custom data type for hashes and identifiers

src/data.rs

@@ -1,8 +1,73 @@
+use std::fmt;
 use std::collections::HashMap;
-use serde::{Serialize, Deserialize};
+use serde::{Serializer, Deserializer, Serialize, Deserialize};
+use serde::de::{self, Visitor};
 
-pub type UUID = [u8; 32];
-pub type Hash = [u8; 32];
+#[derive(Default, PartialOrd, Ord, Clone, Hash, PartialEq)]
+pub struct FixedBytes32([u8; 32]);
+
+impl From<[u8; 32]> for FixedBytes32 {
+	fn from(x: [u8; 32]) -> FixedBytes32 {
+		FixedBytes32(x)
+	}
+}
+
+impl std::convert::AsRef<[u8]> for FixedBytes32 {
+	fn as_ref(&self) -> &[u8] {
+		&self.0[..]
+	}
+}
+
+impl Eq for FixedBytes32 {}
+
+impl fmt::Debug for FixedBytes32 {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		write!(f, "{}", hex::encode(self.0))
+	}
+}
+
+struct FixedBytes32Visitor;
+impl<'de> Visitor<'de> for FixedBytes32Visitor {
+	type Value = FixedBytes32;
+
+	fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+		formatter.write_str("a byte slice of size 32")
+	}
+
+	fn visit_bytes<E: de::Error>(self, value: &[u8]) -> Result<Self::Value, E> {
+		if value.len() == 32 {
+			let mut res = [0u8; 32];
+			res.copy_from_slice(value);
+			Ok(res.into())
+		} else {
+			Err(E::custom(format!("Invalid byte string length {}, expected 32", value.len())))
+		}
+	}
+}
+
+impl<'de> Deserialize<'de> for FixedBytes32 {
+	fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<FixedBytes32, D::Error> {
+		deserializer.deserialize_bytes(FixedBytes32Visitor)
+	}
+}
+
+impl Serialize for FixedBytes32 {
+	fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+		serializer.serialize_bytes(&self.0[..])
+	}
+}
+
+impl FixedBytes32 {
+	pub fn as_slice(&self) -> &[u8] {
+		&self.0[..]
+	}
+	pub fn as_slice_mut(&mut self) -> &mut [u8] {
+		&mut self.0[..]
+	}
+}
+
+pub type UUID = FixedBytes32;
+pub type Hash = FixedBytes32;
 
 
 // Network management