CSSJanus: Support text-shadow and box-shadow flipping

We just need to negate the horizontal offset value in both of them.

This only supports *a single shadow* per element; multiple shadows
are not supported (only the first will be flipped).

Second attempt. First, reverted one: I14822955.

Bug: 45677
Change-Id: I97ee7431e1a5acb35d594076a88a0f9acf290402

diff --git a/includes/libs/CSSJanus.php b/includes/libs/CSSJanus.php
index f70e00a..259c9ff 100644 (file)
--- a/includes/libs/CSSJanus.php
+++ b/includes/libs/CSSJanus.php
@@ -77,6 +77,9 @@ class CSSJanus {
                'four_notation_quantity' => null,
                'four_notation_color' => null,
                'border_radius' => null,
+               'box_shadow' => null,
+               'text_shadow1' => null,
+               'text_shadow2' => null,
                'bg_horizontal_percentage' => null,
                'bg_horizontal_percentage_x' => null,
        );
@@ -117,6 +120,9 @@ class CSSJanus {
                $patterns['four_notation_quantity'] = "/(:\s*){$patterns['possibly_negative_quantity']}(\s+){$patterns['possibly_negative_quantity']}(\s+){$patterns['possibly_negative_quantity']}(\s+){$patterns['possibly_negative_quantity']}(\s*[;}])/i";
                $patterns['four_notation_color'] = "/(-color\s*:\s*){$patterns['color']}(\s+){$patterns['color']}(\s+){$patterns['color']}(\s+){$patterns['color']}(\s*[;}])/i";
                $patterns['border_radius'] = "/(border-radius\s*:\s*){$patterns['possibly_negative_quantity']}(\s+){$patterns['possibly_negative_quantity']}(\s+){$patterns['possibly_negative_quantity']}(\s+){$patterns['possibly_negative_quantity']}(\s*[;}])/i";
+               $patterns['box_shadow'] = "/(box-shadow\s*:\s*(?:inset\s*)?){$patterns['possibly_negative_quantity']}/i";
+               $patterns['text_shadow1'] = "/(text-shadow\s*:\s*){$patterns['color']}(\s*){$patterns['possibly_negative_quantity']}/i";
+               $patterns['text_shadow2'] = "/(text-shadow\s*:\s*){$patterns['possibly_negative_quantity']}/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']}))/";
@@ -164,6 +170,7 @@ class CSSJanus {
                $css = self::fixFourPartNotation( $css );
                $css = self::fixBorderRadius( $css );
                $css = self::fixBackgroundPosition( $css );
+               $css = self::fixShadows( $css );
 
                // Detokenize stuff we tokenized before
                $css = $comments->detokenize( $css );
@@ -262,7 +269,6 @@ class CSSJanus {
        private static function fixFourPartNotation( $css ) {
                $css = preg_replace( self::$patterns['four_notation_quantity'], '$1$2$3$8$5$6$7$4$9', $css );
                $css = preg_replace( self::$patterns['four_notation_color'], '$1$2$3$8$5$6$7$4$9', $css );
-
                return $css;
        }
 
@@ -282,6 +288,41 @@ class CSSJanus {
                return $css;
        }
 
+       /**
+        * Negates horizontal offset in box-shadow and text-shadow rules.
+        *
+        * @param $css string
+        * @return string
+        */
+       private static function fixShadows( $css ) {
+               // Flips the sign of a CSS value, possibly with a unit.
+               // (We can't just negate the value with unary minus due to the units.)
+               $flipSign = function ( $cssValue ) {
+                       // Don't mangle zeroes
+                       if ( intval( $cssValue ) === 0 ) {
+                               return $cssValue;
+                       } elseif ( $cssValue[0] === '-' ) {
+                               return substr( $cssValue, 1 );
+                       } else {
+                               return "-" . $cssValue;
+                       }
+               };
+
+               $css = preg_replace_callback( self::$patterns['box_shadow'], function ( $matches ) use ( $flipSign ) {
+                       return $matches[1] . $flipSign( $matches[2] );
+               }, $css );
+
+               $css = preg_replace_callback( self::$patterns['text_shadow1'], function ( $matches ) use ( $flipSign ) {
+                       return $matches[1] . $matches[2] . $matches[3] . $flipSign( $matches[4] );
+               }, $css );
+
+               $css = preg_replace_callback( self::$patterns['text_shadow2'], function ( $matches ) use ( $flipSign ) {
+                       return $matches[1] . $flipSign( $matches[2] );
+               }, $css );
+
+               return $css;
+       }
+
        /**
         * Flip horizontal background percentages.
         * @param $css string

diff --git a/tests/phpunit/includes/libs/CSSJanusTest.php b/tests/phpunit/includes/libs/CSSJanusTest.php
index b51dbdf..6d15830 100644 (file)
--- a/tests/phpunit/includes/libs/CSSJanusTest.php
+++ b/tests/phpunit/includes/libs/CSSJanusTest.php
@@ -196,6 +196,28 @@ class CSSJanusTest extends MediaWikiTestCase {
                                '.foo { padding: 1px; }'
                        ),
 
+                       // text-shadow and box-shadow
+                       array(
+                               '.foo { box-shadow: -6px 3px 8px 5px rgba(0, 0, 0, 0.25); }',
+                               '.foo { box-shadow: 6px 3px 8px 5px rgba(0, 0, 0, 0.25); }',
+                       ),
+                       array(
+                               '.foo { box-shadow: inset -6px 3px 8px 5px rgba(0, 0, 0, 0.25); }',
+                               '.foo { box-shadow: inset 6px 3px 8px 5px rgba(0, 0, 0, 0.25); }',
+                       ),
+                       array(
+                               '.foo { text-shadow: orange 2px 0; }',
+                               '.foo { text-shadow: orange -2px 0; }',
+                       ),
+                       array(
+                               '.foo { text-shadow: 2px 0 orange; }',
+                               '.foo { text-shadow: -2px 0 orange; }',
+                       ),
+                       array(
+                               // Don't mangle zeroes
+                               '.foo { text-shadow: orange 0 2px; }'
+                       ),
+
                        // Direction
                        // Note: This differs from the Python implementation,
                        // see also CSSJanus::fixDirection for more info.