添加xlua.release，用于主动解除lua对c#某对象的引用

Assets/XLua/Src/ObjectTranslator.cs

@@ -569,6 +569,9 @@ namespace XLua
             LuaAPI.xlua_pushasciistring(L, "tofunction");
             LuaAPI.lua_pushstdcallcfunction(L, StaticLuaCallbacks.ToFunction);
             LuaAPI.lua_rawset(L, -3);
+            LuaAPI.xlua_pushasciistring(L, "release");
+            LuaAPI.lua_pushstdcallcfunction(L, StaticLuaCallbacks.ReleaseCsObject);
+            LuaAPI.lua_rawset(L, -3);
             LuaAPI.lua_pop(L, 1);
 
             LuaAPI.lua_createtable(L, 1, 4); // 4 for __gc, __tostring, __index, __newindex
@@ -1217,6 +1220,15 @@ namespace XLua
             return getCsObj(L, index, LuaAPI.xlua_tocsobj_fast(L,index));
         }
 
+        internal void ReleaseCSObj(RealStatePtr L, int index)
+        {
+            int udata = LuaAPI.xlua_tocsobj_safe(L, index);
+            if (udata != -1)
+            {
+                objects.Replace(udata, null);
+            }
+        }
+
         List<LuaCSFunction> fix_cs_functions = new List<LuaCSFunction>();
 
         internal LuaCSFunction GetFixCSFunction(int index)

Assets/XLua/Src/StaticLuaCallbacks.cs

@@ -29,7 +29,7 @@ namespace XLua
         internal LuaCSFunction StaticCSFunctionWraper, FixCSFunctionWraper;
 
         internal LuaCSFunction DelegateCtor;
-        
+
         public StaticLuaCallbacks()
         {
             GcMeta = new LuaCSFunction(StaticLuaCallbacks.LuaGC);
@@ -94,7 +94,7 @@ namespace XLua
                 LuaCSFunction func = (LuaCSFunction)translator.FastGetCSObj(L, LuaAPI.xlua_upvalueindex(1));
                 return func(L);
             }
-            catch(Exception e)
+            catch (Exception e)
             {
                 return LuaAPI.luaL_error(L, "c# exception in StaticCSFunction:" + e);
             }
@@ -1079,5 +1079,20 @@ namespace XLua
                 return LuaAPI.luaL_error(L, "c# exception in ToFunction: " + e);
             }
         }
+
+        [MonoPInvokeCallback(typeof(LuaCSFunction))]
+        public static int ReleaseCsObject(RealStatePtr L)
+        {
+            try
+            {
+                ObjectTranslator translator = ObjectTranslatorPool.Instance.Find(L);
+                translator.ReleaseCSObj(L, 1);
+                return 0;
+            }
+            catch (Exception e)
+            {
+                return LuaAPI.luaL_error(L, "c# exception in ReleaseCsObject: " + e);
+            }
+        }
     }
 }
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