Add initial chain access implementation

src/access.rs

@@ -0,0 +1,325 @@
+use crate::error::LdkLiteError as Error;
+#[allow(unused_imports)]
+use crate::logger::{
+	log_error, log_given_level, log_info, log_internal, log_trace, log_warn, FilesystemLogger,
+	Logger,
+};
+
+use lightning::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator};
+use lightning::chain::WatchedOutput;
+use lightning::chain::{Confirm, Filter};
+
+use bdk::blockchain::{Blockchain, EsploraBlockchain, GetBlockHash, GetHeight, GetTx};
+use bdk::database::BatchDatabase;
+use bdk::wallet::AddressIndex;
+use bdk::{SignOptions, SyncOptions};
+
+use bitcoin::{BlockHash, Script, Transaction, Txid};
+
+use std::sync::{Arc, Mutex};
+
+pub struct LdkLiteChainAccess<D>
+where
+	D: BatchDatabase,
+{
+	blockchain: EsploraBlockchain,
+	wallet: Mutex<bdk::Wallet<D>>,
+	queued_transactions: Mutex<Vec<Txid>>,
+	watched_transactions: Mutex<Vec<Txid>>,
+	queued_outputs: Mutex<Vec<WatchedOutput>>,
+	watched_outputs: Mutex<Vec<WatchedOutput>>,
+	last_sync_height: Mutex<Option<u32>>,
+	logger: Arc<FilesystemLogger>,
+}
+
+impl<D> LdkLiteChainAccess<D>
+where
+	D: BatchDatabase,
+{
+	pub(crate) fn new(
+		blockchain: EsploraBlockchain, wallet: bdk::Wallet<D>, logger: Arc<FilesystemLogger>,
+	) -> Self {
+		let wallet = Mutex::new(wallet);
+		let watched_transactions = Mutex::new(Vec::new());
+		let queued_transactions = Mutex::new(Vec::new());
+		let watched_outputs = Mutex::new(Vec::new());
+		let queued_outputs = Mutex::new(Vec::new());
+		let last_sync_height = Mutex::new(None);
+		Self {
+			blockchain,
+			wallet,
+			queued_transactions,
+			watched_transactions,
+			queued_outputs,
+			watched_outputs,
+			last_sync_height,
+			logger,
+		}
+	}
+
+	pub(crate) fn sync_wallet(&self) -> Result<(), Error> {
+		let sync_options = SyncOptions { progress: None };
+
+		self.wallet
+			.lock()
+			.unwrap()
+			.sync(&self.blockchain, sync_options)
+			.map_err(|e| Error::Bdk(e))?;
+
+		Ok(())
+	}
+
+	pub(crate) fn sync(&self, confirmables: Vec<&(dyn Confirm + Sync)>) -> Result<(), Error> {
+		let client = &*self.blockchain;
+
+		let cur_height = client.get_height()?;
+
+		let mut locked_last_sync_height = self.last_sync_height.lock().unwrap();
+		if cur_height >= locked_last_sync_height.unwrap_or(0) {
+			{
+				// First, inform the interface of the new block.
+				let cur_block_header = client.get_header(cur_height)?;
+				for c in &confirmables {
+					c.best_block_updated(&cur_block_header, cur_height);
+				}
+
+				*locked_last_sync_height = Some(cur_height);
+			}
+
+			{
+				// First, check the confirmation status of registered transactions as well as the
+				// status of dependent transactions of registered outputs.
+				let mut locked_queued_transactions = self.queued_transactions.lock().unwrap();
+				let mut locked_queued_outputs = self.queued_outputs.lock().unwrap();
+				let mut locked_watched_transactions = self.watched_transactions.lock().unwrap();
+				let mut locked_watched_outputs = self.watched_outputs.lock().unwrap();
+
+				let mut confirmed_txs = Vec::new();
+
+				// Check in the current queue, as well as in registered transactions leftover from
+				// previous iterations.
+				let mut registered_txs: Vec<Txid> = locked_watched_transactions
+					.iter()
+					.chain(locked_queued_transactions.iter())
+					.cloned()
+					.collect();
+
+				registered_txs.sort_unstable_by(|txid1, txid2| txid1.cmp(&txid2));
+				registered_txs.dedup_by(|txid1, txid2| txid1.eq(&txid2));
+
+				// Remember all registered but unconfirmed transactions for future processing.
+				let mut unconfirmed_registered_txs = Vec::new();
+
+				for txid in registered_txs {
+					if let Some(tx_status) = client.get_tx_status(&txid)? {
+						if tx_status.confirmed {
+							if let Some(tx) = client.get_tx(&txid)? {
+								if let Some(block_height) = tx_status.block_height {
+									let block_header = client.get_header(block_height)?;
+									if let Some(merkle_proof) = client.get_merkle_proof(&txid)? {
+										confirmed_txs.push((
+											tx,
+											block_height,
+											block_header,
+											merkle_proof.pos,
+										));
+										continue;
+									}
+								}
+							}
+						}
+					}
+					unconfirmed_registered_txs.push(txid);
+				}
+
+				// Check all registered outputs for dependent spending transactions.
+				let registered_outputs: Vec<WatchedOutput> = locked_watched_outputs
+					.iter()
+					.chain(locked_queued_outputs.iter())
+					.cloned()
+					.collect();
+
+				// Remember all registered outputs that haven't been spent for future processing.
+				let mut unspent_registered_outputs = Vec::new();
+
+				for output in registered_outputs {
+					if let Some(output_status) = client
+						.get_output_status(&output.outpoint.txid, output.outpoint.index as u64)?
+					{
+						if output_status.spent {
+							if let Some(spending_tx_status) = output_status.status {
+								if spending_tx_status.confirmed {
+									let spending_txid = output_status.txid.unwrap();
+									if let Some(spending_tx) = client.get_tx(&spending_txid)? {
+										let block_height = spending_tx_status.block_height.unwrap();
+										let block_header = client.get_header(block_height)?;
+										if let Some(merkle_proof) =
+											client.get_merkle_proof(&spending_txid)?
+										{
+											confirmed_txs.push((
+												spending_tx,
+												block_height,
+												block_header,
+												merkle_proof.pos,
+											));
+											continue;
+										}
+									}
+								}
+							}
+						}
+					}
+					unspent_registered_outputs.push(output);
+				}
+
+				// Sort all confirmed transactions by block height and feed them to the interface
+				// in order.
+				confirmed_txs.sort_unstable_by(
+					|(_, block_height1, _, _), (_, block_height2, _, _)| {
+						block_height1.cmp(&block_height2)
+					},
+				);
+				for (tx, block_height, block_header, pos) in confirmed_txs {
+					for c in &confirmables {
+						c.transactions_confirmed(&block_header, &[(pos, &tx)], block_height);
+					}
+				}
+
+				*locked_watched_transactions = unconfirmed_registered_txs;
+				*locked_queued_transactions = Vec::new();
+				*locked_watched_outputs = unspent_registered_outputs;
+				*locked_queued_outputs = Vec::new();
+			}
+
+			{
+				// Query the interface for relevant txids and check whether they have been
+				// reorged-out of the chain.
+				let unconfirmed_txids = confirmables
+					.iter()
+					.flat_map(|c| c.get_relevant_txids())
+					.filter(|txid| {
+						client
+							.get_tx_status(txid)
+							.ok()
+							.unwrap_or(None)
+							.map_or(true, |status| !status.confirmed)
+					})
+					.collect::<Vec<Txid>>();
+
+				// Mark all relevant unconfirmed transactions as unconfirmed.
+				for txid in &unconfirmed_txids {
+					for c in &confirmables {
+						c.transaction_unconfirmed(txid);
+					}
+				}
+			}
+		}
+
+		// TODO: check whether new outputs have been registered by now and process them
+		Ok(())
+	}
+
+	pub(crate) fn create_funding_transaction(
+		&self, output_script: &Script, value_sats: u64, confirmation_target: ConfirmationTarget,
+	) -> Result<Transaction, Error> {
+		let num_blocks = num_blocks_from_conf_target(confirmation_target);
+		let fee_rate = self.blockchain.estimate_fee(num_blocks)?;
+
+		let locked_wallet = self.wallet.lock().unwrap();
+		let mut tx_builder = locked_wallet.build_tx();
+
+		tx_builder.add_recipient(output_script.clone(), value_sats).fee_rate(fee_rate).enable_rbf();
+
+		let (mut psbt, _) = tx_builder.finish()?;
+		log_trace!(self.logger, "Created funding PSBT: {:?}", psbt);
+
+		// We double-check that no inputs try to spend non-witness outputs. As we use a SegWit
+		// wallet descriptor this technically shouldn't ever happen, but better safe than sorry.
+		for input in &psbt.inputs {
+			if input.witness_utxo.is_none() {
+				return Err(Error::FundingTxNonWitnessOuputSpend);
+			}
+		}
+
+		let finalized = locked_wallet.sign(&mut psbt, SignOptions::default())?;
+		if !finalized {
+			return Err(Error::FundingTxNotFinalized);
+		}
+
+		Ok(psbt.extract_tx())
+	}
+
+	pub(crate) fn get_new_address(&self) -> Result<bitcoin::Address, Error> {
+		let address_info = self.wallet.lock().unwrap().get_address(AddressIndex::New)?;
+		Ok(address_info.address)
+	}
+}
+
+impl<D> FeeEstimator for LdkLiteChainAccess<D>
+where
+	D: BatchDatabase,
+{
+	fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u32 {
+		let num_blocks = num_blocks_from_conf_target(confirmation_target);
+		self.blockchain.estimate_fee(num_blocks).map_or(253, |fee_rate| fee_rate.fee_wu(1000))
+			as u32
+	}
+}
+
+impl<D> BroadcasterInterface for LdkLiteChainAccess<D>
+where
+	D: BatchDatabase,
+{
+	fn broadcast_transaction(&self, tx: &Transaction) {
+		self.blockchain.broadcast(tx).ok();
+	}
+}
+
+impl<D> Filter for LdkLiteChainAccess<D>
+where
+	D: BatchDatabase,
+{
+	fn register_tx(&self, txid: &Txid, _script_pubkey: &Script) {
+		self.queued_transactions.lock().unwrap().push(*txid);
+	}
+
+	fn register_output(&self, output: WatchedOutput) -> Option<(usize, Transaction)> {
+		self.queued_outputs.lock().unwrap().push(output);
+		return None;
+	}
+}
+
+impl<D> GetHeight for LdkLiteChainAccess<D>
+where
+	D: BatchDatabase,
+{
+	fn get_height(&self) -> Result<u32, bdk::Error> {
+		self.blockchain.get_height()
+	}
+}
+
+impl<D> GetBlockHash for LdkLiteChainAccess<D>
+where
+	D: BatchDatabase,
+{
+	fn get_block_hash(&self, height: u64) -> Result<BlockHash, bdk::Error> {
+		self.blockchain.get_block_hash(height)
+	}
+}
+
+impl<D> GetTx for LdkLiteChainAccess<D>
+where
+	D: BatchDatabase,
+{
+	fn get_tx(&self, txid: &Txid) -> Result<Option<Transaction>, bdk::Error> {
+		self.blockchain.get_tx(txid)
+	}
+}
+
+fn num_blocks_from_conf_target(confirmation_target: ConfirmationTarget) -> usize {
+	match confirmation_target {
+		ConfirmationTarget::Background => 6,
+		ConfirmationTarget::Normal => 3,
+		ConfirmationTarget::HighPriority => 1,
+	}
+}