fuel-vm 0.66.3

FuelVM interpreter.
Documentation 
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//! Stategies for verifying the correctness of the VM execution.
//! The default strategy, [`Normal`], simply returns an error on failed verification.
//! Alternative strategy, [`AttemptContinue`], continues execution and collects multiple
//! errors.

use alloc::{
    collections::BTreeSet,
    vec::Vec,
};

use fuel_tx::{
    ContractId,
    PanicReason,
};

use crate::{
    error::PanicOrBug,
    interpreter::PanicContext,
};

/// Do not allow outside implementations for the Verifier, so that it's not a breaking
/// change to modify it.
trait Seal {}

/// What to do when verification fails.
#[allow(private_bounds)] // For selaed trait
pub trait Verifier
where
    Self: Sized + Seal,
{
    /// Handle an error after a contract is missing from the inputs
    #[allow(private_interfaces)] // PanicContext is an internal type, so this isn't callable by external code
    fn check_contract_in_inputs(
        &mut self,
        panic_context: &mut PanicContext,
        input_contracts: &BTreeSet<ContractId>,
        contract_id: &ContractId,
    ) -> Result<(), PanicOrBug>;
}

/// The default verification strategy.
/// Performs the standard verification checks and panics on failure.
#[derive(Debug, Copy, Clone, Default, PartialEq, Eq)]
pub struct Normal;

impl Verifier for Normal
where
    Self: Sized,
{
    #[allow(private_interfaces)]
    fn check_contract_in_inputs(
        &mut self,
        panic_context: &mut PanicContext,
        input_contracts: &BTreeSet<ContractId>,
        contract_id: &ContractId,
    ) -> Result<(), PanicOrBug> {
        if input_contracts.contains(contract_id) {
            Ok(())
        } else {
            *panic_context = PanicContext::ContractId(*contract_id);
            Err(PanicReason::ContractNotInInputs.into())
        }
    }
}

impl Seal for Normal {}

/// With some subset of errors it's possible to continue execution,
/// allowing the collection of multiple errors during a single run.
#[derive(Debug, Clone, Default)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
#[non_exhaustive]
pub struct AttemptContinue {
    /// Contracts that were called but not in the inputs
    pub missing_contract_inputs: Vec<ContractId>,
}

impl Verifier for AttemptContinue
where
    Self: Sized,
{
    #[allow(private_interfaces)]
    fn check_contract_in_inputs(
        &mut self,
        _panic_context: &mut PanicContext,
        input_contracts: &BTreeSet<ContractId>,
        contract_id: &ContractId,
    ) -> Result<(), PanicOrBug> {
        if !input_contracts.contains(contract_id) {
            self.missing_contract_inputs.push(*contract_id);
        }
        Ok(())
    }
}

impl Seal for AttemptContinue {}