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bind.go
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bind.go
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// 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/simongcoin/go-simongdiuma/wiki/Native-DApps:-Go-bindings-to-Ethereum-contracts
package bind
import (
"bytes"
"errors"
"fmt"
"go/format"
"regexp"
"strings"
"text/template"
"unicode"
"github.com/simongcoin/go-simongdiuma/accounts/abi"
"github.com/simongcoin/go-simongdiuma/log"
)
// 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, fsigs []map[string]string, pkg string, lang Lang, libs map[string]string) (string, error) {
// Process each individual contract requested binding
contracts := make(map[string]*tmplContract)
// Map used to flag each encountered library as such
isLib := make(map[string]struct{})
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, struct definitions; and sort them alphabetically
var (
calls = make(map[string]*tmplMethod)
transacts = make(map[string]*tmplMethod)
events = make(map[string]*tmplEvent)
structs = make(map[string]*tmplStruct)
)
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)
}
if _, exist := structs[input.Type.String()]; input.Type.T == abi.TupleTy && !exist {
bindStructType[lang](input.Type, structs)
}
}
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)
}
if _, exist := structs[output.Type.String()]; output.Type.T == abi.TupleTy && !exist {
bindStructType[lang](output.Type, structs)
}
}
// 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)
}
if _, exist := structs[input.Type.String()]; input.Type.T == abi.TupleTy && !exist {
bindStructType[lang](input.Type, structs)
}
}
}
// Append the event to the accumulator list
events[original.Name] = &tmplEvent{Original: original, Normalized: normalized}
}
// There is no easy way to pass arbitrary java objects to the Go side.
if len(structs) > 0 && lang == LangJava {
return "", errors.New("java binding for tuple arguments is not supported yet")
}
contracts[types[i]] = &tmplContract{
Type: capitalise(types[i]),
InputABI: strings.Replace(strippedABI, "\"", "\\\"", -1),
InputBin: strings.TrimPrefix(strings.TrimSpace(bytecodes[i]), "0x"),
Constructor: evmABI.Constructor,
Calls: calls,
Transacts: transacts,
Events: events,
Libraries: make(map[string]string),
Structs: structs,
}
// Function 4-byte signatures are stored in the same sequence
// as types, if available.
if len(fsigs) > i {
contracts[types[i]].FuncSigs = fsigs[i]
}
// Parse library references.
for pattern, name := range libs {
matched, err := regexp.Match("__\\$"+pattern+"\\$__", []byte(contracts[types[i]].InputBin))
if err != nil {
log.Error("Could not search for pattern", "pattern", pattern, "contract", contracts[types[i]], "err", err)
}
if matched {
contracts[types[i]].Libraries[pattern] = name
// keep track that this type is a library
if _, ok := isLib[name]; !ok {
isLib[name] = struct{}{}
}
}
}
}
// Check if that type has already been identified as a library
for i := 0; i < len(types); i++ {
_, ok := isLib[types[i]]
contracts[types[i]].Library = ok
}
// Generate the contract template data content and render it
data := &tmplData{
Package: pkg,
Contracts: contracts,
Libraries: libs,
}
buffer := new(bytes.Buffer)
funcs := map[string]interface{}{
"bindtype": bindType[lang],
"bindtopictype": bindTopicType[lang],
"namedtype": namedType[lang],
"formatmethod": formatMethod,
"formatevent": formatEvent,
"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, structs map[string]*tmplStruct) string{
LangGo: bindTypeGo,
LangJava: bindTypeJava,
}
// bindBasicTypeGo converts basic solidity types(except array, slice and tuple) to Go one.
func bindBasicTypeGo(kind abi.Type) string {
switch kind.T {
case abi.AddressTy:
return "common.Address"
case abi.IntTy, abi.UintTy:
parts := regexp.MustCompile(`(u)?int([0-9]*)`).FindStringSubmatch(kind.String())
switch parts[2] {
case "8", "16", "32", "64":
return fmt.Sprintf("%sint%s", parts[1], parts[2])
}
return "*big.Int"
case abi.FixedBytesTy:
return fmt.Sprintf("[%d]byte", kind.Size)
case abi.BytesTy:
return "[]byte"
case abi.FunctionTy:
return "[24]byte"
default:
// string, bool types
return kind.String()
}
}
// bindTypeGo converts solidity types to Go ones. 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. BigDecimal).
func bindTypeGo(kind abi.Type, structs map[string]*tmplStruct) string {
switch kind.T {
case abi.TupleTy:
return structs[kind.String()].Name
case abi.ArrayTy:
return fmt.Sprintf("[%d]", kind.Size) + bindTypeGo(*kind.Elem, structs)
case abi.SliceTy:
return "[]" + bindTypeGo(*kind.Elem, structs)
default:
return bindBasicTypeGo(kind)
}
}
// bindBasicTypeJava converts basic solidity types(except array, slice and tuple) to Java one.
func bindBasicTypeJava(kind abi.Type) string {
switch kind.T {
case abi.AddressTy:
return "Address"
case abi.IntTy, abi.UintTy:
// 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(kind.String())
if len(parts) != 3 {
return kind.String()
}
// All unsigned integers should be translated to BigInt since gomobile doesn't
// support them.
if parts[1] == "u" {
return "BigInt"
}
namedSize := map[string]string{
"8": "byte",
"16": "short",
"32": "int",
"64": "long",
}[parts[2]]
// default to BigInt
if namedSize == "" {
namedSize = "BigInt"
}
return namedSize
case abi.FixedBytesTy, abi.BytesTy:
return "byte[]"
case abi.BoolTy:
return "boolean"
case abi.StringTy:
return "String"
case abi.FunctionTy:
return "byte[24]"
default:
return kind.String()
}
}
// pluralizeJavaType explicitly converts multidimensional types to predefined
// type in go side.
func pluralizeJavaType(typ string) string {
switch typ {
case "boolean":
return "Bools"
case "String":
return "Strings"
case "Address":
return "Addresses"
case "byte[]":
return "Binaries"
case "BigInt":
return "BigInts"
}
return typ + "[]"
}
// 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, structs map[string]*tmplStruct) string {
switch kind.T {
case abi.TupleTy:
return structs[kind.String()].Name
case abi.ArrayTy, abi.SliceTy:
return pluralizeJavaType(bindTypeJava(*kind.Elem, structs))
default:
return bindBasicTypeJava(kind)
}
}
// 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, structs map[string]*tmplStruct) string{
LangGo: bindTopicTypeGo,
LangJava: bindTopicTypeJava,
}
// bindTopicTypeGo 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, structs map[string]*tmplStruct) string {
bound := bindTypeGo(kind, structs)
if bound == "string" || bound == "[]byte" {
bound = "common.Hash"
}
return bound
}
// bindTopicTypeJava 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, structs map[string]*tmplStruct) string {
bound := bindTypeJava(kind, structs)
if bound == "String" || bound == "byte[]" {
bound = "Hash"
}
return bound
}
// bindStructType is a set of type binders that convert Solidity tuple types to some supported
// programming language struct definition.
var bindStructType = map[Lang]func(kind abi.Type, structs map[string]*tmplStruct) string{
LangGo: bindStructTypeGo,
LangJava: bindStructTypeJava,
}
// bindStructTypeGo converts a Solidity tuple type to a Go one and records the mapping
// in the given map.
// Notably, this function will resolve and record nested struct recursively.
func bindStructTypeGo(kind abi.Type, structs map[string]*tmplStruct) string {
switch kind.T {
case abi.TupleTy:
if s, exist := structs[kind.String()]; exist {
return s.Name
}
var fields []*tmplField
for i, elem := range kind.TupleElems {
field := bindStructTypeGo(*elem, structs)
fields = append(fields, &tmplField{Type: field, Name: capitalise(kind.TupleRawNames[i]), SolKind: *elem})
}
name := fmt.Sprintf("Struct%d", len(structs))
structs[kind.String()] = &tmplStruct{
Name: name,
Fields: fields,
}
return name
case abi.ArrayTy:
return fmt.Sprintf("[%d]", kind.Size) + bindStructTypeGo(*kind.Elem, structs)
case abi.SliceTy:
return "[]" + bindStructTypeGo(*kind.Elem, structs)
default:
return bindBasicTypeGo(kind)
}
}
// bindStructTypeJava converts a Solidity tuple type to a Java one and records the mapping
// in the given map.
// Notably, this function will resolve and record nested struct recursively.
func bindStructTypeJava(kind abi.Type, structs map[string]*tmplStruct) string {
switch kind.T {
case abi.TupleTy:
if s, exist := structs[kind.String()]; exist {
return s.Name
}
var fields []*tmplField
for i, elem := range kind.TupleElems {
field := bindStructTypeJava(*elem, structs)
fields = append(fields, &tmplField{Type: field, Name: decapitalise(kind.TupleRawNames[i]), SolKind: *elem})
}
name := fmt.Sprintf("Class%d", len(structs))
structs[kind.String()] = &tmplStruct{
Name: name,
Fields: fields,
}
return name
case abi.ArrayTy, abi.SliceTy:
return pluralizeJavaType(bindStructTypeJava(*kind.Elem, structs))
default:
return bindBasicTypeJava(kind)
}
}
// 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 "boolean":
return "Bool"
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: abi.ToCamelCase,
LangJava: decapitalise,
}
// capitalise makes a camel-case string which starts with an upper case character.
func capitalise(input string) string {
return abi.ToCamelCase(input)
}
// decapitalise makes a camel-case string which starts with a lower case character.
func decapitalise(input string) string {
if len(input) == 0 {
return input
}
goForm := abi.ToCamelCase(input)
return strings.ToLower(goForm[:1]) + goForm[1:]
}
// 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
}
// resolveArgName converts a raw argument representation into a user friendly format.
func resolveArgName(arg abi.Argument, structs map[string]*tmplStruct) string {
var (
prefix string
embedded string
typ = &arg.Type
)
loop:
for {
switch typ.T {
case abi.SliceTy:
prefix += "[]"
case abi.ArrayTy:
prefix += fmt.Sprintf("[%d]", typ.Size)
default:
embedded = typ.String()
break loop
}
typ = typ.Elem
}
if s, exist := structs[embedded]; exist {
return prefix + s.Name
} else {
return arg.Type.String()
}
}
// formatMethod transforms raw method representation into a user friendly one.
func formatMethod(method abi.Method, structs map[string]*tmplStruct) string {
inputs := make([]string, len(method.Inputs))
for i, input := range method.Inputs {
inputs[i] = fmt.Sprintf("%v %v", resolveArgName(input, structs), input.Name)
}
outputs := make([]string, len(method.Outputs))
for i, output := range method.Outputs {
outputs[i] = resolveArgName(output, structs)
if len(output.Name) > 0 {
outputs[i] += fmt.Sprintf(" %v", output.Name)
}
}
constant := ""
if method.Const {
constant = "constant "
}
return fmt.Sprintf("function %v(%v) %sreturns(%v)", method.Name, strings.Join(inputs, ", "), constant, strings.Join(outputs, ", "))
}
// formatEvent transforms raw event representation into a user friendly one.
func formatEvent(event abi.Event, structs map[string]*tmplStruct) string {
inputs := make([]string, len(event.Inputs))
for i, input := range event.Inputs {
if input.Indexed {
inputs[i] = fmt.Sprintf("%v indexed %v", resolveArgName(input, structs), input.Name)
} else {
inputs[i] = fmt.Sprintf("%v %v", resolveArgName(input, structs), input.Name)
}
}
return fmt.Sprintf("event %v(%v)", event.Name, strings.Join(inputs, ", "))
}