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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/ethereum/go-ethereum/wiki/Native-DApps:-Go-bindings-to-Ethereum-contracts
package bind
import (
"bytes"
"fmt"
"strings"
"text/template"
"unicode"
"github.com/ethereum/go-ethereum/accounts/abi"
"golang.org/x/tools/imports"
)
// 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) (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 = capitalise(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 methos 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: strippedABI,
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,
}
tmpl := template.Must(template.New("").Funcs(funcs).Parse(tmplSource))
if err := tmpl.Execute(buffer, data); err != nil {
return "", err
}
// Pass the code through goimports to clean it up and double check
code, err := imports.Process("", buffer.Bytes(), nil)
if err != nil {
return "", fmt.Errorf("%v\n%s", err, buffer)
}
return string(code), nil
}
// bindType 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 bindType(kind abi.Type) string {
stringKind := kind.String()
switch {
case stringKind == "address":
return "common.Address"
case stringKind == "hash":
return "common.Hash"
case strings.HasPrefix(stringKind, "bytes"):
if stringKind == "bytes" {
return "[]byte"
}
return fmt.Sprintf("[%s]byte", stringKind[5:])
case strings.HasPrefix(stringKind, "int"):
switch stringKind[:3] {
case "8", "16", "32", "64":
return stringKind
}
return "*big.Int"
case strings.HasPrefix(stringKind, "uint"):
switch stringKind[:4] {
case "8", "16", "32", "64":
return stringKind
}
return "*big.Int"
default:
return stringKind
}
}
// capitalise makes the first character of a string upper case.
func capitalise(input string) string {
return strings.ToUpper(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
}
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