Relay subcommand that performs token RLT <> MLAU token swap (#1141)

* token swap relay

* token swap subcommand fixes

* fmt

* removed debug traces

* removed commented code

bridges/primitives/runtime/src/lib.rs

@@ -19,7 +19,7 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use codec::Encode;
-use frame_support::RuntimeDebug;
+use frame_support::{RuntimeDebug, StorageHasher};
 use sp_core::{hash::H256, storage::StorageKey};
 use sp_io::hashing::blake2_256;
 use sp_std::{convert::TryFrom, vec::Vec};
@@ -184,6 +184,33 @@ impl<BlockNumber: Copy + Into<u64>, BlockHash: Copy> TransactionEra<BlockNumber,
 	}
 }
 
+/// This is a copypaste of the `frame_support::storage::generator::StorageMap::storage_map_final_key`
+/// for `Blake2_128Concat` maps.
+///
+/// We're using it because to call `storage_map_final_key` directly, we need access to the runtime
+/// and pallet instance, which (sometimes) is impossible.
+pub fn storage_map_final_key_blake2_128concat(pallet_prefix: &str, map_name: &str, key: &[u8]) -> StorageKey {
+	storage_map_final_key_identity(pallet_prefix, map_name, &frame_support::Blake2_128Concat::hash(key))
+}
+
+/// This is a copypaste of the `frame_support::storage::generator::StorageMap::storage_map_final_key`
+/// for `Identity` maps.
+///
+/// We're using it because to call `storage_map_final_key` directly, we need access to the runtime
+/// and pallet instance, which (sometimes) is impossible.
+pub fn storage_map_final_key_identity(pallet_prefix: &str, map_name: &str, key_hashed: &[u8]) -> StorageKey {
+	let pallet_prefix_hashed = frame_support::Twox128::hash(pallet_prefix.as_bytes());
+	let storage_prefix_hashed = frame_support::Twox128::hash(map_name.as_bytes());
+
+	let mut final_key = Vec::with_capacity(pallet_prefix_hashed.len() + storage_prefix_hashed.len() + key_hashed.len());
+
+	final_key.extend_from_slice(&pallet_prefix_hashed[..]);
+	final_key.extend_from_slice(&storage_prefix_hashed[..]);
+	final_key.extend_from_slice(key_hashed.as_ref());
+
+	StorageKey(final_key)
+}
+
 /// This is how a storage key of storage parameter (`parameter_types! { storage Param: bool = false; }`) is computed.
 ///
 /// Copypaste from `frame_support::parameter_types` macro