feat: internalise command

Author: ARR4N

core/types/block.go

@@ -60,6 +60,7 @@ func (n *BlockNonce) UnmarshalText(input []byte) error {
 
 //go:generate go run github.com/fjl/gencodec -type Header -field-override headerMarshaling -out gen_header_json.go
 //go:generate go run ../../rlp/rlpgen -type Header -out gen_header_rlp.go
+//go:generate go run ../../libevm/cmd/internalise -file gen_header_rlp.go Header.EncodeRLP
 
 // Header represents a block header in the Ethereum blockchain.
 type Header struct {

libevm/cmd/internalise/main.go

@@ -0,0 +1,116 @@
+// Copyright 2024 the libevm authors.
+//
+// The libevm additions to go-ethereum are free software: you can redistribute
+// them and/or modify them 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 libevm additions are distributed in the hope that they 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/>.
+
+// The internalise command modifies Go files in place, making exported methods
+// internal.
+//
+// Usage:
+//
+//	internalise -file <filepath> <type>.<method> [<type>.<method> [...]]
+//
+// For example, with file foo.go containing declarations:
+//
+//	func (f *Foo) Bar() { ... }
+//
+//	func (Foo) Baz() { ... }
+//
+// running
+//
+//	internalise -file foo.go Foo.Bar Foo.Baz
+//
+// results in
+//
+//	func (f *Foo) bar() { ... }
+//
+//	func (Foo) baz() { ... }
+package main
+
+import (
+	"flag"
+	"fmt"
+	"go/ast"
+	"go/format"
+	"go/parser"
+	"go/token"
+	"os"
+	"strings"
+)
+
+func main() {
+	file := flag.String("file", "", "File to modify")
+	flag.Parse()
+
+	if err := run(*file, flag.Args()...); err != nil {
+		fmt.Fprint(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+
+func run(fileName string, args ...string) error {
+	methods := make(map[string]map[string]struct{})
+	for _, a := range args {
+		a = strings.TrimPrefix(strings.TrimSpace(a), "*")
+		parts := strings.Split(a, ".")
+		if len(parts) != 2 {
+			return fmt.Errorf("invalid method identifier %q", a)
+		}
+		typ, fn := parts[0], parts[1]
+		if _, ok := methods[typ]; !ok {
+			methods[typ] = make(map[string]struct{})
+		}
+		methods[typ][fn] = struct{}{}
+	}
+
+	fset := token.NewFileSet()
+	mode := parser.SkipObjectResolution | parser.ParseComments
+	parsed, err := parser.ParseFile(fset, fileName, nil, mode)
+	if err != nil {
+		return err
+	}
+
+	for _, d := range parsed.Decls {
+		fn, ok := d.(*ast.FuncDecl)
+		if !ok || fn.Recv.NumFields() != 1 {
+			continue
+		}
+
+		var typ string
+		switch t := fn.Recv.List[0].Type.(type) {
+		case *ast.Ident:
+			typ = t.Name
+		case *ast.StarExpr:
+			typ = t.X.(*ast.Ident).Name
+		}
+
+		name := &fn.Name.Name
+		if _, ok := methods[typ][*name]; !ok {
+			continue
+		}
+		if n := []rune(*name); n[0] >= 'A' && n[0] <= 'Z' {
+			n[0] += 'a' - 'A'
+			*name = string(n)
+		}
+	}
+
+	f, err := os.OpenFile(fileName, os.O_TRUNC|os.O_WRONLY, 0)
+	if err != nil {
+		return err
+	}
+	if err := format.Node(f, fset, parsed); err != nil {
+		return err
+	}
+	return f.Close()
+}