Define a separate trait akin to chain::Listen for notifying when
transactions have been confirmed on chain or unconfirmed during a chain
reorganization. Whereas chain::Listen is used for block-oriented chain
sources, chain::Confirm is used for chain sources supplying data for
activity related to transactions and outputs registered via
chain::Filter.
When registering a watched transaction output, any in-block descendant
transactions spending the output must be supplied. Give the block hash
when registering such outputs such that this is possible. Otherwise,
spends from other blocks may be returned inadvertently.
Electrum clients primarily operate by subscribing to notifications of
transactions by script pubkeys. Therefore, they will send filtered
transaction data without including dependent transactions. Outputs for
such transactions must be explicitly registered with these clients.
Therefore, upon block_connected, provide a mechanism for an Electrum-
backed chain::Filter to return new transaction data to scan.
Add a utility for syncing a set of chain listeners to a common chain
tip. Required to use before creating an SpvClient when the chain
listener used with the client is actually a set of listeners each of
which may have had left off at a different block. This would occur when
the listeners had been persisted individually at different frequencies
(e.g., a ChainMonitor's individual ChannelMonitors).
The `ChannelKeys` object really isn't about keys at all anymore,
its all about signing. At the same time, we rename the type aliases
used in traits from both `ChanKeySigner` and `Keys` to just
`Signer` (or, in contexts where Channel isnt clear, `ChanSigner`).
Given the chain::Watch interface is defined in terms of ChannelMonitor
and ChannelMonitorUpdateErr, move channelmonitor.rs from the ln module
to the chain module.
Outputs to watch are tracked by ChannelMonitor as of
73dce207dd. Instead of determining new
outputs to watch independently using ChainWatchedUtil, do so by
comparing against outputs already tracked. Thus, ChainWatchedUtil and
WatchEvent are no longer needed.
WatchEventProvider served as a means for replacing ChainWatchInterface.
However, it requires users to explicitly fetch WatchEvents, even if not
interested in them. Replace WatchEventProvider by chain::Filter, which
is an optional member of ChainMonitor. If set, interesting transactions
and output spends are registered such that blocks containing them can be
retrieved from a chain source in an efficient manner.
This is useful when the chain source is not a full node. For Electrum,
it allows for pre-filtered blocks. For BIP157/158, it serves as a means
to match against compact filters.
Rename ManyChannelMonitor to chain::Watch and move to chain/mod.rs,
where chain-related interfaces live. Update the documentation for
clarity and to conform to rustdoc formatting.
ChainWatchInterface was intended as an interface for watching rather
than accessing the chain. Remove get_chain_utxo and add chain::Access
trait for this behavior. Wrap it with an Option in NetGraphMsgHandler in
order to simplify the error interface.
SimpleManyChannelMonitor is parameterized by ChainWatchInterface to
signal what transactions and outputs to watch for on chain. The
interface has grown to cover chain access (via get_chain_utxo) and block
block filtering (via filter_block and reentered), which has added
complexity for implementations and user (see ChainWatchInterfaceUtil).
Pull the watch functionality out as a first step to eliminating
ChainWatchInterface entirely.
This changes the LICENSE file and adds license headers to most files
to relicense under dual Apache-2.0 and MIT. This is helpful in that
we retain the patent grant issued under Apache-2.0-licensed work,
avoiding some sticky patent issues, while still allowing users who
are more comfortable with the simpler MIT license to use that.
See https://github.com/rust-bitcoin/rust-lightning/issues/659 for
relicensing statements from code authors.
