lnd.xprv/chainntnfs/neutrinonotify/neutrino_dev.go
Wilmer Paulino bfd11a251e
chainntnfs/neutrinonotify: handle spend notification registration w/ TxNotifier
In this commit, we modify the logic within RegisterSpendNtfn for the
NeutrinoNotifier 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 NeutrinoNotifier 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

100 lines
2.9 KiB
Go

// +build dev
package neutrinonotify
import (
"fmt"
"time"
"github.com/btcsuite/btcd/chaincfg/chainhash"
"github.com/btcsuite/btcd/rpcclient"
"github.com/lightninglabs/neutrino"
"github.com/lightningnetwork/lnd/chainntnfs"
)
// UnsafeStart starts the notifier with a specified best height and optional
// best hash. Its bestHeight, txNotifier and neutrino node are initialized with
// bestHeight. 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// outdated best block and miss sending ntfns.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 (n *NeutrinoNotifier) UnsafeStart(bestHeight int32,
bestHash *chainhash.Hash, syncHeight int32,
generateBlocks func() error) error {
// We'll obtain the latest block height of the p2p node. We'll
// start the auto-rescan from this point. Once a caller actually wishes
// to register a chain view, the rescan state will be rewound
// accordingly.
startingPoint, err := n.p2pNode.BestBlock()
if err != nil {
return err
}
// Next, we'll create our set of rescan options. Currently it's
// required that a user MUST set an addr/outpoint/txid when creating a
// rescan. To get around this, we'll add a "zero" outpoint, that won't
// actually be matched.
var zeroInput neutrino.InputWithScript
rescanOptions := []neutrino.RescanOption{
neutrino.StartBlock(startingPoint),
neutrino.QuitChan(n.quit),
neutrino.NotificationHandlers(
rpcclient.NotificationHandlers{
OnFilteredBlockConnected: n.onFilteredBlockConnected,
OnFilteredBlockDisconnected: n.onFilteredBlockDisconnected,
},
),
neutrino.WatchInputs(zeroInput),
}
n.txNotifier = chainntnfs.NewTxNotifier(
uint32(bestHeight), reorgSafetyLimit, n.confirmHintCache,
n.spendHintCache,
)
n.chainConn = &NeutrinoChainConn{n.p2pNode}
// Finally, we'll create our rescan struct, start it, and launch all
// the goroutines we need to operate this ChainNotifier instance.
n.chainView = n.p2pNode.NewRescan(rescanOptions...)
n.rescanErr = n.chainView.Start()
n.chainUpdates.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 := <-n.chainUpdates.ChanOut():
lastReceivedNtfn := ntfn.(*filteredBlock)
if lastReceivedNtfn.height >= uint32(syncHeight) {
break loop
}
case <-timeout:
return fmt.Errorf("unable to catch up to height %d",
syncHeight)
}
}
}
// Run notificationDispatcher after setting the notifier's best height
// to avoid a race condition.
n.bestHeight = uint32(bestHeight)
n.wg.Add(1)
go n.notificationDispatcher()
return nil
}