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