1 use bitcoin::blockdata::block::{Block, BlockHeader};
2 use bitcoin::blockdata::transaction::Transaction;
3 use bitcoin::blockdata::script::Script;
4 use bitcoin::blockdata::constants::genesis_block;
5 use bitcoin::util::hash::Sha256dHash;
6 use bitcoin::network::constants::Network;
7 use bitcoin::network::serialize::BitcoinHash;
9 use util::logger::Logger;
11 use std::sync::{Mutex,Weak,MutexGuard,Arc};
12 use std::sync::atomic::{AtomicUsize, Ordering};
13 use std::collections::HashSet;
15 /// Used to give chain error details upstream
17 /// Client doesn't support UTXO lookup (but the chain hash matches our genesis block hash)
19 /// Chain isn't the one watched
21 /// Tx doesn't exist or is unconfirmed
25 /// An interface to request notification of certain scripts as they appear the
27 /// Note that all of the functions implemented here *must* be reentrant-safe (obviously - they're
28 /// called from inside the library in response to ChainListener events, P2P events, or timer
30 pub trait ChainWatchInterface: Sync + Send {
31 /// Provides a txid/random-scriptPubKey-in-the-tx which much be watched for.
32 fn install_watch_tx(&self, txid: &Sha256dHash, script_pub_key: &Script);
34 /// Provides an outpoint which must be watched for, providing any transactions which spend the
36 fn install_watch_outpoint(&self, outpoint: (Sha256dHash, u32), out_script: &Script);
38 /// Indicates that a listener needs to see all transactions.
39 fn watch_all_txn(&self);
41 fn register_listener(&self, listener: Weak<ChainListener>);
44 /// Gets the script and value in satoshis for a given unspent transaction output given a
45 /// short_channel_id (aka unspent_tx_output_identier). For BTC/tBTC channels the top three
46 /// bytes are the block height, the next 3 the transaction index within the block, and the
47 /// final two the output within the transaction.
48 fn get_chain_utxo(&self, genesis_hash: Sha256dHash, unspent_tx_output_identifier: u64) -> Result<(Script, u64), ChainError>;
51 /// An interface to send a transaction to the Bitcoin network.
52 pub trait BroadcasterInterface: Sync + Send {
53 /// Sends a transaction out to (hopefully) be mined.
54 fn broadcast_transaction(&self, tx: &Transaction);
57 /// A trait indicating a desire to listen for events from the chain
58 pub trait ChainListener: Sync + Send {
59 /// Notifies a listener that a block was connected.
60 /// Note that if a new transaction/outpoint is watched during a block_connected call, the block
61 /// *must* be re-scanned with the new transaction/outpoints and block_connected should be
62 /// called again with the same header and (at least) the new transactions.
63 /// Note that if non-new transaction/outpoints may be registered during a call, a second call
64 /// *must not* happen.
65 /// This also means those counting confirmations using block_connected callbacks should watch
66 /// for duplicate headers and not count them towards confirmations!
67 fn block_connected(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]);
68 /// Notifies a listener that a block was disconnected.
69 /// Unlike block_connected, this *must* never be called twice for the same disconnect event.
70 fn block_disconnected(&self, header: &BlockHeader);
73 /// An enum that represents the speed at which we want a transaction to confirm used for feerate
75 pub enum ConfirmationTarget {
76 /// We are happy with this transaction confirming slowly when feerate drops some.
78 /// We'd like this transaction to confirm without major delay, but 12-18 blocks is fine.
80 /// We'd like this transaction to confirm in the next few blocks.
84 /// A trait which should be implemented to provide feerate information on a number of time
86 /// Note that all of the functions implemented here *must* be reentrant-safe (obviously - they're
87 /// called from inside the library in response to ChainListener events, P2P events, or timer
89 pub trait FeeEstimator: Sync + Send {
90 /// Gets estimated satoshis of fee required per 1000 Weight-Units. This translates to:
91 /// * satoshis-per-byte * 250
92 /// * ceil(satoshis-per-kbyte / 4)
93 /// Must be no smaller than 253 (ie 1 satoshi-per-byte rounded up to ensure later round-downs
94 /// don't put us below 1 satoshi-per-byte).
95 fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u64;
98 /// Utility for tracking registered txn/outpoints and checking for matches
99 pub struct ChainWatchedUtil {
102 // We are more conservative in matching during testing to ensure everything matches *exactly*,
103 // even though during normal runtime we take more optimized match approaches...
105 watched_txn: HashSet<(Sha256dHash, Script)>,
107 watched_txn: HashSet<Script>,
109 watched_outpoints: HashSet<(Sha256dHash, u32)>,
112 impl ChainWatchedUtil {
113 /// Constructs an empty (watches nothing) ChainWatchedUtil
114 pub fn new() -> Self {
117 watched_txn: HashSet::new(),
118 watched_outpoints: HashSet::new(),
122 /// Registers a tx for monitoring, returning true if it was a new tx and false if we'd already
123 /// been watching for it.
124 pub fn register_tx(&mut self, txid: &Sha256dHash, script_pub_key: &Script) -> bool {
125 if self.watch_all { return false; }
128 self.watched_txn.insert((txid.clone(), script_pub_key.clone()))
132 let _tx_unused = txid; // Its used in cfg(test), though
133 self.watched_txn.insert(script_pub_key.clone())
137 /// Registers an outpoint for monitoring, returning true if it was a new outpoint and false if
138 /// we'd already been watching for it
139 pub fn register_outpoint(&mut self, outpoint: (Sha256dHash, u32), _script_pub_key: &Script) -> bool {
140 if self.watch_all { return false; }
141 self.watched_outpoints.insert(outpoint)
144 /// Sets us to match all transactions, returning true if this is a new setting anf false if
145 /// we'd already been set to match everything.
146 pub fn watch_all(&mut self) -> bool {
147 if self.watch_all { return false; }
148 self.watch_all = true;
152 /// Checks if a given transaction matches the current filter.
153 pub fn does_match_tx(&self, tx: &Transaction) -> bool {
157 for out in tx.output.iter() {
159 for &(ref txid, ref script) in self.watched_txn.iter() {
160 if *script == out.script_pubkey {
161 if tx.txid() == *txid {
167 for script in self.watched_txn.iter() {
168 if *script == out.script_pubkey {
173 for input in tx.input.iter() {
174 for outpoint in self.watched_outpoints.iter() {
175 let &(outpoint_hash, outpoint_index) = outpoint;
176 if outpoint_hash == input.previous_output.txid && outpoint_index == input.previous_output.vout {
185 /// Utility to capture some common parts of ChainWatchInterface implementors.
186 /// Keeping a local copy of this in a ChainWatchInterface implementor is likely useful.
187 pub struct ChainWatchInterfaceUtil {
189 watched: Mutex<ChainWatchedUtil>,
190 listeners: Mutex<Vec<Weak<ChainListener>>>,
191 reentered: AtomicUsize,
195 /// Register listener
196 impl ChainWatchInterface for ChainWatchInterfaceUtil {
197 fn install_watch_tx(&self, txid: &Sha256dHash, script_pub_key: &Script) {
198 let mut watched = self.watched.lock().unwrap();
199 if watched.register_tx(txid, script_pub_key) {
200 self.reentered.fetch_add(1, Ordering::Relaxed);
204 fn install_watch_outpoint(&self, outpoint: (Sha256dHash, u32), out_script: &Script) {
205 let mut watched = self.watched.lock().unwrap();
206 if watched.register_outpoint(outpoint, out_script) {
207 self.reentered.fetch_add(1, Ordering::Relaxed);
211 fn watch_all_txn(&self) {
212 let mut watched = self.watched.lock().unwrap();
213 if watched.watch_all() {
214 self.reentered.fetch_add(1, Ordering::Relaxed);
218 fn register_listener(&self, listener: Weak<ChainListener>) {
219 let mut vec = self.listeners.lock().unwrap();
223 fn get_chain_utxo(&self, genesis_hash: Sha256dHash, _unspent_tx_output_identifier: u64) -> Result<(Script, u64), ChainError> {
224 if genesis_hash != genesis_block(self.network).header.bitcoin_hash() {
225 return Err(ChainError::NotWatched);
227 Err(ChainError::NotSupported)
231 impl ChainWatchInterfaceUtil {
232 pub fn new(network: Network, logger: Arc<Logger>) -> ChainWatchInterfaceUtil {
233 ChainWatchInterfaceUtil {
235 watched: Mutex::new(ChainWatchedUtil::new()),
236 listeners: Mutex::new(Vec::new()),
237 reentered: AtomicUsize::new(1),
242 /// Notify listeners that a block was connected given a full, unfiltered block.
243 /// Handles re-scanning the block and calling block_connected again if listeners register new
244 /// watch data during the callbacks for you (see ChainListener::block_connected for more info).
245 pub fn block_connected_with_filtering(&self, block: &Block, height: u32) {
246 let mut reentered = true;
248 let mut matched = Vec::new();
249 let mut matched_index = Vec::new();
251 let watched = self.watched.lock().unwrap();
252 for (index, transaction) in block.txdata.iter().enumerate() {
253 if self.does_match_tx_unguarded(transaction, &watched) {
254 matched.push(transaction);
255 matched_index.push(index as u32);
259 reentered = self.block_connected_checked(&block.header, height, matched.as_slice(), matched_index.as_slice());
263 /// Notify listeners that a block was disconnected.
264 pub fn block_disconnected(&self, header: &BlockHeader) {
265 let listeners = self.listeners.lock().unwrap().clone();
266 for listener in listeners.iter() {
267 match listener.upgrade() {
268 Some(arc) => arc.block_disconnected(header),
274 /// Notify listeners that a block was connected, given pre-filtered list of transactions in the
275 /// block which matched the filter (probably using does_match_tx).
276 /// Returns true if notified listeners registered additional watch data (implying that the
277 /// block must be re-scanned and this function called again prior to further block_connected
278 /// calls, see ChainListener::block_connected for more info).
279 pub fn block_connected_checked(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]) -> bool {
280 let last_seen = self.reentered.load(Ordering::Relaxed);
282 let listeners = self.listeners.lock().unwrap().clone();
283 for listener in listeners.iter() {
284 match listener.upgrade() {
285 Some(arc) => arc.block_connected(header, height, txn_matched, indexes_of_txn_matched),
289 return last_seen != self.reentered.load(Ordering::Relaxed);
292 /// Checks if a given transaction matches the current filter.
293 pub fn does_match_tx(&self, tx: &Transaction) -> bool {
294 let watched = self.watched.lock().unwrap();
295 self.does_match_tx_unguarded (tx, &watched)
298 fn does_match_tx_unguarded(&self, tx: &Transaction, watched: &MutexGuard<ChainWatchedUtil>) -> bool {
299 watched.does_match_tx(tx)