cosmrs: Coin type changes (#235)

- Implemented `serde` traits for `Denom`
- Changed internal `Coin` representation
- Getter for `Decimal`'s internal value
- Removed unused `Decimal`

cosmrs/src/base.rs

@@ -1,6 +1,6 @@
 //! Base functionality.
 
-use crate::{proto, Decimal, Error, ErrorReport, Result};
+use crate::{proto, Error, ErrorReport, Result};
 use eyre::WrapErr;
 use serde::{de, de::Error as _, ser, Deserialize, Serialize};
 use std::{fmt, str::FromStr};
@@ -128,13 +128,17 @@ impl Serialize for AccountId {
 }
 
 /// Coin defines a token with a denomination and an amount.
-#[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
+#[derive(Serialize, Deserialize, Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
 pub struct Coin {
     /// Denomination
     pub denom: Denom,
 
     /// Amount
-    pub amount: Decimal,
+    // represent coin amount as an u128, which theoretically supports lower maximum value than
+    // cosmos-sdk's `Int` that has a maximum value of 2^256 - 1. (https://github.com/cosmos/cosmos-sdk/blob/v0.45.4/types/int.go#L72-L74=)
+    // But I would argue this is sufficient for the current realistic use cases and is less cumbersome to use than the `Decimal`
+    // (which should have been used for a `DecCoin`)
+    pub amount: u128,
 }
 
 impl TryFrom<proto::cosmos::base::v1beta1::Coin> for Coin {
@@ -171,6 +175,15 @@ impl From<&Coin> for proto::cosmos::base::v1beta1::Coin {
     }
 }
 
+impl fmt::Display for Coin {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        // Follow the same formatting without the space between amount and denom as
+        // Cosmwasm in their Coin, which is furthermore consistent with the cosmos-sdk:
+        // https://github.com/cosmos/cosmos-sdk/blob/v0.42.4/types/coin.go#L643-L645
+        write!(f, "{}{}", self.amount, self.denom)
+    }
+}
+
 /// Denomination.
 #[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
 pub struct Denom(String);
@@ -202,6 +215,20 @@ impl FromStr for Denom {
     }
 }
 
+impl<'de> Deserialize<'de> for Denom {
+    fn deserialize<D: de::Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
+        String::deserialize(deserializer)?
+            .parse()
+            .map_err(D::Error::custom)
+    }
+}
+
+impl Serialize for Denom {
+    fn serialize<S: ser::Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+        self.0.serialize(serializer)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::{AccountId, Denom};

cosmrs/src/lib.rs

@@ -34,13 +34,11 @@ pub mod cosmwasm;
 pub mod dev;
 
 mod base;
-mod decimal;
 mod error;
 mod prost_ext;
 
 pub use crate::{
     base::{AccountId, Coin, Denom},
-    decimal::Decimal,
     error::{Error, Result},
     tx::Tx,
 };

cosmrs/src/tx.rs

@@ -47,7 +47,7 @@
 //! // We'll be doing a simple send transaction.
 //! // First we'll create a "Coin" amount to be sent, in this case 1 million uatoms.
 //! let amount = Coin {
-//!     amount: 1_000_000u64.into(),
+//!     amount: 1_000_000u128,
 //!     denom: "uatom".parse()?,
 //! };
 //!

cosmrs/src/tx/fee.rs

@@ -2,13 +2,14 @@
 
 use super::Gas;
 use crate::{prost_ext::ParseOptional, proto, AccountId, Coin, ErrorReport, Result};
+use serde::{Deserialize, Serialize};
 
 /// Fee includes the amount of coins paid in fees and the maximum gas to be
 /// used by the transaction.
 ///
 /// The ratio yields an effective “gasprice”, which must be above some minimum
 /// to be accepted into the mempool.
-#[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
+#[derive(Clone, Debug, Deserialize, Eq, PartialEq, PartialOrd, Ord, Serialize)]
 pub struct Fee {
     /// Amount of coins to be paid as a fee.
     pub amount: Vec<Coin>,