Introduce message broker for receiving and sending relay chain messages (#80)

* Start message broker implementation * Finish first stub implementation * Add features * Fix attribute * Update primitives/src/lib.rs Co-Authored-By: Joshy Orndorff <JoshOrndorff@users.noreply.github.com> Co-authored-by: Joshy Orndorff <JoshOrndorff@users.noreply.github.com>
2026-05-30 14:01:02 +00:00 · 2020-04-20 16:22:05 +02:00
parent 028270529c
commit 41e5f0dcfd
11 changed files with 200 additions and 5 deletions
@@ -0,0 +1,75 @@
+// Copyright 2020 Parity Technologies (UK) Ltd.
+// This file is part of Cumulus.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Cumulus.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Cumulus message broker pallet.
+//!
+//! This pallet provides support for handling downward and upward messages.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+use cumulus_primitives::{
+	inherents::{DownwardMessagesType, DOWNWARD_MESSAGES_IDENTIFIER},
+	well_known_keys, DownwardMessageHandler, UpwardMessageSender,
+};
+use frame_support::{
+	decl_module, storage,
+	weights::{SimpleDispatchInfo, WeighData, Weight},
+};
+use frame_system::ensure_none;
+use sp_inherents::{InherentData, InherentIdentifier, MakeFatalError, ProvideInherent};
+
+/// Configuration trait of this pallet.
+pub trait Trait: frame_system::Trait {
+	/// The downward message handlers that will be informed when a message is received.
+	type DownwardMessageHandlers: DownwardMessageHandler;
+}
+
+decl_module! {
+	pub struct Module<T: Trait> for enum Call where origin: T::Origin {
+		/// Executes the given downward messages by calling the message handlers.
+		///
+		/// The origin of this call needs to be `None` as this is an inherent.
+		#[weight = SimpleDispatchInfo::FixedMandatory(10)]
+		fn execute_downward_messages(origin, messages: Vec<()>) {
+			ensure_none(origin)?;
+			messages.iter().for_each(T::DownwardMessageHandlers::handle_downward_message);
+		}
+
+		fn on_initialize() -> Weight {
+			storage::unhashed::kill(well_known_keys::UPWARD_MESSAGES);
+
+			SimpleDispatchInfo::default().weigh_data(())
+		}
+	}
+}
+
+impl<T: Trait> UpwardMessageSender for Module<T> {
+	fn send_upward_message(_: &()) -> Result<(), ()> {
+		Ok(())
+	}
+}
+
+impl<T: Trait> ProvideInherent for Module<T> {
+	type Call = Call<T>;
+	type Error = MakeFatalError<()>;
+	const INHERENT_IDENTIFIER: InherentIdentifier = DOWNWARD_MESSAGES_IDENTIFIER;
+
+	fn create_inherent(data: &InherentData) -> Option<Self::Call> {
+		data.get_data::<DownwardMessagesType>(&DOWNWARD_MESSAGES_IDENTIFIER)
+			.expect("Downward messages inherent data failed to decode")
+			.map(|msgs| Call::execute_downward_messages(msgs))
+	}
+}