Fix #2907 (Calibre throws an error when trying to convert a free ebook that comes with BN eReader.)

src/calibre/__init__.py

@@ -384,6 +384,15 @@ def entity_to_unicode(match, exceptions=[], encoding='cp1252'):
     except KeyError:
         return '&'+ent+';'
 
+_ent_pat = re.compile(r'&(\S+);')
+
+def prepare_string_for_xml(raw, attribute=False):
+    raw = _ent_pat.sub(entity_to_unicode, raw)
+    raw = raw.replace('&', '&amp;').replace('<', '&lt;').replace('>', '&gt;')
+    if attribute:
+        raw = raw.replace('"', '&quot;').replace("'", '&apos;')
+    return raw
+
 if isosx:
     fdir = os.path.expanduser('~/.fonts')
     try:

src/calibre/ebooks/epub/output.py

@@ -12,7 +12,7 @@
 from calibre.customize.conversion import OutputFormatPlugin
 from calibre.ptempfile import TemporaryDirectory
 from calibre.constants import __appname__, __version__
-from calibre import strftime, guess_type
+from calibre import strftime, guess_type, prepare_string_for_xml
 from calibre.customize.conversion import OptionRecommendation
 
 from lxml import etree
@@ -210,6 +210,7 @@ def default_cover(self):
         id, href = self.oeb.manifest.generate('calibre-logo',
                 'calibre-logo.png')
         self.oeb.manifest.add(id, href, 'image/png', data=img_data)
+        title, author = map(prepare_string_for_xml, (title, author))
         html = self.TITLEPAGE%dict(title=title, author=author,
                 date=strftime('%d %b, %Y'),
                 app=__appname__ +' '+__version__,