Merge commit '392447f5c8f986ded2559a78457f4cd87942f393' into update-bridges-subtree-r/w

polkadot/bridges/primitives/token-swap/src/lib.rs

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+// 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/>.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+use codec::{Decode, Encode};
+use frame_support::{weights::Weight, RuntimeDebug};
+use scale_info::TypeInfo;
+use sp_core::U256;
+use sp_std::vec::Vec;
+
+/// Pending token swap state.
+#[derive(Encode, Decode, Clone, RuntimeDebug, PartialEq, Eq, TypeInfo)]
+pub enum TokenSwapState {
+	/// The swap has been started using the `start_claim` call, but we have no proof that it has
+	/// happened at the Bridged chain.
+	Started,
+	/// The swap has happened at the Bridged chain and may be claimed by the Bridged chain party
+	/// using the `claim_swap` call.
+	Confirmed,
+	/// The swap has failed at the Bridged chain and This chain party may cancel it using the
+	/// `cancel_swap` call.
+	Failed,
+}
+
+/// Token swap type.
+///
+/// Different swap types give a different guarantees regarding possible swap
+/// replay protection.
+#[derive(Encode, Decode, Clone, RuntimeDebug, PartialEq, Eq, TypeInfo)]
+pub enum TokenSwapType<ThisBlockNumber> {
+	/// The `target_account_at_bridged_chain` is temporary and only have funds for single swap.
+	///
+	/// ***WARNING**: if `target_account_at_bridged_chain` still exists after the swap has been
+	/// completed (either by claiming or canceling), the `source_account_at_this_chain` will be
+	/// able to restart the swap again and repeat the swap until `target_account_at_bridged_chain`
+	/// depletes.
+	TemporaryTargetAccountAtBridgedChain,
+	/// This swap type prevents `source_account_at_this_chain` from restarting the swap after it
+	/// has been completed. There are two consequences:
+	///
+	/// 1) the `source_account_at_this_chain` won't be able to call `start_swap` after given
+	/// <ThisBlockNumber>; 2) the `target_account_at_bridged_chain` won't be able to call
+	/// `claim_swap` (over the bridge) before    block `<ThisBlockNumber + 1>`.
+	///
+	/// The second element is the nonce of the swap. You must care about its uniqueness if you're
+	/// planning to perform another swap with exactly the same parameters (i.e. same amount, same
+	/// accounts, same `ThisBlockNumber`) to avoid collisions.
+	LockClaimUntilBlock(ThisBlockNumber, U256),
+}
+
+/// An intention to swap `source_balance_at_this_chain` owned by `source_account_at_this_chain`
+/// to `target_balance_at_bridged_chain` owned by `target_account_at_bridged_chain`.
+///
+/// **IMPORTANT NOTE**: this structure is always the same during single token swap. So even
+/// when chain changes, the meaning of This and Bridged are still used to point to the same chains.
+/// This chain is always the chain where swap has been started. And the Bridged chain is the other
+/// chain.
+#[derive(Encode, Decode, Clone, RuntimeDebug, PartialEq, Eq, TypeInfo)]
+pub struct TokenSwap<ThisBlockNumber, ThisBalance, ThisAccountId, BridgedBalance, BridgedAccountId>
+{
+	/// The type of the swap.
+	pub swap_type: TokenSwapType<ThisBlockNumber>,
+	/// This chain balance to be swapped with `target_balance_at_bridged_chain`.
+	pub source_balance_at_this_chain: ThisBalance,
+	/// Account id of the party acting at This chain and owning the `source_account_at_this_chain`.
+	pub source_account_at_this_chain: ThisAccountId,
+	/// Bridged chain balance to be swapped with `source_balance_at_this_chain`.
+	pub target_balance_at_bridged_chain: BridgedBalance,
+	/// Account id of the party acting at the Bridged chain and owning the
+	/// `target_balance_at_bridged_chain`.
+	pub target_account_at_bridged_chain: BridgedAccountId,
+}
+
+/// SCALE-encoded `Currency::transfer` call on the bridged chain.
+pub type RawBridgedTransferCall = Vec<u8>;
+
+/// Token swap creation parameters.
+#[derive(Encode, Decode, Clone, RuntimeDebug, PartialEq, Eq, TypeInfo)]
+pub struct TokenSwapCreation<BridgedAccountPublic, ThisChainBalance, BridgedAccountSignature> {
+	/// Public key of the `target_account_at_bridged_chain` account used to verify
+	/// `bridged_currency_transfer_signature`.
+	pub target_public_at_bridged_chain: BridgedAccountPublic,
+	/// Fee that the `source_account_at_this_chain` is ready to pay for the tokens
+	/// transfer message delivery and dispatch.
+	pub swap_delivery_and_dispatch_fee: ThisChainBalance,
+	/// Specification version of the Bridged chain.
+	pub bridged_chain_spec_version: u32,
+	/// SCALE-encoded tokens transfer call at the Bridged chain.
+	pub bridged_currency_transfer: RawBridgedTransferCall,
+	/// Dispatch weight of the tokens transfer call at the Bridged chain.
+	pub bridged_currency_transfer_weight: Weight,
+	/// The signature of the `target_account_at_bridged_chain` for the message
+	/// returned by the `pallet_bridge_dispatch::account_ownership_digest()` function call.
+	pub bridged_currency_transfer_signature: BridgedAccountSignature,
+}