CSSMin.php

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<?php
class CSSMin {

    /* Constants */

    const EMBED_SIZE_LIMIT = 24576;
    const URL_REGEX = 'url\(\s*[\'"]?(?P<file>[^\?\)\'"]*)(?P<query>\??[^\)\'"]*)[\'"]?\s*\)';

    /* Protected Static Members */

    protected static $mimeTypes = array(
        'gif' => 'image/gif',
        'jpe' => 'image/jpeg',
        'jpeg' => 'image/jpeg',
        'jpg' => 'image/jpeg',
        'png' => 'image/png',
        'tif' => 'image/tiff',
        'tiff' => 'image/tiff',
        'xbm' => 'image/x-xbitmap',
    );

    /* Static Methods */

    public static function getLocalFileReferences( $source, $path = null ) {
        $files = array();
        $rFlags = PREG_OFFSET_CAPTURE | PREG_SET_ORDER;
        if ( preg_match_all( '/' . self::URL_REGEX . '/', $source, $matches, $rFlags ) ) {
            foreach ( $matches as $match ) {
                $file = ( isset( $path )
                    ? rtrim( $path, '/' ) . '/'
                    : '' ) . "{$match['file'][0]}";

                // Only proceed if we can access the file
                if ( !is_null( $path ) && file_exists( $file ) ) {
                    $files[] = $file;
                }
            }
        }
        return $files;
    }

    public static function encodeImageAsDataURI( $file, $type = null, $sizeLimit = self::EMBED_SIZE_LIMIT ) {
        if ( $sizeLimit !== false && filesize( $file ) >= $sizeLimit ) {
            return false;
        }
        if ( $type === null ) {
            $type = self::getMimeType( $file );
        }
        if ( !$type ) {
            return false;
        }
        $data = base64_encode( file_get_contents( $file ) );
        return 'data:' . $type . ';base64,' . $data;
    }

    public static function getMimeType( $file ) {
        $realpath = realpath( $file );
        // Try a couple of different ways to get the mime-type of a file, in order of
        // preference
        if (
            $realpath
            && function_exists( 'finfo_file' )
            && function_exists( 'finfo_open' )
            && defined( 'FILEINFO_MIME_TYPE' )
        ) {
            // As of PHP 5.3, this is how you get the mime-type of a file; it uses the Fileinfo
            // PECL extension
            return finfo_file( finfo_open( FILEINFO_MIME_TYPE ), $realpath );
        } elseif ( function_exists( 'mime_content_type' ) ) {
            // Before this was deprecated in PHP 5.3, this was how you got the mime-type of a file
            return mime_content_type( $file );
        } else {
            // Worst-case scenario has happened, use the file extension to infer the mime-type
            $ext = strtolower( pathinfo( $file, PATHINFO_EXTENSION ) );
            if ( isset( self::$mimeTypes[$ext] ) ) {
                return self::$mimeTypes[$ext];
            }
        }
        return false;
    }

    public static function remap( $source, $local, $remote, $embedData = true ) {
        $pattern = '/((?P<embed>\s*\/\*\s*\@embed\s*\*\/)(?P<pre>[^\;\}]*))?' .
            self::URL_REGEX . '(?P<post>[^;]*)[\;]?/';
        $offset = 0;
        while ( preg_match( $pattern, $source, $match, PREG_OFFSET_CAPTURE, $offset ) ) {
            // Skip fully-qualified URLs and data URIs
            $urlScheme = parse_url( $match['file'][0], PHP_URL_SCHEME );
            if ( $urlScheme ) {
                // Move the offset to the end of the match, leaving it alone
                $offset = $match[0][1] + strlen( $match[0][0] );
                continue;
            }
            // URLs with absolute paths like /w/index.php need to be expanded
            // to absolute URLs but otherwise left alone
            if ( $match['file'][0] !== '' && $match['file'][0][0] === '/' ) {
                // Replace the file path with an expanded (possibly protocol-relative) URL
                // ...but only if wfExpandUrl() is even available.
                // This will not be the case if we're running outside of MW
                $lengthIncrease = 0;
                if ( function_exists( 'wfExpandUrl' ) ) {
                    $expanded = wfExpandUrl( $match['file'][0], PROTO_RELATIVE );
                    $origLength = strlen( $match['file'][0] );
                    $lengthIncrease = strlen( $expanded ) - $origLength;
                    $source = substr_replace( $source, $expanded,
                        $match['file'][1], $origLength
                    );
                }
                // Move the offset to the end of the match, leaving it alone
                $offset = $match[0][1] + strlen( $match[0][0] ) + $lengthIncrease;
                continue;
            }

            // Guard against double slashes, because "some/remote/../foo.png"
            // resolves to "some/remote/foo.png" on (some?) clients (bug 27052).
            if ( substr( $remote, -1 ) == '/' ) {
                $remote = substr( $remote, 0, -1 );
            }

            // Shortcuts
            $embed = $match['embed'][0];
            $pre = $match['pre'][0];
            $post = $match['post'][0];
            $query = $match['query'][0];
            $url = "{$remote}/{$match['file'][0]}";
            $file = "{$local}/{$match['file'][0]}";

            $replacement = false;

            if ( $local !== false && file_exists( $file ) ) {
                // Add version parameter as a time-stamp in ISO 8601 format,
                // using Z for the timezone, meaning GMT
                $url .= '?' . gmdate( 'Y-m-d\TH:i:s\Z', round( filemtime( $file ), -2 ) );
                // Embedding requires a bit of extra processing, so let's skip that if we can
                if ( $embedData && $embed && $match['embed'][1] > 0 ) {
                    $data = self::encodeImageAsDataURI( $file );
                    if ( $data !== false ) {
                        // Build 2 CSS properties; one which uses a base64 encoded data URI in place
                        // of the @embed comment to try and retain line-number integrity, and the
                        // other with a remapped an versioned URL and an Internet Explorer hack
                        // making it ignored in all browsers that support data URIs
                        $replacement = "{$pre}url({$data}){$post};{$pre}url({$url}){$post}!ie;";
                    }
                }
                if ( $replacement === false ) {
                    // Assume that all paths are relative to $remote, and make them absolute
                    $replacement = "{$embed}{$pre}url({$url}){$post};";
                }
            } elseif ( $local === false ) {
                // Assume that all paths are relative to $remote, and make them absolute
                $replacement = "{$embed}{$pre}url({$url}{$query}){$post};";
            }
            if ( $replacement !== false ) {
                // Perform replacement on the source
                $source = substr_replace(
                    $source, $replacement, $match[0][1], strlen( $match[0][0] )
                );
                // Move the offset to the end of the replacement in the source
                $offset = $match[0][1] + strlen( $replacement );
                continue;
            }
            // Move the offset to the end of the match, leaving it alone
            $offset = $match[0][1] + strlen( $match[0][0] );
        }
        return $source;
    }

    public static function minify( $css ) {
        return trim(
            str_replace(
                array( '; ', ': ', ' {', '{ ', ', ', '} ', ';}' ),
                array( ';', ':', '{', '{', ',', '}', '}' ),
                preg_replace( array( '/\s+/', '/\/\*.*?\*\//s' ), array( ' ', '' ), $css )
            )
        );
    }
}