use std::any::{Any, TypeId};
use std::fmt;
use fxhash::FxHashMap;
#[derive(Default)]
pub struct Extensions {
map: FxHashMap<TypeId, Box<dyn Any>>,
}
impl Extensions {
#[inline]
pub fn new() -> Extensions {
Extensions {
map: FxHashMap::default(),
}
}
pub fn insert<T: 'static>(&mut self, val: T) {
self.map.insert(TypeId::of::<T>(), Box::new(val));
}
pub fn contains<T: 'static>(&self) -> bool {
self.map.get(&TypeId::of::<T>()).is_some()
}
pub fn get<T: 'static>(&self) -> Option<&T> {
self.map
.get(&TypeId::of::<T>())
.and_then(|boxed| (&**boxed as &(dyn Any + 'static)).downcast_ref())
}
pub fn get_mut<T: 'static>(&mut self) -> Option<&mut T> {
self.map
.get_mut(&TypeId::of::<T>())
.and_then(|boxed| (&mut **boxed as &mut (dyn Any + 'static)).downcast_mut())
}
pub fn remove<T: 'static>(&mut self) -> Option<T> {
self.map.remove(&TypeId::of::<T>()).and_then(|boxed| {
(boxed as Box<dyn Any + 'static>)
.downcast()
.ok()
.map(|boxed| *boxed)
})
}
#[inline]
pub fn clear(&mut self) {
self.map.clear();
}
}
impl fmt::Debug for Extensions {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("Extensions").finish()
}
}
#[test]
fn test_extensions() {
#[derive(Debug, PartialEq)]
struct MyType(i32);
let mut extensions = Extensions::new();
extensions.insert(5i32);
extensions.insert(MyType(10));
assert_eq!(extensions.get(), Some(&5i32));
assert_eq!(extensions.get_mut(), Some(&mut 5i32));
assert_eq!(extensions.remove::<i32>(), Some(5i32));
assert!(extensions.get::<i32>().is_none());
assert_eq!(extensions.get::<bool>(), None);
assert_eq!(extensions.get(), Some(&MyType(10)));
}