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chainntnfs/txnotifer: detect confirmations and spends of scripts at tip
In this commit, we modify the TxNotifier's ConnectTip method to also detect whether a registered script has been confirmed or spent on-chain by a transaction in the connected block. Once detected, notifications for them will be queued up for dispatch as with txids/outpoints. We've also refactored the ConnectTip method into smaller and reusable methods, which will serve useful later.
This commit is contained in:
Wilmer Paulino
parent
b579c23310
commit
ecd70deb8c
@ -7,6 +7,7 @@ import (
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"sync"
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"github.com/btcsuite/btcd/chaincfg/chainhash"
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"github.com/btcsuite/btcd/txscript"
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"github.com/btcsuite/btcd/wire"
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"github.com/btcsuite/btcutil"
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"github.com/lightningnetwork/lnd/channeldb"
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@ -1048,16 +1049,17 @@ func (n *TxNotifier) dispatchSpendDetails(ntfn *SpendNtfn, details *SpendDetail)
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// through every transaction and determine if it is relevant to any of its
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// clients. A transaction can be relevant in either of the following two ways:
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//
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// 1. One of the inputs in the transaction spends an outpoint for which we
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// currently have an active spend registration for.
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// 1. One of the inputs in the transaction spends an outpoint/output script
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// for which we currently have an active spend registration for.
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//
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// 2. The transaction is a transaction for which we currently have an active
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// confirmation registration for.
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// 2. The transaction has a txid or output script for which we currently have
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// an active confirmation registration for.
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//
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// In the event that the transaction is relevant, a confirmation/spend
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// notification will be queued for dispatch to the relevant clients.
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// Confirmation notifications will only be dispatched for transactions that have
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// met the required number of confirmations required by the client.
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// Confirmation notifications will only be dispatched for transactions/output
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// scripts that have met the required number of confirmations required by the
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// client.
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//
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// NOTE: In order to actually dispatch the relevant transaction notifications to
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// clients, NotifyHeight must be called with the same block height in order to
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@ -1075,7 +1077,7 @@ func (n *TxNotifier) ConnectTip(blockHash *chainhash.Hash, blockHeight uint32,
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defer n.Unlock()
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if blockHeight != n.currentHeight+1 {
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return fmt.Errorf("Received blocks out of order: "+
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return fmt.Errorf("received blocks out of order: "+
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"current height=%d, new height=%d",
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n.currentHeight, blockHeight)
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}
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@ -1085,119 +1087,206 @@ func (n *TxNotifier) ConnectTip(blockHash *chainhash.Hash, blockHeight uint32,
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// First, we'll iterate over all the transactions found in this block to
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// determine if it includes any relevant transactions to the TxNotifier.
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for _, tx := range txns {
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txHash := tx.Hash()
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// In order to determine if this transaction is relevant to the
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// notifier, we'll check its inputs for any outstanding spend
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// notifications.
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for i, txIn := range tx.MsgTx().TxIn {
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prevOut := txIn.PreviousOutPoint
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spendSet, ok := n.spendNotifications[prevOut]
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if !ok {
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continue
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}
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// If we have any, we'll record its spend height so that
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// notifications get dispatched to the respective
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// clients.
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spendDetails := &SpendDetail{
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SpentOutPoint: &prevOut,
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SpenderTxHash: txHash,
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SpendingTx: tx.MsgTx(),
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SpenderInputIndex: uint32(i),
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SpendingHeight: int32(blockHeight),
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}
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// TODO(wilmer): cancel pending historical rescans if any?
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spendSet.rescanStatus = rescanComplete
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spendSet.details = spendDetails
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for _, ntfn := range spendSet.ntfns {
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// In the event that this notification was aware
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// that the spending transaction of its outpoint
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// was reorged out of the chain, we'll consume
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// the reorg notification if it hasn't been
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// done yet already.
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select {
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case <-ntfn.Event.Reorg:
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default:
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}
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}
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// We'll note the outpoints spending height in order to
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// correctly handle dispatching notifications when the
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// spending transactions gets reorged out of the chain.
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opSet, exists := n.opsBySpendHeight[blockHeight]
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if !exists {
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opSet = make(map[wire.OutPoint]struct{})
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n.opsBySpendHeight[blockHeight] = opSet
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}
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opSet[prevOut] = struct{}{}
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}
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// Check if we have any pending notifications for this txid. If
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// none are found, we can proceed to the next transaction.
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confSet, ok := n.confNotifications[*txHash]
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if !ok {
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continue
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}
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Log.Debugf("Block contains txid=%v, constructing details",
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txHash)
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// If we have any, we'll record its confirmed height so that
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// notifications get dispatched when the transaction reaches the
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// clients' desired number of confirmations.
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details := &TxConfirmation{
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BlockHash: blockHash,
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BlockHeight: blockHeight,
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TxIndex: uint32(tx.Index()),
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}
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// TODO(wilmer): cancel pending historical rescans if any?
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confSet.rescanStatus = rescanComplete
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confSet.details = details
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for _, ntfn := range confSet.ntfns {
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// In the event that this notification was aware that
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// the transaction was reorged out of the chain, we'll
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// consume the reorg notification if it hasn't been done
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// yet already.
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select {
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case <-ntfn.Event.NegativeConf:
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default:
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}
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// We'll note this client's required number of
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// confirmations so that we can notify them when
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// expected.
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confHeight := blockHeight + ntfn.NumConfirmations - 1
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ntfnSet, exists := n.ntfnsByConfirmHeight[confHeight]
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if !exists {
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ntfnSet = make(map[*ConfNtfn]struct{})
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n.ntfnsByConfirmHeight[confHeight] = ntfnSet
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}
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ntfnSet[ntfn] = struct{}{}
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// We'll also note the initial confirmation height in
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// order to correctly handle dispatching notifications
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// when the transaction gets reorged out of the chain.
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txSet, exists := n.txsByInitialHeight[blockHeight]
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if !exists {
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txSet = make(map[chainhash.Hash]struct{})
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n.txsByInitialHeight[blockHeight] = txSet
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}
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txSet[*txHash] = struct{}{}
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}
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n.filterTx(
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tx, blockHash, blockHeight, n.handleConfDetailsAtTip,
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n.handleSpendDetailsAtTip,
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)
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}
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// Finally, now that we've determined which transactions were confirmed
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// and which outpoints were spent within the new block, we can update
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// their entries in their respective caches, along with all of our
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// unconfirmed transactions and unspent outpoints.
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// Finally, now that we've determined which requests were confirmed and
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// spent within the new block, we can update their entries in their
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// respective caches, along with all of our unconfirmed and unspent
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// requests.
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n.updateHints(blockHeight)
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return nil
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}
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// filterTx determines whether the transaction spends or confirms any
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// outstanding pending requests. The onConf and onSpend callbacks can be used to
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// retrieve all the requests fulfilled by this transaction as they occur.
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func (n *TxNotifier) filterTx(tx *btcutil.Tx, blockHash *chainhash.Hash,
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blockHeight uint32, onConf func(ConfRequest, *TxConfirmation),
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onSpend func(SpendRequest, *SpendDetail)) {
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// In order to determine if this transaction is relevant to the
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// notifier, we'll check its inputs for any outstanding spend
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// requests.
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txHash := tx.Hash()
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if onSpend != nil {
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// notifyDetails is a helper closure that will construct the
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// spend details of a request and hand them off to the onSpend
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// callback.
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notifyDetails := func(spendRequest SpendRequest,
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prevOut wire.OutPoint, inputIdx uint32) {
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Log.Debugf("Found spend of %v: spend_tx=%v, "+
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"block_height=%d", spendRequest, txHash,
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blockHeight)
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onSpend(spendRequest, &SpendDetail{
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SpentOutPoint: &prevOut,
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SpenderTxHash: txHash,
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SpendingTx: tx.MsgTx(),
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SpenderInputIndex: inputIdx,
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SpendingHeight: int32(blockHeight),
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})
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}
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for i, txIn := range tx.MsgTx().TxIn {
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// We'll re-derive the script of the output being spent
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// to determine if the inputs spends any registered
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// requests.
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prevOut := txIn.PreviousOutPoint
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pkScript, err := txscript.ComputePkScript(
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txIn.SignatureScript, txIn.Witness,
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)
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if err != nil {
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continue
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}
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spendRequest := SpendRequest{
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OutPoint: prevOut,
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PkScript: pkScript,
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}
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// If we have any, we'll record their spend height so
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// that notifications get dispatched to the respective
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// clients.
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if _, ok := n.spendNotifications[spendRequest]; ok {
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notifyDetails(spendRequest, prevOut, uint32(i))
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}
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spendRequest.OutPoint = ZeroOutPoint
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if _, ok := n.spendNotifications[spendRequest]; ok {
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notifyDetails(spendRequest, prevOut, uint32(i))
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}
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}
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}
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// We'll also check its outputs to determine if there are any
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// outstanding confirmation requests.
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if onConf != nil {
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// notifyDetails is a helper closure that will construct the
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// confirmation details of a request and hand them off to the
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// onConf callback.
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notifyDetails := func(confRequest ConfRequest) {
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Log.Debugf("Found initial confirmation of %v: "+
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"height=%d, hash=%v", confRequest,
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blockHeight, blockHash)
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details := &TxConfirmation{
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BlockHash: blockHash,
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BlockHeight: blockHeight,
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TxIndex: uint32(tx.Index()),
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}
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onConf(confRequest, details)
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}
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for _, txOut := range tx.MsgTx().TxOut {
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// We'll parse the script of the output to determine if
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// we have any registered requests for it or the
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// transaction itself.
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pkScript, err := txscript.ParsePkScript(txOut.PkScript)
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if err != nil {
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continue
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}
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confRequest := ConfRequest{
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TxID: *txHash,
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PkScript: pkScript,
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}
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// If we have any, we'll record their confirmed height
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// so that notifications get dispatched when they
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// reaches the clients' desired number of confirmations.
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if _, ok := n.confNotifications[confRequest]; ok {
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notifyDetails(confRequest)
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}
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confRequest.TxID = ZeroHash
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if _, ok := n.confNotifications[confRequest]; ok {
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notifyDetails(confRequest)
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}
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}
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}
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}
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// handleConfDetailsAtTip tracks the confirmation height of the txid/output
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// script in order to properly dispatch a confirmation notification after
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// meeting each request's desired number of confirmations for all current and
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// future registered clients.
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func (n *TxNotifier) handleConfDetailsAtTip(confRequest ConfRequest,
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details *TxConfirmation) {
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// TODO(wilmer): cancel pending historical rescans if any?
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confSet := n.confNotifications[confRequest]
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confSet.rescanStatus = rescanComplete
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confSet.details = details
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for _, ntfn := range confSet.ntfns {
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// In the event that this notification was aware that the
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// transaction/output script was reorged out of the chain, we'll
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// consume the reorg notification if it hasn't been done yet
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// already.
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select {
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case <-ntfn.Event.NegativeConf:
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default:
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}
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// We'll note this client's required number of confirmations so
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// that we can notify them when expected.
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confHeight := details.BlockHeight + ntfn.NumConfirmations - 1
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ntfnSet, exists := n.ntfnsByConfirmHeight[confHeight]
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if !exists {
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ntfnSet = make(map[*ConfNtfn]struct{})
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n.ntfnsByConfirmHeight[confHeight] = ntfnSet
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}
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ntfnSet[ntfn] = struct{}{}
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}
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// We'll also note the initial confirmation height in order to correctly
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// handle dispatching notifications when the transaction/output script
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// gets reorged out of the chain.
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txSet, exists := n.confsByInitialHeight[details.BlockHeight]
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if !exists {
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txSet = make(map[ConfRequest]struct{})
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n.confsByInitialHeight[details.BlockHeight] = txSet
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}
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txSet[confRequest] = struct{}{}
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}
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// handleSpendDetailsAtTip tracks the spend height of the outpoint/output script
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// in order to properly dispatch a spend notification for all current and future
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// registered clients.
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func (n *TxNotifier) handleSpendDetailsAtTip(spendRequest SpendRequest,
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details *SpendDetail) {
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// TODO(wilmer): cancel pending historical rescans if any?
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spendSet := n.spendNotifications[spendRequest]
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spendSet.rescanStatus = rescanComplete
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spendSet.details = details
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for _, ntfn := range spendSet.ntfns {
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// In the event that this notification was aware that the
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// spending transaction of its outpoint/output script was
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// reorged out of the chain, we'll consume the reorg
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// notification if it hasn't been done yet already.
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select {
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case <-ntfn.Event.Reorg:
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default:
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}
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}
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// We'll note the spending height of the request in order to correctly
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// handle dispatching notifications when the spending transactions gets
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// reorged out of the chain.
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spendHeight := uint32(details.SpendingHeight)
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opSet, exists := n.spendsByHeight[spendHeight]
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if !exists {
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opSet = make(map[SpendRequest]struct{})
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n.spendsByHeight[spendHeight] = opSet
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}
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opSet[spendRequest] = struct{}{}
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}
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// NotifyHeight dispatches confirmation and spend notifications to the clients
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// who registered for a notification which has been fulfilled at the passed
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// height.
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