Add Rococo<>Westend bridge support/relay (#2647)

* Added Rococo<>Westend primitives

* Latest fashion

* WIP

* Temporary hack for AssetHubWestend to Millau

* typo

* tool/runtime-codegen tweaks

* Rococo<>Westend relay part

* zepter

* Unify `Parachain` vs `Parachains`

bridges/primitives/chain-asset-hub-westend/Cargo.toml

@@ -0,0 +1,26 @@
+[package]
+name = "bp-asset-hub-westend"
+description = "Primitives of AssetHubWestend parachain runtime."
+version = "0.1.0"
+authors.workspace = true
+edition.workspace = true
+license = "GPL-3.0-or-later WITH Classpath-exception-2.0"
+
+[dependencies]
+codec = { package = "parity-scale-codec", version = "3.1.5", default-features = false }
+scale-info = { version = "2.10.0", default-features = false, features = ["derive"] }
+
+# Substrate Dependencies
+frame-support = { git = "https://github.com/paritytech/polkadot-sdk", branch = "master", default-features = false }
+
+# Bridge Dependencies
+bp-xcm-bridge-hub-router = { path = "../xcm-bridge-hub-router", default-features = false }
+
+[features]
+default = [ "std" ]
+std = [
+	"bp-xcm-bridge-hub-router/std",
+	"codec/std",
+	"frame-support/std",
+	"scale-info/std",
+]

bridges/primitives/chain-asset-hub-westend/src/lib.rs

@@ -0,0 +1,52 @@
+// Copyright (C) Parity Technologies (UK) Ltd.
+// This file is part of Parity Bridges Common.
+
+// Parity Bridges Common 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.
+
+// Parity Bridges Common 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 Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Module with configuration which reflects AssetHubWestend runtime setup.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+use codec::{Decode, Encode};
+use scale_info::TypeInfo;
+
+pub use bp_xcm_bridge_hub_router::XcmBridgeHubRouterCall;
+
+/// `AssetHubWestend` Runtime `Call` enum.
+///
+/// The enum represents a subset of possible `Call`s we can send to `AssetHubWestend` chain.
+/// Ideally this code would be auto-generated from metadata, because we want to
+/// avoid depending directly on the ENTIRE runtime just to get the encoding of `Dispatchable`s.
+///
+/// All entries here (like pretty much in the entire file) must be kept in sync with
+/// `AssetHubWestend` `construct_runtime`, so that we maintain SCALE-compatibility.
+#[allow(clippy::large_enum_variant)]
+#[derive(Encode, Decode, Debug, PartialEq, Eq, Clone, TypeInfo)]
+pub enum Call {
+	/// `ToRococoXcmRouter` bridge pallet.
+	#[codec(index = 34)]
+	ToRococoXcmRouter(XcmBridgeHubRouterCall),
+}
+
+frame_support::parameter_types! {
+	/// Some sane weight to execute `xcm::Transact(pallet-xcm-bridge-hub-router::Call::report_bridge_status)`.
+	pub const XcmBridgeHubRouterTransactCallMaxWeight: frame_support::weights::Weight = frame_support::weights::Weight::from_parts(200_000_000, 6144);
+
+	/// Base delivery fee to `BridgeHubWestend`.
+	/// (initially was calculated by test `BridgeHubWestend::can_calculate_weight_for_paid_export_message_with_reserve_transfer` + `33%`)
+	pub const BridgeHubWestendBaseFeeInWocs: u128 = 1624803349;
+}
+
+/// Identifier of AssetHubWestend in the Westend relay chain.
+pub const ASSET_HUB_WESTEND_PARACHAIN_ID: u32 = 1000;