Rococo (mocky)Runtime and Client (#841)

* Implement fake rococo runtime.

* Generate correct storage key.

* cargo fmt --all

* Move client-rococo.

* Satisfy clippy.

* Apply suggestions from code review

Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>

* Address review comments.

* Clippy again.

Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>

bridges/primitives/chain-rococo/Cargo.toml

@@ -7,6 +7,7 @@ edition = "2018"
 license = "GPL-3.0-or-later WITH Classpath-exception-2.0"
 
 [dependencies]
+parity-scale-codec = { version = "2.0.0", default-features = false, features = ["derive"] }
 
 # Bridge Dependencies
 bp-messages = { path = "../messages", default-features = false }
@@ -14,8 +15,14 @@ bp-polkadot-core = { path = "../polkadot-core", default-features = false }
 bp-runtime = { path = "../runtime", default-features = false }
 
 # Substrate Based Dependencies
+frame-support = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 sp-api = { git = "https://github.com/paritytech/substrate", branch = "master" , default-features = false }
+sp-runtime = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 sp-std = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
+sp-version = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
+
+[dev-dependencies]
+hex = "0.4"
 
 [features]
 default = ["std"]
@@ -23,6 +30,10 @@ std = [
 	"bp-messages/std",
 	"bp-polkadot-core/std",
 	"bp-runtime/std",
+	"frame-support/std",
+	"parity-scale-codec/std",
 	"sp-api/std",
+	"sp-runtime/std",
 	"sp-std/std",
+	"sp-version/std",
 ]

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

@@ -21,10 +21,60 @@
 #![allow(clippy::unnecessary_mut_passed)]
 
 use bp_messages::{LaneId, MessageNonce, UnrewardedRelayersState, Weight};
+use frame_support::{Blake2_128Concat, StorageHasher, Twox128};
 use sp_std::prelude::*;
+use sp_version::RuntimeVersion;
 
 pub use bp_polkadot_core::*;
 
+pub type UncheckedExtrinsic = bp_polkadot_core::UncheckedExtrinsic<Call>;
+
+pub const VERSION: RuntimeVersion = RuntimeVersion {
+	spec_name: sp_version::create_runtime_str!("rococo"),
+	impl_name: sp_version::create_runtime_str!("parity-rococo-v1-1"),
+	authoring_version: 0,
+	spec_version: 30,
+	impl_version: 0,
+	apis: sp_version::create_apis_vec![[]],
+	transaction_version: 6,
+};
+
+#[derive(parity_scale_codec::Encode, parity_scale_codec::Decode, Debug, PartialEq, Eq, Clone)]
+pub enum Call {
+	MockModule,
+}
+
+impl sp_runtime::traits::Dispatchable for Call {
+	type Origin = ();
+	type Config = ();
+	type Info = ();
+	type PostInfo = ();
+
+	fn dispatch(self, _origin: Self::Origin) -> sp_runtime::DispatchResultWithInfo<Self::PostInfo> {
+		unimplemented!("The Call is not expected to be dispatched.")
+	}
+}
+
+/// Return a storage key for account data.
+///
+/// This is based on FRAME storage-generation code from Substrate:
+/// https://github.com/paritytech/substrate/blob/c939ceba381b6313462d47334f775e128ea4e95d/frame/support/src/storage/generator/map.rs#L74
+/// The equivalent command to invoke in case full `Runtime` is known is this:
+/// `let key = frame_system::Account::<Runtime>::storage_map_final_key(&account_id);`
+pub fn account_info_storage_key(id: &AccountId) -> Vec<u8> {
+	let module_prefix_hashed = Twox128::hash(b"System");
+	let storage_prefix_hashed = Twox128::hash(b"Account");
+	let key_hashed = parity_scale_codec::Encode::using_encoded(id, Blake2_128Concat::hash);
+
+	let mut final_key = Vec::with_capacity(module_prefix_hashed.len() + storage_prefix_hashed.len() + key_hashed.len());
+
+	final_key.extend_from_slice(&module_prefix_hashed[..]);
+	final_key.extend_from_slice(&storage_prefix_hashed[..]);
+	final_key.extend_from_slice(&key_hashed);
+
+	final_key
+}
+
 /// Rococo Chain
 pub type Rococo = PolkadotLike;
 
@@ -115,3 +165,19 @@ sp_api::decl_runtime_apis! {
 		fn unrewarded_relayers_state(lane: LaneId) -> UnrewardedRelayersState;
 	}
 }
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	#[test]
+	fn should_generate_storage_key() {
+		let acc = [
+			1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
+			30, 31, 32,
+		]
+		.into();
+		let key = account_info_storage_key(&acc);
+		assert_eq!(hex::encode(key), "26aa394eea5630e07c48ae0c9558cef7b99d880ec681799c0cf30e8886371da92dccd599abfe1920a1cff8a7358231430102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f20");
+	}
+}

bridges/primitives/polkadot-core/Cargo.toml

@@ -7,6 +7,7 @@ edition = "2018"
 license = "GPL-3.0-or-later WITH Classpath-exception-2.0"
 
 [dependencies]
+parity-scale-codec = { version = "2.0.0", default-features = false, features = ["derive"] }
 
 # Bridge Dependencies
 
@@ -21,6 +22,7 @@ sp-api = { git = "https://github.com/paritytech/substrate", branch = "master" ,
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 sp-runtime = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 sp-std = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
+sp-version = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 
 [features]
 default = ["std"]
@@ -29,8 +31,10 @@ std = [
 	"bp-runtime/std",
 	"frame-support/std",
 	"frame-system/std",
+	"parity-scale-codec/std",
 	"sp-api/std",
 	"sp-core/std",
 	"sp-runtime/std",
 	"sp-std/std",
+	"sp-version/std",
 ]

bridges/primitives/polkadot-core/src/lib.rs

@@ -19,6 +19,7 @@
 use bp_messages::MessageNonce;
 use bp_runtime::Chain;
 use frame_support::{
+	dispatch::Dispatchable,
 	parameter_types,
 	weights::{
 		constants::{BlockExecutionWeight, ExtrinsicBaseWeight, WEIGHT_PER_SECOND},
@@ -31,7 +32,7 @@ use sp_core::Hasher as HasherT;
 use sp_runtime::{
 	generic,
 	traits::{BlakeTwo256, IdentifyAccount, Verify},
-	MultiSignature, OpaqueExtrinsic as UncheckedExtrinsic, Perbill,
+	MultiSignature, OpaqueExtrinsic, Perbill,
 };
 
 // Re-export's to avoid extra substrate dependencies in chain-specific crates.
@@ -141,6 +142,12 @@ pub type BlockNumber = u32;
 /// Hash type used in Polkadot-like chains.
 pub type Hash = <BlakeTwo256 as HasherT>::Out;
 
+/// Account Index (a.k.a. nonce).
+pub type Index = u32;
+
+/// Hashing type.
+pub type Hashing = BlakeTwo256;
+
 /// The type of an object that can produce hashes on Polkadot-like chains.
 pub type Hasher = BlakeTwo256;
 
@@ -160,7 +167,7 @@ pub type AccountId = <AccountPublic as IdentifyAccount>::AccountId;
 pub type Nonce = u32;
 
 /// Block type of Polkadot-like chains.
-pub type Block = generic::Block<Header, UncheckedExtrinsic>;
+pub type Block = generic::Block<Header, OpaqueExtrinsic>;
 
 /// Polkadot-like block signed with a Justification.
 pub type SignedBlock = generic::SignedBlock<Block>;
@@ -168,6 +175,86 @@ pub type SignedBlock = generic::SignedBlock<Block>;
 /// The balance of an account on Polkadot-like chain.
 pub type Balance = u128;
 
+/// Unchecked Extrinsic type.
+pub type UncheckedExtrinsic<Call> = generic::UncheckedExtrinsic<AccountId, Call, Signature, SignedExtensions<Call>>;
+
+/// A type of the data encoded as part of the transaction.
+pub type SignedExtra = ((), (), (), sp_runtime::generic::Era, Nonce, (), Balance);
+
+/// Parameters which are part of the payload used to produce transaction signature,
+/// but don't end up in the transaction itself (i.e. inherent part of the runtime).
+pub type AdditionalSigned = (u32, u32, Hash, Hash, (), (), ());
+
+/// A simplified version of signed extensions meant for producing signed transactions
+/// and signed payload in the client code.
+#[derive(PartialEq, Eq, Clone, RuntimeDebug)]
+pub struct SignedExtensions<Call> {
+	encode_payload: SignedExtra,
+	additional_signed: AdditionalSigned,
+	_data: sp_std::marker::PhantomData<Call>,
+}
+
+impl<Call> parity_scale_codec::Encode for SignedExtensions<Call> {
+	fn using_encoded<R, F: FnOnce(&[u8]) -> R>(&self, f: F) -> R {
+		self.encode_payload.using_encoded(f)
+	}
+}
+
+impl<Call> parity_scale_codec::Decode for SignedExtensions<Call> {
+	fn decode<I: parity_scale_codec::Input>(_input: &mut I) -> Result<Self, parity_scale_codec::Error> {
+		unimplemented!("SignedExtensions are never meant to be decoded, they are only used to create transaction");
+	}
+}
+
+impl<Call> SignedExtensions<Call> {
+	pub fn new(
+		version: sp_version::RuntimeVersion,
+		era: sp_runtime::generic::Era,
+		genesis_hash: Hash,
+		nonce: Nonce,
+		tip: Balance,
+	) -> Self {
+		Self {
+			encode_payload: (
+				(),    // spec version
+				(),    // tx version
+				(),    // genesis
+				era,   // era
+				nonce, // nonce (compact encoding)
+				(),    // Check weight
+				tip,   // transaction payment / tip (compact encoding)
+			),
+			additional_signed: (
+				version.spec_version,
+				version.transaction_version,
+				genesis_hash,
+				genesis_hash,
+				(),
+				(),
+				(),
+			),
+			_data: Default::default(),
+		}
+	}
+}
+
+impl<Call> sp_runtime::traits::SignedExtension for SignedExtensions<Call>
+where
+	Call: parity_scale_codec::Codec + sp_std::fmt::Debug + Sync + Send + Clone + Eq + PartialEq,
+	Call: Dispatchable,
+{
+	const IDENTIFIER: &'static str = "Not needed.";
+
+	type AccountId = AccountId;
+	type Call = Call;
+	type AdditionalSigned = AdditionalSigned;
+	type Pre = ();
+
+	fn additional_signed(&self) -> Result<Self::AdditionalSigned, frame_support::unsigned::TransactionValidityError> {
+		Ok(self.additional_signed)
+	}
+}
+
 /// Polkadot-like chain.
 #[derive(RuntimeDebug)]
 pub struct PolkadotLike;