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luaur_vm/functions/
lua_l_getmetafield.rs

1use crate::functions::lua_getmetatable::lua_getmetatable;
2use crate::functions::lua_pushstring::lua_pushstring;
3use crate::functions::lua_rawget::lua_rawget;
4use crate::functions::lua_remove::lua_remove;
5use crate::macros::lua_pop::lua_pop;
6use crate::type_aliases::lua_state::lua_State;
7use core::ffi::{c_char, c_int};
8
9#[no_mangle]
10pub unsafe fn lua_l_getmetafield(L: *mut lua_State, obj: c_int, event: *const c_char) -> c_int {
11    if lua_getmetatable(L, obj) == 0 {
12        return 0; // no metatable
13    }
14
15    lua_pushstring(L, event);
16    lua_rawget(L, -2);
17
18    let is_nil = crate::functions::lua_type::lua_type(L, -1)
19        == (crate::enums::lua_type::lua_Type::LUA_TNIL as i32);
20
21    if is_nil {
22        lua_pop(L, 2); // remove metatable and metafield
23        return 0;
24    } else {
25        lua_remove(L, -2); // remove only metatable
26        return 1;
27    }
28}