Add children_count() to ORM_MPTT

2 files changed, 53 insertions, 2 deletions

diff --git a/core/libraries/ORM_MPTT.php b/core/libraries/ORM_MPTT.php
index 83190d4a..f79ea910 100644
--- a/core/libraries/ORM_MPTT.php
+++ b/core/libraries/ORM_MPTT.php
@@ -36,6 +36,7 @@ class ORM_MPTT_Core extends ORM {
   private $parent = null;
   private $parents = null;
   private $children = null;
+  private $children_count = null;
 
   function __construct($id=null) {
     parent::__construct($id);
@@ -102,22 +103,47 @@ class ORM_MPTT_Core extends ORM {
   /**
    * Return all of the children of this node, ordered by id.
    *
+   * @chainable
+   * @param   integer  SQL limit
+   * @param   integer  SQL offset
    * @return array ORM
    */
-  function children() {
+  function children($limit=NULL, $offset=0) {
     if (!isset($this->children)) {
       $this->children =
         $this->where("parent_id", $this->id)
         ->orderby("id", "ASC")
-        ->find_all();
+        ->find_all($limit, $offset);
     }
     return $this->children;
   }
 
+  /**
+   * Return all of the children of this node, ordered by id.
+   *
+   * @chainable
+   * @param   integer  SQL limit
+   * @param   integer  SQL offset
+   * @return array ORM
+   */
+  function children_count() {
+    if (!isset($this->children_count)) {
+      $this->children_count =
+        $this->where("parent_id", $this->id)
+        ->orderby("id", "ASC")
+        ->count_all();
+    }
+    return $this->children_count;
+  }
+
+  /**
+   * @see ORM::reload
+   */
   function reload() {
     $this->parent = null;
     $this->parents = null;
     $this->children = null;
+    $this->children_count = null;
     return parent::reload();
   }
 
diff --git a/core/tests/ORM_MPTT_Test.php b/core/tests/ORM_MPTT_Test.php
index a543c1cd..d66006f5 100644
--- a/core/tests/ORM_MPTT_Test.php
+++ b/core/tests/ORM_MPTT_Test.php
@@ -69,4 +69,29 @@ class ORM_MPTT_Test extends Unit_Test_Case {
     }
     $this->assert_equal(array($inner1->id, $inner2->id), $child_ids);
   }
+
+  public function children_limit_test() {
+    $outer = ORM::factory("item");
+    $outer->add_to_parent(1);
+
+    $inner1 = ORM::factory("item");
+    $inner1->add_to_parent($outer->id);
+
+    $inner2 = ORM::factory("item");
+    $inner2->add_to_parent($outer->id);
+
+    $this->assert_equal(array($inner2->id => null), $outer->children(1, 1)->select_list('id'));
+  }
+
+  public function children_count_test() {
+    $outer = ORM::factory("item");
+    $outer->add_to_parent(1);
+
+    $inner1 = ORM::factory("item");
+    $inner1->add_to_parent($outer->id);
+
+    $inner2 = ORM::factory("item");
+    $inner2->add_to_parent($outer->id);
+    $this->assert_equal(2, $outer->children_count());
+  }
 }