pub struct VacantEntry<'a, K: 'a + Eq + Hash, V: 'a> { /* fields omitted */ }
A view into a vacant entry in a Cache
.
It is part of the Entry
enum.
Gets a reference to the key that would be used when inserting a value
through the VacantEntry
.
use cache_2q::{Cache, Entry};
let mut cache: Cache<&str, u32> = Cache::new(8);
if let Entry::Vacant(v) = cache.entry("poneyland") {
assert_eq!(v.key(), &"poneyland");
} else {
panic!("Entry should be vacant");
}
Take ownership of the key.
use cache_2q::{Cache, Entry};
let mut cache: Cache<String, u32> = Cache::new(8);
if let Entry::Vacant(v) = cache.entry("poneyland".into()) {
assert_eq!(v.into_key(), "poneyland".to_string());
} else {
panic!("Entry should be vacant");
}
If this vacant entry is remembered
Keys are remembered after they are evicted from the cache. If this entry is remembered,
if inserted, it will be insert to a frequent
list, instead of the usual recent
list
use cache_2q::{Cache, Entry};
let mut cache: Cache<&str, u32> = Cache::new(1);
if let Entry::Vacant(v) = cache.entry("poneyland") {
assert!(!v.is_remembered());
} else {
panic!("Entry should be vacant");
}
cache.insert("poneyland", 0);
cache.insert("other", 1);
if let Entry::Vacant(v) = cache.entry("poneyland") {
assert!(v.is_remembered());
v.insert(0);
} else {
panic!("Entry should be vacant");
}
Sets the value of the entry with the VacantEntry's key,
and returns a mutable reference to it.
use cache_2q::{Cache, Entry};
let mut cache: Cache<&str, u32> = Cache::new(8);
if let Entry::Vacant(o) = cache.entry("poneyland") {
o.insert(37);
} else {
panic!("Entry should be vacant");
}
assert_eq!(*cache.get("poneyland").unwrap(), 37);
Formats the value using the given formatter. Read more