| // HACK(eddyb) this is a copy of `syntax::ptr`, minus the mutation (the HIR is |
| // frozen anyway). The only reason for doing this instead of replacing `P<T>` |
| // with `Box<T>` in HIR, is that `&Box<[T]>` doesn't implement `IntoIterator`. |
| |
| use std::fmt::{self, Display, Debug}; |
| use std::iter::FromIterator; |
| use std::ops::Deref; |
| use std::{slice, vec}; |
| |
| use rustc_serialize::{Encodable, Decodable, Encoder, Decoder}; |
| |
| use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult, |
| HashStable}; |
| /// An owned smart pointer. |
| #[derive(Hash, PartialEq, Eq)] |
| pub struct P<T: ?Sized> { |
| ptr: Box<T> |
| } |
| |
| /// Construct a `P<T>` from a `T` value. |
| #[allow(non_snake_case)] |
| pub fn P<T: 'static>(value: T) -> P<T> { |
| P { |
| ptr: box value |
| } |
| } |
| |
| impl<T: 'static> P<T> { |
| // HACK(eddyb) used by HIR lowering in a few places still. |
| // NOTE: do not make this more public than `pub(super)`. |
| pub(super) fn into_inner(self) -> T { |
| *self.ptr |
| } |
| } |
| |
| impl<T: ?Sized> Deref for P<T> { |
| type Target = T; |
| |
| fn deref(&self) -> &T { |
| &self.ptr |
| } |
| } |
| |
| impl<T: ?Sized + Debug> Debug for P<T> { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| Debug::fmt(&self.ptr, f) |
| } |
| } |
| |
| impl<T: Display> Display for P<T> { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| Display::fmt(&**self, f) |
| } |
| } |
| |
| impl<T: 'static + Decodable> Decodable for P<T> { |
| fn decode<D: Decoder>(d: &mut D) -> Result<P<T>, D::Error> { |
| Decodable::decode(d).map(P) |
| } |
| } |
| |
| impl<T: Encodable> Encodable for P<T> { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| (**self).encode(s) |
| } |
| } |
| |
| impl<T> P<[T]> { |
| pub const fn new() -> P<[T]> { |
| // HACK(eddyb) bypass the lack of a `const fn` to create an empty `Box<[T]>` |
| // (as trait methods, `default` in this case, can't be `const fn` yet). |
| P { |
| ptr: unsafe { |
| use std::ptr::NonNull; |
| std::mem::transmute(NonNull::<[T; 0]>::dangling() as NonNull<[T]>) |
| }, |
| } |
| } |
| |
| #[inline(never)] |
| pub fn from_vec(v: Vec<T>) -> P<[T]> { |
| P { ptr: v.into_boxed_slice() } |
| } |
| |
| // HACK(eddyb) used by HIR lowering in a few places still. |
| // NOTE: do not make this more public than `pub(super)`, |
| // and do not make this into an `IntoIterator` impl. |
| pub(super) fn into_iter(self) -> vec::IntoIter<T> { |
| self.ptr.into_vec().into_iter() |
| } |
| } |
| |
| |
| impl<T> Default for P<[T]> { |
| /// Creates an empty `P<[T]>`. |
| fn default() -> P<[T]> { |
| P::new() |
| } |
| } |
| |
| impl<T> From<Vec<T>> for P<[T]> { |
| fn from(v: Vec<T>) -> Self { |
| P::from_vec(v) |
| } |
| } |
| |
| impl<T> FromIterator<T> for P<[T]> { |
| fn from_iter<I: IntoIterator<Item=T>>(iter: I) -> P<[T]> { |
| P::from_vec(iter.into_iter().collect()) |
| } |
| } |
| |
| impl<'a, T> IntoIterator for &'a P<[T]> { |
| type Item = &'a T; |
| type IntoIter = slice::Iter<'a, T>; |
| fn into_iter(self) -> Self::IntoIter { |
| self.ptr.into_iter() |
| } |
| } |
| |
| impl<T: Encodable> Encodable for P<[T]> { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| Encodable::encode(&**self, s) |
| } |
| } |
| |
| impl<T: Decodable> Decodable for P<[T]> { |
| fn decode<D: Decoder>(d: &mut D) -> Result<P<[T]>, D::Error> { |
| Ok(P::from_vec(Decodable::decode(d)?)) |
| } |
| } |
| |
| impl<CTX, T> HashStable<CTX> for P<T> |
| where T: ?Sized + HashStable<CTX> |
| { |
| fn hash_stable<W: StableHasherResult>(&self, |
| hcx: &mut CTX, |
| hasher: &mut StableHasher<W>) { |
| (**self).hash_stable(hcx, hasher); |
| } |
| } |