[bdk_chain_redesign] Better names, comments and generic bounds

* Instead of implementing `ChainPosition` for `ObservedIn<BlockId>` to
  use `FullTxOut` methods (`is_spendable_at` and `is_mature`), we create
  alternative versions of those methods that require bounds with `Anchor`.
  This removes all `ObservedIn<A>: ChainPosition` bounds for methods of
  `IndexedTxGraph`.

* Various improvements to comments and names.
This commit is contained in:
志宇 2023-04-05 16:39:54 +08:00
parent 6e59dce10b
commit 89cfa4d78e
No known key found for this signature in database
GPG Key ID: F6345C9837C2BDE8
6 changed files with 163 additions and 142 deletions

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@ -6,49 +6,21 @@ use crate::{
};
/// Represents an observation of some chain data.
///
/// The generic `A` should be a [`BlockAnchor`] implementation.
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, core::hash::Hash)]
pub enum ObservedIn<A> {
/// The chain data is seen in a block identified by `A`.
Block(A),
pub enum ObservedAs<A> {
/// The chain data is seen as confirmed, and in anchored by `A`.
Confirmed(A),
/// The chain data is seen in mempool at this given timestamp.
/// TODO: Call this `Unconfirmed`.
Mempool(u64),
Unconfirmed(u64),
}
impl<A: Clone> ObservedIn<&A> {
pub fn into_owned(self) -> ObservedIn<A> {
impl<A: Clone> ObservedAs<&A> {
pub fn cloned(self) -> ObservedAs<A> {
match self {
ObservedIn::Block(a) => ObservedIn::Block(a.clone()),
ObservedIn::Mempool(last_seen) => ObservedIn::Mempool(last_seen),
}
}
}
impl ChainPosition for ObservedIn<BlockId> {
fn height(&self) -> TxHeight {
match self {
ObservedIn::Block(block_id) => TxHeight::Confirmed(block_id.height),
ObservedIn::Mempool(_) => TxHeight::Unconfirmed,
}
}
fn max_ord_of_height(height: TxHeight) -> Self {
match height {
TxHeight::Confirmed(height) => ObservedIn::Block(BlockId {
height,
hash: Hash::from_inner([u8::MAX; 32]),
}),
TxHeight::Unconfirmed => Self::Mempool(u64::MAX),
}
}
fn min_ord_of_height(height: TxHeight) -> Self {
match height {
TxHeight::Confirmed(height) => ObservedIn::Block(BlockId {
height,
hash: Hash::from_inner([u8::MIN; 32]),
}),
TxHeight::Unconfirmed => Self::Mempool(u64::MIN),
ObservedAs::Confirmed(a) => ObservedAs::Confirmed(a.clone()),
ObservedAs::Unconfirmed(last_seen) => ObservedAs::Unconfirmed(last_seen),
}
}
}
@ -217,20 +189,20 @@ impl From<(&u32, &BlockHash)> for BlockId {
/// A `TxOut` with as much data as we can retrieve about it
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
pub struct FullTxOut<I> {
pub struct FullTxOut<P> {
/// The location of the `TxOut`.
pub outpoint: OutPoint,
/// The `TxOut`.
pub txout: TxOut,
/// The position of the transaction in `outpoint` in the overall chain.
pub chain_position: I,
pub chain_position: P,
/// The txid and chain position of the transaction (if any) that has spent this output.
pub spent_by: Option<(I, Txid)>,
pub spent_by: Option<(P, Txid)>,
/// Whether this output is on a coinbase transaction.
pub is_on_coinbase: bool,
}
impl<I: ChainPosition> FullTxOut<I> {
impl<P: ChainPosition> FullTxOut<P> {
/// Whether the utxo is/was/will be spendable at `height`.
///
/// It is spendable if it is not an immature coinbase output and no spending tx has been
@ -269,15 +241,63 @@ impl<I: ChainPosition> FullTxOut<I> {
}
}
impl<A: Clone> FullTxOut<ObservedIn<&A>> {
pub fn into_owned(self) -> FullTxOut<ObservedIn<A>> {
FullTxOut {
outpoint: self.outpoint,
txout: self.txout,
chain_position: self.chain_position.into_owned(),
spent_by: self.spent_by.map(|(o, txid)| (o.into_owned(), txid)),
is_on_coinbase: self.is_on_coinbase,
impl<A: BlockAnchor> FullTxOut<ObservedAs<A>> {
/// Whether the `txout` is considered mature.
///
/// This is the alternative version of [`is_mature`] which depends on `chain_position` being a
/// [`ObservedAs<A>`] where `A` implements [`BlockAnchor`].
///
/// [`is_mature`]: Self::is_mature
pub fn is_observed_as_mature(&self, tip: u32) -> bool {
if !self.is_on_coinbase {
return false;
}
let tx_height = match &self.chain_position {
ObservedAs::Confirmed(anchor) => anchor.anchor_block().height,
ObservedAs::Unconfirmed(_) => {
debug_assert!(false, "coinbase tx can never be unconfirmed");
return false;
}
};
let age = tip.saturating_sub(tx_height);
if age + 1 < COINBASE_MATURITY {
return false;
}
true
}
/// Whether the utxo is/was/will be spendable with chain `tip`.
///
/// This is the alternative version of [`is_spendable_at`] which depends on `chain_position`
/// being a [`ObservedAs<A>`] where `A` implements [`BlockAnchor`].
///
/// [`is_spendable_at`]: Self::is_spendable_at
pub fn is_observed_as_spendable(&self, tip: u32) -> bool {
if !self.is_observed_as_mature(tip) {
return false;
}
match &self.chain_position {
ObservedAs::Confirmed(anchor) => {
if anchor.anchor_block().height > tip {
return false;
}
}
// [TODO] Why are unconfirmed txs always considered unspendable here?
ObservedAs::Unconfirmed(_) => return false,
};
// if the spending tx is confirmed within tip height, the txout is no longer spendable
if let Some((ObservedAs::Confirmed(spending_anchor), _)) = &self.spent_by {
if spending_anchor.anchor_block().height <= tip {
return false;
}
}
true
}
}

View File

@ -151,7 +151,7 @@ where
let _ = inflated_chain
.insert_tx(*txid, pos.clone())
.expect("must insert since this was already in update");
let _ = inflated_graph.insert_tx(tx.clone());
let _ = inflated_graph.insert_tx(tx);
}
}
None => {
@ -212,8 +212,8 @@ where
/// the unconfirmed transaction list within the [`SparseChain`].
pub fn get_tx_in_chain(&self, txid: Txid) -> Option<(&P, &Transaction)> {
let position = self.chain.tx_position(txid)?;
let tx = self.graph.get_tx(txid).expect("must exist");
Some((position, tx))
let full_tx = self.graph.get_tx(txid).expect("must exist");
Some((position, full_tx))
}
/// Determines the changes required to insert a transaction into the inner [`ChainGraph`] and

View File

@ -4,16 +4,15 @@ use bitcoin::{OutPoint, Script, Transaction, TxOut};
use crate::{
keychain::Balance,
sparse_chain::ChainPosition,
tx_graph::{Additions, TxGraph, TxNode},
BlockAnchor, ChainOracle, FullTxOut, ObservedIn, TxIndex,
BlockAnchor, ChainOracle, FullTxOut, ObservedAs, TxIndex,
};
/// An outwards-facing view of a transaction that is part of the *best chain*'s history.
#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
pub struct TxInChain<'a, T, A> {
pub struct CanonicalTx<'a, T, A> {
/// Where the transaction is observed (in a block or in mempool).
pub observed_in: ObservedIn<&'a A>,
pub observed_as: ObservedAs<&'a A>,
/// The transaction with anchors and last seen timestamp.
pub tx: TxNode<'a, T, A>,
}
@ -140,19 +139,23 @@ impl<A: BlockAnchor, I: TxIndex> IndexedTxGraph<A, I> {
&mut self,
outpoint: OutPoint,
txout: &TxOut,
observation: ObservedIn<A>,
observation: ObservedAs<A>,
) -> IndexedAdditions<A, I::Additions> {
let last_height = match &observation {
ObservedIn::Block(anchor) => self.insert_height_internal(anchor.anchor_block().height),
ObservedIn::Mempool(_) => None,
ObservedAs::Confirmed(anchor) => {
self.insert_height_internal(anchor.anchor_block().height)
}
ObservedAs::Unconfirmed(_) => None,
};
IndexedAdditions {
graph_additions: {
let mut graph_additions = self.graph.insert_txout(outpoint, txout.clone());
graph_additions.append(match observation {
ObservedIn::Block(anchor) => self.graph.insert_anchor(outpoint.txid, anchor),
ObservedIn::Mempool(seen_at) => {
ObservedAs::Confirmed(anchor) => {
self.graph.insert_anchor(outpoint.txid, anchor)
}
ObservedAs::Unconfirmed(seen_at) => {
self.graph.insert_seen_at(outpoint.txid, seen_at)
}
});
@ -166,21 +169,23 @@ impl<A: BlockAnchor, I: TxIndex> IndexedTxGraph<A, I> {
pub fn insert_tx(
&mut self,
tx: &Transaction,
observation: ObservedIn<A>,
observation: ObservedAs<A>,
) -> IndexedAdditions<A, I::Additions> {
let txid = tx.txid();
let last_height = match &observation {
ObservedIn::Block(anchor) => self.insert_height_internal(anchor.anchor_block().height),
ObservedIn::Mempool(_) => None,
ObservedAs::Confirmed(anchor) => {
self.insert_height_internal(anchor.anchor_block().height)
}
ObservedAs::Unconfirmed(_) => None,
};
IndexedAdditions {
graph_additions: {
let mut graph_additions = self.graph.insert_tx(tx.clone());
graph_additions.append(match observation {
ObservedIn::Block(anchor) => self.graph.insert_anchor(txid, anchor),
ObservedIn::Mempool(seen_at) => self.graph.insert_seen_at(txid, seen_at),
ObservedAs::Confirmed(anchor) => self.graph.insert_anchor(txid, anchor),
ObservedAs::Unconfirmed(seen_at) => self.graph.insert_seen_at(txid, seen_at),
});
graph_additions
},
@ -192,7 +197,7 @@ impl<A: BlockAnchor, I: TxIndex> IndexedTxGraph<A, I> {
pub fn filter_and_insert_txs<'t, T>(
&mut self,
txs: T,
observation: ObservedIn<A>,
observation: ObservedAs<A>,
) -> IndexedAdditions<A, I::Additions>
where
T: Iterator<Item = &'t Transaction>,
@ -220,7 +225,7 @@ impl<A: BlockAnchor, I: TxIndex> IndexedTxGraph<A, I> {
pub fn try_list_chain_txs<'a, C>(
&'a self,
chain: C,
) -> impl Iterator<Item = Result<TxInChain<'a, Transaction, A>, C::Error>>
) -> impl Iterator<Item = Result<CanonicalTx<'a, Transaction, A>, C::Error>>
where
C: ChainOracle + 'a,
{
@ -230,7 +235,12 @@ impl<A: BlockAnchor, I: TxIndex> IndexedTxGraph<A, I> {
.filter_map(move |tx| {
self.graph
.try_get_chain_position(&chain, tx.txid)
.map(|v| v.map(|observed_in| TxInChain { observed_in, tx }))
.map(|v| {
v.map(|observed_in| CanonicalTx {
observed_as: observed_in,
tx,
})
})
.transpose()
})
}
@ -238,7 +248,7 @@ impl<A: BlockAnchor, I: TxIndex> IndexedTxGraph<A, I> {
pub fn list_chain_txs<'a, C>(
&'a self,
chain: C,
) -> impl Iterator<Item = TxInChain<'a, Transaction, A>>
) -> impl Iterator<Item = CanonicalTx<'a, Transaction, A>>
where
C: ChainOracle<Error = Infallible> + 'a,
{
@ -249,10 +259,9 @@ impl<A: BlockAnchor, I: TxIndex> IndexedTxGraph<A, I> {
pub fn try_list_chain_txouts<'a, C>(
&'a self,
chain: C,
) -> impl Iterator<Item = Result<FullTxOut<ObservedIn<A>>, C::Error>> + 'a
) -> impl Iterator<Item = Result<FullTxOut<ObservedAs<A>>, C::Error>> + 'a
where
C: ChainOracle + 'a,
ObservedIn<A>: ChainPosition,
{
self.graph
.all_txouts()
@ -263,13 +272,13 @@ impl<A: BlockAnchor, I: TxIndex> IndexedTxGraph<A, I> {
let is_on_coinbase = graph_tx.is_coin_base();
let chain_position = match self.graph.try_get_chain_position(&chain, op.txid) {
Ok(Some(observed_at)) => observed_at.into_owned(),
Ok(Some(observed_at)) => observed_at.cloned(),
Ok(None) => return None,
Err(err) => return Some(Err(err)),
};
let spent_by = match self.graph.try_get_spend_in_chain(&chain, op) {
Ok(Some((obs, txid))) => Some((obs.into_owned(), txid)),
Ok(Some((obs, txid))) => Some((obs.cloned(), txid)),
Ok(None) => None,
Err(err) => return Some(Err(err)),
};
@ -289,10 +298,9 @@ impl<A: BlockAnchor, I: TxIndex> IndexedTxGraph<A, I> {
pub fn list_chain_txouts<'a, C>(
&'a self,
chain: C,
) -> impl Iterator<Item = FullTxOut<ObservedIn<A>>> + 'a
) -> impl Iterator<Item = FullTxOut<ObservedAs<A>>> + 'a
where
C: ChainOracle<Error = Infallible> + 'a,
ObservedIn<A>: ChainPosition,
{
self.try_list_chain_txouts(chain)
.map(|r| r.expect("error in infallible"))
@ -302,10 +310,9 @@ impl<A: BlockAnchor, I: TxIndex> IndexedTxGraph<A, I> {
pub fn try_list_chain_utxos<'a, C>(
&'a self,
chain: C,
) -> impl Iterator<Item = Result<FullTxOut<ObservedIn<A>>, C::Error>> + 'a
) -> impl Iterator<Item = Result<FullTxOut<ObservedAs<A>>, C::Error>> + 'a
where
C: ChainOracle + 'a,
ObservedIn<A>: ChainPosition,
{
self.try_list_chain_txouts(chain)
.filter(|r| !matches!(r, Ok(txo) if txo.spent_by.is_none()))
@ -314,10 +321,9 @@ impl<A: BlockAnchor, I: TxIndex> IndexedTxGraph<A, I> {
pub fn list_chain_utxos<'a, C>(
&'a self,
chain: C,
) -> impl Iterator<Item = FullTxOut<ObservedIn<A>>> + 'a
) -> impl Iterator<Item = FullTxOut<ObservedAs<A>>> + 'a
where
C: ChainOracle<Error = Infallible> + 'a,
ObservedIn<A>: ChainPosition,
{
self.try_list_chain_utxos(chain)
.map(|r| r.expect("error is infallible"))
@ -331,7 +337,6 @@ impl<A: BlockAnchor, I: TxIndex> IndexedTxGraph<A, I> {
) -> Result<Balance, C::Error>
where
C: ChainOracle,
ObservedIn<A>: ChainPosition + Clone,
F: FnMut(&Script) -> bool,
{
let mut immature = 0;
@ -343,16 +348,16 @@ impl<A: BlockAnchor, I: TxIndex> IndexedTxGraph<A, I> {
let txout = res?;
match &txout.chain_position {
ObservedIn::Block(_) => {
ObservedAs::Confirmed(_) => {
if txout.is_on_coinbase {
if txout.is_mature(tip) {
if txout.is_observed_as_mature(tip) {
confirmed += txout.txout.value;
} else {
immature += txout.txout.value;
}
}
}
ObservedIn::Mempool(_) => {
ObservedAs::Unconfirmed(_) => {
if should_trust(&txout.txout.script_pubkey) {
trusted_pending += txout.txout.value;
} else {
@ -373,7 +378,6 @@ impl<A: BlockAnchor, I: TxIndex> IndexedTxGraph<A, I> {
pub fn balance<C, F>(&self, chain: C, tip: u32, should_trust: F) -> Balance
where
C: ChainOracle<Error = Infallible>,
ObservedIn<A>: ChainPosition + Clone,
F: FnMut(&Script) -> bool,
{
self.try_balance(chain, tip, should_trust)
@ -383,12 +387,11 @@ impl<A: BlockAnchor, I: TxIndex> IndexedTxGraph<A, I> {
pub fn try_balance_at<C>(&self, chain: C, height: u32) -> Result<u64, C::Error>
where
C: ChainOracle,
ObservedIn<A>: ChainPosition + Clone,
{
let mut sum = 0;
for txo_res in self.try_list_chain_txouts(chain) {
let txo = txo_res?;
if txo.is_spendable_at(height) {
if txo.is_observed_as_spendable(height) {
sum += txo.txout.value;
}
}
@ -398,7 +401,6 @@ impl<A: BlockAnchor, I: TxIndex> IndexedTxGraph<A, I> {
pub fn balance_at<C>(&self, chain: C, height: u32) -> u64
where
C: ChainOracle<Error = Infallible>,
ObservedIn<A>: ChainPosition + Clone,
{
self.try_balance_at(chain, height)
.expect("error is infallible")

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@ -123,7 +123,7 @@ impl LocalChain {
/// Updates [`LocalChain`] with an update [`LocalChain`].
///
/// This is equivilant to calling [`determine_changeset`] and [`apply_changeset`] in sequence.
/// This is equivalent to calling [`determine_changeset`] and [`apply_changeset`] in sequence.
///
/// [`determine_changeset`]: Self::determine_changeset
/// [`apply_changeset`]: Self::apply_changeset

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@ -457,7 +457,7 @@ impl<P: core::fmt::Debug> core::fmt::Display for UpdateError<P> {
#[cfg(feature = "std")]
impl<P: core::fmt::Debug> std::error::Error for UpdateError<P> {}
impl<P: ChainPosition> ChainOracle for SparseChain<P> {
impl<P> ChainOracle for SparseChain<P> {
type Error = Infallible;
fn get_tip_in_best_chain(&self) -> Result<Option<BlockId>, Self::Error> {
@ -473,7 +473,7 @@ impl<P: ChainPosition> ChainOracle for SparseChain<P> {
}
}
impl<P: ChainPosition> SparseChain<P> {
impl<P> SparseChain<P> {
/// Creates a new chain from a list of block hashes and heights. The caller must guarantee they
/// are in the same chain.
pub fn from_checkpoints<C>(checkpoints: C) -> Self
@ -504,13 +504,6 @@ impl<P: ChainPosition> SparseChain<P> {
.map(|&hash| BlockId { height, hash })
}
/// Return the [`ChainPosition`] of a `txid`.
///
/// This returns [`None`] if the transaction does not exist.
pub fn tx_position(&self, txid: Txid) -> Option<&P> {
self.txid_to_pos.get(&txid)
}
/// Return a [`BTreeMap`] of all checkpoints (block hashes by height).
pub fn checkpoints(&self) -> &BTreeMap<u32, BlockHash> {
&self.checkpoints
@ -526,6 +519,47 @@ impl<P: ChainPosition> SparseChain<P> {
.map(|(&height, &hash)| BlockId { height, hash })
}
/// Returns the value set as the checkpoint limit.
///
/// Refer to [`set_checkpoint_limit`].
///
/// [`set_checkpoint_limit`]: Self::set_checkpoint_limit
pub fn checkpoint_limit(&self) -> Option<usize> {
self.checkpoint_limit
}
/// Set the checkpoint limit.
///
/// The checkpoint limit restricts the number of checkpoints that can be stored in [`Self`].
/// Oldest checkpoints are pruned first.
pub fn set_checkpoint_limit(&mut self, limit: Option<usize>) {
self.checkpoint_limit = limit;
self.prune_checkpoints();
}
fn prune_checkpoints(&mut self) -> Option<BTreeMap<u32, BlockHash>> {
let limit = self.checkpoint_limit?;
// find the last height to be pruned
let last_height = *self.checkpoints.keys().rev().nth(limit)?;
// first height to be kept
let keep_height = last_height + 1;
let mut split = self.checkpoints.split_off(&keep_height);
core::mem::swap(&mut self.checkpoints, &mut split);
Some(split)
}
}
impl<P: ChainPosition> SparseChain<P> {
/// Return the [`ChainPosition`] of a `txid`.
///
/// This returns [`None`] if the transaction does not exist.
pub fn tx_position(&self, txid: Txid) -> Option<&P> {
self.txid_to_pos.get(&txid)
}
/// Preview changes of updating [`Self`] with another chain that connects to it.
///
/// If the `update` wishes to introduce confirmed transactions, it must contain a checkpoint
@ -936,24 +970,6 @@ impl<P: ChainPosition> SparseChain<P> {
})
}
/// Returns the value set as the checkpoint limit.
///
/// Refer to [`set_checkpoint_limit`].
///
/// [`set_checkpoint_limit`]: Self::set_checkpoint_limit
pub fn checkpoint_limit(&self) -> Option<usize> {
self.checkpoint_limit
}
/// Set the checkpoint limit.
///
/// The checkpoint limit restricts the number of checkpoints that can be stored in [`Self`].
/// Oldest checkpoints are pruned first.
pub fn set_checkpoint_limit(&mut self, limit: Option<usize>) {
self.checkpoint_limit = limit;
self.prune_checkpoints();
}
/// Return [`Txid`]s that would be added to the sparse chain if this `changeset` was applied.
pub fn changeset_additions<'a>(
&'a self,
@ -969,20 +985,6 @@ impl<P: ChainPosition> SparseChain<P> {
.map(|(&txid, _)| txid)
}
fn prune_checkpoints(&mut self) -> Option<BTreeMap<u32, BlockHash>> {
let limit = self.checkpoint_limit?;
// find the last height to be pruned
let last_height = *self.checkpoints.keys().rev().nth(limit)?;
// first height to be kept
let keep_height = last_height + 1;
let mut split = self.checkpoints.split_off(&keep_height);
core::mem::swap(&mut self.checkpoints, &mut split);
Some(split)
}
/// Finds the transaction in the chain that spends `outpoint`.
///
/// [`TxGraph`] is used to provide the spend relationships.

View File

@ -55,7 +55,7 @@
//! assert!(additions.is_empty());
//! ```
use crate::{collections::*, BlockAnchor, ChainOracle, ForEachTxOut, ObservedIn};
use crate::{collections::*, BlockAnchor, ChainOracle, ForEachTxOut, ObservedAs};
use alloc::vec::Vec;
use bitcoin::{OutPoint, Transaction, TxOut, Txid};
use core::{
@ -91,10 +91,7 @@ impl<A> Default for TxGraph<A> {
}
}
// pub type InChainTx<'a, T, A> = (ObservedIn<&'a A>, TxInGraph<'a, T, A>);
// pub type InChainTxOut<'a, I, A> = (&'a I, FullTxOut<ObservedIn<&'a A>>);
/// An outward-facing view of a transaction node that resides in a [`TxGraph`].
/// An outward-facing representation of a (transaction) node in the [`TxGraph`].
#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
pub struct TxNode<'a, T, A> {
/// Txid of the transaction.
@ -601,7 +598,7 @@ impl<A: BlockAnchor> TxGraph<A> {
&self,
chain: C,
txid: Txid,
) -> Result<Option<ObservedIn<&A>>, C::Error>
) -> Result<Option<ObservedAs<&A>>, C::Error>
where
C: ChainOracle,
{
@ -614,7 +611,7 @@ impl<A: BlockAnchor> TxGraph<A> {
for anchor in anchors {
if chain.is_block_in_best_chain(anchor.anchor_block())? {
return Ok(Some(ObservedIn::Block(anchor)));
return Ok(Some(ObservedAs::Confirmed(anchor)));
}
}
@ -643,10 +640,10 @@ impl<A: BlockAnchor> TxGraph<A> {
}
}
Ok(Some(ObservedIn::Mempool(last_seen)))
Ok(Some(ObservedAs::Unconfirmed(last_seen)))
}
pub fn get_chain_position<C>(&self, chain: C, txid: Txid) -> Option<ObservedIn<&A>>
pub fn get_chain_position<C>(&self, chain: C, txid: Txid) -> Option<ObservedAs<&A>>
where
C: ChainOracle<Error = Infallible>,
{
@ -658,7 +655,7 @@ impl<A: BlockAnchor> TxGraph<A> {
&self,
chain: C,
outpoint: OutPoint,
) -> Result<Option<(ObservedIn<&A>, Txid)>, C::Error>
) -> Result<Option<(ObservedAs<&A>, Txid)>, C::Error>
where
C: ChainOracle,
{
@ -678,7 +675,7 @@ impl<A: BlockAnchor> TxGraph<A> {
Ok(None)
}
pub fn get_chain_spend<C>(&self, chain: C, outpoint: OutPoint) -> Option<(ObservedIn<&A>, Txid)>
pub fn get_chain_spend<C>(&self, chain: C, outpoint: OutPoint) -> Option<(ObservedAs<&A>, Txid)>
where
C: ChainOracle<Error = Infallible>,
{