[vala] codegen: Fix freeing of GLists with null elements

[Jürg Billeter <juergbi src gnome org>]

commit fbd62577e03bd518aa1bed6dae18be43700108e1
Author: Jürg Billeter <j bitron ch>
Date:   Thu Oct 14 15:38:54 2010 +0200

    codegen: Fix freeing of GLists with null elements
    
    Fixes bug 585341.

 codegen/valaccodebasemodule.vala |   23 +++++++++++++++++++++++
 1 files changed, 23 insertions(+), 0 deletions(-)
---
diff --git a/codegen/valaccodebasemodule.vala b/codegen/valaccodebasemodule.vala
index 209aaa9..2517c9a 100644
--- a/codegen/valaccodebasemodule.vala
+++ b/codegen/valaccodebasemodule.vala
@@ -2652,6 +2652,29 @@ public class Vala.CCodeBaseModule : CodeGenerator {
 				elements_require_free = requires_destroy (type_arg);
 				if (elements_require_free) {
 					element_destroy_func_expression = get_destroy_func_expression (type_arg);
+
+					if (element_destroy_func_expression is CCodeIdentifier) {
+						var freeid = (CCodeIdentifier) element_destroy_func_expression;
+						string free0_func = "_%s0_".printf (freeid.name);
+
+						if (add_wrapper (free0_func)) {
+							var function = new CCodeFunction (free0_func, "void");
+							function.modifiers = CCodeModifiers.STATIC;
+
+							function.add_parameter (new CCodeFormalParameter ("var", "gpointer"));
+
+							push_function (function);
+
+							ccode.add_expression (get_unref_expression (new CCodeIdentifier ("var"), type_arg, null, true));
+
+							pop_function ();
+
+							cfile.add_function_declaration (function);
+							cfile.add_function (function);
+						}
+
+						element_destroy_func_expression = new CCodeIdentifier (free0_func);
+					}
 				}
 			}