feat(rpc-types): RLP encoding/decoding for transaction types (#36)

* feat: add rlp encoding/decoding to tx types

* feat: add encodable/decodable traits to tx

* chore: remove out-of-scope func

* chore: remove bad links on comments

* chore: fix docs

* clippy

crates/rpc-types/src/eth/transaction/access_list.rs

@@ -1,9 +1,13 @@
+use std::mem;
+use alloy_rlp::{RlpDecodable, RlpEncodable};
 use alloy_primitives::{Address, U256, B256};
 use serde::{Deserialize, Serialize};
 
 /// A list of addresses and storage keys that the transaction plans to access.
 /// Accesses outside the list are possible, but become more expensive.
-#[derive(Deserialize, Serialize, Clone, Debug, PartialEq, Eq, Hash, Default)]
+#[derive(
+    Deserialize, Serialize, Clone, Debug, PartialEq, Eq, Hash, Default, RlpEncodable, RlpDecodable,
+)]
 #[serde(rename_all = "camelCase")]
 pub struct AccessListItem {
     /// Account addresses that would be loaded at the start of execution
@@ -12,8 +16,18 @@ pub struct AccessListItem {
     pub storage_keys: Vec<B256>,
 }
 
+impl AccessListItem {
+    /// Calculates a heuristic for the in-memory size of the [AccessListItem].
+    #[inline]
+    pub fn size(&self) -> usize {
+        mem::size_of::<Address>() + self.storage_keys.capacity() * mem::size_of::<U256>()
+    }
+}
+
 /// AccessList as defined in EIP-2930
-#[derive(Deserialize, Serialize, Clone, Debug, PartialEq, Eq, Hash, Default)]
+#[derive(
+    Deserialize, Serialize, Clone, Debug, PartialEq, Eq, Hash, Default, RlpEncodable, RlpDecodable,
+)]
 pub struct AccessList(pub Vec<AccessListItem>);
 
 impl AccessList {
@@ -52,6 +66,14 @@ impl AccessList {
             )
         })
     }
+
+    /// Calculates a heuristic for the in-memory size of the [AccessList].
+    #[inline]
+    pub fn size(&self) -> usize {
+        // take into account capacity
+        self.0.iter().map(AccessListItem::size).sum::<usize>()
+            + self.0.capacity() * mem::size_of::<AccessListItem>()
+    }
 }
 
 /// Access list with gas used appended.

crates/rpc-types/src/eth/transaction/mod.rs

@@ -12,8 +12,11 @@ mod common;
 mod receipt;
 mod request;
 mod signature;
+mod tx_type;
 mod typed;
 
+pub use tx_type::*;
+
 /// Transaction object used in RPC
 #[derive(Debug, Default, Clone, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
@@ -66,9 +69,6 @@ pub struct Transaction {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub access_list: Option<Vec<AccessListItem>>,
     /// EIP2718
-    ///
-    /// Transaction type, Some(2) for EIP-1559 transaction,
-    /// Some(1) for AccessList transaction, None for Legacy
     #[serde(rename = "type", skip_serializing_if = "Option::is_none")]
     pub transaction_type: Option<U64>,
 }

crates/rpc-types/src/eth/transaction/signature.rs

@@ -1,5 +1,6 @@
 //! Signature related RPC values
 use alloy_primitives::U256;
+use alloy_rlp::{Bytes, Decodable, Encodable, Error as RlpError};
 use serde::{Deserialize, Serialize};
 
 /// Container type for all signature fields in RPC
@@ -23,10 +24,119 @@ pub struct Signature {
     pub y_parity: Option<Parity>,
 }
 
+impl Signature {
+    /// Output the length of the signature without the length of the RLP header, using the legacy
+    /// scheme with EIP-155 support depends on chain_id.
+    pub fn payload_len_with_eip155_chain_id(&self, chain_id: Option<u64>) -> usize {
+        self.v(chain_id).length() + self.r.length() + self.s.length()
+    }
+
+    /// Encode the `v`, `r`, `s` values without a RLP header.
+    /// Encodes the `v` value using the legacy scheme with EIP-155 support depends on chain_id.
+    pub fn encode_with_eip155_chain_id(
+        &self,
+        out: &mut dyn alloy_rlp::BufMut,
+        chain_id: Option<u64>,
+    ) {
+        self.v(chain_id).encode(out);
+        self.r.encode(out);
+        self.s.encode(out);
+    }
+
+    /// Output the `v` of the signature depends on chain_id
+    #[inline]
+    pub fn v(&self, chain_id: Option<u64>) -> u64 {
+        if let Some(chain_id) = chain_id {
+            // EIP-155: v = {0, 1} + CHAIN_ID * 2 + 35
+            let y_parity = u64::from(self.y_parity.unwrap_or(Parity(false)));
+            y_parity + chain_id * 2 + 35
+        } else {
+            u64::from(self.y_parity.unwrap_or(Parity(false))) + 27
+        }
+    }
+
+    /// Decodes the `v`, `r`, `s` values without a RLP header.
+    /// This will return a chain ID if the `v` value is [EIP-155](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-155.md) compatible.
+    pub fn decode_with_eip155_chain_id(buf: &mut &[u8]) -> alloy_rlp::Result<(Self, Option<u64>)> {
+        let v = u64::decode(buf)?;
+        let r = Decodable::decode(buf)?;
+        let s = Decodable::decode(buf)?;
+        if v >= 35 {
+            // EIP-155: v = {0, 1} + CHAIN_ID * 2 + 35
+            let y_parity = ((v - 35) % 2) != 0;
+            let chain_id = (v - 35) >> 1;
+            Ok((
+                Signature { r, s, y_parity: Some(Parity(y_parity)), v: U256::from(v) },
+                Some(chain_id),
+            ))
+        } else {
+            // non-EIP-155 legacy scheme, v = 27 for even y-parity, v = 28 for odd y-parity
+            if v != 27 && v != 28 {
+                return Err(RlpError::Custom("invalid Ethereum signature (V is not 27 or 28)"));
+            }
+            let y_parity = v == 28;
+            Ok((Signature { r, s, y_parity: Some(Parity(y_parity)), v: U256::from(v) }, None))
+        }
+    }
+
+    /// Output the length of the signature without the length of the RLP header
+    pub fn payload_len(&self) -> usize {
+        let y_parity_len = match self.y_parity {
+            Some(parity) => parity.0 as usize,
+            None => 0_usize,
+        };
+        y_parity_len + self.r.length() + self.s.length()
+    }
+
+    /// Encode the `y_parity`, `r`, `s` values without a RLP header.
+    /// Panics if the y parity is not set.
+    pub fn encode(&self, out: &mut dyn alloy_rlp::BufMut) {
+        self.y_parity.expect("y_parity not set").encode(out);
+        self.r.encode(out);
+        self.s.encode(out);
+    }
+
+    /// Decodes the `y_parity`, `r`, `s` values without a RLP header.
+    pub fn decode(buf: &mut &[u8]) -> alloy_rlp::Result<Self> {
+        let mut sig =
+            Signature {
+                y_parity: Some(Decodable::decode(buf)?),
+                r: Decodable::decode(buf)?,
+                s: Decodable::decode(buf)?,
+                v: U256::ZERO,
+            };
+        sig.v = sig.y_parity.unwrap().into();
+        Ok(sig)
+    }
+
+    /// Turn this signature into its byte
+    /// (hex) representation.
+    /// Panics: if the y_parity field is not set.
+    pub fn to_bytes(&self) -> [u8; 65] {
+        let mut sig = [0u8; 65];
+        sig[..32].copy_from_slice(&self.r.to_be_bytes::<32>());
+        sig[32..64].copy_from_slice(&self.s.to_be_bytes::<32>());
+        let v = u8::from(self.y_parity.expect("y_parity not set")) + 27;
+        sig[64] = v;
+        sig
+    }
+
+    /// Turn this signature into its hex-encoded representation.
+    pub fn to_hex_bytes(&self) -> Bytes {
+        alloy_primitives::hex::encode(self.to_bytes()).into()
+    }
+
+    /// Calculates a heuristic for the in-memory size of the [Signature].
+    #[inline]
+    pub fn size(&self) -> usize {
+        std::mem::size_of::<Self>()
+    }
+}
+
 /// Type that represents the signature parity byte, meant for use in RPC.
 ///
 /// This will be serialized as "0x0" if false, and "0x1" if true.
-#[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
+#[derive(Copy, Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
 pub struct Parity(
     #[serde(serialize_with = "serialize_parity", deserialize_with = "deserialize_parity")] pub bool,
 );
@@ -37,6 +147,62 @@ impl From<bool> for Parity {
     }
 }
 
+impl From<U256> for Parity {
+    fn from(value: U256) -> Self {
+        match value {
+            U256::ZERO => Self(false),
+            _ => Self(true),
+        }
+    }
+}
+
+impl From<Parity> for U256 {
+    fn from(p: Parity) -> Self {
+        if p.0 {
+            U256::from(1)
+        } else {
+            U256::ZERO
+        }
+    }
+}
+
+impl From<Parity> for u64 {
+    fn from(p: Parity) -> Self {
+        if p.0 {
+            1
+        } else {
+            0
+        }
+    }
+}
+
+impl From<Parity> for u8 {
+    fn from(value: Parity) -> Self {
+        match value.0 {
+            true => 1,
+            false => 0,
+        }
+    }
+}
+
+impl Encodable for Parity {
+    fn encode(&self, out: &mut dyn alloy_rlp::BufMut) {
+        let v = u8::from(*self);
+        v.encode(out);
+    }
+
+    fn length(&self) -> usize {
+        1
+    }
+}
+
+impl Decodable for Parity {
+    fn decode(buf: &mut &[u8]) -> alloy_rlp::Result<Self> {
+        let v = u8::decode(buf)?;
+        Ok(Self(v != 0))
+    }
+}
+
 fn serialize_parity<S>(parity: &bool, serializer: S) -> Result<S::Ok, S::Error>
 where
     S: serde::Serializer,

crates/rpc-types/src/eth/transaction/tx_type.rs

@@ -0,0 +1,52 @@
+use alloy_primitives::U8;
+use serde::{Deserialize, Serialize};
+
+/// Identifier for legacy transaction, however a legacy tx is technically not
+/// typed.
+pub const LEGACY_TX_TYPE_ID: u8 = 0;
+
+/// Identifier for an EIP2930 transaction.
+pub const EIP2930_TX_TYPE_ID: u8 = 1;
+
+/// Identifier for an EIP1559 transaction.
+pub const EIP1559_TX_TYPE_ID: u8 = 2;
+
+/// Identifier for an EIP4844 transaction.
+pub const EIP4844_TX_TYPE_ID: u8 = 3;
+
+/// Transaction Type
+///
+/// Currently being used as 2-bit type when encoding it to Compact on
+/// crate::TransactionSignedNoHash (see Reth's Compact encoding). Adding more transaction types will break the codec and
+/// database format on Reth.
+///
+/// Other required changes when adding a new type can be seen on [PR#3953](https://github.com/paradigmxyz/reth/pull/3953/files).
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Default, Serialize, Deserialize)]
+pub enum TxType {
+    /// Legacy transaction pre EIP-2929
+    #[default]
+    Legacy = 0_isize,
+    /// AccessList transaction
+    EIP2930 = 1_isize,
+    /// Transaction with Priority fee
+    EIP1559 = 2_isize,
+    /// Shard Blob Transactions - EIP-4844
+    EIP4844 = 3_isize,
+}
+
+impl From<TxType> for u8 {
+    fn from(value: TxType) -> Self {
+        match value {
+            TxType::Legacy => LEGACY_TX_TYPE_ID,
+            TxType::EIP2930 => EIP2930_TX_TYPE_ID,
+            TxType::EIP1559 => EIP1559_TX_TYPE_ID,
+            TxType::EIP4844 => EIP4844_TX_TYPE_ID,
+        }
+    }
+}
+
+impl From<TxType> for U8 {
+    fn from(value: TxType) -> Self {
+        U8::from(u8::from(value))
+    }
+}