475 lines
14 KiB
Go
475 lines
14 KiB
Go
package native
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import (
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"encoding/binary"
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"errors"
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"fmt"
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"math"
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"math/big"
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"strings"
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"sync/atomic"
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"github.com/nspcc-dev/neo-go/pkg/core/blockchainer/services"
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"github.com/nspcc-dev/neo-go/pkg/core/dao"
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"github.com/nspcc-dev/neo-go/pkg/core/interop"
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"github.com/nspcc-dev/neo-go/pkg/core/interop/contract"
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"github.com/nspcc-dev/neo-go/pkg/core/interop/interopnames"
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"github.com/nspcc-dev/neo-go/pkg/core/native/nativenames"
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"github.com/nspcc-dev/neo-go/pkg/core/state"
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"github.com/nspcc-dev/neo-go/pkg/core/storage"
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"github.com/nspcc-dev/neo-go/pkg/core/transaction"
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"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
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"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
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"github.com/nspcc-dev/neo-go/pkg/encoding/bigint"
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"github.com/nspcc-dev/neo-go/pkg/io"
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"github.com/nspcc-dev/neo-go/pkg/smartcontract"
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"github.com/nspcc-dev/neo-go/pkg/smartcontract/callflag"
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"github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest"
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"github.com/nspcc-dev/neo-go/pkg/util"
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"github.com/nspcc-dev/neo-go/pkg/vm/emit"
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"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
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"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
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)
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// Oracle represents Oracle native contract.
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type Oracle struct {
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interop.ContractMD
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GAS *GAS
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NEO *NEO
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Desig *Designate
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oracleScript []byte
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// Module is an oracle module capable of talking with the external world.
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Module atomic.Value
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// newRequests contains new requests created during current block.
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newRequests map[uint64]*state.OracleRequest
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}
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const (
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oracleContractID = -7
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maxURLLength = 256
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maxFilterLength = 128
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maxCallbackLength = 32
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maxUserDataLength = 512
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// maxRequestsCount is the maximum number of requests per URL
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maxRequestsCount = 256
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oracleRequestPrice = 5000_0000
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)
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var (
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prefixIDList = []byte{6}
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prefixRequest = []byte{7}
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prefixRequestID = []byte{9}
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)
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// Various validation errors.
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var (
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ErrBigArgument = errors.New("some of the arguments are invalid")
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ErrInvalidWitness = errors.New("witness check failed")
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ErrNotEnoughGas = errors.New("gas limit exceeded")
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ErrRequestNotFound = errors.New("oracle request not found")
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ErrResponseNotFound = errors.New("oracle response not found")
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)
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func newOracle() *Oracle {
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o := &Oracle{ContractMD: *interop.NewContractMD(nativenames.Oracle, oracleContractID)}
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w := io.NewBufBinWriter()
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emit.Opcodes(w.BinWriter, opcode.NEWARRAY0)
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emit.Int(w.BinWriter, int64(callflag.All))
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emit.String(w.BinWriter, "finish")
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emit.Bytes(w.BinWriter, o.Hash.BytesBE())
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emit.Syscall(w.BinWriter, interopnames.SystemContractCall)
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o.oracleScript = w.Bytes()
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desc := newDescriptor("request", smartcontract.VoidType,
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manifest.NewParameter("url", smartcontract.StringType),
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manifest.NewParameter("filter", smartcontract.StringType),
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manifest.NewParameter("callback", smartcontract.StringType),
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manifest.NewParameter("userData", smartcontract.AnyType),
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manifest.NewParameter("gasForResponse", smartcontract.IntegerType))
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md := newMethodAndPrice(o.request, oracleRequestPrice, callflag.WriteStates|callflag.AllowNotify)
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o.AddMethod(md, desc)
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desc = newDescriptor("finish", smartcontract.VoidType)
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md = newMethodAndPrice(o.finish, 0, callflag.WriteStates|callflag.AllowCall|callflag.AllowNotify)
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o.AddMethod(md, desc)
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desc = newDescriptor("verify", smartcontract.BoolType)
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md = newMethodAndPrice(o.verify, 100_0000, callflag.NoneFlag)
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o.AddMethod(md, desc)
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o.AddEvent("OracleRequest", manifest.NewParameter("Id", smartcontract.IntegerType),
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manifest.NewParameter("RequestContract", smartcontract.Hash160Type),
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manifest.NewParameter("Url", smartcontract.StringType),
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manifest.NewParameter("Filter", smartcontract.StringType))
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o.AddEvent("OracleResponse", manifest.NewParameter("Id", smartcontract.IntegerType),
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manifest.NewParameter("OriginalTx", smartcontract.Hash256Type))
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return o
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}
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// GetOracleResponseScript returns script for transaction with oracle response.
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func (o *Oracle) GetOracleResponseScript() []byte {
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b := make([]byte, len(o.oracleScript))
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copy(b, o.oracleScript)
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return b
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}
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// OnPersist implements Contract interface.
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func (o *Oracle) OnPersist(ic *interop.Context) error {
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var err error
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if o.newRequests == nil {
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o.newRequests, err = o.getRequests(ic.DAO)
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}
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return err
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}
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// PostPersist represents `postPersist` method.
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func (o *Oracle) PostPersist(ic *interop.Context) error {
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var nodes keys.PublicKeys
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var reward []big.Int
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single := new(big.Int).SetUint64(oracleRequestPrice)
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var removedIDs []uint64
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orc, _ := o.Module.Load().(services.Oracle)
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for _, tx := range ic.Block.Transactions {
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resp := getResponse(tx)
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if resp == nil {
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continue
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}
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reqKey := makeRequestKey(resp.ID)
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req := new(state.OracleRequest)
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if err := o.getSerializableFromDAO(ic.DAO, reqKey, req); err != nil {
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continue
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}
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if err := ic.DAO.DeleteStorageItem(o.ID, reqKey); err != nil {
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return err
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}
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if orc != nil {
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removedIDs = append(removedIDs, resp.ID)
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}
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idKey := makeIDListKey(req.URL)
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idList := new(IDList)
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if err := o.getSerializableFromDAO(ic.DAO, idKey, idList); err != nil {
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return err
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}
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if !idList.Remove(resp.ID) {
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return errors.New("response ID wasn't found")
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}
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var err error
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if len(*idList) == 0 {
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err = ic.DAO.DeleteStorageItem(o.ID, idKey)
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} else {
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si := &state.StorageItem{Value: idList.Bytes()}
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err = ic.DAO.PutStorageItem(o.ID, idKey, si)
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}
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if err != nil {
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return err
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}
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if nodes == nil {
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nodes, err = o.GetOracleNodes(ic.DAO)
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if err != nil {
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return err
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}
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reward = make([]big.Int, len(nodes))
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}
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if len(reward) > 0 {
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index := resp.ID % uint64(len(nodes))
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reward[index].Add(&reward[index], single)
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}
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}
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for i := range reward {
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o.GAS.mint(ic, nodes[i].GetScriptHash(), &reward[i], false)
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}
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if len(removedIDs) != 0 && orc != nil {
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orc.RemoveRequests(removedIDs)
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}
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return o.updateCache(ic.DAO)
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}
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// Metadata returns contract metadata.
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func (o *Oracle) Metadata() *interop.ContractMD {
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return &o.ContractMD
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}
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// Initialize initializes Oracle contract.
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func (o *Oracle) Initialize(ic *interop.Context) error {
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return setIntWithKey(o.ID, ic.DAO, prefixRequestID, 0)
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}
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func getResponse(tx *transaction.Transaction) *transaction.OracleResponse {
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for i := range tx.Attributes {
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if tx.Attributes[i].Type == transaction.OracleResponseT {
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return tx.Attributes[i].Value.(*transaction.OracleResponse)
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}
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}
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return nil
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}
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func (o *Oracle) finish(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
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err := o.FinishInternal(ic)
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if err != nil {
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panic(err)
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}
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return stackitem.Null{}
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}
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// FinishInternal processes oracle response.
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func (o *Oracle) FinishInternal(ic *interop.Context) error {
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resp := getResponse(ic.Tx)
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if resp == nil {
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return ErrResponseNotFound
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}
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req, err := o.GetRequestInternal(ic.DAO, resp.ID)
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if err != nil {
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return ErrRequestNotFound
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}
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ic.Notifications = append(ic.Notifications, state.NotificationEvent{
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ScriptHash: o.Hash,
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Name: "OracleResponse",
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Item: stackitem.NewArray([]stackitem.Item{
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stackitem.Make(resp.ID),
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stackitem.Make(req.OriginalTxID.BytesBE()),
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}),
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})
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r := io.NewBinReaderFromBuf(req.UserData)
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userData := stackitem.DecodeBinaryStackItem(r)
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args := []stackitem.Item{
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stackitem.Make(req.URL),
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stackitem.Make(userData),
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stackitem.Make(resp.Code),
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stackitem.Make(resp.Result),
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}
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cs, err := ic.GetContract(req.CallbackContract)
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if err != nil {
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return err
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}
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return contract.CallFromNative(ic, o.Hash, cs, req.CallbackMethod, args, false)
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}
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func (o *Oracle) request(ic *interop.Context, args []stackitem.Item) stackitem.Item {
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url, err := stackitem.ToString(args[0])
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if err != nil {
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panic(err)
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}
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var filter *string
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_, ok := args[1].(stackitem.Null)
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if !ok {
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// Check UTF-8 validity.
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str, err := stackitem.ToString(args[1])
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if err != nil {
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panic(err)
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}
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filter = &str
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}
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cb, err := stackitem.ToString(args[2])
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if err != nil {
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panic(err)
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}
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userData := args[3]
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gas, err := args[4].TryInteger()
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if err != nil {
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panic(err)
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}
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if err := o.RequestInternal(ic, url, filter, cb, userData, gas); err != nil {
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panic(err)
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}
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return stackitem.Null{}
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}
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// RequestInternal processes oracle request.
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func (o *Oracle) RequestInternal(ic *interop.Context, url string, filter *string, cb string, userData stackitem.Item, gas *big.Int) error {
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if len(url) > maxURLLength || (filter != nil && len(*filter) > maxFilterLength) || len(cb) > maxCallbackLength || gas.Uint64() < 1000_0000 {
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return ErrBigArgument
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}
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if strings.HasPrefix(cb, "_") {
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return errors.New("disallowed callback method (starts with '_')")
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}
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if !ic.VM.AddGas(gas.Int64()) {
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return ErrNotEnoughGas
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}
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callingHash := ic.VM.GetCallingScriptHash()
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o.GAS.mint(ic, o.Hash, gas, false)
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si := ic.DAO.GetStorageItem(o.ID, prefixRequestID)
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itemID := bigint.FromBytes(si.Value)
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id := itemID.Uint64()
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itemID.Add(itemID, intOne)
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si.Value = bigint.ToPreallocatedBytes(itemID, si.Value)
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if err := ic.DAO.PutStorageItem(o.ID, prefixRequestID, si); err != nil {
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return err
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}
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// Should be executed from contract.
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_, err := ic.GetContract(ic.VM.GetCallingScriptHash())
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if err != nil {
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return err
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}
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w := io.NewBufBinWriter()
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stackitem.EncodeBinaryStackItem(userData, w.BinWriter)
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if w.Err != nil {
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return w.Err
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}
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data := w.Bytes()
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if len(data) > maxUserDataLength {
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return ErrBigArgument
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}
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var filterNotif stackitem.Item
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if filter != nil {
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filterNotif = stackitem.Make(*filter)
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} else {
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filterNotif = stackitem.Null{}
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}
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ic.Notifications = append(ic.Notifications, state.NotificationEvent{
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ScriptHash: o.Hash,
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Name: "OracleRequest",
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Item: stackitem.NewArray([]stackitem.Item{
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stackitem.Make(id),
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stackitem.Make(ic.VM.GetCallingScriptHash().BytesBE()),
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stackitem.Make(url),
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filterNotif,
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}),
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})
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req := &state.OracleRequest{
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OriginalTxID: o.getOriginalTxID(ic.DAO, ic.Tx),
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GasForResponse: gas.Uint64(),
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URL: url,
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Filter: filter,
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CallbackContract: callingHash,
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CallbackMethod: cb,
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UserData: data,
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}
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return o.PutRequestInternal(id, req, ic.DAO)
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}
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// PutRequestInternal puts oracle request with the specified id to d.
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func (o *Oracle) PutRequestInternal(id uint64, req *state.OracleRequest, d dao.DAO) error {
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reqItem := &state.StorageItem{Value: req.Bytes()}
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reqKey := makeRequestKey(id)
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if err := d.PutStorageItem(o.ID, reqKey, reqItem); err != nil {
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return err
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}
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o.newRequests[id] = req
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// Add request ID to the id list.
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lst := new(IDList)
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key := makeIDListKey(req.URL)
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if err := o.getSerializableFromDAO(d, key, lst); err != nil && !errors.Is(err, storage.ErrKeyNotFound) {
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return err
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}
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if len(*lst) >= maxRequestsCount {
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return fmt.Errorf("there are too many pending requests for %s url", req.URL)
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}
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*lst = append(*lst, id)
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si := &state.StorageItem{Value: lst.Bytes()}
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return d.PutStorageItem(o.ID, key, si)
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}
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// GetScriptHash returns script hash or oracle nodes.
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func (o *Oracle) GetScriptHash(d dao.DAO) (util.Uint160, error) {
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return o.Desig.GetLastDesignatedHash(d, RoleOracle)
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}
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// GetOracleNodes returns public keys of oracle nodes.
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func (o *Oracle) GetOracleNodes(d dao.DAO) (keys.PublicKeys, error) {
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nodes, _, err := o.Desig.GetDesignatedByRole(d, RoleOracle, math.MaxUint32)
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return nodes, err
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}
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// GetRequestInternal returns request by ID and key under which it is stored.
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func (o *Oracle) GetRequestInternal(d dao.DAO, id uint64) (*state.OracleRequest, error) {
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key := makeRequestKey(id)
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req := new(state.OracleRequest)
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return req, o.getSerializableFromDAO(d, key, req)
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}
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// GetIDListInternal returns request by ID and key under which it is stored.
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func (o *Oracle) GetIDListInternal(d dao.DAO, url string) (*IDList, error) {
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key := makeIDListKey(url)
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idList := new(IDList)
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return idList, o.getSerializableFromDAO(d, key, idList)
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}
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func (o *Oracle) verify(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
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return stackitem.NewBool(ic.Tx.HasAttribute(transaction.OracleResponseT))
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}
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func (o *Oracle) getOriginalTxID(d dao.DAO, tx *transaction.Transaction) util.Uint256 {
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for i := range tx.Attributes {
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if tx.Attributes[i].Type == transaction.OracleResponseT {
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id := tx.Attributes[i].Value.(*transaction.OracleResponse).ID
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req, _ := o.GetRequestInternal(d, id)
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return req.OriginalTxID
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}
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}
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return tx.Hash()
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}
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// getRequests returns all requests which have not been finished yet.
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func (o *Oracle) getRequests(d dao.DAO) (map[uint64]*state.OracleRequest, error) {
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m, err := d.GetStorageItemsWithPrefix(o.ID, prefixRequest)
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if err != nil {
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return nil, err
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}
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reqs := make(map[uint64]*state.OracleRequest, len(m))
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for k, si := range m {
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if len(k) != 8 {
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return nil, errors.New("invalid request ID")
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}
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r := io.NewBinReaderFromBuf(si.Value)
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req := new(state.OracleRequest)
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req.DecodeBinary(r)
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if r.Err != nil {
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return nil, r.Err
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}
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id := binary.BigEndian.Uint64([]byte(k))
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reqs[id] = req
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}
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return reqs, nil
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}
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func makeRequestKey(id uint64) []byte {
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k := make([]byte, 9)
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k[0] = prefixRequest[0]
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binary.BigEndian.PutUint64(k[1:], id)
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return k
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}
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func makeIDListKey(url string) []byte {
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return append(prefixIDList, hash.Hash160([]byte(url)).BytesBE()...)
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}
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func (o *Oracle) getSerializableFromDAO(d dao.DAO, key []byte, item io.Serializable) error {
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return getSerializableFromDAO(o.ID, d, key, item)
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}
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// updateCache updates cached Oracle values if they've been changed
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func (o *Oracle) updateCache(d dao.DAO) error {
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orc, _ := o.Module.Load().(services.Oracle)
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if orc == nil {
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return nil
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}
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reqs := o.newRequests
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o.newRequests = make(map[uint64]*state.OracleRequest)
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for id := range reqs {
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key := makeRequestKey(id)
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if si := d.GetStorageItem(o.ID, key); si == nil { // tx has failed
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delete(reqs, id)
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}
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}
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orc.AddRequests(reqs)
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return nil
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}
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