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