261 lines
7.0 KiB
Go
261 lines
7.0 KiB
Go
// Copyright 2015 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// go-ethereum is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package natspec
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import (
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"bytes"
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"encoding/json"
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"fmt"
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"strings"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/common/docserver"
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"github.com/ethereum/go-ethereum/common/registrar"
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"github.com/ethereum/go-ethereum/crypto"
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"github.com/ethereum/go-ethereum/xeth"
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"github.com/robertkrimen/otto"
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)
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type abi2method map[[8]byte]*method
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type NatSpec struct {
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jsvm *otto.Otto
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abiDocJson []byte
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userDoc userDoc
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tx, data string
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}
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// main entry point for to get natspec notice for a transaction
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// the implementation is frontend friendly in that it always gives back
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// a notice that is safe to display
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// :FIXME: the second return value is an error, which can be used to fine-tune bahaviour
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func GetNotice(xeth *xeth.XEth, tx string, http *docserver.DocServer) (notice string) {
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ns, err := New(xeth, tx, http)
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if err != nil {
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if ns == nil {
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return getFallbackNotice(fmt.Sprintf("no NatSpec info found for contract: %v", err), tx)
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} else {
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return getFallbackNotice(fmt.Sprintf("invalid NatSpec info: %v", err), tx)
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}
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}
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notice, err = ns.Notice()
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if err != nil {
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return getFallbackNotice(fmt.Sprintf("NatSpec notice error: %v", err), tx)
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}
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return
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}
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func getFallbackNotice(comment, tx string) string {
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return fmt.Sprintf("About to submit transaction (%s): %s", comment, tx)
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}
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type transaction struct {
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To string `json:"to"`
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Data string `json:"data"`
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}
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type jsonTx struct {
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Params []transaction `json:"params"`
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}
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type contractInfo struct {
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Source string `json:"source"`
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Language string `json:"language"`
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Version string `json:"compilerVersion"`
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AbiDefinition json.RawMessage `json:"abiDefinition"`
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UserDoc userDoc `json:"userDoc"`
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DeveloperDoc json.RawMessage `json:"developerDoc"`
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}
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func New(xeth *xeth.XEth, jsontx string, http *docserver.DocServer) (self *NatSpec, err error) {
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// extract contract address from tx
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var tx jsonTx
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err = json.Unmarshal([]byte(jsontx), &tx)
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if err != nil {
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return
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}
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t := tx.Params[0]
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contractAddress := t.To
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content, err := FetchDocsForContract(contractAddress, xeth, http)
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if err != nil {
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return
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}
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self, err = NewWithDocs(content, jsontx, t.Data)
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return
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}
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// also called by admin.contractInfo.get
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func FetchDocsForContract(contractAddress string, xeth *xeth.XEth, ds *docserver.DocServer) (content []byte, err error) {
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// retrieve contract hash from state
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codehex := xeth.CodeAt(contractAddress)
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codeb := xeth.CodeAtBytes(contractAddress)
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if codehex == "0x" {
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err = fmt.Errorf("contract (%v) not found", contractAddress)
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return
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}
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codehash := common.BytesToHash(crypto.Sha3(codeb))
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// set up nameresolver with natspecreg + urlhint contract addresses
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reg := registrar.New(xeth)
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// resolve host via HashReg/UrlHint Resolver
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hash, err := reg.HashToHash(codehash)
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if err != nil {
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return
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}
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if ds.HasScheme("bzz") {
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content, err = ds.Get("bzz://"+hash.Hex()[2:], "")
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if err == nil { // non-fatal
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return
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}
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err = nil
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//falling back to urlhint
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}
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uri, err := reg.HashToUrl(hash)
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if err != nil {
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return
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}
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// get content via http client and authenticate content using hash
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content, err = ds.GetAuthContent(uri, hash)
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if err != nil {
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return
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}
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return
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}
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func NewWithDocs(infoDoc []byte, tx string, data string) (self *NatSpec, err error) {
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var contract contractInfo
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err = json.Unmarshal(infoDoc, &contract)
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if err != nil {
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return
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}
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self = &NatSpec{
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jsvm: otto.New(),
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abiDocJson: []byte(contract.AbiDefinition),
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userDoc: contract.UserDoc,
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tx: tx,
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data: data,
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}
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// load and require natspec js (but it is meant to be protected environment)
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_, err = self.jsvm.Run(natspecJS)
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if err != nil {
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return
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}
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_, err = self.jsvm.Run("var natspec = require('natspec');")
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return
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}
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// type abiDoc []method
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// type method struct {
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// Name string `json:name`
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// Inputs []input `json:inputs`
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// abiKey [8]byte
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// }
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// type input struct {
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// Name string `json:name`
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// Type string `json:type`
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// }
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// json skeleton for abi doc (contract method definitions)
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type method struct {
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Notice string `json:notice`
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name string
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}
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type userDoc struct {
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Methods map[string]*method `json:methods`
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}
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func (self *NatSpec) makeAbi2method(abiKey [8]byte) (meth *method) {
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for signature, m := range self.userDoc.Methods {
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name := strings.Split(signature, "(")[0]
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hash := []byte(common.Bytes2Hex(crypto.Sha3([]byte(signature))))
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var key [8]byte
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copy(key[:], hash[:8])
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if bytes.Equal(key[:], abiKey[:]) {
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meth = m
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meth.name = name
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return
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}
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}
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return
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}
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func (self *NatSpec) Notice() (notice string, err error) {
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var abiKey [8]byte
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if len(self.data) < 10 {
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err = fmt.Errorf("Invalid transaction data")
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return
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}
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copy(abiKey[:], self.data[2:10])
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meth := self.makeAbi2method(abiKey)
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if meth == nil {
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err = fmt.Errorf("abi key does not match any method")
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return
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}
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notice, err = self.noticeForMethod(self.tx, meth.name, meth.Notice)
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return
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}
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func (self *NatSpec) noticeForMethod(tx string, name, expression string) (notice string, err error) {
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if _, err = self.jsvm.Run("var transaction = " + tx + ";"); err != nil {
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return "", fmt.Errorf("natspec.js error setting transaction: %v", err)
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}
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if _, err = self.jsvm.Run("var abi = " + string(self.abiDocJson) + ";"); err != nil {
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return "", fmt.Errorf("natspec.js error setting abi: %v", err)
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}
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if _, err = self.jsvm.Run("var method = '" + name + "';"); err != nil {
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return "", fmt.Errorf("natspec.js error setting method: %v", err)
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}
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if _, err = self.jsvm.Run("var expression = \"" + expression + "\";"); err != nil {
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return "", fmt.Errorf("natspec.js error setting expression: %v", err)
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}
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self.jsvm.Run("var call = {method: method,abi: abi,transaction: transaction};")
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value, err := self.jsvm.Run("natspec.evaluateExpression(expression, call);")
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if err != nil {
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return "", fmt.Errorf("natspec.js error evaluating expression: %v", err)
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}
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evalError := "Natspec evaluation failed, wrong input params"
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if value.String() == evalError {
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return "", fmt.Errorf("natspec.js error evaluating expression: wrong input params in expression '%s'", expression)
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}
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if len(value.String()) == 0 {
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return "", fmt.Errorf("natspec.js error evaluating expression")
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}
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return value.String(), nil
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}
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