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SyncHashMap

Struct SyncHashMap 

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pub struct SyncHashMap<K: Eq + Hash, V> { /* private fields */ }
Expand description

A concurrent HashMap with a Go sync.Map-style read/dirty architecture:

  • read: an immutable snapshot, atomically published. get / iter / Index read it lock-free.
  • dirty: the canonical, mutable map, guarded by lock.

Every slot is an Arc<Entry<V>> shared between the snapshot and dirty. The entry holds an atomic pointer to the value, so updating an existing key swaps the pointer in place (O(1)) — no snapshot rebuild — and readers always see the latest value. New keys and removals are published lazily (tracked by the amended flag). Snapshots and retired values are kept alive until the map is dropped, so references returned by get stay valid.

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impl<K, V> SyncHashMap<K, V>
where K: Eq + Hash,

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pub fn new_arc() -> Arc<Self>

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pub fn new() -> Self

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pub fn with_capacity(capacity: usize) -> Self

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pub fn with_map(map: Map<K, V>) -> Self

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pub fn insert(&self, k: K, v: V) -> Option<V>
where K: Clone, V: Clone,

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pub fn insert_mut(&mut self, k: K, v: V) -> Option<V>
where K: Clone, V: Clone,

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pub fn remove(&self, k: &K) -> Option<V>
where K: Clone, V: Clone,

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pub fn remove_mut(&mut self, k: &K) -> Option<V>
where K: Clone, V: Clone,

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pub fn len(&self) -> usize

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pub fn is_empty(&self) -> bool

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pub fn clear(&self)
where K: Clone,

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pub fn clear_mut(&mut self)
where K: Clone,

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pub fn shrink_to_fit(&self)

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pub fn shrink_to_fit_mut(&mut self)

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pub fn from(map: Map<K, V>) -> Self
where K: Eq + Hash,

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pub fn get<Q>(&self, k: &Q) -> Option<&V>
where K: Borrow<Q> + Clone, 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.

Reads are lock-free: the value is served from the immutable read snapshot through a shared entry, so updates are visible immediately. If the key was added to dirty since the last snapshot was published, a fresh snapshot is published first.

§Examples
use dark_std::sync::{SyncHashMap};

let mut map = SyncHashMap::new();
map.insert_mut(1, "a");
assert_eq!(*map.get(&1).unwrap(), "a");
assert_eq!(map.get(&2).is_none(), true);
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pub fn get_mut(&self, k: &K) -> Option<HashMapRefMut<'_, K, V>>
where K: Hash + Eq + Clone, V: Clone,

Returns a mutable handle to the value for k, implemented with copy-on-write: the value is cloned, the handle mutates the clone, and the result is swapped back into the shared entry (O(1)) when the handle is dropped. Concurrent readers may observe the pre-mutation value until the handle is dropped.

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pub fn contains_key(&self, x: &K) -> bool
where K: PartialEq,

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pub fn iter(&self) -> Iter<'_, K, V>
where K: Clone,

Iterate over the current contents. A fresh snapshot is published first, so all entries written so far are visible.

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pub fn iter_mut(&self) -> IterMut<'_, K, V>
where K: Clone, V: Clone,

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pub fn into_iter(self) -> MapIntoIter<K, V>

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pub fn into_inner(self) -> Map<K, V>

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impl<K: Clone + Eq + Hash, V: Clone> Clone for SyncHashMap<K, V>

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fn clone(&self) -> Self

Returns a duplicate of the value. Read more
1.0.0 (const: unstable) · Source§

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

Performs copy-assignment from source. Read more
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impl<K, V> Debug for SyncHashMap<K, V>
where K: Eq + Hash + Debug, V: Debug,

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

Formats the value using the given formatter. Read more
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impl<K: Eq + Hash, V> Default for SyncHashMap<K, V>

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fn default() -> Self

Returns the “default value” for a type. Read more
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impl<'de, K, V> Deserialize<'de> for SyncHashMap<K, V>
where K: Eq + Hash + Deserialize<'de>, V: Deserialize<'de>,

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fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer. Read more
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impl<K, V> Display for SyncHashMap<K, V>
where K: Eq + Hash + Display, V: Display,

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

Formats the value using the given formatter. Read more
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impl<K: Eq + Hash, V> From<HashMap<K, V>> for SyncHashMap<K, V>

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fn from(arg: Map<K, V>) -> Self

Converts to this type from the input type.
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impl<K, V> Index<&K> for SyncHashMap<K, V>
where K: Eq + Hash + Clone,

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type Output = V

The returned type after indexing.
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fn index(&self, index: &K) -> &Self::Output

Performs the indexing (container[index]) operation. Read more
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impl<'a, K, V> IntoIterator for &'a SyncHashMap<K, V>
where K: Eq + Hash + Clone,

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type Item = (&'a K, &'a V)

The type of the elements being iterated over.
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type IntoIter = Iter<'a, K, V>

Which kind of iterator are we turning this into?
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fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value. Read more
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impl<K, V> IntoIterator for SyncHashMap<K, V>
where K: Eq + Hash,

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type Item = (K, V)

The type of the elements being iterated over.
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type IntoIter = IntoIter<K, V>

Which kind of iterator are we turning this into?
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fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value. Read more
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impl<K: Eq + Hash, V> Send for SyncHashMap<K, V>

Safety: dirty is only ever accessed under lock; the read snapshot is immutable once published; values behind entries are immutable once published and swapped out atomically; retired values and retired snapshots are kept alive until the map is dropped, so references derived from get remain valid for the lifetime of &self.

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impl<K, V> Serialize for SyncHashMap<K, V>
where K: Eq + Hash + Serialize, V: Serialize,

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fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where S: Serializer,

Serialize this value into the given Serde serializer. Read more
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impl<K: Eq + Hash, V> Sync for SyncHashMap<K, V>

Auto Trait Implementations§

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impl<K, V> !Freeze for SyncHashMap<K, V>

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impl<K, V> !RefUnwindSafe for SyncHashMap<K, V>

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impl<K, V> Unpin for SyncHashMap<K, V>
where UnsafeCell<HashMap<K, Arc<Entry<V>>>>: Unpin, AtomicSnapshot<HashMap<K, Arc<Entry<V>>>>: Unpin, Retired<V>: Unpin,

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impl<K, V> UnsafeUnpin for SyncHashMap<K, V>
where UnsafeCell<HashMap<K, Arc<Entry<V>>>>: UnsafeUnpin, AtomicSnapshot<HashMap<K, Arc<Entry<V>>>>: UnsafeUnpin, Retired<V>: UnsafeUnpin,

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impl<K, V> UnwindSafe for SyncHashMap<K, V>
where UnsafeCell<HashMap<K, Arc<Entry<V>>>>: UnwindSafe, AtomicSnapshot<HashMap<K, Arc<Entry<V>>>>: UnwindSafe, Retired<V>: UnwindSafe,

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> CloneToUninit for T
where T: Clone,

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unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dest. Read more
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impl<T> DeserializeOwned for T
where T: for<'de> Deserialize<'de>,

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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T> ToString for T
where T: Display + ?Sized,

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fn to_string(&self) -> String

Converts the given value to a String. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.