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use core::convert::Infallible;
use std::collections::BTreeSet;
use serde::{Deserialize, Serialize};
use crate::{CmRDT, CvRDT};
/// A `GSet` is a grow-only set.
#[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub struct GSet<T: Ord> {
value: BTreeSet<T>,
}
impl<T: Ord> Default for GSet<T> {
fn default() -> Self {
GSet::new()
}
}
impl<T: Ord> From<GSet<T>> for BTreeSet<T> {
fn from(gset: GSet<T>) -> BTreeSet<T> {
gset.value
}
}
impl<T: Ord> CvRDT for GSet<T> {
type Validation = Infallible;
fn validate_merge(&self, _other: &Self) -> Result<(), Self::Validation> {
Ok(())
}
/// Merges another `GSet` into this one.
///
/// # Examples
///
/// ```rust
/// use crdts::{GSet, CvRDT, CmRDT};
/// let (mut a, mut b) = (GSet::new(), GSet::new());
/// a.insert(1);
/// b.insert(2);
/// a.merge(b);
/// assert!(a.contains(&1));
/// assert!(a.contains(&2));
/// ```
fn merge(&mut self, other: Self) {
other.value.into_iter().for_each(|e| self.insert(e))
}
}
impl<T: Ord> CmRDT for GSet<T> {
type Op = T;
type Validation = Infallible;
fn validate_op(&self, _op: &Self::Op) -> Result<(), Self::Validation> {
Ok(())
}
fn apply(&mut self, op: Self::Op) {
self.insert(op);
}
}
impl<T: Ord> GSet<T> {
/// Instantiates an empty `GSet`.
pub fn new() -> Self {
Self {
value: BTreeSet::new(),
}
}
/// Inserts an element into this `GSet`.
///
/// # Examples
///
/// ```rust
/// use crdts::GSet;
/// let mut a = GSet::new();
/// a.insert(1);
/// assert!(a.contains(&1));
/// ```
pub fn insert(&mut self, element: T) {
self.value.insert(element);
}
/// Returns `true` if the `GSet` contains the element.
///
/// # Examples
///
/// ```rust
/// use crdts::GSet;
/// let mut a = GSet::new();
/// a.insert(1);
/// assert!(a.contains(&1));
/// ```
pub fn contains(&self, element: &T) -> bool {
self.value.contains(element)
}
/// Returns the `BTreeSet` for this `GSet`.
///
/// # Examples
///
/// ```rust
/// use crdts::GSet;
/// use std::collections::BTreeSet;
/// let mut a = GSet::new();
/// let mut b = BTreeSet::new();
/// for i in 1..10 {
/// a.insert(i);
/// b.insert(i);
/// }
///
/// assert_eq!(a.read(), b);
/// ```
pub fn read(&self) -> BTreeSet<T>
where
T: Clone,
{
self.value.clone()
}
}