signed.rs

use crate::transaction::{RlpEcdsaDecodableTx, RlpEcdsaEncodableTx, SignableTransaction};
use alloy_eips::eip2718::Eip2718Result;
use alloy_primitives::{Signature, B256};
use alloy_rlp::BufMut;
use core::hash::{Hash, Hasher};
#[cfg(not(feature = "std"))]
use once_cell::race::OnceBox as OnceLock;
#[cfg(feature = "std")]
use std::sync::OnceLock;

/// A transaction with a signature and hash seal.
#[derive(Debug, Clone)]
pub struct Signed<T, Sig = Signature> {
    #[doc(alias = "transaction")]
    tx: T,
    signature: Sig,
    #[doc(alias = "tx_hash", alias = "transaction_hash")]
    hash: OnceLock<B256>,
}

impl<T, Sig> Signed<T, Sig> {
    /// Instantiate from a transaction and signature. Does not verify the signature.
    pub fn new_unchecked(tx: T, signature: Sig, hash: B256) -> Self {
        let value = OnceLock::new();
        #[allow(clippy::useless_conversion)]
        value.get_or_init(|| hash.into());
        Self { tx, signature, hash: value }
    }

    /// Instantiate from a transaction and signature. Does not verify the signature.
    pub const fn new_unhashed(tx: T, signature: Sig) -> Self {
        Self { tx, signature, hash: OnceLock::new() }
    }

    /// Returns a reference to the transaction.
    #[doc(alias = "transaction")]
    pub const fn tx(&self) -> &T {
        &self.tx
    }

    /// Returns a mutable reference to the transaction.
    pub fn tx_mut(&mut self) -> &mut T {
        &mut self.tx
    }

    /// Returns a reference to the signature.
    pub const fn signature(&self) -> &Sig {
        &self.signature
    }

    /// Returns the transaction without signature.
    pub fn strip_signature(self) -> T {
        self.tx
    }

    /// Converts the transaction type to the given alternative that is `From<T>`
    ///
    /// Caution: This is only intended for converting transaction types that are structurally
    /// equivalent (produce the same hash).
    pub fn convert<U>(self) -> Signed<U, Sig>
    where
        U: From<T>,
    {
        self.map(U::from)
    }

    /// Converts the transaction to the given alternative that is `TryFrom<T>`
    ///
    /// Returns the transaction with the new transaction type if all conversions were successful.
    ///
    /// Caution: This is only intended for converting transaction types that are structurally
    /// equivalent (produce the same hash).
    pub fn try_convert<U>(self) -> Result<Signed<U, Sig>, U::Error>
    where
        U: TryFrom<T>,
    {
        self.try_map(U::try_from)
    }

    /// Applies the given closure to the inner transaction type.
    ///
    /// Caution: This is only intended for converting transaction types that are structurally
    /// equivalent (produce the same hash).
    pub fn map<Tx>(self, f: impl FnOnce(T) -> Tx) -> Signed<Tx, Sig> {
        let Self { tx, signature, hash } = self;
        Signed { tx: f(tx), signature, hash }
    }

    /// Applies the given fallible closure to the inner transactions.
    ///
    /// Caution: This is only intended for converting transaction types that are structurally
    /// equivalent (produce the same hash).
    pub fn try_map<Tx, E>(self, f: impl FnOnce(T) -> Result<Tx, E>) -> Result<Signed<Tx, Sig>, E> {
        let Self { tx, signature, hash } = self;
        Ok(Signed { tx: f(tx)?, signature, hash })
    }
}

impl<T: SignableTransaction<Sig>, Sig> Signed<T, Sig> {
    /// Calculate the signing hash for the transaction.
    pub fn signature_hash(&self) -> B256 {
        self.tx.signature_hash()
    }
}

impl<T> Signed<T>
where
    T: RlpEcdsaEncodableTx,
{
    /// Returns a reference to the transaction hash.
    #[doc(alias = "tx_hash", alias = "transaction_hash")]
    pub fn hash(&self) -> &B256 {
        #[allow(clippy::useless_conversion)]
        self.hash.get_or_init(|| self.tx.tx_hash(&self.signature).into())
    }

    /// Splits the transaction into parts.
    pub fn into_parts(self) -> (T, Signature, B256) {
        let hash = *self.hash();
        (self.tx, self.signature, hash)
    }

    /// Get the length of the transaction when RLP encoded.
    pub fn rlp_encoded_length(&self) -> usize {
        self.tx.rlp_encoded_length_with_signature(&self.signature)
    }

    /// RLP encode the signed transaction.
    pub fn rlp_encode(&self, out: &mut dyn BufMut) {
        self.tx.rlp_encode_signed(&self.signature, out);
    }

    /// Get the length of the transaction when EIP-2718 encoded.
    pub fn eip2718_encoded_length(&self) -> usize {
        self.tx.eip2718_encoded_length(&self.signature)
    }

    /// EIP-2718 encode the signed transaction with a specified type flag.
    pub fn eip2718_encode_with_type(&self, ty: u8, out: &mut dyn BufMut) {
        self.tx.eip2718_encode_with_type(&self.signature, ty, out);
    }

    /// EIP-2718 encode the signed transaction.
    pub fn eip2718_encode(&self, out: &mut dyn BufMut) {
        self.tx.eip2718_encode(&self.signature, out);
    }

    /// Get the length of the transaction when network encoded.
    pub fn network_encoded_length(&self) -> usize {
        self.tx.network_encoded_length(&self.signature)
    }

    /// Network encode the signed transaction with a specified type flag.
    pub fn network_encode_with_type(&self, ty: u8, out: &mut dyn BufMut) {
        self.tx.network_encode_with_type(&self.signature, ty, out);
    }

    /// Network encode the signed transaction.
    pub fn network_encode(&self, out: &mut dyn BufMut) {
        self.tx.network_encode(&self.signature, out);
    }
}

impl<T> Signed<T>
where
    T: RlpEcdsaDecodableTx,
{
    /// RLP decode the signed transaction.
    pub fn rlp_decode(buf: &mut &[u8]) -> alloy_rlp::Result<Self> {
        T::rlp_decode_signed(buf)
    }

    /// EIP-2718 decode the signed transaction with a specified type flag.
    pub fn eip2718_decode_with_type(buf: &mut &[u8], ty: u8) -> Eip2718Result<Self> {
        T::eip2718_decode_with_type(buf, ty)
    }

    /// EIP-2718 decode the signed transaction.
    pub fn eip2718_decode(buf: &mut &[u8]) -> Eip2718Result<Self> {
        T::eip2718_decode(buf)
    }

    /// Network decode the signed transaction with a specified type flag.
    pub fn network_decode_with_type(buf: &mut &[u8], ty: u8) -> Eip2718Result<Self> {
        T::network_decode_with_type(buf, ty)
    }

    /// Network decode the signed transaction.
    pub fn network_decode(buf: &mut &[u8]) -> Eip2718Result<Self> {
        T::network_decode(buf)
    }
}

impl<T> Hash for Signed<T>
where
    T: RlpEcdsaDecodableTx + Hash,
{
    fn hash<H: Hasher>(&self, state: &mut H) {
        self.hash().hash(state);
        self.tx.hash(state);
        self.signature.hash(state);
    }
}

impl<T: RlpEcdsaEncodableTx + PartialEq> PartialEq for Signed<T> {
    fn eq(&self, other: &Self) -> bool {
        self.hash() == other.hash() && self.tx == other.tx && self.signature == other.signature
    }
}

impl<T: RlpEcdsaEncodableTx + PartialEq> Eq for Signed<T> {}

#[cfg(feature = "k256")]
impl<T: SignableTransaction<Signature>> Signed<T, Signature> {
    /// Recover the signer of the transaction
    pub fn recover_signer(
        &self,
    ) -> Result<alloy_primitives::Address, alloy_primitives::SignatureError> {
        let sighash = self.tx.signature_hash();
        self.signature.recover_address_from_prehash(&sighash)
    }

    /// Attempts to recover signer and constructs a [`crate::transaction::Recovered`] object.
    pub fn try_into_recovered(
        self,
    ) -> Result<crate::transaction::Recovered<T>, alloy_primitives::SignatureError> {
        let signer = self.recover_signer()?;
        Ok(crate::transaction::Recovered::new_unchecked(self.tx, signer))
    }

    /// Attempts to recover signer and constructs a [`crate::transaction::Recovered`] with a
    /// reference to the transaction `Recovered<&T>`
    pub fn try_to_recovered_ref(
        &self,
    ) -> Result<crate::transaction::Recovered<&T>, alloy_primitives::SignatureError> {
        let signer = self.recover_signer()?;
        Ok(crate::transaction::Recovered::new_unchecked(&self.tx, signer))
    }
}

#[cfg(all(any(test, feature = "arbitrary"), feature = "k256"))]
impl<'a, T: SignableTransaction<Signature> + arbitrary::Arbitrary<'a>> arbitrary::Arbitrary<'a>
    for Signed<T, Signature>
{
    fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {
        use k256::{
            ecdsa::{signature::hazmat::PrehashSigner, SigningKey},
            NonZeroScalar,
        };
        use rand::{rngs::StdRng, SeedableRng};

        let rng_seed = u.arbitrary::<[u8; 32]>()?;
        let mut rand_gen = StdRng::from_seed(rng_seed);
        let signing_key: SigningKey = NonZeroScalar::random(&mut rand_gen).into();

        let tx = T::arbitrary(u)?;

        let (recoverable_sig, recovery_id) =
            signing_key.sign_prehash(tx.signature_hash().as_ref()).unwrap();
        let signature: Signature = (recoverable_sig, recovery_id).into();

        Ok(tx.into_signed(signature))
    }
}

#[cfg(feature = "serde")]
mod serde {
    use crate::transaction::RlpEcdsaEncodableTx;
    use alloc::borrow::Cow;
    use alloy_primitives::B256;
    use serde::{de::DeserializeOwned, Deserialize, Deserializer, Serialize, Serializer};

    #[derive(Serialize, Deserialize)]
    struct Signed<'a, T: Clone, Sig: Clone> {
        #[serde(flatten)]
        tx: Cow<'a, T>,
        #[serde(flatten)]
        signature: Cow<'a, Sig>,
        hash: Cow<'a, B256>,
    }

    impl<T> Serialize for super::Signed<T>
    where
        T: Clone + RlpEcdsaEncodableTx + Serialize,
    {
        fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
        where
            S: Serializer,
        {
            Signed {
                tx: Cow::Borrowed(&self.tx),
                signature: Cow::Borrowed(&self.signature),
                hash: Cow::Borrowed(self.hash()),
            }
            .serialize(serializer)
        }
    }

    impl<'de, T, Sig> Deserialize<'de> for super::Signed<T, Sig>
    where
        T: Clone + DeserializeOwned,
        Sig: Clone + DeserializeOwned,
    {
        fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
        where
            D: Deserializer<'de>,
        {
            Signed::<T, Sig>::deserialize(deserializer).map(|value| {
                Self::new_unchecked(
                    value.tx.into_owned(),
                    value.signature.into_owned(),
                    value.hash.into_owned(),
                )
            })
        }
    }
}