10505233318

Committed 22 Aug 2024 09:12AM UTC coverage: 81.812% (-0.04%) from 81.848%

Build # 10505233318

Build Type

Pull #1566

github

Committed by

web-flow

Commit Message

Merge 9b75eebe4 into 6008897aa

Pull Request Pull Request #1566: feat(chain)!: Add `time_of_sync` to `SyncRequest` and `FullScanRequest` WIP

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/crates/electrum/src/bdk_electrum_client.rs

use bdk_chain::{
    bitcoin::{block::Header, BlockHash, OutPoint, ScriptBuf, Transaction, Txid},
    collections::{BTreeMap, HashMap},
    local_chain::CheckPoint,
    spk_client::{FullScanRequest, FullScanResult, SyncRequest, SyncResult},
    tx_graph::TxGraph,
    Anchor, BlockId, ConfirmationBlockTime,
};
use electrum_client::{ElectrumApi, Error, HeaderNotification};
use std::{
    collections::BTreeSet,
    sync::{Arc, Mutex},
};

/// We include a chain suffix of a certain length for the purpose of robustness.
const CHAIN_SUFFIX_LENGTH: u32 = 8;

/// Wrapper around an [`electrum_client::ElectrumApi`] which includes an internal in-memory
/// transaction cache to avoid re-fetching already downloaded transactions.
#[derive(Debug)]
pub struct BdkElectrumClient<E> {
    /// The internal [`electrum_client::ElectrumApi`]
    pub inner: E,
    /// The transaction cache
    tx_cache: Mutex<HashMap<Txid, Arc<Transaction>>>,
    /// The header cache
    block_header_cache: Mutex<HashMap<u32, Header>>,
}

impl<E: ElectrumApi> BdkElectrumClient<E> {
    /// Creates a new bdk client from a [`electrum_client::ElectrumApi`]
    pub fn new(client: E) -> Self {
        Self {
            inner: client,
            tx_cache: Default::default(),
            block_header_cache: Default::default(),
        }
    }

    /// Inserts transactions into the transaction cache so that the client will not fetch these
    /// transactions.
    pub fn populate_tx_cache<A>(&self, tx_graph: impl AsRef<TxGraph<A>>) {
        let txs = tx_graph
            .as_ref()
            .full_txs()
            .map(|tx_node| (tx_node.txid, tx_node.tx));

        let mut tx_cache = self.tx_cache.lock().unwrap();
        for (txid, tx) in txs {
            tx_cache.insert(txid, tx);
        }
    }

    /// Fetch transaction of given `txid`.
    ///
    /// If it hits the cache it will return the cached version and avoid making the request.
    pub fn fetch_tx(&self, txid: Txid) -> Result<Arc<Transaction>, Error> {
        let tx_cache = self.tx_cache.lock().unwrap();

        if let Some(tx) = tx_cache.get(&txid) {
            return Ok(Arc::clone(tx));
        }

        drop(tx_cache);

        let tx = Arc::new(self.inner.transaction_get(&txid)?);

        self.tx_cache.lock().unwrap().insert(txid, Arc::clone(&tx));

        Ok(tx)
    }

    /// Fetch block header of given `height`.
    ///
    /// If it hits the cache it will return the cached version and avoid making the request.
    fn fetch_header(&self, height: u32) -> Result<Header, Error> {
        let block_header_cache = self.block_header_cache.lock().unwrap();

        if let Some(header) = block_header_cache.get(&height) {
            return Ok(*header);
        }

        drop(block_header_cache);

        self.update_header(height)
    }

    /// Update a block header at given `height`. Returns the updated header.
    fn update_header(&self, height: u32) -> Result<Header, Error> {
        let header = self.inner.block_header(height as usize)?;

        self.block_header_cache
            .lock()
            .unwrap()
            .insert(height, header);

        Ok(header)
    }

    /// Broadcasts a transaction to the network.
    ///
    /// This is a re-export of [`ElectrumApi::transaction_broadcast`].
    pub fn transaction_broadcast(&self, tx: &Transaction) -> Result<Txid, Error> {
        self.inner.transaction_broadcast(tx)
    }

    /// Full scan the keychain scripts specified with the blockchain (via an Electrum client) and
    /// returns updates for [`bdk_chain`] data structures.
    ///
    /// - `request`: struct with data required to perform a spk-based blockchain client full scan,
    ///              see [`FullScanRequest`].
    /// - `stop_gap`: the full scan for each keychain stops after a gap of script pubkeys with no
    ///               associated transactions.
    /// - `batch_size`: specifies the max number of script pubkeys to request for in a single batch
    ///                 request.
    /// - `fetch_prev_txouts`: specifies whether we want previous `TxOut`s for fee calculation.
    ///                        Note that this requires additional calls to the Electrum server, but
    ///                        is necessary for calculating the fee on a transaction if your wallet
    ///                        does not own the inputs. Methods like [`Wallet.calculate_fee`] and
    ///                        [`Wallet.calculate_fee_rate`] will return a
    ///                        [`CalculateFeeError::MissingTxOut`] error if those `TxOut`s are not
    ///                        present in the transaction graph.
    ///
    /// [`CalculateFeeError::MissingTxOut`]: bdk_chain::tx_graph::CalculateFeeError::MissingTxOut
    /// [`Wallet.calculate_fee`]: https://docs.rs/bdk_wallet/latest/bdk_wallet/struct.Wallet.html#method.calculate_fee
    /// [`Wallet.calculate_fee_rate`]: https://docs.rs/bdk_wallet/latest/bdk_wallet/struct.Wallet.html#method.calculate_fee_rate
    pub fn full_scan<K: Ord + Clone>(
        &self,
        request: impl Into<FullScanRequest<K>>,
        stop_gap: usize,
        batch_size: usize,
        fetch_prev_txouts: bool,
    ) -> Result<FullScanResult<K>, Error> {
        let mut request: FullScanRequest<K> = request.into();

        let tip_and_latest_blocks = match request.chain_tip() {
            Some(chain_tip) => Some(fetch_tip_and_latest_blocks(&self.inner, chain_tip)?),
            None => None,
        };
        let time_of_sync = request.get_time_of_sync();

        let mut graph_update = TxGraph::<ConfirmationBlockTime>::default();
        let mut last_active_indices = BTreeMap::<K, u32>::default();
        for keychain in request.keychains() {
            let spks = request.iter_spks(keychain.clone());
            if let Some(last_active_index) = self.populate_with_spks(
                &mut graph_update,
                spks,
                stop_gap,
                batch_size,
                time_of_sync,
            )? {
                last_active_indices.insert(keychain, last_active_index);
            }
        }

        // Fetch previous `TxOut`s for fee calculation if flag is enabled.
        if fetch_prev_txouts {
            self.fetch_prev_txout(&mut graph_update)?;
        }

        let chain_update = match tip_and_latest_blocks {
            Some((chain_tip, latest_blocks)) => Some(chain_update(
                chain_tip,
                &latest_blocks,
                graph_update.all_anchors(),
            )?),
            _ => None,
        };

        Ok(FullScanResult {
            graph_update,
            chain_update,
            last_active_indices,
        })
    }

    /// Sync a set of scripts with the blockchain (via an Electrum client) for the data specified
    /// and returns updates for [`bdk_chain`] data structures.
    ///
    /// - `request`: struct with data required to perform a spk-based blockchain client sync,
    ///              see [`SyncRequest`]
    /// - `batch_size`: specifies the max number of script pubkeys to request for in a single batch
    ///                 request
    /// - `fetch_prev_txouts`: specifies whether we want previous `TxOut`s for fee calculation.
    ///                        Note that this requires additional calls to the Electrum server, but
    ///                        is necessary for calculating the fee on a transaction if your wallet
    ///                        does not own the inputs. Methods like [`Wallet.calculate_fee`] and
    ///                        [`Wallet.calculate_fee_rate`] will return a
    ///                        [`CalculateFeeError::MissingTxOut`] error if those `TxOut`s are not
    ///                        present in the transaction graph.
    ///
    /// If the scripts to sync are unknown, such as when restoring or importing a keychain that
    /// may include scripts that have been used, use [`full_scan`] with the keychain.
    ///
    /// [`full_scan`]: Self::full_scan
    /// [`CalculateFeeError::MissingTxOut`]: bdk_chain::tx_graph::CalculateFeeError::MissingTxOut
    /// [`Wallet.calculate_fee`]: https://docs.rs/bdk_wallet/latest/bdk_wallet/struct.Wallet.html#method.calculate_fee
    /// [`Wallet.calculate_fee_rate`]: https://docs.rs/bdk_wallet/latest/bdk_wallet/struct.Wallet.html#method.calculate_fee_rate
    pub fn sync<I: 'static>(
        &self,
        request: impl Into<SyncRequest<I>>,
        batch_size: usize,
        fetch_prev_txouts: bool,
    ) -> Result<SyncResult, Error> {
        let mut request: SyncRequest<I> = request.into();

        let tip_and_latest_blocks = match request.chain_tip() {
            Some(chain_tip) => Some(fetch_tip_and_latest_blocks(&self.inner, chain_tip)?),
            None => None,
        };
        let time_of_sync = request.get_time_of_sync();

        let mut graph_update = TxGraph::<ConfirmationBlockTime>::default();
        self.populate_with_spks(
            &mut graph_update,
            request
                .iter_spks()
                .enumerate()
                .map(|(i, spk)| (i as u32, spk)),
            usize::MAX,
            batch_size,
            time_of_sync,
        )?;
        self.populate_with_txids(&mut graph_update, request.iter_txids(), time_of_sync)?;
        self.populate_with_outpoints(&mut graph_update, request.iter_outpoints(), time_of_sync)?;

        // Fetch previous `TxOut`s for fee calculation if flag is enabled.
        if fetch_prev_txouts {
            self.fetch_prev_txout(&mut graph_update)?;
        }

        let chain_update = match tip_and_latest_blocks {
            Some((chain_tip, latest_blocks)) => Some(chain_update(
                chain_tip,
                &latest_blocks,
                graph_update.all_anchors(),
            )?),
            None => None,
        };

        Ok(SyncResult {
            graph_update,
            chain_update,
        })
    }

    /// Populate the `graph_update` with transactions/anchors associated with the given `spks`.
    ///
    /// Transactions that contains an output with requested spk, or spends form an output with
    /// requested spk will be added to `graph_update`. Anchors of the aforementioned transactions are
    /// also included.
    fn populate_with_spks(
        &self,
        graph_update: &mut TxGraph<ConfirmationBlockTime>,
        mut spks: impl Iterator<Item = (u32, ScriptBuf)>,
        stop_gap: usize,
        batch_size: usize,
        time_of_sync: Option<u64>,
    ) -> Result<Option<u32>, Error> {
        let mut unused_spk_count = 0_usize;
        let mut last_active_index = Option::<u32>::None;

        loop {
            let spks = (0..batch_size)
                .map_while(|_| spks.next())
                .collect::<Vec<_>>();
            if spks.is_empty() {
                return Ok(last_active_index);
            }

            let spk_histories = self
                .inner
                .batch_script_get_history(spks.iter().map(|(_, s)| s.as_script()))?;

            for ((spk_index, _spk), spk_history) in spks.into_iter().zip(spk_histories) {
                if spk_history.is_empty() {
                    unused_spk_count = unused_spk_count.saturating_add(1);
                    if unused_spk_count >= stop_gap {
                        return Ok(last_active_index);
                    }
                    continue;
                } else {
                    last_active_index = Some(spk_index);
                    unused_spk_count = 0;
                }

                for tx_res in spk_history {
                    let _ = graph_update.insert_tx(self.fetch_tx(tx_res.tx_hash)?);
                    self.validate_merkle_for_anchor(
                        graph_update,
                        tx_res.tx_hash,
                        tx_res.height,
                        time_of_sync,
                    )?;
                }
            }
        }
    }

    /// Populate the `graph_update` with associated transactions/anchors of `outpoints`.
    ///
    /// Transactions in which the outpoint resides, and transactions that spend from the outpoint are
    /// included. Anchors of the aforementioned transactions are included.
    fn populate_with_outpoints(
        &self,
        graph_update: &mut TxGraph<ConfirmationBlockTime>,
        outpoints: impl IntoIterator<Item = OutPoint>,
        time_of_sync: Option<u64>,
    ) -> Result<(), Error> {
        for outpoint in outpoints {
            let op_txid = outpoint.txid;
            let op_tx = self.fetch_tx(op_txid)?;
            let op_txout = match op_tx.output.get(outpoint.vout as usize) {
                Some(txout) => txout,
                None => continue,
            };
            debug_assert_eq!(op_tx.compute_txid(), op_txid);

            // attempt to find the following transactions (alongside their chain positions), and
            // add to our sparsechain `update`:
            let mut has_residing = false; // tx in which the outpoint resides
            let mut has_spending = false; // tx that spends the outpoint
            for res in self.inner.script_get_history(&op_txout.script_pubkey)? {
                if has_residing && has_spending {
                    break;
                }

                if !has_residing && res.tx_hash == op_txid {
                    has_residing = true;
                    let _ = graph_update.insert_tx(Arc::clone(&op_tx));
                    self.validate_merkle_for_anchor(
                        graph_update,
                        res.tx_hash,
                        res.height,
                        time_of_sync,
                    )?;
                }

                if !has_spending && res.tx_hash != op_txid {
                    let res_tx = self.fetch_tx(res.tx_hash)?;
                    // we exclude txs/anchors that do not spend our specified outpoint(s)
                    has_spending = res_tx
                        .input
                        .iter()
                        .any(|txin| txin.previous_output == outpoint);
                    if !has_spending {
                        continue;
                    }
                    let _ = graph_update.insert_tx(Arc::clone(&res_tx));
                    self.validate_merkle_for_anchor(
                        graph_update,
                        res.tx_hash,
                        res.height,
                        time_of_sync,
                    )?;
                }
            }
        }
        Ok(())
    }

    /// Populate the `graph_update` with transactions/anchors of the provided `txids`.
    fn populate_with_txids(
        &self,
        graph_update: &mut TxGraph<ConfirmationBlockTime>,
        txids: impl IntoIterator<Item = Txid>,
        time_of_sync: Option<u64>,
    ) -> Result<(), Error> {
        for txid in txids {
            let tx = match self.fetch_tx(txid) {
                Ok(tx) => tx,
                Err(electrum_client::Error::Protocol(_)) => continue,
                Err(other_err) => return Err(other_err),
            };

            let spk = tx
                .output
                .first()
                .map(|txo| &txo.script_pubkey)
                .expect("tx must have an output");

            // because of restrictions of the Electrum API, we have to use the `script_get_history`
            // call to get confirmation status of our transaction
            if let Some(r) = self
                .inner
                .script_get_history(spk)?
                .into_iter()
                .find(|r| r.tx_hash == txid)
            {
                self.validate_merkle_for_anchor(graph_update, txid, r.height, time_of_sync)?;
            }

            let _ = graph_update.insert_tx(tx);
        }
        Ok(())
    }

    // Helper function which checks if a transaction is confirmed by validating the merkle proof.
    // An anchor is inserted if the transaction is validated to be in a confirmed block.
    fn validate_merkle_for_anchor(
        &self,
        graph_update: &mut TxGraph<ConfirmationBlockTime>,
        txid: Txid,
        confirmation_height: i32,
        time_of_sync: Option<u64>,
    ) -> Result<(), Error> {
        if let Ok(merkle_res) = self
            .inner
            .transaction_get_merkle(&txid, confirmation_height as usize)
        {
            let mut header = self.fetch_header(merkle_res.block_height as u32)?;
            let mut is_confirmed_tx = electrum_client::utils::validate_merkle_proof(
                &txid,
                &header.merkle_root,
                &merkle_res,
            );

            // Merkle validation will fail if the header in `block_header_cache` is outdated, so we
            // want to check if there is a new header and validate against the new one.
            if !is_confirmed_tx {
                header = self.update_header(merkle_res.block_height as u32)?;
                is_confirmed_tx = electrum_client::utils::validate_merkle_proof(
                    &txid,
                    &header.merkle_root,
                    &merkle_res,
                );
            }

            if is_confirmed_tx {
                let _ = graph_update.insert_anchor(
                    txid,
                    ConfirmationBlockTime {
                        confirmation_time: header.time as u64,
                        block_id: BlockId {
                            height: merkle_res.block_height as u32,
                            hash: header.block_hash(),
                        },
                    },
                );
            }
        } else {
            // If no merkle proof is returned, then the tx is unconfirmed and we set the last_seen.
            if let Some(seen_at) = time_of_sync {
                let _ = graph_update.insert_seen_at(txid, seen_at);
            }
        }
        Ok(())
    }

    // Helper function which fetches the `TxOut`s of our relevant transactions' previous transactions,
    // which we do not have by default. This data is needed to calculate the transaction fee.
    fn fetch_prev_txout(
        &self,
        graph_update: &mut TxGraph<ConfirmationBlockTime>,
    ) -> Result<(), Error> {
        let full_txs: Vec<Arc<Transaction>> =
            graph_update.full_txs().map(|tx_node| tx_node.tx).collect();
        for tx in full_txs {
            for vin in &tx.input {
                let outpoint = vin.previous_output;
                let vout = outpoint.vout;
                let prev_tx = self.fetch_tx(outpoint.txid)?;
                let txout = prev_tx.output[vout as usize].clone();
                let _ = graph_update.insert_txout(outpoint, txout);
            }
        }
        Ok(())
    }
}

/// Return a [`CheckPoint`] of the latest tip, that connects with `prev_tip`. The latest blocks are
/// fetched to construct checkpoint updates with the proper [`BlockHash`] in case of re-org.
fn fetch_tip_and_latest_blocks(
    client: &impl ElectrumApi,
    prev_tip: CheckPoint,
) -> Result<(CheckPoint, BTreeMap<u32, BlockHash>), Error> {
    let HeaderNotification { height, .. } = client.block_headers_subscribe()?;
    let new_tip_height = height as u32;

    // If electrum returns a tip height that is lower than our previous tip, then checkpoints do
    // not need updating. We just return the previous tip and use that as the point of agreement.
    if new_tip_height < prev_tip.height() {
        return Ok((prev_tip, BTreeMap::new()));
    }

    // Atomically fetch the latest `CHAIN_SUFFIX_LENGTH` count of blocks from Electrum. We use this
    // to construct our checkpoint update.
    let mut new_blocks = {
        let start_height = new_tip_height.saturating_sub(CHAIN_SUFFIX_LENGTH - 1);
        let hashes = client
            .block_headers(start_height as _, CHAIN_SUFFIX_LENGTH as _)?
            .headers
            .into_iter()
            .map(|h| h.block_hash());
        (start_height..).zip(hashes).collect::<BTreeMap<u32, _>>()
    };

    // Find the "point of agreement" (if any).
    let agreement_cp = {
        let mut agreement_cp = Option::<CheckPoint>::None;
        for cp in prev_tip.iter() {
            let cp_block = cp.block_id();
            let hash = match new_blocks.get(&cp_block.height) {
                Some(&hash) => hash,
                None => {
                    assert!(
                        new_tip_height >= cp_block.height,
                        "already checked that electrum's tip cannot be smaller"
                    );
                    let hash = client.block_header(cp_block.height as _)?.block_hash();
                    new_blocks.insert(cp_block.height, hash);
                    hash
                }
            };
            if hash == cp_block.hash {
                agreement_cp = Some(cp);
                break;
            }
        }
        agreement_cp
    };

    let agreement_height = agreement_cp.as_ref().map(CheckPoint::height);

    let new_tip = new_blocks
        .iter()
        // Prune `new_blocks` to only include blocks that are actually new.
        .filter(|(height, _)| Some(*<&u32>::clone(height)) > agreement_height)
        .map(|(height, hash)| BlockId {
            height: *height,
            hash: *hash,
        })
        .fold(agreement_cp, |prev_cp, block| {
            Some(match prev_cp {
                Some(cp) => cp.push(block).expect("must extend checkpoint"),
                None => CheckPoint::new(block),
            })
        })
        .expect("must have at least one checkpoint");

    Ok((new_tip, new_blocks))
}

// Add a corresponding checkpoint per anchor height if it does not yet exist. Checkpoints should not
// surpass `latest_blocks`.
fn chain_update<A: Anchor>(
    mut tip: CheckPoint,
    latest_blocks: &BTreeMap<u32, BlockHash>,
    anchors: &BTreeSet<(A, Txid)>,
) -> Result<CheckPoint, Error> {
    for anchor in anchors {
        let height = anchor.0.anchor_block().height;

        // Checkpoint uses the `BlockHash` from `latest_blocks` so that the hash will be consistent
        // in case of a re-org.
        if tip.get(height).is_none() && height <= tip.height() {
            let hash = match latest_blocks.get(&height) {
                Some(&hash) => hash,
                None => anchor.0.anchor_block().hash,
            };
            tip = tip.insert(BlockId { hash, height });
        }
    }
    Ok(tip)
}

1	use bdk_chain::{
2	bitcoin::{block::Header, BlockHash, OutPoint, ScriptBuf, Transaction, Txid},
3	collections::{BTreeMap, HashMap},
4	local_chain::CheckPoint,
5	spk_client::{FullScanRequest, FullScanResult, SyncRequest, SyncResult},
6	tx_graph::TxGraph,
7	Anchor, BlockId, ConfirmationBlockTime,
8	};
9	use electrum_client::{ElectrumApi, Error, HeaderNotification};
10	use std::{
11	collections::BTreeSet,
12	sync::{Arc, Mutex},
13	};
14
15	/// We include a chain suffix of a certain length for the purpose of robustness.
16	const CHAIN_SUFFIX_LENGTH: u32 = 8;
17
18	/// Wrapper around an [`electrum_client::ElectrumApi`] which includes an internal in-memory
19	/// transaction cache to avoid re-fetching already downloaded transactions.
20	#[derive(Debug)]
21	pub struct BdkElectrumClient<E> {
22	/// The internal [`electrum_client::ElectrumApi`]
23	pub inner: E,
24	/// The transaction cache
25	tx_cache: Mutex<HashMap<Txid, Arc<Transaction>>>,
26	/// The header cache
27	block_header_cache: Mutex<HashMap<u32, Header>>,
28	}
29
30	impl<E: ElectrumApi> BdkElectrumClient<E> {
31	/// Creates a new bdk client from a [`electrum_client::ElectrumApi`]
32	pub fn new(client: E) -> Self {	4✔
33	Self {	4✔
34	inner: client,	4✔
35	tx_cache: Default::default(),	4✔
36	block_header_cache: Default::default(),	4✔
37	}	4✔
38	}	4✔
39
40	/// Inserts transactions into the transaction cache so that the client will not fetch these
41	/// transactions.
42	pub fn populate_tx_cache<A>(&self, tx_graph: impl AsRef<TxGraph<A>>) {	×
43	let txs = tx_graph	×
44	.as_ref()	×
45	.full_txs()	×
46	.map(\|tx_node\| (tx_node.txid, tx_node.tx));	×
47		×
48	let mut tx_cache = self.tx_cache.lock().unwrap();	×
49	for (txid, tx) in txs {	×
50	tx_cache.insert(txid, tx);	×
51	}	×
52	}	×
53
54	/// Fetch transaction of given `txid`.
55	///
56	/// If it hits the cache it will return the cached version and avoid making the request.
57	pub fn fetch_tx(&self, txid: Txid) -> Result<Arc<Transaction>, Error> {	112✔
58	let tx_cache = self.tx_cache.lock().unwrap();	112✔
59
60	if let Some(tx) = tx_cache.get(&txid) {	112✔
61	return Ok(Arc::clone(tx));	88✔
62	}	24✔
63		24✔
64	drop(tx_cache);	24✔
65
66	let tx = Arc::new(self.inner.transaction_get(&txid)?);	24✔
67
68	self.tx_cache.lock().unwrap().insert(txid, Arc::clone(&tx));	24✔
69		24✔
70	Ok(tx)	24✔
71	}	112✔
72
73	/// Fetch block header of given `height`.
74	///
75	/// If it hits the cache it will return the cached version and avoid making the request.
76	fn fetch_header(&self, height: u32) -> Result<Header, Error> {	44✔
77	let block_header_cache = self.block_header_cache.lock().unwrap();	44✔
78
79	if let Some(header) = block_header_cache.get(&height) {	44✔
80	return Ok(*header);	31✔
81	}	13✔
82		13✔
83	drop(block_header_cache);	13✔
84		13✔
85	self.update_header(height)	13✔
86	}	44✔
87
88	/// Update a block header at given `height`. Returns the updated header.
89	fn update_header(&self, height: u32) -> Result<Header, Error> {	13✔
90	let header = self.inner.block_header(height as usize)?;	13✔
91
92	self.block_header_cache	13✔
93	.lock()	13✔
94	.unwrap()	13✔
95	.insert(height, header);	13✔
96		13✔
97	Ok(header)	13✔
98	}	13✔
99
100	/// Broadcasts a transaction to the network.
101	///
102	/// This is a re-export of [`ElectrumApi::transaction_broadcast`].
103	pub fn transaction_broadcast(&self, tx: &Transaction) -> Result<Txid, Error> {	×
104	self.inner.transaction_broadcast(tx)	×
105	}	×
106
107	/// Full scan the keychain scripts specified with the blockchain (via an Electrum client) and
108	/// returns updates for [`bdk_chain`] data structures.
109	///
110	/// - `request`: struct with data required to perform a spk-based blockchain client full scan,
111	/// see [`FullScanRequest`].
112	/// - `stop_gap`: the full scan for each keychain stops after a gap of script pubkeys with no
113	/// associated transactions.
114	/// - `batch_size`: specifies the max number of script pubkeys to request for in a single batch
115	/// request.
116	/// - `fetch_prev_txouts`: specifies whether we want previous `TxOut`s for fee calculation.
117	/// Note that this requires additional calls to the Electrum server, but
118	/// is necessary for calculating the fee on a transaction if your wallet
119	/// does not own the inputs. Methods like [`Wallet.calculate_fee`] and
120	/// [`Wallet.calculate_fee_rate`] will return a
121	/// [`CalculateFeeError::MissingTxOut`] error if those `TxOut`s are not
122	/// present in the transaction graph.
123	///
124	/// [`CalculateFeeError::MissingTxOut`]: bdk_chain::tx_graph::CalculateFeeError::MissingTxOut
125	/// [`Wallet.calculate_fee`]: https://docs.rs/bdk_wallet/latest/bdk_wallet/struct.Wallet.html#method.calculate_fee
126	/// [`Wallet.calculate_fee_rate`]: https://docs.rs/bdk_wallet/latest/bdk_wallet/struct.Wallet.html#method.calculate_fee_rate
127	pub fn full_scan<K: Ord + Clone>(	4✔
128	&self,	4✔
129	request: impl Into<FullScanRequest<K>>,	4✔
130	stop_gap: usize,	4✔
131	batch_size: usize,	4✔
132	fetch_prev_txouts: bool,	4✔
133	) -> Result<FullScanResult<K>, Error> {	4✔
134	let mut request: FullScanRequest<K> = request.into();	4✔
135
136	let tip_and_latest_blocks = match request.chain_tip() {	4✔
137	Some(chain_tip) => Some(fetch_tip_and_latest_blocks(&self.inner, chain_tip)?),	4✔
138	None => None,	×
139	};
140	let time_of_sync = request.get_time_of_sync();	4✔
141		4✔
142	let mut graph_update = TxGraph::<ConfirmationBlockTime>::default();	4✔
143	let mut last_active_indices = BTreeMap::<K, u32>::default();	4✔
144	for keychain in request.keychains() {	4✔
145	let spks = request.iter_spks(keychain.clone());	4✔
146	if let Some(last_active_index) = self.populate_with_spks(	4✔
147	&mut graph_update,	4✔
148	spks,	4✔
149	stop_gap,	4✔
150	batch_size,	4✔
151	time_of_sync,	4✔
152	)? {	4✔
153	last_active_indices.insert(keychain, last_active_index);	3✔
154	}	3✔
155	}
156
157	// Fetch previous `TxOut`s for fee calculation if flag is enabled.
158	if fetch_prev_txouts {	4✔
159	self.fetch_prev_txout(&mut graph_update)?;	×
160	}	4✔
161
162	let chain_update = match tip_and_latest_blocks {	4✔
163	Some((chain_tip, latest_blocks)) => Some(chain_update(	4✔
164	chain_tip,	4✔
165	&latest_blocks,	4✔
166	graph_update.all_anchors(),	4✔
167	)?),	4✔
168	_ => None,	×
169	};
170
171	Ok(FullScanResult {	4✔
172	graph_update,	4✔
173	chain_update,	4✔
174	last_active_indices,	4✔
175	})	4✔
176	}	4✔
177
178	/// Sync a set of scripts with the blockchain (via an Electrum client) for the data specified
179	/// and returns updates for [`bdk_chain`] data structures.
180	///
181	/// - `request`: struct with data required to perform a spk-based blockchain client sync,
182	/// see [`SyncRequest`]
183	/// - `batch_size`: specifies the max number of script pubkeys to request for in a single batch
184	/// request
185	/// - `fetch_prev_txouts`: specifies whether we want previous `TxOut`s for fee calculation.
186	/// Note that this requires additional calls to the Electrum server, but
187	/// is necessary for calculating the fee on a transaction if your wallet
188	/// does not own the inputs. Methods like [`Wallet.calculate_fee`] and
189	/// [`Wallet.calculate_fee_rate`] will return a
190	/// [`CalculateFeeError::MissingTxOut`] error if those `TxOut`s are not
191	/// present in the transaction graph.
192	///
193	/// If the scripts to sync are unknown, such as when restoring or importing a keychain that
194	/// may include scripts that have been used, use [`full_scan`] with the keychain.
195	///
196	/// [`full_scan`]: Self::full_scan
197	/// [`CalculateFeeError::MissingTxOut`]: bdk_chain::tx_graph::CalculateFeeError::MissingTxOut
198	/// [`Wallet.calculate_fee`]: https://docs.rs/bdk_wallet/latest/bdk_wallet/struct.Wallet.html#method.calculate_fee
199	/// [`Wallet.calculate_fee_rate`]: https://docs.rs/bdk_wallet/latest/bdk_wallet/struct.Wallet.html#method.calculate_fee_rate
200	pub fn sync<I: 'static>(	14✔
201	&self,	14✔
202	request: impl Into<SyncRequest<I>>,	14✔
203	batch_size: usize,	14✔
204	fetch_prev_txouts: bool,	14✔
205	) -> Result<SyncResult, Error> {	14✔
206	let mut request: SyncRequest<I> = request.into();	14✔
207
208	let tip_and_latest_blocks = match request.chain_tip() {	14✔
209	Some(chain_tip) => Some(fetch_tip_and_latest_blocks(&self.inner, chain_tip)?),	14✔
210	None => None,	×
211	};
212	let time_of_sync = request.get_time_of_sync();	14✔
213		14✔
214	let mut graph_update = TxGraph::<ConfirmationBlockTime>::default();	14✔
215	self.populate_with_spks(	14✔
216	&mut graph_update,	14✔
217	request	14✔
218	.iter_spks()	14✔
219	.enumerate()	14✔
220	.map(\|(i, spk)\| (i as u32, spk)),	15✔
221	usize::MAX,	14✔
222	batch_size,	14✔
223	time_of_sync,	14✔
224	)?;	14✔
225	self.populate_with_txids(&mut graph_update, request.iter_txids(), time_of_sync)?;	14✔
226	self.populate_with_outpoints(&mut graph_update, request.iter_outpoints(), time_of_sync)?;	14✔
227
228	// Fetch previous `TxOut`s for fee calculation if flag is enabled.
229	if fetch_prev_txouts {	14✔
230	self.fetch_prev_txout(&mut graph_update)?;	14✔
231	}	×
232
233	let chain_update = match tip_and_latest_blocks {	14✔
234	Some((chain_tip, latest_blocks)) => Some(chain_update(	14✔
235	chain_tip,	14✔
236	&latest_blocks,	14✔
237	graph_update.all_anchors(),	14✔
238	)?),	14✔
239	None => None,	×
240	};
241
242	Ok(SyncResult {	14✔
243	graph_update,	14✔
244	chain_update,	14✔
245	})	14✔
246	}	14✔
247
248	/// Populate the `graph_update` with transactions/anchors associated with the given `spks`.
249	///
250	/// Transactions that contains an output with requested spk, or spends form an output with
251	/// requested spk will be added to `graph_update`. Anchors of the aforementioned transactions are
252	/// also included.
253	fn populate_with_spks(	18✔
254	&self,	18✔
255	graph_update: &mut TxGraph<ConfirmationBlockTime>,	18✔
256	mut spks: impl Iterator<Item = (u32, ScriptBuf)>,	18✔
257	stop_gap: usize,	18✔
258	batch_size: usize,	18✔
259	time_of_sync: Option<u64>,	18✔
260	) -> Result<Option<u32>, Error> {	18✔
261	let mut unused_spk_count = 0_usize;	18✔
262	let mut last_active_index = Option::<u32>::None;	18✔
263
264	loop {	60✔
265	let spks = (0..batch_size)	60✔
266	.map_while(\|_\| spks.next())	73✔
267	.collect::<Vec<_>>();	60✔
268	if spks.is_empty() {	60✔
269	return Ok(last_active_index);	15✔
270	}	45✔
271
272	let spk_histories = self	45✔
273	.inner	45✔
274	.batch_script_get_history(spks.iter().map(\|(_, s)\| s.as_script()))?;	45✔
275
276	for ((spk_index, _spk), spk_history) in spks.into_iter().zip(spk_histories) {	45✔
277	if spk_history.is_empty() {	45✔
278	unused_spk_count = unused_spk_count.saturating_add(1);	26✔
279	if unused_spk_count >= stop_gap {	26✔
280	return Ok(last_active_index);	3✔
281	}	23✔
282	continue;	23✔
283	} else {	19✔
284	last_active_index = Some(spk_index);	19✔
285	unused_spk_count = 0;	19✔
286	}	19✔
287
288	for tx_res in spk_history {	77✔
289	let _ = graph_update.insert_tx(self.fetch_tx(tx_res.tx_hash)?);	58✔
290	self.validate_merkle_for_anchor(	58✔
291	graph_update,	58✔
292	tx_res.tx_hash,	58✔
293	tx_res.height,	58✔
294	time_of_sync,	58✔
295	)?;	58✔
296	}
297	}
298	}
299	}	18✔
300
301	/// Populate the `graph_update` with associated transactions/anchors of `outpoints`.
302	///
303	/// Transactions in which the outpoint resides, and transactions that spend from the outpoint are
304	/// included. Anchors of the aforementioned transactions are included.
305	fn populate_with_outpoints(	14✔
306	&self,	14✔
307	graph_update: &mut TxGraph<ConfirmationBlockTime>,	14✔
308	outpoints: impl IntoIterator<Item = OutPoint>,	14✔
309	time_of_sync: Option<u64>,	14✔
310	) -> Result<(), Error> {	14✔
311	for outpoint in outpoints {	14✔
312	let op_txid = outpoint.txid;	×
313	let op_tx = self.fetch_tx(op_txid)?;	×
314	let op_txout = match op_tx.output.get(outpoint.vout as usize) {	×
315	Some(txout) => txout,	×
316	None => continue,	×
317	};
318	debug_assert_eq!(op_tx.compute_txid(), op_txid);	×
319
320	// attempt to find the following transactions (alongside their chain positions), and
321	// add to our sparsechain `update`:
322	let mut has_residing = false; // tx in which the outpoint resides	×
323	let mut has_spending = false; // tx that spends the outpoint	×
324	for res in self.inner.script_get_history(&op_txout.script_pubkey)? {	×
325	if has_residing && has_spending {	×
326	break;	×
327	}	×
328		×
329	if !has_residing && res.tx_hash == op_txid {	×
330	has_residing = true;	×
331	let _ = graph_update.insert_tx(Arc::clone(&op_tx));	×
NEW 332	self.validate_merkle_for_anchor(	×
NEW 333	graph_update,	×
NEW 334	res.tx_hash,	×
NEW 335	res.height,	×
NEW 336	time_of_sync,	×
NEW 337	)?;	×
UNCOV 338	}	×
339
340	if !has_spending && res.tx_hash != op_txid {	×
341	let res_tx = self.fetch_tx(res.tx_hash)?;	×
342	// we exclude txs/anchors that do not spend our specified outpoint(s)
343	has_spending = res_tx	×
344	.input	×
345	.iter()	×
346	.any(\|txin\| txin.previous_output == outpoint);	×
347	if !has_spending {	×
348	continue;	×
349	}	×
350	let _ = graph_update.insert_tx(Arc::clone(&res_tx));	×
NEW 351	self.validate_merkle_for_anchor(	×
NEW 352	graph_update,	×
NEW 353	res.tx_hash,	×
NEW 354	res.height,	×
NEW 355	time_of_sync,	×
NEW 356	)?;	×
UNCOV 357	}	×
358	}
359	}
360	Ok(())	14✔
361	}	14✔
362
363	/// Populate the `graph_update` with transactions/anchors of the provided `txids`.
364	fn populate_with_txids(	14✔
365	&self,	14✔
366	graph_update: &mut TxGraph<ConfirmationBlockTime>,	14✔
367	txids: impl IntoIterator<Item = Txid>,	14✔
368	time_of_sync: Option<u64>,	14✔
369	) -> Result<(), Error> {	14✔
370	for txid in txids {	14✔
371	let tx = match self.fetch_tx(txid) {	×
372	Ok(tx) => tx,	×
373	Err(electrum_client::Error::Protocol(_)) => continue,	×
374	Err(other_err) => return Err(other_err),	×
375	};
376
377	let spk = tx	×
378	.output	×
379	.first()	×
380	.map(\|txo\| &txo.script_pubkey)	×
381	.expect("tx must have an output");	×
382
383	// because of restrictions of the Electrum API, we have to use the `script_get_history`
384	// call to get confirmation status of our transaction
385	if let Some(r) = self	×
386	.inner	×
387	.script_get_history(spk)?	×
388	.into_iter()	×
389	.find(\|r\| r.tx_hash == txid)	×
390	{
NEW 391	self.validate_merkle_for_anchor(graph_update, txid, r.height, time_of_sync)?;	×
392	}	×
393
394	let _ = graph_update.insert_tx(tx);	×
395	}
396	Ok(())	14✔
397	}	14✔
398
399	// Helper function which checks if a transaction is confirmed by validating the merkle proof.
400	// An anchor is inserted if the transaction is validated to be in a confirmed block.
401	fn validate_merkle_for_anchor(	58✔
402	&self,	58✔
403	graph_update: &mut TxGraph<ConfirmationBlockTime>,	58✔
404	txid: Txid,	58✔
405	confirmation_height: i32,	58✔
406	time_of_sync: Option<u64>,	58✔
407	) -> Result<(), Error> {	58✔
408	if let Ok(merkle_res) = self	58✔
409	.inner	58✔
410	.transaction_get_merkle(&txid, confirmation_height as usize)	58✔
411	{
412	let mut header = self.fetch_header(merkle_res.block_height as u32)?;	44✔
413	let mut is_confirmed_tx = electrum_client::utils::validate_merkle_proof(	44✔
414	&txid,	44✔
415	&header.merkle_root,	44✔
416	&merkle_res,	44✔
417	);	44✔
418		44✔
419	// Merkle validation will fail if the header in `block_header_cache` is outdated, so we	44✔
420	// want to check if there is a new header and validate against the new one.	44✔
421	if !is_confirmed_tx {	44✔
422	header = self.update_header(merkle_res.block_height as u32)?;	×
423	is_confirmed_tx = electrum_client::utils::validate_merkle_proof(	×
424	&txid,	×
425	&header.merkle_root,	×
426	&merkle_res,	×
427	);	×
428	}	44✔
429
430	if is_confirmed_tx {	44✔
431	let _ = graph_update.insert_anchor(	44✔
432	txid,	44✔
433	ConfirmationBlockTime {	44✔
434	confirmation_time: header.time as u64,	44✔
435	block_id: BlockId {	44✔
436	height: merkle_res.block_height as u32,	44✔
437	hash: header.block_hash(),	44✔
438	},	44✔
439	},	44✔
440	);	44✔
441	}	44✔
442	} else {
443	// If no merkle proof is returned, then the tx is unconfirmed and we set the last_seen.
444	if let Some(seen_at) = time_of_sync {	14✔
445	let _ = graph_update.insert_seen_at(txid, seen_at);	14✔
446	}	14✔
447	}
448	Ok(())	58✔
449	}	58✔
450
451	// Helper function which fetches the `TxOut`s of our relevant transactions' previous transactions,
452	// which we do not have by default. This data is needed to calculate the transaction fee.
453	fn fetch_prev_txout(	14✔
454	&self,	14✔
455	graph_update: &mut TxGraph<ConfirmationBlockTime>,	14✔
456	) -> Result<(), Error> {	14✔
457	let full_txs: Vec<Arc<Transaction>> =	14✔
458	graph_update.full_txs().map(\|tx_node\| tx_node.tx).collect();	54✔
459	for tx in full_txs {	68✔
460	for vin in &tx.input {	54✔
461	let outpoint = vin.previous_output;	54✔
462	let vout = outpoint.vout;	54✔
463	let prev_tx = self.fetch_tx(outpoint.txid)?;	54✔
464	let txout = prev_tx.output[vout as usize].clone();	54✔
465	let _ = graph_update.insert_txout(outpoint, txout);	54✔
466	}
467	}
468	Ok(())	14✔
469	}	14✔
470	}
471
472	/// Return a [`CheckPoint`] of the latest tip, that connects with `prev_tip`. The latest blocks are
473	/// fetched to construct checkpoint updates with the proper [`BlockHash`] in case of re-org.
474	fn fetch_tip_and_latest_blocks(	18✔
475	client: &impl ElectrumApi,	18✔
476	prev_tip: CheckPoint,	18✔
477	) -> Result<(CheckPoint, BTreeMap<u32, BlockHash>), Error> {	18✔
478	let HeaderNotification { height, .. } = client.block_headers_subscribe()?;	18✔
479	let new_tip_height = height as u32;	18✔
480		18✔
481	// If electrum returns a tip height that is lower than our previous tip, then checkpoints do	18✔
482	// not need updating. We just return the previous tip and use that as the point of agreement.	18✔
483	if new_tip_height < prev_tip.height() {	18✔
484	return Ok((prev_tip, BTreeMap::new()));	×
485	}	18✔
486
487	// Atomically fetch the latest `CHAIN_SUFFIX_LENGTH` count of blocks from Electrum. We use this
488	// to construct our checkpoint update.
489	let mut new_blocks = {	18✔
490	let start_height = new_tip_height.saturating_sub(CHAIN_SUFFIX_LENGTH - 1);	18✔
491	let hashes = client	18✔
492	.block_headers(start_height as _, CHAIN_SUFFIX_LENGTH as _)?	18✔
493	.headers
494	.into_iter()	18✔
495	.map(\|h\| h.block_hash());	144✔
496	(start_height..).zip(hashes).collect::<BTreeMap<u32, _>>()	18✔
497	};
498
499	// Find the "point of agreement" (if any).
500	let agreement_cp = {	18✔
501	let mut agreement_cp = Option::<CheckPoint>::None;	18✔
502	for cp in prev_tip.iter() {	55✔
503	let cp_block = cp.block_id();	55✔
504	let hash = match new_blocks.get(&cp_block.height) {	55✔
505	Some(&hash) => hash,	52✔
506	None => {
507	assert!(	3✔
508	new_tip_height >= cp_block.height,	3✔
509	"already checked that electrum's tip cannot be smaller"	×
510	);
511	let hash = client.block_header(cp_block.height as _)?.block_hash();	3✔
512	new_blocks.insert(cp_block.height, hash);	3✔
513	hash	3✔
514	}
515	};
516	if hash == cp_block.hash {	55✔
517	agreement_cp = Some(cp);	18✔
518	break;	18✔
519	}	37✔
520	}
521	agreement_cp	18✔
522	};	18✔
523		18✔
524	let agreement_height = agreement_cp.as_ref().map(CheckPoint::height);	18✔
525		18✔
526	let new_tip = new_blocks	18✔
527	.iter()	18✔
528	// Prune `new_blocks` to only include blocks that are actually new.	18✔
529	.filter(\|(height, _)\| Some(*<&u32>::clone(height)) > agreement_height)	147✔
530	.map(\|(height, hash)\| BlockId {	57✔
531	height: *height,	57✔
532	hash: *hash,	57✔
533	})	57✔
534	.fold(agreement_cp, \|prev_cp, block\| {	57✔
535	Some(match prev_cp {	57✔
536	Some(cp) => cp.push(block).expect("must extend checkpoint"),	57✔
537	None => CheckPoint::new(block),	×
538	})
539	})	57✔
540	.expect("must have at least one checkpoint");	18✔
541		18✔
542	Ok((new_tip, new_blocks))	18✔
543	}	18✔
544
545	// Add a corresponding checkpoint per anchor height if it does not yet exist. Checkpoints should not
546	// surpass `latest_blocks`.
547	fn chain_update<A: Anchor>(	18✔
548	mut tip: CheckPoint,	18✔
549	latest_blocks: &BTreeMap<u32, BlockHash>,	18✔
550	anchors: &BTreeSet<(A, Txid)>,	18✔
551	) -> Result<CheckPoint, Error> {	18✔
552	for anchor in anchors {	62✔
553	let height = anchor.0.anchor_block().height;	44✔
554		44✔
555	// Checkpoint uses the `BlockHash` from `latest_blocks` so that the hash will be consistent	44✔
556	// in case of a re-org.	44✔
557	if tip.get(height).is_none() && height <= tip.height() {	44✔
558	let hash = match latest_blocks.get(&height) {	×
559	Some(&hash) => hash,	×
560	None => anchor.0.anchor_block().hash,	×
561	};
562	tip = tip.insert(BlockId { hash, height });	×
563	}	44✔
564	}
565	Ok(tip)	18✔
566	}	18✔

bitcoindevkit / bdk / 10505233318

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