From 1d7c144967b9cd24f4fd53270c340a8accc61cab Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Fri, 26 Aug 2016 18:25:15 +0200
Subject: [PATCH] add "sameinstance()" lua binding for all shared/weak ptrs

---
 libs/lua/LuaBridge/detail/CFunctions.h | 33 +++++++++++++++++++++++++-
 libs/lua/LuaBridge/detail/Namespace.h  | 18 +++++++++++++-
 2 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/libs/lua/LuaBridge/detail/CFunctions.h b/libs/lua/LuaBridge/detail/CFunctions.h
index 9f1712995a..fafad5d0a7 100644
--- a/libs/lua/LuaBridge/detail/CFunctions.h
+++ b/libs/lua/LuaBridge/detail/CFunctions.h
@@ -401,7 +401,6 @@ struct CFunc
     }
   };
 
-
   template <class T>
   struct PtrNullCheck
   {
@@ -430,6 +429,38 @@ struct CFunc
     }
   };
 
+  template <class T>
+  struct PtrEqualCheck
+  {
+    static int f (lua_State* L)
+    {
+      boost::shared_ptr<T> t0 = luabridge::Stack<boost::shared_ptr<T> >::get (L, 1);
+      boost::shared_ptr<T> t1 = luabridge::Stack<boost::shared_ptr<T> >::get (L, 2);
+      Stack <bool>::push (L, t0 == t1);
+      return 1;
+    }
+  };
+
+  template <class T>
+  struct WPtrEqualCheck
+  {
+    static int f (lua_State* L)
+    {
+      bool rv = false;
+      boost::weak_ptr<T> tw0 = luabridge::Stack<boost::weak_ptr<T> >::get (L, 1);
+      boost::weak_ptr<T> tw1 = luabridge::Stack<boost::weak_ptr<T> >::get (L, 2);
+      boost::shared_ptr<T> const t0 = tw0.lock();
+      boost::shared_ptr<T> const t1 = tw1.lock();
+      if (t0 && t1) {
+        T* const tt0 = t0.get();
+        T* const tt1 = t1.get();
+        rv = (tt0 == tt1);
+      }
+      Stack <bool>::push (L, rv);
+      return 1;
+    }
+  };
+
   template <class MemFnPtr, class T,
            class ReturnType = typename FuncTraits <MemFnPtr>::ReturnType>
   struct CallMemberWPtr
diff --git a/libs/lua/LuaBridge/detail/Namespace.h b/libs/lua/LuaBridge/detail/Namespace.h
index 07963f47db..7774b9f873 100644
--- a/libs/lua/LuaBridge/detail/Namespace.h
+++ b/libs/lua/LuaBridge/detail/Namespace.h
@@ -1298,6 +1298,21 @@ private:
       return *this;
     }
 
+    WSPtrClass <T>& addEqualCheck ()
+    {
+      PRINTDOC("Member Function", _name << "sameinstance", std::string("bool"), std::string("void (*)(" + type_name <T>() + ")"))
+      set_weak_class ();
+      assert (lua_istable (L, -1));
+      lua_pushcclosure (L, &CFunc::WPtrEqualCheck <T>::f, 0);
+      rawsetfield (L, -3, "isnil"); // class table
+
+      set_shared_class ();
+      assert (lua_istable (L, -1));
+      lua_pushcclosure (L, &CFunc::PtrEqualCheck <T>::f, 0);
+      rawsetfield (L, -3, "isnil"); // class table
+
+      return *this;
+    }
 
     Namespace endClass ()
     {
@@ -1652,7 +1667,8 @@ public:
   WSPtrClass <T> beginWSPtrClass (char const* name)
   {
     return WSPtrClass <T> (name, this)
-      .addNullCheck();
+      .addNullCheck()
+      .addEqualCheck();
   }
 
   //----------------------------------------------------------------------------
-- 
2.30.2