function drupal_build_css_cache

Aggregate and optimize CSS files, putting them in the files directory.

Parameters

$types: An array of types of CSS files (e.g., screen, print) to aggregate and compress into one file.

$filename: The name of the aggregate CSS file.

Return value

The name of the CSS file.

Related topics

File

includes/common.inc, line 1655

Common functions that many Drupal modules will need to reference.

Code

function drupal_build_css_cache($types, $filename) {
  $data = '';

  // Create the css/ within the files folder.
  $csspath = file_create_path('css');
  file_check_directory($csspath, FILE_CREATE_DIRECTORY);
  if (!file_exists($csspath . '/' . $filename)) {

    // Build aggregate CSS file.
    foreach ($types as $type) {
      foreach ($type as $file => $cache) {
        if ($cache) {
          $contents = file_get_contents($file);

          // Remove multiple charset declarations for standards compliance (and fixing Safari problems)
          $contents = preg_replace('/^@charset\\s+[\'"](\\S*)\\b[\'"];/i', '', $contents);

          // Return the path to where this CSS file originated from, stripping off the name of the file at the end of the path.
          $path = base_path() . substr($file, 0, strrpos($file, '/')) . '/';

          // Wraps all @import arguments in url().
          $contents = preg_replace('/@import\\s+(?!url)[\'"]?(\\S*)\\b[\'"]?/i', '@import url("\\1")', $contents);

          // Fix all paths within this CSS file, ignoring absolute paths.
          $data .= preg_replace('/url\\(([\'"]?)(?![a-z]+:)/i', 'url(\\1' . $path . '\\2', $contents);
        }
      }
    }

    // @import rules must proceed any other style, so we move those to the top.
    $regexp = '/@import[^;]+;/i';
    preg_match_all($regexp, $data, $matches);
    $data = preg_replace($regexp, '', $data);
    $data = implode('', $matches[0]) . $data;

    // Perform some safe CSS optimizations.
    $data = preg_replace('<
      \\s*([@{}:;,]|\\)\\s|\\s\\()\\s* |  # Remove whitespace around separators, but keep space around parentheses.
      /\\*([^*\\\\]|\\*(?!/))+\\*/ |   # Remove comments that are not CSS hacks.
      [\\n\\r]                        # Remove line breaks.
      >x', '\\1', $data);

    // Create the CSS file.
    file_save_data($data, $csspath . '/' . $filename, FILE_EXISTS_REPLACE);
  }
  return $csspath . '/' . $filename;
}