Struct elsa::sync::FrozenMap

pub struct FrozenMap<K, V> { /* private fields */ }

Append-only threadsafe version of std::collections::HashMap where insertion does not require mutable access

Implementations

impl<K, V> FrozenMap<K, V>

pub fn new() -> Self

impl<K: Eq + Hash, V: StableDeref> FrozenMap<K, V>

pub fn insert(&self, k: K, v: V) -> &V::Target

If the key exists in the map, returns a reference to the corresponding value, otherwise inserts a new entry in the map for that key and returns a reference to the given value.

Existing values are never overwritten.

The key may be any borrowed form of the map’s key type, but Hash and Eq on the borrowed form must match those for the key type.

Examples

use elsa::sync::FrozenMap;

let map = FrozenMap::new();
assert_eq!(map.insert(1, Box::new("a")), &"a");
assert_eq!(map.insert(1, Box::new("b")), &"a");

pub fn insert_with(&self, k: K, f: impl FnOnce() -> V) -> &V::Target

If the key exists in the map, returns a reference to the corresponding value, otherwise inserts a new entry in the map for that key and the value returned by the creation function, and returns a reference to the generated value.

Existing values are never overwritten.

The key may be any borrowed form of the map’s key type, but Hash and Eq on the borrowed form must match those for the key type.

Note that the write lock is held for the duration of this function’s execution, even while the value creation function is executing (if needed). This will block any concurrent get or insert calls.

Examples

use elsa::sync::FrozenMap;

let map = FrozenMap::new();
assert_eq!(map.insert_with(1, || Box::new("a")), &"a");
assert_eq!(map.insert_with(1, || unreachable!()), &"a");

pub fn insert_with_key(&self, k: K, f: impl FnOnce(&K) -> V) -> &V::Target

If the key exists in the map, returns a reference to the corresponding value, otherwise inserts a new entry in the map for that key and the value returned by the creation function, and returns a reference to the generated value.

Existing values are never overwritten.

The key may be any borrowed form of the map’s key type, but Hash and Eq on the borrowed form must match those for the key type.

Note that the write lock is held for the duration of this function’s execution, even while the value creation function is executing (if needed). This will block any concurrent get or insert calls.

Examples

use elsa::sync::FrozenMap;

let map = FrozenMap::new();
assert_eq!(map.insert_with_key(1, |_| Box::new("a")), &"a");
assert_eq!(map.insert_with_key(1, |_| unreachable!()), &"a");

pub fn get<Q>(&self, k: &Q) -> Option<&V::Target>where K: Borrow<Q>, Q: Hash + Eq + ?Sized,

Returns a reference to the value corresponding to the key.

The key may be any borrowed form of the map’s key type, but Hash and Eq on the borrowed form must match those for the key type.

Examples

use elsa::sync::FrozenMap;

let map = FrozenMap::new();
map.insert(1, Box::new("a"));
assert_eq!(map.get(&1), Some(&"a"));
assert_eq!(map.get(&2), None);

pub fn map_get<Q, T, F>(&self, k: &Q, f: F) -> Option<T>where K: Borrow<Q>, Q: Hash + Eq + ?Sized, F: FnOnce(&V) -> T,

Applies a function to the owner of the value corresponding to the key (if any).

The key may be any borrowed form of the map’s key type, but Hash and Eq on the borrowed form must match those for the key type.

Examples

use elsa::sync::FrozenMap;

let map = FrozenMap::new();
map.insert(1, Box::new("a"));
assert_eq!(map.map_get(&1, Clone::clone), Some(Box::new("a")));
assert_eq!(map.map_get(&2, Clone::clone), None);

impl<K, V> FrozenMap<K, V>

pub fn into_tuple_vec(self) -> Vec<(K, V)>

Collects the contents of this map into a vector of tuples.

The order of the entries is as if iterating a HashMap (stochastic).

Examples

use elsa::sync::FrozenMap;

let map = FrozenMap::new();
map.insert(1, Box::new("a"));
map.insert(2, Box::new("b"));
let mut tuple_vec = map.into_tuple_vec();
tuple_vec.sort();

assert_eq!(tuple_vec, vec![(1, Box::new("a")), (2, Box::new("b"))]);

pub fn len(&self) -> usize

Examples

use elsa::sync::FrozenMap;

let map = FrozenMap::new();
assert_eq!(map.len(), 0);
map.insert(1, Box::new("a"));
assert_eq!(map.len(), 1);

pub fn is_empty(&self) -> bool

Examples

use elsa::sync::FrozenMap;

let map = FrozenMap::new();
assert_eq!(map.is_empty(), true);
map.insert(1, Box::new("a"));
assert_eq!(map.is_empty(), false);

impl<K: Clone, V> FrozenMap<K, V>

pub fn keys_cloned(&self) -> Vec<K>

impl<K: Eq + Hash, V: Copy> FrozenMap<K, V>

pub fn get_copy<Q>(&self, k: &Q) -> Option<V>where K: Borrow<Q>, Q: Hash + Eq + ?Sized,

Returns a copy of the value corresponding to the key.

The key may be any borrowed form of the map’s key type, but Hash and Eq on the borrowed form must match those for the key type.

Examples

use elsa::sync::FrozenMap;

let map = FrozenMap::new();
map.get_copy_or_insert(1, 6);
assert_eq!(map.get_copy(&1), Some(6));
assert_eq!(map.get_copy(&2), None);

pub fn get_copy_or_insert(&self, k: K, v: V) -> V

If the key exists in the map, returns a reference to the corresponding value, otherwise inserts a new entry in the map for that key and returns a reference to the given value.

Existing values are never overwritten.

The key may be any borrowed form of the map’s key type, but Hash and Eq on the borrowed form must match those for the key type.

Examples

use elsa::sync::FrozenMap;

let map = FrozenMap::new();
assert_eq!(map.get_copy_or_insert(1, 6), 6);
assert_eq!(map.get_copy_or_insert(1, 12), 6);

pub fn get_copy_or_insert_with(&self, k: K, f: impl FnOnce() -> V) -> V

If the key exists in the map, returns a reference to the corresponding value, otherwise inserts a new entry in the map for that key and the value returned by the creation function, and returns a reference to the generated value.

Existing values are never overwritten.

The key may be any borrowed form of the map’s key type, but Hash and Eq on the borrowed form must match those for the key type.

Note that the write lock is held for the duration of this function’s execution, even while the value creation function is executing (if needed). This will block any concurrent get or insert calls.

Examples

use elsa::sync::FrozenMap;

let map = FrozenMap::new();
assert_eq!(map.get_copy_or_insert_with(1, || 6), 6);
assert_eq!(map.get_copy_or_insert_with(1, || unreachable!()), 6);

pub fn get_copy_or_insert_with_key(&self, k: K, f: impl FnOnce(&K) -> V) -> V

If the key exists in the map, returns a reference to the corresponding value, otherwise inserts a new entry in the map for that key and the value returned by the creation function, and returns a reference to the generated value.

Existing values are never overwritten.

The key may be any borrowed form of the map’s key type, but Hash and Eq on the borrowed form must match those for the key type.

Note that the write lock is held for the duration of this function’s execution, even while the value creation function is executing (if needed). This will block any concurrent get or insert calls.

Examples

use elsa::sync::FrozenMap;

let map = FrozenMap::new();
assert_eq!(map.get_copy_or_insert_with_key(1, |_| 6), 6);
assert_eq!(map.get_copy_or_insert_with_key(1, |_| unreachable!()), 6);

Trait Implementations

impl<K, V> AsMut<HashMap<K, V, RandomState>> for FrozenMap<K, V>

fn as_mut(&mut self) -> &mut HashMap<K, V>

Get mutable access to the underlying HashMap.

This is safe, as it requires a &mut self, ensuring nothing is using the ‘frozen’ contents.

impl<K: Clone, V: Clone> Clone for FrozenMap<K, V>

fn clone(&self) -> Self

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<K: Debug, V: Debug> Debug for FrozenMap<K, V>

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

Formats the value using the given formatter.

impl<K, V> Default for FrozenMap<K, V>

fn default() -> Self

Returns the “default value” for a type.

impl<K: Eq + Hash, V: PartialEq> PartialEq<FrozenMap<K, V>> for FrozenMap<K, V>

fn eq(&self, other: &Self) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.