// 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"
"go/format"
"regexp"
"strings"
"text/template"
"unicode"
"github.com/ethereum/go-ethereum/accounts/abi"
)
// 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; events; and sort them alphabetically
var (
calls = make(map[string]*tmplMethod)
transacts = make(map[string]*tmplMethod)
events = make(map[string]*tmplEvent)
)
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.Outputs)}
} else {
transacts[original.Name] = &tmplMethod{Original: original, Normalized: normalized, Structured: structured(original.Outputs)}
}
}
for _, original := range evmABI.Events {
// Skip anonymous events as they don't support explicit filtering
if original.Anonymous {
continue
}
// Normalize the event for capital cases and non-anonymous 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 {
// Indexed fields are input, non-indexed ones are outputs
if input.Indexed {
if input.Name == "" {
normalized.Inputs[j].Name = fmt.Sprintf("arg%d", j)
}
}
}
// Append the event to the accumulator list
events[original.Name] = &tmplEvent{Original: original, Normalized: normalized}
}
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,
Events: events,
}
}
// 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],
"bindtopictype": bindTopicType[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 gofmt to clean it up
if lang == LangGo {
code, err := format.Source(buffer.Bytes())
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 buffer.String(), nil
}
// bindType is a set of type binders that convert Solidity types to some supported
// programming language types.
var bindType = map[Lang]func(kind abi.Type) string{
LangGo: bindTypeGo,
LangJava: bindTypeJava,
}
// Helper function for the binding generators.
// It reads the unmatched characters after the inner type-match,
// (since the inner type is a prefix of the total type declaration),
// looks for valid arrays (possibly a dynamic one) wrapping the inner type,
// and returns the sizes of these arrays.
//
// Returned array sizes are in the same order as solidity signatures; inner array size first.
// Array sizes may also be "", indicating a dynamic array.
func wrapArray(stringKind string, innerLen int, innerMapping string) (string, []string) {
remainder := stringKind[innerLen:]
//find all the sizes
matches := regexp.MustCompile(`\[(\d*)\]`).FindAllStringSubmatch(remainder, -1)
parts := make([]string, 0, len(matches))
for _, match := range matches {
//get group 1 from the regex match
parts = append(parts, match[1])
}
return innerMapping, parts
}
// Translates the array sizes to a Go-lang declaration of a (nested) array of the inner type.
// Simply returns the inner type if arraySizes is empty.
func arrayBindingGo(inner string, arraySizes []string) string {
out := ""
//prepend all array sizes, from outer (end arraySizes) to inner (start arraySizes)
for i := len(arraySizes) - 1; i >= 0; i-- {
out += "[" + arraySizes[i] + "]"
}
out += inner
return out
}
// 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()
innerLen, innerMapping := bindUnnestedTypeGo(stringKind)
return arrayBindingGo(wrapArray(stringKind, innerLen, innerMapping))
}
// The inner function of bindTypeGo, this finds the inner type of stringKind.
// (Or just the type itself if it is not an array or slice)
// The length of the matched part is returned, with the translated type.
func bindUnnestedTypeGo(stringKind string) (int, string) {
switch {
case strings.HasPrefix(stringKind, "address"):
return len("address"), "common.Address"
case strings.HasPrefix(stringKind, "bytes"):
parts := regexp.MustCompile(`bytes([0-9]*)`).FindStringSubmatch(stringKind)
return len(parts[0]), fmt.Sprintf("[%s]byte", parts[1])
case strings.HasPrefix(stringKind, "int") || strings.HasPrefix(stringKind, "uint"):
parts := regexp.MustCompile(`(u)?int([0-9]*)`).FindStringSubmatch(stringKind)
switch parts[2] {
case "8", "16", "32", "64":
return len(parts[0]), fmt.Sprintf("%sint%s", parts[1], parts[2])
}
return len(parts[0]), "*big.Int"
case strings.HasPrefix(stringKind, "bool"):
return len("bool"), "bool"
case strings.HasPrefix(stringKind, "string"):
return len("string"), "string"
default:
return len(stringKind), stringKind
}
}
// Translates the array sizes to a Java declaration of a (nested) array of the inner type.
// Simply returns the inner type if arraySizes is empty.
func arrayBindingJava(inner string, arraySizes []string) string {
// Java array type declarations do not include the length.
return inner + strings.Repeat("[]", len(arraySizes))
}
// 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()
innerLen, innerMapping := bindUnnestedTypeJava(stringKind)
return arrayBindingJava(wrapArray(stringKind, innerLen, innerMapping))
}
// The inner function of bindTypeJava, this finds the inner type of stringKind.
// (Or just the type itself if it is not an array or slice)
// The length of the matched part is returned, with the translated type.
func bindUnnestedTypeJava(stringKind string) (int, string) {
switch {
case strings.HasPrefix(stringKind, "address"):
parts := regexp.MustCompile(`address(\[[0-9]*\])?`).FindStringSubmatch(stringKind)
if len(parts) != 2 {
return len(stringKind), stringKind
}
if parts[1] == "" {
return len("address"), "Address"
}
return len(parts[0]), "Addresses"
case strings.HasPrefix(stringKind, "bytes"):
parts := regexp.MustCompile(`bytes([0-9]*)`).FindStringSubmatch(stringKind)
if len(parts) != 2 {
return len(stringKind), stringKind
}
return len(parts[0]), "byte[]"
case strings.HasPrefix(stringKind, "int") || strings.HasPrefix(stringKind, "uint"):
//Note that uint and int (without digits) are also matched,
// these are size 256, and will translate to BigInt (the default).
parts := regexp.MustCompile(`(u)?int([0-9]*)`).FindStringSubmatch(stringKind)
if len(parts) != 3 {
return len(stringKind), stringKind
}
namedSize := map[string]string{
"8": "byte",
"16": "short",
"32": "int",
"64": "long",
}[parts[2]]
//default to BigInt
if namedSize == "" {
namedSize = "BigInt"
}
return len(parts[0]), namedSize
case strings.HasPrefix(stringKind, "bool"):
return len("bool"), "boolean"
case strings.HasPrefix(stringKind, "string"):
return len("string"), "String"
default:
return len(stringKind), stringKind
}
}
// bindTopicType is a set of type binders that convert Solidity types to some
// supported programming language topic types.
var bindTopicType = map[Lang]func(kind abi.Type) string{
LangGo: bindTopicTypeGo,
LangJava: bindTopicTypeJava,
}
// bindTypeGo converts a Solidity topic type to a Go one. It is almost the same
// funcionality as for simple types, but dynamic types get converted to hashes.
func bindTopicTypeGo(kind abi.Type) string {
bound := bindTypeGo(kind)
if bound == "string" || bound == "[]byte" {
bound = "common.Hash"
}
return bound
}
// bindTypeGo converts a Solidity topic type to a Java one. It is almost the same
// funcionality as for simple types, but dynamic types get converted to hashes.
func bindTopicTypeJava(kind abi.Type) string {
bound := bindTypeJava(kind)
if bound == "String" || bound == "Bytes" {
bound = "Hash"
}
return bound
}
// 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 "boolean":
return "Bool"
case "boolean[]":
return "Bools"
case "BigInt[]":
return "BigInts"
default:
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
}
}
}
// 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 a camel-case string which starts with an upper case character.
func capitalise(input string) string {
for len(input) > 0 && input[0] == '_' {
input = input[1:]
}
if len(input) == 0 {
return ""
}
return toCamelCase(strings.ToUpper(input[:1]) + input[1:])
}
// decapitalise makes a camel-case string which starts with a lower case character.
func decapitalise(input string) string {
for len(input) > 0 && input[0] == '_' {
input = input[1:]
}
if len(input) == 0 {
return ""
}
return toCamelCase(strings.ToLower(input[:1]) + input[1:])
}
// toCamelCase converts an under-score string to a camel-case string
func toCamelCase(input string) string {
toupper := false
result := ""
for k, v := range input {
switch {
case k == 0:
result = strings.ToUpper(string(input[0]))
case toupper:
result += strings.ToUpper(string(v))
toupper = false
case v == '_':
toupper = true
default:
result += string(v)
}
}
return result
}
// structured checks whether a list of ABI data types has enough information to
// operate through a proper Go struct or if flat returns are needed.
func structured(args abi.Arguments) bool {
if len(args) < 2 {
return false
}
exists := make(map[string]bool)
for _, out := range args {
// If the name is anonymous, we can't organize into a struct
if out.Name == "" {
return false
}
// If the field name is empty when normalized or collides (var, Var, _var, _Var),
// we can't organize into a struct
field := capitalise(out.Name)
if field == "" || exists[field] {
return false
}
exists[field] = true
}
return true
}