neoneo-go/pkg/core/state/oracle.go

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package state
import (
"errors"
"math/big"
"unicode/utf8"
"github.com/nspcc-dev/neo-go/pkg/util"
"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
)
// OracleRequest represents an oracle request.
type OracleRequest struct {
OriginalTxID util.Uint256
GasForResponse uint64
URL string
Filter *string
CallbackContract util.Uint160
CallbackMethod string
UserData []byte
}
// ToStackItem implements stackitem.Convertible interface. It never returns an
// error.
func (o *OracleRequest) ToStackItem() (stackitem.Item, error) {
filter := stackitem.Item(stackitem.Null{})
if o.Filter != nil {
filter = stackitem.Make(*o.Filter)
}
return stackitem.NewArray([]stackitem.Item{
stackitem.NewByteArray(o.OriginalTxID.BytesBE()),
stackitem.NewBigInteger(new(big.Int).SetUint64(o.GasForResponse)),
stackitem.Make(o.URL),
filter,
stackitem.NewByteArray(o.CallbackContract.BytesBE()),
stackitem.Make(o.CallbackMethod),
stackitem.NewByteArray(o.UserData),
}), nil
}
// FromStackItem implements stackitem.Convertible interface.
func (o *OracleRequest) FromStackItem(it stackitem.Item) error {
arr, ok := it.Value().([]stackitem.Item)
if !ok || len(arr) < 7 {
return errors.New("not an array of needed length")
}
bs, err := arr[0].TryBytes()
if err != nil {
return err
}
o.OriginalTxID, err = util.Uint256DecodeBytesBE(bs)
if err != nil {
return err
}
gas, err := arr[1].TryInteger()
if err != nil {
return err
}
o.GasForResponse = gas.Uint64()
s, isNull, ok := itemToString(arr[2])
if !ok || isNull {
return errors.New("invalid URL")
}
o.URL = s
s, isNull, ok = itemToString(arr[3])
if !ok {
return errors.New("invalid filter")
} else if !isNull {
filter := s
o.Filter = &filter
}
bs, err = arr[4].TryBytes()
if err != nil {
return err
}
o.CallbackContract, err = util.Uint160DecodeBytesBE(bs)
if err != nil {
return err
}
o.CallbackMethod, isNull, ok = itemToString(arr[5])
if !ok || isNull {
return errors.New("invalid callback method")
}
o.UserData, err = arr[6].TryBytes()
return err
}
func itemToString(it stackitem.Item) (string, bool, bool) {
_, ok := it.(stackitem.Null)
if ok {
return "", true, true
}
bs, err := it.TryBytes()
if err != nil || !utf8.Valid(bs) {
return "", false, false
}
return string(bs), false, true
}