Update test runtime for downward messages

test/parachain/runtime/src/lib.rs

@@ -243,6 +243,7 @@ impl message_example::Trait for Runtime {
 	type Event = Event;
 	type UpwardMessageSender = MessageBroker;
 	type UpwardMessage = cumulus_upward_message::WestendUpwardMessage;
+	type Currency = Balances;
 }
 
 construct_runtime! {
@@ -258,7 +259,7 @@ construct_runtime! {
 		RandomnessCollectiveFlip: pallet_randomness_collective_flip::{Module, Call, Storage},
 		ParachainUpgrade: cumulus_parachain_upgrade::{Module, Call, Storage, Inherent, Event},
 		MessageBroker: cumulus_message_broker::{Module, Call, Inherent, Event<T>},
-		TokenDealer: message_example::{Module, Call, Event},
+		TokenDealer: message_example::{Module, Call, Event<T>},
 		TransactionPayment: pallet_transaction_payment::{Module, Storage},
 	}
 }

test/parachain/runtime/src/message_example.rs

@@ -17,31 +17,41 @@
 //! Example Pallet that shows how to send upward messages and how to receive
 //! downward messages.
 
-use frame_support::{decl_event, decl_module};
+use frame_support::{decl_event, decl_module, traits::Currency};
 use frame_system::ensure_signed;
 
+use codec::{Decode, Encode};
 use cumulus_primitives::{
-	relay_chain::{AccountId as RAccountId, Balance as RBalance},
-	UpwardMessageOrigin, UpwardMessageSender,
+	relay_chain::DownwardMessage, DownwardMessageHandler, UpwardMessageOrigin, UpwardMessageSender,
 };
 use cumulus_upward_message::BalancesMessage;
 
+type BalanceOf<T> = <<T as Trait>::Currency as Currency<<T as frame_system::Trait>::AccountId>>::Balance;
+
 /// Configuration trait of this pallet.
 pub trait Trait: frame_system::Trait {
 	/// Event type used by the runtime.
-	type Event: From<Event> + Into<<Self as frame_system::Trait>::Event>;
+	type Event: From<Event<Self>> + Into<<Self as frame_system::Trait>::Event>;
 
 	/// The sender of upward messages.
 	type UpwardMessageSender: UpwardMessageSender<Self::UpwardMessage>;
 
 	/// The upward message type used by the Parachain runtime.
-	type UpwardMessage: codec::Codec + BalancesMessage;
+	type UpwardMessage: codec::Codec + BalancesMessage<Self::AccountId, BalanceOf<Self>>;
+
+	/// Currency of the runtime.
+	type Currency: Currency<Self::AccountId>;
 }
 
 decl_event! {
-	pub enum Event {
+	pub enum Event<T> where
+		AccountId = <T as frame_system::Trait>::AccountId,
+		Balance = BalanceOf<T>
+	{
 		/// Transferred tokens to the account on the relay chain.
-		TransferredTokens(RAccountId, RBalance),
+		TransferredTokensToRelayChain(AccountId, Balance),
+		/// Transferred tokens to the account on request from the relay chain.
+		TransferredTokensFromRelayChain(AccountId, Balance),
 	}
 }
 
@@ -50,17 +60,37 @@ decl_module! {
 		/// Transfer `amount` of tokens on the relay chain from the Parachain account to
 		/// the given `dest` account.
 		#[weight = 10]
-		fn transfer_tokens(origin, dest: RAccountId, amount: RBalance) {
+		fn transfer_tokens(origin, dest: T::AccountId, amount: BalanceOf<T>) {
 			//TODO: Remove the tokens from the given account
 			ensure_signed(origin)?;
 
-			let msg = <T as Trait>::UpwardMessage::transfer(dest.clone(), amount);
+			let msg = <T as Trait>::UpwardMessage::transfer(dest.clone(), amount.clone());
 			<T as Trait>::UpwardMessageSender::send_upward_message(&msg, UpwardMessageOrigin::Signed)
 				.expect("Should not fail; qed");
 
-			Self::deposit_event(Event::TransferredTokens(dest, amount));
+			Self::deposit_event(Event::<T>::TransferredTokensToRelayChain(dest, amount));
 		}
 
 		fn deposit_event() = default;
 	}
 }
+
+fn convert_hack<O: Decode>(input: &impl Encode) -> O {
+	input.using_encoded(|e| Decode::decode(&mut &e[..]).expect("Must be compatible; qed"))
+}
+
+impl<T: Trait> DownwardMessageHandler for Module<T> {
+	fn handle_downward_message(msg: &DownwardMessage) {
+		match msg {
+			DownwardMessage::TransferInto(dest, amount, _) => {
+				let dest = convert_hack(&dest);
+				let amount: BalanceOf<T> = convert_hack(amount);
+
+				let _ = T::Currency::deposit_creating(&dest, amount.clone());
+
+				Self::deposit_event(Event::<T>::TransferredTokensFromRelayChain(dest, amount));
+			}
+			_ => {}
+		}
+	}
+}

upward-message/src/kusama.rs

@@ -23,7 +23,7 @@ use kusama_runtime::BalancesCall;
 /// The Kusama upward message.
 pub type UpwardMessage = kusama_runtime::Call;
 
-impl BalancesMessage for UpwardMessage {
+impl BalancesMessage<AccountId, Balance> for UpwardMessage {
 	fn transfer(dest: AccountId, amount: Balance) -> Self {
 		BalancesCall::transfer(dest, amount).into()
 	}

upward-message/src/lib.rs

@@ -22,8 +22,6 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
-use polkadot_core_primitives::{Balance, AccountId};
-
 mod polkadot;
 mod kusama;
 mod westend;
@@ -33,7 +31,7 @@ pub use kusama::UpwardMessage as KusamaUpwardMessage;
 pub use westend::UpwardMessage as WestendUpwardMessage;
 
 /// A `Balances` related upward message.
-pub trait BalancesMessage: Sized {
+pub trait BalancesMessage<AccountId, Balance>: Sized {
 	/// Transfer the given `amount` from the parachain account to the given
 	/// `dest` account.
 	fn transfer(dest: AccountId, amount: Balance) -> Self;

upward-message/src/polkadot.rs

@@ -23,7 +23,7 @@ use polkadot_runtime::BalancesCall;
 /// The Polkadot upward message.
 pub type UpwardMessage = polkadot_runtime::Call;
 
-impl BalancesMessage for UpwardMessage {
+impl BalancesMessage<AccountId, Balance> for UpwardMessage {
 	fn transfer(dest: AccountId, amount: Balance) -> Self {
 		BalancesCall::transfer(dest, amount).into()
 	}

upward-message/src/westend.rs

@@ -23,7 +23,7 @@ use westend_runtime::BalancesCall;
 /// The Westend upward message.
 pub type UpwardMessage = westend_runtime::Call;
 
-impl BalancesMessage for UpwardMessage {
+impl BalancesMessage<AccountId, Balance> for UpwardMessage {
 	fn transfer(dest: AccountId, amount: Balance) -> Self {
 		BalancesCall::transfer(dest, amount).into()
 	}