nanoreth/crates/payload/primitives/src/traits.rs

use crate::{PayloadBuilderError, PayloadEvents, PayloadTypes};
use alloy_primitives::{Address, B256, U256};
use alloy_rpc_types::{
    engine::{PayloadAttributes as EthPayloadAttributes, PayloadId},
    Withdrawal,
};
use op_alloy_rpc_types_engine::OpPayloadAttributes;
use reth_chain_state::ExecutedBlock;
use reth_primitives::{SealedBlock, Withdrawals};
use std::{future::Future, pin::Pin};
use tokio::sync::oneshot;

pub(crate) type PayloadFuture<P> =
    Pin<Box<dyn Future<Output = Result<P, PayloadBuilderError>> + Send + Sync>>;

/// A type that can request, subscribe to and resolve payloads.
#[async_trait::async_trait]
pub trait PayloadBuilder: Send + Unpin {
    /// The Payload type for the builder.
    type PayloadType: PayloadTypes;
    /// The error type returned by the builder.
    type Error;

    /// Sends a message to the service to start building a new payload for the given payload
    /// attributes and returns a future that resolves to the payload.
    async fn send_and_resolve_payload(
        &self,
        attr: <Self::PayloadType as PayloadTypes>::PayloadBuilderAttributes,
    ) -> Result<PayloadFuture<<Self::PayloadType as PayloadTypes>::BuiltPayload>, Self::Error>;

    /// Returns the best payload for the given identifier.
    async fn best_payload(
        &self,
        id: PayloadId,
    ) -> Option<Result<<Self::PayloadType as PayloadTypes>::BuiltPayload, Self::Error>>;

    /// Sends a message to the service to start building a new payload for the given payload.
    ///
    /// This is the same as [`PayloadBuilder::new_payload`] but does not wait for the result
    /// and returns the receiver instead
    fn send_new_payload(
        &self,
        attr: <Self::PayloadType as PayloadTypes>::PayloadBuilderAttributes,
    ) -> oneshot::Receiver<Result<PayloadId, Self::Error>>;

    /// Starts building a new payload for the given payload attributes.
    ///
    /// Returns the identifier of the payload.
    async fn new_payload(
        &self,
        attr: <Self::PayloadType as PayloadTypes>::PayloadBuilderAttributes,
    ) -> Result<PayloadId, Self::Error>;

    /// Sends a message to the service to subscribe to payload events.
    /// Returns a receiver that will receive them.
    async fn subscribe(&self) -> Result<PayloadEvents<Self::PayloadType>, Self::Error>;
}

/// Represents a built payload type that contains a built [`SealedBlock`] and can be converted into
/// engine API execution payloads.
pub trait BuiltPayload: Send + Sync + std::fmt::Debug {
    /// Returns the built block (sealed)
    fn block(&self) -> &SealedBlock;

    /// Returns the fees collected for the built block
    fn fees(&self) -> U256;

    /// Returns the entire execution data for the built block, if available.
    fn executed_block(&self) -> Option<ExecutedBlock> {
        None
    }
}

/// This can be implemented by types that describe a currently running payload job.
///
/// This is used as a conversion type, transforming a payload attributes type that the engine API
/// receives, into a type that the payload builder can use.
pub trait PayloadBuilderAttributes: Send + Sync + std::fmt::Debug {
    /// The payload attributes that can be used to construct this type. Used as the argument in
    /// [`PayloadBuilderAttributes::try_new`].
    type RpcPayloadAttributes;
    /// The error type used in [`PayloadBuilderAttributes::try_new`].
    type Error: core::error::Error;

    /// Creates a new payload builder for the given parent block and the attributes.
    ///
    /// Derives the unique [`PayloadId`] for the given parent and attributes
    fn try_new(
        parent: B256,
        rpc_payload_attributes: Self::RpcPayloadAttributes,
    ) -> Result<Self, Self::Error>
    where
        Self: Sized;

    /// Returns the [`PayloadId`] for the running payload job.
    fn payload_id(&self) -> PayloadId;

    /// Returns the parent block hash for the running payload job.
    fn parent(&self) -> B256;

    /// Returns the timestamp for the running payload job.
    fn timestamp(&self) -> u64;

    /// Returns the parent beacon block root for the running payload job, if it exists.
    fn parent_beacon_block_root(&self) -> Option<B256>;

    /// Returns the suggested fee recipient for the running payload job.
    fn suggested_fee_recipient(&self) -> Address;

    /// Returns the prevrandao field for the running payload job.
    fn prev_randao(&self) -> B256;

    /// Returns the withdrawals for the running payload job.
    fn withdrawals(&self) -> &Withdrawals;
}

/// The execution payload attribute type the CL node emits via the engine API.
/// This trait should be implemented by types that could be used to spawn a payload job.
///
/// This type is emitted as part of the forkchoiceUpdated call
pub trait PayloadAttributes:
    serde::de::DeserializeOwned + serde::Serialize + std::fmt::Debug + Clone + Send + Sync + 'static
{
    /// Returns the timestamp to be used in the payload job.
    fn timestamp(&self) -> u64;

    /// Returns the withdrawals for the given payload attributes.
    fn withdrawals(&self) -> Option<&Vec<Withdrawal>>;

    /// Return the parent beacon block root for the payload attributes.
    fn parent_beacon_block_root(&self) -> Option<B256>;
}

impl PayloadAttributes for EthPayloadAttributes {
    fn timestamp(&self) -> u64 {
        self.timestamp
    }

    fn withdrawals(&self) -> Option<&Vec<Withdrawal>> {
        self.withdrawals.as_ref()
    }

    fn parent_beacon_block_root(&self) -> Option<B256> {
        self.parent_beacon_block_root
    }
}

impl PayloadAttributes for OpPayloadAttributes {
    fn timestamp(&self) -> u64 {
        self.payload_attributes.timestamp
    }

    fn withdrawals(&self) -> Option<&Vec<Withdrawal>> {
        self.payload_attributes.withdrawals.as_ref()
    }

    fn parent_beacon_block_root(&self) -> Option<B256> {
        self.payload_attributes.parent_beacon_block_root
    }
}

/// A builder that can return the current payload attribute.
pub trait PayloadAttributesBuilder<Attributes>: Send + Sync + 'static {
    /// Return a new payload attribute from the builder.
    fn build(&self, timestamp: u64) -> Attributes;
}