Enum cow_hashmap::Entry

pub enum Entry<K: Clone, V, S> {
    Occupied(OccupiedEntry<K, V, S>),
    Vacant(VacantEntry<K, V, S>),
}

A view into a single entry in a map, which may either be vacant or occupied.

This enum is constructed from the entry method on [HashMap].

Variants

Occupied(OccupiedEntry<K, V, S>)

An occupied entry.

Vacant(VacantEntry<K, V, S>)

A vacant entry.

Implementations

impl<K: Clone, V, S> Entry<K, V, S>

pub fn or_insert(self, default: V) -> Arc<V>

where K: Hash, S: BuildHasher,

Ensures a value is in the entry by inserting the default if empty, and returns a mutable reference to the value in the entry.

Examples

use cow_hashmap::CowHashMap as HashMap;
use std::sync::Arc;

let mut map: HashMap<&str, u32> = HashMap::new();

map.entry("poneyland").or_insert(3);
assert_eq!(map.get("poneyland").unwrap(), Arc::new(3));

*map.entry("poneyland").or_insert(10) *= 2;
assert_eq!(map.get("poneyland").unwrap(), Arc::new(6));

pub fn or_insert_mut(self, default: V) -> CowValueGuard<V>

where K: Hash, S: BuildHasher, V: Clone,

Ensures a value is in the entry by inserting the default if empty, and returns a mutable reference to the value in the entry.

Examples

use cow_hashmap::CowHashMap as HashMap;
use std::sync::Arc;

let mut map: HashMap<&str, u32> = HashMap::new();

map.entry("poneyland").or_insert(3);
assert_eq!(map.get("poneyland").unwrap(), Arc::new(3));

*map.entry("poneyland").or_insert(10) *= 2;
assert_eq!(map.get("poneyland").unwrap(), Arc::new(6));

pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> Arc<V>

where K: Hash, S: BuildHasher,

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.

Examples

use cow_hashmap::CowHashMap as HashMap;
use std::sync::Arc;

let mut map = HashMap::new();
let value = "hoho";

map.entry("poneyland").or_insert_with(|| value);

assert_eq!(map.get("poneyland").unwrap(), Arc::new("hoho"));

pub fn or_insert_with_mut<F: FnOnce() -> V>( self, default: F, ) -> CowValueGuard<V>

where K: Hash, S: BuildHasher, V: Clone,

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.

Examples

use cow_hashmap::CowHashMap as HashMap;
use std::sync::Arc;

let mut map = HashMap::new();
let value = "hoho";

map.entry("poneyland").or_insert_with(|| value);

assert_eq!(map.get("poneyland").unwrap(), Arc::new("hoho"));

pub fn or_try_insert_with<F: FnOnce() -> Option<V>>( self, f: F, ) -> Option<Arc<V>>

where K: Hash, S: BuildHasher,

Ensures a value is in the entry by trying to insert the result of function if empty, and returns a mutable reference to the value in the entry if that function was successful.

Examples

use cow_hashmap::CowHashMap as HashMap;
use std::sync::Arc;

let mut map = HashMap::new();
let value = "hoho";

map.entry("poneyland").or_try_insert_with(|| Some(value)).unwrap();

assert_eq!(map.get("poneyland").unwrap(), Arc::new("hoho"));

pub fn or_try_insert_with_mut<F: FnOnce() -> Option<V>>( self, f: F, ) -> Option<CowValueGuard<V>>

where K: Hash, S: BuildHasher, V: Clone,

Ensures a value is in the entry by trying to insert the result of function if empty, and returns a mutable reference to the value in the entry if that function was successful.

Examples

use cow_hashmap::CowHashMap as HashMap;
use std::sync::Arc;

let mut map = HashMap::new();
let value = "hoho";

map.entry("poneyland").or_try_insert_with(|| Some(value)).unwrap();

assert_eq!(map.get("poneyland").unwrap(), Arc::new("hoho"));

pub fn or_insert_with_key<F: FnOnce(&K) -> V>(self, default: F) -> Arc<V>

where K: Hash, S: BuildHasher,

Ensures a value is in the entry by inserting, if empty, the result of the default function. This method allows for generating key-derived values for insertion by providing the default function a reference to the key that was moved during the .entry(key) method call.

The reference to the moved key is provided so that cloning or copying the key is unnecessary, unlike with .or_insert_with(|| ... ).

Examples

use cow_hashmap::CowHashMap as HashMap;
use std::sync::Arc;

let mut map: HashMap<&str, usize> = HashMap::new();

map.entry("poneyland").or_insert_with_key(|key| key.chars().count());

assert_eq!(map.get("poneyland").unwrap(), Arc::new(9));

pub fn or_insert_with_key_mut<F: FnOnce(&K) -> V>( self, default: F, ) -> CowValueGuard<V>

where K: Hash, S: BuildHasher, V: Clone,

Ensures a value is in the entry by inserting, if empty, the result of the default function. This method allows for generating key-derived values for insertion by providing the default function a reference to the key that was moved during the .entry(key) method call.

The reference to the moved key is provided so that cloning or copying the key is unnecessary, unlike with .or_insert_with(|| ... ).

Examples

use cow_hashmap::CowHashMap as HashMap;
use std::sync::Arc;

let mut map: HashMap<&str, usize> = HashMap::new();

map.entry("poneyland").or_insert_with_key(|key| key.chars().count());

assert_eq!(map.get("poneyland").unwrap(), Arc::new(9));

pub fn key(&self) -> &K

Returns a reference to this entry’s key.

Examples

use cow_hashmap::CowHashMap as HashMap;

let mut map: HashMap<&str, u32> = HashMap::new();
assert_eq!(map.entry("poneyland").key(), &"poneyland");

pub fn and_modify<F>(self, f: F) -> Self

where F: FnOnce(CowValueGuard<V>), V: Clone,

Provides in-place mutable access to an occupied entry before any potential inserts into the map.

Examples

use cow_hashmap::CowHashMap as HashMap;

let mut map: HashMap<&str, u32> = HashMap::new();

map.entry("poneyland")
   .and_modify(|mut e| { *e += 1 })
   .or_insert(42);
assert_eq!(*map.get("poneyland").unwrap(), 42);

map.entry("poneyland")
   .and_modify(|mut e| { *e += 1 })
   .or_insert(42);
assert_eq!(*map.get("poneyland").unwrap(), 43);

impl<K: Clone, V: Default, S> Entry<K, V, S>

pub fn or_default(self) -> Arc<V>

where K: Hash, S: BuildHasher,

Ensures a value is in the entry by inserting the default value if empty, and returns a mutable reference to the value in the entry.

Examples

use cow_hashmap::CowHashMap as HashMap;
use std::sync::Arc;

let mut map: HashMap<&str, Option<u32>> = HashMap::new();
map.entry("poneyland").or_default();

assert_eq!(map.get("poneyland").unwrap(), Arc::new(None));

pub fn or_default_mut(self) -> CowValueGuard<V>

where K: Hash, S: BuildHasher, V: Clone,

Ensures a value is in the entry by inserting the default value if empty, and returns a mutable reference to the value in the entry.

Examples

use cow_hashmap::CowHashMap as HashMap;
use std::sync::Arc;

let mut map: HashMap<&str, Option<u32>> = HashMap::new();
map.entry("poneyland").or_default();

assert_eq!(map.get("poneyland").unwrap(), Arc::new(None));

Trait Implementations

impl<K: Clone + Debug, V: Debug, S> Debug for Entry<K, V, S>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.