miden_tx/executor/

mod.rs

use alloc::boxed::Box;
use alloc::collections::BTreeSet;
use alloc::sync::Arc;
use core::marker::PhantomData;

use miden_processor::advice::AdviceInputs;
use miden_processor::{ExecutionError, FastProcessor, StackInputs};
pub use miden_processor::{ExecutionOptions, MastForestStore, ProgramExecutor};
use miden_protocol::account::AccountId;
use miden_protocol::assembly::DefaultSourceManager;
use miden_protocol::assembly::debuginfo::SourceManagerSync;
use miden_protocol::asset::{Asset, AssetId};
use miden_protocol::block::BlockNumber;
use miden_protocol::transaction::{
    ExecutedTransaction,
    InputNote,
    InputNotes,
    TransactionArgs,
    TransactionInputs,
    TransactionKernel,
    TransactionScript,
};
use miden_protocol::vm::StackOutputs;
use miden_protocol::{Felt, MAX_TX_EXECUTION_CYCLES, MIN_TX_EXECUTION_CYCLES};

use super::TransactionExecutorError;
use crate::auth::TransactionAuthenticator;
use crate::errors::TransactionKernelError;
use crate::host::{AccountProcedureIndexMap, ScriptMastForestStore};

mod exec_host;
pub use exec_host::TransactionExecutorHost;

mod data_store;
pub use data_store::DataStore;

mod notes_checker;
pub use notes_checker::{
    FailedNote,
    MAX_NUM_CHECKER_NOTES,
    NoteConsumptionChecker,
    NoteConsumptionInfo,
    NoteFailure,
    SuccessfulNote,
};

// TRANSACTION EXECUTOR
// ================================================================================================

/// The transaction executor is responsible for executing Miden blockchain transactions.
///
/// Transaction execution consists of the following steps:
/// - Fetch the data required to execute a transaction from the [DataStore].
/// - Execute the transaction program and create an [ExecutedTransaction].
///
/// The transaction executor uses dynamic dispatch with trait objects for the [DataStore] and
/// [TransactionAuthenticator], allowing it to be used with different backend implementations.
/// At the moment of execution, the [DataStore] is expected to provide all required MAST nodes.
pub struct TransactionExecutor<
    'store,
    'auth,
    STORE: 'store,
    AUTH: 'auth,
    EXEC: ProgramExecutor = FastProcessor,
> {
    data_store: &'store STORE,
    authenticator: Option<&'auth AUTH>,
    source_manager: Arc<dyn SourceManagerSync>,
    exec_options: ExecutionOptions,
    _executor: PhantomData<EXEC>,
}

impl<'store, 'auth, STORE, AUTH> TransactionExecutor<'store, 'auth, STORE, AUTH>
where
    STORE: DataStore + 'store + Sync,
    AUTH: TransactionAuthenticator + 'auth + Sync,
{
    // CONSTRUCTORS
    // --------------------------------------------------------------------------------------------

    /// Creates a new [TransactionExecutor] instance with the specified [DataStore].
    ///
    /// The created executor will not have the authenticator or source manager set, and tracing and
    /// debug mode will be turned off.
    ///
    /// By default, the executor uses [`FastProcessor`](miden_processor::FastProcessor) for program
    /// execution. Use [`with_program_executor`](Self::with_program_executor) to plug in a
    /// different execution engine.
    pub fn new(data_store: &'store STORE) -> Self {
        const _: () = assert!(MIN_TX_EXECUTION_CYCLES <= MAX_TX_EXECUTION_CYCLES);
        Self {
            data_store,
            authenticator: None,
            source_manager: Arc::new(DefaultSourceManager::default()),
            exec_options: ExecutionOptions::new(
                Some(MAX_TX_EXECUTION_CYCLES),
                MIN_TX_EXECUTION_CYCLES,
                ExecutionOptions::DEFAULT_CORE_TRACE_FRAGMENT_SIZE,
            )
            .expect("Must not fail while max cycles is more than min trace length"),
            _executor: PhantomData,
        }
    }
}

impl<'store, 'auth, STORE, AUTH, EXEC> TransactionExecutor<'store, 'auth, STORE, AUTH, EXEC>
where
    STORE: DataStore + 'store + Sync,
    AUTH: TransactionAuthenticator + 'auth + Sync,
    EXEC: ProgramExecutor,
{
    /// Replaces the transaction program executor with a different implementation.
    ///
    /// This allows plugging in alternative execution engines while preserving the rest of the
    /// transaction executor configuration.
    pub fn with_program_executor<EXEC2: ProgramExecutor>(
        self,
    ) -> TransactionExecutor<'store, 'auth, STORE, AUTH, EXEC2> {
        TransactionExecutor::<'store, 'auth, STORE, AUTH, EXEC2> {
            data_store: self.data_store,
            authenticator: self.authenticator,
            source_manager: self.source_manager,
            exec_options: self.exec_options,
            _executor: PhantomData,
        }
    }

    /// Adds the specified [TransactionAuthenticator] to the executor and returns the resulting
    /// executor.
    ///
    /// This will overwrite any previously set authenticator.
    #[must_use]
    pub fn with_authenticator(mut self, authenticator: &'auth AUTH) -> Self {
        self.authenticator = Some(authenticator);
        self
    }

    /// Adds the specified source manager to the executor and returns the resulting executor.
    ///
    /// The `source_manager` is used to map potential errors back to their source code. To get the
    /// most value out of it, use the same source manager as was used with the
    /// [`Assembler`](miden_protocol::assembly::Assembler) that assembled the Miden Assembly code
    /// that should be debugged, e.g. account components, note scripts or transaction scripts.
    ///
    /// This will overwrite any previously set source manager.
    #[must_use]
    pub fn with_source_manager(mut self, source_manager: Arc<dyn SourceManagerSync>) -> Self {
        self.source_manager = source_manager;
        self
    }

    /// Sets the [ExecutionOptions] for the executor to the provided options and returns the
    /// resulting executor.
    ///
    /// # Errors
    /// Returns an error if the specified cycle values (`max_cycles` and `expected_cycles`) in
    /// the [ExecutionOptions] are not within the range [`MIN_TX_EXECUTION_CYCLES`] and
    /// [`MAX_TX_EXECUTION_CYCLES`].
    pub fn with_options(
        mut self,
        exec_options: ExecutionOptions,
    ) -> Result<Self, TransactionExecutorError> {
        validate_num_cycles(exec_options.max_cycles())?;
        validate_num_cycles(exec_options.expected_cycles())?;

        self.exec_options = exec_options;
        Ok(self)
    }

    // TRANSACTION EXECUTION
    // --------------------------------------------------------------------------------------------

    /// Prepares and executes a transaction specified by the provided arguments and returns an
    /// [`ExecutedTransaction`].
    ///
    /// The method first fetches the data required to execute the transaction from the [`DataStore`]
    /// and compile the transaction into an executable program. In particular, it fetches the
    /// account identified by the account ID from the store as well as `block_ref`, the header of
    /// the reference block of the transaction and the set of headers from the blocks in which the
    /// provided `notes` were created. Then, it executes the transaction program and creates an
    /// [`ExecutedTransaction`].
    ///
    /// # Errors:
    ///
    /// Returns an error if:
    /// - If required data can not be fetched from the [`DataStore`].
    /// - If the transaction arguments contain foreign account data not anchored in the reference
    ///   block.
    /// - If any input notes were created in block numbers higher than the reference block.
    pub async fn execute_transaction(
        &self,
        account_id: AccountId,
        block_ref: BlockNumber,
        notes: InputNotes<InputNote>,
        tx_args: TransactionArgs,
    ) -> Result<ExecutedTransaction, TransactionExecutorError> {
        let tx_inputs = self.prepare_tx_inputs(account_id, block_ref, notes, tx_args).await?;

        let (mut host, stack_inputs, advice_inputs) = self.prepare_transaction(&tx_inputs).await?;

        // Use the package-debug execution API even when the embedded release kernel has no debug
        // sections. This enables package-owned debug info for dynamically loaded scripts.
        let program = TransactionKernel::main();
        let kernel_debug_info = TransactionKernel::main_debug_info();
        let processor = EXEC::new(stack_inputs, advice_inputs, self.exec_options)
            .map_err(ExecutionError::advice_error_no_context)
            .map_err(map_execution_error)?
            .with_debug_info(kernel_debug_info.as_deref().cloned().unwrap_or_default())
            .with_entrypoint_source_node(TransactionKernel::main_entrypoint_source_node());
        let output = processor.execute(&program, &mut host).await.map_err(map_execution_error)?;
        let stack_outputs = output.stack;
        let advice_provider = output.advice;

        // The stack is not necessary since it is being reconstructed when re-executing.
        let (_stack, advice_map, merkle_store) = advice_provider.into_parts();
        let advice_inputs = AdviceInputs::from(advice_map).with_merkle_store(merkle_store);

        build_executed_transaction(advice_inputs, tx_inputs, stack_outputs, host)
    }

    // SCRIPT EXECUTION
    // --------------------------------------------------------------------------------------------

    /// Executes an arbitrary script against the given account and returns the stack state at the
    /// end of execution.
    ///
    /// # Errors:
    /// Returns an error if:
    /// - If required data can not be fetched from the [DataStore].
    /// - If the transaction host can not be created from the provided values.
    /// - If the execution of the provided program fails.
    pub async fn execute_tx_view_script(
        &self,
        account_id: AccountId,
        block_ref: BlockNumber,
        tx_script: TransactionScript,
        advice_inputs: AdviceInputs,
    ) -> Result<[Felt; 16], TransactionExecutorError> {
        let mut tx_args = TransactionArgs::default().with_tx_script(tx_script);
        tx_args.extend_advice_inputs(advice_inputs);

        let notes = InputNotes::default();
        let tx_inputs = self.prepare_tx_inputs(account_id, block_ref, notes, tx_args).await?;

        let (mut host, stack_inputs, advice_inputs) = self.prepare_transaction(&tx_inputs).await?;

        let program = TransactionKernel::tx_script_main();
        let kernel_debug_info = TransactionKernel::tx_script_main_debug_info();
        let processor =
            EXEC::new(stack_inputs, advice_inputs, self.exec_options)
                .map_err(ExecutionError::advice_error_no_context)
                .map_err(TransactionExecutorError::TransactionProgramExecutionFailed)?
                .with_debug_info(kernel_debug_info.as_deref().cloned().unwrap_or_default())
                .with_entrypoint_source_node(
                    TransactionKernel::tx_script_main_entrypoint_source_node(),
                );
        let output = processor
            .execute(&program, &mut host)
            .await
            .map_err(TransactionExecutorError::TransactionProgramExecutionFailed)?;
        let stack_outputs = output.stack;

        Ok(*stack_outputs)
    }

    // HELPER METHODS
    // --------------------------------------------------------------------------------------------

    // Validates input notes and account inputs after retrieving transaction inputs from the store.
    //
    // This method has a one-to-many call relationship with the `prepare_transaction` method. This
    // method needs to be called only once in order to allow many transactions to be prepared based
    // on the transaction inputs returned by this method.
    async fn prepare_tx_inputs(
        &self,
        account_id: AccountId,
        block_ref: BlockNumber,
        input_notes: InputNotes<InputNote>,
        tx_args: TransactionArgs,
    ) -> Result<TransactionInputs, TransactionExecutorError> {
        let (mut asset_ids, mut ref_blocks) = validate_input_notes(&input_notes, block_ref)?;
        ref_blocks.insert(block_ref);

        let (account, block_header, protocol_config, blockchain) = self
            .data_store
            .get_transaction_inputs(account_id, ref_blocks)
            .await
            .map_err(TransactionExecutorError::FetchTransactionInputsFailed)?;

        let native_account_vault_root = account.vault().root();

        let mut tx_inputs =
            TransactionInputs::new(account, block_header, protocol_config, blockchain, input_notes)
                .map_err(TransactionExecutorError::InvalidTransactionInputs)?
                .with_tx_args(tx_args);

        // filter out any asset IDs for which we already have witnesses in the advice inputs
        asset_ids.retain(|asset_id| {
            !tx_inputs.has_vault_asset_witness(native_account_vault_root, asset_id)
        });

        // if any of the witnesses are missing, fetch them from the data store and add to tx_inputs
        if !asset_ids.is_empty() {
            let asset_witnesses = self
                .data_store
                .get_vault_asset_witnesses(account_id, native_account_vault_root, asset_ids)
                .await
                .map_err(TransactionExecutorError::FetchAssetWitnessFailed)?;

            tx_inputs = tx_inputs.with_asset_witnesses(asset_witnesses);
        }

        Ok(tx_inputs)
    }

    /// Prepares the data needed for transaction execution.
    ///
    /// Preparation includes loading transaction inputs from the data store, validating them, and
    /// instantiating a transaction host.
    async fn prepare_transaction(
        &self,
        tx_inputs: &TransactionInputs,
    ) -> Result<
        (TransactionExecutorHost<'store, 'auth, STORE, AUTH>, StackInputs, AdviceInputs),
        TransactionExecutorError,
    > {
        let (stack_inputs, tx_advice_inputs) = TransactionKernel::prepare_inputs(tx_inputs);
        let input_notes = tx_inputs.input_notes();

        let script_mast_store = ScriptMastForestStore::new(
            tx_inputs.tx_script(),
            input_notes.iter().map(|n| n.note().script()),
        );

        // To start executing the transaction, the procedure index map only needs to contain the
        // native account's procedures. Foreign accounts are inserted into the map on first access.
        let account_procedure_index_map =
            AccountProcedureIndexMap::new([tx_inputs.account().code()]);

        let host = TransactionExecutorHost::new(
            tx_inputs.account(),
            input_notes.clone(),
            self.data_store,
            script_mast_store,
            account_procedure_index_map,
            self.authenticator,
            tx_inputs.block_header().block_num(),
            tx_inputs.collect_block_commitments(),
            self.source_manager.clone(),
        )
        .map_err(|err| TransactionExecutorError::TransactionHostCreationFailed(Box::new(err)))?;

        let advice_inputs = tx_advice_inputs.into_advice_inputs();

        Ok((host, stack_inputs, advice_inputs))
    }
}

// HELPER FUNCTIONS
// ================================================================================================

/// Creates a new [ExecutedTransaction] from the provided data.
fn build_executed_transaction<STORE: DataStore + Sync, AUTH: TransactionAuthenticator + Sync>(
    mut advice_inputs: AdviceInputs,
    tx_inputs: TransactionInputs,
    stack_outputs: StackOutputs,
    host: TransactionExecutorHost<STORE, AUTH>,
) -> Result<ExecutedTransaction, TransactionExecutorError> {
    let (
        account_patch,
        _input_notes,
        output_notes,
        accessed_foreign_account_code,
        generated_signatures,
        tx_progress,
        foreign_account_slot_names,
    ) = host.into_parts();

    let tx_outputs =
        TransactionKernel::from_transaction_parts(&stack_outputs, &advice_inputs, output_notes)
            .map_err(TransactionExecutorError::TransactionOutputConstructionFailed)?;

    let patch_commitment = account_patch.to_commitment();
    if tx_outputs.account_patch_commitment() != patch_commitment {
        return Err(TransactionExecutorError::InconsistentAccountPatchCommitment {
            in_kernel_commitment: tx_outputs.account_patch_commitment(),
            host_commitment: patch_commitment,
        });
    }

    let initial_account = tx_inputs.account();
    let final_account = tx_outputs.account();

    if initial_account.id() != final_account.id() {
        return Err(TransactionExecutorError::InconsistentAccountId {
            input_id: initial_account.id(),
            output_id: final_account.id(),
        });
    }

    // Introduce generated signatures into the witness inputs.
    advice_inputs.extend(AdviceInputs::default().with_map(generated_signatures));

    // Overwrite advice inputs from after the execution on the transaction inputs. This is
    // guaranteed to be a superset of the original advice inputs.
    let tx_inputs = tx_inputs
        .with_foreign_account_code(accessed_foreign_account_code)
        .with_foreign_account_slot_names(foreign_account_slot_names)
        .with_advice_inputs(advice_inputs);

    Ok(ExecutedTransaction::new(
        tx_inputs,
        tx_outputs,
        account_patch,
        tx_progress.into(),
    ))
}

/// Validates that input notes were not created after the reference block.
///
/// Returns the set of block numbers required to execute the provided notes and the set of asset
/// asset IDs that will be needed in the transaction prologue.
///
/// The transaction input vault is a copy of the account vault and to mutate the input vault (during
/// the prologue, for asset preservation), witnesses for the note assets against the account vault
/// must be requested.
fn validate_input_notes(
    notes: &InputNotes<InputNote>,
    block_ref: BlockNumber,
) -> Result<(BTreeSet<AssetId>, BTreeSet<BlockNumber>), TransactionExecutorError> {
    let mut ref_blocks: BTreeSet<BlockNumber> = BTreeSet::new();
    let mut asset_ids: BTreeSet<AssetId> = BTreeSet::new();

    for input_note in notes.iter() {
        // Validate that notes were not created after the reference, and build the set of required
        // block numbers
        if let Some(location) = input_note.location() {
            if location.block_num() > block_ref {
                return Err(TransactionExecutorError::NoteBlockPastReferenceBlock(
                    input_note.id(),
                    block_ref,
                ));
            }
            ref_blocks.insert(location.block_num());
        }

        asset_ids.extend(input_note.note().assets().iter().map(Asset::id));
    }

    Ok((asset_ids, ref_blocks))
}

/// Validates that the number of cycles specified is within the allowed range.
fn validate_num_cycles(num_cycles: u32) -> Result<(), TransactionExecutorError> {
    if !(MIN_TX_EXECUTION_CYCLES..=MAX_TX_EXECUTION_CYCLES).contains(&num_cycles) {
        Err(TransactionExecutorError::InvalidExecutionOptionsCycles {
            min_cycles: MIN_TX_EXECUTION_CYCLES,
            max_cycles: MAX_TX_EXECUTION_CYCLES,
            actual: num_cycles,
        })
    } else {
        Ok(())
    }
}

/// Remaps an execution error to a transaction executor error.
///
/// - If the inner error is [`TransactionKernelError::Unauthorized`], it is remapped to
///   [`TransactionExecutorError::Unauthorized`].
/// - If the inner error is [`TransactionKernelError::AuthRequestOutsideAuthProcedure`], it is
///   remapped to [`TransactionExecutorError::AuthRequestOutsideAuthProcedure`].
/// - If the inner error is
///   [`TransactionKernelError::PrivilegedEventFromOutsideTransactionKernelContext`], it is remapped
///   to [`TransactionExecutorError::PrivilegedEventFromOutsideTransactionKernelContext`].
/// - Otherwise, the execution error is wrapped in
///   [`TransactionExecutorError::TransactionProgramExecutionFailed`].
fn map_execution_error(exec_err: ExecutionError) -> TransactionExecutorError {
    match exec_err {
        ExecutionError::EventError { ref error, .. } => {
            match error.downcast_ref::<TransactionKernelError>() {
                Some(TransactionKernelError::Unauthorized(summary)) => {
                    TransactionExecutorError::Unauthorized(summary.clone())
                },
                Some(TransactionKernelError::MissingAuthenticator) => {
                    TransactionExecutorError::MissingAuthenticator
                },
                Some(TransactionKernelError::AuthRequestOutsideAuthProcedure) => {
                    TransactionExecutorError::AuthRequestOutsideAuthProcedure
                },
                Some(
                    TransactionKernelError::PrivilegedEventFromOutsideTransactionKernelContext(
                        event_id,
                    ),
                ) => TransactionExecutorError::PrivilegedEventFromOutsideTransactionKernelContext(
                    event_id.clone(),
                ),
                _ => TransactionExecutorError::TransactionProgramExecutionFailed(exec_err),
            }
        },
        _ => TransactionExecutorError::TransactionProgramExecutionFailed(exec_err),
    }
}