+//! Traits and utility impls which allow other parts of rust-lightning to interact with the
+//! blockchain.
+//!
+//! Includes traits for monitoring and receiving notifications of new blocks and block
+//! disconnections, transaction broadcasting, and feerate information requests.
+
use bitcoin::blockdata::block::{Block, BlockHeader};
use bitcoin::blockdata::transaction::Transaction;
use bitcoin::blockdata::script::Script;
-use bitcoin::util::hash::Sha256dHash;
-use std::sync::{Mutex,Weak,MutexGuard};
+use bitcoin::blockdata::constants::genesis_block;
+use bitcoin::util::hash::BitcoinHash;
+use bitcoin_hashes::sha256d::Hash as Sha256dHash;
+use bitcoin::network::constants::Network;
+
+use util::logger::Logger;
+
+use std::sync::{Mutex,Weak,MutexGuard,Arc};
use std::sync::atomic::{AtomicUsize, Ordering};
+use std::collections::HashSet;
+
+/// Used to give chain error details upstream
+pub enum ChainError {
+ /// Client doesn't support UTXO lookup (but the chain hash matches our genesis block hash)
+ NotSupported,
+ /// Chain isn't the one watched
+ NotWatched,
+ /// Tx doesn't exist or is unconfirmed
+ UnknownTx,
+}
/// An interface to request notification of certain scripts as they appear the
/// chain.
+///
/// Note that all of the functions implemented here *must* be reentrant-safe (obviously - they're
/// called from inside the library in response to ChainListener events, P2P events, or timer
/// events).
pub trait ChainWatchInterface: Sync + Send {
- /// Provides a scriptPubKey which much be watched for.
- fn install_watch_script(&self, script_pub_key: Script);
+ /// Provides a txid/random-scriptPubKey-in-the-tx which much be watched for.
+ fn install_watch_tx(&self, txid: &Sha256dHash, script_pub_key: &Script);
/// Provides an outpoint which must be watched for, providing any transactions which spend the
/// given outpoint.
/// Indicates that a listener needs to see all transactions.
fn watch_all_txn(&self);
+ /// Register the given listener to receive events. Only a weak pointer is provided and the
+ /// registration should be freed once that pointer expires.
fn register_listener(&self, listener: Weak<ChainListener>);
//TODO: unregister
+
+ /// Gets the script and value in satoshis for a given unspent transaction output given a
+ /// short_channel_id (aka unspent_tx_output_identier). For BTC/tBTC channels the top three
+ /// bytes are the block height, the next 3 the transaction index within the block, and the
+ /// final two the output within the transaction.
+ fn get_chain_utxo(&self, genesis_hash: Sha256dHash, unspent_tx_output_identifier: u64) -> Result<(Script, u64), ChainError>;
}
/// An interface to send a transaction to the Bitcoin network.
/// A trait indicating a desire to listen for events from the chain
pub trait ChainListener: Sync + Send {
/// Notifies a listener that a block was connected.
- /// Note that if a new script/transaction is watched during a block_connected call, the block
- /// *must* be re-scanned with the new script/transaction and block_connected should be called
- /// again with the same header and (at least) the new transactions.
+ /// Note that if a new transaction/outpoint is watched during a block_connected call, the block
+ /// *must* be re-scanned with the new transaction/outpoints and block_connected should be
+ /// called again with the same header and (at least) the new transactions.
+ ///
+ /// Note that if non-new transaction/outpoints may be registered during a call, a second call
+ /// *must not* happen.
+ ///
/// This also means those counting confirmations using block_connected callbacks should watch
/// for duplicate headers and not count them towards confirmations!
fn block_connected(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]);
/// Notifies a listener that a block was disconnected.
/// Unlike block_connected, this *must* never be called twice for the same disconnect event.
- fn block_disconnected(&self, header: &BlockHeader);
+ /// Height must be the one of the block which was disconnected (not new height of the best chain)
+ fn block_disconnected(&self, header: &BlockHeader, disconnected_height: u32);
}
+/// An enum that represents the speed at which we want a transaction to confirm used for feerate
+/// estimation.
pub enum ConfirmationTarget {
+ /// We are happy with this transaction confirming slowly when feerate drops some.
Background,
+ /// We'd like this transaction to confirm without major delay, but 12-18 blocks is fine.
Normal,
+ /// We'd like this transaction to confirm in the next few blocks.
HighPriority,
}
/// A trait which should be implemented to provide feerate information on a number of time
/// horizons.
+///
/// Note that all of the functions implemented here *must* be reentrant-safe (obviously - they're
/// called from inside the library in response to ChainListener events, P2P events, or timer
/// events).
pub trait FeeEstimator: Sync + Send {
- fn get_est_sat_per_vbyte(&self, confirmation_target: ConfirmationTarget) -> u64;
+ /// Gets estimated satoshis of fee required per 1000 Weight-Units.
+ ///
+ /// Must be no smaller than 253 (ie 1 satoshi-per-byte rounded up to ensure later round-downs
+ /// don't put us below 1 satoshi-per-byte).
+ ///
+ /// This translates to:
+ /// * satoshis-per-byte * 250
+ /// * ceil(satoshis-per-kbyte / 4)
+ fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u64;
+}
+
+/// Utility for tracking registered txn/outpoints and checking for matches
+pub struct ChainWatchedUtil {
+ watch_all: bool,
+
+ // We are more conservative in matching during testing to ensure everything matches *exactly*,
+ // even though during normal runtime we take more optimized match approaches...
+ #[cfg(test)]
+ watched_txn: HashSet<(Sha256dHash, Script)>,
+ #[cfg(not(test))]
+ watched_txn: HashSet<Script>,
+
+ watched_outpoints: HashSet<(Sha256dHash, u32)>,
+}
+
+impl ChainWatchedUtil {
+ /// Constructs an empty (watches nothing) ChainWatchedUtil
+ pub fn new() -> Self {
+ Self {
+ watch_all: false,
+ watched_txn: HashSet::new(),
+ watched_outpoints: HashSet::new(),
+ }
+ }
+
+ /// Registers a tx for monitoring, returning true if it was a new tx and false if we'd already
+ /// been watching for it.
+ pub fn register_tx(&mut self, txid: &Sha256dHash, script_pub_key: &Script) -> bool {
+ if self.watch_all { return false; }
+ #[cfg(test)]
+ {
+ self.watched_txn.insert((txid.clone(), script_pub_key.clone()))
+ }
+ #[cfg(not(test))]
+ {
+ let _tx_unused = txid; // It's used in cfg(test), though
+ self.watched_txn.insert(script_pub_key.clone())
+ }
+ }
+
+ /// Registers an outpoint for monitoring, returning true if it was a new outpoint and false if
+ /// we'd already been watching for it
+ pub fn register_outpoint(&mut self, outpoint: (Sha256dHash, u32), _script_pub_key: &Script) -> bool {
+ if self.watch_all { return false; }
+ self.watched_outpoints.insert(outpoint)
+ }
+
+ /// Sets us to match all transactions, returning true if this is a new setting and false if
+ /// we'd already been set to match everything.
+ pub fn watch_all(&mut self) -> bool {
+ if self.watch_all { return false; }
+ self.watch_all = true;
+ true
+ }
+
+ /// Checks if a given transaction matches the current filter.
+ pub fn does_match_tx(&self, tx: &Transaction) -> bool {
+ if self.watch_all {
+ return true;
+ }
+ for out in tx.output.iter() {
+ #[cfg(test)]
+ for &(ref txid, ref script) in self.watched_txn.iter() {
+ if *script == out.script_pubkey {
+ if tx.txid() == *txid {
+ return true;
+ }
+ }
+ }
+ #[cfg(not(test))]
+ for script in self.watched_txn.iter() {
+ if *script == out.script_pubkey {
+ return true;
+ }
+ }
+ }
+ for input in tx.input.iter() {
+ for outpoint in self.watched_outpoints.iter() {
+ let &(outpoint_hash, outpoint_index) = outpoint;
+ if outpoint_hash == input.previous_output.txid && outpoint_index == input.previous_output.vout {
+ return true;
+ }
+ }
+ }
+ false
+ }
}
/// Utility to capture some common parts of ChainWatchInterface implementors.
+///
/// Keeping a local copy of this in a ChainWatchInterface implementor is likely useful.
pub struct ChainWatchInterfaceUtil {
- watched: Mutex<(Vec<Script>, Vec<(Sha256dHash, u32)>, bool)>, //TODO: Something clever to optimize this
+ network: Network,
+ watched: Mutex<ChainWatchedUtil>,
listeners: Mutex<Vec<Weak<ChainListener>>>,
- reentered: AtomicUsize
+ reentered: AtomicUsize,
+ logger: Arc<Logger>,
}
/// Register listener
impl ChainWatchInterface for ChainWatchInterfaceUtil {
- fn install_watch_script(&self, script_pub_key: Script) {
+ fn install_watch_tx(&self, txid: &Sha256dHash, script_pub_key: &Script) {
let mut watched = self.watched.lock().unwrap();
- watched.0.push(Script::from(script_pub_key));
- self.reentered.fetch_add(1, Ordering::Relaxed);
+ if watched.register_tx(txid, script_pub_key) {
+ self.reentered.fetch_add(1, Ordering::Relaxed);
+ }
}
- fn install_watch_outpoint(&self, outpoint: (Sha256dHash, u32), _out_script: &Script) {
+ fn install_watch_outpoint(&self, outpoint: (Sha256dHash, u32), out_script: &Script) {
let mut watched = self.watched.lock().unwrap();
- watched.1.push(outpoint);
- self.reentered.fetch_add(1, Ordering::Relaxed);
+ if watched.register_outpoint(outpoint, out_script) {
+ self.reentered.fetch_add(1, Ordering::Relaxed);
+ }
}
fn watch_all_txn(&self) {
let mut watched = self.watched.lock().unwrap();
- watched.2 = true;
- self.reentered.fetch_add(1, Ordering::Relaxed);
+ if watched.watch_all() {
+ self.reentered.fetch_add(1, Ordering::Relaxed);
+ }
}
fn register_listener(&self, listener: Weak<ChainListener>) {
let mut vec = self.listeners.lock().unwrap();
vec.push(listener);
}
+
+ fn get_chain_utxo(&self, genesis_hash: Sha256dHash, _unspent_tx_output_identifier: u64) -> Result<(Script, u64), ChainError> {
+ if genesis_hash != genesis_block(self.network).header.bitcoin_hash() {
+ return Err(ChainError::NotWatched);
+ }
+ Err(ChainError::NotSupported)
+ }
}
impl ChainWatchInterfaceUtil {
- pub fn new() -> ChainWatchInterfaceUtil {
+ /// Creates a new ChainWatchInterfaceUtil for the given network
+ pub fn new(network: Network, logger: Arc<Logger>) -> ChainWatchInterfaceUtil {
ChainWatchInterfaceUtil {
- watched: Mutex::new((Vec::new(), Vec::new(), false)),
+ network: network,
+ watched: Mutex::new(ChainWatchedUtil::new()),
listeners: Mutex::new(Vec::new()),
- reentered: AtomicUsize::new(1)
+ reentered: AtomicUsize::new(1),
+ logger: logger,
}
}
- /// Notify listeners that a block was connected.
+ /// Notify listeners that a block was connected given a full, unfiltered block.
+ ///
/// Handles re-scanning the block and calling block_connected again if listeners register new
/// watch data during the callbacks for you (see ChainListener::block_connected for more info).
pub fn block_connected_with_filtering(&self, block: &Block, height: u32) {
}
/// Notify listeners that a block was disconnected.
- pub fn block_disconnected(&self, header: &BlockHeader) {
+ pub fn block_disconnected(&self, header: &BlockHeader, disconnected_height: u32) {
let listeners = self.listeners.lock().unwrap().clone();
for listener in listeners.iter() {
match listener.upgrade() {
- Some(arc) => arc.block_disconnected(header),
+ Some(arc) => arc.block_disconnected(&header, disconnected_height),
None => ()
}
}
}
- /// Notify listeners that a block was connected.
+ /// Notify listeners that a block was connected, given pre-filtered list of transactions in the
+ /// block which matched the filter (probably using does_match_tx).
+ ///
/// Returns true if notified listeners registered additional watch data (implying that the
/// block must be re-scanned and this function called again prior to further block_connected
/// calls, see ChainListener::block_connected for more info).
self.does_match_tx_unguarded (tx, &watched)
}
- fn does_match_tx_unguarded(&self, tx: &Transaction, watched: &MutexGuard<(Vec<Script>, Vec<(Sha256dHash, u32)>, bool)>) -> bool {
- if watched.2 {
- return true;
- }
- for out in tx.output.iter() {
- for script in watched.0.iter() {
- if script[..] == out.script_pubkey[..] {
- return true;
- }
- }
- }
- for input in tx.input.iter() {
- for outpoint in watched.1.iter() {
- let &(outpoint_hash, outpoint_index) = outpoint;
- if outpoint_hash == input.prev_hash && outpoint_index == input.prev_index {
- return true;
- }
- }
- }
- false
+ fn does_match_tx_unguarded(&self, tx: &Transaction, watched: &MutexGuard<ChainWatchedUtil>) -> bool {
+ watched.does_match_tx(tx)
}
}
projects / rust-lightning / blobdiff