diff core/lib/Drupal/Core/Render/BubbleableMetadata.php @ 0:4c8ae668cc8c

Initial import (non-working)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/core/lib/Drupal/Core/Render/BubbleableMetadata.php	Wed Nov 29 16:09:58 2017 +0000
@@ -0,0 +1,177 @@
+<?php
+
+namespace Drupal\Core\Render;
+
+use Drupal\Component\Utility\NestedArray;
+use Drupal\Core\Cache\CacheableMetadata;
+
+/**
+ * Value object used for bubbleable rendering metadata.
+ *
+ * @see \Drupal\Core\Render\RendererInterface::render()
+ */
+class BubbleableMetadata extends CacheableMetadata implements AttachmentsInterface {
+
+  use AttachmentsTrait;
+
+  /**
+   * Merges the values of another bubbleable metadata object with this one.
+   *
+   * @param \Drupal\Core\Cache\CacheableMetadata $other
+   *   The other bubbleable metadata object.
+   *
+   * @return static
+   *   A new bubbleable metadata object, with the merged data.
+   */
+  public function merge(CacheableMetadata $other) {
+    $result = parent::merge($other);
+
+    // This is called many times per request, so avoid merging unless absolutely
+    // necessary.
+    if ($other instanceof BubbleableMetadata) {
+      if (empty($this->attachments)) {
+        $result->attachments = $other->attachments;
+      }
+      elseif (empty($other->attachments)) {
+        $result->attachments = $this->attachments;
+      }
+      else {
+        $result->attachments = static::mergeAttachments($this->attachments, $other->attachments);
+      }
+    }
+
+    return $result;
+  }
+
+  /**
+   * Applies the values of this bubbleable metadata object to a render array.
+   *
+   * @param array &$build
+   *   A render array.
+   */
+  public function applyTo(array &$build) {
+    parent::applyTo($build);
+    $build['#attached'] = $this->attachments;
+  }
+
+  /**
+   * Creates a bubbleable metadata object with values taken from a render array.
+   *
+   * @param array $build
+   *   A render array.
+   *
+   * @return static
+   */
+  public static function createFromRenderArray(array $build) {
+    $meta = parent::createFromRenderArray($build);
+    $meta->attachments = (isset($build['#attached'])) ? $build['#attached'] : [];
+    return $meta;
+  }
+
+  /**
+   * Creates a bubbleable metadata object from a depended object.
+   *
+   * @param \Drupal\Core\Cache\CacheableDependencyInterface|mixed $object
+   *   The object whose cacheability metadata to retrieve. If it implements
+   *   CacheableDependencyInterface, its cacheability metadata will be used,
+   *   otherwise, the passed in object must be assumed to be uncacheable, so
+   *   max-age 0 is set.
+   *
+   * @return static
+   */
+  public static function createFromObject($object) {
+    $meta = parent::createFromObject($object);
+
+    if ($object instanceof AttachmentsInterface) {
+      $meta->attachments = $object->getAttachments();
+    }
+
+    return $meta;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function addCacheableDependency($other_object) {
+    parent::addCacheableDependency($other_object);
+
+    if ($other_object instanceof AttachmentsInterface) {
+      $this->addAttachments($other_object->getAttachments());
+    }
+
+    return $this;
+  }
+
+  /**
+   * Merges two attachments arrays (which live under the '#attached' key).
+   *
+   * The values under the 'drupalSettings' key are merged in a special way, to
+   * match the behavior of:
+   *
+   * @code
+   *   jQuery.extend(true, {}, $settings_items[0], $settings_items[1], ...)
+   * @endcode
+   *
+   * This means integer indices are preserved just like string indices are,
+   * rather than re-indexed as is common in PHP array merging.
+   *
+   * Example:
+   * @code
+   * function module1_page_attachments(&$page) {
+   *   $page['a']['#attached']['drupalSettings']['foo'] = ['a', 'b', 'c'];
+   * }
+   * function module2_page_attachments(&$page) {
+   *   $page['#attached']['drupalSettings']['foo'] = ['d'];
+   * }
+   * // When the page is rendered after the above code, and the browser runs the
+   * // resulting <SCRIPT> tags, the value of drupalSettings.foo is
+   * // ['d', 'b', 'c'], not ['a', 'b', 'c', 'd'].
+   * @endcode
+   *
+   * By following jQuery.extend() merge logic rather than common PHP array merge
+   * logic, the following are ensured:
+   * - Attaching JavaScript settings is idempotent: attaching the same settings
+   *   twice does not change the output sent to the browser.
+   * - If pieces of the page are rendered in separate PHP requests and the
+   *   returned settings are merged by JavaScript, the resulting settings are
+   *   the same as if rendered in one PHP request and merged by PHP.
+   *
+   * @param array $a
+   *   An attachments array.
+   * @param array $b
+   *   Another attachments array.
+   *
+   * @return array
+   *   The merged attachments array.
+   */
+  public static function mergeAttachments(array $a, array $b) {
+    // If both #attached arrays contain drupalSettings, then merge them
+    // correctly; adding the same settings multiple times needs to behave
+    // idempotently.
+    if (!empty($a['drupalSettings']) && !empty($b['drupalSettings'])) {
+      $drupalSettings = NestedArray::mergeDeepArray([$a['drupalSettings'], $b['drupalSettings']], TRUE);
+      // No need for re-merging them.
+      unset($a['drupalSettings']);
+      unset($b['drupalSettings']);
+    }
+    // Optimize merging of placeholders: no need for deep merging.
+    if (!empty($a['placeholders']) && !empty($b['placeholders'])) {
+      $placeholders = $a['placeholders'] + $b['placeholders'];
+      // No need for re-merging them.
+      unset($a['placeholders']);
+      unset($b['placeholders']);
+    }
+    // Apply the normal merge.
+    $a = array_merge_recursive($a, $b);
+    if (isset($drupalSettings)) {
+      // Save the custom merge for the drupalSettings.
+      $a['drupalSettings'] = $drupalSettings;
+    }
+    if (isset($placeholders)) {
+      // Save the custom merge for the placeholders.
+      $a['placeholders'] = $placeholders;
+    }
+    return $a;
+  }
+
+}