Use the new font parsing code for normalize_css

src/tinycss/fonts3.py

@@ -7,6 +7,8 @@ __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 
+import re
+from future_builtins import map
 from tinycss.css21 import CSS21Parser, ParseError
 from .tokenizer import tokenize_grouped
 
@@ -38,6 +40,18 @@ def parse_font_family_tokens(tokens):
 def parse_font_family(css_string):
     return parse_font_family_tokens(tokenize_grouped(type('')(css_string).strip()))
 
+def serialize_font_family(families):
+    def one(x):
+        xl = x.lower()
+        if xl in GENERIC_FAMILIES:
+            if xl == 'sansserif':
+                xl = 'sans-serif'
+            return xl
+        if SIMPLE_NAME_PAT.match(x) is not None:
+            return x
+        return '"%s"' % x.replace('"', r'\"')
+    return ', '.join(map(one, families))
+
 GLOBAL_IDENTS = frozenset('inherit initial unset normal'.split())
 STYLE_IDENTS = frozenset('italic oblique'.split())
 VARIANT_IDENTS = frozenset(('small-caps',))
@@ -47,6 +61,8 @@ BEFORE_SIZE_IDENTS = STYLE_IDENTS | VARIANT_IDENTS | WEIGHT_IDENTS | STRETCH_IDE
 SIZE_IDENTS = frozenset('xx-small x-small small medium large x-large xx-large larger smaller'.split())
 WEIGHT_SIZES = frozenset(map(int, '100 200 300 400 500 600 700 800 900'.split()))
 LEGACY_FONT_SPEC = frozenset('caption icon menu message-box small-caption status-bar'.split())
+GENERIC_FAMILIES = frozenset('serif sans-serif sansserif cursive fantasy monospace'.split())
+SIMPLE_NAME_PAT = re.compile(r'[a-zA-Z][a-zA-Z0-9_-]*$')
 
 def parse_font(css_string):
     # See https://www.w3.org/TR/css-fonts-3/#font-prop