comparison core/lib/Drupal/Core/Asset/CssCollectionOptimizer.php @ 0:4c8ae668cc8c

Initial import (non-working)

+<?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]);
+  }
+
+}