diff core/lib/Drupal/Core/Asset/CssCollectionGrouper.php @ 0:4c8ae668cc8c

Initial import (non-working)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/core/lib/Drupal/Core/Asset/CssCollectionGrouper.php	Wed Nov 29 16:09:58 2017 +0000
@@ -0,0 +1,85 @@
+<?php
+
+namespace Drupal\Core\Asset;
+
+/**
+ * Groups CSS assets.
+ */
+class CssCollectionGrouper implements AssetCollectionGrouperInterface {
+
+  /**
+   * {@inheritdoc}
+   *
+   * Puts multiple items into the same group if they are groupable and if they
+   * are for the same 'media' and 'browsers'. Items of the 'file' type are
+   * groupable if their 'preprocess' flag is TRUE, and items of the 'external'
+   * type are never groupable.
+   *
+   * Also ensures that the process of grouping items does not change their
+   * relative order. This requirement may result in multiple groups for the same
+   * type, media, and browsers, if needed to accommodate other items in between.
+   */
+  public function group(array $css_assets) {
+    $groups = [];
+    // If a group can contain multiple items, we track the information that must
+    // be the same for each item in the group, so that when we iterate the next
+    // item, we can determine if it can be put into the current group, or if a
+    // new group needs to be made for it.
+    $current_group_keys = NULL;
+    // When creating a new group, we pre-increment $i, so by initializing it to
+    // -1, the first group will have index 0.
+    $i = -1;
+    foreach ($css_assets as $item) {
+      // The browsers for which the CSS item needs to be loaded is part of the
+      // information that determines when a new group is needed, but the order
+      // of keys in the array doesn't matter, and we don't want a new group if
+      // all that's different is that order.
+      ksort($item['browsers']);
+
+      // If the item can be grouped with other items, set $group_keys to an
+      // array of information that must be the same for all items in its group.
+      // If the item can't be grouped with other items, set $group_keys to
+      // FALSE. We put items into a group that can be aggregated together:
+      // whether they will be aggregated is up to the _drupal_css_aggregate()
+      // function or an
+      // override of that function specified in hook_css_alter(), but regardless
+      // of the details of that function, a group represents items that can be
+      // aggregated. Since a group may be rendered with a single HTML tag, all
+      // items in the group must share the same information that would need to
+      // be part of that HTML tag.
+      switch ($item['type']) {
+        case 'file':
+          // Group file items if their 'preprocess' flag is TRUE.
+          // Help ensure maximum reuse of aggregate files by only grouping
+          // together items that share the same 'group' value.
+          $group_keys = $item['preprocess'] ? [$item['type'], $item['group'], $item['media'], $item['browsers']] : FALSE;
+          break;
+
+        case 'external':
+          // Do not group external items.
+          $group_keys = FALSE;
+          break;
+      }
+
+      // If the group keys don't match the most recent group we're working with,
+      // then a new group must be made.
+      if ($group_keys !== $current_group_keys) {
+        $i++;
+        // Initialize the new group with the same properties as the first item
+        // being placed into it. The item's 'data', 'weight' and 'basename'
+        // properties are unique to the item and should not be carried over to
+        // the group.
+        $groups[$i] = $item;
+        unset($groups[$i]['data'], $groups[$i]['weight'], $groups[$i]['basename']);
+        $groups[$i]['items'] = [];
+        $current_group_keys = $group_keys ? $group_keys : NULL;
+      }
+
+      // Add the item to the current group.
+      $groups[$i]['items'][] = $item;
+    }
+
+    return $groups;
+  }
+
+}