Fix store FD exhaustion: run cover/date loaders one at a time

app/gui.py

@@ -1831,6 +1831,8 @@ class StorePage(QWidget):
         self._lib_cover = {}  # norm -> (release_id, system)
         self._psp_norm = set()   # norm of library items installed on the PSP
         self._cover_attempted = set()
+        self._cover_busy = False
+        self._date_busy = False
         self._generation = 0
         self._scan_gen = 0
         self._meta_gen = 0
@@ -2180,6 +2182,8 @@ class StorePage(QWidget):
         self._cover_next = 0
         self._date_queue = []
         self._date_next = 0
+        self._cover_busy = False
+        self._date_busy = False
         self._cover_attempted.clear()
         self._placeholder = QIcon(_placeholder_pixmap(self.ICON_W, self.ICON_H))
 
@@ -2305,13 +2309,14 @@ class StorePage(QWidget):
         self._load_date_batch(self.DATE_BATCH)
 
     def _load_cover_batch(self, n):
-        if self._closing or not self._cover_queue:
+        if self._closing or not self._cover_queue or self._cover_busy:
             return
         end = min(self._cover_next + n, len(self._cover_queue))
         if self._cover_next >= end:
             return
         tasks = self._cover_queue[self._cover_next:end]
         self._cover_next = end
+        self._cover_busy = True
         self._start_cover_loader(self._generation, tasks)
 
     def _active_scrollbar(self):
@@ -2342,13 +2347,14 @@ class StorePage(QWidget):
             self._fill_timer.start()
 
     def _load_date_batch(self, n):
-        if self._closing or not self._date_queue:
+        if self._closing or not self._date_queue or self._date_busy:
             return
         end = min(self._date_next + n, len(self._date_queue))
         if self._date_next >= end:
             return
         tasks = self._date_queue[self._date_next:end]
         self._date_next = end
+        self._date_busy = True
         self._start_date_loader(self._generation, tasks)
 
     def _start_date_loader(self, gen, tasks):
@@ -2359,12 +2365,22 @@ class StorePage(QWidget):
         loader.moveToThread(thread)
         thread.started.connect(loader.run)
         loader.loaded.connect(self._on_date_loaded)
+        loader.finished.connect(self._on_date_batch_done)
         loader.finished.connect(thread.quit)
         thread.finished.connect(self._on_thread_finished)
         self._threads.append(thread)
         self._loaders.append(loader)
         thread.start()
 
+    def _on_date_batch_done(self):
+        if self._closing:
+            return
+        loader = self.sender()
+        if getattr(loader, "gen", None) != self._generation:
+            return
+        self._date_busy = False
+        self._load_date_batch(self.DATE_BATCH)
+
     def _on_date_loaded(self, gen, row, date):
         if self._closing or gen != self._generation or not date:
             return
@@ -2382,12 +2398,22 @@ class StorePage(QWidget):
         loader.moveToThread(thread)
         thread.started.connect(loader.run)
         loader.loaded.connect(self._on_cover_loaded)
+        loader.finished.connect(self._on_cover_batch_done)
         loader.finished.connect(thread.quit)
         thread.finished.connect(self._on_thread_finished)
         self._threads.append(thread)
         self._loaders.append(loader)
         thread.start()
 
+    def _on_cover_batch_done(self):
+        if self._closing:
+            return
+        loader = self.sender()
+        if getattr(loader, "gen", None) != self._generation:
+            return
+        self._cover_busy = False
+        self._load_cover_batch(self.COVER_SCROLL_BATCH)
+
     def _on_cover_loaded(self, gen, row, image):
         if self._closing or gen != self._generation:
             return