chore: move withdrawal_requests_contract_call to reth-evm (#9272)

crates/evm/src/system_calls.rs

@@ -1,12 +1,18 @@
 //! System contract call functions.
 
-use alloy_eips::eip4788::BEACON_ROOTS_ADDRESS;
+use crate::ConfigureEvm;
+use alloy_eips::{
+    eip4788::BEACON_ROOTS_ADDRESS,
+    eip7002::{WithdrawalRequest, WITHDRAWAL_REQUEST_PREDEPLOY_ADDRESS},
+};
 use reth_chainspec::{ChainSpec, EthereumHardforks};
 use reth_execution_errors::{BlockExecutionError, BlockValidationError};
+use reth_primitives::{Buf, Request};
 use revm::{interpreter::Host, Database, DatabaseCommit, Evm};
-use revm_primitives::{BlockEnv, CfgEnvWithHandlerCfg, EnvWithHandlerCfg, B256};
-
-use crate::ConfigureEvm;
+use revm_primitives::{
+    Address, BlockEnv, Bytes, CfgEnvWithHandlerCfg, EnvWithHandlerCfg, ExecutionResult, FixedBytes,
+    ResultAndState, B256,
+};
 
 /// Apply the [EIP-4788](https://eips.ethereum.org/EIPS/eip-4788) pre block contract call.
 ///
@@ -123,3 +129,134 @@ where
 
     Ok(())
 }
+
+/// Apply the [EIP-7002](https://eips.ethereum.org/EIPS/eip-7002) post block contract call.
+///
+/// This constructs a new [Evm] with the given DB, and environment
+/// ([`CfgEnvWithHandlerCfg`] and [`BlockEnv`]) to execute the post block contract call.
+///
+/// This uses [`apply_withdrawal_requests_contract_call`] to ultimately calculate the
+/// [requests](Request).
+pub fn post_block_withdrawal_requests_contract_call<EvmConfig, DB>(
+    db: &mut DB,
+    initialized_cfg: &CfgEnvWithHandlerCfg,
+    initialized_block_env: &BlockEnv,
+) -> Result<Vec<Request>, BlockExecutionError>
+where
+    DB: Database + DatabaseCommit,
+    DB::Error: std::fmt::Display,
+    EvmConfig: ConfigureEvm,
+{
+    // apply post-block EIP-7002 contract call
+    let mut evm_post_block = Evm::builder()
+        .with_db(db)
+        .with_env_with_handler_cfg(EnvWithHandlerCfg::new_with_cfg_env(
+            initialized_cfg.clone(),
+            initialized_block_env.clone(),
+            Default::default(),
+        ))
+        .build();
+
+    // initialize a block from the env, because the post block call needs the block itself
+    apply_withdrawal_requests_contract_call::<EvmConfig, _, _>(&mut evm_post_block)
+}
+
+/// Applies the post-block call to the EIP-7002 withdrawal requests contract.
+///
+/// If Prague is not active at the given timestamp, then this is a no-op, and an empty vector is
+/// returned. Otherwise, the withdrawal requests are returned.
+#[inline]
+pub fn apply_withdrawal_requests_contract_call<EvmConfig, EXT, DB>(
+    evm: &mut Evm<'_, EXT, DB>,
+) -> Result<Vec<Request>, BlockExecutionError>
+where
+    DB: Database + DatabaseCommit,
+    DB::Error: core::fmt::Display,
+    EvmConfig: ConfigureEvm,
+{
+    // get previous env
+    let previous_env = Box::new(evm.context.env().clone());
+
+    // Fill transaction environment with the EIP-7002 withdrawal requests contract message data.
+    //
+    // This requirement for the withdrawal requests contract call defined by
+    // [EIP-7002](https://eips.ethereum.org/EIPS/eip-7002) is:
+    //
+    // At the end of processing any execution block where `block.timestamp >= FORK_TIMESTAMP` (i.e.
+    // after processing all transactions and after performing the block body withdrawal requests
+    // validations), call the contract as `SYSTEM_ADDRESS`.
+    EvmConfig::fill_tx_env_system_contract_call(
+        &mut evm.context.evm.env,
+        alloy_eips::eip7002::SYSTEM_ADDRESS,
+        WITHDRAWAL_REQUEST_PREDEPLOY_ADDRESS,
+        Bytes::new(),
+    );
+
+    let ResultAndState { result, mut state } = match evm.transact() {
+        Ok(res) => res,
+        Err(e) => {
+            evm.context.evm.env = previous_env;
+            return Err(BlockValidationError::WithdrawalRequestsContractCall {
+                message: format!("execution failed: {e}"),
+            }
+            .into())
+        }
+    };
+
+    // cleanup the state
+    state.remove(&alloy_eips::eip7002::SYSTEM_ADDRESS);
+    state.remove(&evm.block().coinbase);
+    evm.context.evm.db.commit(state);
+
+    // re-set the previous env
+    evm.context.evm.env = previous_env;
+
+    let mut data = match result {
+        ExecutionResult::Success { output, .. } => Ok(output.into_data()),
+        ExecutionResult::Revert { output, .. } => {
+            Err(BlockValidationError::WithdrawalRequestsContractCall {
+                message: format!("execution reverted: {output}"),
+            })
+        }
+        ExecutionResult::Halt { reason, .. } => {
+            Err(BlockValidationError::WithdrawalRequestsContractCall {
+                message: format!("execution halted: {reason:?}"),
+            })
+        }
+    }?;
+
+    // Withdrawals are encoded as a series of withdrawal requests, each with the following
+    // format:
+    //
+    // +------+--------+--------+
+    // | addr | pubkey | amount |
+    // +------+--------+--------+
+    //    20      48        8
+
+    const WITHDRAWAL_REQUEST_SIZE: usize = 20 + 48 + 8;
+    let mut withdrawal_requests = Vec::with_capacity(data.len() / WITHDRAWAL_REQUEST_SIZE);
+    while data.has_remaining() {
+        if data.remaining() < WITHDRAWAL_REQUEST_SIZE {
+            return Err(BlockValidationError::WithdrawalRequestsContractCall {
+                message: "invalid withdrawal request length".to_string(),
+            }
+            .into())
+        }
+
+        let mut source_address = Address::ZERO;
+        data.copy_to_slice(source_address.as_mut_slice());
+
+        let mut validator_pubkey = FixedBytes::<48>::ZERO;
+        data.copy_to_slice(validator_pubkey.as_mut_slice());
+
+        let amount = data.get_u64();
+
+        withdrawal_requests.push(Request::WithdrawalRequest(WithdrawalRequest {
+            source_address,
+            validator_pubkey,
+            amount,
+        }));
+    }
+
+    Ok(withdrawal_requests)
+}