go-ethereum/rlp/rlpgen/main.go

148 lines
3.8 KiB
Go

// Copyright 2022 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 main
import (
"bytes"
"errors"
"flag"
"fmt"
"go/types"
"os"
"golang.org/x/tools/go/packages"
)
const pathOfPackageRLP = "github.com/ethereum/go-ethereum/rlp"
func main() {
var (
pkgdir = flag.String("dir", ".", "input package")
output = flag.String("out", "-", "output file (default is stdout)")
genEncoder = flag.Bool("encoder", true, "generate EncodeRLP?")
genDecoder = flag.Bool("decoder", false, "generate DecodeRLP?")
typename = flag.String("type", "", "type to generate methods for")
)
flag.Parse()
cfg := Config{
Dir: *pkgdir,
Type: *typename,
GenerateEncoder: *genEncoder,
GenerateDecoder: *genDecoder,
}
code, err := cfg.process()
if err != nil {
fatal(err)
}
if *output == "-" {
os.Stdout.Write(code)
} else if err := os.WriteFile(*output, code, 0600); err != nil {
fatal(err)
}
}
func fatal(args ...interface{}) {
fmt.Fprintln(os.Stderr, args...)
os.Exit(1)
}
type Config struct {
Dir string // input package directory
Type string
GenerateEncoder bool
GenerateDecoder bool
}
// process generates the Go code.
func (cfg *Config) process() (code []byte, err error) {
// Load packages.
pcfg := &packages.Config{
Mode: packages.NeedName | packages.NeedTypes | packages.NeedImports | packages.NeedDeps,
Dir: cfg.Dir,
BuildFlags: []string{"-tags", "norlpgen"},
}
ps, err := packages.Load(pcfg, pathOfPackageRLP, ".")
if err != nil {
return nil, err
}
if len(ps) == 0 {
return nil, fmt.Errorf("no Go package found in %s", cfg.Dir)
}
packages.PrintErrors(ps)
// Find the packages that were loaded.
var (
pkg *types.Package
packageRLP *types.Package
)
for _, p := range ps {
if len(p.Errors) > 0 {
return nil, fmt.Errorf("package %s has errors", p.PkgPath)
}
if p.PkgPath == pathOfPackageRLP {
packageRLP = p.Types
} else {
pkg = p.Types
}
}
bctx := newBuildContext(packageRLP)
// Find the type and generate.
typ, err := lookupStructType(pkg.Scope(), cfg.Type)
if err != nil {
return nil, fmt.Errorf("can't find %s in %s: %v", typ, pkg, err)
}
code, err = bctx.generate(typ, cfg.GenerateEncoder, cfg.GenerateDecoder)
if err != nil {
return nil, err
}
// Add build comments.
// This is done here to avoid processing these lines with gofmt.
var header bytes.Buffer
fmt.Fprint(&header, "// Code generated by rlpgen. DO NOT EDIT.\n\n")
fmt.Fprint(&header, "//go:build !norlpgen\n")
fmt.Fprint(&header, "// +build !norlpgen\n\n")
return append(header.Bytes(), code...), nil
}
func lookupStructType(scope *types.Scope, name string) (*types.Named, error) {
typ, err := lookupType(scope, name)
if err != nil {
return nil, err
}
_, ok := typ.Underlying().(*types.Struct)
if !ok {
return nil, errors.New("not a struct type")
}
return typ, nil
}
func lookupType(scope *types.Scope, name string) (*types.Named, error) {
obj := scope.Lookup(name)
if obj == nil {
return nil, errors.New("no such identifier")
}
typ, ok := obj.(*types.TypeName)
if !ok {
return nil, errors.New("not a type")
}
return typ.Type().(*types.Named), nil
}