func readCanonicalOutPoint(k []byte, op *wire.OutPoint) error {
if len(k) < 36 {
str := "short canonical outpoint"
return storeError(ErrData, str, nil)
}
copy(op.Hash[:], k)
op.Index = byteOrder.Uint32(k[32:36])
return nil
}
func (s *Store) rollback(ns walletdb.Bucket, height int32) error {
minedBalance, err := fetchMinedBalance(ns)
if err != nil {
return err
}
// Keep track of all credits that were removed from coinbase
// transactions. After detaching all blocks, if any transaction record
// exists in unmined that spends these outputs, remove them and their
// spend chains.
//
// It is necessary to keep these in memory and fix the unmined
// transactions later since blocks are removed in increasing order.
var coinBaseCredits []wire.OutPoint
it := makeBlockIterator(ns, height)
for it.next() {
b := &it.elem
log.Infof("Rolling back %d transactions from block %v height %d",
len(b.transactions), b.Hash, b.Height)
for i := range b.transactions {
txHash := &b.transactions[i]
recKey := keyTxRecord(txHash, &b.Block)
recVal := existsRawTxRecord(ns, recKey)
var rec TxRecord
err = readRawTxRecord(txHash, recVal, &rec)
if err != nil {
return err
}
err = deleteTxRecord(ns, txHash, &b.Block)
if err != nil {
return err
}
// Handle coinbase transactions specially since they are
// not moved to the unconfirmed store. A coinbase cannot
// contain any debits, but all credits should be removed
// and the mined balance decremented.
if blockchain.IsCoinBaseTx(&rec.MsgTx) {
op := wire.OutPoint{Hash: rec.Hash}
for i, output := range rec.MsgTx.TxOut {
k, v := existsCredit(ns, &rec.Hash,
uint32(i), &b.Block)
if v == nil {
continue
}
op.Index = uint32(i)
coinBaseCredits = append(coinBaseCredits, op)
unspentKey, credKey := existsUnspent(ns, &op)
if credKey != nil {
minedBalance -= coinutil.Amount(output.Value)
err = deleteRawUnspent(ns, unspentKey)
if err != nil {
return err
}
}
err = deleteRawCredit(ns, k)
if err != nil {
return err
}
}
continue
}
err = putRawUnmined(ns, txHash[:], recVal)
if err != nil {
return err
}
// For each debit recorded for this transaction, mark
// the credit it spends as unspent (as long as it still
// exists) and delete the debit. The previous output is
// recorded in the unconfirmed store for every previous
// output, not just debits.
for i, input := range rec.MsgTx.TxIn {
prevOut := &input.PreviousOutPoint
prevOutKey := canonicalOutPoint(&prevOut.Hash,
prevOut.Index)
err = putRawUnminedInput(ns, prevOutKey, rec.Hash[:])
if err != nil {
return err
}
// If this input is a debit, remove the debit
// record and mark the credit that it spent as
// unspent, incrementing the mined balance.
debKey, credKey, err := existsDebit(ns,
&rec.Hash, uint32(i), &b.Block)
if err != nil {
return err
}
if debKey == nil {
continue
}
// unspendRawCredit does not error in case the
// no credit exists for this key, but this
// behavior is correct. Since blocks are
// removed in increasing order, this credit
// may have already been removed from a
// previously removed transaction record in
// this rollback.
var amt coinutil.Amount
amt, err = unspendRawCredit(ns, credKey)
if err != nil {
return err
}
err = deleteRawDebit(ns, debKey)
if err != nil {
return err
}
// If the credit was previously removed in the
// rollback, the credit amount is zero. Only
// mark the previously spent credit as unspent
// if it still exists.
if amt == 0 {
continue
}
unspentVal, err := fetchRawCreditUnspentValue(credKey)
if err != nil {
return err
}
minedBalance += amt
err = putRawUnspent(ns, prevOutKey, unspentVal)
if err != nil {
return err
}
}
// For each detached non-coinbase credit, move the
// credit output to unmined. If the credit is marked
// unspent, it is removed from the utxo set and the
// mined balance is decremented.
//
// TODO: use a credit iterator
for i, output := range rec.MsgTx.TxOut {
k, v := existsCredit(ns, &rec.Hash, uint32(i),
&b.Block)
if v == nil {
continue
}
amt, change, err := fetchRawCreditAmountChange(v)
if err != nil {
return err
}
outPointKey := canonicalOutPoint(&rec.Hash, uint32(i))
unminedCredVal := valueUnminedCredit(amt, change)
err = putRawUnminedCredit(ns, outPointKey, unminedCredVal)
if err != nil {
return err
}
err = deleteRawCredit(ns, k)
if err != nil {
return err
}
credKey := existsRawUnspent(ns, outPointKey)
if credKey != nil {
minedBalance -= coinutil.Amount(output.Value)
err = deleteRawUnspent(ns, outPointKey)
if err != nil {
return err
}
}
}
}
err = it.delete()
if err != nil {
return err
}
}
if it.err != nil {
return it.err
}
for _, op := range coinBaseCredits {
opKey := canonicalOutPoint(&op.Hash, op.Index)
unminedKey := existsRawUnminedInput(ns, opKey)
if unminedKey != nil {
unminedVal := existsRawUnmined(ns, unminedKey)
var unminedRec TxRecord
copy(unminedRec.Hash[:], unminedKey) // Silly but need an array
err = readRawTxRecord(&unminedRec.Hash, unminedVal, &unminedRec)
if err != nil {
return err
}
log.Debugf("Transaction %v spends a removed coinbase "+
"output -- removing as well", unminedRec.Hash)
err = s.removeConflict(ns, &unminedRec)
if err != nil {
return err
}
}
}
return putMinedBalance(ns, minedBalance)
}