//!
//! All relevant details are in the `RawMap` struct.
-use std::any::TypeId;
+use std::any::{Any, TypeId};
use std::borrow::Borrow;
use std::collections::hash_map::{self, HashMap};
-#[cfg(feature = "nightly")]
-use std::collections::hash_state::HashState;
-use std::default::Default;
+use std::convert::TryInto;
use std::hash::Hash;
-#[cfg(feature = "nightly")]
-use std::hash::Hasher;
-use std::iter::IntoIterator;
-#[cfg(feature = "nightly")]
+use std::hash::{Hasher, BuildHasherDefault};
+#[cfg(test)]
use std::mem;
use std::ops::{Index, IndexMut};
-#[cfg(feature = "nightly")]
-use std::ptr;
-use any::{Any, UncheckedAnyExt};
+use crate::any::UncheckedAnyExt;
-#[cfg(feature = "nightly")]
+#[derive(Default)]
struct TypeIdHasher {
value: u64,
}
-#[derive(Clone)]
-#[cfg(feature = "nightly")]
-struct TypeIdState;
-
-#[cfg(feature = "nightly")]
-impl HashState for TypeIdState {
- type Hasher = TypeIdHasher;
-
- fn hasher(&self) -> TypeIdHasher {
- TypeIdHasher { value: 0 }
- }
-}
-
-#[cfg(feature = "nightly")]
impl Hasher for TypeIdHasher {
- #[inline(always)]
+ #[inline]
fn write(&mut self, bytes: &[u8]) {
- // This expects to receive one and exactly one 64-bit value
- debug_assert!(bytes.len() == 8);
- unsafe {
- ptr::copy_nonoverlapping(&mut self.value, mem::transmute(&bytes[0]), 1)
- }
+ // This expects to receive exactly one 64-bit value, and there’s no realistic chance of
+ // that changing, but I don’t want to depend on something that isn’t expressly part of the
+ // contract for safety. But I’m OK with release builds putting everything in one bucket
+ // if it *did* change (and debug builds panicking).
+ debug_assert_eq!(bytes.len(), 8);
+ let _ = bytes.try_into()
+ .map(|array| self.value = u64::from_ne_bytes(array));
}
- #[inline(always)]
+ #[inline]
fn finish(&self) -> u64 { self.value }
}
+#[test]
+fn type_id_hasher() {
+ fn verify_hashing_with(type_id: TypeId) {
+ let mut hasher = TypeIdHasher::default();
+ type_id.hash(&mut hasher);
+ // SAFETY: u64 is valid for all bit patterns.
+ assert_eq!(hasher.finish(), unsafe { mem::transmute::<TypeId, u64>(type_id) });
+ }
+ // Pick a variety of types, just to demonstrate it’s all sane. Normal, zero-sized, unsized, &c.
+ verify_hashing_with(TypeId::of::<usize>());
+ verify_hashing_with(TypeId::of::<()>());
+ verify_hashing_with(TypeId::of::<str>());
+ verify_hashing_with(TypeId::of::<&str>());
+ verify_hashing_with(TypeId::of::<Vec<u8>>());
+}
/// The raw, underlying form of a `Map`.
///
/// contents of an `Map`. However, because you will then be dealing with `Any` trait objects, it
/// doesn’t tend to be so very useful. Still, if you need it, it’s here.
#[derive(Debug)]
-pub struct RawMap<A: ?Sized + UncheckedAnyExt = Any> {
- #[cfg(feature = "nightly")]
- inner: HashMap<TypeId, Box<A>, TypeIdState>,
-
- #[cfg(not(feature = "nightly"))]
- inner: HashMap<TypeId, Box<A>>,
+pub struct RawMap<A: ?Sized + UncheckedAnyExt = dyn Any> {
+ inner: HashMap<TypeId, Box<A>, BuildHasherDefault<TypeIdHasher>>,
}
// #[derive(Clone)] would want A to implement Clone, but in reality it’s only Box<A> that can.
impl<A: ?Sized + UncheckedAnyExt> Clone for RawMap<A> where Box<A>: Clone {
+ #[inline]
fn clone(&self) -> RawMap<A> {
RawMap {
inner: self.inner.clone(),
}
}
-impl<A: ?Sized + UncheckedAnyExt> Default for RawMap<A> {
- fn default() -> RawMap<A> {
- RawMap::new()
- }
-}
-
-#[cfg(feature = "nightly")]
impl_common_methods! {
field: RawMap.inner;
- new() => HashMap::with_hash_state(TypeIdState);
- with_capacity(capacity) => HashMap::with_capacity_and_hash_state(capacity, TypeIdState);
+ new() => HashMap::with_hasher(Default::default());
+ with_capacity(capacity) => HashMap::with_capacity_and_hasher(capacity, Default::default());
}
-#[cfg(not(feature = "nightly"))]
-impl_common_methods! {
- field: RawMap.inner;
- new() => HashMap::new();
- with_capacity(capacity) => HashMap::with_capacity(capacity);
-}
-
-/// RawMap iterator.
+/// `RawMap` iterator.
#[derive(Clone)]
pub struct Iter<'a, A: ?Sized + UncheckedAnyExt> {
inner: hash_map::Iter<'a, TypeId, Box<A>>,
#[inline] fn len(&self) -> usize { self.inner.len() }
}
-/// RawMap mutable iterator.
+/// `RawMap` mutable iterator.
pub struct IterMut<'a, A: ?Sized + UncheckedAnyExt> {
inner: hash_map::IterMut<'a, TypeId, Box<A>>,
}
#[inline] fn len(&self) -> usize { self.inner.len() }
}
-/// RawMap move iterator.
+/// `RawMap` move iterator.
pub struct IntoIter<A: ?Sized + UncheckedAnyExt> {
inner: hash_map::IntoIter<TypeId, Box<A>>,
}
#[inline] fn len(&self) -> usize { self.inner.len() }
}
-/// RawMap drain iterator.
-#[cfg(feature = "nightly")]
+/// `RawMap` drain iterator.
pub struct Drain<'a, A: ?Sized + UncheckedAnyExt> {
inner: hash_map::Drain<'a, TypeId, Box<A>>,
}
-#[cfg(feature = "nightly")]
impl<'a, A: ?Sized + UncheckedAnyExt> Iterator for Drain<'a, A> {
type Item = Box<A>;
#[inline] fn next(&mut self) -> Option<Box<A>> { self.inner.next().map(|x| x.1) }
#[inline] fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
}
-#[cfg(feature = "nightly")]
impl<'a, A: ?Sized + UncheckedAnyExt> ExactSizeIterator for Drain<'a, A> {
#[inline] fn len(&self) -> usize { self.inner.len() }
}
///
/// Keeps the allocated memory for reuse.
#[inline]
- #[cfg(feature = "nightly")]
pub fn drain(&mut self) -> Drain<A> {
Drain {
inner: self.inner.drain(),
}
/// Gets the entry for the given type in the collection for in-place manipulation.
+ #[inline]
pub fn entry(&mut self, key: TypeId) -> Entry<A> {
match self.inner.entry(key) {
hash_map::Entry::Occupied(e) => Entry::Occupied(OccupiedEntry {
///
/// The key may be any borrowed form of the map's key type, but `Hash` and `Eq` on the borrowed
/// form *must* match those for the key type.
+ #[inline]
pub fn get<Q: ?Sized>(&self, k: &Q) -> Option<&A>
where TypeId: Borrow<Q>, Q: Hash + Eq {
self.inner.get(k).map(|x| &**x)
///
/// The key may be any borrowed form of the map's key type, but `Hash` and `Eq` on the borrowed
/// form *must* match those for the key type.
+ #[inline]
pub fn contains_key<Q: ?Sized>(&self, k: &Q) -> bool
where TypeId: Borrow<Q>, Q: Hash + Eq {
self.inner.contains_key(k)
///
/// The key may be any borrowed form of the map's key type, but `Hash` and `Eq` on the borrowed
/// form *must* match those for the key type.
+ #[inline]
pub fn get_mut<Q: ?Sized>(&mut self, k: &Q) -> Option<&mut A>
where TypeId: Borrow<Q>, Q: Hash + Eq {
self.inner.get_mut(k).map(|x| &mut **x)
}
/// Inserts a key-value pair from the map. If the key already had a value present in the map,
- /// that value is returned. Otherwise, None is returned.
+ /// that value is returned. Otherwise, `None` is returned.
///
- /// It is the caller’s responsibility to ensure that the key corresponds with the type ID of
- /// the value. If they do not, memory safety may be violated.
+ /// # Safety
+ ///
+ /// `key` and the type ID of `value` must match, or *undefined behaviour* occurs.
+ #[inline]
pub unsafe fn insert(&mut self, key: TypeId, value: Box<A>) -> Option<Box<A>> {
self.inner.insert(key, value)
}
///
/// The key may be any borrowed form of the map's key type, but `Hash` and `Eq` on the borrowed
/// form *must* match those for the key type.
+ #[inline]
pub fn remove<Q: ?Sized>(&mut self, k: &Q) -> Option<Box<A>>
where TypeId: Borrow<Q>, Q: Hash + Eq {
self.inner.remove(k)
impl<A: ?Sized + UncheckedAnyExt, Q> Index<Q> for RawMap<A> where TypeId: Borrow<Q>, Q: Eq + Hash {
type Output = A;
- fn index<'a>(&'a self, index: Q) -> &'a A {
+ #[inline]
+ fn index(&self, index: Q) -> &A {
self.get(&index).expect("no entry found for key")
}
}
impl<A: ?Sized + UncheckedAnyExt, Q> IndexMut<Q> for RawMap<A> where TypeId: Borrow<Q>, Q: Eq + Hash {
- fn index_mut<'a>(&'a mut self, index: Q) -> &'a mut A {
+ #[inline]
+ fn index_mut(&mut self, index: Q) -> &mut A {
self.get_mut(&index).expect("no entry found for key")
}
}
type Item = Box<A>;
type IntoIter = IntoIter<A>;
+ #[inline]
fn into_iter(self) -> IntoIter<A> {
IntoIter {
inner: self.inner.into_iter(),
/// Ensures a value is in the entry by inserting the default if empty, and returns
/// a mutable reference to the value in the entry.
///
- /// It is the caller’s responsibility to ensure that the key of the entry corresponds with
- /// the type ID of `value`. If they do not, memory safety may be violated.
+ /// # Safety
+ ///
+ /// The type ID of `default` must match the entry’s key, or *undefined behaviour* occurs.
+ #[inline]
pub unsafe fn or_insert(self, default: Box<A>) -> &'a mut A {
match self {
Entry::Occupied(inner) => inner.into_mut(),
/// Ensures a value is in the entry by inserting the result of the default function if empty,
/// and returns a mutable reference to the value in the entry.
///
- /// It is the caller’s responsibility to ensure that the key of the entry corresponds with
- /// the type ID of `value`. If they do not, memory safety may be violated.
+ /// # Safety
+ ///
+ /// The type ID of the value returned by `default` must match the entry’s key,
+ /// or *undefined behaviour* occurs.
+ #[inline]
pub unsafe fn or_insert_with<F: FnOnce() -> Box<A>>(self, default: F) -> &'a mut A {
match self {
Entry::Occupied(inner) => inner.into_mut(),
impl<'a, A: ?Sized + UncheckedAnyExt> OccupiedEntry<'a, A> {
/// Gets a reference to the value in the entry.
+ #[inline]
pub fn get(&self) -> &A {
&**self.inner.get()
}
/// Gets a mutable reference to the value in the entry.
+ #[inline]
pub fn get_mut(&mut self) -> &mut A {
&mut **self.inner.get_mut()
}
/// Converts the OccupiedEntry into a mutable reference to the value in the entry
/// with a lifetime bound to the collection itself.
+ #[inline]
pub fn into_mut(self) -> &'a mut A {
&mut **self.inner.into_mut()
}
/// Sets the value of the entry, and returns the entry's old value.
///
- /// It is the caller’s responsibility to ensure that the key of the entry corresponds with
- /// the type ID of `value`. If they do not, memory safety may be violated.
+ /// # Safety
+ ///
+ /// The type ID of `value` must match the entry’s key, or *undefined behaviour* occurs.
+ #[inline]
pub unsafe fn insert(&mut self, value: Box<A>) -> Box<A> {
self.inner.insert(value)
}
/// Takes the value out of the entry, and returns it.
+ #[inline]
pub fn remove(self) -> Box<A> {
self.inner.remove()
}
impl<'a, A: ?Sized + UncheckedAnyExt> VacantEntry<'a, A> {
/// Sets the value of the entry with the VacantEntry's key,
- /// and returns a mutable reference to it
+ /// and returns a mutable reference to it.
///
- /// It is the caller’s responsibility to ensure that the key of the entry corresponds with
- /// the type ID of `value`. If they do not, memory safety may be violated.
+ /// # Safety
+ ///
+ /// The type ID of `value` must match the entry’s key, or *undefined behaviour* occurs.
+ #[inline]
pub unsafe fn insert(self, value: Box<A>) -> &'a mut A {
&mut **self.inner.insert(value)
}