Adjust Bitcoin processor layout

processor/bitcoin/src/primitives/block.rs

@@ -0,0 +1,77 @@
+use core::fmt;
+use std::collections::HashMap;
+
+use ciphersuite::{Ciphersuite, Secp256k1};
+
+use bitcoin_serai::bitcoin::block::{Header, Block as BBlock};
+
+use serai_client::networks::bitcoin::Address;
+
+use serai_db::Db;
+use primitives::{ReceivedOutput, EventualityTracker};
+
+use crate::{hash_bytes, scan::scanner, output::Output, transaction::Eventuality};
+
+#[derive(Clone, Debug)]
+pub(crate) struct BlockHeader(pub(crate) Header);
+impl primitives::BlockHeader for BlockHeader {
+  fn id(&self) -> [u8; 32] {
+    hash_bytes(self.0.block_hash().to_raw_hash())
+  }
+  fn parent(&self) -> [u8; 32] {
+    hash_bytes(self.0.prev_blockhash.to_raw_hash())
+  }
+}
+
+#[derive(Clone)]
+pub(crate) struct Block<D: Db>(pub(crate) D, pub(crate) BBlock);
+impl<D: Db> fmt::Debug for Block<D> {
+  fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+    fmt.debug_struct("Block").field("1", &self.1).finish_non_exhaustive()
+  }
+}
+
+#[async_trait::async_trait]
+impl<D: Db> primitives::Block for Block<D> {
+  type Header = BlockHeader;
+
+  type Key = <Secp256k1 as Ciphersuite>::G;
+  type Address = Address;
+  type Output = Output;
+  type Eventuality = Eventuality;
+
+  fn id(&self) -> [u8; 32] {
+    primitives::BlockHeader::id(&BlockHeader(self.1.header))
+  }
+
+  fn scan_for_outputs_unordered(&self, key: Self::Key) -> Vec<Self::Output> {
+    let scanner = scanner(key);
+
+    let mut res = vec![];
+    // We skip the coinbase transaction as its burdened by maturity
+    for tx in &self.1.txdata[1 ..] {
+      for output in scanner.scan_transaction(tx) {
+        res.push(Output::new(&self.0, key, tx, output));
+      }
+    }
+    res
+  }
+
+  #[allow(clippy::type_complexity)]
+  fn check_for_eventuality_resolutions(
+    &self,
+    eventualities: &mut EventualityTracker<Self::Eventuality>,
+  ) -> HashMap<
+    <Self::Output as ReceivedOutput<Self::Key, Self::Address>>::TransactionId,
+    Self::Eventuality,
+  > {
+    let mut res = HashMap::new();
+    for tx in &self.1.txdata[1 ..] {
+      let id = hash_bytes(tx.compute_txid().to_raw_hash());
+      if let Some(eventuality) = eventualities.active_eventualities.remove(id.as_slice()) {
+        res.insert(id, eventuality);
+      }
+    }
+    res
+  }
+}

processor/bitcoin/src/primitives/mod.rs

@@ -0,0 +1,3 @@
+pub(crate) mod output;
+pub(crate) mod transaction;
+pub(crate) mod block;

processor/bitcoin/src/primitives/output.rs

@@ -0,0 +1,175 @@
+use std::io;
+
+use ciphersuite::{Ciphersuite, Secp256k1};
+
+use bitcoin_serai::{
+  bitcoin::{
+    hashes::Hash as HashTrait,
+    key::{Parity, XOnlyPublicKey},
+    consensus::Encodable,
+    script::Instruction,
+    transaction::Transaction,
+  },
+  wallet::ReceivedOutput as WalletOutput,
+};
+
+use scale::{Encode, Decode, IoReader};
+use borsh::{BorshSerialize, BorshDeserialize};
+use serai_db::Get;
+
+use serai_client::{
+  primitives::{Coin, Amount, Balance, ExternalAddress},
+  networks::bitcoin::Address,
+};
+
+use primitives::{OutputType, ReceivedOutput};
+
+use crate::scan::{offsets_for_key, presumed_origin, extract_serai_data};
+
+#[derive(Clone, PartialEq, Eq, Hash, Debug, Encode, Decode, BorshSerialize, BorshDeserialize)]
+pub(crate) struct OutputId([u8; 36]);
+impl Default for OutputId {
+  fn default() -> Self {
+    Self([0; 36])
+  }
+}
+impl AsRef<[u8]> for OutputId {
+  fn as_ref(&self) -> &[u8] {
+    self.0.as_ref()
+  }
+}
+impl AsMut<[u8]> for OutputId {
+  fn as_mut(&mut self) -> &mut [u8] {
+    self.0.as_mut()
+  }
+}
+
+#[derive(Clone, PartialEq, Eq, Debug)]
+pub(crate) struct Output {
+  kind: OutputType,
+  presumed_origin: Option<Address>,
+  pub(crate) output: WalletOutput,
+  data: Vec<u8>,
+}
+
+impl Output {
+  pub(crate) fn new(
+    getter: &impl Get,
+    key: <Secp256k1 as Ciphersuite>::G,
+    tx: &Transaction,
+    output: WalletOutput,
+  ) -> Self {
+    Self {
+      kind: offsets_for_key(key)
+        .into_iter()
+        .find_map(|(kind, offset)| (offset == output.offset()).then_some(kind))
+        .expect("scanned output for unknown offset"),
+      presumed_origin: presumed_origin(getter, tx),
+      output,
+      data: extract_serai_data(tx),
+    }
+  }
+
+  pub(crate) fn new_with_presumed_origin(
+    key: <Secp256k1 as Ciphersuite>::G,
+    tx: &Transaction,
+    presumed_origin: Option<Address>,
+    output: WalletOutput,
+  ) -> Self {
+    Self {
+      kind: offsets_for_key(key)
+        .into_iter()
+        .find_map(|(kind, offset)| (offset == output.offset()).then_some(kind))
+        .expect("scanned output for unknown offset"),
+      presumed_origin,
+      output,
+      data: extract_serai_data(tx),
+    }
+  }
+}
+
+impl ReceivedOutput<<Secp256k1 as Ciphersuite>::G, Address> for Output {
+  type Id = OutputId;
+  type TransactionId = [u8; 32];
+
+  fn kind(&self) -> OutputType {
+    self.kind
+  }
+
+  fn id(&self) -> Self::Id {
+    let mut id = OutputId::default();
+    self.output.outpoint().consensus_encode(&mut id.as_mut()).unwrap();
+    id
+  }
+
+  fn transaction_id(&self) -> Self::TransactionId {
+    let mut res = self.output.outpoint().txid.to_raw_hash().to_byte_array();
+    res.reverse();
+    res
+  }
+
+  fn key(&self) -> <Secp256k1 as Ciphersuite>::G {
+    // We read the key from the script pubkey so we don't have to independently store it
+    let script = &self.output.output().script_pubkey;
+
+    // These assumptions are safe since it's an output we successfully scanned
+    assert!(script.is_p2tr());
+    let Instruction::PushBytes(key) = script.instructions_minimal().last().unwrap().unwrap() else {
+      panic!("last item in v1 Taproot script wasn't bytes")
+    };
+    let key = XOnlyPublicKey::from_slice(key.as_ref())
+      .expect("last item in v1 Taproot script wasn't a valid x-only public key");
+
+    // Convert to a full key
+    let key = key.public_key(Parity::Even);
+    // Convert to a k256 key (from libsecp256k1)
+    let output_key = Secp256k1::read_G(&mut key.serialize().as_slice()).unwrap();
+    // The output's key minus the output's offset is the root key
+    output_key - (<Secp256k1 as Ciphersuite>::G::GENERATOR * self.output.offset())
+  }
+
+  fn presumed_origin(&self) -> Option<Address> {
+    self.presumed_origin.clone()
+  }
+
+  fn balance(&self) -> Balance {
+    Balance { coin: Coin::Bitcoin, amount: Amount(self.output.value()) }
+  }
+
+  fn data(&self) -> &[u8] {
+    &self.data
+  }
+
+  fn write<W: io::Write>(&self, writer: &mut W) -> io::Result<()> {
+    self.kind.write(writer)?;
+    let presumed_origin: Option<ExternalAddress> = self.presumed_origin.clone().map(Into::into);
+    writer.write_all(&presumed_origin.encode())?;
+    self.output.write(writer)?;
+    writer.write_all(&u16::try_from(self.data.len()).unwrap().to_le_bytes())?;
+    writer.write_all(&self.data)
+  }
+
+  fn read<R: io::Read>(mut reader: &mut R) -> io::Result<Self> {
+    Ok(Output {
+      kind: OutputType::read(reader)?,
+      presumed_origin: {
+        Option::<ExternalAddress>::decode(&mut IoReader(&mut reader))
+          .map_err(|e| io::Error::other(format!("couldn't decode ExternalAddress: {e:?}")))?
+          .map(|address| {
+            Address::try_from(address)
+              .map_err(|()| io::Error::other("couldn't decode Address from ExternalAddress"))
+          })
+          .transpose()?
+      },
+      output: WalletOutput::read(reader)?,
+      data: {
+        let mut data_len = [0; 2];
+        reader.read_exact(&mut data_len)?;
+
+        let mut data = vec![0; usize::from(u16::from_le_bytes(data_len))];
+        reader.read_exact(&mut data)?;
+        data
+      },
+    })
+  }
+}

processor/bitcoin/src/primitives/transaction.rs

@@ -0,0 +1,167 @@
+use std::io;
+
+use rand_core::{RngCore, CryptoRng};
+
+use transcript::{Transcript, RecommendedTranscript};
+use ciphersuite::Secp256k1;
+use frost::{dkg::ThresholdKeys, sign::PreprocessMachine};
+
+use bitcoin_serai::{
+  bitcoin::{
+    consensus::{Encodable, Decodable},
+    ScriptBuf, Transaction as BTransaction,
+  },
+  wallet::{
+    ReceivedOutput, TransactionError, SignableTransaction as BSignableTransaction,
+    TransactionMachine,
+  },
+};
+
+use borsh::{BorshSerialize, BorshDeserialize};
+
+use serai_client::networks::bitcoin::Address;
+
+use crate::output::OutputId;
+
+#[derive(Clone, Debug)]
+pub(crate) struct Transaction(pub(crate) BTransaction);
+
+impl From<BTransaction> for Transaction {
+  fn from(tx: BTransaction) -> Self {
+    Self(tx)
+  }
+}
+
+impl scheduler::Transaction for Transaction {
+  fn read(reader: &mut impl io::Read) -> io::Result<Self> {
+    let tx =
+      BTransaction::consensus_decode(&mut io::BufReader::new(reader)).map_err(io::Error::other)?;
+    Ok(Self(tx))
+  }
+  fn write(&self, writer: &mut impl io::Write) -> io::Result<()> {
+    let mut writer = io::BufWriter::new(writer);
+    self.0.consensus_encode(&mut writer)?;
+    writer.into_inner()?;
+    Ok(())
+  }
+}
+
+#[derive(Clone, Debug)]
+pub(crate) struct SignableTransaction {
+  pub(crate) inputs: Vec<ReceivedOutput>,
+  pub(crate) payments: Vec<(Address, u64)>,
+  pub(crate) change: Option<Address>,
+  pub(crate) fee_per_vbyte: u64,
+}
+
+impl SignableTransaction {
+  fn signable(self) -> Result<BSignableTransaction, TransactionError> {
+    BSignableTransaction::new(
+      self.inputs,
+      &self
+        .payments
+        .iter()
+        .cloned()
+        .map(|(address, amount)| (ScriptBuf::from(address), amount))
+        .collect::<Vec<_>>(),
+      self.change.map(ScriptBuf::from),
+      None,
+      self.fee_per_vbyte,
+    )
+  }
+}
+
+#[derive(Clone)]
+pub(crate) struct ClonableTransctionMachine(SignableTransaction, ThresholdKeys<Secp256k1>);
+impl PreprocessMachine for ClonableTransctionMachine {
+  type Preprocess = <TransactionMachine as PreprocessMachine>::Preprocess;
+  type Signature = <TransactionMachine as PreprocessMachine>::Signature;
+  type SignMachine = <TransactionMachine as PreprocessMachine>::SignMachine;
+
+  fn preprocess<R: RngCore + CryptoRng>(
+    self,
+    rng: &mut R,
+  ) -> (Self::SignMachine, Self::Preprocess) {
+    self
+      .0
+      .signable()
+      .expect("signing an invalid SignableTransaction")
+      .multisig(&self.1, RecommendedTranscript::new(b"Serai Processor Bitcoin Transaction"))
+      .expect("incorrect keys used for SignableTransaction")
+      .preprocess(rng)
+  }
+}
+
+impl scheduler::SignableTransaction for SignableTransaction {
+  type Transaction = Transaction;
+  type Ciphersuite = Secp256k1;
+  type PreprocessMachine = ClonableTransctionMachine;
+
+  fn read(reader: &mut impl io::Read) -> io::Result<Self> {
+    let inputs = {
+      let mut input_len = [0; 4];
+      reader.read_exact(&mut input_len)?;
+      let mut inputs = vec![];
+      for _ in 0 .. u32::from_le_bytes(input_len) {
+        inputs.push(ReceivedOutput::read(reader)?);
+      }
+      inputs
+    };
+
+    let payments = <_>::deserialize_reader(reader)?;
+    let change = <_>::deserialize_reader(reader)?;
+    let fee_per_vbyte = <_>::deserialize_reader(reader)?;
+
+    Ok(Self { inputs, payments, change, fee_per_vbyte })
+  }
+  fn write(&self, writer: &mut impl io::Write) -> io::Result<()> {
+    writer.write_all(&u32::try_from(self.inputs.len()).unwrap().to_le_bytes())?;
+    for input in &self.inputs {
+      input.write(writer)?;
+    }
+
+    self.payments.serialize(writer)?;
+    self.change.serialize(writer)?;
+    self.fee_per_vbyte.serialize(writer)?;
+
+    Ok(())
+  }
+
+  fn id(&self) -> [u8; 32] {
+    self.clone().signable().unwrap().txid()
+  }
+
+  fn sign(self, keys: ThresholdKeys<Self::Ciphersuite>) -> Self::PreprocessMachine {
+    ClonableTransctionMachine(self, keys)
+  }
+}
+
+#[derive(Clone, PartialEq, Eq, Debug, BorshSerialize, BorshDeserialize)]
+pub(crate) struct Eventuality {
+  pub(crate) txid: [u8; 32],
+  pub(crate) singular_spent_output: Option<OutputId>,
+}
+
+impl primitives::Eventuality for Eventuality {
+  type OutputId = OutputId;
+
+  fn id(&self) -> [u8; 32] {
+    self.txid
+  }
+
+  // We define the lookup as our ID since the resolving transaction only has a singular possible ID
+  fn lookup(&self) -> Vec<u8> {
+    self.txid.to_vec()
+  }
+
+  fn singular_spent_output(&self) -> Option<Self::OutputId> {
+    self.singular_spent_output.clone()
+  }
+
+  fn read(reader: &mut impl io::Read) -> io::Result<Self> {
+    Self::deserialize_reader(reader)
+  }
+  fn write(&self, writer: &mut impl io::Write) -> io::Result<()> {
+    self.serialize(writer)
+  }
+}