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" "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 crypto.VerifiableDecodable // 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 crypto.VerifiableDecodable) *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) { verif := c.Verifiable.GetSignedPart() 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 := ¶mContext{ Type: c.Type, Hex: hex.EncodeToString(verif), 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 crypto.VerifiableDecodable switch pc.Type { case "Neo.Core.ContractTransaction": verif = new(transaction.Transaction) default: return fmt.Errorf("unsupported type: %s", c.Type) } err = verif.DecodeSignedPart(data) if err != nil { return 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 }