gistfile1.txt

use std::collections::HashMap;
use std::collections::hash_map::Entry;
use std::cell::RefCell;
use std::rc::Rc;

#[derive(Debug)]
struct Bar {
    x: u32,
}

struct Foo {
    view_a: HashMap<u32, Rc<RefCell<Bar>>>,
    view_b: HashMap<u32, Rc<RefCell<Bar>>>,
}

fn init_hash(foo: &mut Foo) {
    let bar = Bar { x: 16 };
    let ref_bar = RefCell::new(bar);
    let rc_bar = Rc::new(ref_bar);

    foo.view_a.insert(8, rc_bar.clone());
    foo.view_b.insert(16, rc_bar.clone());

}


fn main() {

    let mut foo = Foo {
        view_a: HashMap::new(),
        view_b: HashMap::new(),
    };

    init_hash(&mut foo);


    {
        if let Entry::Occupied(mut res) = foo.view_a.entry(8) {
            let mut a: Rc<RefCell<Bar>> = *res.get_mut();
            println!("View A: {:?}", a);
            let b = a.get_mut();
            //let b = (*a).try_unwrap();
            println!("View A.get_mut(): {:?}", b);
            //b.x = 12;

        }
        if let Entry::Occupied(mut res) = foo.view_b.entry(16) {
            let a = res.get_mut();
            println!("View B: {:?}", a);

        }
    }
}