[bdk_chain_redesign] Initial work on LocalChain.

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志宇 2023-03-29 22:45:01 +08:00
parent 34d0277e44
commit 468701a129
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GPG Key ID: F6345C9837C2BDE8
5 changed files with 150 additions and 1 deletions

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@ -11,6 +11,7 @@ pub enum ObservedIn<A> {
/// The chain data is seen in a block identified by `A`.
Block(A),
/// The chain data is seen in mempool at this given timestamp.
/// TODO: Call this `Unconfirmed`.
Mempool(u64),
}

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@ -68,7 +68,7 @@ impl<A: BlockAnchor, D: TxIndexAdditions> TxIndexAdditions for IndexedAdditions<
pub struct IndexedTxGraph<A, I> {
graph: TxGraph<A>,
index: I,
index: I, // [TODO] Make public
last_height: u32,
}
@ -219,6 +219,7 @@ impl<A: BlockAnchor, I: TxIndex> IndexedTxGraph<A, I> {
self.last_height
}
// [TODO] Have to methods, one for relevant-only, and one for any. Have one in `TxGraph`.
pub fn try_list_chain_txs<'a, C>(
&'a self,
chain: C,

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@ -26,6 +26,7 @@ mod chain_data;
pub use chain_data::*;
pub mod indexed_tx_graph;
pub mod keychain;
pub mod local_chain;
pub mod sparse_chain;
mod tx_data_traits;
pub mod tx_graph;

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@ -0,0 +1,140 @@
use core::convert::Infallible;
use alloc::{collections::BTreeMap, vec::Vec};
use bitcoin::BlockHash;
use crate::{BlockId, ChainOracle};
#[derive(Debug, Default, Clone, PartialEq, Eq, PartialOrd, Ord)]
pub struct LocalChain {
blocks: BTreeMap<u32, BlockHash>,
}
// [TODO] We need a cache/snapshot thing for chain oracle.
// * Minimize calls to remotes.
// * Can we cache it forever? Should we drop stuff?
// * Assume anything deeper than (i.e. 10) blocks won't be reorged.
// * Is this a cache on txs or block? or both?
// [TODO] Parents of children are confirmed if children are confirmed.
impl ChainOracle for LocalChain {
type Error = Infallible;
fn get_block_in_best_chain(&self, height: u32) -> Result<Option<BlockHash>, Self::Error> {
Ok(self.blocks.get(&height).cloned())
}
}
impl AsRef<BTreeMap<u32, BlockHash>> for LocalChain {
fn as_ref(&self) -> &BTreeMap<u32, BlockHash> {
&self.blocks
}
}
impl From<LocalChain> for BTreeMap<u32, BlockHash> {
fn from(value: LocalChain) -> Self {
value.blocks
}
}
impl LocalChain {
pub fn tip(&self) -> Option<BlockId> {
self.blocks
.iter()
.last()
.map(|(&height, &hash)| BlockId { height, hash })
}
/// This is like the sparsechain's logic, expect we must guarantee that all invalidated heights
/// are to be re-filled.
pub fn determine_changeset<U>(&self, update: &U) -> Result<ChangeSet, UpdateError>
where
U: AsRef<BTreeMap<u32, BlockHash>>,
{
let update = update.as_ref();
let update_tip = match update.keys().last().cloned() {
Some(tip) => tip,
None => return Ok(ChangeSet::default()),
};
// this is the latest height where both the update and local chain has the same block hash
let agreement_height = update
.iter()
.rev()
.find(|&(u_height, u_hash)| self.blocks.get(u_height) == Some(u_hash))
.map(|(&height, _)| height);
// the lower bound of the range to invalidate
let invalidate_lb = match agreement_height {
Some(height) if height == update_tip => u32::MAX,
Some(height) => height + 1,
None => 0,
};
// the first block's height to invalidate in the local chain
let invalidate_from = self.blocks.range(invalidate_lb..).next().map(|(&h, _)| h);
// the first block of height to invalidate (if any) should be represented in the update
if let Some(first_invalid) = invalidate_from {
if !update.contains_key(&first_invalid) {
return Err(UpdateError::NotConnected(first_invalid));
}
}
let invalidated_heights = invalidate_from
.into_iter()
.flat_map(|from_height| self.blocks.range(from_height..).map(|(h, _)| h));
// invalidated heights must all exist in the update
let mut missing_heights = Vec::<u32>::new();
for invalidated_height in invalidated_heights {
if !update.contains_key(invalidated_height) {
missing_heights.push(*invalidated_height);
}
}
if !missing_heights.is_empty() {
return Err(UpdateError::MissingHeightsInUpdate(missing_heights));
}
let mut changeset = BTreeMap::<u32, BlockHash>::new();
for (height, new_hash) in update {
let original_hash = self.blocks.get(height);
if Some(new_hash) != original_hash {
changeset.insert(*height, *new_hash);
}
}
Ok(ChangeSet(changeset))
}
}
#[derive(Debug, Default)]
pub struct ChangeSet(pub BTreeMap<u32, BlockHash>);
/// Represents an update failure of [`LocalChain`].j
#[derive(Clone, Debug, PartialEq)]
pub enum UpdateError {
/// The update cannot be applied to the chain because the chain suffix it represents did not
/// connect to the existing chain. This error case contains the checkpoint height to include so
/// that the chains can connect.
NotConnected(u32),
/// If the update results in displacements of original blocks, the update should include all new
/// block hashes that have displaced the original block hashes. This error case contains the
/// heights of all missing block hashes in the update.
MissingHeightsInUpdate(Vec<u32>),
}
impl core::fmt::Display for UpdateError {
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
match self {
UpdateError::NotConnected(heights) => write!(
f,
"the update cannot connect with the chain, try include blockhash at height {}",
heights
),
UpdateError::MissingHeightsInUpdate(missing_heights) => write!(
f,
"block hashes of these heights must be included in the update to succeed: {:?}",
missing_heights
),
}
}
}

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@ -58,6 +58,10 @@ impl BlockAnchor for (u32, BlockHash) {
}
/// Represents a service that tracks the best chain history.
/// TODO: How do we ensure the chain oracle is consistent across a single call?
/// * We need to somehow lock the data! What if the ChainOracle is remote?
/// * Get tip method! And check the tip still exists at the end! And every internal call
/// does not go beyond the initial tip.
pub trait ChainOracle {
/// Error type.
type Error: core::fmt::Debug;
@ -71,6 +75,8 @@ pub trait ChainOracle {
}
}
// [TODO] We need stuff for smart pointers. Maybe? How does rust lib do this?
// Box<dyn ChainOracle>, Arc<dyn ChainOracle> ????? I will figure it out
impl<C: ChainOracle> ChainOracle for &C {
type Error = C::Error;