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@evanlinjin
evanlinjin committed Mar 17, 2024
1 parent ded2bd5 commit 013f7cc
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Showing 7 changed files with 126 additions and 188 deletions.
11 changes: 3 additions & 8 deletions crates/bdk/src/wallet/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1130,18 +1130,13 @@ impl<D> Wallet<D> {
// anchor tx to checkpoint with lowest height that is >= position's height
let anchor = self
.chain
.blocks()
.range(height..)
.next()
.query_from(height)
.ok_or(InsertTxError::ConfirmationHeightCannotBeGreaterThanTip {
tip_height: self.chain.tip().height(),
tx_height: height,
})
.map(|(&anchor_height, &hash)| ConfirmationTimeHeightAnchor {
anchor_block: BlockId {
height: anchor_height,
hash,
},
.map(|anchor_cp| ConfirmationTimeHeightAnchor {
anchor_block: anchor_cp.block_id(),
confirmation_height: height,
confirmation_time: time,
})?;
Expand Down
18 changes: 12 additions & 6 deletions crates/bitcoind_rpc/tests/test_emitter.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -198,12 +198,15 @@ pub fn test_sync_local_chain() -> anyhow::Result<()> {
}

assert_eq!(
local_chain.blocks(),
&exp_hashes
local_chain
.iter_checkpoints()
.map(|cp| (cp.height(), cp.hash()))
.collect::<Vec<_>>(),
exp_hashes
.iter()
.enumerate()
.map(|(i, hash)| (i as u32, *hash))
.collect(),
.collect::<Vec<_>>(),
"final local_chain state is unexpected",
);

Expand Down Expand Up @@ -251,12 +254,15 @@ pub fn test_sync_local_chain() -> anyhow::Result<()> {
}

assert_eq!(
local_chain.blocks(),
&exp_hashes
local_chain
.iter_checkpoints()
.map(|cp| (cp.height(), cp.hash()))
.collect::<Vec<_>>(),
exp_hashes
.iter()
.enumerate()
.map(|(i, hash)| (i as u32, *hash))
.collect(),
.collect::<Vec<_>>(),
"final local_chain state is unexpected after reorg",
);

Expand Down
193 changes: 98 additions & 95 deletions crates/chain/src/local_chain.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -4,8 +4,8 @@ use core::convert::Infallible;

use crate::collections::BTreeMap;
use crate::{BlockId, ChainOracle};
use alloc::collections::BTreeSet;
use alloc::sync::Arc;
use alloc::vec::Vec;
use bitcoin::block::Header;
use bitcoin::BlockHash;

Expand Down Expand Up @@ -150,33 +150,21 @@ impl CheckPoint {
self.clone().into_iter()
}

/// Find checkpoint at `height`.
/// Query for checkpoint at `height`.
///
/// Returns `None` if checkpoint at `height` does not exist`. If you are querying for multiple
/// heights, it will be more efficient to use [`query_multi`].
///
/// [`query_multi`]: CheckPoint::query_multi
/// Returns `None` if checkpoint at `height` does not exist`.
pub fn query(&self, height: u32) -> Option<Self> {
self.iter()
// optimization to avoid iterating the entire chain if we do not get a direct hit
.take_while(|cp| cp.height() >= height)
.find(|cp| cp.height() == height)
}

/// Find checkpoints of the given `heights`.
/// Query for checkpoint that is greater or equal to `height`.
///
/// This returns an iterator which iterates over the requested heights and whether a
/// corresponding checkpoint is found.
pub fn query_multi(&self, heights: BTreeSet<u32>) -> impl Iterator<Item = (u32, Option<Self>)> {
let mut cp_iter = self.iter();
let mut current_cp = cp_iter.next();
heights.into_iter().rev().map(move |h| loop {
match current_cp.as_ref() {
Some(cp) if cp.height() > h => current_cp = cp_iter.next(),
Some(cp) if cp.height() == h => return (h, Some(cp.clone())),
_ => return (h, None),
}
})
/// Returns `None` if no checkpoints has a height equal or greater than `height`.
pub fn query_from(&self, height: u32) -> Option<Self> {
self.iter().take_while(|cp| cp.height() >= height).last()
}
}

Expand Down Expand Up @@ -235,18 +223,28 @@ pub struct Update {
#[derive(Debug, Clone)]
pub struct LocalChain {
tip: CheckPoint,
index: BTreeMap<u32, BlockHash>,
}

impl PartialEq for LocalChain {
fn eq(&self, other: &Self) -> bool {
self.index == other.index
self.iter_checkpoints()
.map(|cp| cp.block_id())
.collect::<Vec<_>>()
== other
.iter_checkpoints()
.map(|cp| cp.block_id())
.collect::<Vec<_>>()
}
}

// TODO: Figure out whether we can get rid of this
impl From<LocalChain> for BTreeMap<u32, BlockHash> {
fn from(value: LocalChain) -> Self {
value.index
value
.tip
.iter()
.map(|cp| (cp.height(), cp.hash()))
.collect()
}
}

Expand All @@ -258,18 +256,16 @@ impl ChainOracle for LocalChain {
block: BlockId,
chain_tip: BlockId,
) -> Result<Option<bool>, Self::Error> {
if block.height > chain_tip.height {
return Ok(None);
let chain_tip_cp = match self.tip.query(chain_tip.height) {
// we can only determine whether `block` is in chain of `chain_tip` if `chain_tip` can
// be identified in chain
Some(cp) if cp.hash() == chain_tip.hash => cp,
_ => return Ok(None),
};
match chain_tip_cp.query(block.height) {
Some(cp) => Ok(Some(cp.hash() == block.hash)),
None => Ok(None),
}
Ok(
match (
self.index.get(&block.height),
self.index.get(&chain_tip.height),
) {
(Some(cp), Some(tip_cp)) => Some(*cp == block.hash && *tip_cp == chain_tip.hash),
_ => None,
},
)
}

fn get_chain_tip(&self) -> Result<BlockId, Self::Error> {
Expand All @@ -280,7 +276,7 @@ impl ChainOracle for LocalChain {
impl LocalChain {
/// Get the genesis hash.
pub fn genesis_hash(&self) -> BlockHash {
self.index.get(&0).copied().expect("must have genesis hash")
self.tip.query(0).expect("genesis must exist").hash()
}

/// Construct [`LocalChain`] from genesis `hash`.
Expand All @@ -289,7 +285,6 @@ impl LocalChain {
let height = 0;
let chain = Self {
tip: CheckPoint::new(BlockId { height, hash }),
index: core::iter::once((height, hash)).collect(),
};
let changeset = chain.initial_changeset();
(chain, changeset)
Expand All @@ -306,39 +301,30 @@ impl LocalChain {
let (mut chain, _) = Self::from_genesis_hash(genesis_hash);
chain.apply_changeset(&changeset)?;

debug_assert!(chain._check_index_is_consistent_with_tip());
debug_assert!(chain._check_changeset_is_applied(&changeset));

Ok(chain)
}

/// Construct a [`LocalChain`] from a given `checkpoint` tip.
pub fn from_tip(tip: CheckPoint) -> Result<Self, MissingGenesisError> {
let mut chain = Self {
tip,
index: BTreeMap::new(),
};
chain.reindex(0);

if chain.index.get(&0).copied().is_none() {
let genesis_cp = tip.iter().last().expect("must have at least one element");
if genesis_cp.height() != 0 {
return Err(MissingGenesisError);
}

debug_assert!(chain._check_index_is_consistent_with_tip());
Ok(chain)
Ok(Self { tip })
}

/// Constructs a [`LocalChain`] from a [`BTreeMap`] of height to [`BlockHash`].
///
/// The [`BTreeMap`] enforces the height order. However, the caller must ensure the blocks are
/// all of the same chain.
pub fn from_blocks(blocks: BTreeMap<u32, BlockHash>) -> Result<Self, MissingGenesisError> {
if !blocks.contains_key(&0) {
if blocks.get(&0).is_none() {
return Err(MissingGenesisError);
}

let mut tip: Option<CheckPoint> = None;

for block in &blocks {
match tip {
Some(curr) => {
Expand All @@ -351,13 +337,9 @@ impl LocalChain {
}
}

let chain = Self {
index: blocks,
Ok(Self {
tip: tip.expect("already checked to have genesis"),
};

debug_assert!(chain._check_index_is_consistent_with_tip());
Ok(chain)
})
}

/// Get the highest checkpoint.
Expand Down Expand Up @@ -524,9 +506,7 @@ impl LocalChain {
None => LocalChain::from_blocks(extension)?.tip(),
};
self.tip = new_tip;
self.reindex(start_height);

debug_assert!(self._check_index_is_consistent_with_tip());
debug_assert!(self._check_changeset_is_applied(changeset));
}

Expand All @@ -539,16 +519,16 @@ impl LocalChain {
///
/// Replacing the block hash of an existing checkpoint will result in an error.
pub fn insert_block(&mut self, block_id: BlockId) -> Result<ChangeSet, AlterCheckPointError> {
if let Some(&original_hash) = self.index.get(&block_id.height) {
if let Some(original_cp) = self.tip.query(block_id.height) {
let original_hash = original_cp.hash();
if original_hash != block_id.hash {
return Err(AlterCheckPointError {
height: block_id.height,
original_hash,
update_hash: Some(block_id.hash),
});
} else {
return Ok(ChangeSet::default());
}
return Ok(ChangeSet::default());
}

let mut changeset = ChangeSet::default();
Expand All @@ -572,33 +552,41 @@ impl LocalChain {
/// This will fail with [`MissingGenesisError`] if the caller attempts to disconnect from the
/// genesis block.
pub fn disconnect_from(&mut self, block_id: BlockId) -> Result<ChangeSet, MissingGenesisError> {
if self.index.get(&block_id.height) != Some(&block_id.hash) {
return Ok(ChangeSet::default());
}

let changeset = self
.index
.range(block_id.height..)
.map(|(&height, _)| (height, None))
.collect::<ChangeSet>();
self.apply_changeset(&changeset).map(|_| changeset)
}

/// Reindex the heights in the chain from (and including) `from` height
fn reindex(&mut self, from: u32) {
let _ = self.index.split_off(&from);
for cp in self.iter_checkpoints() {
if cp.height() < from {
let mut remove_from = Option::<CheckPoint>::None;
let mut changeset = ChangeSet::default();
for cp in self.tip().iter() {
let cp_id = cp.block_id();
if cp_id.height < block_id.height {
break;
}
self.index.insert(cp.height(), cp.hash());
changeset.insert(cp_id.height, None);
if cp_id == block_id {
remove_from = Some(cp);
}
}
self.tip = match remove_from.map(|cp| cp.prev()) {
// The checkpoint below the earliest checkpoint to remove will be the new tip.
Some(Some(new_tip)) => new_tip,
// If there is no checkpoint below the earliest checkpoint to remove, it means the
// "earliest checkpoint to remove" is the genesis block. We disallow removing the
// genesis block.
Some(None) => return Err(MissingGenesisError),
// If there is nothing to remove, we return an empty changeset.
None => return Ok(ChangeSet::default()),
};
Ok(changeset)
}

/// Derives an initial [`ChangeSet`], meaning that it can be applied to an empty chain to
/// recover the current chain.
pub fn initial_changeset(&self) -> ChangeSet {
self.index.iter().map(|(k, v)| (*k, Some(*v))).collect()
self.tip
.iter()
.map(|cp| {
let block_id = cp.block_id();
(block_id.height, Some(block_id.hash))
})
.collect()
}

/// Iterate over checkpoints in descending height order.
Expand All @@ -608,28 +596,43 @@ impl LocalChain {
}
}

/// Get a reference to the internal index mapping the height to block hash.
pub fn blocks(&self) -> &BTreeMap<u32, BlockHash> {
&self.index
}

fn _check_index_is_consistent_with_tip(&self) -> bool {
let tip_history = self
.tip
.iter()
.map(|cp| (cp.height(), cp.hash()))
.collect::<BTreeMap<_, _>>();
self.index == tip_history
}

fn _check_changeset_is_applied(&self, changeset: &ChangeSet) -> bool {
for (height, exp_hash) in changeset {
if self.index.get(height) != exp_hash.as_ref() {
return false;
let mut curr_cp = self.tip.clone();
for (height, exp_hash) in changeset.iter().rev() {
match curr_cp.query(*height) {
Some(query_cp) => {
if query_cp.height() != *height || Some(query_cp.hash()) != *exp_hash {
return false;
}
curr_cp = query_cp;
}
None => {
if exp_hash.is_some() {
return false;
}
}
}
}
true
}

/// Query for checkpoint at given `height` (if it exists).
///
/// This is a shorthand for calling [`CheckPoint::query`] on the [`tip`].
///
/// [`tip`]: LocalChain::tip
pub fn query(&self, height: u32) -> Option<CheckPoint> {
self.tip.query(height)
}

/// Query for checkpoint that is greater or equal to `height`.
///
/// This is a shorthand for calling [`CheckPoint::query_from`] on the [`tip`].
///
/// [`tip`]: LocalChain::tip
pub fn query_from(&self, height: u32) -> Option<CheckPoint> {
self.tip.query_from(height)
}
}

/// An error which occurs when a [`LocalChain`] is constructed without a genesis checkpoint.
Expand Down
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