Fix open files with PDF metadata reader

src/calibre/ebooks/metadata/meta.py

@@ -39,13 +39,13 @@ def metadata_from_formats(formats):
             return mi2
     
     for path, ext in zip(formats, extensions):
-        stream = open(path, 'rb')
-        try:
-            mi.smart_update(get_metadata(stream, stream_type=ext, use_libprs_metadata=True))
-        except:
-            continue
-        if getattr(mi, 'application_id', None) is not None:
-            return mi
+        with open(path, 'rb') as stream:
+            try:
+                mi.smart_update(get_metadata(stream, stream_type=ext, use_libprs_metadata=True))
+            except:
+                continue
+            if getattr(mi, 'application_id', None) is not None:
+                return mi
     
     if not mi.title:
         mi.title = _('Unknown')

src/calibre/ebooks/metadata/pdf.py

@@ -67,6 +67,8 @@ def set_metadata(stream, mi):
     stream.seek(0)
 
 def get_cover(stream):
+    data = StringIO.StringIO()
+    
     try:
         pdf = PdfFileReader(stream)
         output = PdfFileWriter()
@@ -88,12 +90,12 @@ def get_cover(stream):
             
             img = Image.open('%s.jpg' % cover_path)
             
-            data = StringIO.StringIO()
             img.save(data, 'JPEG')
-            return data.getvalue()
     except:
         import traceback
         traceback.print_exc()
+        
+    return data.getvalue()
 
 def option_parser():
     p = get_parser('pdf')