lnd.xprv/chainntnfs/btcdnotify/btcd_dev.go
Wilmer Paulino 88edd320d5
chainntnfs/btcdnotify: handle spend notification registration w/ TxNotifier
In this commit, we modify the logic within RegisterSpendNtfn for the
BtcdNotifier to account for the recent changes made to the TxNotifier.
Since it is now able to handle spend notification registration and
dispatch, we can bypass all the current logic within the
BtcdNotifier and interact directly with the TxNotifier instead.

The most notable change is that now we'll only attempt a historical
rescan if the TxNotifier tells us so.
2018-10-30 17:59:31 -07:00

81 lines
2.1 KiB
Go

// +build dev
package btcdnotify
import (
"fmt"
"time"
"github.com/btcsuite/btcd/chaincfg/chainhash"
"github.com/lightningnetwork/lnd/chainntnfs"
)
// UnsafeStart starts the notifier with a specified best height and optional
// best hash. Its bestBlock and txNotifier are initialized with bestHeight and
// optionally bestHash. The parameter generateBlocks is necessary for the
// bitcoind notifier to ensure we drain all notifications up to syncHeight,
// since if they are generated ahead of UnsafeStart the chainConn may start up
// with an outdated best block and miss sending ntfns. Used for testing.
func (b *BtcdNotifier) UnsafeStart(bestHeight int32, bestHash *chainhash.Hash,
syncHeight int32, generateBlocks func() error) error {
// Connect to btcd, and register for notifications on connected, and
// disconnected blocks.
if err := b.chainConn.Connect(20); err != nil {
return err
}
if err := b.chainConn.NotifyBlocks(); err != nil {
return err
}
b.txNotifier = chainntnfs.NewTxNotifier(
uint32(bestHeight), reorgSafetyLimit, b.confirmHintCache,
b.spendHintCache,
)
b.chainUpdates.Start()
b.txUpdates.Start()
if generateBlocks != nil {
// Ensure no block notifications are pending when we start the
// notification dispatcher goroutine.
// First generate the blocks, then drain the notifications
// for the generated blocks.
if err := generateBlocks(); err != nil {
return err
}
timeout := time.After(60 * time.Second)
loop:
for {
select {
case ntfn := <-b.chainUpdates.ChanOut():
lastReceivedNtfn := ntfn.(*chainUpdate)
if lastReceivedNtfn.blockHeight >= syncHeight {
break loop
}
case <-timeout:
return fmt.Errorf("unable to catch up to height %d",
syncHeight)
}
}
}
// Run notificationDispatcher after setting the notifier's best block
// to avoid a race condition.
b.bestBlock = chainntnfs.BlockEpoch{Height: bestHeight, Hash: bestHash}
if bestHash == nil {
hash, err := b.chainConn.GetBlockHash(int64(bestHeight))
if err != nil {
return err
}
b.bestBlock.Hash = hash
}
b.wg.Add(1)
go b.notificationDispatcher()
return nil
}