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package natspec
import (
"encoding/json"
"fmt"
"github.com/robertkrimen/otto"
"strings"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
)
type abi2method map[[8]byte]*method
type NatSpec struct {
jsvm *otto.Otto
methods abi2method
userDocJson, abiDocJson []byte
userDoc userDoc
// abiDoc abiDoc
}
// TODO: should initialise with abi and userdoc jsons
func New() (self *NatSpec, err error) {
// fetch abi, userdoc
abi := []byte("")
userdoc := []byte("")
return NewWithDocs(abi, userdoc)
}
func NewWithDocs(abiDocJson, userDocJson []byte) (self *NatSpec, err error) {
self = &NatSpec{
jsvm: otto.New(),
abiDocJson: abiDocJson,
userDocJson: userDocJson,
}
_, err = self.jsvm.Run(natspecJS)
if err != nil {
return
}
_, err = self.jsvm.Run("var natspec = require('natspec');")
if err != nil {
return
}
err = json.Unmarshal(userDocJson, &self.userDoc)
// err = parseAbiJson(abiDocJson, &self.abiDoc)
return
}
// type abiDoc []method
// type method struct {
// Name string `json:name`
// Inputs []input `json:inputs`
// abiKey [8]byte
// }
// type input struct {
// Name string `json:name`
// Type string `json:type`
// }
type method struct {
Notice string `json:notice`
name string
}
type userDoc struct {
Methods map[string]*method `json:methods`
}
func (self *NatSpec) makeAbi2method(abiKey [8]byte) (meth *method) {
if self.methods != nil {
meth = self.methods[abiKey]
return
}
self.methods = make(abi2method)
for signature, m := range self.userDoc.Methods {
name := strings.Split(signature, "(")[0]
hash := []byte(common.Bytes2Hex(crypto.Sha3([]byte(signature))))
var key [8]byte
copy(key[:], hash[:8])
self.methods[key] = meth
meth.name = name
if key == abiKey {
meth = m
}
}
return
}
func (self *NatSpec) Notice(tx string, abi string) (notice string, err error) {
var abiKey [8]byte
copy(abiKey[:], []byte(abi)[:8])
meth := self.makeAbi2method(abiKey)
if meth == nil {
err = fmt.Errorf("abi key %x does not match any method %v")
return
}
notice, err = self.noticeForMethod(tx, meth.name, meth.Notice)
return
}
func (self *NatSpec) noticeForMethod(tx string, name, expression string) (notice string, err error) {
if _, err = self.jsvm.Run("var transaction = " + tx + ";"); err != nil {
return "", fmt.Errorf("natspec.js error setting transaction: %v", err)
}
if _, err = self.jsvm.Run("var abi = " + string(self.abiDocJson) + ";"); err != nil {
return "", fmt.Errorf("natspec.js error setting abi: %v", err)
}
if _, err = self.jsvm.Run("var method = '" + name + "';"); err != nil {
return "", fmt.Errorf("natspec.js error setting method: %v", err)
}
if _, err = self.jsvm.Run("var expression = \"" + expression + "\";"); err != nil {
return "", fmt.Errorf("natspec.js error setting expression: %v", err)
}
self.jsvm.Run("var call = {method: method,abi: abi,transaction: transaction};")
value, err := self.jsvm.Run("natspec.evaluateExpression(expression, call);")
if err != nil {
return "", fmt.Errorf("natspec.js error evaluating expression: %v", err)
}
evalError := "Natspec evaluation failed, wrong input params"
if value.String() == evalError {
return "", fmt.Errorf("natspec.js error evaluating expression: wrong input params in expression '%s'", expression)
}
if len(value.String()) == 0 {
return "", fmt.Errorf("natspec.js error evaluating expression")
}
return value.String(), nil
}
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