From 614e30402994243374415a4ec4b7de6e0355d14f Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Wed, 6 Jul 2016 10:47:34 +0530
Subject: [PATCH] A spot of minor refactoring

---
 src/calibre/ebooks/metadata/opf2.py | 16 ++++++++++------
 src/calibre/ebooks/metadata/opf3.py |  4 +++-
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/src/calibre/ebooks/metadata/opf2.py b/src/calibre/ebooks/metadata/opf2.py
index 2ee4d556e7..3d8be41064 100644
--- a/src/calibre/ebooks/metadata/opf2.py
+++ b/src/calibre/ebooks/metadata/opf2.py
@@ -1152,6 +1152,15 @@ class OPF(object):  # {{{
                         if os.access(os.path.join(self.base_dir, prefix+suffix), os.R_OK):
                             return cpath
 
+    @property
+    def epub3_raster_cover(self):
+        for item in self.itermanifest():
+            props = set((item.get('properties') or '').lower().split())
+            if 'cover-image' in props:
+                mt = item.get('media-type', '')
+                if mt and 'xml' not in mt and 'html' not in mt:
+                    return item.get('href', None)
+
     @property
     def raster_cover(self):
         covers = self.raster_cover_path(self.metadata)
@@ -1168,12 +1177,7 @@ class OPF(object):  # {{{
                     if mt and 'xml' not in mt and 'html' not in mt:
                         return item.get('href', None)
         elif self.package_version >= 3.0:
-            for item in self.itermanifest():
-                props = set((item.get('properties') or '').lower().split())
-                if 'cover-image' in props:
-                    mt = item.get('media-type', '')
-                    if mt and 'xml' not in mt and 'html' not in mt:
-                        return item.get('href', None)
+            return self.epub3_raster_cover
 
     @property
     def guide_raster_cover(self):
diff --git a/src/calibre/ebooks/metadata/opf3.py b/src/calibre/ebooks/metadata/opf3.py
index 82b8ad3e54..7bfd51becc 100644
--- a/src/calibre/ebooks/metadata/opf3.py
+++ b/src/calibre/ebooks/metadata/opf3.py
@@ -116,7 +116,9 @@ def simple_text(f):
         return normalize_whitespace(f(*args, **kw))
     return wrapper
 
-def items_with_property(root, q, prefixes):
+def items_with_property(root, q, prefixes=None):
+    if prefixes is None:
+        prefixes = read_prefixes(root)
     q = expand_prefix(q, known_prefixes).lower()
     for item in XPath("./opf:manifest/opf:item[@properties]")(root):
         for prop in (item.get('properties') or '').lower().split():