pub struct MetaTable<T: ?Sized> { /* private fields */ }
Expand description
The MetaTable
which allows to store object-safe trait implementations for
resources.
For example, you have a trait Foo
that is implemented by several
resources. You can register all the implementors using
MetaTable::register
. Later on, you can iterate over all resources that
implement Foo
without knowing their specific type.
Examples
use shred::{CastFrom, MetaTable, World};
trait Object {
fn method1(&self) -> i32;
fn method2(&mut self, x: i32);
}
unsafe impl<T> CastFrom<T> for dyn Object
where
T: Object + 'static,
{
fn cast(t: *mut T) -> *mut Self {
t
}
}
struct ImplementorA(i32);
impl Object for ImplementorA {
fn method1(&self) -> i32 {
self.0
}
fn method2(&mut self, x: i32) {
self.0 += x;
}
}
struct ImplementorB(i32);
impl Object for ImplementorB {
fn method1(&self) -> i32 {
self.0
}
fn method2(&mut self, x: i32) {
self.0 *= x;
}
}
let mut world = World::empty();
world.insert(ImplementorA(3));
world.insert(ImplementorB(1));
let mut table = MetaTable::<dyn Object>::new();
table.register::<ImplementorA>();
table.register::<ImplementorB>();
{
let mut iter = table.iter(&mut world);
assert_eq!(iter.next().unwrap().method1(), 3);
assert_eq!(iter.next().unwrap().method1(), 1);
}
Implementations§
source§impl<T: ?Sized> MetaTable<T>
impl<T: ?Sized> MetaTable<T>
sourcepub fn get<'a>(&self, res: &'a dyn Resource) -> Option<&'a T>
pub fn get<'a>(&self, res: &'a dyn Resource) -> Option<&'a T>
Tries to convert world
to a trait object of type &T
.
If world
doesn’t have an implementation for T
(or it wasn’t
registered), this will return None
.
sourcepub fn get_mut<'a>(&self, res: &'a mut dyn Resource) -> Option<&'a mut T>
pub fn get_mut<'a>(&self, res: &'a mut dyn Resource) -> Option<&'a mut T>
Tries to convert world
to a trait object of type &mut T
.
If world
doesn’t have an implementation for T
(or it wasn’t
registered), this will return None
.
sourcepub fn iter<'a>(&'a self, res: &'a World) -> MetaIter<'a, T> ⓘ
pub fn iter<'a>(&'a self, res: &'a World) -> MetaIter<'a, T> ⓘ
Iterates all resources that implement T
and were registered.
sourcepub fn iter_mut<'a>(&'a self, res: &'a World) -> MetaIterMut<'a, T> ⓘ
pub fn iter_mut<'a>(&'a self, res: &'a World) -> MetaIterMut<'a, T> ⓘ
Iterates all resources that implement T
and were registered mutably.