+<?php
+/**
+ * PHP-provided functions for LESS; see docs for $wgResourceLoaderLESSFunctions
+ *
+ * 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
+ *
+ * @file
+ */
+
+class ResourceLoaderLESSFunctions {
+ /**
+ * Check if an image file reference is suitable for embedding.
+ * An image is embeddable if it (a) exists, (b) has a suitable MIME-type,
+ * (c) does not exceed IE<9 size limit of 32kb. This is a LESS predicate
+ * function; it returns a LESS boolean value and can thus be used as a
+ * mixin guard.
+ *
+ * @par Example:
+ * @code
+ * .background-image(@url) when(embeddable(@url)) {
+ * background-image: url(@url) !ie;
+ * }
+ * @endcode
+ */
+ public static function embeddable( $frame, $less ) {
+ $base = pathinfo( $less->parser->sourceName, PATHINFO_DIRNAME );
+ $url = $frame[2][0];
+ $file = realpath( $base . '/' . $url );
+ $embeddable = ( $file
+ && strpos( $url, '//' ) === false
+ && filesize( $file ) < CSSMin::EMBED_SIZE_LIMIT
+ && CSSMin::getMimeType( $file ) !== false ) ? 'true' : 'false';
+ return array( 'keyword', $embeddable );
+ }
+
+ /**
+ * Convert an image URI to a base64-encoded data URI.
+ *
+ * @par Example:
+ * @code
+ * .fancy-button {
+ * background-image: embed('../images/button-bg.png');
+ * }
+ * @endcode
+ */
+ public static function embed( $frame, $less ) {
+ $base = pathinfo( $less->parser->sourceName, PATHINFO_DIRNAME );
+ $url = $frame[2][0];
+ $file = realpath( $base . '/' . $url );
+
+ $data = CSSMin::encodeImageAsDataURI( $file );
+ $less->embeddedFiles[ $file ] = filemtime( $file );
+ return 'url(' . $data . ')';
+ }
+}