forked from cerc-io/plugeth
318 lines
13 KiB
Go
318 lines
13 KiB
Go
// Copyright 2016 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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// Package bind generates Ethereum contract Go bindings.
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package bind
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import (
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"bytes"
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"fmt"
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"sort"
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"strings"
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"github.com/ethereum/go-ethereum/accounts/abi"
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"golang.org/x/tools/imports"
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)
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// Bind generates a Go wrapper around a contract ABI. This wrapper isn't meant
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// to be used as is in client code, but rather as an intermediate struct which
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// enforces compile time type safety and naming convention opposed to having to
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// manually maintain hard coded strings that break on runtime.
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func Bind(jsonABI string, pkg string, kind string) (string, error) {
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// Parse the actual ABI to generate the binding for
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abi, err := abi.JSON(strings.NewReader(jsonABI))
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if err != nil {
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return "", err
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}
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// Generate the contract type, fields and methods
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code := new(bytes.Buffer)
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kind = strings.ToUpper(kind[:1]) + kind[1:]
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fmt.Fprintf(code, "%s\n", bindContract(kind, jsonABI))
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methods := make([]string, 0, len(abi.Methods))
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for name, _ := range abi.Methods {
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methods = append(methods, name)
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}
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sort.Strings(methods)
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for _, method := range methods {
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fmt.Fprintf(code, "%s\n", bindMethod(kind, abi.Methods[method]))
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}
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// Format the code with goimports and return
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buffer := new(bytes.Buffer)
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fmt.Fprintf(buffer, "package %s\n\n", pkg)
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fmt.Fprintf(buffer, "%s\n\n", string(code.Bytes()))
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blob, err := imports.Process("", buffer.Bytes(), nil)
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if err != nil {
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return "", err
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}
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return string(blob), nil
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}
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// bindContract generates the basic wrapper code for interacting with an Ethereum
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// contract via the abi package. All contract methods will call into the generic
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// ones generated here.
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func bindContract(kind string, abi string) string {
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code := ""
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// Generate the hard coded ABI used for Ethereum interaction
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code += fmt.Sprintf("// Ethereum ABI used to generate the binding from.\nconst %sABI = `%s`\n\n", kind, strings.TrimSpace(abi))
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// Generate the Go struct with all the maintenance fields
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code += fmt.Sprintf("// %s is an auto generated Go binding around an Ethereum contract.\n", kind)
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code += fmt.Sprintf("type %s struct {\n", kind)
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code += fmt.Sprintf(" %sCaller // Read-only binding to the contract\n", kind)
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code += fmt.Sprintf(" %sTransactor // Write-only binding to the contract\n", kind)
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code += fmt.Sprintf("}\n\n")
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code += fmt.Sprintf("// %sCaller is an auto generated read-only Go binding around an Ethereum contract.\n", kind)
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code += fmt.Sprintf("type %sCaller struct {\n", kind)
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code += fmt.Sprintf(" common *common%s // Contract binding common to callers and transactors\n", kind)
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code += fmt.Sprintf("}\n\n")
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code += fmt.Sprintf("// %sTransactor is an auto generated write-only Go binding around an Ethereum contract.\n", kind)
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code += fmt.Sprintf("type %sTransactor struct {\n", kind)
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code += fmt.Sprintf(" common *common%s // Contract binding common to callers and transactors\n", kind)
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code += fmt.Sprintf("}\n\n")
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code += fmt.Sprintf("// common%s is an auto generated Go binding around an Ethereum contract.\n", kind)
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code += fmt.Sprintf("type common%s struct {\n", kind)
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code += fmt.Sprintf(" contract *bind.BoundContract // Generic contract wrapper for the low level calls\n")
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code += fmt.Sprintf("}\n\n")
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// Generate the constructor to create a bound contract
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code += fmt.Sprintf("// New%s creates a new instance of %s, bound to a specific deployed contract.\n", kind, kind)
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code += fmt.Sprintf("func New%s(address common.Address, backend bind.ContractBackend) (*%s, error) {\n", kind, kind)
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code += fmt.Sprintf(" common, err := newCommon%s(address, backend.(bind.ContractCaller), backend.(bind.ContractTransactor))\n", kind)
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code += fmt.Sprintf(" if err != nil {\n")
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code += fmt.Sprintf(" return nil, err\n")
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code += fmt.Sprintf(" }\n")
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code += fmt.Sprintf(" return &%s{%sCaller: %sCaller{common: common}, %sTransactor: %sTransactor{common: common}}, nil\n", kind, kind, kind, kind, kind)
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code += fmt.Sprintf("}\n\n")
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code += fmt.Sprintf("// New%sCaller creates a new read-only instance of %s, bound to a specific deployed contract.\n", kind, kind)
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code += fmt.Sprintf("func New%sCaller(address common.Address, caller bind.ContractCaller) (*%sCaller, error) {\n", kind, kind)
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code += fmt.Sprintf(" common, err := newCommon%s(address, caller, nil)\n", kind)
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code += fmt.Sprintf(" if err != nil {\n")
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code += fmt.Sprintf(" return nil, err\n")
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code += fmt.Sprintf(" }\n")
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code += fmt.Sprintf(" return &%sCaller{common: common}, nil\n", kind)
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code += fmt.Sprintf("}\n\n")
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code += fmt.Sprintf("// New%sTransactor creates a new write-only instance of %s, bound to a specific deployed contract.\n", kind, kind)
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code += fmt.Sprintf("func New%sTransactor(address common.Address, transactor bind.ContractTransactor) (*%sTransactor, error) {\n", kind, kind)
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code += fmt.Sprintf(" common, err := newCommon%s(address, nil, transactor)\n", kind)
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code += fmt.Sprintf(" if err != nil {\n")
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code += fmt.Sprintf(" return nil, err\n")
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code += fmt.Sprintf(" }\n")
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code += fmt.Sprintf(" return &%sTransactor{common: common}, nil\n", kind)
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code += fmt.Sprintf("}\n\n")
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code += fmt.Sprintf("// newCommon%s creates an internal instance of %s, bound to a specific deployed contract.\n", kind, kind)
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code += fmt.Sprintf("func newCommon%s(address common.Address, caller bind.ContractCaller, transactor bind.ContractTransactor) (*common%s, error) {\n", kind, kind)
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code += fmt.Sprintf(" parsed, err := abi.JSON(strings.NewReader(%sABI))\n", kind)
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code += fmt.Sprintf(" if err != nil {\n")
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code += fmt.Sprintf(" return nil, err\n")
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code += fmt.Sprintf(" }\n")
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code += fmt.Sprintf(" return &common%s{\n", kind)
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code += fmt.Sprintf(" contract: bind.NewBoundContract(address, parsed, caller, transactor),\n")
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code += fmt.Sprintf(" }, nil\n")
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code += fmt.Sprintf("}")
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return code
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}
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// bindMethod
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func bindMethod(kind string, method abi.Method) string {
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var (
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name = strings.ToUpper(method.Name[:1]) + method.Name[1:]
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prologue = new(bytes.Buffer)
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)
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// Generate the argument and return list for the function
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args := make([]string, 0, len(method.Inputs))
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for i, arg := range method.Inputs {
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param := arg.Name
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if param == "" {
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param = fmt.Sprintf("arg%d", i)
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}
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args = append(args, fmt.Sprintf("%s %s", param, bindType(arg.Type)))
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}
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returns, _ := bindReturn(prologue, name, method.Outputs)
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// Generate the docs to help with coding against the binding
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callTypeDoc := "free data retrieval call"
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if !method.Const {
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callTypeDoc = "paid mutator transaction"
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}
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docs := fmt.Sprintf("// %s is a %s binding the contract method 0x%x.\n", name, callTypeDoc, method.Id())
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docs += fmt.Sprintf("// \n")
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docs += fmt.Sprintf("// Solidity: %s", strings.TrimPrefix(method.String(), "function "))
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// Generate the method itself for both the read/write version and the combo too
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code := fmt.Sprintf("%s\n", prologue)
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if method.Const {
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code += fmt.Sprintf("%s\nfunc (_%s *%sCaller) %s(%s) (%s) {\n%s\n}\n", docs, kind, kind, name, strings.Join(args, ","), strings.Join(returns, ","), bindCallBody(kind, method.Name, args, returns))
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} else {
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args = append([]string{"auth *bind.AuthOpts"}, args...)
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code += fmt.Sprintf("%s\nfunc (_%s *%sTransactor) %s(%s) (*types.Transaction, error) {\n%s\n}\n", docs, kind, kind, name, strings.Join(args, ","), bindTransactionBody(kind, method.Name, args))
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}
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return code
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}
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// bindType converts a Solidity type to a Go one. Since there is no clear mapping
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// from all Solidity types to Go ones (e.g. uint17), those that cannot be exactly
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// mapped will use an upscaled type (e.g. *big.Int).
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func bindType(kind abi.Type) string {
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stringKind := kind.String()
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switch {
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case stringKind == "address":
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return "common.Address"
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case stringKind == "hash":
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return "common.Hash"
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case strings.HasPrefix(stringKind, "bytes"):
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if stringKind == "bytes" {
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return "[]byte"
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}
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return fmt.Sprintf("[%s]byte", stringKind[5:])
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case strings.HasPrefix(stringKind, "int"):
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switch stringKind[:3] {
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case "8", "16", "32", "64":
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return stringKind
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}
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return "*big.Int"
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case strings.HasPrefix(stringKind, "uint"):
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switch stringKind[:4] {
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case "8", "16", "32", "64":
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return stringKind
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}
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return "*big.Int"
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default:
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return stringKind
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}
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}
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// bindReturn creates the list of return parameters for a method invocation. If
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// all the fields of the return type are named, and there is more than one value
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// being returned, the returns are wrapped in a result struct.
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func bindReturn(prologue *bytes.Buffer, method string, outputs []abi.Argument) ([]string, string) {
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// Generate the anonymous return list for when a struct is not needed/possible
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var (
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returns = make([]string, 0, len(outputs)+1)
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anonymous = false
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)
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for _, ret := range outputs {
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returns = append(returns, bindType(ret.Type))
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if ret.Name == "" {
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anonymous = true
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}
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}
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if anonymous || len(returns) < 2 {
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returns = append(returns, "error")
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return returns, ""
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}
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// If the returns are named and numerous, wrap in a result struct
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wrapper, impl := bindReturnStruct(method, outputs)
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prologue.WriteString(impl + "\n")
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return []string{"*" + wrapper, "error"}, wrapper
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}
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// bindReturnStruct creates a Go structure with the specified fields to be used
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// as the return type from a method call.
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func bindReturnStruct(method string, returns []abi.Argument) (string, string) {
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fields := make([]string, 0, len(returns))
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for _, ret := range returns {
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fields = append(fields, fmt.Sprintf("%s %s", strings.ToUpper(ret.Name[:1])+ret.Name[1:], bindType(ret.Type)))
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}
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kind := fmt.Sprintf("%sResult", method)
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docs := fmt.Sprintf("// %s is the result of the %s invocation.", kind, method)
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return kind, fmt.Sprintf("%s\ntype %s struct {\n%s\n}", docs, kind, strings.Join(fields, "\n"))
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}
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// bindCallBody creates the Go code to declare a batch of return values, invoke
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// an Ethereum method call with the requested parameters, parse the binary output
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// into the return values and return them.
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func bindCallBody(kind string, method string, params []string, returns []string) string {
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body := ""
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// Allocate memory for each of the return values
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rets := make([]string, 0, len(returns)-1)
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if len(returns) > 1 {
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body += "var ("
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for i, kind := range returns[:len(returns)-1] { // Omit the final error
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name := fmt.Sprintf("ret%d", i)
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rets = append(rets, name)
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body += fmt.Sprintf("%s = new(%s)\n", name, strings.TrimPrefix(kind, "*"))
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}
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body += ")\n"
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}
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// Assemble a single collector variable for the result ABI initialization
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result := strings.Join(rets, ",")
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if len(returns) > 2 {
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result = "[]interface{}{" + result + "}"
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}
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// Extract the parameter list into a flat variable name list
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inputs := make([]string, len(params))
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for i, param := range params {
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inputs[i] = strings.Split(param, " ")[0]
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}
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input := ""
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if len(inputs) > 0 {
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input = "," + strings.Join(inputs, ",")
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}
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// Request executing the contract call and return the results with the errors
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body += fmt.Sprintf("err := _%s.common.contract.Call(%s, \"%s\" %s)\n", kind, result, method, input)
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outs := make([]string, 0, len(returns))
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for i, ret := range returns[:len(returns)-1] { // Handle th final error separately
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if strings.HasPrefix(ret, "*") {
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outs = append(outs, rets[i])
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} else {
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outs = append(outs, "*"+rets[i])
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}
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}
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outs = append(outs, "err")
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body += fmt.Sprintf("return %s", strings.Join(outs, ","))
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return body
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}
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// bindTransactionBody creates the Go code to invoke an Ethereum transaction call
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// with the requested parameters, and return the assembled transaction object.
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func bindTransactionBody(kind string, method string, params []string) string {
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// Extract the parameter list into a flat variable name list
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inputs := make([]string, len(params)-1) // Omit the auth options
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for i, param := range params[1:] {
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inputs[i] = strings.Split(param, " ")[0]
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}
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input := ""
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if len(inputs) > 0 {
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input = "," + strings.Join(inputs, ",")
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}
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// Request executing the contract call and return the results with the errors
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return fmt.Sprintf("return _%s.common.contract.Transact(auth, \"%s\" %s)", kind, method, input)
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}
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