577 lines
16 KiB
Go
577 lines
16 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/config"
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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/native/nativenames"
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"github.com/nspcc-dev/neo-go/pkg/core/native/noderoles"
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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/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/util/slice"
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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 the current block.
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newRequests map[uint64]*state.OracleRequest
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}
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type OracleCache struct {
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requestPrice int64
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}
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// OracleService specifies oracle module interface.
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type OracleService interface {
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// AddRequests processes new requests.
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AddRequests(map[uint64]*state.OracleRequest)
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// RemoveRequests removes already processed requests.
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RemoveRequests([]uint64)
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// UpdateOracleNodes updates oracle nodes.
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UpdateOracleNodes(keys.PublicKeys)
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// UpdateNativeContract updates oracle contract native script and hash.
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UpdateNativeContract([]byte, []byte, util.Uint160, int)
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// Start runs oracle module.
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Start()
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// Shutdown shutdowns oracle module.
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Shutdown()
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}
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const (
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oracleContractID = -9
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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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// DefaultOracleRequestPrice is the default amount GAS needed for an oracle request.
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DefaultOracleRequestPrice = 5000_0000
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// MinimumResponseGas is the minimum response fee permitted for a request.
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MinimumResponseGas = 10_000_000
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)
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var (
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prefixRequestPrice = []byte{5}
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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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ErrLowResponseGas = errors.New("not enough gas for response")
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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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var (
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_ interop.Contract = (*Oracle)(nil)
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_ dao.NativeContractCache = (*OracleCache)(nil)
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)
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// Copy implements NativeContractCache interface.
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func (c *OracleCache) Copy() dao.NativeContractCache {
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cp := &OracleCache{}
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copyOracleCache(c, cp)
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return cp
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}
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func copyOracleCache(src, dst *OracleCache) {
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*dst = *src
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}
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func newOracle() *Oracle {
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o := &Oracle{
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ContractMD: *interop.NewContractMD(nativenames.Oracle, oracleContractID),
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newRequests: make(map[uint64]*state.OracleRequest),
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}
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defer o.UpdateHash()
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o.oracleScript = CreateOracleResponseScript(o.Hash)
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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, 0, callflag.States|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.States|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, 1<<15, 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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desc = newDescriptor("getPrice", smartcontract.IntegerType)
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md = newMethodAndPrice(o.getPrice, 1<<15, callflag.ReadStates)
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o.AddMethod(md, desc)
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desc = newDescriptor("setPrice", smartcontract.VoidType,
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manifest.NewParameter("price", smartcontract.IntegerType))
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md = newMethodAndPrice(o.setPrice, 1<<15, callflag.States)
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o.AddMethod(md, desc)
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return o
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}
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// GetOracleResponseScript returns a script for the transaction with an oracle response.
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func (o *Oracle) GetOracleResponseScript() []byte {
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return slice.Copy(o.oracleScript)
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}
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// OnPersist implements the Contract interface.
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func (o *Oracle) OnPersist(ic *interop.Context) error {
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return nil
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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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p := o.getPriceInternal(ic.DAO)
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var nodes keys.PublicKeys
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var reward []big.Int
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single := big.NewInt(p)
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var removedIDs []uint64
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orc, _ := o.Module.Load().(*OracleService)
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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.getConvertibleFromDAO(ic.DAO, reqKey, req); err != nil {
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continue
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}
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ic.DAO.DeleteStorageItem(o.ID, reqKey)
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if orc != nil && *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.getConvertibleFromDAO(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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ic.DAO.DeleteStorageItem(o.ID, idKey)
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} else {
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err = putConvertibleToDAO(o.ID, ic.DAO, idKey, idList)
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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 {
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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 an Oracle contract.
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func (o *Oracle) Initialize(ic *interop.Context) error {
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setIntWithKey(o.ID, ic.DAO, prefixRequestID, 0)
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setIntWithKey(o.ID, ic.DAO, prefixRequestPrice, DefaultOracleRequestPrice)
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cache := &OracleCache{
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requestPrice: int64(DefaultOracleRequestPrice),
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}
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ic.DAO.SetCache(o.ID, cache)
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return nil
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}
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func (o *Oracle) InitializeCache(blockHeight uint32, d *dao.Simple) error {
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cache := &OracleCache{}
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cache.requestPrice = getIntWithKey(o.ID, d, prefixRequestPrice)
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d.SetCache(o.ID, cache)
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return nil
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}
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// ActiveIn implements the Contract interface.
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func (o *Oracle) ActiveIn() *config.Hardfork {
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return nil
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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 an oracle response.
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func (o *Oracle) FinishInternal(ic *interop.Context) error {
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if len(ic.VM.Istack()) != 2 {
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return errors.New("Oracle.finish called from non-entry script")
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}
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if ic.Invocations[o.Hash] != 1 {
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return errors.New("Oracle.finish called multiple times")
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}
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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.AddNotification(o.Hash, "OracleResponse", 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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origTx, _, err := ic.DAO.GetTransaction(req.OriginalTxID)
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if err != nil {
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return ErrRequestNotFound
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}
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ic.UseSigners(origTx.Signers)
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defer ic.UseSigners(nil)
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userData, err := stackitem.Deserialize(req.UserData)
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if err != nil {
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return err
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}
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args := []stackitem.Item{
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stackitem.Make(req.URL),
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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 !ic.VM.AddGas(o.getPriceInternal(ic.DAO)) {
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panic("insufficient gas")
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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 an 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.IsInt64() {
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return ErrBigArgument
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}
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if gas.Int64() < MinimumResponseGas {
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return ErrLowResponseGas
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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)
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id := itemID.Uint64()
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itemID.Add(itemID, intOne)
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ic.DAO.PutBigInt(o.ID, prefixRequestID, itemID)
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// Should be executed from the 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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data, err := ic.DAO.GetItemCtx().Serialize(userData, false)
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if err != nil {
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return err
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}
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if len(data) > maxUserDataLength {
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return ErrBigArgument
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}
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data = slice.Copy(data) // Serialization context will be used in PutRequestInternal again.
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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.AddNotification(o.Hash, "OracleRequest", 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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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 the oracle request with the specified id to d.
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func (o *Oracle) PutRequestInternal(id uint64, req *state.OracleRequest, d *dao.Simple) error {
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reqKey := makeRequestKey(id)
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if err := putConvertibleToDAO(o.ID, d, reqKey, req); err != nil {
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return err
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}
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orc, _ := o.Module.Load().(*OracleService)
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if orc != nil && *orc != nil {
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o.newRequests[id] = req
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}
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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.getConvertibleFromDAO(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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return putConvertibleToDAO(o.ID, d, key, lst)
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}
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// GetScriptHash returns script hash of oracle nodes.
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func (o *Oracle) GetScriptHash(d *dao.Simple) (util.Uint160, error) {
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return o.Desig.GetLastDesignatedHash(d, noderoles.Oracle)
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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.Simple) (keys.PublicKeys, error) {
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nodes, _, err := o.Desig.GetDesignatedByRole(d, noderoles.Oracle, math.MaxUint32)
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return nodes, err
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}
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// GetRequestInternal returns the request by ID and key under which it is stored.
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func (o *Oracle) GetRequestInternal(d *dao.Simple, 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.getConvertibleFromDAO(d, key, req)
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}
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// GetIDListInternal returns the request by ID and key under which it is stored.
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func (o *Oracle) GetIDListInternal(d *dao.Simple, 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.getConvertibleFromDAO(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) getPrice(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
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return stackitem.NewBigInteger(big.NewInt(o.getPriceInternal(ic.DAO)))
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}
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func (o *Oracle) getPriceInternal(d *dao.Simple) int64 {
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cache := d.GetROCache(o.ID).(*OracleCache)
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return cache.requestPrice
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}
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func (o *Oracle) setPrice(ic *interop.Context, args []stackitem.Item) stackitem.Item {
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price := toBigInt(args[0])
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if price.Sign() <= 0 || !price.IsInt64() {
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panic("invalid register price")
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}
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if !o.NEO.checkCommittee(ic) {
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panic("invalid committee signature")
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}
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setIntWithKey(o.ID, ic.DAO, prefixRequestPrice, price.Int64())
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cache := ic.DAO.GetRWCache(o.ID).(*OracleCache)
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cache.requestPrice = price.Int64()
|
|
return stackitem.Null{}
|
|
}
|
|
|
|
func (o *Oracle) getOriginalTxID(d *dao.Simple, tx *transaction.Transaction) util.Uint256 {
|
|
for i := range tx.Attributes {
|
|
if tx.Attributes[i].Type == transaction.OracleResponseT {
|
|
id := tx.Attributes[i].Value.(*transaction.OracleResponse).ID
|
|
req, _ := o.GetRequestInternal(d, id)
|
|
return req.OriginalTxID
|
|
}
|
|
}
|
|
return tx.Hash()
|
|
}
|
|
|
|
// GetRequests returns all requests which have not been finished yet.
|
|
func (o *Oracle) GetRequests(d *dao.Simple) (map[uint64]*state.OracleRequest, error) {
|
|
var reqs = make(map[uint64]*state.OracleRequest)
|
|
var err error
|
|
d.Seek(o.ID, storage.SeekRange{Prefix: prefixRequest}, func(k, v []byte) bool {
|
|
if len(k) != 8 {
|
|
err = errors.New("invalid request ID")
|
|
return false
|
|
}
|
|
req := new(state.OracleRequest)
|
|
err = stackitem.DeserializeConvertible(v, req)
|
|
if err != nil {
|
|
return false
|
|
}
|
|
id := binary.BigEndian.Uint64(k)
|
|
reqs[id] = req
|
|
return true
|
|
})
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return reqs, nil
|
|
}
|
|
|
|
func makeRequestKey(id uint64) []byte {
|
|
k := make([]byte, 9)
|
|
k[0] = prefixRequest[0]
|
|
binary.BigEndian.PutUint64(k[1:], id)
|
|
return k
|
|
}
|
|
|
|
func makeIDListKey(url string) []byte {
|
|
return append(prefixIDList, hash.Hash160([]byte(url)).BytesBE()...)
|
|
}
|
|
|
|
func (o *Oracle) getConvertibleFromDAO(d *dao.Simple, key []byte, item stackitem.Convertible) error {
|
|
return getConvertibleFromDAO(o.ID, d, key, item)
|
|
}
|
|
|
|
// updateCache updates cached Oracle values if they've been changed.
|
|
func (o *Oracle) updateCache(d *dao.Simple) error {
|
|
orc, _ := o.Module.Load().(*OracleService)
|
|
if orc == nil || *orc == nil {
|
|
return nil
|
|
}
|
|
|
|
reqs := o.newRequests
|
|
o.newRequests = make(map[uint64]*state.OracleRequest)
|
|
for id := range reqs {
|
|
key := makeRequestKey(id)
|
|
if si := d.GetStorageItem(o.ID, key); si == nil { // tx has failed
|
|
delete(reqs, id)
|
|
}
|
|
}
|
|
(*orc).AddRequests(reqs)
|
|
return nil
|
|
}
|
|
|
|
// CreateOracleResponseScript returns a script that is used to create the native Oracle
|
|
// response.
|
|
func CreateOracleResponseScript(nativeOracleHash util.Uint160) []byte {
|
|
script, err := smartcontract.CreateCallScript(nativeOracleHash, "finish")
|
|
if err != nil {
|
|
panic(fmt.Errorf("failed to create Oracle response script: %w", err))
|
|
}
|
|
return script
|
|
}
|