neoneo-go/pkg/smartcontract/context/context.go
Evgenii Stratonikov 85755a4628 smartcontract: implement (*ParameterContext).GetWitness()
After all signatures were accumulated it should be possible
to extract Witness for the verifiable item.
2020-03-05 09:45:33 +03:00

207 lines
5.3 KiB
Go

package context
import (
"bytes"
"encoding/hex"
"encoding/json"
"errors"
"fmt"
"sort"
"strings"
"github.com/nspcc-dev/neo-go/pkg/core/transaction"
"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
"github.com/nspcc-dev/neo-go/pkg/io"
"github.com/nspcc-dev/neo-go/pkg/smartcontract"
"github.com/nspcc-dev/neo-go/pkg/util"
"github.com/nspcc-dev/neo-go/pkg/vm"
"github.com/nspcc-dev/neo-go/pkg/vm/emit"
"github.com/nspcc-dev/neo-go/pkg/wallet"
)
// ParameterContext represents smartcontract parameter's context.
type ParameterContext struct {
// Type is a type of a verifiable item.
Type string
// Verifiable is an object which can be (de-)serialized.
Verifiable io.Serializable
// Items is a map from script hashes to context items.
Items map[util.Uint160]*Item
}
type paramContext struct {
Type string `json:"type"`
Hex string `json:"hex"`
Items map[string]json.RawMessage `json:"items"`
}
type sigWithIndex struct {
index int
sig []byte
}
// NewParameterContext returns ParameterContext with the specified type and item to sign.
func NewParameterContext(typ string, verif io.Serializable) *ParameterContext {
return &ParameterContext{
Type: typ,
Verifiable: verif,
Items: make(map[util.Uint160]*Item),
}
}
// GetWitness returns invocation and verification scripts for the specified contract.
func (c *ParameterContext) GetWitness(ctr *wallet.Contract) (*transaction.Witness, error) {
item := c.getItemForContract(ctr)
bw := io.NewBufBinWriter()
for i := range item.Parameters {
if item.Parameters[i].Type != smartcontract.SignatureType {
return nil, errors.New("only signature parameters are supported")
} else if item.Parameters[i].Value == nil {
return nil, errors.New("nil parameter")
}
emit.Bytes(bw.BinWriter, item.Parameters[i].Value.([]byte))
}
return &transaction.Witness{
InvocationScript: bw.Bytes(),
VerificationScript: ctr.Script,
}, nil
}
// AddSignature adds a signature for the specified contract and public key.
func (c *ParameterContext) AddSignature(ctr *wallet.Contract, pub *keys.PublicKey, sig []byte) error {
item := c.getItemForContract(ctr)
if pubs, ok := vm.ParseMultiSigContract(ctr.Script); ok {
if item.GetSignature(pub) != nil {
return errors.New("signature is already added")
}
pubBytes := pub.Bytes()
var contained bool
for i := range pubs {
if bytes.Equal(pubBytes, pubs[i]) {
contained = true
break
}
}
if !contained {
return errors.New("public key is not present in script")
}
item.AddSignature(pub, sig)
if len(item.Signatures) == len(ctr.Parameters) {
indexMap := map[string]int{}
for i := range pubs {
indexMap[hex.EncodeToString(pubs[i])] = i
}
sigs := make([]sigWithIndex, 0, len(item.Signatures))
for pub, sig := range item.Signatures {
sigs = append(sigs, sigWithIndex{index: indexMap[pub], sig: sig})
}
sort.Slice(sigs, func(i, j int) bool {
return sigs[i].index < sigs[j].index
})
for i := range sigs {
item.Parameters[i] = smartcontract.Parameter{
Type: smartcontract.SignatureType,
Value: sigs[i].sig,
}
}
}
return nil
}
index := -1
for i := range ctr.Parameters {
if ctr.Parameters[i].Type == smartcontract.SignatureType {
if index >= 0 {
return errors.New("multiple signature parameters in non-multisig contract")
}
index = i
}
}
if index == -1 {
return errors.New("missing signature parameter")
}
item.Parameters[index].Value = sig
return nil
}
func (c *ParameterContext) getItemForContract(ctr *wallet.Contract) *Item {
h := ctr.ScriptHash()
if item, ok := c.Items[h]; ok {
return item
}
params := make([]smartcontract.Parameter, len(ctr.Parameters))
for i := range params {
params[i].Type = ctr.Parameters[i].Type
}
item := &Item{
Script: h,
Parameters: params,
Signatures: make(map[string][]byte),
}
c.Items[h] = item
return item
}
// MarshalJSON implements json.Marshaler interface.
func (c ParameterContext) MarshalJSON() ([]byte, error) {
bw := io.NewBufBinWriter()
c.Verifiable.EncodeBinary(bw.BinWriter)
if bw.Err != nil {
return nil, bw.Err
}
items := make(map[string]json.RawMessage, len(c.Items))
for u := range c.Items {
data, err := json.Marshal(c.Items[u])
if err != nil {
return nil, err
}
items["0x"+u.StringBE()] = data
}
pc := &paramContext{
Type: c.Type,
Hex: hex.EncodeToString(bw.Bytes()),
Items: items,
}
return json.Marshal(pc)
}
// UnmarshalJSON implements json.Unmarshaler interface.
func (c *ParameterContext) UnmarshalJSON(data []byte) error {
pc := new(paramContext)
if err := json.Unmarshal(data, pc); err != nil {
return err
}
data, err := hex.DecodeString(pc.Hex)
if err != nil {
return err
}
var verif io.Serializable
switch pc.Type {
case "Neo.Core.ContractTransaction":
verif = new(transaction.Transaction)
default:
return fmt.Errorf("unsupported type: %s", c.Type)
}
br := io.NewBinReaderFromBuf(data)
verif.DecodeBinary(br)
if br.Err != nil {
return br.Err
}
items := make(map[util.Uint160]*Item, len(pc.Items))
for h := range pc.Items {
u, err := util.Uint160DecodeStringBE(strings.TrimPrefix(h, "0x"))
if err != nil {
return err
}
item := new(Item)
if err := json.Unmarshal(pc.Items[h], item); err != nil {
return err
}
items[u] = item
}
c.Type = pc.Type
c.Verifiable = verif
c.Items = items
return nil
}