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use core::{future, marker::PhantomData};
use crate::CastIdentityBorrowed;
/// Async specialized behavior runner (Borrowed -> Borrowed)
#[derive(Debug)]
pub struct AsyncSpecializerBorrowed<T, U, F>(T, F, PhantomData<fn(T) -> U>);
impl<T, U, F> AsyncSpecializerBorrowed<T, U, F>
where
F: AsyncFnOnce(T) -> U,
T: CastIdentityBorrowed<T>,
U: CastIdentityBorrowed<U>,
{
/// Create a new specializer with a fallback function.
#[inline(always)]
pub const fn new(params: T, f: F) -> Self {
Self(params, f, PhantomData)
}
/// Specialize on the parameter and the return type of the closure.
///
/// ```rust
/// use pasts::Executor;
/// use specializer::{CastIdentityBorrowed, AsyncSpecializerBorrowed};
///
/// async fn specialized<'a, T, U>(a: &'a mut T, b: &'a u32)
/// -> Option<&'a U>
/// where
/// T: 'static,
/// U: 'static,
/// {
/// AsyncSpecializerBorrowed::new(a, async |_ty| None)
/// .specialize(async |int: &mut i32| -> Option<&i32> {
/// Some(&*int)
/// })
/// .specialize(async |int: &mut u32| -> Option<&u32> {
/// Some(&*b)
/// })
/// .run()
/// .await
/// }
///
/// Executor::default().block_on(async {
/// assert_eq!(specialized::<i32, i32>(&mut 3, &5).await, Some(&3));
/// assert_eq!(specialized::<u32, u32>(&mut 3, &5).await, Some(&5));
/// assert_eq!(specialized::<(), u32>(&mut (), &5).await, None);
/// })
/// ```
#[inline]
pub fn specialize<P, R>(
self,
f: impl AsyncFnOnce(P) -> R,
) -> AsyncSpecializerBorrowed<T, U, impl AsyncFnOnce(T) -> U>
where
T: CastIdentityBorrowed<P>,
R: CastIdentityBorrowed<U>,
{
let AsyncSpecializerBorrowed(ty, fallback, phantom_data) = self;
let f = async |t: T| -> U {
if <R as CastIdentityBorrowed<U>>::is_same()
&& <T as CastIdentityBorrowed<P>>::is_same()
{
let param = crate::cast_identity_borrowed::<T, P>(t).unwrap();
return crate::cast_identity_borrowed::<R, U>(f(param).await)
.unwrap();
}
fallback(t).await
};
AsyncSpecializerBorrowed(ty, f, phantom_data)
}
/// Specialize on the parameter and the return type of the closure, mapping
/// both.
///
/// ```rust
/// use std::future;
///
/// use pasts::Executor;
/// use specializer::AsyncSpecializerBorrowed;
///
/// async fn specialized<'a, T, U>(a: &'a mut T, b: &'a U) -> &'a U
/// where
/// T: 'static + Clone,
/// U: 'static + From<T> + From<u8>,
/// {
/// let to = async |ty: &mut T| -> &U { b };
///
/// AsyncSpecializerBorrowed::new(a, to)
/// .specialize(async |int: &mut i32| -> &i32 {
/// *int *= 2;
/// &*int
/// })
/// .specialize_map(
/// async |int: &mut u8| {
/// *int *= 3;
/// int
/// },
/// to,
/// future::ready::<&U>,
/// )
/// .run()
/// .await
/// }
///
/// Executor::default().block_on(async {
/// let mut value = 3;
///
/// assert_eq!(specialized::<u8, i32>(&mut value, &5).await, &mut 5);
/// assert_eq!(value, 9);
///
/// let mut value = 3;
///
/// assert_eq!(specialized::<i32, i32>(&mut value, &5).await, &mut 6);
/// assert_eq!(value, 6);
///
/// let mut value = 3;
///
/// assert_eq!(specialized::<i16, i32>(&mut value, &5).await, &mut 5);
/// assert_eq!(value, 3);
/// });
/// ```
#[inline]
pub fn specialize_map<P, R>(
self,
p: impl AsyncFnOnce(P) -> P,
f: impl AsyncFnOnce(T) -> U,
r: impl AsyncFnOnce(R) -> R,
) -> AsyncSpecializerBorrowed<T, U, impl AsyncFnOnce(T) -> U>
where
T: CastIdentityBorrowed<P>,
P: CastIdentityBorrowed<T>,
R: CastIdentityBorrowed<U>,
U: CastIdentityBorrowed<R>,
{
let AsyncSpecializerBorrowed(ty, fallback, phantom_data) = self;
let f = async |t: T| -> U {
if <U as CastIdentityBorrowed<R>>::is_same()
&& <T as CastIdentityBorrowed<P>>::is_same()
{
let param = crate::cast_identity_borrowed::<T, P>(t).unwrap();
let param =
crate::cast_identity_borrowed::<P, T>(p(param).await)
.unwrap();
let ret = crate::cast_identity_borrowed::<U, R>(f(param).await)
.unwrap();
return crate::cast_identity_borrowed::<R, U>(r(ret).await)
.unwrap();
}
fallback(t).await
};
AsyncSpecializerBorrowed(ty, f, phantom_data)
}
/// Specialize on the parameter of the closure.
///
/// ```rust
/// use pasts::Executor;
/// use specializer::{CastIdentityBorrowed, AsyncSpecializerBorrowed};
///
/// async fn specialized<'a, T, U>(a: &'a mut T, b: &'a U) -> Option<&'a U>
/// where
/// T: 'static,
/// U: 'static,
/// {
/// AsyncSpecializerBorrowed::new(a, async |_ty| None)
/// .specialize_param(async |int: &mut u32| Some(b))
/// .run()
/// .await
/// }
///
/// Executor::default().block_on(async {
/// assert_eq!(specialized::<i32, i32>(&mut 3, &5).await, None);
/// assert_eq!(specialized::<u32, u32>(&mut 3, &5).await, Some(&5));
/// });
/// ```
#[inline]
pub fn specialize_param<P>(
self,
f: impl AsyncFnOnce(P) -> U,
) -> AsyncSpecializerBorrowed<T, U, impl AsyncFnOnce(T) -> U>
where
T: CastIdentityBorrowed<P>,
{
self.specialize::<P, U>(f)
}
/// Specialize on the return type of the closure.
///
/// ```rust
/// use pasts::Executor;
/// use specializer::{CastIdentityBorrowed, AsyncSpecializerBorrowed};
///
/// async fn specialized<'a, U>(a: &'a mut i32, b: &'a u32) -> Option<&'a U>
/// where
/// U: 'static,
/// {
/// AsyncSpecializerBorrowed::new(a, async |_ty| None)
/// .specialize_return(async |int| -> Option<&i32> { Some(&*int) })
/// .specialize_return(async |int| -> Option<&u32> { Some(&*b) })
/// .run()
/// .await
/// }
///
/// Executor::default().block_on(async {
/// assert_eq!(specialized(&mut 3, &5).await, Some(&3i32));
/// assert_eq!(specialized(&mut 3, &5).await, Some(&5u32));
/// assert_eq!(specialized::<u8>(&mut 3, &5).await, None);
/// })
/// ```
#[inline]
pub fn specialize_return<R>(
self,
f: impl AsyncFnOnce(T) -> R,
) -> AsyncSpecializerBorrowed<T, U, impl AsyncFnOnce(T) -> U>
where
R: CastIdentityBorrowed<U>,
{
self.specialize::<T, R>(f)
}
/// Specialize on the parameter and the return type of the closure, mapping
/// the parameter.
///
/// ```rust
/// use std::convert;
///
/// use pasts::Executor;
/// use specializer::AsyncSpecializerBorrowed;
///
/// async fn specialized<'a, T, U>(a: &'a mut T, b: &'a U) -> &'a U
/// where
/// T: 'static + Clone,
/// U: 'static + From<T> + From<u8>,
/// {
/// let to = async |ty: &mut T| -> &U { b };
///
/// AsyncSpecializerBorrowed::new(a, to)
/// .specialize(async |int: &mut i32| -> &i32 {
/// *int *= 2;
/// &*int
/// })
/// .specialize_map_param(
/// async |int: &mut u8| {
/// *int *= 3;
/// int
/// },
/// to,
/// )
/// .run()
/// .await
/// }
///
/// Executor::default().block_on(async {
/// let mut value = 3;
///
/// assert_eq!(specialized::<u8, i32>(&mut value, &5).await, &mut 5);
/// assert_eq!(value, 9);
///
/// let mut value = 3;
///
/// assert_eq!(specialized::<i32, i32>(&mut value, &5).await, &mut 6);
/// assert_eq!(value, 6);
///
/// let mut value = 3;
///
/// assert_eq!(specialized::<i16, i32>(&mut value, &5).await, &mut 5);
/// assert_eq!(value, 3);
/// });
/// ```
#[inline]
pub fn specialize_map_param<P>(
self,
p: impl AsyncFnOnce(P) -> P,
f: impl AsyncFnOnce(T) -> U,
) -> AsyncSpecializerBorrowed<T, U, impl AsyncFnOnce(T) -> U>
where
T: CastIdentityBorrowed<P>,
P: CastIdentityBorrowed<T>,
{
self.specialize_map::<P, U>(p, f, future::ready)
}
/// Specialize on the parameter and the return type of the closure, mapping
/// the parameter.
///
/// ```rust
/// use std::convert;
///
/// use pasts::Executor;
/// use specializer::AsyncSpecializerBorrowed;
///
/// async fn specialized<'a, U>(a: &'a mut i8, b: &'a i32, c: &'a U)
/// -> &'a U
/// where
/// U: 'static,
/// {
/// let to = async |ty: &mut i8| -> &U {
/// *ty *= 3;
/// c
/// };
///
/// AsyncSpecializerBorrowed::new(a, to)
/// .specialize_return(async |int| -> &i8 {
/// *int *= 2;
/// &*int
/// })
/// .specialize_map_return(
/// to,
/// async |ty| -> &i32 { b },
/// )
/// .specialize_map_return(
/// async |ty| -> &U { c },
/// async |ty| -> &i16 { &15 },
/// )
/// .run()
/// .await
/// }
///
/// Executor::default().block_on(async {
/// let mut value = 3;
///
/// assert_eq!(specialized::<i8>(&mut value, &5, &42).await, &6);
/// assert_eq!(value, 6);
///
/// let mut value = 3;
///
/// assert_eq!(specialized::<i64>(&mut value, &5, &42).await, &42);
/// assert_eq!(value, 9);
///
/// let mut value = 3;
///
/// assert_eq!(specialized::<i32>(&mut value, &5, &42).await, &5);
/// assert_eq!(value, 9);
///
/// let mut value = 3;
///
/// assert_eq!(specialized::<i16>(&mut value, &5, &42).await, &15);
/// assert_eq!(value, 3);
/// });
/// ```
#[inline]
pub fn specialize_map_return<R>(
self,
f: impl AsyncFnOnce(T) -> U,
r: impl AsyncFnOnce(R) -> R,
) -> AsyncSpecializerBorrowed<T, U, impl AsyncFnOnce(T) -> U>
where
R: CastIdentityBorrowed<U>,
U: CastIdentityBorrowed<R>,
{
self.specialize_map::<T, R>(future::ready, f, r)
}
/// Run the specializer.
#[inline]
pub async fn run(self) -> U {
(self.1)(self.0).await
}
}