Esempio n. 1
0
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
}
Esempio n. 2
0
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)
}