From e126ddc5180f07fc30e320cdbddc704a99c028d4 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Wed, 8 Dec 2010 10:09:52 -0700
Subject: [PATCH] Fix bug in cover cache that could cause it to keep a large
 number of covers in memory. Showed up when adding large numbers of books to
 calibre. Fixes #7813 (errors found in terminal after latest stable Calibre
 closed)

---
 src/calibre/library/caches.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/calibre/library/caches.py b/src/calibre/library/caches.py
index 5b6b79e3df..e19dd8c1ae 100644
--- a/src/calibre/library/caches.py
+++ b/src/calibre/library/caches.py
@@ -129,6 +129,7 @@ class CoverCache(Thread): # {{{
         self.keep_running = True
         self.cache = {}
         self.lock = RLock()
+        self.allowed_ids = frozenset([])
         self.null_image = QImage()
 
     def stop(self):
@@ -175,6 +176,9 @@ class CoverCache(Thread): # {{{
                 break
             for id_ in ids:
                 time.sleep(0.050) # Limit 20/second to not overwhelm the GUI
+                with self.lock:
+                    if id_ not in self.allowed_ids:
+                        continue
                 try:
                     img = self._image_for_id(id_)
                 except:
@@ -193,6 +197,7 @@ class CoverCache(Thread): # {{{
 
     def set_cache(self, ids):
         with self.lock:
+            self.allowed_ids = frozenset(ids)
             already_loaded = set([])
             for id in self.cache.keys():
                 if id in ids: