use serde::{Deserialize, Serialize};
use std::fmt;
use std::ops::Deref;
use std::sync::Arc;
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct ArcStr(Arc<str>);
impl fmt::Display for ArcStr {
#[inline]
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str(self.as_ref())
}
}
impl Deref for ArcStr {
type Target = str;
#[inline]
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl From<String> for ArcStr {
#[inline]
fn from(s: String) -> Self {
Self(Arc::from(s))
}
}
impl From<&str> for ArcStr {
#[inline]
fn from(s: &str) -> Self {
Self(Arc::from(s))
}
}
impl From<Arc<str>> for ArcStr {
#[inline]
fn from(s: Arc<str>) -> Self {
Self(s)
}
}
impl Serialize for ArcStr {
#[inline]
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: serde::Serializer,
{
serializer.serialize_str(self)
}
}
impl<'de> Deserialize<'de> for ArcStr {
#[inline]
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: serde::Deserializer<'de>,
{
let s: &str = Deserialize::deserialize(deserializer)?;
Ok(ArcStr::from(s))
}
}
#[cfg(test)]
mod tests {
use super::*;
use serde_json;
#[derive(Debug, Serialize, Deserialize, PartialEq, Eq)]
struct Wrapper {
id: ArcStr,
}
#[test]
fn serialize_arcstr() {
let w = Wrapper {
id: ArcStr::from("hello"),
};
let json = serde_json::to_string(&w).unwrap();
assert_eq!(json, r#"{"id":"hello"}"#);
}
#[test]
fn deserialize_arcstr() {
let json = r#"{"id":"world"}"#;
let w: Wrapper = serde_json::from_str(json).unwrap();
assert_eq!(w.id.deref(), "world");
}
#[test]
fn display_arcstr() {
let s = ArcStr::from("test");
assert_eq!(format!("{s}"), "test");
}
#[test]
fn debug_arcstr() {
let s = ArcStr::from("test");
assert_eq!(format!("{s:?}"), r#"ArcStr("test")"#);
}
#[test]
fn arc_clone_is_shared() {
let s1 = ArcStr::from("shared");
let s2 = s1.clone();
assert!(Arc::ptr_eq(&s1.0, &s2.0));
}
#[test]
fn equality_and_hash() {
use std::collections::HashSet;
let a = ArcStr::from("id-123");
let b = ArcStr::from("id-123");
let mut set = HashSet::new();
set.insert(a.clone());
assert_eq!(a, b);
assert!(set.contains(&b));
}
}