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