Minify_CSS_UriRewriter.php

Go to the documentation of this file.

<?php
class Minify_CSS_UriRewriter {
     
     public static $debugText = '';
     
     public static function rewrite($css, $currentDir, $docRoot = null, $symlinks = array()) 
     {
          self::$_docRoot = self::_realpath(
               $docRoot ? $docRoot : $_SERVER['DOCUMENT_ROOT']
          );
          self::$_currentDir = self::_realpath($currentDir);
          self::$_symlinks = array();
          
          // normalize symlinks
          foreach ($symlinks as $link => $target) {
               $link = ($link === '//')
                    ? self::$_docRoot
                    : str_replace('//', self::$_docRoot . '/', $link);
               $link = strtr($link, '/', DIRECTORY_SEPARATOR);
               self::$_symlinks[$link] = self::_realpath($target);
          }
          
          self::$debugText .= "docRoot  : " . self::$_docRoot . "\n"
                                . "currentDir : " . self::$_currentDir . "\n";
          if (self::$_symlinks) {
               self::$debugText .= "symlinks : " . var_export(self::$_symlinks, 1) . "\n";
          }
          self::$debugText .= "\n";
          
          $css = self::_trimUrls($css);
          
          // rewrite
          $css = preg_replace_callback('/@import\\s+([\'"])(.*?)[\'"]/'
               ,array(self::$className, '_processUriCB'), $css);
          $css = preg_replace_callback('/url\\(\\s*([^\\)\\s]+)\\s*\\)/'
               ,array(self::$className, '_processUriCB'), $css);
        return $css;
     }
     
     public static function prepend($css, $path)
     {
          self::$_prependPath = $path;
          
          $css = self::_trimUrls($css);
          
          // append
          $css = preg_replace_callback('/@import\\s+([\'"])(.*?)[\'"]/'
               ,array(self::$className, '_processUriCB'), $css);
          $css = preg_replace_callback('/url\\(\\s*([^\\)\\s]+)\\s*\\)/'
               ,array(self::$className, '_processUriCB'), $css);

          self::$_prependPath = null;
          return $css;
     }
     
     public static function rewriteRelative($uri, $realCurrentDir, $realDocRoot, $symlinks = array())
     {
          // prepend path with current dir separator (OS-independent)
          $path = strtr($realCurrentDir, '/', DIRECTORY_SEPARATOR)  
               . DIRECTORY_SEPARATOR . strtr($uri, '/', DIRECTORY_SEPARATOR);
          
          self::$debugText .= "file-relative URI  : {$uri}\n"
                                . "path prepended  : {$path}\n";
          
          // "unresolve" a symlink back to doc root
          foreach ($symlinks as $link => $target) {
               if (0 === strpos($path, $target)) {
                    // replace $target with $link
                    $path = $link . substr($path, strlen($target));
                    
                    self::$debugText .= "symlink unresolved : {$path}\n";
                    
                    break;
               }
          }
          // strip doc root
          $path = substr($path, strlen($realDocRoot));
          
          self::$debugText .= "docroot stripped   : {$path}\n";
          
          // fix to root-relative URI
          $uri = strtr($path, '/\\', '//');
          $uri = self::removeDots($uri);
       
          self::$debugText .= "traversals removed : {$uri}\n\n";
          
          return $uri;
     }

     public static function removeDots($uri)
     {
          $uri = str_replace('/./', '/', $uri);
          // inspired by patch from Oleg Cherniy
          $i=0;
          do {
               $uri = preg_replace('@/[^/]+/\\.\\./@', '/', $uri, 1, $changed);
          } while ($changed && $i++<100);
          return $uri;
     }
     
     protected static $className = 'Minify_CSS_UriRewriter';

     protected static function _realpath($path)
     {
          $realPath = realpath($path);
          if ($realPath !== false) {
               $path = $realPath;
          }
          return rtrim($path, '/\\');
     }

     private static $_currentDir = '';

     private static $_docRoot = '';

     private static $_symlinks = array();

     private static $_prependPath = null;

     private static function _trimUrls($css)
     {
          return preg_replace('/
               url\\(      # url(
               \\s*
               ([^\\)]+?)  # 1 = URI (assuming does not contain ")")
               \\s*
               \\)        # )
          /x', 'url($1)', $css);
     }

     private static function _processUriCB($m)
     {
          // $m matched either '/@import\\s+([\'"])(.*?)[\'"]/' or '/url\\(\\s*([^\\)\\s]+)\\s*\\)/'
          $isImport = ($m[0][0] === '@');
          // determine URI and the quote character (if any)
          if ($isImport) {
               $quoteChar = $m[1];
               $uri = $m[2];
          } else {
               // $m[1] is either quoted or not
               $quoteChar = ($m[1][0] === "'" || $m[1][0] === '"')
                    ? $m[1][0]
                    : '';
               $uri = ($quoteChar === '')
                    ? $m[1]
                    : substr($m[1], 1, strlen($m[1]) - 2);
          }
          // analyze URI
          if ('/' !== $uri[0]                  // root-relative
               && false === strpos($uri, '//')  // protocol (non-data)
               && 0 !== strpos($uri, 'data:')   // data protocol
          ) {
               // URI is file-relative: rewrite depending on options
               if (self::$_prependPath === null) {
                    $uri = self::rewriteRelative($uri, self::$_currentDir, self::$_docRoot, self::$_symlinks);
               } else {
                    $uri = self::$_prependPath . $uri;
                    if ($uri[0] === '/') {
                         $root = '';
                         $rootRelative = $uri;
                         $uri = $root . self::removeDots($rootRelative);
                    } elseif (preg_match('@^((https?\:)?//([^/]+))/@', $uri, $m) && (false !== strpos($m[3], '.'))) {
                         $root = $m[1];
                         $rootRelative = substr($uri, strlen($root));
                         $uri = $root . self::removeDots($rootRelative);
                    }
               }
          }
          return $isImport
               ? "@import {$quoteChar}{$uri}{$quoteChar}"
               : "url({$quoteChar}{$uri}{$quoteChar})";
     }
}