use std::any::{Any, TypeId};
use std::collections::HashMap;
use std::fmt;
#[derive(Default)]
pub struct Extensions {
map: HashMap<TypeId, Box<dyn Any + Send + Sync>>,
}
impl Extensions {
pub fn new() -> Self {
Self {
map: HashMap::default(),
}
}
pub fn with<T: Send + Sync + 'static>(mut self, val: T) -> Self {
self.insert(val);
self
}
pub fn append(&mut self, other: &mut Self) {
self.map.extend(other.map.drain())
}
pub fn insert<T: Send + Sync + 'static>(&mut self, val: T) -> Option<T> {
self.map
.insert(TypeId::of::<T>(), Box::new(val))
.and_then(|boxed| (boxed as Box<dyn Any>).downcast().ok().map(|boxed| *boxed))
}
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)).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)).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>).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()
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_extensions() {
#[derive(Debug, PartialEq)]
struct MyType(i32);
let mut map = Extensions::new();
map.insert(5i32);
map.insert(MyType(10));
assert_eq!(map.get(), Some(&5i32));
assert_eq!(map.get_mut(), Some(&mut 5i32));
assert_eq!(map.remove::<i32>(), Some(5i32));
assert!(map.get::<i32>().is_none());
assert_eq!(map.get::<bool>(), None);
assert_eq!(map.get(), Some(&MyType(10)));
}
}