Merge pull request #2357 from karalabe/abi-binding-generator

accounts/abi/bind: Go ABI binding generator

1 files changed, 173 insertions, 0 deletions

diff --git a/accounts/abi/bind/bind.go b/accounts/abi/bind/bind.go
new file mode 100644
index 000000000..8b587f1aa
--- /dev/null
+++ b/accounts/abi/bind/bind.go
@@ -0,0 +1,173 @@
+// 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
+}