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Add retain method #160

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Add retain method #160

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b24b67a
Add `retain` method
Rexagon Nov 5, 2021
cff1fd8
Fix imports
Rexagon Feb 13, 2022
43ce01d
Fix clippy warnings
Rexagon Apr 29, 2022
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4 changes: 2 additions & 2 deletions src/iter.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -82,7 +82,7 @@ where
let key = self.next_unexpired(now)?;
self.list.push_back(key);
let key = self.list.back()?;
let mut value = self.map.get_mut(&key)?;
let mut value = self.map.get_mut(key)?;
value.1 = now;

unsafe {
Expand Down Expand Up @@ -225,7 +225,7 @@ where
let now = Instant::now();
self.next_unexpired(now)?;
let key = &self.list[self.item_index];
let value = self.map.get(&key)?;
let value = self.map.get(key)?;

unsafe {
let key = std::mem::transmute::<&Key, &'a Key>(key);
Expand Down
68 changes: 57 additions & 11 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -85,6 +85,7 @@
#[cfg(feature = "sn_fake_clock")]
use sn_fake_clock::FakeClock as Instant;
use std::borrow::Borrow;
use std::collections::btree_map::Entry as BTreeMapEntry;
use std::collections::{BTreeMap, VecDeque};
use std::time::Duration;
#[cfg(not(feature = "sn_fake_clock"))]
Expand Down Expand Up @@ -325,6 +326,32 @@ where
PeekIter::new(&self.map, &self.list, self.time_to_live)
}

/// Retains only the elements specified by the predicate. Also removes expired elements
/// before passing them to the predicate.
pub fn retain<F>(&mut self, mut f: F)
where
F: FnMut((&'_ Key, &'_ Value)) -> bool,
{
let (map, list) = (&mut self.map, &mut self.list);

let now = Instant::now();
let ttl = self.time_to_live;

list.retain(|key| match map.entry(key.clone()) {
BTreeMapEntry::Occupied(entry) => {
if matches!(ttl, Some(ttl) if entry.get().1 + ttl < now)
|| !f((key, &entry.get().0))
{
let _ = entry.remove();
false
} else {
true
}
}
BTreeMapEntry::Vacant(_) => false,
});
}

// Move `key` in the ordered list to the last
fn update_key<Q: ?Sized>(list: &mut VecDeque<Key>, key: &Q)
where
Expand Down Expand Up @@ -511,7 +538,7 @@ mod test {
#[test]
fn size_only() {
let size = 10usize;
let mut lru_cache = super::LruCache::<usize, usize>::with_capacity(size);
let mut lru_cache = LruCache::<usize, usize>::with_capacity(size);

for i in 0..10 {
assert_eq!(lru_cache.len(), i);
Expand All @@ -534,7 +561,7 @@ mod test {
#[test]
fn time_only() {
let time_to_live = Duration::from_millis(100);
let mut lru_cache = super::LruCache::<usize, usize>::with_expiry_duration(time_to_live);
let mut lru_cache = LruCache::<usize, usize>::with_expiry_duration(time_to_live);

for i in 0..10 {
assert_eq!(lru_cache.len(), i);
Expand Down Expand Up @@ -562,7 +589,7 @@ mod test {
#[test]
fn time_only_check() {
let time_to_live = Duration::from_millis(50);
let mut lru_cache = super::LruCache::<usize, usize>::with_expiry_duration(time_to_live);
let mut lru_cache = LruCache::<usize, usize>::with_expiry_duration(time_to_live);

assert_eq!(lru_cache.len(), 0);
let _ = lru_cache.insert(0, 0);
Expand All @@ -579,7 +606,7 @@ mod test {
let size = 10usize;
let time_to_live = Duration::from_millis(100);
let mut lru_cache =
super::LruCache::<usize, usize>::with_expiry_duration_and_capacity(time_to_live, size);
LruCache::<usize, usize>::with_expiry_duration_and_capacity(time_to_live, size);

for i in 0..1000 {
if i < size {
Expand Down Expand Up @@ -612,7 +639,7 @@ mod test {
let time_to_live = Duration::from_millis(100);

let mut lru_cache =
super::LruCache::<Temp, usize>::with_expiry_duration_and_capacity(time_to_live, size);
LruCache::<Temp, usize>::with_expiry_duration_and_capacity(time_to_live, size);

for i in 0..1000 {
if i < size {
Expand Down Expand Up @@ -753,6 +780,25 @@ mod test {
}
}

mod retain {
use super::*;

#[test]
fn it_removes_all_invalid_entries() {
let mut lru_cache = LruCache::<usize, usize>::with_capacity(4);
let _ = lru_cache.insert(2, 2);
let _ = lru_cache.insert(0, 0);
let _ = lru_cache.insert(3, 3);
let _ = lru_cache.insert(1, 1);

lru_cache.retain(|(_, &value)| value > 1);

let cached = lru_cache.peek_iter().collect::<Vec<_>>();

assert_eq!(cached, vec![(&3, &3), (&2, &2)]);
}
}

mod notify_iter {
use super::*;

Expand Down Expand Up @@ -839,7 +885,7 @@ mod test {
#[test]
fn it_yields_cached_entries_in_most_recently_used_order() {
let time_to_live = Duration::from_millis(500);
let mut lru_cache = super::LruCache::<usize, usize>::with_expiry_duration(time_to_live);
let mut lru_cache = LruCache::<usize, usize>::with_expiry_duration(time_to_live);

let _ = lru_cache.insert(1, 1);
let _ = lru_cache.insert(2, 2);
Expand All @@ -854,7 +900,7 @@ mod test {
#[test]
fn it_yields_only_unexpired_entries() {
let time_to_live = Duration::from_millis(500);
let mut lru_cache = super::LruCache::<usize, usize>::with_expiry_duration(time_to_live);
let mut lru_cache = LruCache::<usize, usize>::with_expiry_duration(time_to_live);

let _ = lru_cache.insert(1, 1);
let _ = lru_cache.insert(2, 2);
Expand All @@ -870,7 +916,7 @@ mod test {
#[test]
fn it_doesnt_modify_entry_update_time() {
let time_to_live = Duration::from_millis(500);
let mut lru_cache = super::LruCache::<usize, usize>::with_expiry_duration(time_to_live);
let mut lru_cache = LruCache::<usize, usize>::with_expiry_duration(time_to_live);

let _ = lru_cache.insert(1, 1);
let expected_time = lru_cache
Expand All @@ -895,7 +941,7 @@ mod test {
#[test]
fn update_time_check() {
let time_to_live = Duration::from_millis(500);
let mut lru_cache = super::LruCache::<usize, usize>::with_expiry_duration(time_to_live);
let mut lru_cache = LruCache::<usize, usize>::with_expiry_duration(time_to_live);

assert_eq!(lru_cache.len(), 0);
let _ = lru_cache.insert(0, 0);
Expand All @@ -911,9 +957,9 @@ mod test {

#[test]
fn deref_coercions() {
let mut lru_cache = super::LruCache::<String, usize>::with_capacity(1);
let mut lru_cache = LruCache::<String, usize>::with_capacity(1);
let _ = lru_cache.insert("foo".to_string(), 0);
assert_eq!(true, lru_cache.contains_key("foo"));
assert!(lru_cache.contains_key("foo"));
assert_eq!(Some(&0), lru_cache.get("foo"));
assert_eq!(Some(&mut 0), lru_cache.get_mut("foo"));
assert_eq!(Some(&0), lru_cache.peek("foo"));
Expand Down