trait QueryTrait

trait QueryTrait {
    
    /**
     * The workspace manager.
     *
     * @var \Drupal\workspaces\WorkspaceManagerInterface
     */
    protected $workspaceManager;
    
    /**
     * Constructs a Query object.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
     *   The entity type definition.
     * @param string $conjunction
     *   - AND: all of the conditions on the query need to match.
     *   - OR: at least one of the conditions on the query need to match.
     * @param \Drupal\Core\Database\Connection $connection
     *   The database connection to run the query against.
     * @param array $namespaces
     *   List of potential namespaces of the classes belonging to this query.
     * @param \Drupal\workspaces\WorkspaceManagerInterface $workspace_manager
     *   The workspace manager.
     */
    public function __construct(EntityTypeInterface $entity_type, $conjunction, Connection $connection, array $namespaces, WorkspaceManagerInterface $workspace_manager) {
        parent::__construct($entity_type, $conjunction, $connection, $namespaces);
        $this->workspaceManager = $workspace_manager;
    }
    
    /**
     * {@inheritdoc}
     */
    public function prepare() {
        parent::prepare();
        // Do not alter entity revision queries.
        // @todo How about queries for the latest revision? Should we alter them to
        //   look for the latest workspace-specific revision?
        if ($this->allRevisions) {
            return $this;
        }
        // Only alter the query if the active workspace is not the default one and
        // the entity type is supported.
        if ($this->workspaceManager
            ->hasActiveWorkspace() && $this->workspaceManager
            ->isEntityTypeSupported($this->entityType)) {
            $active_workspace = $this->workspaceManager
                ->getActiveWorkspace();
            $this->sqlQuery
                ->addMetaData('active_workspace_id', $active_workspace->id());
            $this->sqlQuery
                ->addMetaData('simple_query', FALSE);
            // LEFT JOIN 'workspace_association' to the base table of the query so we
            // can properly include live content along with a possible workspace
            // revision.
            $id_field = $this->entityType
                ->getKey('id');
            $this->sqlQuery
                ->leftJoin('workspace_association', 'workspace_association', "%alias.target_entity_type_id = '{$this->entityTypeId}' AND %alias.target_entity_id = base_table.{$id_field} AND %alias.workspace = '{$active_workspace->id()}'");
        }
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function isSimpleQuery() {
        // We declare that this is not a simple query in
        // \Drupal\workspaces\EntityQuery\QueryTrait::prepare(), but that's not
        // enough because the parent method can return TRUE in some circumstances.
        if ($this->sqlQuery
            ->getMetaData('active_workspace_id')) {
            return FALSE;
        }
        return parent::isSimpleQuery();
    }

}