Add support to Serialize VariableList<FixedVector<u8, M>, N> (#10)

src/serde_utils/list_of_hex_fixed_vec.rs

@@ -0,0 +1,77 @@
+//! Serialize `VariableList<FixedVector<u8, M>, N>` as list of 0x-prefixed hex string.
+use crate::{FixedVector, VariableList};
+use serde::{ser::SerializeSeq, Deserialize, Deserializer, Serialize, Serializer};
+use std::marker::PhantomData;
+use typenum::Unsigned;
+
+#[derive(Deserialize)]
+#[serde(transparent)]
+pub struct WrappedListOwned<N: Unsigned>(
+    #[serde(with = "crate::serde_utils::hex_fixed_vec")] FixedVector<u8, N>,
+);
+
+#[derive(Serialize)]
+#[serde(transparent)]
+pub struct WrappedListRef<'a, N: Unsigned>(
+    #[serde(with = "crate::serde_utils::hex_fixed_vec")] &'a FixedVector<u8, N>,
+);
+
+pub fn serialize<S, M, N>(
+    list: &VariableList<FixedVector<u8, M>, N>,
+    serializer: S,
+) -> Result<S::Ok, S::Error>
+where
+    S: Serializer,
+    M: Unsigned,
+    N: Unsigned,
+{
+    let mut seq = serializer.serialize_seq(Some(list.len()))?;
+    for bytes in list {
+        seq.serialize_element(&WrappedListRef(bytes))?;
+    }
+    seq.end()
+}
+
+#[derive(Default)]
+pub struct Visitor<M, N> {
+    _phantom_m: PhantomData<M>,
+    _phantom_n: PhantomData<N>,
+}
+
+impl<'a, M, N> serde::de::Visitor<'a> for Visitor<M, N>
+where
+    M: Unsigned,
+    N: Unsigned,
+{
+    type Value = VariableList<FixedVector<u8, M>, N>;
+
+    fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(formatter, "a list of 0x-prefixed hex bytes")
+    }
+
+    fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
+    where
+        A: serde::de::SeqAccess<'a>,
+    {
+        let mut list: VariableList<FixedVector<u8, M>, N> = <_>::default();
+
+        while let Some(val) = seq.next_element::<WrappedListOwned<M>>()? {
+            list.push(val.0).map_err(|e| {
+                serde::de::Error::custom(format!("failed to push value to list: {:?}.", e))
+            })?;
+        }
+
+        Ok(list)
+    }
+}
+
+pub fn deserialize<'de, D, M, N>(
+    deserializer: D,
+) -> Result<VariableList<FixedVector<u8, M>, N>, D::Error>
+where
+    D: Deserializer<'de>,
+    M: Unsigned,
+    N: Unsigned,
+{
+    deserializer.deserialize_seq(Visitor::default())
+}

src/serde_utils/mod.rs

@@ -1,5 +1,6 @@
 pub mod hex_fixed_vec;
 pub mod hex_var_list;
+pub mod list_of_hex_fixed_vec;
 pub mod list_of_hex_var_list;
 pub mod quoted_u64_fixed_vec;
 pub mod quoted_u64_var_list;