1 files changed, 317 insertions, 0 deletions
diff --git a/accounts/abi/bind/bind.go b/accounts/abi/bind/bind.go
new file mode 100644
index 000000000..bef75a158
--- /dev/null
+++ b/accounts/abi/bind/bind.go
@@ -0,0 +1,317 @@
+// 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.
+package bind
+
+import (
+	"bytes"
+	"fmt"
+	"sort"
+	"strings"
+
+	"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(jsonABI string, pkg string, kind string) (string, error) {
+	// Parse the actual ABI to generate the binding for
+	abi, err := abi.JSON(strings.NewReader(jsonABI))
+	if err != nil {
+		return "", err
+	}
+	// Generate the contract type, fields and methods
+	code := new(bytes.Buffer)
+	kind = strings.ToUpper(kind[:1]) + kind[1:]
+	fmt.Fprintf(code, "%s\n", bindContract(kind, jsonABI))
+
+	methods := make([]string, 0, len(abi.Methods))
+	for name, _ := range abi.Methods {
+		methods = append(methods, name)
+	}
+	sort.Strings(methods)
+
+	for _, method := range methods {
+		fmt.Fprintf(code, "%s\n", bindMethod(kind, abi.Methods[method]))
+	}
+	// Format the code with goimports and return
+	buffer := new(bytes.Buffer)
+
+	fmt.Fprintf(buffer, "package %s\n\n", pkg)
+	fmt.Fprintf(buffer, "%s\n\n", string(code.Bytes()))
+
+	blob, err := imports.Process("", buffer.Bytes(), nil)
+	if err != nil {
+		return "", err
+	}
+	return string(blob), nil
+}
+
+// bindContract generates the basic wrapper code for interacting with an Ethereum
+// contract via the abi package. All contract methods will call into the generic
+// ones generated here.
+func bindContract(kind string, abi string) string {
+	code := ""
+
+	// Generate the hard coded ABI used for Ethereum interaction
+	code += fmt.Sprintf("// Ethereum ABI used to generate the binding from.\nconst %sABI = `%s`\n\n", kind, strings.TrimSpace(abi))
+
+	// Generate the Go struct with all the maintenance fields
+	code += fmt.Sprintf("// %s is an auto generated Go binding around an Ethereum contract.\n", kind)
+	code += fmt.Sprintf("type %s struct {\n", kind)
+	code += fmt.Sprintf("  %sCaller     // Read-only binding to the contract\n", kind)
+	code += fmt.Sprintf("  %sTransactor // Write-only binding to the contract\n", kind)
+	code += fmt.Sprintf("}\n\n")
+
+	code += fmt.Sprintf("// %sCaller is an auto generated read-only Go binding around an Ethereum contract.\n", kind)
+	code += fmt.Sprintf("type %sCaller struct {\n", kind)
+	code += fmt.Sprintf("  common *common%s // Contract binding common to callers and transactors\n", kind)
+	code += fmt.Sprintf("}\n\n")
+
+	code += fmt.Sprintf("// %sTransactor is an auto generated write-only Go binding around an Ethereum contract.\n", kind)
+	code += fmt.Sprintf("type %sTransactor struct {\n", kind)
+	code += fmt.Sprintf("  common *common%s // Contract binding common to callers and transactors\n", kind)
+	code += fmt.Sprintf("}\n\n")
+
+	code += fmt.Sprintf("// common%s is an auto generated Go binding around an Ethereum contract.\n", kind)
+	code += fmt.Sprintf("type common%s struct {\n", kind)
+	code += fmt.Sprintf("  contract *bind.BoundContract // Generic contract wrapper for the low level calls\n")
+	code += fmt.Sprintf("}\n\n")
+
+	// Generate the constructor to create a bound contract
+	code += fmt.Sprintf("// New%s creates a new instance of %s, bound to a specific deployed contract.\n", kind, kind)
+	code += fmt.Sprintf("func New%s(address common.Address, backend bind.ContractBackend) (*%s, error) {\n", kind, kind)
+	code += fmt.Sprintf("  common, err := newCommon%s(address, backend.(bind.ContractCaller), backend.(bind.ContractTransactor))\n", kind)
+	code += fmt.Sprintf("  if err != nil {\n")
+	code += fmt.Sprintf("    return nil, err\n")
+	code += fmt.Sprintf("  }\n")
+	code += fmt.Sprintf("  return &%s{%sCaller: %sCaller{common: common}, %sTransactor: %sTransactor{common: common}}, nil\n", kind, kind, kind, kind, kind)
+	code += fmt.Sprintf("}\n\n")
+
+	code += fmt.Sprintf("// New%sCaller creates a new read-only instance of %s, bound to a specific deployed contract.\n", kind, kind)
+	code += fmt.Sprintf("func New%sCaller(address common.Address, caller bind.ContractCaller) (*%sCaller, error) {\n", kind, kind)
+	code += fmt.Sprintf("  common, err := newCommon%s(address, caller, nil)\n", kind)
+	code += fmt.Sprintf("  if err != nil {\n")
+	code += fmt.Sprintf("    return nil, err\n")
+	code += fmt.Sprintf("  }\n")
+	code += fmt.Sprintf("  return &%sCaller{common: common}, nil\n", kind)
+	code += fmt.Sprintf("}\n\n")
+
+	code += fmt.Sprintf("// New%sTransactor creates a new write-only instance of %s, bound to a specific deployed contract.\n", kind, kind)
+	code += fmt.Sprintf("func New%sTransactor(address common.Address, transactor bind.ContractTransactor) (*%sTransactor, error) {\n", kind, kind)
+	code += fmt.Sprintf("  common, err := newCommon%s(address, nil, transactor)\n", kind)
+	code += fmt.Sprintf("  if err != nil {\n")
+	code += fmt.Sprintf("    return nil, err\n")
+	code += fmt.Sprintf("  }\n")
+	code += fmt.Sprintf("  return &%sTransactor{common: common}, nil\n", kind)
+	code += fmt.Sprintf("}\n\n")
+
+	code += fmt.Sprintf("// newCommon%s creates an internal instance of %s, bound to a specific deployed contract.\n", kind, kind)
+	code += fmt.Sprintf("func newCommon%s(address common.Address, caller bind.ContractCaller, transactor bind.ContractTransactor) (*common%s, error) {\n", kind, kind)
+	code += fmt.Sprintf("  parsed, err := abi.JSON(strings.NewReader(%sABI))\n", kind)
+	code += fmt.Sprintf("  if err != nil {\n")
+	code += fmt.Sprintf("    return nil, err\n")
+	code += fmt.Sprintf("  }\n")
+	code += fmt.Sprintf("  return &common%s{\n", kind)
+	code += fmt.Sprintf("    contract: bind.NewBoundContract(address, parsed, caller, transactor),\n")
+	code += fmt.Sprintf("  }, nil\n")
+	code += fmt.Sprintf("}")
+
+	return code
+}
+
+// bindMethod
+func bindMethod(kind string, method abi.Method) string {
+	var (
+		name     = strings.ToUpper(method.Name[:1]) + method.Name[1:]
+		prologue = new(bytes.Buffer)
+	)
+	// Generate the argument and return list for the function
+	args := make([]string, 0, len(method.Inputs))
+	for i, arg := range method.Inputs {
+		param := arg.Name
+		if param == "" {
+			param = fmt.Sprintf("arg%d", i)
+		}
+		args = append(args, fmt.Sprintf("%s %s", param, bindType(arg.Type)))
+	}
+	returns, _ := bindReturn(prologue, name, method.Outputs)
+
+	// Generate the docs to help with coding against the binding
+	callTypeDoc := "free data retrieval call"
+	if !method.Const {
+		callTypeDoc = "paid mutator transaction"
+	}
+	docs := fmt.Sprintf("// %s is a %s binding the contract method 0x%x.\n", name, callTypeDoc, method.Id())
+	docs += fmt.Sprintf("// \n")
+	docs += fmt.Sprintf("// Solidity: %s", strings.TrimPrefix(method.String(), "function "))
+
+	// Generate the method itself for both the read/write version and the combo too
+	code := fmt.Sprintf("%s\n", prologue)
+	if method.Const {
+		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))
+	} else {
+		args = append([]string{"auth *bind.AuthOpts"}, args...)
+		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))
+	}
+	return code
+}
+
+// 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
+	}
+}
+
+// bindReturn creates the list of return parameters for a method invocation. If
+// all the fields of the return type are named, and there is more than one value
+// being returned, the returns are wrapped in a result struct.
+func bindReturn(prologue *bytes.Buffer, method string, outputs []abi.Argument) ([]string, string) {
+	// Generate the anonymous return list for when a struct is not needed/possible
+	var (
+		returns   = make([]string, 0, len(outputs)+1)
+		anonymous = false
+	)
+	for _, ret := range outputs {
+		returns = append(returns, bindType(ret.Type))
+		if ret.Name == "" {
+			anonymous = true
+		}
+	}
+	if anonymous || len(returns) < 2 {
+		returns = append(returns, "error")
+		return returns, ""
+	}
+	// If the returns are named and numerous, wrap in a result struct
+	wrapper, impl := bindReturnStruct(method, outputs)
+	prologue.WriteString(impl + "\n")
+	return []string{"*" + wrapper, "error"}, wrapper
+}
+
+// bindReturnStruct creates a Go structure with the specified fields to be used
+// as the return type from a method call.
+func bindReturnStruct(method string, returns []abi.Argument) (string, string) {
+	fields := make([]string, 0, len(returns))
+	for _, ret := range returns {
+		fields = append(fields, fmt.Sprintf("%s %s", strings.ToUpper(ret.Name[:1])+ret.Name[1:], bindType(ret.Type)))
+	}
+	kind := fmt.Sprintf("%sResult", method)
+	docs := fmt.Sprintf("// %s is the result of the %s invocation.", kind, method)
+
+	return kind, fmt.Sprintf("%s\ntype %s struct {\n%s\n}", docs, kind, strings.Join(fields, "\n"))
+}
+
+// bindCallBody creates the Go code to declare a batch of return values, invoke
+// an Ethereum method call with the requested parameters, parse the binary output
+// into the return values and return them.
+func bindCallBody(kind string, method string, params []string, returns []string) string {
+	body := ""
+
+	// Allocate memory for each of the return values
+	rets := make([]string, 0, len(returns)-1)
+	if len(returns) > 1 {
+		body += "var ("
+		for i, kind := range returns[:len(returns)-1] { // Omit the final error
+			name := fmt.Sprintf("ret%d", i)
+
+			rets = append(rets, name)
+			body += fmt.Sprintf("%s = new(%s)\n", name, strings.TrimPrefix(kind, "*"))
+		}
+		body += ")\n"
+	}
+	// Assemble a single collector variable for the result ABI initialization
+	result := strings.Join(rets, ",")
+	if len(returns) > 2 {
+		result = "[]interface{}{" + result + "}"
+	}
+	// Extract the parameter list into a flat variable name list
+	inputs := make([]string, len(params))
+	for i, param := range params {
+		inputs[i] = strings.Split(param, " ")[0]
+	}
+	input := ""
+	if len(inputs) > 0 {
+		input = "," + strings.Join(inputs, ",")
+	}
+	// Request executing the contract call and return the results with the errors
+	body += fmt.Sprintf("err := _%s.common.contract.Call(%s, \"%s\" %s)\n", kind, result, method, input)
+
+	outs := make([]string, 0, len(returns))
+	for i, ret := range returns[:len(returns)-1] { // Handle th final error separately
+		if strings.HasPrefix(ret, "*") {
+			outs = append(outs, rets[i])
+		} else {
+			outs = append(outs, "*"+rets[i])
+		}
+	}
+	outs = append(outs, "err")
+
+	body += fmt.Sprintf("return %s", strings.Join(outs, ","))
+
+	return body
+}
+
+// bindTransactionBody creates the Go code to invoke an Ethereum transaction call
+// with the requested parameters, and return the assembled transaction object.
+func bindTransactionBody(kind string, method string, params []string) string {
+	// Extract the parameter list into a flat variable name list
+	inputs := make([]string, len(params)-1) // Omit the auth options
+	for i, param := range params[1:] {
+		inputs[i] = strings.Split(param, " ")[0]
+	}
+	input := ""
+	if len(inputs) > 0 {
+		input = "," + strings.Join(inputs, ",")
+	}
+	// Request executing the contract call and return the results with the errors
+	return fmt.Sprintf("return _%s.common.contract.Transact(auth, \"%s\" %s)", kind, method, input)
+}