141 lines
4.5 KiB
Rust
141 lines
4.5 KiB
Rust
// SPDX-License-Identifier: CC0-1.0
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//! Macros for serde trait implementations, and supporting code.
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//!
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/// Functions used by serde impls of all hashes.
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#[cfg(feature = "serde")]
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pub mod serde_details {
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use core::marker::PhantomData;
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use core::str::FromStr;
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use core::{fmt, ops, str};
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use crate::FromSliceError;
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struct HexVisitor<ValueT>(PhantomData<ValueT>);
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use serde::{de, Deserializer, Serializer};
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impl<'de, ValueT> de::Visitor<'de> for HexVisitor<ValueT>
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where
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ValueT: FromStr,
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<ValueT as FromStr>::Err: fmt::Display,
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{
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type Value = ValueT;
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fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
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formatter.write_str("an ASCII hex string")
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}
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fn visit_bytes<E>(self, v: &[u8]) -> Result<Self::Value, E>
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where
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E: de::Error,
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{
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if let Ok(hex) = str::from_utf8(v) {
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Self::Value::from_str(hex).map_err(E::custom)
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} else {
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return Err(E::invalid_value(de::Unexpected::Bytes(v), &self));
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}
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}
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fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
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where
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E: de::Error,
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{
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Self::Value::from_str(v).map_err(E::custom)
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}
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}
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struct BytesVisitor<ValueT>(PhantomData<ValueT>);
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impl<'de, ValueT> de::Visitor<'de> for BytesVisitor<ValueT>
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where
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ValueT: SerdeHash,
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<ValueT as FromStr>::Err: fmt::Display,
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{
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type Value = ValueT;
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fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
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formatter.write_str("a bytestring")
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}
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fn visit_bytes<E>(self, v: &[u8]) -> Result<Self::Value, E>
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where
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E: de::Error,
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{
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SerdeHash::from_slice_delegated(v).map_err(|_| {
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// from_slice only errors on incorrect length
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E::invalid_length(v.len(), &stringify!(N))
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})
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}
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}
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/// Default serialization/deserialization methods.
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pub trait SerdeHash
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where
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Self: Sized
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+ FromStr
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+ fmt::Display
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+ ops::Index<usize, Output = u8>
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+ ops::Index<ops::RangeFull, Output = [u8]>,
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<Self as FromStr>::Err: fmt::Display,
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{
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/// Size, in bits, of the hash.
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const N: usize;
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/// Helper function to turn a deserialized slice into the correct hash type.
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fn from_slice_delegated(sl: &[u8]) -> Result<Self, FromSliceError>;
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/// Do serde serialization.
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fn serialize<S: Serializer>(&self, s: S) -> Result<S::Ok, S::Error> {
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if s.is_human_readable() {
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s.collect_str(self)
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} else {
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s.serialize_bytes(&self[..])
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}
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}
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/// Do serde deserialization.
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fn deserialize<'de, D: Deserializer<'de>>(d: D) -> Result<Self, D::Error> {
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if d.is_human_readable() {
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d.deserialize_str(HexVisitor::<Self>(PhantomData))
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} else {
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d.deserialize_bytes(BytesVisitor::<Self>(PhantomData))
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}
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}
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}
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}
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/// Implements `Serialize` and `Deserialize` for a type `$t` which
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/// represents a newtype over a byte-slice over length `$len`.
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#[macro_export]
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#[cfg(feature = "serde")]
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macro_rules! serde_impl(
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($t:ident, $len:expr $(, $gen:ident: $gent:ident)*) => (
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impl<$($gen: $gent),*> $crate::serde_macros::serde_details::SerdeHash for $t<$($gen),*> {
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const N : usize = $len;
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fn from_slice_delegated(sl: &[u8]) -> Result<Self, $crate::FromSliceError> {
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#[allow(unused_imports)]
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use $crate::Hash as _;
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$t::from_slice(sl)
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}
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}
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impl<$($gen: $gent),*> $crate::serde::Serialize for $t<$($gen),*> {
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fn serialize<S: $crate::serde::Serializer>(&self, s: S) -> Result<S::Ok, S::Error> {
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$crate::serde_macros::serde_details::SerdeHash::serialize(self, s)
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}
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}
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impl<'de $(, $gen: $gent)*> $crate::serde::Deserialize<'de> for $t<$($gen),*> {
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fn deserialize<D: $crate::serde::Deserializer<'de>>(d: D) -> Result<$t<$($gen),*>, D::Error> {
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$crate::serde_macros::serde_details::SerdeHash::deserialize(d)
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}
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}
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));
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/// Does an "empty" serde implementation for the configuration without serde feature.
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#[macro_export]
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#[cfg(not(feature = "serde"))]
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macro_rules! serde_impl(
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($t:ident, $len:expr $(, $gen:ident: $gent:ident)*) => ()
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);
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