在luabind :: object中存储带父类的lua类 [英] Storing a lua class with parent in luabind::object

问题描述

使用 C ++ ， lua 5.1 ， luabind 0.7-0.81

创建一个带父类的lua类，并将其存储在luabind :: object中。

Trying to create a lua class with parent and store it in a luabind::object.

Lua

class 'TestClassParent'
function TestClassParent:__init()
    print('parent init\n')
end
function TestClassParent:__finalize()
    print('parent finalize\n')
end

class 'TestClass' (TestClassParent)
function TestClass:__init()
    print('init\n')
    TestClassParent.__init(self)
end
function TestClass:__finalize()
    print('finalize\n')
end

C ++

{
    luabind::object obj = luabind::call_function<luabind::object>(lua_state, "TestClass");
}
printf("before GC\n");
lua_gc(lua, LUA_GCCOLLECT, 0);
printf("after GC\n");

输出：

初始化

父级初始化

在GC之前

在GC之后

Output:
init
parent init
before GC
after GC

结果： destroy，'TestClass'实例在垃圾收集循环后仍然存在（__finalize方法未被调用，内存不被释放）。

Moresome 如果我使用没有父类的类，垃圾被正确收集。

Result: After obj is destroyed, 'TestClass' instance is still alive after garbage collection cycle (__finalize method is not called and memory is not freed). It's destroying only on program exit.
Moresome if I use class without parent, garbage is collected correctly.

如果我尝试使用采用政策（获取已创建对象的所有权）

If I try to use adopt policy (to take ownership of created object)

luabind::object obj = luabind::call_function<luabind::object>(lua_state, "TestClass")[luabind::adopt(luabind::result)];

我得到：

• 在 luabind 0.7 中显示的结果与未采用政策时相同


• 要使用unregistrerd类型

• in luabind 0.7 - same result as without adopt policy
• in luabind 0.81 - crash with message "you are trying to use an unregistrerd type"

如何正确在C ++中创建lua对象

推荐答案

这是一个在0.8.1中的已知错误;对最后构造的对象的引用留在超级函数上值中。它已在0.9-rc1中修复：

This is a known bug in 0.8.1; a reference to the last constructed object is left in the "super" function upvalue. It has been fixed in 0.9-rc1:

http：// github.com/luabind/luabind/commit/2c99f0475afea7c282c2e432499fd22aa17744e3

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