When reading the cover from comic files, ignore any image files inside __MACOSX/ directories. Fixes #1539414 [Calibre can't extract cbz/cbr cover with __macosx folder](https://bugs.launchpad.net/calibre/+bug/1539414)

src/calibre/customize/builtins.py

@@ -3,7 +3,7 @@
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, glob, functools, re
+import os, glob, re
 from calibre import guess_type
 from calibre.customize import (FileTypePlugin, MetadataReaderPlugin,
     MetadataWriterPlugin, PreferencesPlugin, InterfaceActionBase, StoreBase)
@@ -143,14 +143,11 @@ class ComicMetadataReader(MetadataReaderPlugin):
             elif id_.startswith(b'PK'):
                 ftype = 'cbz'
         if ftype == 'cbr':
-            from calibre.utils.unrar import extract_first_alphabetically as extract_first
-            extract_first
+            from calibre.utils.unrar import extract_cover_image
         else:
-            from calibre.libunzip import extract_member
-            extract_first = functools.partial(extract_member,
-                    sort_alphabetically=True)
+            from calibre.libunzip import extract_cover_image
         from calibre.ebooks.metadata import MetaInformation
-        ret = extract_first(stream)
+        ret = extract_cover_image(stream)
         mi = MetaInformation(None, None)
         stream.seek(0)
         if ftype in {'cbr', 'cbz'}:

src/calibre/libunzip.py

@@ -58,3 +58,14 @@ def extract_member(filename, match=re.compile(r'\.(jpg|jpeg|gif|png)\s*$', re.I)
     for name in names:
         if match.search(name):
             return name, zf.read(name)
+
+comic_exts = {'png', 'jpg', 'jpeg', 'gif', 'webp'}
+
+def name_ok(name):
+    return bool(name and not name.startswith('__MACOSX/') and name.rpartition('.')[-1].lower() in comic_exts)
+
+def extract_cover_image(filename):
+    with zipfile.ZipFile(filename) as zf:
+        for name in sorted(zf.namelist(), key=sort_key):
+            if name_ok(name):
+                return name, zf.read(name)

src/calibre/utils/unrar.py

@@ -190,6 +190,12 @@ def extract_first_alphabetically(stream):
             {'png', 'jpg', 'jpeg', 'gif', 'webp'}], key=sort_key)
     return extract_member(stream, name=names_[0], match=None)
 
+def extract_cover_image(stream):
+    from calibre.libunzip import sort_key, name_ok
+    for name in sorted(names(stream), key=sort_key):
+        if name_ok(name):
+            return extract_member(stream, name=name, match=None)
+
 # Test normal RAR file {{{
 def test_basic():