forked from TrueCloudLab/neoneo-go
5bf00db2c9
The logic here is that we'll have all binary encoding/decoding done via our io package, which simplifies error handling. This functionality doesn't belong to util, so it's moved. This also expands BufBinWriter with Reset() method to fit the needs of core package.
115 lines
2.9 KiB
Go
115 lines
2.9 KiB
Go
package core
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import (
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"fmt"
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"github.com/CityOfZion/neo-go/pkg/core/storage"
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"github.com/CityOfZion/neo-go/pkg/core/transaction"
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"github.com/CityOfZion/neo-go/pkg/io"
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"github.com/CityOfZion/neo-go/pkg/util"
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)
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// UnspentCoins is mapping between transactions and their unspent
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// coin state.
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type UnspentCoins map[util.Uint256]*UnspentCoinState
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func (u UnspentCoins) getAndUpdate(s storage.Store, hash util.Uint256) (*UnspentCoinState, error) {
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if unspent, ok := u[hash]; ok {
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return unspent, nil
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}
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unspent := &UnspentCoinState{}
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key := storage.AppendPrefix(storage.STCoin, hash.BytesReverse())
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if b, err := s.Get(key); err == nil {
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if err := unspent.DecodeBinary(io.NewBinReaderFromBuf(b)); err != nil {
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return nil, fmt.Errorf("failed to decode (UnspentCoinState): %s", err)
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}
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} else {
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unspent = &UnspentCoinState{
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states: []CoinState{},
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}
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}
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u[hash] = unspent
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return unspent, nil
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}
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// UnspentCoinState hold the state of a unspent coin.
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type UnspentCoinState struct {
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states []CoinState
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}
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// NewUnspentCoinState returns a new unspent coin state with N confirmed states.
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func NewUnspentCoinState(n int) *UnspentCoinState {
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u := &UnspentCoinState{
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states: make([]CoinState, n),
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}
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for i := 0; i < n; i++ {
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u.states[i] = CoinStateConfirmed
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}
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return u
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}
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// commit writes all unspent coin states to the given Batch.
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func (u UnspentCoins) commit(b storage.Batch) error {
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buf := io.NewBufBinWriter()
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for hash, state := range u {
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if err := state.EncodeBinary(buf.BinWriter); err != nil {
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return err
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}
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key := storage.AppendPrefix(storage.STCoin, hash.BytesReverse())
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b.Put(key, buf.Bytes())
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buf.Reset()
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}
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return nil
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}
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// EncodeBinary encodes UnspentCoinState to the given BinWriter.
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func (s *UnspentCoinState) EncodeBinary(bw *io.BinWriter) error {
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bw.WriteVarUint(uint64(len(s.states)))
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for _, state := range s.states {
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bw.WriteLE(byte(state))
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}
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return bw.Err
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}
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// DecodeBinary decodes UnspentCoinState from the given BinReader.
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func (s *UnspentCoinState) DecodeBinary(br *io.BinReader) error {
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lenStates := br.ReadVarUint()
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s.states = make([]CoinState, lenStates)
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for i := 0; i < int(lenStates); i++ {
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var state uint8
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br.ReadLE(&state)
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s.states[i] = CoinState(state)
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}
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return br.Err
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}
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// IsDoubleSpend verifies that the input transactions are not double spent.
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func IsDoubleSpend(s storage.Store, tx *transaction.Transaction) bool {
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if len(tx.Inputs) == 0 {
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return false
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}
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for prevHash, inputs := range tx.GroupInputsByPrevHash() {
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unspent := &UnspentCoinState{}
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key := storage.AppendPrefix(storage.STCoin, prevHash.BytesReverse())
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if b, err := s.Get(key); err == nil {
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if err := unspent.DecodeBinary(io.NewBinReaderFromBuf(b)); err != nil {
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return false
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}
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if unspent == nil {
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return true
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}
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for _, input := range inputs {
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if int(input.PrevIndex) >= len(unspent.states) || unspent.states[input.PrevIndex] == CoinStateSpent {
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return true
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}
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}
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}
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}
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return false
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}
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