Chris@0: <?php
Chris@0: 
Chris@0: namespace Drupal\Core\Asset;
Chris@0: 
Chris@18: use Drupal\Core\File\FileSystemInterface;
Chris@0: use Drupal\Core\State\StateInterface;
Chris@0: 
Chris@0: /**
Chris@0:  * Optimizes CSS assets.
Chris@0:  */
Chris@0: class CssCollectionOptimizer implements AssetCollectionOptimizerInterface {
Chris@0: 
Chris@0:   /**
Chris@0:    * A CSS asset grouper.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Asset\CssCollectionGrouper
Chris@0:    */
Chris@0:   protected $grouper;
Chris@0: 
Chris@0:   /**
Chris@0:    * A CSS asset optimizer.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Asset\CssOptimizer
Chris@0:    */
Chris@0:   protected $optimizer;
Chris@0: 
Chris@0:   /**
Chris@0:    * An asset dumper.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Asset\AssetDumper
Chris@0:    */
Chris@0:   protected $dumper;
Chris@0: 
Chris@0:   /**
Chris@0:    * The state key/value store.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\State\StateInterface
Chris@0:    */
Chris@0:   protected $state;
Chris@0: 
Chris@0:   /**
Chris@18:    * The file system service.
Chris@18:    *
Chris@18:    * @var \Drupal\Core\File\FileSystemInterface
Chris@18:    */
Chris@18:   protected $fileSystem;
Chris@18: 
Chris@18:   /**
Chris@0:    * Constructs a CssCollectionOptimizer.
Chris@0:    *
Chris@0:    * @param \Drupal\Core\Asset\AssetCollectionGrouperInterface $grouper
Chris@0:    *   The grouper for CSS assets.
Chris@0:    * @param \Drupal\Core\Asset\AssetOptimizerInterface $optimizer
Chris@0:    *   The optimizer for a single CSS asset.
Chris@0:    * @param \Drupal\Core\Asset\AssetDumperInterface $dumper
Chris@0:    *   The dumper for optimized CSS assets.
Chris@0:    * @param \Drupal\Core\State\StateInterface $state
Chris@0:    *   The state key/value store.
Chris@18:    * @param \Drupal\Core\File\FileSystemInterface $file_system
Chris@18:    *   The file system service.
Chris@0:    */
Chris@18:   public function __construct(AssetCollectionGrouperInterface $grouper, AssetOptimizerInterface $optimizer, AssetDumperInterface $dumper, StateInterface $state, FileSystemInterface $file_system = NULL) {
Chris@0:     $this->grouper = $grouper;
Chris@0:     $this->optimizer = $optimizer;
Chris@0:     $this->dumper = $dumper;
Chris@0:     $this->state = $state;
Chris@18:     if (!$file_system) {
Chris@18:       @trigger_error('The file_system service must be passed to CssCollectionOptimizer::__construct(), it is required before Drupal 9.0.0. See https://www.drupal.org/node/3006851.', E_USER_DEPRECATED);
Chris@18:       $file_system = \Drupal::service('file_system');
Chris@18:     }
Chris@18:     $this->fileSystem = $file_system;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    *
Chris@0:    * The cache file name is retrieved on a page load via a lookup variable that
Chris@0:    * contains an associative array. The array key is the hash of the file names
Chris@0:    * in $css while the value is the cache file name. The cache file is generated
Chris@0:    * in two cases. First, if there is no file name value for the key, which will
Chris@0:    * happen if a new file name has been added to $css or after the lookup
Chris@0:    * variable is emptied to force a rebuild of the cache. Second, the cache file
Chris@0:    * is generated if it is missing on disk. Old cache files are not deleted
Chris@0:    * immediately when the lookup variable is emptied, but are deleted after a
Chris@0:    * configurable period (@code system.performance.stale_file_threshold @endcode)
Chris@0:    * to ensure that files referenced by a cached page will still be available.
Chris@0:    */
Chris@0:   public function optimize(array $css_assets) {
Chris@0:     // Group the assets.
Chris@0:     $css_groups = $this->grouper->group($css_assets);
Chris@0: 
Chris@0:     // Now optimize (concatenate + minify) and dump each asset group, unless
Chris@0:     // that was already done, in which case it should appear in
Chris@0:     // drupal_css_cache_files.
Chris@0:     // Drupal contrib can override this default CSS aggregator to keep the same
Chris@0:     // grouping, optimizing and dumping, but change the strategy that is used to
Chris@0:     // determine when the aggregate should be rebuilt (e.g. mtime, HTTPS …).
Chris@0:     $map = $this->state->get('drupal_css_cache_files') ?: [];
Chris@0:     $css_assets = [];
Chris@0:     foreach ($css_groups as $order => $css_group) {
Chris@0:       // We have to return a single asset, not a group of assets. It is now up
Chris@0:       // to one of the pieces of code in the switch statement below to set the
Chris@0:       // 'data' property to the appropriate value.
Chris@0:       $css_assets[$order] = $css_group;
Chris@0:       unset($css_assets[$order]['items']);
Chris@0: 
Chris@0:       switch ($css_group['type']) {
Chris@0:         case 'file':
Chris@0:           // No preprocessing, single CSS asset: just use the existing URI.
Chris@0:           if (!$css_group['preprocess']) {
Chris@0:             $uri = $css_group['items'][0]['data'];
Chris@0:             $css_assets[$order]['data'] = $uri;
Chris@0:           }
Chris@0:           // Preprocess (aggregate), unless the aggregate file already exists.
Chris@0:           else {
Chris@0:             $key = $this->generateHash($css_group);
Chris@0:             $uri = '';
Chris@0:             if (isset($map[$key])) {
Chris@0:               $uri = $map[$key];
Chris@0:             }
Chris@0:             if (empty($uri) || !file_exists($uri)) {
Chris@0:               // Optimize each asset within the group.
Chris@0:               $data = '';
Chris@0:               foreach ($css_group['items'] as $css_asset) {
Chris@0:                 $data .= $this->optimizer->optimize($css_asset);
Chris@0:               }
Chris@0:               // Per the W3C specification at
Chris@0:               // http://www.w3.org/TR/REC-CSS2/cascade.html#at-import, @import
Chris@0:               // rules must precede any other style, so we move those to the
Chris@0:               // top.
Chris@0:               $regexp = '/@import[^;]+;/i';
Chris@0:               preg_match_all($regexp, $data, $matches);
Chris@0:               $data = preg_replace($regexp, '', $data);
Chris@0:               $data = implode('', $matches[0]) . $data;
Chris@0:               // Dump the optimized CSS for this group into an aggregate file.
Chris@0:               $uri = $this->dumper->dump($data, 'css');
Chris@0:               // Set the URI for this group's aggregate file.
Chris@0:               $css_assets[$order]['data'] = $uri;
Chris@0:               // Persist the URI for this aggregate file.
Chris@0:               $map[$key] = $uri;
Chris@0:               $this->state->set('drupal_css_cache_files', $map);
Chris@0:             }
Chris@0:             else {
Chris@0:               // Use the persisted URI for the optimized CSS file.
Chris@0:               $css_assets[$order]['data'] = $uri;
Chris@0:             }
Chris@0:             $css_assets[$order]['preprocessed'] = TRUE;
Chris@0:           }
Chris@0:           break;
Chris@0: 
Chris@0:         case 'external':
Chris@0:           // We don't do any aggregation and hence also no caching for external
Chris@0:           // CSS assets.
Chris@0:           $uri = $css_group['items'][0]['data'];
Chris@0:           $css_assets[$order]['data'] = $uri;
Chris@0:           break;
Chris@0:       }
Chris@0:     }
Chris@0: 
Chris@0:     return $css_assets;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Generate a hash for a given group of CSS assets.
Chris@0:    *
Chris@0:    * @param array $css_group
Chris@0:    *   A group of CSS assets.
Chris@0:    *
Chris@0:    * @return string
Chris@0:    *   A hash to uniquely identify the given group of CSS assets.
Chris@0:    */
Chris@0:   protected function generateHash(array $css_group) {
Chris@0:     $css_data = [];
Chris@0:     foreach ($css_group['items'] as $css_file) {
Chris@0:       $css_data[] = $css_file['data'];
Chris@0:     }
Chris@0:     return hash('sha256', serialize($css_data));
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function getAll() {
Chris@0:     return $this->state->get('drupal_css_cache_files');
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function deleteAll() {
Chris@0:     $this->state->delete('drupal_css_cache_files');
Chris@0: 
Chris@0:     $delete_stale = function ($uri) {
Chris@0:       // Default stale file threshold is 30 days.
Chris@0:       if (REQUEST_TIME - filemtime($uri) > \Drupal::config('system.performance')->get('stale_file_threshold')) {
Chris@18:         $this->fileSystem->delete($uri);
Chris@0:       }
Chris@0:     };
Chris@0:     file_scan_directory('public://css', '/.*/', ['callback' => $delete_stale]);
Chris@0:   }
Chris@0: 
Chris@0: }