feat: Add TxDeposit type (#40)

crates/derive/src/types/eips/deposit.rs

@@ -0,0 +1,286 @@
+use crate::types::{
+    network::{Signed, Transaction, TxKind},
+    transaction::TxType,
+};
+use alloc::vec::Vec;
+use alloy_primitives::{keccak256, Address, Bytes, ChainId, Signature, B256, U256};
+use alloy_rlp::{
+    length_of_length, Buf, BufMut, Decodable, Encodable, Error as DecodeError, Header,
+    EMPTY_STRING_CODE,
+};
+use core::mem;
+
+/// Deposit transactions, also known as deposits are initiated on L1, and executed on L2.
+#[derive(Debug, Clone, PartialEq, Eq, Hash, Default)]
+pub struct TxDeposit {
+    /// Hash that uniquely identifies the source of the deposit.
+    pub source_hash: B256,
+    /// The address of the sender account.
+    pub from: Address,
+    /// The address of the recipient account, or the null (zero-length) address if the deposited
+    /// transaction is a contract creation.
+    pub to: TxKind,
+    /// The ETH value to mint on L2.
+    pub mint: Option<u128>,
+    ///  The ETH value to send to the recipient account.
+    pub value: U256,
+    /// The gas limit for the L2 transaction.
+    pub gas_limit: u64,
+    /// Field indicating if this transaction is exempt from the L2 gas limit.
+    pub is_system_transaction: bool,
+    /// Input has two uses depending if transaction is Create or Call (if `to` field is None or
+    /// Some).
+    pub input: Bytes,
+}
+
+impl TxDeposit {
+    /// Calculates a heuristic for the in-memory size of the [TxDeposit] transaction.
+    #[inline]
+    pub fn size(&self) -> usize {
+        mem::size_of::<B256>() + // source_hash
+        mem::size_of::<Address>() + // from
+        self.to.size() + // to
+        mem::size_of::<Option<u128>>() + // mint
+        mem::size_of::<U256>() + // value
+        mem::size_of::<u64>() + // gas_limit
+        mem::size_of::<bool>() + // is_system_transaction
+        self.input.len() // input
+    }
+
+    /// Decodes the inner [TxDeposit] fields from RLP bytes.
+    ///
+    /// NOTE: This assumes a RLP header has already been decoded, and _just_ decodes the following
+    /// RLP fields in the following order:
+    ///
+    /// - `source_hash`
+    /// - `from`
+    /// - `to`
+    /// - `mint`
+    /// - `value`
+    /// - `gas_limit`
+    /// - `is_system_transaction`
+    /// - `input`
+    pub fn decode_inner(buf: &mut &[u8]) -> Result<Self, DecodeError> {
+        Ok(Self {
+            source_hash: Decodable::decode(buf)?,
+            from: Decodable::decode(buf)?,
+            to: Decodable::decode(buf)?,
+            mint: if *buf.first().ok_or(DecodeError::InputTooShort)? == EMPTY_STRING_CODE {
+                buf.advance(1);
+                None
+            } else {
+                Some(Decodable::decode(buf)?)
+            },
+            value: Decodable::decode(buf)?,
+            gas_limit: Decodable::decode(buf)?,
+            is_system_transaction: Decodable::decode(buf)?,
+            input: Decodable::decode(buf)?,
+        })
+    }
+
+    /// Outputs the length of the transaction's fields, without a RLP header or length of the
+    /// eip155 fields.
+    pub(crate) fn fields_len(&self) -> usize {
+        self.source_hash.length()
+            + self.from.length()
+            + self.to.length()
+            + self.mint.map_or(1, |mint| mint.length())
+            + self.value.length()
+            + self.gas_limit.length()
+            + self.is_system_transaction.length()
+            + self.input.0.length()
+    }
+
+    /// Encodes only the transaction's fields into the desired buffer, without a RLP header.
+    /// <https://github.com/ethereum-optimism/optimism/blob/develop/specs/deposits.md#the-deposited-transaction-type>
+    pub(crate) fn encode_fields(&self, out: &mut dyn alloy_rlp::BufMut) {
+        self.source_hash.encode(out);
+        self.from.encode(out);
+        self.to.encode(out);
+        if let Some(mint) = self.mint {
+            mint.encode(out);
+        } else {
+            out.put_u8(EMPTY_STRING_CODE);
+        }
+        self.value.encode(out);
+        self.gas_limit.encode(out);
+        self.is_system_transaction.encode(out);
+        self.input.encode(out);
+    }
+
+    /// Inner encoding function that is used for both rlp [`Encodable`] trait and for calculating
+    /// hash that for eip2718 does not require rlp header.
+    ///
+    /// NOTE: Deposit transactions are not signed, so this function does not encode a signature,
+    /// just the header and transaction rlp.
+    pub(crate) fn encode_with_signature(
+        &self,
+        signature: &Signature,
+        out: &mut dyn alloy_rlp::BufMut,
+    ) {
+        let payload_length = self.fields_len();
+        let header = Header {
+            list: true,
+            payload_length,
+        };
+        header.encode(out);
+        self.encode_fields(out);
+    }
+
+    /// Output the length of the RLP signed transaction encoding. This encodes with a RLP header.
+    pub(crate) fn payload_len(&self) -> usize {
+        let payload_length = self.fields_len();
+        // 'tx type' + 'header length' + 'payload length'
+        let len = 1 + length_of_length(payload_length) + payload_length;
+        length_of_length(len) + len
+    }
+
+    pub(crate) fn payload_len_without_header(&self) -> usize {
+        let payload_length = self.fields_len();
+        // 'transaction type byte length' + 'header length' + 'payload length'
+        1 + length_of_length(payload_length) + payload_length
+    }
+
+    /// Get the transaction type
+    pub(crate) fn tx_type(&self) -> TxType {
+        TxType::Deposit
+    }
+}
+
+impl Encodable for TxDeposit {
+    fn encode(&self, out: &mut dyn alloy_rlp::BufMut) {
+        Header {
+            list: true,
+            payload_length: self.fields_len(),
+        }
+        .encode(out);
+        self.encode_fields(out);
+    }
+
+    fn length(&self) -> usize {
+        let payload_length = self.fields_len();
+        length_of_length(payload_length) + payload_length
+    }
+}
+
+impl Decodable for TxDeposit {
+    fn decode(data: &mut &[u8]) -> alloy_rlp::Result<Self> {
+        let header = Header::decode(data)?;
+        let remaining_len = data.len();
+
+        if header.payload_length > remaining_len {
+            return Err(alloy_rlp::Error::InputTooShort);
+        }
+
+        Self::decode_inner(data)
+    }
+}
+
+impl Transaction for TxDeposit {
+    type Signature = Signature;
+
+    fn encode_for_signing(&self, out: &mut dyn alloy_rlp::BufMut) {
+        out.put_u8(self.tx_type() as u8);
+        Header {
+            list: true,
+            payload_length: self.fields_len(),
+        }
+        .encode(out);
+        self.encode_fields(out);
+    }
+
+    fn payload_len_for_signature(&self) -> usize {
+        let payload_length = self.fields_len();
+        // 'transaction type byte length' + 'header length' + 'payload length'
+        1 + length_of_length(payload_length) + payload_length
+    }
+
+    fn into_signed(self, signature: Signature) -> Signed<Self> {
+        let payload_length = 1 + self.fields_len() + signature.rlp_vrs_len();
+        let mut buf = Vec::with_capacity(payload_length);
+        buf.put_u8(TxType::Eip1559 as u8);
+        self.encode_signed(&signature, &mut buf);
+        let hash = keccak256(&buf);
+
+        // Drop any v chain id value to ensure the signature format is correct at the time of
+        // combination for an EIP-1559 transaction. V should indicate the y-parity of the
+        // signature.
+        Signed::new_unchecked(self, signature.with_parity_bool(), hash)
+    }
+
+    fn encode_signed(&self, signature: &Signature, out: &mut dyn alloy_rlp::BufMut) {
+        TxDeposit::encode_with_signature(self, signature, out)
+    }
+
+    fn decode_signed(buf: &mut &[u8]) -> alloy_rlp::Result<Signed<Self>> {
+        let header = Header::decode(buf)?;
+        if !header.list {
+            return Err(alloy_rlp::Error::UnexpectedString);
+        }
+
+        let tx = Self::decode_inner(buf)?;
+        let signature = Signature::decode_rlp_vrs(buf)?;
+
+        Ok(tx.into_signed(signature))
+    }
+
+    fn input(&self) -> &[u8] {
+        &self.input
+    }
+
+    fn input_mut(&mut self) -> &mut Bytes {
+        &mut self.input
+    }
+
+    fn set_input(&mut self, input: Bytes) {
+        self.input = input;
+    }
+
+    fn to(&self) -> TxKind {
+        self.to
+    }
+
+    fn set_to(&mut self, to: TxKind) {
+        self.to = to;
+    }
+
+    fn value(&self) -> U256 {
+        self.value
+    }
+
+    fn set_value(&mut self, value: U256) {
+        self.value = value;
+    }
+
+    fn chain_id(&self) -> Option<ChainId> {
+        None
+    }
+
+    fn set_chain_id(&mut self, chain_id: ChainId) {
+        unreachable!("Deposit transactions do not have a chain id");
+    }
+
+    fn nonce(&self) -> u64 {
+        0
+    }
+
+    fn set_nonce(&mut self, nonce: u64) {
+        unreachable!("Deposit transactions do not have a nonce");
+    }
+
+    fn gas_limit(&self) -> u64 {
+        self.gas_limit
+    }
+
+    fn set_gas_limit(&mut self, limit: u64) {
+        self.gas_limit = limit;
+    }
+
+    fn gas_price(&self) -> Option<U256> {
+        None
+    }
+
+    fn set_gas_price(&mut self, price: U256) {
+        let _ = price;
+    }
+}

crates/derive/src/types/eips/mod.rs

@@ -12,4 +12,6 @@ pub mod eip4788;
 pub mod eip4844;
 pub use eip4844::{calc_blob_gasprice, calc_excess_blob_gas};
 
+pub mod deposit;
+
 pub mod merge;

crates/derive/src/types/transaction/envelope.rs

@@ -1,5 +1,8 @@
 use crate::types::{
-    eips::eip2718::{Decodable2718, Eip2718Error, Encodable2718},
+    eips::{
+        deposit::TxDeposit,
+        eip2718::{Decodable2718, Eip2718Error, Encodable2718},
+    },
     network::Signed,
     transaction::{TxEip1559, TxEip2930, TxEip4844, TxLegacy},
 };
@@ -23,6 +26,8 @@ pub enum TxType {
     Eip1559 = 2,
     /// EIP-4844 transaction type.
     Eip4844 = 3,
+    /// Optimism Deposit transaction type.
+    Deposit = 126,
 }
 
 impl TryFrom<u8> for TxType {
@@ -31,7 +36,7 @@ impl TryFrom<u8> for TxType {
     fn try_from(value: u8) -> Result<Self, Self::Error> {
         match value {
             // SAFETY: repr(u8) with explicit discriminant
-            ..=3 => Ok(unsafe { core::mem::transmute(value) }),
+            ..=3 | 126 => Ok(unsafe { core::mem::transmute(value) }),
             _ => Err(Eip2718Error::UnexpectedType(value)),
         }
     }
@@ -60,6 +65,8 @@ pub enum TxEnvelope {
     Eip1559(Signed<TxEip1559>),
     /// A [`TxEip4844`].
     Eip4844(Signed<TxEip4844>),
+    /// A [`TxDeposit`].
+    Deposit(Signed<TxDeposit>),
 }
 
 impl From<Signed<TxEip2930>> for TxEnvelope {
@@ -82,6 +89,7 @@ impl TxEnvelope {
             Self::Eip2930(_) => TxType::Eip2930,
             Self::Eip1559(_) => TxType::Eip1559,
             Self::Eip4844(_) => TxType::Eip4844,
+            Self::Deposit(_) => TxType::Deposit,
         }
     }
 
@@ -92,6 +100,7 @@ impl TxEnvelope {
             Self::Eip2930(t) => t.length(),
             Self::Eip1559(t) => t.length(),
             Self::Eip4844(t) => t.length(),
+            Self::Deposit(t) => t.length(),
         }
     }
 
@@ -146,6 +155,9 @@ impl Decodable2718 for TxEnvelope {
             TxType::Eip4844 => Ok(Self::Eip4844(
                 Decodable::decode(buf).map_err(Eip2718Error::RlpError)?,
             )),
+            TxType::Deposit => Ok(Self::Deposit(
+                Decodable::decode(buf).map_err(Eip2718Error::RlpError)?,
+            )),
         }
     }
 
@@ -164,6 +176,7 @@ impl Encodable2718 for TxEnvelope {
             Self::Eip2930(_) => Some(TxType::Eip2930 as u8),
             Self::Eip1559(_) => Some(TxType::Eip1559 as u8),
             Self::Eip4844(_) => Some(TxType::Eip4844 as u8),
+            Self::Deposit(_) => Some(TxType::Deposit as u8),
         }
     }
 
@@ -190,6 +203,10 @@ impl Encodable2718 for TxEnvelope {
                 out.put_u8(TxType::Eip4844 as u8);
                 tx.encode(out);
             }
+            TxEnvelope::Deposit(tx) => {
+                out.put_u8(TxType::Deposit as u8);
+                tx.encode(out);
+            }
         }
     }
 }