reference.go
/*
Copyright (c) 2018 Zettant Inc.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package bbclib
import (
"bytes"
"errors"
"fmt"
"reflect"
)
/*
BBcReference definition
The BBcReference is an input of UTXO (Unspent Transaction Output) structure and this object must accompanied by a BBcEvent object because it is an output of UTXO.
"AssetGroupID" distinguishes a type of asset, e.g., token-X, token-Y, Movie content, etc..
"TransactionID" is that of a certain transaction in the past. "EventIndexInRef" points to the BBcEvent object in the past BBcTransaction.
"SigIndices" is a mapping info between userID and the position (index) of the signature list in the BBcTransaction object.
"Transaction" is the pointer to the parent BBcTransaction object, and "RefTransaction" is the pointer to the past BBcTransaction object.
"IDLength", "Transaction", "RefTransaction" and "RefEvent" are not included in a packed data. They are for internal use only.
*/
type (
BBcReference struct {
IdLengthConf *BBcIdConfig
Version uint32
AssetGroupID []byte
TransactionID []byte
EventIndexInRef uint16
SigIndices []int
sigIndicesOptions [][]byte
Transaction *BBcTransaction
RefTransaction *BBcTransaction
RefEvent BBcEvent
}
)
// Stringer outputs the content of the object
func (p *BBcReference) Stringer() string {
ret := fmt.Sprintf(" asset_group_id: %x\n", p.AssetGroupID)
ret += fmt.Sprintf(" transaction_id: %x\n", p.TransactionID)
ret += fmt.Sprintf(" event_index_in_ref: %v\n", p.EventIndexInRef)
ret += fmt.Sprintf(" sig_indices: %v\n", p.SigIndices)
return ret
}
// Set ID length configuration
func (p *BBcReference) SetIdLengthConf(conf * BBcIdConfig) {
p.IdLengthConf = conf
}
// SetTransaction links the BBcReference object to the parent transaction object
func (p *BBcReference) SetTransaction(txobj *BBcTransaction) {
p.Transaction = txobj
}
// Add sets essential information to the BBcReference object
func (p *BBcReference) Add(assetGroupID *[]byte, refTransaction *BBcTransaction, eventIdx int) {
if assetGroupID != nil {
p.AssetGroupID = make([]byte, p.IdLengthConf.AssetGroupIdLength)
copy(p.AssetGroupID, *assetGroupID)
}
if eventIdx > -1 {
p.EventIndexInRef = uint16(eventIdx)
}
if refTransaction != nil {
p.RefTransaction = refTransaction
p.TransactionID = make([]byte, p.IdLengthConf.TransactionIdLength)
copy(p.TransactionID, refTransaction.TransactionID)
p.RefEvent = *p.RefTransaction.Events[p.EventIndexInRef]
if len(p.SigIndices) == 0 {
for i := range p.RefEvent.MandatoryApprovers {
idx := p.Transaction.GetSigIndex(p.RefEvent.MandatoryApprovers[i])
p.SigIndices = append(p.SigIndices, idx)
}
for i:=0; i<int(p.RefEvent.OptionApproverNumNumerator); i++ {
dummyId := GetRandomValue(p.Transaction.IdLengthConf.UserIdLength)
p.sigIndicesOptions = append(p.sigIndicesOptions, dummyId)
idx := p.Transaction.GetSigIndex(dummyId)
p.SigIndices = append(p.SigIndices, idx)
}
} else {
j := 0
for i := range p.RefEvent.MandatoryApprovers {
p.Transaction.SetSigIndex(p.RefEvent.MandatoryApprovers[i], p.SigIndices[j])
j += 1
}
for i:=0; i<int(p.RefEvent.OptionApproverNumNumerator); i++ {
dummyId := GetRandomValue(p.Transaction.IdLengthConf.UserIdLength)
p.sigIndicesOptions = append(p.sigIndicesOptions, dummyId)
p.Transaction.SetSigIndex(dummyId, p.SigIndices[j])
j += 1
}
}
}
}
// AddSignature sets the BBcSignature object in the object
func (p *BBcReference) AddSignature(userID *[]byte, sig *BBcSignature) error {
uid := make([]byte, p.Transaction.IdLengthConf.UserIdLength)
copy(uid, *userID)
if p.Transaction == nil {
return errors.New("transaction must be set")
}
for _, m := range p.RefEvent.MandatoryApprovers {
if reflect.DeepEqual(m, uid) {
p.Transaction.AddSignatureObj(&uid, sig)
return nil
}
}
for _, o := range p.RefEvent.OptionApprovers {
if reflect.DeepEqual(o, uid) {
u := make([]byte, p.Transaction.IdLengthConf.UserIdLength)
copy(u, p.sigIndicesOptions[0])
p.sigIndicesOptions = p.sigIndicesOptions[1:]
p.Transaction.AddSignatureObj(&u, sig)
return nil
}
}
return errors.New("the user is not specified as approver")
}
// Pack returns the binary data of the BBcReference object
func (p *BBcReference) Pack() ([]byte, error) {
buf := new(bytes.Buffer)
PutBigInt(buf, &p.AssetGroupID, p.IdLengthConf.AssetGroupIdLength)
PutBigInt(buf, &p.TransactionID, p.IdLengthConf.TransactionIdLength)
Put2byte(buf, p.EventIndexInRef)
Put2byte(buf, uint16(len(p.SigIndices)))
for i := 0; i < len(p.SigIndices); i++ {
Put2byte(buf, uint16(p.SigIndices[i]))
}
return buf.Bytes(), nil
}
// Unpack the BBcReference object to the binary data
func (p *BBcReference) Unpack(dat *[]byte) error {
if p.IdLengthConf == nil {
p.IdLengthConf = &BBcIdConfig{}
}
var err error
buf := bytes.NewBuffer(*dat)
p.AssetGroupID, p.IdLengthConf.AssetGroupIdLength, err = GetBigInt(buf)
if err != nil {
return err
}
p.TransactionID, p.IdLengthConf.TransactionIdLength, err = GetBigInt(buf)
if err != nil {
return err
}
p.EventIndexInRef, err = Get2byte(buf)
if err != nil {
return err
}
sigNum, err := Get2byte(buf)
if err != nil {
return err
}
for i := 0; i < int(sigNum); i++ {
idx, err := Get2byte(buf)
if err != nil {
return err
}
p.SigIndices = append(p.SigIndices, int(idx))
}
return nil
}