Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.808
diff -u -p -r1.808 common.inc
--- includes/common.inc	12 Oct 2008 19:03:04 -0000	1.808
+++ includes/common.inc	13 Oct 2008 19:43:35 -0000
@@ -1634,6 +1634,42 @@ function drupal_get_path($type, $name) {
 function base_path() {
   return $GLOBALS['base_path'];
 }
+/**
+ * Returns a rewritten file URL. Allows you to serve files from different
+ * servers than the server on which Drupal is hosted.
+ *
+ * @param $file_path
+ *   Path to a file, relative to the root directory. E.g.: "misc/jquery.js".
+ * @param $absolute_url
+ *   Whether to generate an absolute URL or not.
+ * @param $query_string
+ *   This variable will be appended to the file url as a query string, this is
+ *   useful particularly for CSS files when you want to control their caching.
+ *   E.g.: "?string".
+ * @return
+ *   A valid file URL.
+ */
+function file_url($file_path, $absolute_url = FALSE, $query_string = FALSE) {
+  $file_url = FALSE;
+
+  foreach (module_implements('file_server') as $module) {
+    $file_url = module_invoke($module, 'file_server', 'url', $file_path, $absolute_url);
+    // If the URL rewriting function sucesfully generated a URL, we can stop
+    // trying to find a server that can serve the file.
+    if (!empty($file_url)) {
+      break;
+    }
+  }
+
+  // Always fall back to Drupal's default file server, to guarantee a working
+  // file URL.
+  if (empty($file_url)) {
+    $prefix = isset($absolute_url) ? $GLOBALS['base_url'] . '/' : base_path();
+    $file_url = $prefix . $file_path;
+  }
+
+  return $file_url . $query_string;
+}
 
 /**
  * Add a <link> tag to the page's HEAD.
@@ -1785,15 +1821,15 @@ function drupal_get_css($css = NULL) {
             // If a CSS file is not to be preprocessed and it's a module CSS file, it needs to *always* appear at the *top*,
             // regardless of whether preprocessing is on or off.
             if (!$preprocess && $type == 'module') {
-              $no_module_preprocess .= '<link type="text/css" rel="stylesheet" media="' . $media . '" href="' . base_path() . $file . $query_string . '" />' . "\n";
+              $no_module_preprocess .= '<link type="text/css" rel="stylesheet" media="' . $media . '" href="' . file_url($file, FALSE, $query_string) . '" />' . "\n";
             }
             // If a CSS file is not to be preprocessed and it's a theme CSS file, it needs to *always* appear at the *bottom*,
             // regardless of whether preprocessing is on or off.
             elseif (!$preprocess && $type == 'theme') {
-              $no_theme_preprocess .= '<link type="text/css" rel="stylesheet" media="' . $media . '" href="' . base_path() . $file . $query_string . '" />' . "\n";
+              $no_theme_preprocess .= '<link type="text/css" rel="stylesheet" media="' . $media . '" href="' . file_url($file, FALSE, $query_string) . '" />' . "\n";
             }
             else {
-              $output .= '<link type="text/css" rel="stylesheet" media="' . $media . '" href="' . base_path() . $file . $query_string . '" />' . "\n";
+              $output .= '<link type="text/css" rel="stylesheet" media="' . $media . '" href="' . file_url($file, FALSE, $query_string) . '" />' . "\n";
             }
           }
         }
@@ -1803,7 +1839,7 @@ function drupal_get_css($css = NULL) {
     if ($is_writable && $preprocess_css) {
       $filename = md5(serialize($types) . $query_string) . '.css';
       $preprocess_file = drupal_build_css_cache($types, $filename);
-      $output .= '<link type="text/css" rel="stylesheet" media="' . $media . '" href="' . base_path() . $preprocess_file . '" />' . "\n";
+      $output .= '<link type="text/css" rel="stylesheet" media="' . $media . '" href="' . file_url($preprocess_file) . '" />' . "\n";
     }
   }
 
@@ -2137,7 +2173,8 @@ function drupal_get_js($scope = 'header'
         // Additionally, go through any remaining scripts if JS preprocessing is on and output the non-cached ones.
         foreach ($data as $path => $info) {
           if (!$info['preprocess'] || !$is_writable || !$preprocess_js) {
-            $no_preprocess[$type] .= '<script type="text/javascript"' . ($info['defer'] ? ' defer="defer"' : '') . ' src="' . base_path() . $path . ($info['cache'] ? $query_string : '?' . REQUEST_TIME) . "\"></script>\n";
+            $no_preprocess[$type] .= '<script type="text/javascript"' . ($info['defer'] ? ' defer="defer"' : '') . ' src="' . file_url($path) . ($info['cache'] ? $query_string : '?' . REQUEST_TIME) . "\"></script>\n";
+
           }
           else {
             $files[$path] = $info;
Index: includes/file.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/file.inc,v
retrieving revision 1.139
diff -u -p -r1.139 file.inc
--- includes/file.inc	12 Oct 2008 04:30:05 -0000	1.139
+++ includes/file.inc	13 Oct 2008 19:43:35 -0000
@@ -98,7 +98,7 @@ function file_create_url($path) {
   }
   switch (variable_get('file_downloads', FILE_DOWNLOADS_PUBLIC)) {
     case FILE_DOWNLOADS_PUBLIC:
-      return $GLOBALS['base_url'] . '/' . file_directory_path() . '/' . str_replace('\\', '/', $path);
+      return file_url(file_directory_path() . '/' . str_replace('\\', '/', $path), TRUE);
     case FILE_DOWNLOADS_PRIVATE:
       return url('system/files/' . $path, array('absolute' => TRUE));
   }
Index: includes/theme.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/theme.inc,v
retrieving revision 1.438
diff -u -p -r1.438 theme.inc
--- includes/theme.inc	12 Oct 2008 04:30:05 -0000	1.438
+++ includes/theme.inc	13 Oct 2008 19:43:35 -0000
@@ -934,24 +934,25 @@ function theme_get_setting($setting_name
 
     if ($settings['toggle_logo']) {
       if ($settings['default_logo']) {
-        $settings['logo'] = base_path() . dirname($theme_object->filename) . '/logo.png';
+        $settings['logo'] = file_url(dirname($theme_object->filename) . '/logo.png');
+
       }
       elseif ($settings['logo_path']) {
-        $settings['logo'] = base_path() . $settings['logo_path'];
+        $settings['logo'] = file_url($settings['logo_path']);
       }
     }
 
     if ($settings['toggle_favicon']) {
       if ($settings['default_favicon']) {
         if (file_exists($favicon = dirname($theme_object->filename) . '/favicon.ico')) {
-          $settings['favicon'] = base_path() . $favicon;
+          $settings['favicon'] = file_url($favicon);
         }
         else {
-          $settings['favicon'] = base_path() . 'misc/favicon.ico';
+          $settings['favicon'] = file_url('misc/favicon.ico');
         }
       }
       elseif ($settings['favicon_path']) {
-        $settings['favicon'] = base_path() . $settings['favicon_path'];
+        $settings['favicon'] = file_url($settings['favicon_path']);
       }
       else {
         $settings['toggle_favicon'] = FALSE;
@@ -1169,8 +1170,7 @@ function theme_links($links, $attributes
 function theme_image($path, $alt = '', $title = '', $attributes = NULL, $getsize = TRUE) {
   if (!$getsize || (is_file($path) && (list($width, $height, $type, $image_attributes) = @getimagesize($path)))) {
     $attributes = drupal_attributes($attributes);
-    $url = (url($path) == $path) ? $path : (base_path() . $path);
-    return '<img src="' . check_url($url) . '" alt="' . check_plain($alt) . '" title="' . check_plain($title) . '" ' . (isset($image_attributes) ? $image_attributes : '') . $attributes . ' />';
+    return '<img src="' . check_url(file_url($path)) . '" alt="' . check_plain($alt) . '" title="' . check_plain($title) . '" ' . (isset($image_attributes) ? $image_attributes : '') . $attributes . ' />';
   }
 }