native: move OracleRequest to state package

It is used by multiple modules outside native
and produces unneeded dependencies.

pkg/core/state/oracle.go

@@ -0,0 +1,123 @@
+package state
+
+import (
+	"errors"
+	"math/big"
+	"unicode/utf8"
+
+	"github.com/nspcc-dev/neo-go/pkg/io"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
+)
+
+// OracleRequest represents oracle request.
+type OracleRequest struct {
+	OriginalTxID     util.Uint256
+	GasForResponse   uint64
+	URL              string
+	Filter           *string
+	CallbackContract util.Uint160
+	CallbackMethod   string
+	UserData         []byte
+}
+
+// Bytes return o serizalized to a byte-slice.
+func (o *OracleRequest) Bytes() []byte {
+	w := io.NewBufBinWriter()
+	o.EncodeBinary(w.BinWriter)
+	return w.Bytes()
+}
+
+// EncodeBinary implements io.Serializable.
+func (o *OracleRequest) EncodeBinary(w *io.BinWriter) {
+	stackitem.EncodeBinaryStackItem(o.toStackItem(), w)
+}
+
+// DecodeBinary implements io.Serializable.
+func (o *OracleRequest) DecodeBinary(r *io.BinReader) {
+	item := stackitem.DecodeBinaryStackItem(r)
+	if r.Err != nil || item == nil {
+		return
+	}
+	r.Err = o.fromStackItem(item)
+}
+
+func (o *OracleRequest) toStackItem() stackitem.Item {
+	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),
+	})
+}
+
+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
+}