Add a check for aliased fonts

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

@@ -0,0 +1,127 @@
+#!/usr/bin/env python
+# vim:fileencoding=utf-8
+from __future__ import (unicode_literals, division, absolute_import,
+                        print_function)
+
+__license__ = 'GPL v3'
+__copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
+
+from cssutils.css import CSSRule
+
+from calibre import force_unicode
+from calibre.constants import plugins
+from calibre.ebooks.oeb.base import OEB_DOCS, OEB_STYLES
+from calibre.ebooks.oeb.polish.check.base import BaseError, WARN
+from calibre.ebooks.oeb.polish.container import guess_type, OEB_FONTS
+from calibre.ebooks.oeb.polish.pretty import pretty_script_or_style
+from calibre.utils.fonts.utils import get_all_font_names
+
+woff = plugins['woff'][0]
+
+class InvalidFont(BaseError):
+
+    HELP = _('This font could not be processed. It most likely will'
+             ' not work in an ebook reader, either')
+
+def fix_declaration(style, css_name, font_name):
+    ff = style.getPropertyCSSValue('font-family')
+    changed = False
+    if ff is not None:
+        for i in xrange(ff.length):
+            val = ff.item(i)
+            if val.value and val.value.lower() == css_name.lower():
+                val.value = font_name
+                changed = True
+    return changed
+
+def fix_sheet(sheet, css_name, font_name):
+    changed = False
+    for rule in sheet.cssRules:
+        if rule.type in (CSSRule.FONT_FACE_RULE, CSSRule.STYLE_RULE):
+            if fix_declaration(rule.style, css_name, font_name):
+                changed = True
+    return changed
+
+class FontAliasing(BaseError):
+
+    level = WARN
+
+    def __init__(self, font_name, css_name, name, line):
+        BaseError.__init__(self, _('The CSS font-family name %s does not match the actual font name %s') % (css_name, font_name), name, line)
+        self.HELP = _('The font family name specified in the CSS @font-face rule: "{0}" does'
+                      ' not match the font name inside the actual font file: "{1}". This can'
+                      ' cause problems in some viewers. You should change the CSS font name'
+                      ' to match the actual font name.').format(css_name, font_name)
+        self.INDIVIDUAL_FIX = _('Change the font name {0} to {1} everywhere').format(css_name, font_name)
+        self.font_name, self.css_name = font_name, css_name
+
+    def __call__(self, container):
+        changed = False
+        for name, mt in container.mime_map.iteritems():
+            if mt in OEB_STYLES:
+                sheet = container.parsed(name)
+                if fix_sheet(sheet, self.css_name, self.font_name):
+                    container.dirty(name)
+                    changed = True
+            elif mt in OEB_DOCS:
+                for style in container.parsed(name).xpath('//*[local-name()="style"]'):
+                    if style.get('type', 'text/css') == 'text/css':
+                        sheet = container.parse_css(style.text)
+                        if fix_sheet(sheet, self.css_name, self.font_name):
+                            style.text = force_unicode(sheet.cssText, 'utf-8')
+                            pretty_script_or_style(container, style)
+                            container.dirty(name)
+                            changed = True
+                for elem in container.parsed(name).xpath('//*[@style and contains(@style, "font-family")]'):
+                    style = container.parse_css(elem.get('style'), is_declaration=True)
+                    if fix_declaration(style, self.css_name, self.font_name):
+                        elem.set('style', force_unicode(style.cssText, 'utf-8').replace('\n', ' '))
+                        container.dirty(name)
+                        changed = True
+        return changed
+
+def check_fonts(container):
+    font_map = {}
+    errors = []
+    for name, mt in container.mime_map.iteritems():
+        if mt in OEB_FONTS:
+            raw = container.raw_data(name)
+            if mt == guess_type('a.woff'):
+                try:
+                    raw = woff.from_woff(raw)
+                except Exception as e:
+                    errors.append(InvalidFont(_('Not a valid WOFF font: %s') % e, name))
+                    continue
+            try:
+                name_map = get_all_font_names(raw)
+            except Exception as e:
+                errors.append(InvalidFont(_('Not a valid font: %s') % e, name))
+                continue
+            font_map[name] = name_map.get('family_name', None) or name_map.get('preferred_family_name', None) or name_map.get('wws_family_name', None)
+
+    sheets = []
+    for name, mt in container.mime_map.iteritems():
+        if mt in OEB_STYLES:
+            sheets.append((name, container.parsed(name), None))
+        elif mt in OEB_DOCS:
+            for style in container.parsed(name).xpath('//*[local-name()="style"]'):
+                if style.get('type', 'text/css') == 'text/css':
+                    sheets.append((name, container.parse_css(style.text), style.sourceline))
+
+    for name, sheet, line_offset in sheets:
+        for rule in sheet.cssRules.rulesOfType(CSSRule.FONT_FACE_RULE):
+            src = rule.style.getPropertyCSSValue('src')
+            if src is not None and src.length > 0:
+                href = getattr(src.item(0), 'uri', None)
+                if href is not None:
+                    fname = container.href_to_name(href, name)
+                    font_name = font_map.get(fname, None)
+                    if font_name is None:
+                        continue
+                    ff = rule.style.getPropertyCSSValue('font-family')
+                    if ff is not None and ff.length > 0:
+                        ff = getattr(ff.item(0), 'value', None)
+                        if ff is not None and ff != font_name:
+                            errors.append(FontAliasing(font_name, ff, name, line_offset))
+
+    return errors

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

@@ -15,6 +15,7 @@ from calibre.ebooks.oeb.polish.check.base import run_checkers
 from calibre.ebooks.oeb.polish.check.parsing import check_xml_parsing, check_css_parsing, fix_style_tag
 from calibre.ebooks.oeb.polish.check.images import check_raster_images
 from calibre.ebooks.oeb.polish.check.links import check_links
+from calibre.ebooks.oeb.polish.check.fonts import check_fonts
 
 XML_TYPES = frozenset(map(guess_type, ('a.xml', 'a.svg', 'a.opf', 'a.ncx')))
 
@@ -50,6 +51,7 @@ def run_checks(container):
                 errors.extend(check_css_parsing(name, style.text, line_offset=style.sourceline - 1))
 
     errors += check_links(container)
+    errors += check_fonts(container)
 
     return errors
 

src/calibre/ebooks/oeb/polish/container.py

@@ -430,7 +430,7 @@ class Container(object):  # {{{
             ans = self.decode(ans)
         return ans
 
-    def parse_css(self, data, fname='<string>'):
+    def parse_css(self, data, fname='<string>', is_declaration=False):
         from cssutils import CSSParser, log
         log.setLevel(logging.WARN)
         log.raiseExceptions = False
@@ -441,6 +441,9 @@ class Container(object):  # {{{
         parser = CSSParser(loglevel=logging.WARNING,
                            # We dont care about @import rules
                            fetcher=lambda x: (None, None), log=_css_logger)
+        if is_declaration:
+            data = parser.parseStyle(data, validate=False)
+        else:
             data = parser.parseString(data, href=fname, validate=False)
         return data