bdk/crates/chain/src/spk_client.rs
LLFourn 53fa35096f
refactor(electrum)!: put the tx cache in electrum
Previously there was a tx cache that you passed in as part of the sync
request. This seems bad and the example show'd that you should copy all
your transactions from the transaction graph into the sync request every
time you sync'd. If you forgot to do this then you would always download everything.

Instead just do a plain old simple cache inside the electrum client.
This way at least you only download transactions once. You can
pre-populate the cache with a method also and I did this in the examples.
2024-06-04 12:23:01 +08:00

388 lines
13 KiB
Rust

//! Helper types for spk-based blockchain clients.
use crate::{
collections::BTreeMap, local_chain::CheckPoint, ConfirmationTimeHeightAnchor, TxGraph,
};
use alloc::{boxed::Box, vec::Vec};
use bitcoin::{OutPoint, Script, ScriptBuf, Txid};
use core::{fmt::Debug, marker::PhantomData, ops::RangeBounds};
/// Data required to perform a spk-based blockchain client sync.
///
/// A client sync fetches relevant chain data for a known list of scripts, transaction ids and
/// outpoints. The sync process also updates the chain from the given [`CheckPoint`].
pub struct SyncRequest {
/// A checkpoint for the current chain [`LocalChain::tip`].
/// The sync process will return a new chain update that extends this tip.
///
/// [`LocalChain::tip`]: crate::local_chain::LocalChain::tip
pub chain_tip: CheckPoint,
/// Transactions that spend from or to these indexed script pubkeys.
pub spks: Box<dyn ExactSizeIterator<Item = ScriptBuf> + Send>,
/// Transactions with these txids.
pub txids: Box<dyn ExactSizeIterator<Item = Txid> + Send>,
/// Transactions with these outpoints or spent from these outpoints.
pub outpoints: Box<dyn ExactSizeIterator<Item = OutPoint> + Send>,
}
impl SyncRequest {
/// Construct a new [`SyncRequest`] from a given `cp` tip.
pub fn from_chain_tip(cp: CheckPoint) -> Self {
Self {
chain_tip: cp,
spks: Box::new(core::iter::empty()),
txids: Box::new(core::iter::empty()),
outpoints: Box::new(core::iter::empty()),
}
}
/// Set the [`Script`]s that will be synced against.
///
/// This consumes the [`SyncRequest`] and returns the updated one.
#[must_use]
pub fn set_spks(
mut self,
spks: impl IntoIterator<IntoIter = impl ExactSizeIterator<Item = ScriptBuf> + Send + 'static>,
) -> Self {
self.spks = Box::new(spks.into_iter());
self
}
/// Set the [`Txid`]s that will be synced against.
///
/// This consumes the [`SyncRequest`] and returns the updated one.
#[must_use]
pub fn set_txids(
mut self,
txids: impl IntoIterator<IntoIter = impl ExactSizeIterator<Item = Txid> + Send + 'static>,
) -> Self {
self.txids = Box::new(txids.into_iter());
self
}
/// Set the [`OutPoint`]s that will be synced against.
///
/// This consumes the [`SyncRequest`] and returns the updated one.
#[must_use]
pub fn set_outpoints(
mut self,
outpoints: impl IntoIterator<
IntoIter = impl ExactSizeIterator<Item = OutPoint> + Send + 'static,
>,
) -> Self {
self.outpoints = Box::new(outpoints.into_iter());
self
}
/// Chain on additional [`Script`]s that will be synced against.
///
/// This consumes the [`SyncRequest`] and returns the updated one.
#[must_use]
pub fn chain_spks(
mut self,
spks: impl IntoIterator<
IntoIter = impl ExactSizeIterator<Item = ScriptBuf> + Send + 'static,
Item = ScriptBuf,
>,
) -> Self {
self.spks = Box::new(ExactSizeChain::new(self.spks, spks.into_iter()));
self
}
/// Chain on additional [`Txid`]s that will be synced against.
///
/// This consumes the [`SyncRequest`] and returns the updated one.
#[must_use]
pub fn chain_txids(
mut self,
txids: impl IntoIterator<
IntoIter = impl ExactSizeIterator<Item = Txid> + Send + 'static,
Item = Txid,
>,
) -> Self {
self.txids = Box::new(ExactSizeChain::new(self.txids, txids.into_iter()));
self
}
/// Chain on additional [`OutPoint`]s that will be synced against.
///
/// This consumes the [`SyncRequest`] and returns the updated one.
#[must_use]
pub fn chain_outpoints(
mut self,
outpoints: impl IntoIterator<
IntoIter = impl ExactSizeIterator<Item = OutPoint> + Send + 'static,
Item = OutPoint,
>,
) -> Self {
self.outpoints = Box::new(ExactSizeChain::new(self.outpoints, outpoints.into_iter()));
self
}
/// Add a closure that will be called for [`Script`]s previously added to this request.
///
/// This consumes the [`SyncRequest`] and returns the updated one.
#[must_use]
pub fn inspect_spks(
mut self,
mut inspect: impl FnMut(&Script) + Send + Sync + 'static,
) -> Self {
self.spks = Box::new(self.spks.inspect(move |spk| inspect(spk)));
self
}
/// Add a closure that will be called for [`Txid`]s previously added to this request.
///
/// This consumes the [`SyncRequest`] and returns the updated one.
#[must_use]
pub fn inspect_txids(mut self, mut inspect: impl FnMut(&Txid) + Send + Sync + 'static) -> Self {
self.txids = Box::new(self.txids.inspect(move |txid| inspect(txid)));
self
}
/// Add a closure that will be called for [`OutPoint`]s previously added to this request.
///
/// This consumes the [`SyncRequest`] and returns the updated one.
#[must_use]
pub fn inspect_outpoints(
mut self,
mut inspect: impl FnMut(&OutPoint) + Send + Sync + 'static,
) -> Self {
self.outpoints = Box::new(self.outpoints.inspect(move |op| inspect(op)));
self
}
/// Populate the request with revealed script pubkeys from `index` with the given `spk_range`.
///
/// This consumes the [`SyncRequest`] and returns the updated one.
#[cfg(feature = "miniscript")]
#[must_use]
pub fn populate_with_revealed_spks<K: Clone + Ord + Debug + Send + Sync>(
self,
index: &crate::keychain::KeychainTxOutIndex<K>,
spk_range: impl RangeBounds<K>,
) -> Self {
use alloc::borrow::ToOwned;
self.chain_spks(
index
.revealed_spks(spk_range)
.map(|(_, _, spk)| spk.to_owned())
.collect::<Vec<_>>(),
)
}
}
/// Data returned from a spk-based blockchain client sync.
///
/// See also [`SyncRequest`].
pub struct SyncResult<A = ConfirmationTimeHeightAnchor> {
/// The update to apply to the receiving [`TxGraph`].
pub graph_update: TxGraph<A>,
/// The update to apply to the receiving [`LocalChain`](crate::local_chain::LocalChain).
pub chain_update: CheckPoint,
}
/// Data required to perform a spk-based blockchain client full scan.
///
/// A client full scan iterates through all the scripts for the given keychains, fetching relevant
/// data until some stop gap number of scripts is found that have no data. This operation is
/// generally only used when importing or restoring previously used keychains in which the list of
/// used scripts is not known. The full scan process also updates the chain from the given [`CheckPoint`].
pub struct FullScanRequest<K> {
/// A checkpoint for the current [`LocalChain::tip`].
/// The full scan process will return a new chain update that extends this tip.
///
/// [`LocalChain::tip`]: crate::local_chain::LocalChain::tip
pub chain_tip: CheckPoint,
/// Iterators of script pubkeys indexed by the keychain index.
pub spks_by_keychain: BTreeMap<K, Box<dyn Iterator<Item = (u32, ScriptBuf)> + Send>>,
}
impl<K: Ord + Clone> FullScanRequest<K> {
/// Construct a new [`FullScanRequest`] from a given `chain_tip`.
#[must_use]
pub fn from_chain_tip(chain_tip: CheckPoint) -> Self {
Self {
chain_tip,
spks_by_keychain: BTreeMap::new(),
}
}
/// Construct a new [`FullScanRequest`] from a given `chain_tip` and `index`.
///
/// Unbounded script pubkey iterators for each keychain (`K`) are extracted using
/// [`KeychainTxOutIndex::all_unbounded_spk_iters`] and is used to populate the
/// [`FullScanRequest`].
///
/// [`KeychainTxOutIndex::all_unbounded_spk_iters`]: crate::keychain::KeychainTxOutIndex::all_unbounded_spk_iters
#[cfg(feature = "miniscript")]
#[must_use]
pub fn from_keychain_txout_index(
chain_tip: CheckPoint,
index: &crate::keychain::KeychainTxOutIndex<K>,
) -> Self
where
K: Debug,
{
let mut req = Self::from_chain_tip(chain_tip);
for (keychain, spks) in index.all_unbounded_spk_iters() {
req = req.set_spks_for_keychain(keychain, spks);
}
req
}
/// Set the [`Script`]s for a given `keychain`.
///
/// This consumes the [`FullScanRequest`] and returns the updated one.
#[must_use]
pub fn set_spks_for_keychain(
mut self,
keychain: K,
spks: impl IntoIterator<IntoIter = impl Iterator<Item = (u32, ScriptBuf)> + Send + 'static>,
) -> Self {
self.spks_by_keychain
.insert(keychain, Box::new(spks.into_iter()));
self
}
/// Chain on additional [`Script`]s that will be synced against.
///
/// This consumes the [`FullScanRequest`] and returns the updated one.
#[must_use]
pub fn chain_spks_for_keychain(
mut self,
keychain: K,
spks: impl IntoIterator<IntoIter = impl Iterator<Item = (u32, ScriptBuf)> + Send + 'static>,
) -> Self {
match self.spks_by_keychain.remove(&keychain) {
// clippy here suggests to remove `into_iter` from `spks.into_iter()`, but doing so
// results in a compilation error
#[allow(clippy::useless_conversion)]
Some(keychain_spks) => self
.spks_by_keychain
.insert(keychain, Box::new(keychain_spks.chain(spks.into_iter()))),
None => self
.spks_by_keychain
.insert(keychain, Box::new(spks.into_iter())),
};
self
}
/// Add a closure that will be called for every [`Script`] previously added to any keychain in
/// this request.
///
/// This consumes the [`SyncRequest`] and returns the updated one.
#[must_use]
pub fn inspect_spks_for_all_keychains(
mut self,
inspect: impl FnMut(K, u32, &Script) + Send + Sync + Clone + 'static,
) -> Self
where
K: Send + 'static,
{
for (keychain, spks) in core::mem::take(&mut self.spks_by_keychain) {
let mut inspect = inspect.clone();
self.spks_by_keychain.insert(
keychain.clone(),
Box::new(spks.inspect(move |(i, spk)| inspect(keychain.clone(), *i, spk))),
);
}
self
}
/// Add a closure that will be called for every [`Script`] previously added to a given
/// `keychain` in this request.
///
/// This consumes the [`SyncRequest`] and returns the updated one.
#[must_use]
pub fn inspect_spks_for_keychain(
mut self,
keychain: K,
mut inspect: impl FnMut(u32, &Script) + Send + Sync + 'static,
) -> Self
where
K: Send + 'static,
{
if let Some(spks) = self.spks_by_keychain.remove(&keychain) {
self.spks_by_keychain.insert(
keychain,
Box::new(spks.inspect(move |(i, spk)| inspect(*i, spk))),
);
}
self
}
}
/// Data returned from a spk-based blockchain client full scan.
///
/// See also [`FullScanRequest`].
pub struct FullScanResult<K, A = ConfirmationTimeHeightAnchor> {
/// The update to apply to the receiving [`LocalChain`](crate::local_chain::LocalChain).
pub graph_update: TxGraph<A>,
/// The update to apply to the receiving [`TxGraph`].
pub chain_update: CheckPoint,
/// Last active indices for the corresponding keychains (`K`).
pub last_active_indices: BTreeMap<K, u32>,
}
/// A version of [`core::iter::Chain`] which can combine two [`ExactSizeIterator`]s to form a new
/// [`ExactSizeIterator`].
///
/// The danger of this is explained in [the `ExactSizeIterator` docs]
/// (https://doc.rust-lang.org/core/iter/trait.ExactSizeIterator.html#when-shouldnt-an-adapter-be-exactsizeiterator).
/// This does not apply here since it would be impossible to scan an item count that overflows
/// `usize` anyway.
struct ExactSizeChain<A, B, I> {
a: Option<A>,
b: Option<B>,
i: PhantomData<I>,
}
impl<A, B, I> ExactSizeChain<A, B, I> {
fn new(a: A, b: B) -> Self {
ExactSizeChain {
a: Some(a),
b: Some(b),
i: PhantomData,
}
}
}
impl<A, B, I> Iterator for ExactSizeChain<A, B, I>
where
A: Iterator<Item = I>,
B: Iterator<Item = I>,
{
type Item = I;
fn next(&mut self) -> Option<Self::Item> {
if let Some(a) = &mut self.a {
let item = a.next();
if item.is_some() {
return item;
}
self.a = None;
}
if let Some(b) = &mut self.b {
let item = b.next();
if item.is_some() {
return item;
}
self.b = None;
}
None
}
}
impl<A, B, I> ExactSizeIterator for ExactSizeChain<A, B, I>
where
A: ExactSizeIterator<Item = I>,
B: ExactSizeIterator<Item = I>,
{
fn len(&self) -> usize {
let a_len = self.a.as_ref().map(|a| a.len()).unwrap_or(0);
let b_len = self.b.as_ref().map(|a| a.len()).unwrap_or(0);
a_len + b_len
}
}