use super::Cached;
use std::cmp::Eq;
use std::hash::Hash;
#[cfg(feature = "ahash")]
use hashbrown::{hash_map::Entry, HashMap};
#[cfg(not(feature = "ahash"))]
use std::collections::{hash_map::Entry, HashMap};
#[cfg(feature = "async")]
use {super::CachedAsync, async_trait::async_trait, futures::Future};
#[derive(Clone, Debug)]
pub struct UnboundCache<K, V> {
pub(super) store: HashMap<K, V>,
pub(super) hits: u64,
pub(super) misses: u64,
pub(super) initial_capacity: Option<usize>,
}
impl<K, V> PartialEq for UnboundCache<K, V>
where
K: Eq + Hash,
V: PartialEq,
{
fn eq(&self, other: &UnboundCache<K, V>) -> bool {
self.store.eq(&other.store)
}
}
impl<K, V> Eq for UnboundCache<K, V>
where
K: Eq + Hash,
V: PartialEq,
{
}
impl<K: Hash + Eq, V> UnboundCache<K, V> {
#[allow(clippy::new_without_default)]
#[must_use]
pub fn new() -> UnboundCache<K, V> {
UnboundCache {
store: Self::new_store(None),
hits: 0,
misses: 0,
initial_capacity: None,
}
}
#[must_use]
pub fn with_capacity(size: usize) -> UnboundCache<K, V> {
UnboundCache {
store: Self::new_store(Some(size)),
hits: 0,
misses: 0,
initial_capacity: Some(size),
}
}
fn new_store(capacity: Option<usize>) -> HashMap<K, V> {
capacity.map_or_else(HashMap::new, HashMap::with_capacity)
}
#[must_use]
pub fn get_store(&self) -> &HashMap<K, V> {
&self.store
}
}
impl<K: Hash + Eq, V> Cached<K, V> for UnboundCache<K, V> {
fn cache_get<Q>(&mut self, key: &Q) -> Option<&V>
where
K: std::borrow::Borrow<Q>,
Q: std::hash::Hash + Eq + ?Sized,
{
if let Some(v) = self.store.get(key) {
self.hits += 1;
Some(v)
} else {
self.misses += 1;
None
}
}
fn cache_get_mut<Q>(&mut self, key: &Q) -> std::option::Option<&mut V>
where
K: std::borrow::Borrow<Q>,
Q: std::hash::Hash + Eq + ?Sized,
{
if let Some(v) = self.store.get_mut(key) {
self.hits += 1;
Some(v)
} else {
self.misses += 1;
None
}
}
fn cache_set(&mut self, key: K, val: V) -> Option<V> {
self.store.insert(key, val)
}
fn cache_get_or_set_with<F: FnOnce() -> V>(&mut self, key: K, f: F) -> &mut V {
match self.store.entry(key) {
Entry::Occupied(occupied) => {
self.hits += 1;
occupied.into_mut()
}
Entry::Vacant(vacant) => {
self.misses += 1;
vacant.insert(f())
}
}
}
fn cache_try_get_or_set_with<F: FnOnce() -> Result<V, E>, E>(
&mut self,
k: K,
f: F,
) -> Result<&mut V, E> {
match self.store.entry(k) {
Entry::Occupied(occupied) => {
self.hits += 1;
Ok(occupied.into_mut())
}
Entry::Vacant(vacant) => {
self.misses += 1;
Ok(vacant.insert(f()?))
}
}
}
fn cache_remove<Q>(&mut self, k: &Q) -> Option<V>
where
K: std::borrow::Borrow<Q>,
Q: std::hash::Hash + Eq + ?Sized,
{
self.store.remove(k)
}
fn cache_clear(&mut self) {
self.store.clear();
}
fn cache_reset(&mut self) {
self.store = Self::new_store(self.initial_capacity);
}
fn cache_reset_metrics(&mut self) {
self.misses = 0;
self.hits = 0;
}
fn cache_size(&self) -> usize {
self.store.len()
}
fn cache_hits(&self) -> Option<u64> {
Some(self.hits)
}
fn cache_misses(&self) -> Option<u64> {
Some(self.misses)
}
}
#[cfg(feature = "async")]
#[async_trait]
impl<K, V> CachedAsync<K, V> for UnboundCache<K, V>
where
K: Hash + Eq + Clone + Send,
{
async fn get_or_set_with<F, Fut>(&mut self, key: K, f: F) -> &mut V
where
V: Send,
F: FnOnce() -> Fut + Send,
Fut: Future<Output = V> + Send,
{
match self.store.entry(key) {
Entry::Occupied(occupied) => {
self.hits += 1;
occupied.into_mut()
}
Entry::Vacant(vacant) => {
self.misses += 1;
vacant.insert(f().await)
}
}
}
async fn try_get_or_set_with<F, Fut, E>(&mut self, key: K, f: F) -> Result<&mut V, E>
where
V: Send,
F: FnOnce() -> Fut + Send,
Fut: Future<Output = Result<V, E>> + Send,
{
let v = match self.store.entry(key) {
Entry::Occupied(occupied) => {
self.hits += 1;
occupied.into_mut()
}
Entry::Vacant(vacant) => {
self.misses += 1;
vacant.insert(f().await?)
}
};
Ok(v)
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn basic_cache() {
let mut c = UnboundCache::new();
assert!(c.cache_get(&1).is_none());
let misses = c.cache_misses().unwrap();
assert_eq!(1, misses);
assert_eq!(c.cache_set(1, 100), None);
assert!(c.cache_get(&1).is_some());
let hits = c.cache_hits().unwrap();
let misses = c.cache_misses().unwrap();
assert_eq!(1, hits);
assert_eq!(1, misses);
}
#[test]
fn clear() {
let mut c = UnboundCache::new();
assert_eq!(c.cache_set(1, 100), None);
assert_eq!(c.cache_set(2, 200), None);
assert_eq!(c.cache_set(3, 300), None);
c.cache_get(&1);
c.cache_get(&2);
c.cache_get(&3);
c.cache_get(&10);
c.cache_get(&20);
c.cache_get(&30);
assert_eq!(3, c.cache_size());
assert_eq!(3, c.cache_hits().unwrap());
assert_eq!(3, c.cache_misses().unwrap());
assert!(3 <= c.store.capacity());
c.cache_clear();
assert_eq!(0, c.cache_size());
assert_eq!(3, c.cache_hits().unwrap());
assert_eq!(3, c.cache_misses().unwrap());
assert!(3 <= c.store.capacity()); let capacity = 1;
let mut c = UnboundCache::with_capacity(capacity);
assert!(capacity <= c.store.capacity());
assert_eq!(c.cache_set(1, 100), None);
assert_eq!(c.cache_set(2, 200), None);
assert_eq!(c.cache_set(3, 300), None);
assert!(3 <= c.store.capacity());
c.cache_clear();
assert!(3 <= c.store.capacity()); }
#[test]
fn reset() {
let mut c = UnboundCache::new();
assert_eq!(c.cache_set(1, 100), None);
assert_eq!(c.cache_set(2, 200), None);
assert_eq!(c.cache_set(3, 300), None);
assert!(3 <= c.store.capacity());
c.cache_reset();
assert_eq!(0, c.store.capacity());
let init_capacity = 1;
let mut c = UnboundCache::with_capacity(init_capacity);
assert_eq!(c.cache_set(1, 100), None);
assert_eq!(c.cache_set(2, 200), None);
assert_eq!(c.cache_set(3, 300), None);
assert!(3 <= c.store.capacity());
c.cache_reset();
assert!(init_capacity <= c.store.capacity());
}
#[test]
fn remove() {
let mut c = UnboundCache::new();
assert_eq!(c.cache_set(1, 100), None);
assert_eq!(c.cache_set(2, 200), None);
assert_eq!(c.cache_set(3, 300), None);
c.cache_get(&1);
c.cache_get(&2);
c.cache_get(&3);
c.cache_get(&10);
c.cache_get(&20);
c.cache_get(&30);
assert_eq!(3, c.cache_size());
assert_eq!(3, c.cache_hits().unwrap());
assert_eq!(3, c.cache_misses().unwrap());
assert_eq!(Some(100), c.cache_remove(&1));
assert_eq!(2, c.cache_size());
assert_eq!(3, c.cache_hits().unwrap());
assert_eq!(3, c.cache_misses().unwrap());
assert_eq!(Some(200), c.cache_remove(&2));
assert_eq!(1, c.cache_size());
assert_eq!(None, c.cache_remove(&2));
assert_eq!(1, c.cache_size());
}
#[test]
fn get_or_set_with() {
let mut c = UnboundCache::new();
assert_eq!(c.cache_get_or_set_with(0, || 0), &0);
assert_eq!(c.cache_get_or_set_with(1, || 1), &1);
assert_eq!(c.cache_get_or_set_with(2, || 2), &2);
assert_eq!(c.cache_get_or_set_with(3, || 3), &3);
assert_eq!(c.cache_get_or_set_with(4, || 4), &4);
assert_eq!(c.cache_get_or_set_with(5, || 5), &5);
assert_eq!(c.cache_misses(), Some(6));
assert_eq!(c.cache_get_or_set_with(0, || 0), &0);
assert_eq!(c.cache_misses(), Some(6));
assert_eq!(c.cache_get_or_set_with(0, || 42), &0);
assert_eq!(c.cache_misses(), Some(6));
assert_eq!(c.cache_get_or_set_with(1, || 1), &1);
assert_eq!(c.cache_misses(), Some(6));
c.cache_reset();
fn _try_get(n: usize) -> Result<usize, String> {
if n < 10 {
Ok(n)
} else {
Err("dead".to_string())
}
}
let res: Result<&mut usize, String> = c.cache_try_get_or_set_with(0, || _try_get(10));
assert!(res.is_err());
let res: Result<&mut usize, String> = c.cache_try_get_or_set_with(0, || _try_get(1));
assert_eq!(res.unwrap(), &1);
let res: Result<&mut usize, String> = c.cache_try_get_or_set_with(0, || _try_get(5));
assert_eq!(res.unwrap(), &1);
}
}