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use crate::Diff;
use serde::Deserialize;
use serde::Serialize;
use std::collections::HashSet;
use std::fmt::Debug;
use std::fmt::Formatter;
use std::hash::Hash;
use std::iter::empty;
#[derive(Clone, PartialEq, Serialize, Deserialize)]
pub struct DiffHashSet<T: Diff>(#[serde(skip_serializing_if = "Option::is_none")] pub Option<Vec<InnerValue<T>>>);
#[derive(Clone, PartialEq, Serialize, Deserialize)]
#[serde(untagged)]
pub enum InnerValue<T: Diff> {
Add(<T as Diff>::Type),
Remove { remove: <T as Diff>::Type },
}
impl<T> Diff for HashSet<T>
where
T: Debug + Clone + PartialEq + Eq + Diff + Hash + for<'de> Deserialize<'de> + Serialize,
{
type Type = DiffHashSet<T>;
fn diff(&self, other: &Self) -> crate::Result<Self::Type> {
Ok(DiffHashSet(if self == other {
None
} else {
let mut val_diffs: Vec<InnerValue<T>> = vec![];
for add in other.difference(self) {
let add = add.clone().into_diff()?;
val_diffs.push(InnerValue::Add(add));
}
for remove in self.difference(other) {
let remove = remove.clone().into_diff()?;
val_diffs.push(InnerValue::Remove { remove });
}
Some(val_diffs)
}))
}
fn merge(&self, diff: Self::Type) -> crate::Result<Self> {
match diff.0 {
None => Ok(self.clone()),
Some(val_diffs) => {
let mut new: Self = self.clone();
for val_diff in val_diffs {
match val_diff {
InnerValue::Add(val) => {
new.insert(<T>::from_diff(val)?);
}
InnerValue::Remove { remove } => {
new.remove(&(<T>::from_diff(remove)?));
}
}
}
Ok(new)
}
}
}
fn into_diff(self) -> crate::Result<Self::Type> {
Ok(DiffHashSet(if self.is_empty() {
None
} else {
let mut diffs: Vec<InnerValue<T>> = vec![];
for val in self {
diffs.push(InnerValue::Add(val.into_diff()?));
}
Some(diffs)
}))
}
fn from_diff(diff: Self::Type) -> crate::Result<Self> {
let mut set = Self::new();
if let Some(vals) = diff.0 {
for val in vals {
match val {
InnerValue::Add(val) => {
set.insert(<T>::from_diff(val)?);
}
InnerValue::Remove { remove } => {
let val = <T>::from_diff(remove)?;
set.remove(&val);
}
}
}
}
Ok(set)
}
}
impl<T> Debug for DiffHashSet<T>
where
T: Debug + Diff,
{
fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
write!(f, "DiffHashSet")?;
let mut buf = f.debug_list();
if let Some(d) = &self.0 {
buf.entries(d.iter());
} else {
buf.entries(empty::<Vec<InnerValue<T>>>());
}
buf.finish()
}
}
impl<T> Debug for InnerValue<T>
where
T: Debug + Diff,
{
fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
match &self {
Self::Add(val) => f.debug_tuple("Add").field(val).finish(),
Self::Remove { remove } => f.debug_tuple("Remove").field(remove).finish(),
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use std::collections::HashSet;
macro_rules! set {
($($val:expr),* $(,)?) => {{ #[allow(redundant_semicolons)] {
let mut set = HashSet::new();
$( set.insert($val); )* ;
set
}}}
}
#[test]
fn test_hashset_diff() {
let s: HashSet<String> = set! {
"test".into(),
"foo".into(),
};
let s1: HashSet<String> = set! {
"test".into(),
"foo".into(),
};
let diff = s.diff(&s1).unwrap();
let expected = DiffHashSet(None);
assert_eq!(diff, expected);
let s2 = s.merge(diff).unwrap();
assert_eq!(s, s2);
assert_eq!(s1, s2);
}
#[test]
fn test_hashset_diff_add_and_remove() {
let s: HashSet<String> = set! {
"test".into(),
"foo".into(),
"faux".into(),
};
let s1: HashSet<String> = set! {
"test".into(),
"foo".into(),
"bar".into(),
};
let diff = s.diff(&s1).unwrap();
let json = serde_json::to_string(&diff).unwrap();
println!("{}", json);
let diff: DiffHashSet<String> = serde_json::from_str(&json).unwrap();
println!("{:?}", diff);
}
}
