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Diffstat (limited to 'includes/libs/CSSJanus.php')
| -rw-r--r-- | includes/libs/CSSJanus.php | 323 |
1 files changed, 323 insertions, 0 deletions
diff --git a/includes/libs/CSSJanus.php b/includes/libs/CSSJanus.php new file mode 100644 index 00000000..aa04bc49 --- /dev/null +++ b/includes/libs/CSSJanus.php @@ -0,0 +1,323 @@ +<?php +/** + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * http://www.gnu.org/copyleft/gpl.html + * + */ + +/** + * This is a PHP port of CSSJanus, a utility that transforms CSS style sheets + * written for LTR to RTL. + * + * The original Python version of CSSJanus is Copyright 2008 by Google Inc. and + * is distributed under the Apache license. + * + * Original code: http://code.google.com/p/cssjanus/source/browse/trunk/cssjanus.py + * License of original code: http://code.google.com/p/cssjanus/source/browse/trunk/LICENSE + * @author Roan Kattouw + * + */ +class CSSJanus { + // Patterns defined as null are built dynamically by buildPatterns() + private static $patterns = array( + 'tmpToken' => '`TMP`', + 'nonAscii' => '[\200-\377]', + 'unicode' => '(?:(?:\\[0-9a-f]{1,6})(?:\r\n|\s)?)', + 'num' => '(?:[0-9]*\.[0-9]+|[0-9]+)', + 'unit' => '(?:em|ex|px|cm|mm|in|pt|pc|deg|rad|grad|ms|s|hz|khz|%)', + 'body_selector' => 'body\s*{\s*', + 'direction' => 'direction\s*:\s*', + 'escape' => null, + 'nmstart' => null, + 'nmchar' => null, + 'ident' => null, + 'quantity' => null, + 'possibly_negative_quantity' => null, + 'color' => null, + 'url_special_chars' => '[!#$%&*-~]', + 'valid_after_uri_chars' => '[\'\"]?\s*', + 'url_chars' => null, + 'lookahead_not_open_brace' => null, + 'lookahead_not_closing_paren' => null, + 'lookahead_for_closing_paren' => null, + 'lookbehind_not_letter' => '(?<![a-zA-Z])', + 'chars_within_selector' => '[^\}]*?', + 'noflip_annotation' => '\/\*\s*@noflip\s*\*\/', + 'noflip_single' => null, + 'noflip_class' => null, + 'comment' => '/\/\*[^*]*\*+([^\/*][^*]*\*+)*\//', + 'direction_ltr' => null, + 'direction_rtl' => null, + 'left' => null, + 'right' => null, + 'left_in_url' => null, + 'right_in_url' => null, + 'ltr_in_url' => null, + 'rtl_in_url' => null, + 'cursor_east' => null, + 'cursor_west' => null, + 'four_notation_quantity' => null, + 'four_notation_color' => null, + 'bg_horizontal_percentage' => null, + 'bg_horizontal_percentage_x' => null, + ); + + /** + * Build patterns we can't define above because they depend on other patterns. + */ + private static function buildPatterns() { + if ( !is_null( self::$patterns['escape'] ) ) { + // Patterns have already been built + return; + } + + $patterns =& self::$patterns; + $patterns['escape'] = "(?:{$patterns['unicode']}|\\[^\r\n\f0-9a-f])"; + $patterns['nmstart'] = "(?:[_a-z]|{$patterns['nonAscii']}|{$patterns['escape']})"; + $patterns['nmchar'] = "(?:[_a-z0-9-]|{$patterns['nonAscii']}|{$patterns['escape']})"; + $patterns['ident'] = "-?{$patterns['nmstart']}{$patterns['nmchar']}*"; + $patterns['quantity'] = "{$patterns['num']}(?:\s*{$patterns['unit']}|{$patterns['ident']})?"; + $patterns['possibly_negative_quantity'] = "((?:-?{$patterns['quantity']})|(?:inherit|auto))"; + $patterns['color'] = "(#?{$patterns['nmchar']}+)"; + $patterns['url_chars'] = "(?:{$patterns['url_special_chars']}|{$patterns['nonAscii']}|{$patterns['escape']})*"; + $patterns['lookahead_not_open_brace'] = "(?!({$patterns['nmchar']}|\r?\n|\s|#|\:|\.|\,|\+|>)*?{)"; + $patterns['lookahead_not_closing_paren'] = "(?!{$patterns['url_chars']}?{$patterns['valid_after_uri_chars']}\))"; + $patterns['lookahead_for_closing_paren'] = "(?={$patterns['url_chars']}?{$patterns['valid_after_uri_chars']}\))"; + $patterns['noflip_single'] = "/({$patterns['noflip_annotation']}{$patterns['lookahead_not_open_brace']}[^;}]+;?)/i"; + $patterns['noflip_class'] = "/({$patterns['noflip_annotation']}{$patterns['chars_within_selector']}})/i"; + $patterns['direction_ltr'] = "/({$patterns['direction']})ltr/i"; + $patterns['direction_rtl'] = "/({$patterns['direction']})rtl/i"; + $patterns['left'] = "/{$patterns['lookbehind_not_letter']}(left){$patterns['lookahead_not_closing_paren']}{$patterns['lookahead_not_open_brace']}/i"; + $patterns['right'] = "/{$patterns['lookbehind_not_letter']}(right){$patterns['lookahead_not_closing_paren']}{$patterns['lookahead_not_open_brace']}/i"; + $patterns['left_in_url'] = "/{$patterns['lookbehind_not_letter']}(left){$patterns['lookahead_for_closing_paren']}/i"; + $patterns['right_in_url'] = "/{$patterns['lookbehind_not_letter']}(right){$patterns['lookahead_for_closing_paren']}/i"; + $patterns['ltr_in_url'] = "/{$patterns['lookbehind_not_letter']}(ltr){$patterns['lookahead_for_closing_paren']}/i"; + $patterns['rtl_in_url'] = "/{$patterns['lookbehind_not_letter']}(rtl){$patterns['lookahead_for_closing_paren']}/i"; + $patterns['cursor_east'] = "/{$patterns['lookbehind_not_letter']}([ns]?)e-resize/"; + $patterns['cursor_west'] = "/{$patterns['lookbehind_not_letter']}([ns]?)w-resize/"; + $patterns['four_notation_quantity'] = "/{$patterns['possibly_negative_quantity']}(\s+){$patterns['possibly_negative_quantity']}(\s+){$patterns['possibly_negative_quantity']}(\s+){$patterns['possibly_negative_quantity']}/i"; + $patterns['four_notation_color'] = "/(-color\s*:\s*){$patterns['color']}(\s+){$patterns['color']}(\s+){$patterns['color']}(\s+){$patterns['color']}/i"; + // The two regexes below are parenthesized differently then in the original implementation to make the + // callback's job more straightforward + $patterns['bg_horizontal_percentage'] = "/(background(?:-position)?\s*:\s*[^%]*?)({$patterns['num']})(%\s*(?:{$patterns['quantity']}|{$patterns['ident']}))/"; + $patterns['bg_horizontal_percentage_x'] = "/(background-position-x\s*:\s*)({$patterns['num']})(%)/"; + } + + /** + * Transform an LTR stylesheet to RTL + * @param $css String: stylesheet to transform + * @param $swapLtrRtlInURL Boolean: If true, swap 'ltr' and 'rtl' in URLs + * @param $swapLeftRightInURL Boolean: If true, swap 'left' and 'right' in URLs + * @return Transformed stylesheet + */ + public static function transform( $css, $swapLtrRtlInURL = false, $swapLeftRightInURL = false ) { + // We wrap tokens in ` , not ~ like the original implementation does. + // This was done because ` is not a legal character in CSS and can only + // occur in URLs, where we escape it to %60 before inserting our tokens. + $css = str_replace( '`', '%60', $css ); + + self::buildPatterns(); + + // Tokenize single line rules with /* @noflip */ + $noFlipSingle = new CSSJanus_Tokenizer( self::$patterns['noflip_single'], '`NOFLIP_SINGLE`' ); + $css = $noFlipSingle->tokenize( $css ); + + // Tokenize class rules with /* @noflip */ + $noFlipClass = new CSSJanus_Tokenizer( self::$patterns['noflip_class'], '`NOFLIP_CLASS`' ); + $css = $noFlipClass->tokenize( $css ); + + // Tokenize comments + $comments = new CSSJanus_Tokenizer( self::$patterns['comment'], '`C`' ); + $css = $comments->tokenize( $css ); + + // LTR->RTL fixes start here + $css = self::fixDirection( $css ); + if ( $swapLtrRtlInURL ) { + $css = self::fixLtrRtlInURL( $css ); + } + + if ( $swapLeftRightInURL ) { + $css = self::fixLeftRightInURL( $css ); + } + $css = self::fixLeftAndRight( $css ); + $css = self::fixCursorProperties( $css ); + $css = self::fixFourPartNotation( $css ); + $css = self::fixBackgroundPosition( $css ); + + // Detokenize stuff we tokenized before + $css = $comments->detokenize( $css ); + $css = $noFlipClass->detokenize( $css ); + $css = $noFlipSingle->detokenize( $css ); + + return $css; + } + + /** + * Replace direction: ltr; with direction: rtl; and vice versa. + * + * The original implementation only does this inside body selectors + * and misses "body\n{\ndirection:ltr;\n}". This function does not have + * these problems. + * + * See http://code.google.com/p/cssjanus/issues/detail?id=15 and + * TODO: URL + */ + private static function fixDirection( $css ) { + $css = preg_replace( self::$patterns['direction_ltr'], + '$1' . self::$patterns['tmpToken'], $css ); + $css = preg_replace( self::$patterns['direction_rtl'], '$1ltr', $css ); + $css = str_replace( self::$patterns['tmpToken'], 'rtl', $css ); + + return $css; + } + + /** + * Replace 'ltr' with 'rtl' and vice versa in background URLs + */ + private static function fixLtrRtlInURL( $css ) { + $css = preg_replace( self::$patterns['ltr_in_url'], self::$patterns['tmpToken'], $css ); + $css = preg_replace( self::$patterns['rtl_in_url'], 'ltr', $css ); + $css = str_replace( self::$patterns['tmpToken'], 'rtl', $css ); + + return $css; + } + + /** + * Replace 'left' with 'right' and vice versa in background URLs + */ + private static function fixLeftRightInURL( $css ) { + $css = preg_replace( self::$patterns['left_in_url'], self::$patterns['tmpToken'], $css ); + $css = preg_replace( self::$patterns['right_in_url'], 'left', $css ); + $css = str_replace( self::$patterns['tmpToken'], 'right', $css ); + + return $css; + } + + /** + * Flip rules like left: , padding-right: , etc. + */ + private static function fixLeftAndRight( $css ) { + $css = preg_replace( self::$patterns['left'], self::$patterns['tmpToken'], $css ); + $css = preg_replace( self::$patterns['right'], 'left', $css ); + $css = str_replace( self::$patterns['tmpToken'], 'right', $css ); + + return $css; + } + + /** + * Flip East and West in rules like cursor: nw-resize; + */ + private static function fixCursorProperties( $css ) { + $css = preg_replace( self::$patterns['cursor_east'], + '$1' . self::$patterns['tmpToken'], $css ); + $css = preg_replace( self::$patterns['cursor_west'], '$1e-resize', $css ); + $css = str_replace( self::$patterns['tmpToken'], 'w-resize', $css ); + + return $css; + } + + /** + * Swap the second and fourth parts in four-part notation rules like + * padding: 1px 2px 3px 4px; + * + * Unlike the original implementation, this function doesn't suffer from + * the bug where whitespace is not preserved when flipping four-part rules + * and four-part color rules with multiple whitespace characters between + * colors are not recognized. + * See http://code.google.com/p/cssjanus/issues/detail?id=16 + */ + private static function fixFourPartNotation( $css ) { + $css = preg_replace( self::$patterns['four_notation_quantity'], '$1$2$7$4$5$6$3', $css ); + $css = preg_replace( self::$patterns['four_notation_color'], '$1$2$3$8$5$6$7$4', $css ); + + return $css; + } + + /** + * Flip horizontal background percentages. + */ + private static function fixBackgroundPosition( $css ) { + $css = preg_replace_callback( self::$patterns['bg_horizontal_percentage'], + array( 'self', 'calculateNewBackgroundPosition' ), $css ); + $css = preg_replace_callback( self::$patterns['bg_horizontal_percentage_x'], + array( 'self', 'calculateNewBackgroundPosition' ), $css ); + + return $css; + } + + /** + * Callback for calculateNewBackgroundPosition() + */ + private static function calculateNewBackgroundPosition( $matches ) { + return $matches[1] . ( 100 - $matches[2] ) . $matches[3]; + } +} + +/** + * Utility class used by CSSJanus that tokenizes and untokenizes things we want + * to protect from being janused. + * @author Roan Kattouw + */ +class CSSJanus_Tokenizer { + private $regex, $token; + private $originals; + + /** + * Constructor + * @param $regex string Regular expression whose matches to replace by a token. + * @param $token string Token + */ + public function __construct( $regex, $token ) { + $this->regex = $regex; + $this->token = $token; + $this->originals = array(); + } + + /** + * Replace all occurrences of $regex in $str with a token and remember + * the original strings. + * @param $str String to tokenize + * @return string Tokenized string + */ + public function tokenize( $str ) { + return preg_replace_callback( $this->regex, array( $this, 'tokenizeCallback' ), $str ); + } + + private function tokenizeCallback( $matches ) { + $this->originals[] = $matches[0]; + return $this->token; + } + + /** + * Replace tokens with their originals. If multiple strings were tokenized, it's important they be + * detokenized in exactly the SAME ORDER. + * @param $str String: previously run through tokenize() + * @return string Original string + */ + public function detokenize( $str ) { + // PHP has no function to replace only the first occurrence or to + // replace occurrences of the same string with different values, + // so we use preg_replace_callback() even though we don't really need a regex + return preg_replace_callback( '/' . preg_quote( $this->token, '/' ) . '/', + array( $this, 'detokenizeCallback' ), $str ); + } + + private function detokenizeCallback( $matches ) { + $retval = current( $this->originals ); + next( $this->originals ); + + return $retval; + } +} |