Utility for syncing a set of chain listeners
[rust-lightning] / lightning / src / chain / mod.rs
index 7721408c4390e035cb9836a50c9e3f277762b879..c1fceec8c47171969397558db0ce62d11faf93ed 100644 (file)
@@ -9,18 +9,33 @@
 
 //! Structs and traits which allow other parts of rust-lightning to interact with the blockchain.
 
+use bitcoin::blockdata::block::{Block, BlockHeader};
 use bitcoin::blockdata::script::Script;
 use bitcoin::blockdata::transaction::TxOut;
 use bitcoin::hash_types::{BlockHash, Txid};
 
-use chain::keysinterface::ChannelKeys;
+use chain::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateErr, MonitorEvent};
+use chain::keysinterface::Sign;
 use chain::transaction::OutPoint;
-use ln::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateErr, MonitorEvent};
 
 pub mod chaininterface;
+pub mod chainmonitor;
+pub mod channelmonitor;
 pub mod transaction;
 pub mod keysinterface;
 
+/// An error when accessing the chain via [`Access`].
+///
+/// [`Access`]: trait.Access.html
+#[derive(Clone)]
+pub enum AccessError {
+       /// The requested chain is unknown.
+       UnknownChain,
+
+       /// The requested transaction doesn't exist or hasn't confirmed.
+       UnknownTx,
+}
+
 /// The `Access` trait defines behavior for accessing chain data and state, such as blocks and
 /// UTXOs.
 pub trait Access: Send + Sync {
@@ -32,16 +47,16 @@ pub trait Access: Send + Sync {
        fn get_utxo(&self, genesis_hash: &BlockHash, short_channel_id: u64) -> Result<TxOut, AccessError>;
 }
 
-/// An error when accessing the chain via [`Access`].
+/// The `Listen` trait is used to be notified of when blocks have been connected or disconnected
+/// from the chain.
 ///
-/// [`Access`]: trait.Access.html
-#[derive(Clone)]
-pub enum AccessError {
-       /// The requested chain is unknown.
-       UnknownChain,
+/// Useful when needing to replay chain data upon startup or as new chain events occur.
+pub trait Listen {
+       /// Notifies the listener that a block was added at the given height.
+       fn block_connected(&self, block: &Block, height: u32);
 
-       /// The requested transaction doesn't exist or hasn't confirmed.
-       UnknownTx,
+       /// Notifies the listener that a block was removed at the given height.
+       fn block_disconnected(&self, header: &BlockHeader, height: u32);
 }
 
 /// The `Watch` trait defines behavior for watching on-chain activity pertaining to channels as
@@ -62,32 +77,28 @@ pub enum AccessError {
 /// funds in the channel. See [`ChannelMonitorUpdateErr`] for more details about how to handle
 /// multiple instances.
 ///
-/// [`ChannelMonitor`]: ../ln/channelmonitor/struct.ChannelMonitor.html
-/// [`ChannelMonitorUpdateErr`]: ../ln/channelmonitor/enum.ChannelMonitorUpdateErr.html
-/// [`PermanentFailure`]: ../ln/channelmonitor/enum.ChannelMonitorUpdateErr.html#variant.PermanentFailure
-pub trait Watch: Send + Sync {
-       /// Keys needed by monitors for creating and signing transactions.
-       type Keys: ChannelKeys;
-
+/// [`ChannelMonitor`]: channelmonitor/struct.ChannelMonitor.html
+/// [`ChannelMonitorUpdateErr`]: channelmonitor/enum.ChannelMonitorUpdateErr.html
+/// [`PermanentFailure`]: channelmonitor/enum.ChannelMonitorUpdateErr.html#variant.PermanentFailure
+pub trait Watch<ChannelSigner: Sign>: Send + Sync {
        /// Watches a channel identified by `funding_txo` using `monitor`.
        ///
        /// Implementations are responsible for watching the chain for the funding transaction along
-       /// with spends of its output and any outputs returned by [`get_outputs_to_watch`]. In practice,
-       /// this means calling [`block_connected`] and [`block_disconnected`] on the monitor and
-       /// including all such transactions that meet this criteria.
+       /// with any spends of outputs returned by [`get_outputs_to_watch`]. In practice, this means
+       /// calling [`block_connected`] and [`block_disconnected`] on the monitor.
        ///
-       /// [`get_outputs_to_watch`]: ../ln/channelmonitor/struct.ChannelMonitor.html#method.get_outputs_to_watch
-       /// [`block_connected`]: ../ln/channelmonitor/struct.ChannelMonitor.html#method.block_connected
-       /// [`block_disconnected`]: ../ln/channelmonitor/struct.ChannelMonitor.html#method.block_disconnected
-       fn watch_channel(&self, funding_txo: OutPoint, monitor: ChannelMonitor<Self::Keys>) -> Result<(), ChannelMonitorUpdateErr>;
+       /// [`get_outputs_to_watch`]: channelmonitor/struct.ChannelMonitor.html#method.get_outputs_to_watch
+       /// [`block_connected`]: channelmonitor/struct.ChannelMonitor.html#method.block_connected
+       /// [`block_disconnected`]: channelmonitor/struct.ChannelMonitor.html#method.block_disconnected
+       fn watch_channel(&self, funding_txo: OutPoint, monitor: ChannelMonitor<ChannelSigner>) -> Result<(), ChannelMonitorUpdateErr>;
 
        /// Updates a channel identified by `funding_txo` by applying `update` to its monitor.
        ///
        /// Implementations must call [`update_monitor`] with the given update. See
        /// [`ChannelMonitorUpdateErr`] for invariants around returning an error.
        ///
-       /// [`update_monitor`]: ../ln/channelmonitor/struct.ChannelMonitor.html#method.update_monitor
-       /// [`ChannelMonitorUpdateErr`]: ../ln/channelmonitor/enum.ChannelMonitorUpdateErr.html
+       /// [`update_monitor`]: channelmonitor/struct.ChannelMonitor.html#method.update_monitor
+       /// [`ChannelMonitorUpdateErr`]: channelmonitor/enum.ChannelMonitorUpdateErr.html
        fn update_channel(&self, funding_txo: OutPoint, update: ChannelMonitorUpdate) -> Result<(), ChannelMonitorUpdateErr>;
 
        /// Returns any monitor events since the last call. Subsequent calls must only return new
@@ -113,15 +124,41 @@ pub trait Watch: Send + Sync {
 /// invocation that has called the `Filter` must return [`TemporaryFailure`].
 ///
 /// [`Watch`]: trait.Watch.html
-/// [`TemporaryFailure`]: ../ln/channelmonitor/enum.ChannelMonitorUpdateErr.html#variant.TemporaryFailure
+/// [`TemporaryFailure`]: channelmonitor/enum.ChannelMonitorUpdateErr.html#variant.TemporaryFailure
 /// [BIP 157]: https://github.com/bitcoin/bips/blob/master/bip-0157.mediawiki
 /// [BIP 158]: https://github.com/bitcoin/bips/blob/master/bip-0158.mediawiki
 pub trait Filter: Send + Sync {
        /// Registers interest in a transaction with `txid` and having an output with `script_pubkey` as
        /// a spending condition.
-       fn register_tx(&self, txid: Txid, script_pubkey: Script);
+       fn register_tx(&self, txid: &Txid, script_pubkey: &Script);
 
        /// Registers interest in spends of a transaction output identified by `outpoint` having
        /// `script_pubkey` as the spending condition.
-       fn register_output(&self, outpoint: OutPoint, script_pubkey: Script);
+       fn register_output(&self, outpoint: &OutPoint, script_pubkey: &Script);
+}
+
+impl<T: Listen> Listen for std::ops::Deref<Target = T> {
+       fn block_connected(&self, block: &Block, height: u32) {
+               (**self).block_connected(block, height);
+       }
+
+       fn block_disconnected(&self, header: &BlockHeader, height: u32) {
+               (**self).block_disconnected(header, height);
+       }
+}
+
+impl<T: std::ops::Deref, U: std::ops::Deref> Listen for (T, U)
+where
+       T::Target: Listen,
+       U::Target: Listen,
+{
+       fn block_connected(&self, block: &Block, height: u32) {
+               self.0.block_connected(block, height);
+               self.1.block_connected(block, height);
+       }
+
+       fn block_disconnected(&self, header: &BlockHeader, height: u32) {
+               self.0.block_disconnected(header, height);
+               self.1.block_disconnected(header, height);
+       }
 }