1 use bitcoin::blockdata::block::{Block, BlockHeader};
2 use bitcoin::blockdata::transaction::Transaction;
3 use bitcoin::blockdata::script::Script;
4 use bitcoin::util::hash::Sha256dHash;
5 use std::sync::{Mutex,Weak,MutexGuard};
6 use std::sync::atomic::{AtomicUsize, Ordering};
8 /// An interface to request notification of certain scripts as they appear the
10 /// Note that all of the functions implemented here *must* be reentrant-safe (obviously - they're
11 /// called from inside the library in response to ChainListener events, P2P events, or timer
13 pub trait ChainWatchInterface: Sync + Send {
14 /// Provides a scriptPubKey which much be watched for.
15 fn install_watch_script(&self, script_pub_key: Script);
17 /// Provides an outpoint which must be watched for, providing any transactions which spend the
19 fn install_watch_outpoint(&self, outpoint: (Sha256dHash, u32));
21 /// Indicates that a listener needs to see all transactions.
22 fn watch_all_txn(&self);
24 fn register_listener(&self, listener: Weak<ChainListener>);
28 /// An interface to send a transaction to connected Bitcoin peers.
29 /// This is for final settlement. An error might indicate that no peers can be reached or
30 /// that peers rejected the transaction.
31 pub trait BroadcasterInterface: Sync + Send {
32 /// Sends a transaction out to (hopefully) be mined
33 fn broadcast_transaction(&self, tx: &Transaction);
36 /// A trait indicating a desire to listen for events from the chain
37 pub trait ChainListener: Sync + Send {
38 /// Notifies a listener that a block was connected.
39 /// Note that if a new script/transaction is watched during a block_connected call, the block
40 /// *must* be re-scanned with the new script/transaction and block_connected should be called
41 /// again with the same header and (at least) the new transactions.
42 /// This also means those counting confirmations using block_connected callbacks should watch
43 /// for duplicate headers and not count them towards confirmations!
44 fn block_connected(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]);
45 /// Notifies a listener that a block was disconnected.
46 /// Unlike block_connected, this *must* never be called twice for the same disconnect event.
47 fn block_disconnected(&self, header: &BlockHeader);
50 pub enum ConfirmationTarget {
56 /// A trait which should be implemented to provide feerate information on a number of time
58 /// Note that all of the functions implemented here *must* be reentrant-safe (obviously - they're
59 /// called from inside the library in response to ChainListener events, P2P events, or timer
61 pub trait FeeEstimator: Sync + Send {
62 fn get_est_sat_per_vbyte(&self, confirmation_target: ConfirmationTarget) -> u64;
65 /// Utility to capture some common parts of ChainWatchInterface implementors.
66 /// Keeping a local copy of this in a ChainWatchInterface implementor is likely useful.
67 pub struct ChainWatchInterfaceUtil {
68 watched: Mutex<(Vec<Script>, Vec<(Sha256dHash, u32)>, bool)>, //TODO: Something clever to optimize this
69 listeners: Mutex<Vec<Weak<ChainListener>>>,
70 reentered: AtomicUsize
74 impl ChainWatchInterface for ChainWatchInterfaceUtil {
75 fn install_watch_script(&self, script_pub_key: Script) {
76 let mut watched = self.watched.lock().unwrap();
77 watched.0.push(Script::from(script_pub_key));
78 self.reentered.fetch_add(1, Ordering::Relaxed);
81 fn install_watch_outpoint(&self, outpoint: (Sha256dHash, u32)) {
82 let mut watched = self.watched.lock().unwrap();
83 watched.1.push(outpoint);
84 self.reentered.fetch_add(1, Ordering::Relaxed);
87 fn watch_all_txn(&self) {
88 let mut watched = self.watched.lock().unwrap();
90 self.reentered.fetch_add(1, Ordering::Relaxed);
93 fn register_listener(&self, listener: Weak<ChainListener>) {
94 let mut vec = self.listeners.lock().unwrap();
99 impl ChainWatchInterfaceUtil {
100 pub fn new() -> ChainWatchInterfaceUtil {
101 ChainWatchInterfaceUtil {
102 watched: Mutex::new((Vec::new(), Vec::new(), false)),
103 listeners: Mutex::new(Vec::new()),
104 reentered: AtomicUsize::new(1)
108 /// notify listener that a block was connected
109 /// notification will repeat if notified listener register new listeners
110 pub fn block_connected_with_filtering(&self, block: &Block, height: u32) {
111 let mut reentered = true;
113 let mut matched = Vec::new();
114 let mut matched_index = Vec::new();
116 let watched = self.watched.lock().unwrap();
117 for (index, transaction) in block.txdata.iter().enumerate() {
118 if self.does_match_tx_unguarded(transaction, &watched) {
119 matched.push(transaction);
120 matched_index.push(index as u32);
124 reentered = self.block_connected_checked(&block.header, height, matched.as_slice(), matched_index.as_slice());
128 /// notify listener that a block was disconnected
129 pub fn block_disconnected(&self, header: &BlockHeader) {
130 let listeners = self.listeners.lock().unwrap().clone();
131 for listener in listeners.iter() {
132 match listener.upgrade() {
133 Some(arc) => arc.block_disconnected(header),
139 /// call listeners for connected blocks if they are still around.
140 /// returns true if notified listeners registered additional listener
141 pub fn block_connected_checked(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]) -> bool {
142 let last_seen = self.reentered.load(Ordering::Relaxed);
144 let listeners = self.listeners.lock().unwrap().clone();
145 for listener in listeners.iter() {
146 match listener.upgrade() {
147 Some(arc) => arc.block_connected(header, height, txn_matched, indexes_of_txn_matched),
151 return last_seen != self.reentered.load(Ordering::Relaxed);
154 /// Checks if a given transaction matches the current filter
155 pub fn does_match_tx(&self, tx: &Transaction) -> bool {
156 let watched = self.watched.lock().unwrap();
157 self.does_match_tx_unguarded (tx, &watched)
160 fn does_match_tx_unguarded (&self, tx: &Transaction, watched: &MutexGuard<(Vec<Script>, Vec<(Sha256dHash, u32)>, bool)>) -> bool {
164 for out in tx.output.iter() {
165 for script in watched.0.iter() {
166 if script[..] == out.script_pubkey[..] {
171 for input in tx.input.iter() {
172 for outpoint in watched.1.iter() {
173 let &(outpoint_hash, outpoint_index) = outpoint;
174 if outpoint_hash == input.prev_hash && outpoint_index == input.prev_index {