Struct TwoPSet 

pub struct TwoPSet<T: Ord + Clone> { /* private fields */ }

A two-phase set (2P-Set).

Elements can be added and removed, but once removed, they cannot be re-added. This is implemented with two G-Sets: one for additions and one for removals (tombstones).

Example

use crdt_kit::prelude::*;

let mut s1 = TwoPSet::new();
s1.insert("apple");
s1.insert("banana");
s1.remove(&"banana");

assert!(s1.contains(&"apple"));
assert!(!s1.contains(&"banana")); // removed

let mut s2 = TwoPSet::new();
s2.insert("banana"); // trying to re-add on another replica

s1.merge(&s2);
assert!(!s1.contains(&"banana")); // still removed (tombstone wins)

Implementations

impl<T: Ord + Clone> TwoPSet<T>

pub fn new() -> Self

Create a new empty 2P-Set.

pub fn insert(&mut self, value: T) -> bool

Insert an element.

Returns true if the element was newly added (not previously removed). If the element was already removed, it cannot be re-added and this returns false.

pub fn remove(&mut self, value: &T) -> bool

Remove an element.

The element must have been added first. Once removed, it can never be re-added. Returns true if the element was present and is now removed.

pub fn contains(&self, value: &T) -> bool

Check if the set contains an element (added and not removed).

pub fn len(&self) -> usize

Get the number of active elements (added minus removed).

pub fn is_empty(&self) -> bool

Check if the set has no active elements.

pub fn iter(&self) -> impl Iterator<Item = &T>

Iterate over active elements (added and not removed).

Trait Implementations

impl<T: Clone + Ord + Clone> Clone for TwoPSet<T>

fn clone(&self) -> TwoPSet<T>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Ord + Clone> Crdt for TwoPSet<T>

fn merge(&mut self, other: &Self)

Merge another replica’s state into this one.

impl<T: Debug + Ord + Clone> Debug for TwoPSet<T>

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

Formats the value using the given formatter.

impl<T: Ord + Clone> Default for TwoPSet<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T: Ord + Clone> IntoIterator for TwoPSet<T>

type Item = T

The type of the elements being iterated over.

type IntoIter = IntoIter<T>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<T: PartialEq + Ord + Clone> PartialEq for TwoPSet<T>

fn eq(&self, other: &TwoPSet<T>) -> bool

Tests for self and other values to be equal, and is used by ==.

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

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

impl<T: Eq + Ord + Clone> Eq for TwoPSet<T>

impl<T: Ord + Clone> StructuralPartialEq for TwoPSet<T>