Function build_final_state_overrides

crates/simulator/src/encoding.rs:571–679

Resolves all [`AccountOverrideRequest`]s concurrently on a best-effort basis. Returns the fully resolved state overrides and [`AccountOverrideRequest`]s that failed to resolve.

(
    requests: Vec<AccountOverrideRequest>,
    state_overrides: &dyn StateOverriding,
    authenticator: Address,
    settlement_contract: Address,
)

/// basis. Returns the fully resolved state overrides and
/// [`AccountOverrideRequest`]s that failed to resolve.
async fn build_final_state_overrides(
    requests: Vec<AccountOverrideRequest>,
    state_overrides: &dyn StateOverriding,
    authenticator: Address,
    settlement_contract: Address,
) -> (StateOverride, Vec<AccountOverrideRequest>) {
    let futures = requests.into_iter().map(|request| async move {
        let state_override = match &request {
            AccountOverrideRequest::SufficientEthBalance(addr) => Some((
                *addr,
                AccountOverride::default().with_balance(U256::MAX / U256::from(2)),
            )),
            AccountOverrideRequest::AuthenticateAsSolver(addr) => {
                // GPv2AllowListAuthentication stores `mapping(address => bool) solvers`
                // at storage slot 1. Solidity mapping key: keccak256(address_padded ++
                // slot_padded).
                // <https://github.com/cowprotocol/contracts/blob/main/src/contracts/GPv2AllowListAuthentication.sol#L22>
                let mut buf = [0u8; 64];
                buf[12..32].copy_from_slice(addr.as_slice());
                buf[32..64].copy_from_slice(&U256::ONE.to_be_bytes::<32>());
                let slot = keccak256(buf);
                Some((
                    authenticator,
                    AccountOverride::default()
                        .with_state_diff(std::iter::once((slot, B256::with_last_byte(1)))),
                ))
            }
            AccountOverrideRequest::Balance {
                holder,
                token,
                amount,
            } => {
                state_overrides
                    .balance_override(BalanceOverrideRequest {
                        token: *token,
                        holder: *holder,
                        amount: *amount,
                    })
                    .await
            }
            AccountOverrideRequest::Code { account, code } => Some((
                *account,
                AccountOverride {
                    code: Some(code.clone()),
                    ..Default::default()
                },
            )),
            AccountOverrideRequest::PreSignature(order) => {
                // GPv2Settlement stores the `mapping(bytes => uint256) public preSignature` at
                // storage slot 0.
                // Solidity mapping key: keccak256(order_uid_without_padding ++ slot_padded).
                // <https://github.com/cowprotocol/contracts/blob/c6b61ce75841ce4c25ab126def9cc981c568e6c6/src/contracts/mixins/GPv2Signing.sol#L57>
                let mut buf = [0u8; 56 + 32];
                buf[0..56].copy_from_slice(order.0.as_slice());
                // no need to copy anything for storage slot 0 since the array gets 0
                // initialized.
                let slot = keccak256(buf);