lock():
+            self._broken_cache[key] = (mtime, error_msg)
+
+    def get_broken_info(self, path, size, mtime, inode, dev_id):
+        """Returns the error message if a thumbnail is known to have failed, else None."""
+        key = (dev_id, struct.pack('Q', inode) if inode is not None else None, size)
+        with self._read_lock():
+            info = self._broken_cache.get(key)
+            if info and info[0] == mtime:
+                return info[1]
+            return None
+
     def _resolve_file_identity(self, path, curr_mtime, inode, device_id):
         """Helper to resolve file mtime, device, and inode."""
         mtime = curr_mtime
@@ -859,6 +886,11 @@ class ThumbnailCache(QObject):
         if mtime is None:
             return EMPTY_THUMBNAIL
 
+        # Check if known to be broken
+        broken_msg = self.get_broken_info(path, target_tier, mtime, inode, device_id)
+        if broken_msg:
+            return ThumbnailResult(self._broken_images.get(target_tier), mtime, target_tier)
+
         best_img, best_mtime, best_tier = None, 0, 0
 
         with self._read_lock():
@@ -1455,13 +1487,14 @@ class ImageScanner(QThread):
     more_files_available = Signal(int, int)  # Last loaded index, remainder
 
     def __init__(self, cache, paths, is_file_list=False, viewers=None,
-                 thread_pool_manager=None):
+                 thread_pool_manager=None, target_sizes=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")
             paths = []
         super().__init__()
         self.cache = cache
+        self.target_sizes = target_sizes
         self.all_files = []
         self.thread_pool_manager = thread_pool_manager
         self._viewers = viewers
@@ -1818,7 +1851,7 @@ class ImageScanner(QThread):
                 return
 
             for f_path, _ in tasks:
-                r = ScannerWorker(self.cache, f_path, semaphore=sem)
+                r = ScannerWorker(self.cache, f_path, semaphore=sem, target_sizes=self.target_sizes)
                 r.setAutoDelete(False)
                 runnables.append(r)
                 self._current_workers.append(r)