Feat/au precompile (#1080)

* initial config setup

* implement other functions

* add tests

* fmt

* update .sol file

* refactor name

* updated mock

* change interface name, refactor

* remove calldata from interface

* fmt

* update fp-evm

* feat: minor improvements

* feat: apply code suggestions

---------

Co-authored-by: Ashutosh Varma <ashutoshvarma11@live.com>

Cargo.toml

@@ -291,6 +291,7 @@ pallet-evm-precompile-substrate-ecdsa = { path = "./precompiles/substrate-ecdsa"
 pallet-evm-precompile-xcm = { path = "./precompiles/xcm", default-features = false }
 pallet-evm-precompile-xvm = { path = "./precompiles/xvm", default-features = false }
 pallet-evm-precompile-dapps-staking = { path = "./precompiles/dapps-staking", default-features = false }
+pallet-evm-precompile-unified-accounts = { path = "./precompiles/unified-accounts", default-features = false }
 
 pallet-chain-extension-dapps-staking = { path = "./chain-extensions/dapps-staking", default-features = false }
 pallet-chain-extension-xvm = { path = "./chain-extensions/xvm", default-features = false }

precompiles/unified-accounts/Cargo.toml

@@ -0,0 +1,62 @@
+[package]
+name = "pallet-evm-precompile-unified-accounts"
+description = "Evm Precompile for AU"
+version = "0.1.0"
+authors.workspace = true
+edition.workspace = true
+homepage.workspace = true
+repository.workspace = true
+
+[dependencies]
+hex = { workspace = true }
+log = { workspace = true }
+num_enum = { workspace = true }
+precompile-utils = { workspace = true }
+
+# Substrate
+frame-support = { workspace = true }
+frame-system = { workspace = true }
+parity-scale-codec = { workspace = true, features = ["max-encoded-len"] }
+sp-core = { workspace = true }
+sp-io = { workspace = true }
+sp-runtime = { workspace = true }
+sp-std = { workspace = true }
+
+# Frontier
+fp-evm = { workspace = true }
+pallet-evm = { workspace = true }
+pallet-unified-accounts = { workspace = true }
+
+# Astar
+astar-primitives = { workspace = true }
+
+[dev-dependencies]
+derive_more = { workspace = true }
+hex-literal = { workspace = true }
+scale-info = { workspace = true }
+serde = { workspace = true }
+
+precompile-utils = { workspace = true, features = ["testing"] }
+
+ethers = { workspace = true }
+libsecp256k1 = { workspace = true, features = ["hmac", "static-context"] }
+pallet-balances = { workspace = true, features = ["std"] }
+pallet-timestamp = { workspace = true }
+sp-runtime = { workspace = true }
+
+[features]
+default = ["std"]
+std = [
+	"parity-scale-codec/std",
+	"pallet-unified-accounts/std",
+	"fp-evm/std",
+	"frame-support/std",
+	"frame-system/std",
+	"pallet-evm/std",
+	"precompile-utils/std",
+	"sp-core/std",
+	"sp-std/std",
+	"sp-io/std",
+	"sp-runtime/std",
+	"astar-primitives/std",
+]

precompiles/unified-accounts/UnifiedAccounts.sol

@@ -0,0 +1,28 @@
+pragma solidity ^0.8.0;
+
+/**
+ * @title UA interface.
+ */
+
+/// Interface to the precompiled contract
+/// Predeployed at the address 0x0000000000000000000000000000000000005006
+/// For better understanding check the source code:
+/// repo: https://github.com/AstarNetwork/astar
+/// code: pallets/unified-accounts/src/lib.rs
+interface UnifiedAccounts {
+    /// Gets the evm address associated with given account id. If no mapping exists,
+    /// then return the default account id.
+    /// @param accountId: The account id for which you want the evm address for.
+    /// @return (mapped_address, true) if there is a mapping found otherwise (default_address, false)
+    function get_evm_address_or_default(
+        bytes32 accountId
+    ) external view returns (address, bool);
+
+    /// Gets the account id associated with given evm address. If no mapping exists,
+    /// then return the default evm address.
+    /// @param evmAddress: The evm address for which you want the account id for.
+    /// @return (mapped_account, true) if there is a mapping found otherwise (default_account, false)
+    function get_native_address_or_default(
+        address evmAddress
+    ) external view returns (bytes32, bool);
+}

precompiles/unified-accounts/src/lib.rs

@@ -0,0 +1,106 @@
+// This file is part of Astar.
+
+// Copyright (C) 2019-2023 Stake Technologies Pte.Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+// Astar 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.
+
+// Astar 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 Astar. If not, see <http://www.gnu.org/licenses/>.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+use astar_primitives::evm::{UnifiedAddress, UnifiedAddressMapper};
+use core::marker::PhantomData;
+use fp_evm::Precompile;
+use fp_evm::{PrecompileHandle, PrecompileOutput};
+use frame_support::dispatch::Dispatchable;
+use frame_support::traits::IsType;
+use precompile_utils::{
+    succeed, Address, EvmDataWriter, EvmResult, FunctionModifier, PrecompileHandleExt,
+};
+use sp_core::{crypto::AccountId32, H256};
+use sp_std::prelude::*;
+
+#[cfg(test)]
+mod mock;
+#[cfg(test)]
+mod tests;
+
+#[precompile_utils::generate_function_selector]
+#[derive(Debug, PartialEq)]
+pub enum Action {
+    GetEvmAddressOrDefault = "get_evm_address_or_default(bytes32)",
+    GetNativeAddressOrDefault = "get_native_address_or_default(address)",
+}
+
+/// A precompile that expose AU related functions.
+pub struct UnifiedAccountsPrecompile<T, UA>(PhantomData<(T, UA)>);
+
+impl<R, UA> Precompile for UnifiedAccountsPrecompile<R, UA>
+where
+    R: pallet_evm::Config + pallet_unified_accounts::Config,
+    <<R as frame_system::Config>::RuntimeCall as Dispatchable>::RuntimeOrigin:
+        From<Option<R::AccountId>>,
+    <R as frame_system::Config>::AccountId: IsType<AccountId32>,
+    UA: UnifiedAddressMapper<R::AccountId>,
+{
+    fn execute(handle: &mut impl PrecompileHandle) -> EvmResult<PrecompileOutput> {
+        log::trace!(target: "au-precompile", "Execute input = {:?}", handle.input());
+
+        let selector = handle.read_selector()?;
+
+        handle.check_function_modifier(FunctionModifier::View)?;
+
+        match selector {
+            // Dispatchables
+            Action::GetEvmAddressOrDefault => Self::get_evm_address_or_default(handle),
+            Action::GetNativeAddressOrDefault => Self::get_native_address_or_default(handle),
+        }
+    }
+}
+
+impl<R, UA> UnifiedAccountsPrecompile<R, UA>
+where
+    R: pallet_evm::Config + pallet_unified_accounts::Config,
+    <<R as frame_system::Config>::RuntimeCall as Dispatchable>::RuntimeOrigin:
+        From<Option<R::AccountId>>,
+    <R as frame_system::Config>::AccountId: IsType<AccountId32>,
+    UA: UnifiedAddressMapper<R::AccountId>,
+{
+    fn get_evm_address_or_default(
+        handle: &mut impl PrecompileHandle,
+    ) -> EvmResult<PrecompileOutput> {
+        let mut input = handle.read_input()?;
+        input.expect_arguments(1)?;
+        let account_id = AccountId32::new(input.read::<H256>()?.into()).into();
+
+        let output: (Address, bool) = match UA::to_h160_or_default(&account_id) {
+            UnifiedAddress::Mapped(address) => (address.into(), true),
+            UnifiedAddress::Default(address) => (address.into(), false),
+        };
+        Ok(succeed(EvmDataWriter::new().write(output).build()))
+    }
+
+    fn get_native_address_or_default(
+        handle: &mut impl PrecompileHandle,
+    ) -> EvmResult<PrecompileOutput> {
+        let mut input = handle.read_input()?;
+        input.expect_arguments(1)?;
+        let evm_address = input.read::<Address>()?;
+
+        let output: (H256, bool) = match UA::to_account_id_or_default(&evm_address.into()) {
+            UnifiedAddress::Mapped(account_id) => (H256::from(account_id.into().as_ref()), true),
+            UnifiedAddress::Default(account_id) => (H256::from(account_id.into().as_ref()), false),
+        };
+        Ok(succeed(EvmDataWriter::new().write(output).build()))
+    }
+}