Struct crdts::map::Map

pub struct Map<K: Ord, V: Val<A>, A: Ord + Hash> { /* private fields */ }

Map CRDT - Supports Composition of CRDT’s with reset-remove semantics.

Reset-remove means that if one replica removes an entry while another actor concurrently edits that entry, once we sync these two maps, we will see that the entry is still in the map but all edits seen by the removing actor will be gone.

See examples/reset_remove.rs for an example of reset-remove semantics in action.

Implementations

impl<K: Ord, V: Val<A>, A: Ord + Hash + Clone> Map<K, V, A>

pub fn new() -> Self

Constructs an empty Map

pub fn is_empty(&self) -> ReadCtx<bool, A>

Returns true if the map has no entries, false otherwise

pub fn len(&self) -> ReadCtx<usize, A>

Returns the number of entries in the Map

pub fn get(&self, key: &K) -> ReadCtx<Option<V>, A>

Retrieve value stored under a key

pub fn update<F>(&self, key: impl Into<K>, ctx: AddCtx<A>, f: F) -> Op<K, V, A>where F: FnOnce(&V, AddCtx<A>) -> V::Op,

Update a value under some key.

If the key is not present in the map, the updater will be given the result of V::default(). The default value is used to ensure eventual consistency since our Map’s values are CRDTs themselves.

The impl Into<K> bound provides a nice way of providing an input key that can easily convert to the Map’s key. For example, we can call this function with "hello": &str and it can be converted to String.

pub fn rm(&self, key: impl Into<K>, ctx: RmCtx<A>) -> Op<K, V, A>

Remove an entry from the Map

The impl Into<K> bound provides a nice way of providing an input key that can easily convert to the Map’s key. For example, we can call this function with "hello": &str and it can be converted to String.

pub fn read_ctx(&self) -> ReadCtx<(), A>

Retrieve the current read context

pub fn keys(&self) -> impl Iterator<Item = ReadCtx<&K, A>>

Gets an iterator over the keys of the Map.

Examples

use crdts::Map;
use crdts::MVReg;
use crdts::CmRDT;

type Actor = &'static str;
type Key = &'static str;

let actor = "actor";

let mut map: Map<i32, MVReg<Key, Actor>, Actor> = Map::new();

let add_ctx = map.read_ctx().derive_add_ctx(actor);
map.apply(map.update(100, add_ctx, |v, a| v.write("foo", a)));

let add_ctx = map.read_ctx().derive_add_ctx(actor);
map.apply(map.update(50, add_ctx, |v, a| v.write("bar", a)));

let add_ctx = map.read_ctx().derive_add_ctx(actor);
map.apply(map.update(200, add_ctx, |v, a| v.write("baz", a)));


let mut keys: Vec<_> = map.keys().map(|key_ctx| *key_ctx.val).collect();

keys.sort();

assert_eq!(keys, &[50, 100, 200]);

pub fn values(&self) -> impl Iterator<Item = ReadCtx<&V, A>>

Gets an iterator over the values of the Map.

Examples

use crdts::Map;
use crdts::MVReg;
use crdts::CmRDT;

type Actor = &'static str;
type Key = &'static str;

let actor = "actor";

let mut map: Map<i32, MVReg<Key, Actor>, Actor> = Map::new();

let add_ctx = map.read_ctx().derive_add_ctx(actor);
map.apply(map.update(100, add_ctx, |v, a| v.write("foo", a)));

let add_ctx = map.read_ctx().derive_add_ctx(actor);
map.apply(map.update(50, add_ctx, |v, a| v.write("bar", a)));

let add_ctx = map.read_ctx().derive_add_ctx(actor);
map.apply(map.update(200, add_ctx, |v, a| v.write("baz", a)));


let mut values: Vec<_> = map
    .values()
    .map(|val_ctx| val_ctx.val.read().val[0])
    .collect();

values.sort();

assert_eq!(values, &["bar", "baz", "foo"]);

pub fn iter(&self) -> impl Iterator<Item = ReadCtx<(&K, &V), A>>

Gets an iterator over the entries of the Map.

Examples

use crdts::Map;
use crdts::MVReg;
use crdts::CmRDT;

type Actor = &'static str;
type Key = &'static str;

let actor = "actor";

let mut map: Map<i32, MVReg<Key, Actor>, Actor> = Map::new();

let add_ctx = map.read_ctx().derive_add_ctx(actor);
map.apply(map.update(100, add_ctx, |v, a| v.write("foo", a)));

let add_ctx = map.read_ctx().derive_add_ctx(actor);
map.apply(map.update(50, add_ctx, |v, a| v.write("bar", a)));

let add_ctx = map.read_ctx().derive_add_ctx(actor);
map.apply(map.update(200, add_ctx, |v, a| v.write("baz", a)));


let mut items: Vec<_> = map
    .iter()
    .map(|item_ctx| (*item_ctx.val.0, item_ctx.val.1.read().val[0]))
    .collect();

items.sort();

assert_eq!(items, &[(50, "bar"), (100, "foo"), (200, "baz")]);

Trait Implementations

impl<K: Clone + Ord, V: Clone + Val<A>, A: Clone + Ord + Hash> Clone for Map<K, V, A>

fn clone(&self) -> Map<K, V, A>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<K: Ord, V: Val<A> + Debug, A: Ord + Hash + Clone + Debug> CmRDT for Map<K, V, A>

type Op = Op<K, V, A>

Op defines a mutation to the CRDT. As long as Op’s from one actor are replayed in exactly the same order they were generated by that actor, the CRDT will converge. In other words, we must have a total ordering on each actors operations, while requiring only a partial order over all ops. E.g.

type Validation = CmRDTValidation<V, A>

The validation error returned by validate_op.

fn validate_op(&self, op: &Self::Op) -> Result<(), Self::Validation>

Some CRDT’s have stricter requirements on how they must be used. To avoid violating these requirements, CRDT’s provide an interface to optionally validate op’s before they are applied.

fn apply(&mut self, op: Self::Op)

Apply an Op to the CRDT

impl<K: Ord + Clone + Debug, V: Val<A> + CvRDT + Debug, A: Ord + Hash + Clone + Debug> CvRDT for Map<K, V, A>

type Validation = CvRDTValidation<K, V, A>

The validation error returned by validate_merge.

fn validate_merge(&self, other: &Self) -> Result<(), Self::Validation>

Some CRDT’s have stricter requirements on how they must be used. To avoid violating these requirements, CRDT’s provide an interface to optionally validate merge compatibility before attempting to merge.

fn merge(&mut self, other: Self)

Merge the given CRDT into the current CRDT.

impl<K: Debug + Ord, V: Debug + Val<A>, A: Debug + Ord + Hash> Debug for Map<K, V, A>

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

Formats the value using the given formatter.

impl<K: Ord, V: Val<A>, A: Ord + Hash> Default for Map<K, V, A>

fn default() -> Self

Returns the “default value” for a type.

impl<'de, K, V, A> Deserialize<'de> for Map<K, V, A>where K: Deserialize<'de> + Ord, V: Deserialize<'de> + Val<A>, A: Deserialize<'de> + Ord + Hash,

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

Deserialize this value from the given Serde deserializer.

impl<K: PartialEq + Ord, V: PartialEq + Val<A>, A: PartialEq + Ord + Hash> PartialEq<Map<K, V, A>> for Map<K, V, A>

fn eq(&self, other: &Map<K, V, A>) -> 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.

impl<K: Ord, V: Val<A>, A: Ord + Hash> ResetRemove<A> for Map<K, V, A>

fn reset_remove(&mut self, clock: &VClock<A>)

Remove data that is strictly smaller than this clock

impl<K, V, A> Serialize for Map<K, V, A>where K: Serialize + Ord, V: Serialize + Val<A>, A: Serialize + Ord + Hash,

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

Serialize this value into the given Serde serializer.

impl<K: Eq + Ord, V: Eq + Val<A>, A: Eq + Ord + Hash> Eq for Map<K, V, A>

impl<K: Ord, V: Val<A>, A: Ord + Hash> StructuralEq for Map<K, V, A>

impl<K: Ord, V: Val<A>, A: Ord + Hash> StructuralPartialEq for Map<K, V, A>