Extended #3280964 to support Group 2.x.

Closes #3405874

modules/access_unpublished_group/src/Access/AccessUnpublishedGroupPermissions.php

+<?php
+
+namespace Drupal\access_unpublished_group\Access;
+
+use Drupal\group\Plugin\Group\Relation\GroupRelationInterface;
+use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+use Drupal\Core\Routing\RouteMatchInterface;
+use Drupal\group\Plugin\Group\Relation\GroupRelationTypeManagerInterface;
+
+/**
+ * Provides dynamic permissions for groups of different types.
+ */
+class AccessUnpublishedGroupPermissions implements ContainerInjectionInterface {
+
+  /**
+   * The route match.
+   *
+   * @var \Drupal\Core\Routing\RouteMatchInterface
+   */
+  protected $routeMatch;
+
+  /**
+   * The group content enabler plugin manager.
+   *
+   * @var \Drupal\group\Plugin\Group\Relation\GroupRelationTypeManagerInterface
+   */
+  protected $groupRelationTypeManager;
+
+  /**
+   * Constructs the AccessUnpublishedGroupPermissions object.
+   */
+  public function __construct(RouteMatchInterface $route_match, GroupRelationTypeManagerInterface $group_relation_type_manager) {
+    $this->routeMatch = $route_match;
+    $this->groupRelationTypeManager = $group_relation_type_manager;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static(
+      $container->get('current_route_match'),
+      $container->get('group_relation_type.manager')
+    );
+  }
+
+  /**
+   * Returns an array of group permissions.
+   *
+   * @return array
+   *   The group permissions.
+   *   @see \Drupal\user\PermissionHandlerInterface::getPermissions()
+   */
+  public function groupPermissions() {
+    $perms = [];
+    if (is_null($this->groupRelationTypeManager)) {
+      return [];
+    }
+    if ($group_type = $this->routeMatch->getParameter('group_type')) {
+      $plugins = $this->groupRelationTypeManager->getInstalled($group_type);
+      foreach ($plugins as $plugin) {
+        $perms += $this->buildPermissions($plugin);
+      }
+    }
+    return $perms;
+  }
+
+  /**
+   * Returns list of group permissions for a given group content enabler plugin.
+   *
+   * @param \Drupal\group\Plugin\Group\Relation\GroupRelationInterface $plugin
+   *   The group content enabler plugin.
+   *
+   * @return array
+   *   An associative array of permission names and descriptions.
+   */
+  protected function buildPermissions(GroupRelationInterface $plugin) {
+    $permissions = [];
+    $permissions['access_unpublished_group_' . $plugin->getPluginId()] = [
+      'title' => 'Access unpublished ' . $plugin->getPluginDefinition()->get('label') ?? '',
+    ];
+    return $permissions;
+  }
+
+}