Struct TradeSimulator 

pub struct TradeSimulator { /* private fields */ }

Simulates settlement execution to estimate gas costs and detect reverts.

Wraps a reqwest::Client targeting a JSON-RPC endpoint and the canonical GPv2Settlement contract on a specific chain.

Example

use cow_chains::SupportedChainId;
use cow_settlement::simulator::TradeSimulator;

let sim = TradeSimulator::new("https://rpc.sepolia.org", SupportedChainId::Sepolia);

Implementations

impl TradeSimulator

pub fn new( rpc_url: impl Into<String>, chain: SupportedChainId, ) -> TradeSimulator

Create a new trade simulator for the given chain.

Uses the canonical GPv2Settlement contract address for chain.

Arguments

• rpc_url - The JSON-RPC endpoint URL.
• chain - The target SupportedChainId.

Returns

A new TradeSimulator configured for the specified chain.

pub const fn settlement_address(&self) -> Address

Return the settlement contract address this simulator targets.

Returns

The settlement contract Address.

pub fn rpc_url(&self) -> &str

Return the RPC URL this simulator is configured to use.

Returns

A reference to the RPC URL string.

pub async fn estimate_gas(&self, calldata: &[u8]) -> Result<u64, CowError>

Estimate the gas cost of executing calldata against the settlement contract.

Sends an eth_estimateGas JSON-RPC request with the provided calldata targeting the settlement contract.

Arguments

• calldata - The ABI-encoded calldata to estimate gas for.

Returns

The estimated gas as u64.

Errors

Returns CowError::Rpc if the RPC request fails or the node returns an error (e.g., the transaction would revert).

pub async fn simulate( &self, calldata: &[u8], ) -> Result<SimulationResult, CowError>

Simulate executing calldata against the settlement contract via eth_call.

Unlike estimate_gas, this method does not fail on reverts — instead it returns a SimulationResult indicating whether the call succeeded or reverted.

Arguments

• calldata - The ABI-encoded calldata to simulate.

Returns

A SimulationResult with success status, gas estimate, and return data.

Errors

Returns CowError::Rpc only on transport-level failures (HTTP errors). Execution reverts are captured in the returned SimulationResult.

pub async fn estimate_settlement( &self, encoder: &SettlementEncoder, ) -> Result<u64, CowError>

Convenience method: encode a settlement and estimate its gas cost.

Combines SettlementEncoder::encode_settlement with estimate_gas.

Arguments

• encoder - The SettlementEncoder containing the settlement to estimate.

Returns

The estimated gas as u64.

Errors

Returns CowError::Rpc if the RPC request fails or the settlement would revert.

Trait Implementations

impl Clone for TradeSimulator

fn clone(&self) -> TradeSimulator

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for TradeSimulator

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.