Edit book: Add various validity checks for OPF files.

Check for incorrect idrefs, missing required sections, non-linear items
in the spine.

src/calibre/ebooks/oeb/polish/check/main.py

@@ -17,6 +17,7 @@ from calibre.ebooks.oeb.polish.check.parsing import (
 from calibre.ebooks.oeb.polish.check.images import check_raster_images
 from calibre.ebooks.oeb.polish.check.links import check_links, check_mimetypes
 from calibre.ebooks.oeb.polish.check.fonts import check_fonts
+from calibre.ebooks.oeb.polish.check.opf import check_opf
 
 XML_TYPES = frozenset(map(guess_type, ('a.xml', 'a.svg', 'a.opf', 'a.ncx')))
 
@@ -61,6 +62,7 @@ def run_checks(container):
     errors += check_fonts(container)
     errors += check_filenames(container)
     errors += check_ids(container)
+    errors += check_opf(container)
 
     return errors
 

src/calibre/ebooks/oeb/polish/check/opf.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env python
+# vim:fileencoding=utf-8
+from __future__ import (unicode_literals, division, absolute_import,
+                        print_function)
+
+__license__ = 'GPL v3'
+__copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
+
+from calibre import prepare_string_for_xml as xml
+from calibre.ebooks.oeb.polish.check.base import BaseError, WARN
+
+class MissingSection(BaseError):
+
+    def __init__(self, name, section_name):
+        BaseError.__init__(self, _('The <%s> section is missing from the OPF') % section_name, name)
+        self.HELP = xml(_(
+            'The <%s> section is required in the OPF file. You have to create one.') % section_name)
+
+class IncorrectIdref(BaseError):
+
+    def __init__(self, name, idref, lnum):
+        BaseError.__init__(self, _('idref="%s" points to unknown id') % idref, name, lnum)
+        self.HELP = xml(_(
+            'The idref="%s" points to an id that does not exist in the OPF') % idref)
+
+class NonLinearItems(BaseError):
+
+    level = WARN
+    has_multiple_locations = True
+
+    HELP = xml(_('There are items marked as non-linear in the <spine>.'
+                 ' These will be displayed in random order by different ebook readers.'
+                 ' Some will ignore the non-linear attribute, some will display'
+                 ' them at the end or the beginning of the book and some will'
+                 ' fail to display them at all. Instead of using non-linear items'
+                 ' simply place the items in the order you want them to be displayed.'))
+
+    INDIVIDUAL_FIX = _('Mark all non-linear items as linear')
+
+    def __init__(self, name, locs):
+        BaseError.__init__(self, _('Non-linear items in the spine'), name)
+        self.all_locations = [(name, x, None) for x in locs]
+
+    def __call__(self, container):
+        [elem.attrib.pop('linear') for elem in container.opf_xpath('//opf:spine/opf:itemref[@linear]')]
+        container.dirty(container.opf_name)
+        return True
+
+def check_opf(container):
+    errors = []
+
+    for tag in ('metadata', 'manifest', 'spine'):
+        if not container.opf_xpath('//opf:' + tag):
+            errors.append(MissingSection(container.opf_name, tag))
+
+    all_ids = set(container.opf_xpath('//*/@id'))
+    for elem in container.opf_xpath('//*[@idref]'):
+        if elem.get('idref') not in all_ids:
+            errors.append(IncorrectIdref(container.opf_name, elem.get('idref'), elem.sourceline))
+
+    nl_items = [elem.sourceline for elem in container.opf_xpath('//opf:spine/opf:itemref[@linear="no"]')]
+    if nl_items:
+        errors.append(NonLinearItems(container.opf_name, nl_items))
+
+    return errors