mlua-rs-mlua/src/tests/userdata.rs

use std::sync::Arc;

use {ExternalError, Function, Lua, MetaMethod, String, UserData, UserDataMethods};

#[test]
fn test_user_data() {
    struct UserData1(i64);
    struct UserData2(Box<i64>);

    impl UserData for UserData1 {};
    impl UserData for UserData2 {};

    let lua = Lua::new();

    let userdata1 = lua.create_userdata(UserData1(1)).unwrap();
    let userdata2 = lua.create_userdata(UserData2(Box::new(2))).unwrap();

    assert!(userdata1.is::<UserData1>());
    assert!(!userdata1.is::<UserData2>());
    assert!(userdata2.is::<UserData2>());
    assert!(!userdata2.is::<UserData1>());

    assert_eq!(userdata1.borrow::<UserData1>().unwrap().0, 1);
    assert_eq!(*userdata2.borrow::<UserData2>().unwrap().0, 2);
}

#[test]
fn test_methods() {
    struct MyUserData(i64);

    impl UserData for MyUserData {
        fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
            methods.add_method("get_value", |_, data, ()| Ok(data.0));
            methods.add_method_mut("set_value", |_, data, args| {
                data.0 = args;
                Ok(())
            });
        }
    }

    let lua = Lua::new();
    let globals = lua.globals();
    let userdata = lua.create_userdata(MyUserData(42)).unwrap();
    globals.set("userdata", userdata.clone()).unwrap();
    lua.exec::<()>(
        r#"
            function get_it()
                return userdata:get_value()
            end

            function set_it(i)
                return userdata:set_value(i)
            end
        "#,
        None,
    ).unwrap();
    let get = globals.get::<_, Function>("get_it").unwrap();
    let set = globals.get::<_, Function>("set_it").unwrap();
    assert_eq!(get.call::<_, i64>(()).unwrap(), 42);
    userdata.borrow_mut::<MyUserData>().unwrap().0 = 64;
    assert_eq!(get.call::<_, i64>(()).unwrap(), 64);
    set.call::<_, ()>(100).unwrap();
    assert_eq!(get.call::<_, i64>(()).unwrap(), 100);
}

#[test]
fn test_metamethods() {
    #[derive(Copy, Clone)]
    struct MyUserData(i64);

    impl UserData for MyUserData {
        fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
            methods.add_method("get", |_, data, ()| Ok(data.0));
            methods.add_meta_function(
                MetaMethod::Add,
                |_, (lhs, rhs): (MyUserData, MyUserData)| Ok(MyUserData(lhs.0 + rhs.0)),
            );
            methods.add_meta_function(
                MetaMethod::Sub,
                |_, (lhs, rhs): (MyUserData, MyUserData)| Ok(MyUserData(lhs.0 - rhs.0)),
            );
            methods.add_meta_method(MetaMethod::Index, |_, data, index: String| {
                if index.to_str()? == "inner" {
                    Ok(data.0)
                } else {
                    Err(format_err!("no such custom index").to_lua_err())
                }
            });
        }
    }

    let lua = Lua::new();
    let globals = lua.globals();
    globals.set("userdata1", MyUserData(7)).unwrap();
    globals.set("userdata2", MyUserData(3)).unwrap();
    assert_eq!(
        lua.eval::<MyUserData>("userdata1 + userdata2", None)
            .unwrap()
            .0,
        10
    );
    assert_eq!(
        lua.eval::<MyUserData>("userdata1 - userdata2", None)
            .unwrap()
            .0,
        4
    );
    assert_eq!(lua.eval::<i64>("userdata1:get()", None).unwrap(), 7);
    assert_eq!(lua.eval::<i64>("userdata2.inner", None).unwrap(), 3);
    assert!(lua.eval::<()>("userdata2.nonexist_field", None).is_err());
}

#[test]
fn test_gc_userdata() {
    struct MyUserdata {
        id: u8,
    }

    impl UserData for MyUserdata {
        fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
            methods.add_method("access", |_, this, ()| {
                assert!(this.id == 123);
                Ok(())
            });
        }
    }

    let lua = Lua::new();
    {
        let globals = lua.globals();
        globals.set("userdata", MyUserdata { id: 123 }).unwrap();
    }

    assert!(
        lua.eval::<()>(
            r#"
                local tbl = setmetatable({
                    userdata = userdata
                }, { __gc = function(self)
                    -- resurrect userdata
                    hatch = self.userdata
                end })

                tbl = nil
                userdata = nil  -- make table and userdata collectable
                collectgarbage("collect")
                hatch:access()
            "#,
            None
        ).is_err()
    );
}

#[test]
fn detroys_userdata() {
    struct MyUserdata(Arc<()>);

    impl UserData for MyUserdata {}

    let rc = Arc::new(());

    let lua = Lua::new();
    {
        let globals = lua.globals();
        globals.set("userdata", MyUserdata(rc.clone())).unwrap();
    }

    assert_eq!(Arc::strong_count(&rc), 2);
    drop(lua); // should destroy all objects
    assert_eq!(Arc::strong_count(&rc), 1);
}

#[test]
fn user_value() {
    let lua = Lua::new();

    struct MyUserData;
    impl UserData for MyUserData {}

    let ud = lua.create_userdata(MyUserData).unwrap();
    ud.set_user_value("hello").unwrap();
    assert_eq!(ud.get_user_value::<String>().unwrap(), "hello");
    assert!(ud.get_user_value::<u32>().is_err());
}