first import

Signed-off-by: bachy <git@g-u-i.net>

modules/book/views_plugin_argument_default_book_root.inc

@@ -0,0 +1,21 @@
+<?php
+/**
+ * @file
+ * Contains the book root from current node argument default plugin.
+ */
+
+/**
+ * Default argument plugin to get the current node's book root.
+ */
+class views_plugin_argument_default_book_root extends views_plugin_argument_default_node {
+  function get_argument() {
+    // Use the argument_default_node plugin to get the nid argument.
+    $nid = parent::get_argument();
+    if (!empty($nid)) {
+      $node = node_load($nid);
+      if (isset($node->book['bid'])) {
+        return $node->book['bid'];
+      }
+    }
+  }
+}