miden_objects/account/component/

mod.rs

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

use assembly::{Assembler, Compile, Library};
use vm_processor::MastForest;

mod template;
pub use template::*;

use crate::{
    AccountError,
    account::{AccountType, StorageSlot},
};

/// An [`AccountComponent`] defines a [`Library`] of code and the initial value and types of
/// the [`StorageSlot`]s it accesses.
///
/// One or more components can be used to built [`AccountCode`](crate::account::AccountCode) and
/// [`AccountStorage`](crate::account::AccountStorage).
///
/// Each component is independent of other components and can only access its own storage slots.
/// Each component defines its own storage layout starting at index 0 up to the length of the
/// storage slots vector.
///
/// Components define the [`AccountType`]s they support, meaning whether the component can be used
/// to instantiate an account of that type. For example, a component implementing a fungible faucet
/// would only specify support for [`AccountType::FungibleFaucet`]. Using it to instantiate a
/// regular account would fail. By default, the set of supported types is empty, so each component
/// is forced to explicitly define what it supports.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct AccountComponent {
    pub(super) library: Library,
    pub(super) storage_slots: Vec<StorageSlot>,
    pub(super) supported_types: BTreeSet<AccountType>,
}

impl AccountComponent {
    // CONSTRUCTORS
    // --------------------------------------------------------------------------------------------

    /// Returns a new [`AccountComponent`] constructed from the provided `library` and
    /// `storage_slots`.
    ///
    /// All procedures exported from the provided code will become members of the account's public
    /// interface when added to an [`AccountCode`](crate::account::AccountCode).
    ///
    /// # Errors
    ///
    /// The following list of errors is exhaustive and can be relied upon for `expect`ing the call
    /// to this function. It is recommended that custom components ensure these conditions by design
    /// or in their fallible constructors.
    ///
    /// Returns an error if:
    /// - The number of given [`StorageSlot`]s exceeds 255.
    pub fn new(code: Library, storage_slots: Vec<StorageSlot>) -> Result<Self, AccountError> {
        // Check that we have less than 256 storage slots.
        u8::try_from(storage_slots.len())
            .map_err(|_| AccountError::StorageTooManySlots(storage_slots.len() as u64))?;

        Ok(Self {
            library: code,
            storage_slots,
            supported_types: BTreeSet::new(),
        })
    }

    /// Returns a new [`AccountComponent`] whose library is compiled from the provided `source_code`
    /// using the specified `assembler` and with the given `storage_slots`.
    ///
    /// All procedures exported from the provided code will become members of the account's public
    /// interface when added to an [`AccountCode`](crate::account::AccountCode).
    ///
    /// # Errors
    ///
    /// Returns an error if:
    /// - the compilation of the provided source code fails.
    /// - The number of storage slots exceeds 255.
    pub fn compile(
        source_code: impl Compile,
        assembler: Assembler,
        storage_slots: Vec<StorageSlot>,
    ) -> Result<Self, AccountError> {
        let library = assembler
            .assemble_library([source_code])
            .map_err(AccountError::AccountComponentAssemblyError)?;

        Self::new(library, storage_slots)
    }

    /// Instantiates an [AccountComponent] from the [AccountComponentTemplate].
    ///
    /// The template's component metadata might contain placeholders, which can be replaced by
    /// mapping storage placeholders to values through the `init_storage_data` parameter.
    ///
    /// # Errors
    ///
    /// - If any of the component's storage entries cannot be transformed into a valid storage slot.
    ///   This could be because the metadata is invalid, or storage values were not provided (or
    ///   they are not of a valid type)
    pub fn from_template(
        template: &AccountComponentTemplate,
        init_storage_data: &InitStorageData,
    ) -> Result<AccountComponent, AccountError> {
        let mut storage_slots = vec![];
        for storage_entry in template.metadata().storage_entries() {
            let entry_storage_slots = storage_entry
                .try_build_storage_slots(init_storage_data)
                .map_err(AccountError::AccountComponentTemplateInstantiationError)?;
            storage_slots.extend(entry_storage_slots);
        }

        Ok(AccountComponent::new(template.library().clone(), storage_slots)?
            .with_supported_types(template.metadata().supported_types().clone()))
    }

    // ACCESSORS
    // --------------------------------------------------------------------------------------------

    /// Returns the number of storage slots accessible from this component.
    pub fn storage_size(&self) -> u8 {
        u8::try_from(self.storage_slots.len())
            .expect("storage slots len should fit in u8 per the constructor")
    }

    /// Returns a reference to the underlying [`Library`] of this component.
    pub fn library(&self) -> &Library {
        &self.library
    }

    /// Returns a reference to the underlying [`MastForest`] of this component.
    pub fn mast_forest(&self) -> &MastForest {
        self.library.mast_forest().as_ref()
    }

    /// Returns a slice of the underlying [`StorageSlot`]s of this component.
    pub fn storage_slots(&self) -> &[StorageSlot] {
        self.storage_slots.as_slice()
    }

    /// Returns a reference to the supported [`AccountType`]s.
    pub fn supported_types(&self) -> &BTreeSet<AccountType> {
        &self.supported_types
    }

    /// Returns `true` if this component supports the given `account_type`, `false` otherwise.
    pub fn supports_type(&self, account_type: AccountType) -> bool {
        self.supported_types.contains(&account_type)
    }

    // MUTATORS
    // --------------------------------------------------------------------------------------------

    /// Adds `supported_type` to the set of [`AccountType`]s supported by this component.
    ///
    /// This function has the semantics of [`BTreeSet::insert`], i.e. adding a type twice is fine
    /// and it can be called multiple times with different account types.
    pub fn with_supported_type(mut self, supported_type: AccountType) -> Self {
        self.supported_types.insert(supported_type);
        self
    }

    /// Overwrites any previously set supported types with the given set.
    ///
    /// This can be used to reset the supported types of a component to a chosen set, which may be
    /// useful after cloning an existing component.
    pub fn with_supported_types(mut self, supported_types: BTreeSet<AccountType>) -> Self {
        self.supported_types = supported_types;
        self
    }

    /// Sets the [`AccountType`]s supported by this component to all account types.
    pub fn with_supports_all_types(mut self) -> Self {
        self.supported_types.extend([
            AccountType::FungibleFaucet,
            AccountType::NonFungibleFaucet,
            AccountType::RegularAccountImmutableCode,
            AccountType::RegularAccountUpdatableCode,
        ]);
        self
    }
}

impl From<AccountComponent> for Library {
    fn from(component: AccountComponent) -> Self {
        component.library
    }
}