rust-secp256k1-unsafe-fast/src/serde_util.rs

115 lines
2.9 KiB
Rust

use core::fmt;
use core::marker::PhantomData;
use core::str::{self, FromStr};
use serde::de;
/// A serde visitor that works for `T`s implementing `FromStr`.
pub struct FromStrVisitor<T> {
expectation: &'static str,
_pd: PhantomData<T>,
}
impl<T> FromStrVisitor<T> {
pub fn new(expectation: &'static str) -> Self {
FromStrVisitor { expectation, _pd: PhantomData }
}
}
impl<'de, T> de::Visitor<'de> for FromStrVisitor<T>
where
T: FromStr,
<T as FromStr>::Err: fmt::Display,
{
type Value = T;
fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
formatter.write_str(self.expectation)
}
fn visit_str<E: de::Error>(self, v: &str) -> Result<Self::Value, E> {
FromStr::from_str(v).map_err(E::custom)
}
}
pub struct BytesVisitor<F> {
expectation: &'static str,
parse_fn: F,
}
impl<F, T, Err> BytesVisitor<F>
where
F: FnOnce(&[u8]) -> Result<T, Err>,
Err: fmt::Display,
{
pub fn new(expectation: &'static str, parse_fn: F) -> Self {
BytesVisitor { expectation, parse_fn }
}
}
impl<'de, F, T, Err> de::Visitor<'de> for BytesVisitor<F>
where
F: FnOnce(&[u8]) -> Result<T, Err>,
Err: fmt::Display,
{
type Value = T;
fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
formatter.write_str(self.expectation)
}
fn visit_bytes<E: de::Error>(self, v: &[u8]) -> Result<Self::Value, E> {
(self.parse_fn)(v).map_err(E::custom)
}
}
macro_rules! impl_tuple_visitor {
($thing:ident, $len:expr) => {
pub(crate) struct $thing<F> {
expectation: &'static str,
parse_fn: F,
}
impl<F, T, E> $thing<F>
where
F: FnOnce(&[u8]) -> Result<T, E>,
E: fmt::Display,
{
pub fn new(expectation: &'static str, parse_fn: F) -> Self {
$thing { expectation, parse_fn }
}
}
impl<'de, F, T, E> de::Visitor<'de> for $thing<F>
where
F: FnOnce(&[u8]) -> Result<T, E>,
E: fmt::Display,
{
type Value = T;
fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
formatter.write_str(self.expectation)
}
fn visit_seq<V>(self, mut seq: V) -> Result<Self::Value, V::Error>
where
V: de::SeqAccess<'de>,
{
let mut bytes = [0u8; $len];
for (i, byte) in bytes.iter_mut().enumerate() {
if let Some(value) = seq.next_element()? {
*byte = value;
} else {
return Err(de::Error::invalid_length(i, &self));
}
}
(self.parse_fn)(&bytes).map_err(de::Error::custom)
}
}
};
}
impl_tuple_visitor!(Tuple32Visitor, 32);
impl_tuple_visitor!(Tuple33Visitor, 33);