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+<?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;
+ }
+}