Initial version of bridging pallets as git subtree (#2458)

* Initial version of bridges pallet as subtree of https://github.com/paritytech/parity-bridges-common
Added `Bridges subtree files` pr review rule

* Squashed 'bridges/' content from commit d30927c08

git-subtree-dir: bridges
git-subtree-split: d30927c089bd9e73092d1ec1a62895603cb277a3

* Updated REAMDE.md and BRIDGES.md (inspired by original https://github.com/paritytech/polkadot/blob/d22eb62fe40e55e15eb91d375f48cc540d83a47e/BRIDGES.md)

* Squashed 'bridges/' changes from d30927c08..d3970944b

d3970944b Small simplifications (#2050)

git-subtree-dir: bridges
git-subtree-split: d3970944b0cfc4ea5226225e1ca07dab234c3556

* Squashed 'bridges/' changes from d3970944b..2180797fb

2180797fb Removed CODEOWNERS (#2051)

git-subtree-dir: bridges
git-subtree-split: 2180797fbf8a990490c67853dcffd81bc8dd083c

* Squashed 'bridges/' changes from 2180797fbf..4850aac8ce

4850aac8ce Removed relayer_account: &AccountId from MessageDispatch  (#2080)
8c8adafd54 Revert "Fix max-size messages at test chains (#2064)" (#2077)
c01a63efd8 Fixed off-by-one when confirming rewards in messages pallet (#2075)
a298be96aa Update subxt dependencies (#2072)
c0eef51eab Fix max-size messages at test chains (#2064)
3a658e3697 Messages relay fixes (#2073)
0022b5ab22 Slash relayers for invalid transactions (#2025)
198104007f Bump enumflags2 from 0.7.5 to 0.7.7
9229b257e5 [ci] Fix rules for docker build (#2069)
660d791390 [ci] Update buildah command and version (#2058)
e4535c0ca4 fix the way latest_confirmed_nonce_at_source is "calculated" (#2067)
dbc2d37590 select nothing if we have already selected nonces to submit or have submitted something (#2065)
a7eedd21fe [relay-substrate-client] Bump jsonrpsee (#2066)
8875d5aeae Bump clap from 4.2.2 to 4.2.4
25f9cf55e2 Another use of RangeInclusiveExt::checked_len() (#2060)
4942c12a5f submit lane unblock transactions from relay (#2030)
c0325d3c9c Test deployments fixes (#2057)
fc7b9b7ed7 Use the new matrix server (#2056)
63bcb5c10b Fixed delivery alert rule (#2052)

git-subtree-dir: bridges
git-subtree-split: 4850aac8ce6c34e5ca6246b88cd14c873a879cba

* Squashed 'bridges/' changes from 4850aac8ce..66aaf0dd23

66aaf0dd23 Nits (#2083)

git-subtree-dir: bridges
git-subtree-split: 66aaf0dd239dde40b64264061a77c921e2c82568

* Squashed 'bridges/' changes from 66aaf0dd23..557ecbcecc

557ecbcecc Fix sized messages (Follow-up on #2064) (#2103)
54f587a066 Add weight of refund extension post_dispatch to the weights of messages pallet (#2089)
5b1626f8c4 fix pallet param for nightly benchmarks check (#2099)
ae44c6b7a1 Add millau specific messages weights (#2097)
6ad0bd1f1e Add integrity tests to rialto parachain runtiime (#2096)
6919556de5 Bump tokio from 1.27.0 to 1.28.0
58795fcb75 Bump clap from 4.2.4 to 4.2.5
01bf31085b Bump scale-info from 2.5.0 to 2.6.0
8fe383240d Bump anyhow from 1.0.70 to 1.0.71
8d94e82ad5 deployments: add new BEEFY metrics and alarms (#2090)
e9a4749e7e Bump wasmtime from 6.0.1 to 6.0.2
9d9936c0d9 Bump wasmtime from 6.0.1 to 6.0.2 in /tools/runtime-codegen
5d77cd7bee Add more logs to relayer and message pallets (#2082)
75fbb9d3ef Update comment (#2081)
9904d09cf6 Benchmarks for new relayers pallet calls (#2040)

git-subtree-dir: bridges
git-subtree-split: 557ecbcecc585547b744a5ac9fb8d7f3b9de4521

* fmt

* Squashed 'bridges/' changes from 557ecbcecc..04b3dda6aa

04b3dda6aa Remove from subtree (#2111)
f8ff15e7e7 Add `MessagesPalletInstance` for integrity tests (#2107)
92ccef58e6 Use generated runtimes for BHR/BHW (#2106)
b33e0a585b Fix comment (#2105)

git-subtree-dir: bridges
git-subtree-split: 04b3dda6aa38599e612ff637710b6d2cff275ef3

* ".git/.scripts/commands/fmt/fmt.sh"

---------

Co-authored-by: parity-processbot <>

bridges/primitives/header-chain/src/lib.rs

@@ -0,0 +1,227 @@
+// Copyright 2019-2021 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/>.
+
+//! Defines traits which represent a common interface for Substrate pallets which want to
+//! incorporate bridge functionality.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+use bp_runtime::{
+	BasicOperatingMode, Chain, HashOf, HasherOf, HeaderOf, RawStorageProof, StorageProofChecker,
+	StorageProofError,
+};
+use codec::{Codec, Decode, Encode, EncodeLike, MaxEncodedLen};
+use core::{clone::Clone, cmp::Eq, default::Default, fmt::Debug};
+use frame_support::PalletError;
+use scale_info::TypeInfo;
+#[cfg(feature = "std")]
+use serde::{Deserialize, Serialize};
+use sp_consensus_grandpa::{AuthorityList, ConsensusLog, SetId, GRANDPA_ENGINE_ID};
+use sp_runtime::{traits::Header as HeaderT, Digest, RuntimeDebug};
+use sp_std::boxed::Box;
+
+pub mod justification;
+pub mod storage_keys;
+
+/// Header chain error.
+#[derive(Clone, Decode, Encode, Eq, PartialEq, PalletError, Debug, TypeInfo)]
+pub enum HeaderChainError {
+	/// Header with given hash is missing from the chain.
+	UnknownHeader,
+	/// Storage proof related error.
+	StorageProof(StorageProofError),
+}
+
+/// Header data that we're storing on-chain.
+///
+/// Even though we may store full header, our applications (XCM) only use couple of header
+/// fields. Extracting those values makes on-chain storage and PoV smaller, which is good.
+#[derive(Clone, Decode, Encode, Eq, MaxEncodedLen, PartialEq, RuntimeDebug, TypeInfo)]
+pub struct StoredHeaderData<Number, Hash> {
+	/// Header number.
+	pub number: Number,
+	/// Header state root.
+	pub state_root: Hash,
+}
+
+/// Stored header data builder.
+pub trait StoredHeaderDataBuilder<Number, Hash> {
+	/// Build header data from self.
+	fn build(&self) -> StoredHeaderData<Number, Hash>;
+}
+
+impl<H: HeaderT> StoredHeaderDataBuilder<H::Number, H::Hash> for H {
+	fn build(&self) -> StoredHeaderData<H::Number, H::Hash> {
+		StoredHeaderData { number: *self.number(), state_root: *self.state_root() }
+	}
+}
+
+/// Substrate header chain, abstracted from the way it is stored.
+pub trait HeaderChain<C: Chain> {
+	/// Returns state (storage) root of given finalized header.
+	fn finalized_header_state_root(header_hash: HashOf<C>) -> Option<HashOf<C>>;
+	/// Parse storage proof using finalized header.
+	fn parse_finalized_storage_proof<R>(
+		header_hash: HashOf<C>,
+		storage_proof: RawStorageProof,
+		parse: impl FnOnce(StorageProofChecker<HasherOf<C>>) -> R,
+	) -> Result<R, HeaderChainError> {
+		let state_root = Self::finalized_header_state_root(header_hash)
+			.ok_or(HeaderChainError::UnknownHeader)?;
+		let storage_proof_checker = bp_runtime::StorageProofChecker::new(state_root, storage_proof)
+			.map_err(HeaderChainError::StorageProof)?;
+
+		Ok(parse(storage_proof_checker))
+	}
+}
+
+/// A type that can be used as a parameter in a dispatchable function.
+///
+/// When using `decl_module` all arguments for call functions must implement this trait.
+pub trait Parameter: Codec + EncodeLike + Clone + Eq + Debug + TypeInfo {}
+impl<T> Parameter for T where T: Codec + EncodeLike + Clone + Eq + Debug + TypeInfo {}
+
+/// A GRANDPA Authority List and ID.
+#[derive(Default, Encode, Eq, Decode, RuntimeDebug, PartialEq, Clone, TypeInfo)]
+#[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
+pub struct AuthoritySet {
+	/// List of GRANDPA authorities for the current round.
+	pub authorities: AuthorityList,
+	/// Monotonic identifier of the current GRANDPA authority set.
+	pub set_id: SetId,
+}
+
+impl AuthoritySet {
+	/// Create a new GRANDPA Authority Set.
+	pub fn new(authorities: AuthorityList, set_id: SetId) -> Self {
+		Self { authorities, set_id }
+	}
+}
+
+/// Data required for initializing the GRANDPA bridge pallet.
+///
+/// The bridge needs to know where to start its sync from, and this provides that initial context.
+#[derive(Default, Encode, Decode, RuntimeDebug, PartialEq, Eq, Clone, TypeInfo)]
+#[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
+pub struct InitializationData<H: HeaderT> {
+	/// The header from which we should start syncing.
+	pub header: Box<H>,
+	/// The initial authorities of the pallet.
+	pub authority_list: AuthorityList,
+	/// The ID of the initial authority set.
+	pub set_id: SetId,
+	/// Pallet operating mode.
+	pub operating_mode: BasicOperatingMode,
+}
+
+/// Abstract finality proof that is justifying block finality.
+pub trait FinalityProof<Number>: Clone + Send + Sync + Debug {
+	/// Return number of header that this proof is generated for.
+	fn target_header_number(&self) -> Number;
+}
+
+/// A trait that provides helper methods for querying the consensus log.
+pub trait ConsensusLogReader {
+	/// Returns true if digest contains item that schedules authorities set change.
+	fn schedules_authorities_change(digest: &Digest) -> bool;
+}
+
+/// A struct that provides helper methods for querying the GRANDPA consensus log.
+pub struct GrandpaConsensusLogReader<Number>(sp_std::marker::PhantomData<Number>);
+
+impl<Number: Codec> GrandpaConsensusLogReader<Number> {
+	pub fn find_authorities_change(
+		digest: &Digest,
+	) -> Option<sp_consensus_grandpa::ScheduledChange<Number>> {
+		// find the first consensus digest with the right ID which converts to
+		// the right kind of consensus log.
+		digest
+			.convert_first(|log| log.consensus_try_to(&GRANDPA_ENGINE_ID))
+			.and_then(|log| match log {
+				ConsensusLog::ScheduledChange(change) => Some(change),
+				_ => None,
+			})
+	}
+}
+
+impl<Number: Codec> ConsensusLogReader for GrandpaConsensusLogReader<Number> {
+	fn schedules_authorities_change(digest: &Digest) -> bool {
+		GrandpaConsensusLogReader::<Number>::find_authorities_change(digest).is_some()
+	}
+}
+
+/// A minimized version of `pallet-bridge-grandpa::Call` that can be used without a runtime.
+#[derive(Encode, Decode, Debug, PartialEq, Eq, Clone, TypeInfo)]
+#[allow(non_camel_case_types)]
+pub enum BridgeGrandpaCall<Header: HeaderT> {
+	/// `pallet-bridge-grandpa::Call::submit_finality_proof`
+	#[codec(index = 0)]
+	submit_finality_proof {
+		finality_target: Box<Header>,
+		justification: justification::GrandpaJustification<Header>,
+	},
+	/// `pallet-bridge-grandpa::Call::initialize`
+	#[codec(index = 1)]
+	initialize { init_data: InitializationData<Header> },
+}
+
+/// The `BridgeGrandpaCall` used by a chain.
+pub type BridgeGrandpaCallOf<C> = BridgeGrandpaCall<HeaderOf<C>>;
+
+/// Substrate-based chain that is using direct GRANDPA finality.
+///
+/// Keep in mind that parachains are relying on relay chain GRANDPA, so they should not implement
+/// this trait.
+pub trait ChainWithGrandpa: Chain {
+	/// Name of the bridge GRANDPA pallet (used in `construct_runtime` macro call) that is deployed
+	/// at some other chain to bridge with this `ChainWithGrandpa`.
+	///
+	/// We assume that all chains that are bridging with this `ChainWithGrandpa` are using
+	/// the same name.
+	const WITH_CHAIN_GRANDPA_PALLET_NAME: &'static str;
+
+	/// Max number of GRANDPA authorities at the chain.
+	///
+	/// This is a strict constant. If bridged chain will have more authorities than that,
+	/// the GRANDPA bridge pallet may halt.
+	const MAX_AUTHORITIES_COUNT: u32;
+
+	/// Max reasonable number of headers in `votes_ancestries` vector of the GRANDPA justification.
+	///
+	/// This isn't a strict limit. The relay may submit justifications with more headers in its
+	/// ancestry and the pallet will accept such justification. The limit is only used to compute
+	/// maximal refund amount and submitting justifications which exceed the limit, may be costly
+	/// to submitter.
+	const REASONABLE_HEADERS_IN_JUSTIFICATON_ANCESTRY: u32;
+
+	/// Maximal size of the chain header. The header may be the header that enacts new GRANDPA
+	/// authorities set (so it has large digest inside).
+	///
+	/// This isn't a strict limit. The relay may submit larger headers and the pallet will accept
+	/// the call. The limit is only used to compute maximal refund amount and doing calls which
+	/// exceed the limit, may be costly to submitter.
+	const MAX_HEADER_SIZE: u32;
+
+	/// Average size of the chain header from justification ancestry. We don't expect to see there
+	/// headers that change GRANDPA authorities set (GRANDPA will probably be able to finalize at
+	/// least one additional header per session on non test chains), so this is average size of
+	/// headers that aren't changing the set.
+	///
+	/// This isn't a strict limit. The relay may submit justifications with larger headers in its
+	/// ancestry and the pallet will accept the call. The limit is only used to compute maximal
+	/// refund amount and doing calls which exceed the limit, may be costly to submitter.
+	const AVERAGE_HEADER_SIZE_IN_JUSTIFICATION: u32;
+}