package neutrinonotify import ( "fmt" "time" "github.com/btcsuite/btcd/chaincfg/chainhash" "github.com/btcsuite/btcd/rpcclient" "github.com/btcsuite/btcwallet/waddrmgr" "github.com/lightninglabs/neutrino" "github.com/lightningnetwork/lnd/chainntnfs" ) // UnsafeStart starts the notifier with a specified best height and optional // best hash. Its bestHeight, txConfNotifier 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up to syncHeight, // since if they are generated ahead of UnsafeStart the chainConn may start // up with an outdated best block and miss sending ntfns.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. header, height, err := n.p2pNode.BlockHeaders.ChainTip() if err != nil { return err } startingPoint := &waddrmgr.BlockStamp{ Height: int32(height), Hash: header.BlockHash(), } // 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.txConfNotifier = chainntnfs.NewTxConfNotifier( uint32(bestHeight), reorgSafetyLimit) 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 }