From 33a1617f8997aa129a31234502ea47642fa79e38 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Sat, 10 Mar 2012 14:57:42 +0530
Subject: [PATCH] Conversion pipeline: Fix @import rules in CSS stylesheets
 that have comments on their first few lines being ignored. Also use cssutils
 to process @import rules instead of doing it ourselves.

---
 src/calibre/ebooks/conversion/preprocess.py |  9 +++++-
 src/calibre/ebooks/oeb/base.py              | 32 +++------------------
 2 files changed, 12 insertions(+), 29 deletions(-)

diff --git a/src/calibre/ebooks/conversion/preprocess.py b/src/calibre/ebooks/conversion/preprocess.py
index dc10a60f2f..617de18555 100644
--- a/src/calibre/ebooks/conversion/preprocess.py
+++ b/src/calibre/ebooks/conversion/preprocess.py
@@ -289,10 +289,17 @@ class CSSPreProcessor(object):
         data = self.MS_PAT.sub(self.ms_sub, data)
         if not add_namespace:
             return data
+
+        # Remove comments as the following namespace logic will break if there
+        # are commented lines before the first @import or @charset rule. Since
+        # the conversion will remove all stylesheets anyway, we don't lose
+        # anything
+        data = re.sub(ur'/\*.*?\*/', u'', data, flags=re.DOTALL)
+
         ans, namespaced = [], False
         for line in data.splitlines():
             ll = line.lstrip()
-            if not (namespaced or ll.startswith('@import') or
+            if not (namespaced or ll.startswith('@import') or not ll or
                         ll.startswith('@charset')):
                 ans.append(XHTML_CSS_NAMESPACE.strip())
                 namespaced = True
diff --git a/src/calibre/ebooks/oeb/base.py b/src/calibre/ebooks/oeb/base.py
index a9608105f9..450d50fd40 100644
--- a/src/calibre/ebooks/oeb/base.py
+++ b/src/calibre/ebooks/oeb/base.py
@@ -832,22 +832,8 @@ class Manifest(object):
 
 
         def _parse_css(self, data):
-            from cssutils.css import CSSRule
-            from cssutils import CSSParser, log
+            from cssutils import CSSParser, log, resolveImports
             log.setLevel(logging.WARN)
-            def get_style_rules_from_import(import_rule):
-                ans = []
-                if not import_rule.styleSheet:
-                    return ans
-                rules = import_rule.styleSheet.cssRules
-                for rule in rules:
-                    if rule.type == CSSRule.IMPORT_RULE:
-                        ans.extend(get_style_rules_from_import(rule))
-                    elif rule.type in (CSSRule.FONT_FACE_RULE,
-                            CSSRule.STYLE_RULE):
-                        ans.append(rule)
-                return ans
-
             self.oeb.log.debug('Parsing', self.href, '...')
             data = self.oeb.decode(data)
             data = self.oeb.css_preprocessor(data, add_namespace=True)
@@ -855,19 +841,8 @@ class Manifest(object):
                                fetcher=self.override_css_fetch or self._fetch_css,
                                log=_css_logger)
             data = parser.parseString(data, href=self.href)
+            data = resolveImports(data)
             data.namespaces['h'] = XHTML_NS
-            import_rules = list(data.cssRules.rulesOfType(CSSRule.IMPORT_RULE))
-            rules_to_append = []
-            insert_index = None
-            for r in data.cssRules.rulesOfType(CSSRule.STYLE_RULE):
-                insert_index = data.cssRules.index(r)
-                break
-            for rule in import_rules:
-                rules_to_append.extend(get_style_rules_from_import(rule))
-            for r in reversed(rules_to_append):
-                data.insertRule(r, index=insert_index)
-            for rule in import_rules:
-                data.deleteRule(rule)
             return data
 
         def _fetch_css(self, path):
@@ -880,7 +855,8 @@ class Manifest(object):
                 self.oeb.logger.warn('CSS import of non-CSS file %r' % path)
                 return (None, None)
             data = item.data.cssText
-            return ('utf-8', data)
+            enc = None if isinstance(data, unicode) else 'utf-8'
+            return (enc, data)
 
         # }}}