/*
 *   Copyright (c) 2022 R3BL LLC
 *   All rights reserved.
 *
 *   Licensed under the Apache License, Version 2.0 (the "License");
 *   you may not use this file except in compliance with the License.
 *   You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 *   Unless required by applicable law or agreed to in writing, software
 *   distributed under the License is distributed on an "AS IS" BASIS,
 *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *   See the License for the specific language governing permissions and
 *   limitations under the License.
 */

//! New in Rust v 1.60.0: Arc cyclic references.
//! https://doc.rust-lang.org/stable/std/sync/struct.Arc.html#method.new_cyclic

use std::sync::{Arc, RwLock, Weak};

#[test]
fn test_new() {
    struct Gadget {
        pub weak_me: Weak<RwLock<Gadget>>,
        pub data: String,
    }

    impl Gadget {
        /// Construct a reference counted Gadget.
        fn new() -> Arc<RwLock<Self>> {
            Arc::new_cyclic(|weak_me_ref| {
                let weak_me_clone = weak_me_ref.clone();
                RwLock::new(Gadget {
                    weak_me: weak_me_clone,
                    data: Default::default(),
                })
            })
        }

        /// Return a reference counted pointer to Self.
        pub fn clone_arc(&self) -> Arc<RwLock<Self>> { self.weak_me.upgrade().unwrap() }

        pub fn set_data(&mut self, arg: &str) { self.data = String::from(arg); }

        pub fn get_data(&self) -> String { self.data.clone() }
    }

    let g_arc: Arc<RwLock<Gadget>> = Gadget::new();

    g_arc.write().unwrap().set_data("foo");
    assert_eq!(g_arc.read().unwrap().get_data(), "foo");

    let g_arc_clone: Arc<RwLock<Gadget>> = g_arc.read().unwrap().clone_arc();
    g_arc_clone.write().unwrap().set_data("dummy");
    assert_eq!(g_arc_clone.read().unwrap().get_data(), "dummy");
}