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The execute_transaction() function processes Core Lane transactions, validating signatures, nonces, and balances before applying state changes.

​
Basic Execution

use core_lane::{
    execute_transaction, TxEnvelope, Address,
    BundleStateManager, CoreLaneStateForLib, StateManager
};
use anyhow::Result;

fn process_transaction(
    tx: &TxEnvelope,
    sender: Address,
    state: &mut CoreLaneStateForLib,
) -> Result<()> {
    let mut bundle = BundleStateManager::new();
    let block_timestamp = 1704067200; // Unix timestamp
    
    let result = execute_transaction(
        tx,
        sender,
        &mut bundle,
        state,
        block_timestamp
    )?;
    
    if result.success {
        println!("Transaction succeeded!");
        println!("Gas used: {}", result.gas_used);
        
        // Apply changes to state
        let mut state_manager = state.state_manager().clone();
        state_manager.apply_changes(bundle);
        state.replace_state_manager(state_manager);
    } else {
        println!("Transaction failed: {:?}", result.error);
    }
    
    Ok(())
}

​
ExecutionResult

The execute_transaction() function returns an ExecutionResult: 
pub struct ExecutionResult {
    pub success: bool,
    pub gas_used: U256,
    pub gas_refund: U256,
    pub output: Bytes,
    pub logs: Vec<String>,
    pub error: Option<String>,
}

​
Checking Results

let result = execute_transaction(tx, sender, &mut bundle, state, block_timestamp)?;

if result.success {
    println!("✅ Success");
    println!("Gas used: {}", result.gas_used);
    
    for log in &result.logs {
        println!("Log: {}", log);
    }
    
    if !result.output.is_empty() {
        println!("Output: {}", hex::encode(&result.output));
    }
} else {
    eprintln!("❌ Failed: {}", result.error.unwrap_or_default());
    
    for log in &result.logs {
        eprintln!("  {}", log);
    }
}

​
ProcessingContext

The execute_transaction() function requires a type implementing ProcessingContext: 
pub trait ProcessingContext {
    fn state_manager(&self) -> &StateManager;
    fn state_manager_mut(&mut self) -> &mut StateManager;
    fn bitcoin_client_read(&self) -> Option<Arc<dyn BitcoinRpcReadClient>>;
    fn bitcoin_network(&self) -> bitcoin::Network;
    fn handle_cmio_query(
        &mut self,
        message: CmioMessage,
        current_intent_id: Option<B256>,
    ) -> Option<CmioMessage>;
}

​
Using CoreLaneStateForLib

The library provides CoreLaneStateForLib which implements ProcessingContext: 
use core_lane::{
    CoreLaneStateForLib, StateManager,
    create_bitcoin_rpc_client
};
use bitcoin::Network;
use std::sync::Arc;

// Create Bitcoin RPC client
let rpc_client = create_bitcoin_rpc_client(
    "http://127.0.0.1:18443",
    "user",
    "password"
)?;

// Create processing context
let state = StateManager::new();
let mut context = CoreLaneStateForLib::new(
    state,
    rpc_client.clone(),
    rpc_client,
    Network::Regtest
);

// Now you can execute transactions
let mut bundle = BundleStateManager::new();
let result = execute_transaction(
    &tx_envelope,
    sender_address,
    &mut bundle,
    &mut context,
    block_timestamp
)?;

​
Complete Example

Here’s a complete example from examples/simple_sequencer.rs: 
use alloy_consensus::{SignableTransaction, TxEip1559};
use alloy_primitives::{Bytes, TxKind};
use alloy_signer::SignerSync;
use alloy_signer_local::PrivateKeySigner;
use core_lane::{
    create_bitcoin_rpc_client, execute_transaction,
    Address, BundleStateManager, CoreLaneStateForLib,
    StateManager, TxEnvelope, U256,
};
use bitcoin::Network;
use anyhow::Result;

#[tokio::main]
async fn main() -> Result<()> {
    // Setup Bitcoin RPC client
    let bitcoin_client = create_bitcoin_rpc_client(
        "http://127.0.0.1:18443",
        "user",
        "password"
    )?;
    
    // Initialize state and context
    let mut state = StateManager::new();
    let mut state_context = CoreLaneStateForLib::new(
        state.clone(),
        bitcoin_client.clone(),
        bitcoin_client,
        Network::Regtest
    );
    
    // Create a signer
    let signer: PrivateKeySigner =
        "0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80"
            .parse()?;
    let sender = signer.address();
    let recipient = Address::from([0x99; 20]);
    
    // Give sender initial balance
    let mut setup_bundle = BundleStateManager::new();
    let initial_balance = U256::from(10_000_000_000_000_000_000u128);
    setup_bundle.add_balance(&state, sender, initial_balance)?;
    state.apply_changes(setup_bundle);
    state_context.replace_state_manager(state.clone());
    
    // Build transaction
    let tx = TxEip1559 {
        chain_id: 1,
        nonce: 0,
        max_priority_fee_per_gas: 1_000_000_000,
        max_fee_per_gas: 20_000_000_000,
        gas_limit: 21000,
        to: TxKind::Call(recipient),
        value: U256::from(1_000_000_000_000_000_000u128), // 1 ETH
        input: Bytes::new(),
        access_list: Default::default(),
    };
    
    // Sign transaction
    let signature = signer.sign_hash_sync(&tx.signature_hash())?;
    let signed = tx.into_signed(signature);
    let envelope = TxEnvelope::Eip1559(signed);
    
    // Execute transaction
    let mut tx_bundle = BundleStateManager::new();
    let block_timestamp = 1704067200;
    
    let result = execute_transaction(
        &envelope,
        sender,
        &mut tx_bundle,
        &mut state_context,
        block_timestamp
    )?;
    
    if result.success {
        println!("✅ Transaction executed successfully!");
        println!("Gas used: {}", result.gas_used);
        
        // Apply changes
        state.apply_changes(tx_bundle);
        
        println!("Sender balance: {}", state.get_balance(sender));
        println!("Recipient balance: {}", state.get_balance(recipient));
    } else {
        println!("❌ Transaction failed: {:?}", result.error);
    }
    
    Ok(())
}

​
Transaction Helpers

The library provides helper functions for extracting transaction data: 
use core_lane::{get_transaction_input_bytes, get_transaction_nonce};

// Get transaction calldata
let input_bytes = get_transaction_input_bytes(&tx_envelope);
println!("Input: {}", hex::encode(&input_bytes));

// Get transaction nonce
let nonce = get_transaction_nonce(&tx_envelope);
println!("Nonce: {}", nonce);

​
Special Addresses

Core Lane defines special addresses for system operations: 
use core_lane::CoreLaneAddresses;

// Exit marketplace (intent operations)
let exit_marketplace = CoreLaneAddresses::exit_marketplace();
// 0x0000000000000000000000000000000000000045

// Cartesi HTTP runner
let cartesi_runner = CoreLaneAddresses::cartesi_http_runner();
// 0x0000000000000000000000000000000000000042

// Burn address
let burn = CoreLaneAddresses::burn();
// 0x0000000000000000000000000000000000000666
Transactions sent to these addresses trigger special behavior:
  • Exit Marketplace: Intent creation, locking, solving, and cancellation
  • Cartesi HTTP Runner: RISC-V program execution (requires cartesi-runner feature)
  • Burn Address: Reserved for future use

​
Nonce Validation

Transactions are validated for correct nonce sequencing: 
// Transaction with wrong nonce will fail
let result = execute_transaction(tx, sender, &mut bundle, state, block_timestamp)?;

if !result.success {
    // Check for nonce error
    if let Some(error) = &result.error {
        if error.contains("Invalid nonce") {
            println!("Nonce mismatch detected");
        }
    }
}
The nonce must match the account’s current nonce exactly. After successful execution, the nonce is incremented automatically.

​
See Also

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