Move ChainWithBalances::NativeBalance -> Chain::Balance (#990)

* move ChainWithBalances::NativeBalance -> Chain::Balance

* dummy commit

* Revert "dummy commit"

This reverts commit c00642153d260685a91d4fffbc424d225741fceb.

bridges/relays/client-substrate/src/chain.rs

@@ -54,14 +54,16 @@ pub trait Chain: ChainBase + Clone {
 	type SignedBlock: Member + Serialize + DeserializeOwned + BlockWithJustification<Self::Header>;
 	/// The aggregated `Call` type.
 	type Call: Dispatchable + Debug;
+	/// Balance of an account in native tokens.
+	///
+	/// The chain may suport multiple tokens, but this particular type is for token that is used
+	/// to pay for transaction dispatch, to reward different relayers (headers, messages), etc.
+	type Balance: Parameter + Member + DeserializeOwned + Clone + Copy + CheckedSub + PartialOrd + Zero;
 }
 
 /// Substrate-based chain with `frame_system::Config::AccountData` set to
-/// the `pallet_balances::AccountData<NativeBalance>`.
+/// the `pallet_balances::AccountData<Balance>`.
 pub trait ChainWithBalances: Chain {
-	/// Balance of an account in native tokens.
-	type NativeBalance: Parameter + Member + DeserializeOwned + Clone + Copy + CheckedSub + PartialOrd + Zero;
-
 	/// Return runtime storage key for getting `frame_system::AccountInfo` of given account.
 	fn account_info_storage_key(account_id: &Self::AccountId) -> StorageKey;
 }

bridges/relays/client-substrate/src/client.rs

@@ -208,7 +208,7 @@ impl<C: Chain> Client<C> {
 	}
 
 	/// Return native tokens balance of the account.
-	pub async fn free_native_balance(&self, account: C::AccountId) -> Result<C::NativeBalance>
+	pub async fn free_native_balance(&self, account: C::AccountId) -> Result<C::Balance>
 	where
 		C: ChainWithBalances,
 	{
@@ -217,7 +217,7 @@ impl<C: Chain> Client<C> {
 			.await?
 			.ok_or(Error::AccountDoesNotExist)?;
 		let decoded_account_data =
-			AccountInfo::<C::Index, AccountData<C::NativeBalance>>::decode(&mut &encoded_account_data.0[..])
+			AccountInfo::<C::Index, AccountData<C::Balance>>::decode(&mut &encoded_account_data.0[..])
 				.map_err(Error::ResponseParseFailed)?;
 		Ok(decoded_account_data.data.free)
 	}

bridges/relays/client-substrate/src/guard.rs

@@ -33,7 +33,7 @@ pub trait Environment<C: ChainWithBalances>: Send + Sync + 'static {
 	/// Return current runtime version.
 	async fn runtime_version(&mut self) -> Result<RuntimeVersion, String>;
 	/// Return free native balance of the account on the chain.
-	async fn free_native_balance(&mut self, account: C::AccountId) -> Result<C::NativeBalance, String>;
+	async fn free_native_balance(&mut self, account: C::AccountId) -> Result<C::Balance, String>;
 
 	/// Return current time.
 	fn now(&self) -> Instant {
@@ -85,7 +85,7 @@ pub fn abort_on_spec_version_change<C: ChainWithBalances>(mut env: impl Environm
 pub fn abort_when_account_balance_decreased<C: ChainWithBalances>(
 	mut env: impl Environment<C>,
 	account_id: C::AccountId,
-	maximal_decrease: C::NativeBalance,
+	maximal_decrease: C::Balance,
 ) {
 	const DAY: Duration = Duration::from_secs(60 * 60 * 24);
 
@@ -155,7 +155,7 @@ impl<C: ChainWithBalances> Environment<C> for Client<C> {
 		Client::<C>::runtime_version(self).await.map_err(|e| e.to_string())
 	}
 
-	async fn free_native_balance(&mut self, account: C::AccountId) -> Result<C::NativeBalance, String> {
+	async fn free_native_balance(&mut self, account: C::AccountId) -> Result<C::Balance, String> {
 		Client::<C>::free_native_balance(self, account)
 			.await
 			.map_err(|e| e.to_string())
@@ -191,11 +191,10 @@ mod tests {
 		type SignedBlock =
 			sp_runtime::generic::SignedBlock<sp_runtime::generic::Block<Self::Header, sp_runtime::OpaqueExtrinsic>>;
 		type Call = ();
+		type Balance = u32;
 	}
 
 	impl ChainWithBalances for TestChain {
-		type NativeBalance = u32;
-
 		fn account_info_storage_key(_account_id: &u32) -> sp_core::storage::StorageKey {
 			unreachable!()
 		}