Fix leak in NasalObjectHolder

Thanks to Florent Rougon for spotting it.

simgear/nasal/code.c

@@ -787,6 +787,11 @@ void naGCRelease(int key)
   naHash_delete(globals->save_hash, naNum(key));
 }
 
+int naNumSaved()
+{
+  return naHash_size(globals->save_hash) + naVec_size(globals->save_hash);
+}
+
 void naClearSaved()
 {
     naContext c;

simgear/nasal/cppbind/NasalObjectHolder.hxx

@@ -139,10 +139,9 @@ namespace nasal
   template<class Base>
   ObjectHolder<Base>::ObjectHolder(naRef obj):
     _ref(obj),
-    _gc_key(0)
+    _gc_key(naIsNil(obj) ? 0 : naGCSave(obj))
   {
-    if( !naIsNil(obj) )
-      naGCSave(obj);
+
   }
 
   //----------------------------------------------------------------------------
@@ -159,7 +158,7 @@ namespace nasal
   SGSharedPtr<ObjectHolder<Base> >
   ObjectHolder<Base>::makeShared(naRef obj)
   {
-    return SGSharedPtr<ObjectHolder<Base> >( new ObjectHolder<SGReferenced>(obj) );
+    return SGSharedPtr<ObjectHolder<Base> >( new ObjectHolder<Base>(obj) );
   }
 
 } // namespace nasal

simgear/nasal/cppbind/test/nasal_gc_test.cxx

@@ -2,6 +2,9 @@
 #include <BoostTestTargetConfig.h>
 
 #include "TestContext.hxx"
+
+#include <simgear/nasal/cppbind/NasalObjectHolder.hxx>
+
 #include <iostream>
 #include <set>
 
@@ -91,3 +94,47 @@ BOOST_AUTO_TEST_CASE( ghost_gc )
 
   BOOST_REQUIRE(active_instances.empty());
 }
+
+//------------------------------------------------------------------------------
+BOOST_AUTO_TEST_CASE( object_holder_gc )
+{
+  TestContext c;
+  BOOST_REQUIRE_EQUAL(naNumSaved(), 0);
+  BOOST_REQUIRE(active_instances.empty());
+
+  //-----------------------------------------------
+  // Put some ghosts in ObjectHolder and check if
+  // they are saved from gc
+
+  naRef g1 = createTestGhost(c, 1),
+        g2 = createTestGhost(c, 2);
+
+  nasal::ObjectHolder<> h1(g1);
+  BOOST_CHECK_EQUAL(naNumSaved(), 1);
+  BOOST_CHECK(naIsGhost(h1.get_naRef()));
+
+  nasal::ObjectHolder<> h2(g2);
+  BOOST_CHECK_EQUAL(naNumSaved(), 2);
+  BOOST_CHECK(naIsGhost(h2.get_naRef()));
+
+  c.runGC();
+
+  BOOST_CHECK_EQUAL(active_instances.size(), 2);
+  BOOST_CHECK_EQUAL(naNumSaved(), 2);
+
+  h1.reset(naNum(1));
+  h2.reset(naNum(2));
+  BOOST_CHECK_EQUAL(naNumSaved(), 2);
+
+  //-----------------------------------------------
+  // Check that the saved objects are released
+
+  h1.reset();
+  BOOST_CHECK_EQUAL(naNumSaved(), 1);
+
+  h2.reset();
+  BOOST_CHECK_EQUAL(naNumSaved(), 0);
+
+  c.runGC();
+  BOOST_CHECK_EQUAL(active_instances.size(), 0);
+}

simgear/nasal/nasal.h

@@ -58,6 +58,10 @@ int naGCSave(naRef obj);
 // by the garbage collector.
 void naGCRelease(int key);
 
+// Get the number of currently saved and not yet again released objects
+// (saved by naSave or naGCSave)
+int naNumSaved();
+
 // Drop all saved references
 void naClearSaved();