+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
//! Structs and traits which allow other parts of rust-lightning to interact with the blockchain.
+use bitcoin::blockdata::script::Script;
+use bitcoin::blockdata::transaction::TxOut;
+use bitcoin::hash_types::{BlockHash, Txid};
+
+use chain::keysinterface::ChannelKeys;
+use chain::transaction::OutPoint;
+use ln::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateErr, MonitorEvent};
+
pub mod chaininterface;
pub mod transaction;
pub mod keysinterface;
+
+/// The `Access` trait defines behavior for accessing chain data and state, such as blocks and
+/// UTXOs.
+pub trait Access: Send + Sync {
+ /// Returns the transaction output of a funding transaction encoded by [`short_channel_id`].
+ /// Returns an error if `genesis_hash` is for a different chain or if such a transaction output
+ /// is unknown.
+ ///
+ /// [`short_channel_id`]: https://github.com/lightningnetwork/lightning-rfc/blob/master/07-routing-gossip.md#definition-of-short_channel_id
+ fn get_utxo(&self, genesis_hash: &BlockHash, short_channel_id: u64) -> Result<TxOut, AccessError>;
+}
+
+/// 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 `Watch` trait defines behavior for watching on-chain activity pertaining to channels as
+/// blocks are connected and disconnected.
+///
+/// Each channel is associated with a [`ChannelMonitor`]. Implementations of this trait are
+/// responsible for maintaining a set of monitors such that they can be updated accordingly as
+/// channel state changes and HTLCs are resolved. See method documentation for specific
+/// requirements.
+///
+/// Implementations **must** ensure that updates are successfully applied and persisted upon method
+/// completion. If an update fails with a [`PermanentFailure`], then it must immediately shut down
+/// without taking any further action such as persisting the current state.
+///
+/// If an implementation maintains multiple instances of a channel's monitor (e.g., by storing
+/// backup copies), then it must ensure that updates are applied across all instances. Otherwise, it
+/// could result in a revoked transaction being broadcast, allowing the counterparty to claim all
+/// 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;
+
+ /// 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.
+ ///
+ /// [`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>;
+
+ /// 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
+ 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
+ /// events.
+ fn release_pending_monitor_events(&self) -> Vec<MonitorEvent>;
+}
+
+/// An interface for providing [`WatchEvent`]s.
+///
+/// [`WatchEvent`]: enum.WatchEvent.html
+pub trait WatchEventProvider {
+ /// Releases events produced since the last call. Subsequent calls must only return new events.
+ fn release_pending_watch_events(&self) -> Vec<WatchEvent>;
+}
+
+/// An event indicating on-chain activity to watch for pertaining to a channel.
+pub enum WatchEvent {
+ /// Watch for a transaction with `txid` and having an output with `script_pubkey` as a spending
+ /// condition.
+ WatchTransaction {
+ /// Identifier of the transaction.
+ txid: Txid,
+
+ /// Spending condition for an output of the transaction.
+ script_pubkey: Script,
+ },
+ /// Watch for spends of a transaction output identified by `outpoint` having `script_pubkey` as
+ /// the spending condition.
+ WatchOutput {
+ /// Identifier for the output.
+ outpoint: OutPoint,
+
+ /// Spending condition for the output.
+ script_pubkey: Script,
+ }
+}
projects / rust-lightning / blobdiff