[glibmm] Implemented reference counting for BalancedTree.

[Jonathon Jongsma <jjongsma src gnome org>]

commit 199929dd8a4050776332813e7125ce5bba923e5c
Author: Szilárd Pfeiffer <mailbox pfeifferszilard hu>
Date:   Tue Jan 5 22:40:07 2010 -0600

    Implemented reference counting for BalancedTree.

 glib/src/btree.hg |   40 ++++++++++++++++++++++++++++++++++++++++
 1 files changed, 40 insertions(+), 0 deletions(-)
---
diff --git a/glib/src/btree.hg b/glib/src/btree.hg
index a815ae1..0061819 100644
--- a/glib/src/btree.hg
+++ b/glib/src/btree.hg
@@ -38,6 +38,7 @@ public:
   typedef sigc::slot<bool, const K&, const V&> TraverseFunc;
   typedef sigc::slot<int, const K&, const K&> CompareFunc;
 
+protected:
   BalancedTree() :
     key_compare_slot(sigc::ptr_fun(key_compare))
   {
@@ -50,6 +51,17 @@ public:
     gobject_ = g_tree_new_full(on_compare_tree, &key_compare_slot, on_destroy_key, on_destroy_value);
   }
 
+public:
+  static Glib::RefPtr< BalancedTree<K, V> > create()
+  {
+    return Glib::RefPtr< BalancedTree<K, V> >(new BalancedTree());
+  }
+
+  static Glib::RefPtr< BalancedTree<K, V> > create(const CompareFunc &key_compare_slot)
+  {
+    return Glib::RefPtr< BalancedTree<K, V> >(new BalancedTree(key_compare_slot));
+  }
+
   ~BalancedTree()
   {
     g_tree_destroy(gobject_);
@@ -69,6 +81,34 @@ public:
   }
 
 /**
+ * reference:
+ *
+ * Increments the reference count of tree by one.  It is safe to call
+ * this function from any thread.
+ **/
+  void reference()
+  {
+    g_tree_ref(gobject_);
+  }
+  _IGNORE(g_tree_ref)
+
+/**
+ * unreference:
+ *
+ * Decrements the reference count of tree by one.  If the reference count
+ * drops to 0, all keys and values will be destroyed (if destroy
+ * functions were specified) and all memory allocated by @tree will be
+ * released.
+ *
+ * It is safe to call this function from any thread.
+ **/
+  void unreference()
+  {
+    g_tree_unref(gobject_);
+  }
+  _IGNORE(g_tree_unref)
+
+/**
  * insert:
  * @key: the key to insert.
  * @value: the value corresponding to the key.