feat: add setGasToken precompile

engine-precompiles/src/lib.rs

@@ -15,6 +15,7 @@ pub mod prepaid_gas;
 pub mod promise_result;
 pub mod random;
 pub mod secp256k1;
+pub mod set_gas_token;
 mod utils;
 pub mod xcc;
 
@@ -111,8 +112,8 @@ impl HardFork for Istanbul {}
 impl HardFork for Berlin {}
 
 pub struct Precompiles<'a, I, E, H> {
-    pub all_precompiles: prelude::BTreeMap<Address, AllPrecompiles<'a, I, E, H>>,
-    pub paused_precompiles: prelude::BTreeSet<Address>,
+    pub all_precompiles: BTreeMap<Address, AllPrecompiles<'a, I, E, H>>,
+    pub paused_precompiles: BTreeSet<Address>,
 }
 
 impl<'a, I, E, H> Precompiles<'a, I, E, H> {
@@ -149,7 +150,7 @@ impl<'a, I: IO + Copy, E: Env, H: ReadOnlyPromiseHandler> executor::stack::Preco
         Some(result.and_then(|output| post_process(output, handle)))
     }
 
-    fn is_precompile(&self, address: prelude::H160) -> bool {
+    fn is_precompile(&self, address: H160) -> bool {
         self.all_precompiles.contains_key(&Address::new(address))
     }
 }
@@ -270,7 +271,7 @@ impl<'a, I: IO + Copy, E: Env, H: ReadOnlyPromiseHandler> Precompiles<'a, I, E,
             RandomSeed::ADDRESS,
             CurrentAccount::ADDRESS,
         ];
-        let fun: prelude::Vec<Box<dyn Precompile>> = vec![
+        let fun: Vec<Box<dyn Precompile>> = vec![
             Box::new(ECRecover),
             Box::new(SHA256),
             Box::new(RIPEMD160),
@@ -386,10 +387,10 @@ pub enum AllPrecompiles<'a, I, E, H> {
 /// fn for making an address by concatenating the bytes from two given numbers,
 /// Note that 32 + 128 = 160 = 20 bytes (the length of an address). This function is used
 /// as a convenience for specifying the addresses of the various precompiles.
-pub const fn make_address(x: u32, y: u128) -> prelude::types::Address {
+pub const fn make_address(x: u32, y: u128) -> Address {
     let x_bytes = x.to_be_bytes();
     let y_bytes = y.to_be_bytes();
-    prelude::types::Address::new(H160([
+    Address::new(H160([
         x_bytes[0],
         x_bytes[1],
         x_bytes[2],
@@ -413,10 +414,10 @@ pub const fn make_address(x: u32, y: u128) -> prelude::types::Address {
     ]))
 }
 
-const fn make_h256(x: u128, y: u128) -> prelude::H256 {
+const fn make_h256(x: u128, y: u128) -> H256 {
     let x_bytes = x.to_be_bytes();
     let y_bytes = y.to_be_bytes();
-    prelude::H256([
+    H256([
         x_bytes[0],
         x_bytes[1],
         x_bytes[2],

engine-precompiles/src/set_gas_token.rs

@@ -0,0 +1,157 @@
+use crate::set_gas_token::events::SetGasTokenLog;
+use crate::{EvmPrecompileResult, Precompile, PrecompileOutput};
+use aurora_engine_types::types::{Address, EthGas};
+use evm::backend::Log;
+use evm::{Context, ExitError};
+use std::borrow::Cow;
+
+pub use consts::SET_GAS_TOKEN_ADDRESS;
+
+mod costs {
+    use crate::prelude::types::EthGas;
+
+    // TODO: gas costs, could be calculated returning logs of NEAR gas used prior and after.
+    // Should check if the gas check adds gas itself as well..?
+    pub(super) const SET_GAS_TOKEN_GAS: EthGas = EthGas::new(0);
+}
+
+pub mod consts {
+    use aurora_engine_types::types::Address;
+
+    /// Change gas token precompile address.
+    ///
+    /// Address: `0x076dae45c8e16a92258252fe04dedd97f1ea93d6`
+    ///
+    /// This address is computed as: `keccak("setGasToken")[12..]`
+    pub const SET_GAS_TOKEN_ADDRESS: Address =
+        crate::make_address(0x076dae45, 0xc8e16a92258252fe04dedd97f1ea93d6);
+}
+
+pub mod events {
+    use crate::set_gas_token::consts;
+    use aurora_engine_types::types::Address;
+    use aurora_engine_types::H256;
+    use evm::backend::Log;
+
+    // TODO
+    pub(crate) const SET_GAS_TOKEN_SIGNATURE: H256 = crate::make_h256(
+        0x29d0b6eaa171d0d1607729f506329510,
+        0x7bc9766ba17d250f129cb5bd06503d13,
+    );
+
+    pub(crate) struct SetGasTokenLog {
+        pub sender: Address,
+        pub gas_token: Address,
+    }
+
+    impl SetGasTokenLog {
+        pub(crate) fn encode(self) -> Log {
+            let data = ethabi::encode(&[ethabi::Token::Address(self.gas_token.raw())]);
+            let sender_address = {
+                let mut buf = [0u8; 32];
+                buf[12..].copy_from_slice(self.sender.as_bytes());
+                H256(buf)
+            };
+            let topics = vec![SET_GAS_TOKEN_SIGNATURE, sender_address];
+
+            let raw_log = ethabi::RawLog { topics, data };
+
+            Log {
+                address: consts::SET_GAS_TOKEN_ADDRESS.raw(),
+                topics: raw_log.topics,
+                data: raw_log.data,
+            }
+        }
+    }
+
+    #[cfg(test)]
+    pub fn set_gas_token_schema() -> ethabi::Event {
+        ethabi::Event {
+            name: "SetGasToken".into(),
+            inputs: vec![
+                ethabi::EventParam {
+                    name: "sender".into(),
+                    kind: ethabi::ParamType::Address,
+                    indexed: true,
+                },
+                ethabi::EventParam {
+                    name: "gas_token".into(),
+                    kind: ethabi::ParamType::Address,
+                    indexed: true,
+                },
+            ],
+            anonymous: false,
+        }
+    }
+}
+
+/// A precompile contract used to set the gas token.
+///
+/// Takes an input which must be an approved ERC-20 contract, or ETH itself at
+/// the address `0x0`.
+pub struct SetGasToken;
+
+impl SetGasToken {
+    pub const ADDRESS: Address = SET_GAS_TOKEN_ADDRESS;
+}
+
+impl Precompile for SetGasToken {
+    fn required_gas(_input: &[u8]) -> Result<EthGas, ExitError> {
+        Ok(costs::SET_GAS_TOKEN_GAS)
+    }
+
+    fn run(
+        &self,
+        input: &[u8],
+        target_gas: Option<EthGas>,
+        context: &Context,
+        is_static: bool,
+    ) -> EvmPrecompileResult {
+        let required_gas = Self::required_gas(input)?;
+        if let Some(target_gas) = target_gas {
+            if required_gas > target_gas {
+                return Err(ExitError::OutOfGas);
+            }
+        }
+
+        // It's not allowed to call exit precompiles in static mode
+        if is_static {
+            return Err(ExitError::Other(Cow::from("ERR_INVALID_IN_STATIC")));
+        } else if context.address != Self::ADDRESS.raw() {
+            return Err(ExitError::Other(Cow::from("ERR_INVALID_IN_DELEGATE")));
+        }
+
+        let set_gas_token_log: Log = {
+            let sender = Address::new(context.caller);
+            let gas_token = Address::try_from_slice(input)
+                .map_err(|_e| ExitError::Other(Cow::from("ERR_INVALID_ETH_ADDRESS")))?;
+            SetGasTokenLog { sender, gas_token }.encode()
+        };
+
+        Ok(PrecompileOutput {
+            cost: required_gas,
+            logs: vec![set_gas_token_log],
+            ..Default::default()
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use aurora_engine_sdk::types::near_account_to_evm_address;
+
+    #[test]
+    fn test_precompile_id() {
+        assert_eq!(
+            SET_GAS_TOKEN_ADDRESS,
+            near_account_to_evm_address("setGasToken".as_bytes())
+        );
+    }
+
+    #[test]
+    fn test_signature() {
+        let schema = events::set_gas_token_schema();
+        assert_eq!(schema.signature(), events::SET_GAS_TOKEN_SIGNATURE);
+    }
+}

engine-types/src/types/address.rs

@@ -4,6 +4,9 @@ use borsh::{BorshDeserialize, BorshSerialize};
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 
+const ADDRESS_HEX_LENGTH: usize = 40;
+const ADDRESS_BYTE_LENGTH: usize = 20;
+
 /// Base Eth Address type
 #[derive(Debug, Clone, Copy, Eq, PartialEq, Ord, PartialOrd)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
@@ -26,10 +29,10 @@ impl Address {
     }
 
     pub fn decode(address: &str) -> Result<Address, error::AddressError> {
-        if address.len() != 40 {
+        if address.len() != ADDRESS_HEX_LENGTH {
             return Err(error::AddressError::IncorrectLength);
         }
-        let mut result = [0u8; 20];
+        let mut result = [0u8; ADDRESS_BYTE_LENGTH];
         hex::decode_to_slice(address, &mut result)
             .map_err(|_| error::AddressError::FailedDecodeHex)?;
         Ok(Address::new(H160(result)))
@@ -40,18 +43,25 @@ impl Address {
     }
 
     pub fn try_from_slice(raw_addr: &[u8]) -> Result<Self, error::AddressError> {
-        if raw_addr.len() != 20 {
-            return Err(error::AddressError::IncorrectLength);
+        use core::cmp::Ordering;
+        match raw_addr.len().cmp(&ADDRESS_BYTE_LENGTH) {
+            Ordering::Greater => Err(error::AddressError::IncorrectLength),
+            Ordering::Less => {
+                let mut buf = [0u8; ADDRESS_BYTE_LENGTH];
+                let pos = ADDRESS_BYTE_LENGTH - raw_addr.len();
+                buf[pos..].copy_from_slice(raw_addr);
+                Ok(Self::new(H160::from_slice(&buf)))
+            }
+            Ordering::Equal => Ok(Self::new(H160::from_slice(raw_addr))),
         }
-        Ok(Self::new(H160::from_slice(raw_addr)))
     }
 
-    pub const fn from_array(array: [u8; 20]) -> Self {
+    pub const fn from_array(array: [u8; ADDRESS_BYTE_LENGTH]) -> Self {
         Self(H160(array))
     }
 
     pub const fn zero() -> Self {
-        Address::new(H160([0u8; 20]))
+        Address::new(H160([0u8; ADDRESS_BYTE_LENGTH]))
     }
 }
 
@@ -71,15 +81,15 @@ impl BorshSerialize for Address {
 
 impl BorshDeserialize for Address {
     fn deserialize(buf: &mut &[u8]) -> io::Result<Self> {
-        if buf.len() < 20 {
+        if buf.len() < ADDRESS_BYTE_LENGTH {
             return Err(io::Error::new(
                 io::ErrorKind::Other,
                 format!("{}", error::AddressError::IncorrectLength),
             ));
         }
         // Guaranty no panics. The length checked early
-        let address = Self(H160::from_slice(&buf[..20]));
-        *buf = &buf[20..];
+        let address = Self(H160::from_slice(&buf[..ADDRESS_BYTE_LENGTH]));
+        *buf = &buf[ADDRESS_BYTE_LENGTH..];
         Ok(address)
     }
 }
@@ -139,8 +149,19 @@ mod tests {
     }
 
     #[test]
-    fn test_wrong_address_19() {
-        let serialized_addr = [0u8; 19];
+    fn test_address_less_than_20_byte_length() {
+        let serialized_addr = [0x1u8; 1];
+        let addr = Address::try_from_slice(&serialized_addr).unwrap();
+        let expected = Address::try_from_slice(
+            &hex::decode("0000000000000000000000000000000000000001").unwrap(),
+        )
+        .unwrap();
+        assert_eq!(addr, expected);
+    }
+
+    #[test]
+    fn test_address_greater_than_20_byte_length() {
+        let serialized_addr = [0x11u8; 21];
         let addr = Address::try_from_slice(&serialized_addr);
         let err = addr.unwrap_err();
         matches!(err, error::AddressError::IncorrectLength);

engine-types/src/types/gas.rs

@@ -56,6 +56,8 @@ impl Display for EthGas {
 }
 
 impl EthGas {
+    pub const MAX: EthGas = EthGas(u64::MAX);
+
     /// Constructs a new `EthGas` with a given u64 value.
     pub const fn new(gas: u64) -> EthGas {
         Self(gas)