first import

sites/all/modules/context/plugins/context_condition_bookroot.inc

@@ -0,0 +1,19 @@
+<?php
+
+/**
+ * Set the context on the basis of the node type of page's book root.
+ */
+class context_condition_bookroot extends context_condition_node {
+  function execute($node, $op) {
+    if ($this->condition_used() && !empty($node->book['bid'])) {
+      $type = db_select('node')
+        ->fields('node', array('type'))
+        ->condition('nid', $node->book['nid'])
+        ->execute()
+        ->fetchField();
+      $book = new stdClass();
+      $book->type = $type;
+      parent::execute($book, $op);
+    }
+  }
+}