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lightningnetwork / lnd / 14060408908

25 Mar 2025 01:08PM UTC coverage: 68.744% (-0.3%) from 69.02%
14060408908

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Merge pull request #9621 from jjjike2021/exp/maps

multi: remove x/exp/maps dependency

4 of 4 new or added lines in 4 files covered. (100.0%)

561 existing lines in 39 files now uncovered.

132512 of 192761 relevant lines covered (68.74%)

42821.37 hits per line

Source File
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89.19
/chainntnfs/mempool.go
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package chainntnfs
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3
import (
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        "sync"
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        "sync/atomic"
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        "github.com/btcsuite/btcd/btcutil"
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        "github.com/btcsuite/btcd/wire"
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        "github.com/lightningnetwork/lnd/lnutils"
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)
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// inputsWithTx is a map of outpoints to the tx that spends them.
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type inputsWithTx map[wire.OutPoint]*SpendDetail
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// MempoolNotifier defines an internal mempool notifier that's used to notify
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// the spending of given inputs. This is mounted to either `BitcoindNotifier`
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// or `BtcdNotifier` depending on the chain backend.
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type MempoolNotifier struct {
19
        wg sync.WaitGroup
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        // subscribedInputs stores the inputs that we want to watch their
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        // spending event for.
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        subscribedInputs *lnutils.SyncMap[wire.OutPoint,
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                *lnutils.SyncMap[uint64, *MempoolSpendEvent]]
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        // sCounter is used to generate unique subscription IDs.
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        sCounter atomic.Uint64
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        // quit is closed when the notifier is torn down.
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        quit chan struct{}
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}
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// MempoolSpendEvent is returned to the subscriber to watch for the spending
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// event for the requested input.
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type MempoolSpendEvent struct {
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        // Spend is a receive only channel which will be sent upon once the
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        // target outpoint has been spent.
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        //
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        // NOTE: This channel must be buffered.
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        Spend <-chan *SpendDetail
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        // id is the unique identifier of this subscription.
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        id uint64
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        // outpoint is the subscribed outpoint.
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        outpoint wire.OutPoint
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        // event is the channel that will be sent upon once the target outpoint
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        // is spent.
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        event chan *SpendDetail
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        // cancel cancels the subscription.
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        cancel chan struct{}
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}
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// newMempoolSpendEvent returns a new instance of MempoolSpendEvent.
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func newMempoolSpendEvent(id uint64, op wire.OutPoint) *MempoolSpendEvent {
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        sub := &MempoolSpendEvent{
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                id:       id,
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                outpoint: op,
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                event:    make(chan *SpendDetail, 1),
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                cancel:   make(chan struct{}),
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        }
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        // Mount the receive only channel to the event channel.
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        sub.Spend = (<-chan *SpendDetail)(sub.event)
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        return sub
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}
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// NewMempoolNotifier takes a chain connection and returns a new mempool
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// notifier.
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func NewMempoolNotifier() *MempoolNotifier {
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        return &MempoolNotifier{
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                subscribedInputs: &lnutils.SyncMap[
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                        wire.OutPoint, *lnutils.SyncMap[
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                                uint64, *MempoolSpendEvent,
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                        ]]{},
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                quit: make(chan struct{}),
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        }
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}
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// SubscribeInput takes an outpoint of the input and returns a channel that the
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// subscriber can listen to for the spending event.
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func (m *MempoolNotifier) SubscribeInput(
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        outpoint wire.OutPoint) *MempoolSpendEvent {
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        // Get the current subscribers for this input or create a new one.
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        clients := &lnutils.SyncMap[uint64, *MempoolSpendEvent]{}
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        clients, _ = m.subscribedInputs.LoadOrStore(outpoint, clients)
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        // Increment the subscription counter and return the new value.
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        subscriptionID := m.sCounter.Add(1)
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        // Create a new subscription.
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        sub := newMempoolSpendEvent(subscriptionID, outpoint)
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        // Add the subscriber with a unique id.
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        clients.Store(subscriptionID, sub)
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        // Update the subscribed inputs.
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        m.subscribedInputs.Store(outpoint, clients)
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        Log.Debugf("Subscribed(id=%v) mempool event for input=%s",
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                subscriptionID, outpoint)
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        return sub
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}
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// UnsubscribeInput removes all the subscriptions for the given outpoint.
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func (m *MempoolNotifier) UnsubscribeInput(outpoint wire.OutPoint) {
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        Log.Debugf("Unsubscribing MempoolSpendEvent for input %s", outpoint)
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        m.subscribedInputs.Delete(outpoint)
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}
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// UnsubscribeEvent removes a given subscriber for the given MempoolSpendEvent.
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func (m *MempoolNotifier) UnsubscribeEvent(sub *MempoolSpendEvent) {
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        Log.Debugf("Unsubscribing(id=%v) MempoolSpendEvent for input=%s",
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                sub.id, sub.outpoint)
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        // Load all the subscribers for this input.
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        clients, loaded := m.subscribedInputs.Load(sub.outpoint)
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        if !loaded {
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                Log.Debugf("No subscribers for input %s", sub.outpoint)
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                return
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        }
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        // Load the subscriber.
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        subscriber, loaded := clients.Load(sub.id)
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        if !loaded {
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                Log.Debugf("No subscribers for input %s with id %v",
×
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                        sub.outpoint, sub.id)
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                return
×
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        }
×
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        // Close the cancel channel in case it's been used in a goroutine.
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        close(subscriber.cancel)
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        // Remove the subscriber.
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        clients.Delete(sub.id)
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}
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// UnsubsribeConfirmedSpentTx takes a transaction and removes the subscriptions
144
// identified using its inputs.
145
func (m *MempoolNotifier) UnsubsribeConfirmedSpentTx(tx *btcutil.Tx) {
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        Log.Tracef("Unsubscribe confirmed tx %s", tx.Hash())
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        // Get the spent inputs of interest.
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        spentInputs, err := m.findRelevantInputs(tx)
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        if err != nil {
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                Log.Errorf("Unable to find relevant inputs for tx %s: %v",
×
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                        tx.Hash(), err)
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×
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                return
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        }
×
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157
        // Unsubscribe the subscribers.
158
        for outpoint := range spentInputs {
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                m.UnsubscribeInput(outpoint)
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        }
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162
        Log.Tracef("Finished unsubscribing confirmed tx %s, found %d inputs",
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                tx.Hash(), len(spentInputs))
66✔
164
}
165

166
// ProcessRelevantSpendTx takes a transaction and checks whether it spends any
167
// of the subscribed inputs. If so, spend notifications are sent to the
168
// relevant subscribers.
169
func (m *MempoolNotifier) ProcessRelevantSpendTx(tx *btcutil.Tx) error {
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        Log.Tracef("Processing mempool tx %s", tx.Hash())
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        defer Log.Tracef("Finished processing mempool tx %s", tx.Hash())
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        // Get the spent inputs of interest.
78✔
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        spentInputs, err := m.findRelevantInputs(tx)
78✔
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        if err != nil {
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                return err
×
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        }
×
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        // Notify the subscribers.
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        m.notifySpent(spentInputs)
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        return nil
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}
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// TearDown stops the notifier and cleans up resources.
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func (m *MempoolNotifier) TearDown() {
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        Log.Infof("Stopping mempool notifier")
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        defer Log.Debug("mempool notifier stopped")
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        close(m.quit)
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        m.wg.Wait()
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}
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// findRelevantInputs takes a transaction to find the subscribed inputs and
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// returns them.
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func (m *MempoolNotifier) findRelevantInputs(tx *btcutil.Tx) (inputsWithTx,
197
        error) {
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        txid := tx.Hash()
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        watchedInputs := make(inputsWithTx)
146✔
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146✔
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        // NOTE: we may have found multiple targeted inputs in the same tx.
146✔
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        for i, input := range tx.MsgTx().TxIn {
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                op := &input.PreviousOutPoint
150✔
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150✔
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                // Check whether this input is subscribed.
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                _, loaded := m.subscribedInputs.Load(*op)
150✔
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                if !loaded {
294✔
209
                        continue
144✔
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                }
211

212
                // If found, save it to watchedInputs to notify the
213
                // subscriber later.
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                Log.Debugf("Found input %s, spent in %s", op, txid)
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                // Construct the spend details.
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                details := &SpendDetail{
8✔
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                        SpentOutPoint:     op,
8✔
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                        SpenderTxHash:     txid,
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                        SpendingTx:        tx.MsgTx().Copy(),
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                        SpenderInputIndex: uint32(i),
8✔
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                        SpendingHeight:    0,
8✔
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                }
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                watchedInputs[*op] = details
8✔
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                // Sanity check the witness stack. If it's not empty, continue
8✔
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                // to next iteration.
8✔
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                if details.HasSpenderWitness() {
14✔
229
                        continue
6✔
230
                }
231

232
                // Return an error if the witness data is not present in the
233
                // spending transaction.
234
                Log.Criticalf("Found spending tx for outpoint=%v in mempool, "+
2✔
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                        "but the transaction %v does not have witness",
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                        op, details.SpendingTx.TxHash())
2✔
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2✔
238
                return nil, ErrEmptyWitnessStack
2✔
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        }
240

241
        return watchedInputs, nil
144✔
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}
243

244
// notifySpent iterates all the spentInputs and notifies the subscribers about
245
// the spent details.
246
func (m *MempoolNotifier) notifySpent(spentInputs inputsWithTx) {
86✔
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        // notifySingle sends a notification to a single subscriber about the
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        // spending event.
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        //
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        // NOTE: must be used inside a goroutine.
86✔
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        notifySingle := func(id uint64, sub *MempoolSpendEvent,
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                op wire.OutPoint, detail *SpendDetail) {
100✔
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14✔
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                defer m.wg.Done()
14✔
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14✔
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                // Send the spend details to the subscriber.
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                select {
14✔
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                case sub.event <- detail:
14✔
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                        Log.Debugf("Notified(id=%v) mempool spent for input %s",
14✔
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                                sub.id, op)
14✔
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262
                case <-sub.cancel:
×
263
                        Log.Debugf("Subscription(id=%v) canceled, skipped "+
×
264
                                "notifying spent for input %s", sub.id, op)
×
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266
                case <-m.quit:
×
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                        Log.Debugf("Mempool notifier quit, skipped notifying "+
×
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                                "mempool spent for input %s", op)
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                }
270
        }
271

272
        // notifyAll is a helper closure that constructs a spend detail and
273
        // sends it to all the subscribers of that particular input.
274
        //
275
        // NOTE: must be used inside a goroutine.
276
        notifyAll := func(detail *SpendDetail, op wire.OutPoint) {
98✔
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                defer m.wg.Done()
12✔
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12✔
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                txid := detail.SpendingTx.TxHash()
12✔
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                Log.Debugf("Notifying all clients for the spend of %s in tx %s",
12✔
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                        op, txid)
12✔
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12✔
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                // Load the subscriber.
12✔
284
                subs, loaded := m.subscribedInputs.Load(op)
12✔
285
                if !loaded {
12✔
UNCOV
286
                        Log.Errorf("Sub not found for %s", op)
×
UNCOV
287
                        return
×
UNCOV
288
                }
×
289

290
                // Iterate all the subscribers for this input and notify them.
291
                subs.ForEach(func(id uint64, sub *MempoolSpendEvent) error {
26✔
292
                        m.wg.Add(1)
14✔
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                        go notifySingle(id, sub, op, detail)
14✔
294

14✔
295
                        return nil
14✔
296
                })
14✔
297
        }
298

299
        // Iterate the spent inputs to notify the subscribers concurrently.
300
        for op, tx := range spentInputs {
98✔
301
                op, tx := op, tx
12✔
302

12✔
303
                m.wg.Add(1)
12✔
304
                go notifyAll(tx, op)
12✔
305
        }
12✔
306
}
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