// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
// Package bind generates Ethereum contract Go bindings.
//
// Detailed usage document and tutorial available on the go-ethereum Wiki page:
// https://github.com/ethereum/go-ethereum/wiki/Native-DApps:-Go-bindings-to-Ethereum-contracts
package bind
import (
"bytes"
"fmt"
"regexp"
"strings"
"text/template"
"unicode"
"github.com/ethereum/go-ethereum/accounts/abi"
"golang.org/x/tools/imports"
)
// Lang is a target programming language selector to generate bindings for.
type Lang int
const (
LangGo Lang = iota
LangJava
LangObjC
)
// Bind generates a Go wrapper around a contract ABI. This wrapper isn't meant
// to be used as is in client code, but rather as an intermediate struct which
// enforces compile time type safety and naming convention opposed to having to
// manually maintain hard coded strings that break on runtime.
func Bind(types []string, abis []string, bytecodes []string, pkg string, lang Lang) (string, error) {
// Process each individual contract requested binding
contracts := make(map[string]*tmplContract)
for i := 0; i < len(types); i++ {
// Parse the actual ABI to generate the binding for
evmABI, err := abi.JSON(strings.NewReader(abis[i]))
if err != nil {
return "", err
}
// Strip any whitespace from the JSON ABI
strippedABI := strings.Map(func(r rune) rune {
if unicode.IsSpace(r) {
return -1
}
return r
}, abis[i])
// Extract the call and transact methods, and sort them alphabetically
var (
calls = make(map[string]*tmplMethod)
transacts = make(map[string]*tmplMethod)
)
for _, original := range evmABI.Methods {
// Normalize the method for capital cases and non-anonymous inputs/outputs
normalized := original
normalized.Name = methodNormalizer[lang](original.Name)
normalized.Inputs = make([]abi.Argument, len(original.Inputs))
copy(normalized.Inputs, original.Inputs)
for j, input := range normalized.Inputs {
if input.Name == "" {
normalized.Inputs[j].Name = fmt.Sprintf("arg%d", j)
}
}
normalized.Outputs = make([]abi.Argument, len(original.Outputs))
copy(normalized.Outputs, original.Outputs)
for j, output := range normalized.Outputs {
if output.Name != "" {
normalized.Outputs[j].Name = capitalise(output.Name)
}
}
// Append the methods to the call or transact lists
if original.Const {
calls[original.Name] = &tmplMethod{Original: original, Normalized: normalized, Structured: structured(original)}
} else {
transacts[original.Name] = &tmplMethod{Original: original, Normalized: normalized, Structured: structured(original)}
}
}
contracts[types[i]] = &tmplContract{
Type: capitalise(types[i]),
InputABI: strings.Replace(strippedABI, "\"", "\\\"", -1),
InputBin: strings.TrimSpace(bytecodes[i]),
Constructor: evmABI.Constructor,
Calls: calls,
Transacts: transacts,
}
}
// Generate the contract template data content and render it
data := &tmplData{
Package: pkg,
Contracts: contracts,
}
buffer := new(bytes.Buffer)
funcs := map[string]interface{}{
"bindtype": bindType[lang],
"namedtype": namedType[lang],
"capitalise": capitalise,
"decapitalise": decapitalise,
}
tmpl := template.Must(template.New("").Funcs(funcs).Parse(tmplSource[lang]))
if err := tmpl.Execute(buffer, data); err != nil {
return "", err
}
// For Go bindings pass the code through goimports to clean it up and double check
if lang == LangGo {
code, err := imports.Process("", buffer.Bytes(), nil)
if err != nil {
return "", fmt.Errorf("%v\n%s", err, buffer)
}
return string(code), nil
}
// For all others just return as is for now
return string(buffer.Bytes()), nil
}
// bindType is a set of type binders that convert Solidity types to some supported
// programming language.
var bindType = map[Lang]func(kind abi.Type) string{
LangGo: bindTypeGo,
LangJava: bindTypeJava,
}
// bindTypeGo converts a Solidity type to a Go one. Since there is no clear mapping
// from all Solidity types to Go ones (e.g. uint17), those that cannot be exactly
// mapped will use an upscaled type (e.g. *big.Int).
func bindTypeGo(kind abi.Type) string {
stringKind := kind.String()
switch {
case strings.HasPrefix(stringKind, "address"):
parts := regexp.MustCompile(`address(\[[0-9]*\])?`).FindStringSubmatch(stringKind)
if len(parts) != 2 {
return stringKind
}
return fmt.Sprintf("%scommon.Address", parts[1])
case strings.HasPrefix(stringKind, "bytes"):
parts := regexp.MustCompile(`bytes([0-9]*)(\[[0-9]*\])?`).FindStringSubmatch(stringKind)
if len(parts) != 3 {
return stringKind
}
return fmt.Sprintf("%s[%s]byte", parts[2], parts[1])
case strings.HasPrefix(stringKind, "int") || strings.HasPrefix(stringKind, "uint"):
parts := regexp.MustCompile(`(u)?int([0-9]*)(\[[0-9]*\])?`).FindStringSubmatch(stringKind)
if len(parts) != 4 {
return stringKind
}
switch parts[2] {
case "8", "16", "32", "64":
return fmt.Sprintf("%s%sint%s", parts[3], parts[1], parts[2])
}
return fmt.Sprintf("%s*big.Int", parts[3])
case strings.HasPrefix(stringKind, "bool") || strings.HasPrefix(stringKind, "string"):
parts := regexp.MustCompile(`([a-z]+)(\[[0-9]*\])?`).FindStringSubmatch(stringKind)
if len(parts) != 3 {
return stringKind
}
return fmt.Sprintf("%s%s", parts[2], parts[1])
default:
return stringKind
}
}
// bindTypeJava converts a Solidity type to a Java one. Since there is no clear mapping
// from all Solidity types to Java ones (e.g. uint17), those that cannot be exactly
// mapped will use an upscaled type (e.g. BigDecimal).
func bindTypeJava(kind abi.Type) string {
stringKind := kind.String()
switch {
case strings.HasPrefix(stringKind, "address"):
parts := regexp.MustCompile(`address(\[[0-9]*\])?`).FindStringSubmatch(stringKind)
if len(parts) != 2 {
return stringKind
}
if parts[1] == "" {
return fmt.Sprintf("Address")
}
return fmt.Sprintf("Addresses")
case strings.HasPrefix(stringKind, "bytes"):
parts := regexp.MustCompile(`bytes([0-9]*)(\[[0-9]*\])?`).FindStringSubmatch(stringKind)
if len(parts) != 3 {
return stringKind
}
if parts[2] != "" {
return "byte[][]"
}
return "byte[]"
case strings.HasPrefix(stringKind, "int") || strings.HasPrefix(stringKind, "uint"):
parts := regexp.MustCompile(`(u)?int([0-9]*)(\[[0-9]*\])?`).FindStringSubmatch(stringKind)
if len(parts) != 4 {
return stringKind
}
switch parts[2] {
case "8", "16", "32", "64":
if parts[1] == "" {
if parts[3] == "" {
return fmt.Sprintf("int%s", parts[2])
}
return fmt.Sprintf("int%s[]", parts[2])
}
}
if parts[3] == "" {
return fmt.Sprintf("BigInt")
}
return fmt.Sprintf("BigInts")
case strings.HasPrefix(stringKind, "bool"):
parts := regexp.MustCompile(`bool(\[[0-9]*\])?`).FindStringSubmatch(stringKind)
if len(parts) != 2 {
return stringKind
}
if parts[1] == "" {
return fmt.Sprintf("bool")
}
return fmt.Sprintf("bool[]")
case strings.HasPrefix(stringKind, "string"):
parts := regexp.MustCompile(`string(\[[0-9]*\])?`).FindStringSubmatch(stringKind)
if len(parts) != 2 {
return stringKind
}
if parts[1] == "" {
return fmt.Sprintf("String")
}
return fmt.Sprintf("String[]")
default:
return stringKind
}
}
// namedType is a set of functions that transform language specific types to
// named versions that my be used inside method names.
var namedType = map[Lang]func(string, abi.Type) string{
LangGo: func(string, abi.Type) string { panic("this shouldn't be needed") },
LangJava: namedTypeJava,
}
// namedTypeJava converts some primitive data types to named variants that can
// be used as parts of method names.
func namedTypeJava(javaKind string, solKind abi.Type) string {
switch javaKind {
case "byte[]":
return "Binary"
case "byte[][]":
return "Binaries"
case "string":
return "String"
case "string[]":
return "Strings"
case "bool":
return "Bool"
case "bool[]":
return "Bools"
case "BigInt":
parts := regexp.MustCompile(`(u)?int([0-9]*)(\[[0-9]*\])?`).FindStringSubmatch(solKind.String())
if len(parts) != 4 {
return javaKind
}
switch parts[2] {
case "8", "16", "32", "64":
if parts[3] == "" {
return capitalise(fmt.Sprintf("%sint%s", parts[1], parts[2]))
}
return capitalise(fmt.Sprintf("%sint%ss", parts[1], parts[2]))
default:
return javaKind
}
default:
return javaKind
}
}
// methodNormalizer is a name transformer that modifies Solidity method names to
// conform to target language naming concentions.
var methodNormalizer = map[Lang]func(string) string{
LangGo: capitalise,
LangJava: decapitalise,
}
// capitalise makes the first character of a string upper case.
func capitalise(input string) string {
return strings.ToUpper(input[:1]) + input[1:]
}
// decapitalise makes the first character of a string lower case.
func decapitalise(input string) string {
return strings.ToLower(input[:1]) + input[1:]
}
// structured checks whether a method has enough information to return a proper
// Go struct ot if flat returns are needed.
func structured(method abi.Method) bool {
if len(method.Outputs) < 2 {
return false
}
for _, out := range method.Outputs {
if out.Name == "" {
return false
}
}
return true
}
