cell 0.1.8

// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Modified work Copyright 2018-2019 Daniel Mueller (deso@posteo.net).
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use std::cell::Cell;
use std::mem::drop;
use std::slice::Iter;

use cell::Ref;
use cell::RefCell;
use cell::RefMut;
use cell::RefVal;


#[test]
fn ref_and_refmut_have_sensible_show() {
    let refcell = RefCell::new("foo");

    let refcell_refmut = refcell.borrow_mut();
    assert!(format!("{:?}", refcell_refmut).contains("foo"));
    drop(refcell_refmut);

    let refcell_ref = refcell.borrow();
    assert!(format!("{:?}", refcell_ref).contains("foo"));
    drop(refcell_ref);
}

#[test]
fn double_imm_borrow() {
    let x = RefCell::new(0);
    let _b1 = x.borrow();
    x.borrow();
}

#[test]
fn no_mut_then_imm_borrow() {
    let x = RefCell::new(0);
    let _b1 = x.borrow_mut();
    assert!(x.try_borrow().is_err());
}

#[test]
fn no_imm_then_borrow_mut() {
    let x = RefCell::new(0);
    let _b1 = x.borrow();
    assert!(x.try_borrow_mut().is_err());
}

#[test]
fn no_double_borrow_mut() {
    let x = RefCell::new(0);
    assert!(x.try_borrow().is_ok());
    let _b1 = x.borrow_mut();
    assert!(x.try_borrow().is_err());
}

#[test]
fn imm_release_borrow_mut() {
    let x = RefCell::new(0);
    {
        let _b1 = x.borrow();
    }
    x.borrow_mut();
}

#[test]
fn mut_release_borrow_mut() {
    let x = RefCell::new(0);
    {
        let _b1 = x.borrow_mut();
    }
    x.borrow();
}

#[test]
fn double_borrow_single_release_no_borrow_mut() {
    let x = RefCell::new(0);
    let _b1 = x.borrow();
    {
        let _b2 = x.borrow();
    }
    assert!(x.try_borrow().is_ok());
    assert!(x.try_borrow_mut().is_err());
}

#[test]
#[should_panic]
fn discard_doesnt_unborrow() {
    let x = RefCell::new(0);
    let _b = x.borrow();
    let _ = _b;
    let _b = x.borrow_mut();
}

#[test]
fn ref_clone_updates_flag() {
    let x = RefCell::new(0);
    {
        let b1 = x.borrow();
        assert!(x.try_borrow().is_ok());
        assert!(x.try_borrow_mut().is_err());
        {
            let _b2 = Ref::clone(&b1);
            assert!(x.try_borrow().is_ok());
            assert!(x.try_borrow_mut().is_err());
        }
        assert!(x.try_borrow().is_ok());
        assert!(x.try_borrow_mut().is_err());
    }
    assert!(x.try_borrow().is_ok());
    assert!(x.try_borrow_mut().is_ok());
}

#[test]
fn ref_map_does_not_update_flag() {
    let x = RefCell::new(Some(5));
    {
        let b1: Ref<Option<u32>> = x.borrow();
        assert!(x.try_borrow().is_ok());
        assert!(x.try_borrow_mut().is_err());
        {
            let b2: Ref<u32> = Ref::map(b1, |o| o.as_ref().unwrap());
            assert_eq!(*b2, 5);
            assert!(x.try_borrow().is_ok());
            assert!(x.try_borrow_mut().is_err());
        }
        assert!(x.try_borrow().is_ok());
        assert!(x.try_borrow_mut().is_ok());
    }
    assert!(x.try_borrow().is_ok());
    assert!(x.try_borrow_mut().is_ok());
}

#[test]
fn ref_map_split_updates_flag() {
    let x = RefCell::new([1, 2]);
    {
        let b1 = x.borrow();
        assert!(x.try_borrow().is_ok());
        assert!(x.try_borrow_mut().is_err());
        {
            let (_b2, _b3) = Ref::map_split(b1, |slc| slc.split_at(1));
            assert!(x.try_borrow().is_ok());
            assert!(x.try_borrow_mut().is_err());
        }
        assert!(x.try_borrow().is_ok());
        assert!(x.try_borrow_mut().is_ok());
    }
    assert!(x.try_borrow().is_ok());
    assert!(x.try_borrow_mut().is_ok());

    {
        let b1 = x.borrow_mut();
        assert!(x.try_borrow().is_err());
        assert!(x.try_borrow_mut().is_err());
        {
            let (_b2, _b3) = RefMut::map_split(b1, |slc| slc.split_at_mut(1));
            assert!(x.try_borrow().is_err());
            assert!(x.try_borrow_mut().is_err());
            drop(_b2);
            assert!(x.try_borrow().is_err());
            assert!(x.try_borrow_mut().is_err());
        }
        assert!(x.try_borrow().is_ok());
        assert!(x.try_borrow_mut().is_ok());
    }
    assert!(x.try_borrow().is_ok());
    assert!(x.try_borrow_mut().is_ok());
}

#[test]
fn ref_map_split() {
    let x = RefCell::new([1, 2]);
    let (b1, b2) = Ref::map_split(x.borrow(), |slc| slc.split_at(1));
    assert_eq!(*b1, [1]);
    assert_eq!(*b2, [2]);
}

#[test]
fn ref_mut_map_split() {
    let x = RefCell::new([1, 2]);
    {
        let (mut b1, mut b2) = RefMut::map_split(x.borrow_mut(), |slc| slc.split_at_mut(1));
        assert_eq!(*b1, [1]);
        assert_eq!(*b2, [2]);
        b1[0] = 2;
        b2[0] = 1;
    }
    assert_eq!(*x.borrow(), [2, 1]);
}

#[test]
fn ref_map_accessor() {
    struct X(RefCell<(u32, char)>);
    impl X {
        fn accessor(&self) -> Ref<u32> {
            Ref::map(self.0.borrow(), |tuple| &tuple.0)
        }
    }
    let x = X(RefCell::new((7, 'z')));
    let d: Ref<u32> = x.accessor();
    assert_eq!(*d, 7);
}

#[test]
fn ref_mut_map_accessor() {
    struct X(RefCell<(u32, char)>);
    impl X {
        fn accessor(&self) -> RefMut<u32> {
            RefMut::map(self.0.borrow_mut(), |tuple| &mut tuple.0)
        }
    }
    let x = X(RefCell::new((7, 'z')));
    {
        let mut d: RefMut<u32> = x.accessor();
        assert_eq!(*d, 7);
        *d += 1;
    }
    assert_eq!(*x.0.borrow(), (8, 'z'));
}

#[test]
fn as_ptr() {
    let c1: Cell<usize> = Cell::new(0);
    c1.set(1);
    assert_eq!(1, unsafe { *c1.as_ptr() });

    let c2: Cell<usize> = Cell::new(0);
    unsafe { *c2.as_ptr() = 1; }
    assert_eq!(1, c2.get());

    let r1: RefCell<usize> = RefCell::new(0);
    *r1.borrow_mut() = 1;
    assert_eq!(1, unsafe { *r1.as_ptr() });

    let r2: RefCell<usize> = RefCell::new(0);
    unsafe { *r2.as_ptr() = 1; }
    assert_eq!(1, *r2.borrow());
}

#[test]
fn cell_default() {
    let cell: Cell<u32> = Default::default();
    assert_eq!(0, cell.get());
}

#[test]
fn cell_set() {
    let cell = Cell::new(10);
    cell.set(20);
    assert_eq!(20, cell.get());

    let cell = Cell::new("Hello".to_owned());
    cell.set("World".to_owned());
    assert_eq!("World".to_owned(), cell.into_inner());
}

#[test]
fn cell_replace() {
    let cell = Cell::new(10);
    assert_eq!(10, cell.replace(20));
    assert_eq!(20, cell.get());

    let cell = Cell::new("Hello".to_owned());
    assert_eq!("Hello".to_owned(), cell.replace("World".to_owned()));
    assert_eq!("World".to_owned(), cell.into_inner());
}

#[test]
fn cell_into_inner() {
    let cell = Cell::new(10);
    assert_eq!(10, cell.into_inner());

    let cell = Cell::new("Hello world".to_owned());
    assert_eq!("Hello world".to_owned(), cell.into_inner());
}

#[test]
fn refcell_default() {
    let cell: RefCell<u64> = Default::default();
    assert_eq!(0, *cell.borrow());
}

#[test]
fn refcell_unsized() {
    let cell: &RefCell<[i32]> = &RefCell::new([1, 2, 3]);
    {
        let b = &mut *cell.borrow_mut();
        b[0] = 4;
        b[2] = 5;
    }
    let comp: &mut [i32] = &mut [4, 2, 5];
    assert_eq!(&*cell.borrow(), comp);
}

#[test]
#[should_panic]
fn refcell_swap_borrows() {
    let x = RefCell::new(0);
    let _b = x.borrow();
    let y = RefCell::new(1);
    x.swap(&y);
}

#[test]
#[should_panic]
fn refcell_replace_borrows() {
    let x = RefCell::new(0);
    let _b = x.borrow();
    x.replace(1);
}


#[derive(Clone)]
struct RefStrings(RefCell<Vec<String>>);

impl RefStrings {
    fn iter<'t, 's: 't>(&'s self) -> RefVal<'t, Iter<String>> {
        Ref::map_val(self.0.borrow(), |x| x.iter())
    }
}


#[test]
fn refval_with_iterator() {
    let strings = vec![
        "one".to_string(),
        "two".to_string(),
        "three".to_string(),
    ];

    let ref_strings = RefStrings(RefCell::new(strings));
    let mut it = ref_strings.iter().clone().rev().skip(1);
    assert_eq!(it.next().unwrap(), "two");
    assert_eq!(it.next().unwrap(), "one");
    assert!(it.next().is_none());
}

#[test]
fn refval_clone() {
    let strings = vec![
        "four".to_string(),
        "five".to_string(),
        "six".to_string(),
    ];

    let ref_strings1 = RefStrings(RefCell::new(strings));
    let mut it1 = ref_strings1.iter();
    assert_eq!(it1.next().unwrap(), "four");

    let ref_strings2 = ref_strings1.clone();
    let mut it2 = ref_strings2.iter();
    assert_eq!(it2.next().unwrap(), "four");
}


#[derive(Debug)]
struct Val {
  val: u64,
}

#[test]
fn refval_debug() {
    let val = Val{val: 42};
    let ref_cell = RefCell::new(val);
    let ref_val = Ref::map_val(ref_cell.borrow(), |x| x);

    assert_eq!(format!("{:?}", ref_val), "Val { val: 42 }")
}

#[test]
fn refval_map() {
    let ref_strings = RefCell::new(vec![
        "ten".to_owned(),
        "eleven".to_owned(),
        "twelve".to_owned(),
    ]);

    // `RefVal` containing an iterator over `ref_strings` strings
    let it_1 = Ref::map_val(RefCell::borrow(&ref_strings), |v| v.iter().map(|s| s.as_str()));
    // Map `RefVal` to another `RefVal`: collect iterator into a vector.
    // Note that the new `Vec` contains references to original `String`
    // objects.
    let refs_1 = RefVal::map(it_1, |it| it.collect::<Vec<&str>>());
    drop(refs_1);

    // Assert refcount == 0
    ref_strings.borrow_mut();
}

#[test]
fn refvalmut() {
    let ref_strings = RefCell::new(vec![
        "one".to_owned(),
        "two".to_owned(),
        "three".to_owned(),
    ]);

    // `RefValMut` containing a mutable iterator over `ref_strings` strings
    let mut it_1 = RefMut::map_val(RefCell::borrow_mut(&ref_strings), |v| v.iter_mut());
    for s in &mut it_1.by_ref() {
        s.make_ascii_uppercase();
    }
    drop(it_1);

    let strings = ref_strings.borrow();
    assert_eq!(vec![
        "ONE".to_owned(),
        "TWO".to_owned(),
        "THREE".to_owned(),
    ], *strings);
}