resman/
ref.rs

1use std::{fmt, marker::PhantomData, ops::Deref};
2
3use crate::Resource;
4
5/// Reference to a resource.
6#[derive(Clone)]
7pub struct Ref<'a, R: 'a> {
8    inner: rt_map::Ref<'a, Box<dyn Resource>>,
9    phantom: PhantomData<&'a R>,
10}
11
12impl<'a, R> Ref<'a, R> {
13    pub fn new(inner: rt_map::Ref<'a, Box<dyn Resource>>) -> Self {
14        Self {
15            inner,
16            phantom: PhantomData,
17        }
18    }
19}
20
21impl<R> Deref for Ref<'_, R>
22where
23    R: Resource,
24{
25    type Target = R;
26
27    fn deref(&self) -> &R {
28        (*self.inner)
29            .downcast_ref::<R>()
30            .unwrap_or_else(|| panic!("Failed to downcast to {}", std::any::type_name::<R>()))
31    }
32}
33
34impl<'a, R> fmt::Debug for Ref<'a, R>
35where
36    R: Resource + fmt::Debug + 'a,
37{
38    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
39        let inner: &R = self;
40        f.debug_struct("Ref").field("inner", inner).finish()
41    }
42}
43
44impl<'a, R> PartialEq for Ref<'a, R>
45where
46    R: Resource + PartialEq + 'a,
47{
48    fn eq(&self, other: &Self) -> bool {
49        let r_self: &R = self;
50        let r_other: &R = other;
51        r_self == r_other
52    }
53}
54
55#[cfg(test)]
56mod tests {
57    use std::fmt::{self, Write};
58
59    use rt_map::Cell;
60
61    use crate::Resource;
62
63    use super::Ref;
64
65    #[test]
66    fn debug_includes_inner_field() -> fmt::Result {
67        let value: Box<dyn Resource> = Box::new(A(1));
68        let cell = Cell::new(value);
69        let r#ref = Ref::<A>::new(rt_map::Ref::new(cell.borrow()));
70
71        let mut debug_string = String::with_capacity(64);
72        write!(&mut debug_string, "{:?}", r#ref)?;
73        assert_eq!("Ref { inner: A(1) }", debug_string.as_str());
74
75        Ok(())
76    }
77
78    #[test]
79    fn partial_eq_compares_value() -> fmt::Result {
80        let value_0: Box<dyn Resource> = Box::new(A(1));
81        let cell_0 = Cell::new(value_0);
82        let ref_0 = Ref::<A>::new(rt_map::Ref::new(cell_0.borrow()));
83
84        let value_1: Box<dyn Resource> = Box::new(A(1));
85        let cell_1 = Cell::new(value_1);
86        let ref_1 = Ref::<A>::new(rt_map::Ref::new(cell_1.borrow()));
87
88        assert_eq!(ref_1, ref_0);
89        assert_eq!(Ref::<A>::new(rt_map::Ref::new(cell_0.borrow())), ref_0);
90
91        Ok(())
92    }
93
94    #[derive(Debug, Clone, PartialEq)]
95    struct A(usize);
96}
resman/ref.rs

resman/
ref.rs
