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Merge pull request #166 from jonhartnett/master
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Remove KeyRef from the public api
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@jeromefroe
jeromefroe authored Mar 4, 2023
2 parents 69d703e + 0aa9342 commit 7890848
Showing 1 changed file with 42 additions and 53 deletions.
95 changes: 42 additions & 53 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -58,7 +58,6 @@
//! ```

#![no_std]
#![cfg_attr(feature = "nightly", feature(negative_impls, auto_traits))]

#[cfg(feature = "hashbrown")]
extern crate hashbrown;
Expand Down Expand Up @@ -88,8 +87,7 @@ use std::collections::HashMap;
extern crate alloc;

// Struct used to hold a reference to a key
#[doc(hidden)]
pub struct KeyRef<K> {
struct KeyRef<K> {
k: *const K,
}

Expand All @@ -107,49 +105,40 @@ impl<K: PartialEq> PartialEq for KeyRef<K> {

impl<K: Eq> Eq for KeyRef<K> {}

#[cfg(feature = "nightly")]
#[doc(hidden)]
pub auto trait NotKeyRef {}
// This type exists to allow a "blanket" Borrow impl for KeyRef without conflicting with the
// stdlib blanket impl
#[repr(transparent)]
struct KeyWrapper<K: ?Sized>(K);

#[cfg(feature = "nightly")]
impl<K> !NotKeyRef for KeyRef<K> {}

#[cfg(feature = "nightly")]
impl<K, D> Borrow<D> for KeyRef<K>
where
K: Borrow<D>,
D: NotKeyRef + ?Sized,
{
fn borrow(&self) -> &D {
unsafe { &*self.k }.borrow()
impl<K: ?Sized> KeyWrapper<K> {
fn from_ref(key: &K) -> &Self {
// safety: KeyWrapper is transparent, so casting the ref like this is allowable
unsafe { &*(key as *const K as *const KeyWrapper<K>) }
}
}

#[cfg(not(feature = "nightly"))]
impl<K> Borrow<K> for KeyRef<K> {
fn borrow(&self) -> &K {
unsafe { &*self.k }
impl<K: ?Sized + Hash> Hash for KeyWrapper<K> {
fn hash<H: Hasher>(&self, state: &mut H) {
self.0.hash(state)
}
}

#[cfg(not(feature = "nightly"))]
impl Borrow<str> for KeyRef<alloc::string::String> {
fn borrow(&self) -> &str {
unsafe { &*self.k }
impl<K: ?Sized + PartialEq> PartialEq for KeyWrapper<K> {
fn eq(&self, other: &Self) -> bool {
self.0.eq(&other.0)
}
}

#[cfg(not(feature = "nightly"))]
impl<T: ?Sized> Borrow<T> for KeyRef<Box<T>> {
fn borrow(&self) -> &T {
unsafe { &*self.k }
}
}
impl<K: ?Sized + Eq> Eq for KeyWrapper<K> {}

#[cfg(not(feature = "nightly"))]
impl<T> Borrow<[T]> for KeyRef<alloc::vec::Vec<T>> {
fn borrow(&self) -> &[T] {
unsafe { &*self.k }
impl<K, Q> Borrow<KeyWrapper<Q>> for KeyRef<K>
where
K: Borrow<Q>,
Q: ?Sized,
{
fn borrow(&self) -> &KeyWrapper<Q> {
let key = unsafe { &*self.k }.borrow();
KeyWrapper::from_ref(key)
}
}

Expand Down Expand Up @@ -422,10 +411,10 @@ impl<K: Hash + Eq, V, S: BuildHasher> LruCache<K, V, S> {
/// ```
pub fn get<'a, Q>(&'a mut self, k: &Q) -> Option<&'a V>
where
KeyRef<K>: Borrow<Q>,
K: Borrow<Q>,
Q: Hash + Eq + ?Sized,
{
if let Some(node) = self.map.get_mut(k) {
if let Some(node) = self.map.get_mut(KeyWrapper::from_ref(k)) {
let node_ptr: *mut LruEntry<K, V> = node.as_ptr();

self.detach(node_ptr);
Expand Down Expand Up @@ -458,10 +447,10 @@ impl<K: Hash + Eq, V, S: BuildHasher> LruCache<K, V, S> {
/// ```
pub fn get_mut<'a, Q>(&'a mut self, k: &Q) -> Option<&'a mut V>
where
KeyRef<K>: Borrow<Q>,
K: Borrow<Q>,
Q: Hash + Eq + ?Sized,
{
if let Some(node) = self.map.get_mut(k) {
if let Some(node) = self.map.get_mut(KeyWrapper::from_ref(k)) {
let node_ptr: *mut LruEntry<K, V> = node.as_ptr();

self.detach(node_ptr);
Expand Down Expand Up @@ -584,11 +573,11 @@ impl<K: Hash + Eq, V, S: BuildHasher> LruCache<K, V, S> {
/// ```
pub fn peek<'a, Q>(&'a self, k: &Q) -> Option<&'a V>
where
KeyRef<K>: Borrow<Q>,
K: Borrow<Q>,
Q: Hash + Eq + ?Sized,
{
self.map
.get(k)
.get(KeyWrapper::from_ref(k))
.map(|node| unsafe { &*node.as_ref().val.as_ptr() })
}

Expand All @@ -611,10 +600,10 @@ impl<K: Hash + Eq, V, S: BuildHasher> LruCache<K, V, S> {
/// ```
pub fn peek_mut<'a, Q>(&'a mut self, k: &Q) -> Option<&'a mut V>
where
KeyRef<K>: Borrow<Q>,
K: Borrow<Q>,
Q: Hash + Eq + ?Sized,
{
match self.map.get_mut(k) {
match self.map.get_mut(KeyWrapper::from_ref(k)) {
None => None,
Some(node) => Some(unsafe { &mut *(*node.as_ptr()).val.as_mut_ptr() }),
}
Expand Down Expand Up @@ -671,10 +660,10 @@ impl<K: Hash + Eq, V, S: BuildHasher> LruCache<K, V, S> {
/// ```
pub fn contains<Q>(&self, k: &Q) -> bool
where
KeyRef<K>: Borrow<Q>,
K: Borrow<Q>,
Q: Hash + Eq + ?Sized,
{
self.map.contains_key(k)
self.map.contains_key(KeyWrapper::from_ref(k))
}

/// Removes and returns the value corresponding to the key from the cache or
Expand All @@ -696,10 +685,10 @@ impl<K: Hash + Eq, V, S: BuildHasher> LruCache<K, V, S> {
/// ```
pub fn pop<Q>(&mut self, k: &Q) -> Option<V>
where
KeyRef<K>: Borrow<Q>,
K: Borrow<Q>,
Q: Hash + Eq + ?Sized,
{
match self.map.remove(k) {
match self.map.remove(KeyWrapper::from_ref(k)) {
None => None,
Some(old_node) => {
let mut old_node = unsafe {
Expand Down Expand Up @@ -738,10 +727,10 @@ impl<K: Hash + Eq, V, S: BuildHasher> LruCache<K, V, S> {
/// ```
pub fn pop_entry<Q>(&mut self, k: &Q) -> Option<(K, V)>
where
KeyRef<K>: Borrow<Q>,
K: Borrow<Q>,
Q: Hash + Eq + ?Sized,
{
match self.map.remove(k) {
match self.map.remove(KeyWrapper::from_ref(k)) {
None => None,
Some(old_node) => {
let mut old_node = unsafe { *Box::from_raw(old_node.as_ptr()) };
Expand Down Expand Up @@ -806,10 +795,10 @@ impl<K: Hash + Eq, V, S: BuildHasher> LruCache<K, V, S> {
/// ```
pub fn promote<'a, Q>(&'a mut self, k: &Q)
where
KeyRef<K>: Borrow<Q>,
K: Borrow<Q>,
Q: Hash + Eq + ?Sized,
{
if let Some(node) = self.map.get_mut(k) {
if let Some(node) = self.map.get_mut(KeyWrapper::from_ref(k)) {
let node_ptr: *mut LruEntry<K, V> = node.as_ptr();
self.detach(node_ptr);
self.attach(node_ptr);
Expand Down Expand Up @@ -842,10 +831,10 @@ impl<K: Hash + Eq, V, S: BuildHasher> LruCache<K, V, S> {
/// ```
pub fn demote<'a, Q>(&'a mut self, k: &Q)
where
KeyRef<K>: Borrow<Q>,
K: Borrow<Q>,
Q: Hash + Eq + ?Sized,
{
if let Some(node) = self.map.get_mut(k) {
if let Some(node) = self.map.get_mut(KeyWrapper::from_ref(k)) {
let node_ptr: *mut LruEntry<K, V> = node.as_ptr();
self.detach(node_ptr);
self.attach_last(node_ptr);
Expand Down

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