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use data_encoding::{HEXLOWER_PERMISSIVE, DecodeError};
#[cfg(feature = "serde")]
use serde::{Serialize, Serializer};
use std::error::Error;
use std::fmt;
use std::str::FromStr;
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
enum Inner {
Short([u8; 8]),
Long([u8; 16]),
}
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub struct TraceId(Inner);
impl fmt::Display for TraceId {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
for b in self.bytes() {
write!(fmt, "{:02x}", b)?;
}
Ok(())
}
}
impl FromStr for TraceId {
type Err = TraceIdParseError;
fn from_str(s: &str) -> Result<TraceId, TraceIdParseError> {
let inner = match HEXLOWER_PERMISSIVE.decode_len(s.len()) {
Ok(8) => {
let mut buf = [0; 8];
HEXLOWER_PERMISSIVE
.decode_mut(s.as_bytes(), &mut buf)
.map_err(|e| TraceIdParseError(Some(e.error)))?;
Inner::Short(buf)
}
Ok(16) => {
let mut buf = [0; 16];
HEXLOWER_PERMISSIVE
.decode_mut(s.as_bytes(), &mut buf)
.map_err(|e| TraceIdParseError(Some(e.error)))?;
Inner::Long(buf)
}
_ => return Err(TraceIdParseError(None)),
};
Ok(TraceId(inner))
}
}
#[cfg(feature = "serde")]
impl Serialize for TraceId {
fn serialize<S>(&self, s: S) -> Result<S::Ok, S::Error>
where
S: Serializer,
{
s.collect_str(self)
}
}
impl TraceId {
pub fn bytes(&self) -> &[u8] {
match self.0 {
Inner::Short(ref buf) => buf,
Inner::Long(ref buf) => buf,
}
}
}
impl From<[u8; 8]> for TraceId {
fn from(bytes: [u8; 8]) -> TraceId {
TraceId(Inner::Short(bytes))
}
}
impl From<[u8; 16]> for TraceId {
fn from(bytes: [u8; 16]) -> TraceId {
TraceId(Inner::Long(bytes))
}
}
#[derive(Debug)]
pub struct TraceIdParseError(Option<DecodeError>);
impl fmt::Display for TraceIdParseError {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
write!(fmt, "{}: ", self.description())?;
match self.0 {
Some(ref err) => write!(fmt, "{}", err),
None => fmt.write_str("invalid length"),
}
}
}
impl Error for TraceIdParseError {
fn description(&self) -> &str {
"error parsing trace ID"
}
fn cause(&self) -> Option<&Error> {
match self.0 {
Some(ref e) => Some(e),
None => None,
}
}
}