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use std::any::{Any, TypeId};
use std::collections::HashMap;
use std::hash::BuildHasherDefault;
use std::fmt;
use fnv::FnvHasher;
type AnyMap = HashMap<TypeId, Box<Any + Send + Sync>, BuildHasherDefault<FnvHasher>>;
/// A type map of protocol extensions.
///
/// `Extensions` can be used by `Request` and `Response` to store
/// extra data derived from the underlying protocol.
#[derive(Default)]
pub struct Extensions {
map: AnyMap,
}
impl Extensions {
/// Create an empty `Extensions`.
#[inline]
pub fn new() -> Extensions {
Extensions {
map: HashMap::default(),
}
}
/// Insert a type into this `Extensions`.
///
/// If a extension of this type already existed, it will
/// be returned.
///
/// # Example
///
/// ```
/// # use http::Extensions;
/// let mut ext = Extensions::new();
/// assert!(ext.insert(5i32).is_none());
/// assert!(ext.insert(4u8).is_none());
/// assert_eq!(ext.insert(9i32), Some(5i32));
/// ```
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| {
//TODO: we can use unsafe and remove double checking the type id
(boxed as Box<Any + 'static>)
.downcast()
.ok()
.map(|boxed| *boxed)
})
}
/// Get a reference to a type previously inserted on this `Extensions`.
///
/// # Example
///
/// ```
/// # use http::Extensions;
/// let mut ext = Extensions::new();
/// assert!(ext.get::<i32>().is_none());
/// ext.insert(5i32);
///
/// assert_eq!(ext.get::<i32>(), Some(&5i32));
/// ```
pub fn get<T: Send + Sync + 'static>(&self) -> Option<&T> {
self.map.get(&TypeId::of::<T>())
//TODO: we can use unsafe and remove double checking the type id
.and_then(|boxed| (&**boxed as &(Any + 'static)).downcast_ref())
}
/// Get a mutable reference to a type previously inserted on this `Extensions`.
///
/// # Example
///
/// ```
/// # use http::Extensions;
/// let mut ext = Extensions::new();
/// ext.insert(String::from("Hello"));
/// ext.get_mut::<String>().unwrap().push_str(" World");
///
/// assert_eq!(ext.get::<String>().unwrap(), "Hello World");
/// ```
pub fn get_mut<T: Send + Sync + 'static>(&mut self) -> Option<&mut T> {
self.map.get_mut(&TypeId::of::<T>())
//TODO: we can use unsafe and remove double checking the type id
.and_then(|boxed| (&mut **boxed as &mut (Any + 'static)).downcast_mut())
}
/// Remove a type from this `Extensions`.
///
/// If a extension of this type existed, it will be returned.
///
/// # Example
///
/// ```
/// # use http::Extensions;
/// let mut ext = Extensions::new();
/// ext.insert(5i32);
/// assert_eq!(ext.remove::<i32>(), Some(5i32));
/// assert!(ext.get::<i32>().is_none());
/// ```
pub fn remove<T: Send + Sync + 'static>(&mut self) -> Option<T> {
self.map.remove(&TypeId::of::<T>())
.and_then(|boxed| {
//TODO: we can use unsafe and remove double checking the type id
(boxed as Box<Any + 'static>)
.downcast()
.ok()
.map(|boxed| *boxed)
})
}
/// Clear the `Extensions` of all inserted extensions.
///
/// # Example
///
/// ```
/// # use http::Extensions;
/// let mut ext = Extensions::new();
/// ext.insert(5i32);
/// ext.clear();
///
/// assert!(ext.get::<i32>().is_none());
/// ```
#[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)));
}