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#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
pub struct Id(u128);
impl Id {
pub fn generate() -> Id {
Id(rand::random())
}
}
#[derive(Debug)]
pub struct ParseIdError;
impl std::fmt::Display for ParseIdError {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "parse id error")
}
}
impl std::error::Error for ParseIdError {}
impl std::str::FromStr for Id {
type Err = ParseIdError;
fn from_str(s: &str) -> Result<Self, Self::Err> {
if s.len() != 32 {
return Err(ParseIdError);
}
let id = u128::from_str_radix(s, 16).map_err(|_| ParseIdError)?;
let id = Id(id);
Ok(id)
}
}
impl std::fmt::Display for Id {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "{:032x?}", self.0)
}
}
impl serde::Serialize for Id {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: serde::Serializer,
{
serializer.serialize_str(&self.to_string())
}
}
struct IdVisitor;
impl<'de> serde::de::Visitor<'de> for IdVisitor {
type Value = Id;
fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
formatter.write_str("a string")
}
fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
where
E: serde::de::Error,
{
value.parse().map_err(|_| E::custom("invalid id"))
}
}
impl<'de> serde::Deserialize<'de> for Id {
fn deserialize<D>(deserializer: D) -> Result<Id, D::Error>
where
D: serde::Deserializer<'de>,
{
deserializer.deserialize_str(IdVisitor)
}
}
#[test]
fn test_parse() {
let s = "00000000000000000000000000000000";
assert_eq!(s.parse::<Id>().unwrap().to_string(), s);
let s = "0000000000000000000000000000000z";
assert!(s.parse::<Id>().is_err());
let s = "f51a3a61ee9d4731b1b06c816a8ab856";
assert_eq!(s.parse::<Id>().unwrap().to_string(), s);
let s = "abc123";
assert!(s.parse::<Id>().is_err());
}