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;
8 use util::logger::Logger;
9 use std::sync::{Mutex,Weak,MutexGuard,Arc};
10 use std::sync::atomic::{AtomicUsize, Ordering};
12 /// Used to give chain error details upstream
14 /// Client doesn't support UTXO lookup (but the chain hash matches our genesis block hash)
16 /// Chain isn't the one watched
18 /// Tx doesn't exist or is unconfirmed
22 /// An interface to request notification of certain scripts as they appear the
24 /// Note that all of the functions implemented here *must* be reentrant-safe (obviously - they're
25 /// called from inside the library in response to ChainListener events, P2P events, or timer
27 pub trait ChainWatchInterface: Sync + Send {
28 /// Provides a scriptPubKey which much be watched for.
29 fn install_watch_script(&self, script_pub_key: &Script);
31 /// Provides an outpoint which must be watched for, providing any transactions which spend the
33 fn install_watch_outpoint(&self, outpoint: (Sha256dHash, u32), out_script: &Script);
35 /// Indicates that a listener needs to see all transactions.
36 fn watch_all_txn(&self);
38 fn register_listener(&self, listener: Weak<ChainListener>);
41 /// Gets the script and value in satoshis for a given unspent transaction output given a
42 /// short_channel_id (aka unspent_tx_output_identier). For BTC/tBTC channels the top three
43 /// bytes are the block height, the next 3 the transaction index within the block, and the
44 /// final two the output within the transaction.
45 fn get_chain_utxo(&self, genesis_hash: Sha256dHash, unspent_tx_output_identifier: u64) -> Result<(Script, u64), ChainError>;
48 /// An interface to send a transaction to the Bitcoin network.
49 pub trait BroadcasterInterface: Sync + Send {
50 /// Sends a transaction out to (hopefully) be mined.
51 fn broadcast_transaction(&self, tx: &Transaction);
54 /// A trait indicating a desire to listen for events from the chain
55 pub trait ChainListener: Sync + Send {
56 /// Notifies a listener that a block was connected.
57 /// Note that if a new script/transaction is watched during a block_connected call, the block
58 /// *must* be re-scanned with the new script/transaction and block_connected should be called
59 /// again with the same header and (at least) the new transactions.
60 /// This also means those counting confirmations using block_connected callbacks should watch
61 /// for duplicate headers and not count them towards confirmations!
62 fn block_connected(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]);
63 /// Notifies a listener that a block was disconnected.
64 /// Unlike block_connected, this *must* never be called twice for the same disconnect event.
65 fn block_disconnected(&self, header: &BlockHeader);
68 pub enum ConfirmationTarget {
74 /// A trait which should be implemented to provide feerate information on a number of time
76 /// Note that all of the functions implemented here *must* be reentrant-safe (obviously - they're
77 /// called from inside the library in response to ChainListener events, P2P events, or timer
79 pub trait FeeEstimator: Sync + Send {
80 /// Gets estimated satoshis of fee required per 1000 Weight-Units. This translates to:
81 /// * satoshis-per-byte * 250
82 /// * ceil(satoshis-per-kbyte / 4)
83 /// Must be no smaller than 253 (ie 1 satoshi-per-byte rounded up to ensure later round-downs
84 /// don't put us below 1 satoshi-per-byte).
85 fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u64;
88 /// Utility to capture some common parts of ChainWatchInterface implementors.
89 /// Keeping a local copy of this in a ChainWatchInterface implementor is likely useful.
90 pub struct ChainWatchInterfaceUtil {
92 watched: Mutex<(Vec<Script>, Vec<(Sha256dHash, u32)>, bool)>, //TODO: Something clever to optimize this
93 listeners: Mutex<Vec<Weak<ChainListener>>>,
94 reentered: AtomicUsize,
99 impl ChainWatchInterface for ChainWatchInterfaceUtil {
100 fn install_watch_script(&self, script_pub_key: &Script) {
101 let mut watched = self.watched.lock().unwrap();
102 watched.0.push(script_pub_key.clone());
103 self.reentered.fetch_add(1, Ordering::Relaxed);
106 fn install_watch_outpoint(&self, outpoint: (Sha256dHash, u32), _out_script: &Script) {
107 let mut watched = self.watched.lock().unwrap();
108 watched.1.push(outpoint);
109 self.reentered.fetch_add(1, Ordering::Relaxed);
112 fn watch_all_txn(&self) {
113 let mut watched = self.watched.lock().unwrap();
115 self.reentered.fetch_add(1, Ordering::Relaxed);
118 fn register_listener(&self, listener: Weak<ChainListener>) {
119 let mut vec = self.listeners.lock().unwrap();
123 fn get_chain_utxo(&self, genesis_hash: Sha256dHash, _unspent_tx_output_identifier: u64) -> Result<(Script, u64), ChainError> {
124 if genesis_hash != genesis_block(self.network).header.bitcoin_hash() {
125 return Err(ChainError::NotWatched);
127 Err(ChainError::NotSupported)
131 impl ChainWatchInterfaceUtil {
132 pub fn new(network: Network, logger: Arc<Logger>) -> ChainWatchInterfaceUtil {
133 ChainWatchInterfaceUtil {
135 watched: Mutex::new((Vec::new(), Vec::new(), false)),
136 listeners: Mutex::new(Vec::new()),
137 reentered: AtomicUsize::new(1),
142 /// Notify listeners that a block was connected given a full, unfiltered block.
143 /// Handles re-scanning the block and calling block_connected again if listeners register new
144 /// watch data during the callbacks for you (see ChainListener::block_connected for more info).
145 pub fn block_connected_with_filtering(&self, block: &Block, height: u32) {
146 let mut reentered = true;
148 let mut matched = Vec::new();
149 let mut matched_index = Vec::new();
151 let watched = self.watched.lock().unwrap();
152 for (index, transaction) in block.txdata.iter().enumerate() {
153 if self.does_match_tx_unguarded(transaction, &watched) {
154 matched.push(transaction);
155 matched_index.push(index as u32);
159 reentered = self.block_connected_checked(&block.header, height, matched.as_slice(), matched_index.as_slice());
163 /// Notify listeners that a block was disconnected.
164 pub fn block_disconnected(&self, header: &BlockHeader) {
165 let listeners = self.listeners.lock().unwrap().clone();
166 for listener in listeners.iter() {
167 match listener.upgrade() {
168 Some(arc) => arc.block_disconnected(header),
174 /// Notify listeners that a block was connected, given pre-filtered list of transactions in the
175 /// block which matched the filter (probably using does_match_tx).
176 /// Returns true if notified listeners registered additional watch data (implying that the
177 /// block must be re-scanned and this function called again prior to further block_connected
178 /// calls, see ChainListener::block_connected for more info).
179 pub fn block_connected_checked(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]) -> bool {
180 let last_seen = self.reentered.load(Ordering::Relaxed);
182 let listeners = self.listeners.lock().unwrap().clone();
183 for listener in listeners.iter() {
184 match listener.upgrade() {
185 Some(arc) => arc.block_connected(header, height, txn_matched, indexes_of_txn_matched),
189 return last_seen != self.reentered.load(Ordering::Relaxed);
192 /// Checks if a given transaction matches the current filter.
193 pub fn does_match_tx(&self, tx: &Transaction) -> bool {
194 let watched = self.watched.lock().unwrap();
195 self.does_match_tx_unguarded (tx, &watched)
198 fn does_match_tx_unguarded(&self, tx: &Transaction, watched: &MutexGuard<(Vec<Script>, Vec<(Sha256dHash, u32)>, bool)>) -> bool {
202 for out in tx.output.iter() {
203 for script in watched.0.iter() {
204 if script[..] == out.script_pubkey[..] {
209 for input in tx.input.iter() {
210 for outpoint in watched.1.iter() {
211 let &(outpoint_hash, outpoint_index) = outpoint;
212 if outpoint_hash == input.previous_output.txid && outpoint_index == input.previous_output.vout {