scale encoding for transfer (#745)

.changelog/unreleased/improvement/745-scale-encoding-for-transfer-packet.md

@@ -0,0 +1,2 @@
+- Scale encoding for ICS-20 transfer message
+  ([#745](https://github.com/cosmos/ibc-rs/issues/745))

crates/ibc/src/applications/transfer/amount.rs

@@ -1,6 +1,6 @@
 //! Contains the `Amount` type, which represents amounts of tokens transferred.
 
-use core::str::FromStr;
+use core::{ops::Deref, str::FromStr};
 use derive_more::{Display, From, Into};
 
 use super::error::TokenTransferError;
@@ -11,6 +11,28 @@ use primitive_types::U256;
 #[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, Display, From, Into)]
 pub struct Amount(U256);
 
+#[cfg(feature = "parity-scale-codec")]
+impl parity_scale_codec::WrapperTypeDecode for Amount {
+    type Wrapped = [u64; 4];
+}
+
+#[cfg(feature = "parity-scale-codec")]
+impl parity_scale_codec::WrapperTypeEncode for Amount {}
+
+impl Deref for Amount {
+    type Target = [u64; 4];
+
+    fn deref(&self) -> &Self::Target {
+        &self.0 .0
+    }
+}
+
+impl From<[u64; 4]> for Amount {
+    fn from(value: [u64; 4]) -> Self {
+        Self(U256(value))
+    }
+}
+
 impl Amount {
     pub fn checked_add(self, rhs: Self) -> Option<Self> {
         self.0.checked_add(rhs.0).map(Self)

crates/ibc/src/applications/transfer/coin.rs

@@ -23,6 +23,10 @@ pub type RawCoin = Coin<String>;
 
 /// Coin defines a token with a denomination and an amount.
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(
+    feature = "parity-scale-codec",
+    derive(parity_scale_codec::Encode, parity_scale_codec::Decode,)
+)]
 #[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
 pub struct Coin<D> {
     /// Denomination

crates/ibc/src/applications/transfer/msgs/transfer.rs

@@ -24,6 +24,11 @@ pub(crate) const TYPE_URL: &str = "/ibc.applications.transfer.v1.MsgTransfer";
 /// have to specify the information related to the transfer of the token, and
 /// let the library figure out how to build the packet properly.
 #[derive(Clone, Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(
+    feature = "parity-scale-codec",
+    derive(parity_scale_codec::Encode, parity_scale_codec::Decode,)
+)]
 pub struct MsgTransfer {
     /// the port on which the packet will be sent
     pub port_id_on_a: PortId,

crates/ibc/src/applications/transfer/packet.rs

@@ -16,6 +16,10 @@ use crate::signer::Signer;
     feature = "serde",
     serde(try_from = "RawPacketData", into = "RawPacketData")
 )]
+#[cfg_attr(
+    feature = "parity-scale-codec",
+    derive(parity_scale_codec::Encode, parity_scale_codec::Decode,)
+)]
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct PacketData {
     pub token: PrefixedCoin,