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