Restore the coins pallet to the runtime

substrate/primitives/src/address.rs

@@ -110,6 +110,10 @@ impl core::str::FromStr for SeraiAddress {
 
 /// An address for an external network.
 #[derive(Clone, PartialEq, Eq, Debug, borsh::BorshSerialize, borsh::BorshDeserialize)]
+#[cfg_attr(
+  feature = "non_canonical_scale_derivations",
+  derive(scale::Encode, scale::Decode, scale::MaxEncodedLen)
+)]
 pub struct ExternalAddress(
   #[borsh(
     serialize_with = "crate::borsh_serialize_bounded_vec",
@@ -124,6 +128,7 @@ impl ExternalAddress {
 }
 
 /// An error when converting from a `Vec`.
+#[derive(Debug)]
 pub enum FromVecError {
   /// The source `Vec` was too long to be converted.
   TooLong,

substrate/primitives/src/balance.rs

@@ -10,11 +10,15 @@ use crate::coin::{ExternalCoin, Coin};
 pub type AmountRepr = u64;
 
 /// A wrapper used to represent amounts.
-#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, Zeroize, BorshSerialize, BorshDeserialize)]
+#[rustfmt::skip] // Prevent rustfmt from expanding the following derive into a 10-line monstrosity
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Default, Debug)]
+#[derive(Zeroize, BorshSerialize, BorshDeserialize)]
 #[cfg_attr(
   feature = "non_canonical_scale_derivations",
   derive(scale::Encode, scale::Decode, scale::MaxEncodedLen)
 )]
+#[cfg_attr(feature = "serde", derive(sp_core::serde::Serialize, sp_core::serde::Deserialize))]
+#[cfg_attr(feature = "serde", serde(crate = "sp_core::serde"))]
 pub struct Amount(pub AmountRepr);
 
 impl Add for Amount {
@@ -44,6 +48,8 @@ impl Mul for Amount {
   feature = "non_canonical_scale_derivations",
   derive(scale::Encode, scale::Decode, scale::MaxEncodedLen)
 )]
+#[cfg_attr(feature = "serde", derive(sp_core::serde::Serialize, sp_core::serde::Deserialize))]
+#[cfg_attr(feature = "serde", serde(crate = "sp_core::serde"))]
 pub struct ExternalBalance {
   /// The coin this is a balance for.
   pub coin: ExternalCoin,
@@ -78,6 +84,8 @@ impl Mul<Amount> for ExternalBalance {
   feature = "non_canonical_scale_derivations",
   derive(scale::Encode, scale::Decode, scale::MaxEncodedLen)
 )]
+#[cfg_attr(feature = "serde", derive(sp_core::serde::Serialize, sp_core::serde::Deserialize))]
+#[cfg_attr(feature = "serde", serde(crate = "sp_core::serde"))]
 pub struct Balance {
   /// The coin this is a balance for.
   pub coin: Coin,

substrate/primitives/src/coin.rs

@@ -13,6 +13,8 @@ use crate::network_id::{ExternalNetworkId, NetworkId};
   feature = "non_canonical_scale_derivations",
   derive(scale::Encode, scale::Decode, scale::MaxEncodedLen)
 )]
+#[cfg_attr(feature = "serde", derive(sp_core::serde::Serialize, sp_core::serde::Deserialize))]
+#[cfg_attr(feature = "serde", serde(crate = "sp_core::serde"))]
 #[non_exhaustive]
 pub enum ExternalCoin {
   /// Bitcoin, from the Bitcoin network.
@@ -39,6 +41,8 @@ impl ExternalCoin {
   feature = "non_canonical_scale_derivations",
   derive(scale::Encode, scale::Decode, scale::MaxEncodedLen)
 )]
+#[cfg_attr(feature = "serde", derive(sp_core::serde::Serialize, sp_core::serde::Deserialize))]
+#[cfg_attr(feature = "serde", serde(crate = "sp_core::serde"))]
 pub enum Coin {
   /// The Serai coin.
   Serai,
@@ -123,4 +127,17 @@ impl Coin {
       Coin::External(c) => c.network().into(),
     }
   }
+
+  /// The decimals used for a single human unit of this coin.
+  ///
+  /// This may be less than the decimals used for a single human unit of this coin *by defined
+  /// convention*. If so, that means Serai is *truncating* the decimals. A coin which is defined
+  /// as having 8 decimals, while Serai claims it has 4 decimals, will have `0.00019999`
+  /// interpreted as `0.0001` (in human units, in atomic units, 19999 will be interpreted as 1).
+  pub fn decimals(&self) -> u32 {
+    match self {
+      Coin::Serai => 9,
+      Coin::External(c) => c.decimals(),
+    }
+  }
 }

substrate/primitives/src/instructions/out.rs

@@ -6,6 +6,10 @@ use crate::{address::ExternalAddress, balance::ExternalBalance};
 
 /// An instruction on how to transfer coins out.
 #[derive(Clone, PartialEq, Eq, Debug, Zeroize, BorshSerialize, BorshDeserialize)]
+#[cfg_attr(
+  feature = "non_canonical_scale_derivations",
+  derive(scale::Encode, scale::Decode, scale::MaxEncodedLen)
+)]
 pub enum OutInstruction {
   /// Transfer to the specified address.
   Transfer(ExternalAddress),
@@ -13,6 +17,10 @@ pub enum OutInstruction {
 
 /// An instruction on how to transfer coins out with the balance to use for the transfer out.
 #[derive(Clone, PartialEq, Eq, Debug, Zeroize, BorshSerialize, BorshDeserialize)]
+#[cfg_attr(
+  feature = "non_canonical_scale_derivations",
+  derive(scale::Encode, scale::Decode, scale::MaxEncodedLen)
+)]
 pub struct OutInstructionWithBalance {
   /// The instruction on how to transfer coins out.
   pub instruction: OutInstruction,