Fix bug with polygon point parsing. Fix bug 368716: tiny CSS parser to find referenced elements in style element

yocto_css.py

@@ -0,0 +1,72 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+#  yocto-css, an extremely bare minimum CSS parser
+#
+#  Copyright 2009 Jeff Schiller
+#
+#  This file is part of Scour, http://www.codedread.com/scour/
+#
+#   Licensed under the Apache License, Version 2.0 (the "License");
+#   you may not use this file except in compliance with the License.
+#   You may obtain a copy of the License at
+#
+#       http://www.apache.org/licenses/LICENSE-2.0
+#
+#   Unless required by applicable law or agreed to in writing, software
+#   distributed under the License is distributed on an "AS IS" BASIS,
+#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#   See the License for the specific language governing permissions and
+#   limitations under the License.
+
+# In order to resolve Bug 368716 (https://bugs.launchpad.net/scour/+bug/368716)
+# scour needed a bare-minimum CSS parser in order to determine if some elements
+# were still referenced by CSS properties.
+
+# I looked at css-py (a CSS parser built in Python), but that library 
+# is about 35k of Python and requires ply to be installed.  I just need 
+# something very basic to suit scour's needs.
+
+# yocto-css takes a string of CSS and tries to spit out a list of rules
+# A rule is an associative array (dictionary) with the following keys:
+# - selector: contains the string of the selector (see CSS grammar)
+# - properties: contains an associative array of CSS properties for this rule
+
+# TODO: need to build up some unit tests for yocto_css
+
+# stylesheet  : [ CDO | CDC | S | statement ]*;
+# statement   : ruleset | at-rule;
+# at-rule     : ATKEYWORD S* any* [ block | ';' S* ];
+# block       : '{' S* [ any | block | ATKEYWORD S* | ';' S* ]* '}' S*;
+# ruleset     : selector? '{' S* declaration? [ ';' S* declaration? ]* '}' S*;
+# selector    : any+;
+# declaration : property S* ':' S* value;
+# property    : IDENT;
+# value       : [ any | block | ATKEYWORD S* ]+;
+# any         : [ IDENT | NUMBER | PERCENTAGE | DIMENSION | STRING
+#               | DELIM | URI | HASH | UNICODE-RANGE | INCLUDES
+#               | DASHMATCH | FUNCTION S* any* ')' 
+#               | '(' S* any* ')' | '[' S* any* ']' ] S*;
+
+def parseCssString(str):
+	rules = []
+	# first, split on } to get the rule chunks
+	chunks = str.split('}')
+	for chunk in chunks:
+		# second, split on { to get the selector and the list of properties
+		bits = chunk.split('{')
+		if len(bits) != 2: continue
+		rule = {}
+		rule['selector'] = bits[0].strip()
+		# third, split on ; to get the property declarations
+		bites = bits[1].strip().split(';')
+		if len(bites) < 1: continue
+		props = {}
+		for bite in bites:
+			# fourth, split on : to get the property name and value
+			nibbles = bite.strip().split(':')
+			if len(nibbles) != 2: continue
+			props[nibbles[0].strip()] = nibbles[1].strip()
+		rule['properties'] = props
+		rules.append(rule)
+	return rules