// loadUtxoView returns a utxo view loaded from a file.
func loadUtxoView(filename string) (*blockchain.UtxoViewpoint, error) {
// The utxostore file format is:
// <tx hash><serialized utxo len><serialized utxo>
//
// The serialized utxo len is a little endian uint32 and the serialized
// utxo uses the format described in chainio.go.
filename = filepath.Join("testdata", filename)
fi, err := os.Open(filename)
if err != nil {
return nil, err
}
// Choose read based on whether the file is compressed or not.
var r io.Reader
if strings.HasSuffix(filename, ".bz2") {
r = bzip2.NewReader(fi)
} else {
r = fi
}
defer fi.Close()
view := blockchain.NewUtxoViewpoint()
for {
// Hash of the utxo entry.
var hash chainhash.Hash
_, err := io.ReadAtLeast(r, hash[:], len(hash[:]))
if err != nil {
// Expected EOF at the right offset.
if err == io.EOF {
break
}
return nil, err
}
// Num of serialize utxo entry bytes.
var numBytes uint32
err = binary.Read(r, binary.LittleEndian, &numBytes)
if err != nil {
return nil, err
}
// Serialized utxo entry.
serialized := make([]byte, numBytes)
_, err = io.ReadAtLeast(r, serialized, int(numBytes))
if err != nil {
return nil, err
}
// Deserialize it and add it to the view.
utxoEntry, err := blockchain.TstDeserializeUtxoEntry(serialized)
if err != nil {
return nil, err
}
view.Entries()[hash] = utxoEntry
}
return view, nil
}
// makeUtxoView creates a mock unspent transaction output view by using the
// transaction index in order to look up all inputs referenced by the
// transactions in the block. This is sometimes needed when catching indexes up
// because many of the txouts could actually already be spent however the
// associated scripts are still required to index them.
func makeUtxoView(dbTx database.Tx, block, parent *dcrutil.Block) (*blockchain.UtxoViewpoint, error) {
view := blockchain.NewUtxoViewpoint()
regularTxTreeValid := dcrutil.IsFlagSet16(block.MsgBlock().Header.VoteBits,
dcrutil.BlockValid)
if regularTxTreeValid {
for txIdx, tx := range parent.Transactions() {
// Coinbases do not reference any inputs. Since the block is
// required to have already gone through full validation, it has
// already been proven on the first transaction in the block is
// a coinbase.
if txIdx == 0 {
continue
}
// Use the transaction index to load all of the referenced
// inputs and add their outputs to the view.
for _, txIn := range tx.MsgTx().TxIn {
// Skip already fetched outputs.
originOut := &txIn.PreviousOutPoint
if view.LookupEntry(&originOut.Hash) != nil {
continue
}
originTx, err := dbFetchTx(dbTx, originOut.Hash)
if err != nil {
return nil, err
}
view.AddTxOuts(dcrutil.NewTx(originTx),
int64(wire.NullBlockHeight), wire.NullBlockIndex)
}
}
}
for _, tx := range block.STransactions() {
msgTx := tx.MsgTx()
isSSGen, _ := stake.IsSSGen(msgTx)
// Use the transaction index to load all of the referenced
// inputs and add their outputs to the view.
for i, txIn := range msgTx.TxIn {
// Skip stakebases.
if isSSGen && i == 0 {
continue
}
originOut := &txIn.PreviousOutPoint
if view.LookupEntry(&originOut.Hash) != nil {
continue
}
originTx, err := dbFetchTx(dbTx, originOut.Hash)
if err != nil {
return nil, err
}
view.AddTxOuts(dcrutil.NewTx(originTx), int64(wire.NullBlockHeight),
wire.NullBlockIndex)
}
}
return view, nil
}