X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;ds=sidebyside;f=lightning%2Fsrc%2Fchain%2Fchaininterface.rs;h=f65ae3611f623af549da1f75a556463363f8e0ae;hb=367834ca9039eb64d6f85b6bd4432c735e776b81;hp=21a2d578d1497496ffaf7092606de44de88078ed;hpb=82b608d5f3b61cb28ddedd946ae1dcf82a69d625;p=rust-lightning diff --git a/lightning/src/chain/chaininterface.rs b/lightning/src/chain/chaininterface.rs index 21a2d578..f65ae361 100644 --- a/lightning/src/chain/chaininterface.rs +++ b/lightning/src/chain/chaininterface.rs @@ -13,63 +13,12 @@ //! 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::block::BlockHeader; use bitcoin::blockdata::transaction::Transaction; use bitcoin::blockdata::script::Script; -use bitcoin::blockdata::constants::genesis_block; -use bitcoin::network::constants::Network; -use bitcoin::hash_types::{Txid, BlockHash}; +use bitcoin::hash_types::Txid; -use std::sync::{Mutex, MutexGuard, Arc}; -use std::sync::atomic::{AtomicUsize, Ordering}; use std::collections::HashSet; -use std::ops::Deref; -use std::marker::PhantomData; -use std::ptr; - -/// Used to give chain error details upstream -#[derive(Clone)] -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 txid/random-scriptPubKey-in-the-tx which much be watched for. - fn install_watch_tx(&self, txid: &Txid, script_pub_key: &Script); - - /// Provides an outpoint which must be watched for, providing any transactions which spend the - /// given outpoint. - fn install_watch_outpoint(&self, outpoint: (Txid, u32), out_script: &Script); - - /// Indicates that a listener needs to see all transactions. - fn watch_all_txn(&self); - - /// 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: BlockHash, unspent_tx_output_identifier: u64) -> Result<(Script, u64), ChainError>; - - /// Gets the list of transaction indices within a given block that the ChainWatchInterface is - /// watching for. - fn filter_block(&self, header: &BlockHeader, txdata: &[(usize, &Transaction)]) -> Vec; - - /// Returns a usize that changes when the ChainWatchInterface's watched data is modified. - /// Users of `filter_block` should pre-save a copy of `reentered`'s return value and use it to - /// determine whether they need to re-filter a given block. - fn reentered(&self) -> usize; -} /// An interface to send a transaction to the Bitcoin network. pub trait BroadcasterInterface: Sync + Send { @@ -208,244 +157,3 @@ impl ChainWatchedUtil { false } } - -/// BlockNotifierArc is useful when you need a BlockNotifier that points to ChainListeners with -/// static lifetimes, e.g. when you're using lightning-net-tokio (since tokio::spawn requires -/// parameters with static lifetimes). Other times you can afford a reference, which is more -/// efficient, in which case BlockNotifierRef is a more appropriate type. Defining these type -/// aliases prevents issues such as overly long function definitions. -/// -/// (C-not exported) as we let clients handle any reference counting they need to do -pub type BlockNotifierArc = Arc>>; - -/// BlockNotifierRef is useful when you want a BlockNotifier that points to ChainListeners -/// with nonstatic lifetimes. This is useful for when static lifetimes are not needed. Nonstatic -/// lifetimes are more efficient but less flexible, and should be used by default unless static -/// lifetimes are required, e.g. when you're using lightning-net-tokio (since tokio::spawn -/// requires parameters with static lifetimes), in which case BlockNotifierArc is a more -/// appropriate type. Defining these type aliases for common usages prevents issues such as -/// overly long function definitions. -pub type BlockNotifierRef<'a> = BlockNotifier<'a, &'a ChainListener>; - -/// Utility for notifying listeners when blocks are connected or disconnected. -/// -/// Rather than using a plain BlockNotifier, it is preferable to use either a BlockNotifierArc -/// or a BlockNotifierRef for conciseness. See their documentation for more details, but essentially -/// you should default to using a BlockNotifierRef, and use a BlockNotifierArc instead when you -/// require ChainListeners with static lifetimes, such as when you're using lightning-net-tokio. -pub struct BlockNotifier<'a, CL: Deref + 'a> - where CL::Target: ChainListener + 'a { - listeners: Mutex>, - phantom: PhantomData<&'a ()>, -} - -impl<'a, CL: Deref + 'a> BlockNotifier<'a, CL> - where CL::Target: ChainListener + 'a { - /// Constructs a new BlockNotifier without any listeners. - pub fn new() -> BlockNotifier<'a, CL> { - BlockNotifier { - listeners: Mutex::new(Vec::new()), - phantom: PhantomData, - } - } - - /// Register the given listener to receive events. - pub fn register_listener(&self, listener: CL) { - let mut vec = self.listeners.lock().unwrap(); - vec.push(listener); - } - /// Unregister the given listener to no longer - /// receive events. - /// - /// If the same listener is registered multiple times, unregistering - /// will remove ALL occurrences of that listener. Comparison is done using - /// the pointer returned by the Deref trait implementation. - /// - /// (C-not exported) because the equality check would always fail - pub fn unregister_listener(&self, listener: CL) { - let mut vec = self.listeners.lock().unwrap(); - // item is a ref to an abstract thing that dereferences to a ChainListener, - // so dereference it twice to get the ChainListener itself - vec.retain(|item | !ptr::eq(&(**item), &(*listener))); - } - - /// Notify listeners that a block was connected. - pub fn block_connected(&self, block: &Block, height: u32) { - let txdata: Vec<_> = block.txdata.iter().enumerate().collect(); - let listeners = self.listeners.lock().unwrap(); - for listener in listeners.iter() { - listener.block_connected(&block.header, &txdata, height); - } - } - - /// Notify listeners that a block was disconnected. - pub fn block_disconnected(&self, header: &BlockHeader, disconnected_height: u32) { - let listeners = self.listeners.lock().unwrap(); - for listener in listeners.iter() { - listener.block_disconnected(&header, disconnected_height); - } - } -} - -/// 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 { - network: Network, - watched: Mutex, - reentered: AtomicUsize, -} - -// We only expose PartialEq in test since its somewhat unclear exactly what it should do and we're -// only comparing a subset of fields (essentially just checking that the set of things we're -// watching is the same). -#[cfg(test)] -impl PartialEq for ChainWatchInterfaceUtil { - fn eq(&self, o: &Self) -> bool { - self.network == o.network && - *self.watched.lock().unwrap() == *o.watched.lock().unwrap() - } -} - -/// Register listener -impl ChainWatchInterface for ChainWatchInterfaceUtil { - fn install_watch_tx(&self, txid: &Txid, script_pub_key: &Script) { - let mut watched = self.watched.lock().unwrap(); - if watched.register_tx(txid, script_pub_key) { - self.reentered.fetch_add(1, Ordering::Relaxed); - } - } - - fn install_watch_outpoint(&self, outpoint: (Txid, u32), out_script: &Script) { - let mut watched = self.watched.lock().unwrap(); - 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(); - if watched.watch_all() { - self.reentered.fetch_add(1, Ordering::Relaxed); - } - } - - fn get_chain_utxo(&self, genesis_hash: BlockHash, _unspent_tx_output_identifier: u64) -> Result<(Script, u64), ChainError> { - if genesis_hash != genesis_block(self.network).header.block_hash() { - return Err(ChainError::NotWatched); - } - Err(ChainError::NotSupported) - } - - fn filter_block(&self, _header: &BlockHeader, txdata: &[(usize, &Transaction)]) -> Vec { - let mut matched_index = Vec::new(); - let mut matched_txids = HashSet::new(); - { - let watched = self.watched.lock().unwrap(); - for (index, transaction) in txdata.iter().enumerate() { - // A tx matches the filter if it either matches the filter directly (via - // does_match_tx_unguarded) or if it is a descendant of another matched - // transaction within the same block, which we check for in the loop. - let mut matched = self.does_match_tx_unguarded(transaction.1, &watched); - for input in transaction.1.input.iter() { - if matched || matched_txids.contains(&input.previous_output.txid) { - matched = true; - break; - } - } - if matched { - matched_txids.insert(transaction.1.txid()); - matched_index.push(index); - } - } - } - matched_index - } - - fn reentered(&self) -> usize { - self.reentered.load(Ordering::Relaxed) - } -} - -impl ChainWatchInterfaceUtil { - /// Creates a new ChainWatchInterfaceUtil for the given network - pub fn new(network: Network) -> ChainWatchInterfaceUtil { - ChainWatchInterfaceUtil { - network, - watched: Mutex::new(ChainWatchedUtil::new()), - reentered: AtomicUsize::new(1), - } - } - - /// Checks if a given transaction matches the current filter. - pub fn does_match_tx(&self, tx: &Transaction) -> bool { - let watched = self.watched.lock().unwrap(); - self.does_match_tx_unguarded (tx, &watched) - } - - fn does_match_tx_unguarded(&self, tx: &Transaction, watched: &MutexGuard) -> bool { - watched.does_match_tx(tx) - } -} - -#[cfg(test)] -mod tests { - use bitcoin::blockdata::block::BlockHeader; - use bitcoin::blockdata::transaction::Transaction; - use super::{BlockNotifier, ChainListener}; - use std::ptr; - - struct TestChainListener(u8); - - impl ChainListener for TestChainListener { - fn block_connected(&self, _header: &BlockHeader, _txdata: &[(usize, &Transaction)], _height: u32) {} - fn block_disconnected(&self, _header: &BlockHeader, _disconnected_height: u32) {} - } - - #[test] - fn register_listener_test() { - let block_notifier = BlockNotifier::new(); - assert_eq!(block_notifier.listeners.lock().unwrap().len(), 0); - let listener = &TestChainListener(0); - block_notifier.register_listener(listener as &ChainListener); - let vec = block_notifier.listeners.lock().unwrap(); - assert_eq!(vec.len(), 1); - let item = vec.first().unwrap(); - assert!(ptr::eq(&(**item), listener)); - } - - #[test] - fn unregister_single_listener_test() { - let block_notifier = BlockNotifier::new(); - let listener1 = &TestChainListener(1); - let listener2 = &TestChainListener(2); - block_notifier.register_listener(listener1 as &ChainListener); - block_notifier.register_listener(listener2 as &ChainListener); - let vec = block_notifier.listeners.lock().unwrap(); - assert_eq!(vec.len(), 2); - drop(vec); - block_notifier.unregister_listener(listener1); - let vec = block_notifier.listeners.lock().unwrap(); - assert_eq!(vec.len(), 1); - let item = vec.first().unwrap(); - assert!(ptr::eq(&(**item), listener2)); - } - - #[test] - fn unregister_multiple_of_the_same_listeners_test() { - let block_notifier = BlockNotifier::new(); - let listener1 = &TestChainListener(1); - let listener2 = &TestChainListener(2); - block_notifier.register_listener(listener1 as &ChainListener); - block_notifier.register_listener(listener1 as &ChainListener); - block_notifier.register_listener(listener2 as &ChainListener); - let vec = block_notifier.listeners.lock().unwrap(); - assert_eq!(vec.len(), 3); - drop(vec); - block_notifier.unregister_listener(listener1); - let vec = block_notifier.listeners.lock().unwrap(); - assert_eq!(vec.len(), 1); - let item = vec.first().unwrap(); - assert!(ptr::eq(&(**item), listener2)); - } -}