_ Git - rust-lightning/blob - src/chain/chaininterface.rs

   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 util::logger::Logger;
   6 use std::sync::{Mutex,Weak,MutexGuard,Arc};
   7 use std::sync::atomic::{AtomicUsize, Ordering};
   8
   9 /// An interface to request notification of certain scripts as they appear the
  10 /// chain.
  11 /// Note that all of the functions implemented here *must* be reentrant-safe (obviously - they're
  12 /// called from inside the library in response to ChainListener events, P2P events, or timer
  13 /// events).
  14 pub trait ChainWatchInterface: Sync + Send {
  15         /// Provides a scriptPubKey which much be watched for.
  16         fn install_watch_script(&self, script_pub_key: &Script);
  17
  18         /// Provides an outpoint which must be watched for, providing any transactions which spend the
  19         /// given outpoint.
  20         fn install_watch_outpoint(&self, outpoint: (Sha256dHash, u32), out_script: &Script);
  21
  22         /// Indicates that a listener needs to see all transactions.
  23         fn watch_all_txn(&self);
  24
  25         fn register_listener(&self, listener: Weak<ChainListener>);
  26         //TODO: unregister
  27 }
  28
  29 /// An interface to send a transaction to the Bitcoin network.
  30 pub trait BroadcasterInterface: Sync + Send {
  31         /// Sends a transaction out to (hopefully) be mined.
  32         fn broadcast_transaction(&self, tx: &Transaction);
  33 }
  34
  35 /// A trait indicating a desire to listen for events from the chain
  36 pub trait ChainListener: Sync + Send {
  37         /// Notifies a listener that a block was connected.
  38         /// Note that if a new script/transaction is watched during a block_connected call, the block
  39         /// *must* be re-scanned with the new script/transaction and block_connected should be called
  40         /// again with the same header and (at least) the new transactions.
  41         /// This also means those counting confirmations using block_connected callbacks should watch
  42         /// for duplicate headers and not count them towards confirmations!
  43         fn block_connected(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]);
  44         /// Notifies a listener that a block was disconnected.
  45         /// Unlike block_connected, this *must* never be called twice for the same disconnect event.
  46         fn block_disconnected(&self, header: &BlockHeader);
  47 }
  48
  49 pub enum ConfirmationTarget {
  50         Background,
  51         Normal,
  52         HighPriority,
  53 }
  54
  55 /// A trait which should be implemented to provide feerate information on a number of time
  56 /// horizons.
  57 /// Note that all of the functions implemented here *must* be reentrant-safe (obviously - they're
  58 /// called from inside the library in response to ChainListener events, P2P events, or timer
  59 /// events).
  60 pub trait FeeEstimator: Sync + Send {
  61         /// Gets estimated satoshis of fee required per 1000 Weight-Units. This translates to:
  62         ///  * satoshis-per-byte * 250
  63         ///  * ceil(satoshis-per-kbyte / 4)
  64         /// Must be no smaller than 253 (ie 1 satoshi-per-byte rounded up to ensure later round-downs
  65         /// don't put us below 1 satoshi-per-byte).
  66         fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u64;
  67 }
  68
  69 /// Utility to capture some common parts of ChainWatchInterface implementors.
  70 /// Keeping a local copy of this in a ChainWatchInterface implementor is likely useful.
  71 pub struct ChainWatchInterfaceUtil {
  72         watched: Mutex<(Vec<Script>, Vec<(Sha256dHash, u32)>, bool)>, //TODO: Something clever to optimize this
  73         listeners: Mutex<Vec<Weak<ChainListener>>>,
  74         reentered: AtomicUsize,
  75         logger: Arc<Logger>,
  76 }
  77
  78 /// Register listener
  79 impl ChainWatchInterface for ChainWatchInterfaceUtil {
  80         fn install_watch_script(&self, script_pub_key: &Script) {
  81                 let mut watched = self.watched.lock().unwrap();
  82                 watched.0.push(script_pub_key.clone());
  83                 self.reentered.fetch_add(1, Ordering::Relaxed);
  84         }
  85
  86         fn install_watch_outpoint(&self, outpoint: (Sha256dHash, u32), _out_script: &Script) {
  87                 let mut watched = self.watched.lock().unwrap();
  88                 watched.1.push(outpoint);
  89                 self.reentered.fetch_add(1, Ordering::Relaxed);
  90         }
  91
  92         fn watch_all_txn(&self) {
  93                 let mut watched = self.watched.lock().unwrap();
  94                 watched.2 = true;
  95                 self.reentered.fetch_add(1, Ordering::Relaxed);
  96         }
  97
  98         fn register_listener(&self, listener: Weak<ChainListener>) {
  99                 let mut vec = self.listeners.lock().unwrap();
 100                 vec.push(listener);
 101         }
 102 }
 103
 104 impl ChainWatchInterfaceUtil {
 105         pub fn new(logger: Arc<Logger>) -> ChainWatchInterfaceUtil {
 106                 ChainWatchInterfaceUtil {
 107                         watched: Mutex::new((Vec::new(), Vec::new(), false)),
 108                         listeners: Mutex::new(Vec::new()),
 109                         reentered: AtomicUsize::new(1),
 110                         logger: logger,
 111                 }
 112         }
 113
 114         /// Notify listeners that a block was connected given a full, unfiltered block.
 115         /// Handles re-scanning the block and calling block_connected again if listeners register new
 116         /// watch data during the callbacks for you (see ChainListener::block_connected for more info).
 117         pub fn block_connected_with_filtering(&self, block: &Block, height: u32) {
 118                 let mut reentered = true;
 119                 while reentered {
 120                         let mut matched = Vec::new();
 121                         let mut matched_index = Vec::new();
 122                         {
 123                                 let watched = self.watched.lock().unwrap();
 124                                 for (index, transaction) in block.txdata.iter().enumerate() {
 125                                         if self.does_match_tx_unguarded(transaction, &watched) {
 126                                                 matched.push(transaction);
 127                                                 matched_index.push(index as u32);
 128                                         }
 129                                 }
 130                         }
 131                         reentered = self.block_connected_checked(&block.header, height, matched.as_slice(), matched_index.as_slice());
 132                 }
 133         }
 134
 135         /// Notify listeners that a block was disconnected.
 136         pub fn block_disconnected(&self, header: &BlockHeader) {
 137                 let listeners = self.listeners.lock().unwrap().clone();
 138                 for listener in listeners.iter() {
 139                         match listener.upgrade() {
 140                                 Some(arc) => arc.block_disconnected(header),
 141                                 None => ()
 142                         }
 143                 }
 144         }
 145
 146         /// Notify listeners that a block was connected, given pre-filtered list of transactions in the
 147         /// block which matched the filter (probably using does_match_tx).
 148         /// Returns true if notified listeners registered additional watch data (implying that the
 149         /// block must be re-scanned and this function called again prior to further block_connected
 150         /// calls, see ChainListener::block_connected for more info).
 151         pub fn block_connected_checked(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]) -> bool {
 152                 let last_seen = self.reentered.load(Ordering::Relaxed);
 153
 154                 let listeners = self.listeners.lock().unwrap().clone();
 155                 for listener in listeners.iter() {
 156                         match listener.upgrade() {
 157                                 Some(arc) => arc.block_connected(header, height, txn_matched, indexes_of_txn_matched),
 158                                 None => ()
 159                         }
 160                 }
 161                 return last_seen != self.reentered.load(Ordering::Relaxed);
 162         }
 163
 164         /// Checks if a given transaction matches the current filter.
 165         pub fn does_match_tx(&self, tx: &Transaction) -> bool {
 166                 let watched = self.watched.lock().unwrap();
 167                 self.does_match_tx_unguarded (tx, &watched)
 168         }
 169
 170         fn does_match_tx_unguarded(&self, tx: &Transaction, watched: &MutexGuard<(Vec<Script>, Vec<(Sha256dHash, u32)>, bool)>) -> bool {
 171                 if watched.2 {
 172                         return true;
 173                 }
 174                 for out in tx.output.iter() {
 175                         for script in watched.0.iter() {
 176                                 if script[..] == out.script_pubkey[..] {
 177                                         return true;
 178                                 }
 179                         }
 180                 }
 181                 for input in tx.input.iter() {
 182                         for outpoint in watched.1.iter() {
 183                                 let &(outpoint_hash, outpoint_index) = outpoint;
 184                                 if outpoint_hash == input.previous_output.txid && outpoint_index == input.previous_output.vout {
 185                                         return true;
 186                                 }
 187                         }
 188                 }
 189                 false
 190         }
 191 }