feat(esplora): greatly simplify update_local_chain
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25653d71b8
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f05e8502e6
@ -2,14 +2,14 @@ use async_trait::async_trait;
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use bdk_chain::collections::btree_map;
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use bdk_chain::{
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bitcoin::{BlockHash, OutPoint, ScriptBuf, Txid},
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collections::{BTreeMap, BTreeSet},
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collections::BTreeMap,
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local_chain::{self, CheckPoint},
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BlockId, ConfirmationTimeHeightAnchor, TxGraph,
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};
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use esplora_client::{Error, TxStatus};
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use futures::{stream::FuturesOrdered, TryStreamExt};
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use crate::{anchor_from_status, ASSUME_FINAL_DEPTH};
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use crate::anchor_from_status;
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/// Trait to extend the functionality of [`esplora_client::AsyncClient`].
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///
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@ -85,10 +85,11 @@ impl EsploraAsyncExt for esplora_client::AsyncClient {
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local_tip: CheckPoint,
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request_heights: impl IntoIterator<IntoIter = impl Iterator<Item = u32> + Send> + Send,
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) -> Result<local_chain::Update, Error> {
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let request_heights = request_heights.into_iter().collect::<BTreeSet<_>>();
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let new_tip_height = self.get_height().await?;
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// atomically fetch blocks from esplora
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// Atomically fetch latest blocks from Esplora. This way, we avoid creating an update with
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// an inconsistent set of blocks (assuming that a reorg depth cannot be greater than the
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// latest blocks fetched).
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let mut fetched_blocks = {
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let heights = (0..=new_tip_height).rev();
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let hashes = self
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@ -99,7 +100,8 @@ impl EsploraAsyncExt for esplora_client::AsyncClient {
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heights.zip(hashes).collect::<BTreeMap<u32, BlockHash>>()
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};
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// fetch heights that the caller is interested in
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// fetch blocks of heights that the caller is interested in, reusing latest blocks that are
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// already fetched.
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for height in request_heights {
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// do not fetch blocks higher than remote tip
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if height > new_tip_height {
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@ -107,81 +109,32 @@ impl EsploraAsyncExt for esplora_client::AsyncClient {
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}
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// only fetch what is missing
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if let btree_map::Entry::Vacant(entry) = fetched_blocks.entry(height) {
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let hash = self.get_block_hash(height).await?;
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entry.insert(hash);
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entry.insert(self.get_block_hash(height).await?);
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}
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}
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// find the earliest point of agreement between local chain and fetched chain
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let earliest_agreement_cp = {
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let mut earliest_agreement_cp = Option::<CheckPoint>::None;
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let local_tip_height = local_tip.height();
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for local_cp in local_tip.iter() {
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let local_block = local_cp.block_id();
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// the updated hash (block hash at this height after the update), can either be:
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// 1. a block that already existed in `fetched_blocks`
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// 2. a block that exists locally and at least has a depth of ASSUME_FINAL_DEPTH
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// 3. otherwise we can freshly fetch the block from remote, which is safe as it
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// is guaranteed that this would be at or below ASSUME_FINAL_DEPTH from the
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// remote tip
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let updated_hash = match fetched_blocks.entry(local_block.height) {
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btree_map::Entry::Occupied(entry) => *entry.get(),
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btree_map::Entry::Vacant(entry) => *entry.insert(
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if local_tip_height - local_block.height >= ASSUME_FINAL_DEPTH {
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local_block.hash
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} else {
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self.get_block_hash(local_block.height).await?
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},
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),
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};
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// since we may introduce blocks below the point of agreement, we cannot break
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// here unconditionally - we only break if we guarantee there are no new heights
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// below our current local checkpoint
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if local_block.hash == updated_hash {
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earliest_agreement_cp = Some(local_cp);
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let first_new_height = *fetched_blocks
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.keys()
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.next()
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.expect("must have at least one new block");
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if first_new_height >= local_block.height {
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break;
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}
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}
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// Ensure `fetched_blocks` can create an update that connects with the original chain.
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for (height, local_hash) in local_tip.iter().map(|cp| (cp.height(), cp.hash())) {
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if height > new_tip_height {
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continue;
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}
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earliest_agreement_cp
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};
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let tip = {
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// first checkpoint to use for the update chain
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let first_cp = match earliest_agreement_cp {
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Some(cp) => cp,
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None => {
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let (&height, &hash) = fetched_blocks
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.iter()
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.next()
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.expect("must have at least one new block");
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CheckPoint::new(BlockId { height, hash })
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let fetched_hash = match fetched_blocks.entry(height) {
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btree_map::Entry::Occupied(entry) => *entry.get(),
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btree_map::Entry::Vacant(entry) => {
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*entry.insert(self.get_block_hash(height).await?)
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}
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};
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// transform fetched chain into the update chain
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fetched_blocks
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// we exclude anything at or below the first cp of the update chain otherwise
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// building the chain will fail
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.split_off(&(first_cp.height() + 1))
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.into_iter()
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.map(|(height, hash)| BlockId { height, hash })
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.fold(first_cp, |prev_cp, block| {
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prev_cp.push(block).expect("must extend checkpoint")
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})
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};
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// We have found point of agreement so the update will connect!
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if fetched_hash == local_hash {
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break;
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}
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}
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Ok(local_chain::Update {
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tip,
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tip: CheckPoint::from_block_ids(fetched_blocks.into_iter().map(BlockId::from))
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.expect("must be in height order"),
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introduce_older_blocks: true,
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})
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}
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@ -1,7 +1,7 @@
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use std::thread::JoinHandle;
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use bdk_chain::collections::btree_map;
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use bdk_chain::collections::{BTreeMap, BTreeSet};
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use bdk_chain::collections::BTreeMap;
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use bdk_chain::{
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bitcoin::{BlockHash, OutPoint, ScriptBuf, Txid},
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local_chain::{self, CheckPoint},
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@ -9,7 +9,7 @@ use bdk_chain::{
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};
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use esplora_client::{Error, TxStatus};
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use crate::{anchor_from_status, ASSUME_FINAL_DEPTH};
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use crate::anchor_from_status;
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/// Trait to extend the functionality of [`esplora_client::BlockingClient`].
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///
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@ -78,10 +78,11 @@ impl EsploraExt for esplora_client::BlockingClient {
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local_tip: CheckPoint,
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request_heights: impl IntoIterator<Item = u32>,
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) -> Result<local_chain::Update, Error> {
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let request_heights = request_heights.into_iter().collect::<BTreeSet<_>>();
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let new_tip_height = self.get_height()?;
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// atomically fetch blocks from esplora
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// Atomically fetch latest blocks from Esplora. This way, we avoid creating an update with
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// an inconsistent set of blocks (assuming that a reorg depth cannot be greater than the
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// latest blocks fetched).
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let mut fetched_blocks = {
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let heights = (0..=new_tip_height).rev();
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let hashes = self
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@ -91,7 +92,8 @@ impl EsploraExt for esplora_client::BlockingClient {
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heights.zip(hashes).collect::<BTreeMap<u32, BlockHash>>()
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};
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// fetch heights that the caller is interested in
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// fetch blocks of heights that the caller is interested in, reusing latest blocks that are
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// already fetched.
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for height in request_heights {
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// do not fetch blocks higher than remote tip
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if height > new_tip_height {
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@ -99,81 +101,30 @@ impl EsploraExt for esplora_client::BlockingClient {
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}
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// only fetch what is missing
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if let btree_map::Entry::Vacant(entry) = fetched_blocks.entry(height) {
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let hash = self.get_block_hash(height)?;
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entry.insert(hash);
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entry.insert(self.get_block_hash(height)?);
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}
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}
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// find the earliest point of agreement between local chain and fetched chain
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let earliest_agreement_cp = {
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let mut earliest_agreement_cp = Option::<CheckPoint>::None;
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let local_tip_height = local_tip.height();
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for local_cp in local_tip.iter() {
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let local_block = local_cp.block_id();
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// the updated hash (block hash at this height after the update), can either be:
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// 1. a block that already existed in `fetched_blocks`
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// 2. a block that exists locally and at least has a depth of ASSUME_FINAL_DEPTH
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// 3. otherwise we can freshly fetch the block from remote, which is safe as it
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// is guaranteed that this would be at or below ASSUME_FINAL_DEPTH from the
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// remote tip
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let updated_hash = match fetched_blocks.entry(local_block.height) {
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btree_map::Entry::Occupied(entry) => *entry.get(),
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btree_map::Entry::Vacant(entry) => *entry.insert(
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if local_tip_height - local_block.height >= ASSUME_FINAL_DEPTH {
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local_block.hash
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} else {
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self.get_block_hash(local_block.height)?
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},
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),
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};
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// since we may introduce blocks below the point of agreement, we cannot break
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// here unconditionally - we only break if we guarantee there are no new heights
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// below our current local checkpoint
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if local_block.hash == updated_hash {
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earliest_agreement_cp = Some(local_cp);
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let first_new_height = *fetched_blocks
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.keys()
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.next()
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.expect("must have at least one new block");
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if first_new_height >= local_block.height {
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break;
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}
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}
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// Ensure `fetched_blocks` can create an update that connects with the original chain.
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for (height, local_hash) in local_tip.iter().map(|cp| (cp.height(), cp.hash())) {
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if height > new_tip_height {
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continue;
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}
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earliest_agreement_cp
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};
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let tip = {
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// first checkpoint to use for the update chain
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let first_cp = match earliest_agreement_cp {
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Some(cp) => cp,
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None => {
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let (&height, &hash) = fetched_blocks
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.iter()
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.next()
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.expect("must have at least one new block");
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CheckPoint::new(BlockId { height, hash })
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}
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let fetched_hash = match fetched_blocks.entry(height) {
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btree_map::Entry::Occupied(entry) => *entry.get(),
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btree_map::Entry::Vacant(entry) => *entry.insert(self.get_block_hash(height)?),
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};
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// transform fetched chain into the update chain
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fetched_blocks
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// we exclude anything at or below the first cp of the update chain otherwise
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// building the chain will fail
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.split_off(&(first_cp.height() + 1))
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.into_iter()
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.map(|(height, hash)| BlockId { height, hash })
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.fold(first_cp, |prev_cp, block| {
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prev_cp.push(block).expect("must extend checkpoint")
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})
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};
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// We have found point of agreement so the update will connect!
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if fetched_hash == local_hash {
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break;
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}
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}
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Ok(local_chain::Update {
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tip,
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tip: CheckPoint::from_block_ids(fetched_blocks.into_iter().map(BlockId::from))
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.expect("must be in height order"),
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introduce_older_blocks: true,
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})
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}
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@ -31,8 +31,6 @@ mod async_ext;
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#[cfg(feature = "async")]
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pub use async_ext::*;
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const ASSUME_FINAL_DEPTH: u32 = 15;
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fn anchor_from_status(status: &TxStatus) -> Option<ConfirmationTimeHeightAnchor> {
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if let TxStatus {
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block_height: Some(height),
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