Implement basic upward & downward messages (#118)

* Start by replacing branch names and set `DownwardMessage`

* Add the upward-message crate

* Add Kusama & Polkadot

* More work on getting the upward messages working

* Fix build

* Begin to integrate it into the test Parachain

* Update

* Make everything compile again

* Switch to westend and print parachain account on startup

* Use MultiSignature etc

* Fix validate block

* Some downward messages work

* Update git reference

* More downward messages integration

* Update test runtime for downward messages

* Enable downward message handler and withdraw send tokens

* Add some docs

* Begin to implement simple XCMP

* More work

* Fixes and make parachain id configurable

* Make parachain ID be part of the genesis

* Finishing the XCMP message demo

* Update and fixes tests

* Update branch

primitives/src/lib.rs

@@ -18,7 +18,18 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
+pub use polkadot_core_primitives as relay_chain;
+pub use polkadot_core_primitives::DownwardMessage;
+/// A generic upward message from a Parachain to the Relay Chain.
+///
+/// It is "generic" in such a way, that the actual message is encoded in the `data` field.
+/// Besides the `data` it also holds the `origin` of the message.
+pub use polkadot_parachain::primitives::UpwardMessage as GenericUpwardMessage;
+pub use polkadot_parachain::primitives::ParachainDispatchOrigin as UpwardMessageOrigin;
+pub use polkadot_parachain::primitives::Id as ParaId;
+
 pub mod validation_function_params;
+pub mod xcmp;
 
 use codec::{Decode, Encode};
 use sp_runtime::traits::Block as BlockT;
@@ -31,7 +42,7 @@ pub mod inherents {
 	pub const DOWNWARD_MESSAGES_IDENTIFIER: InherentIdentifier = *b"cumdownm";
 
 	/// The type of the inherent downward messages.
-	pub type DownwardMessagesType = sp_std::vec::Vec<()>;
+	pub type DownwardMessagesType = sp_std::vec::Vec<crate::DownwardMessage>;
 
 	/// The identifier for the `validation_function_params` inherent.
 	pub const VALIDATION_FUNCTION_PARAMS_IDENTIFIER: InherentIdentifier = *b"valfunp0";
@@ -43,29 +54,34 @@ pub mod inherents {
 pub mod well_known_keys {
 	/// The storage key for the upward messages.
 	///
-	/// The upward messages are stored as SCALE encoded `Vec<()>`.
+	/// The upward messages are stored as SCALE encoded `Vec<GenericUpwardMessage>`.
 	pub const UPWARD_MESSAGES: &'static [u8] = b":cumulus_upward_messages:";
 
 	/// Current validation function parameters.
-	pub const VALIDATION_FUNCTION_PARAMS: &'static [u8] = b":validation_function_params";
+	pub const VALIDATION_FUNCTION_PARAMS: &'static [u8] = b":cumulus_validation_function_params";
 
 	/// Code upgarde (set as appropriate by a pallet).
-	pub const NEW_VALIDATION_CODE: &'static [u8] = b":new_validation_code";
+	pub const NEW_VALIDATION_CODE: &'static [u8] = b":cumulus_new_validation_code";
+
+	/// The storage key for the processed downward messages.
+	///
+	/// The value is stored as SCALE encoded `u32`.
+	pub const PROCESSED_DOWNWARD_MESSAGES: &'static [u8] = b":cumulus_processed_downward_messages:";
 }
 
 /// Something that should be called when a downward message is received.
 #[impl_trait_for_tuples::impl_for_tuples(30)]
 pub trait DownwardMessageHandler {
 	/// Handle the given downward message.
-	fn handle_downward_message(msg: &());
+	fn handle_downward_message(msg: &DownwardMessage);
 }
 
 /// Something that can send upward messages.
-pub trait UpwardMessageSender {
+pub trait UpwardMessageSender<UpwardMessage> {
 	/// Send an upward message to the relay chain.
 	///
 	/// Returns an error if sending failed.
-	fn send_upward_message(msg: &()) -> Result<(), ()>;
+	fn send_upward_message(msg: &UpwardMessage, origin: UpwardMessageOrigin) -> Result<(), ()>;
 }
 
 /// The head data of the parachain, stored in the relay chain.

primitives/src/xcmp.rs

@@ -0,0 +1,42 @@
+// 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/>.
+
+//! XMCP related primitives
+
+use polkadot_primitives::parachain::Id as ParaId;
+use sp_std::vec::Vec;
+
+/// A raw XCMP message that is being send between two Parachain's.
+#[derive(codec::Encode, codec::Decode)]
+pub struct RawXCMPMessage {
+	/// Parachain sending the message.
+	pub from: ParaId,
+	/// SCALE encoded message.
+	pub data: Vec<u8>,
+}
+
+/// Something that can handle XCMP messages.
+#[impl_trait_for_tuples::impl_for_tuples(30)]
+pub trait XCMPMessageHandler<Message: codec::Decode> {
+	/// Handle a XCMP message.
+	fn handle_xcmp_message(src: ParaId, msg: &Message);
+}
+
+/// Something that can send XCMP messages.
+pub trait XCMPMessageSender<Message: codec::Encode> {
+	/// Send a XCMP message to the given parachain.
+	fn send_xcmp_message(dest: ParaId, msg: &Message) -> Result<(), ()>;
+}