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cmd/cloner,util/codegen: refactor cloner internals to allow reuse

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Also run go generate again for Copyright updates.

Signed-off-by: Maisem Ali <maisem@tailscale.com>
This commit is contained in:
Maisem Ali
2022-05-01 16:15:14 -07:00
committed by Maisem Ali
parent 025867fd07
commit e409e59a54
14 changed files with 159 additions and 124 deletions
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101
cmd/cloner/cloner.go
View File

@@ -22,13 +22,11 @@ import (
"os"
"strings"
"golang.org/x/tools/go/packages"
"tailscale.com/util/codegen"
)
var (
flagTypes = flag.String("type", "", "comma-separated list of types; required")
flagOutput = flag.String("output", "", "output file; required")
flagBuildTags = flag.String("tags", "", "compiler build tags to apply")
flagCloneFunc = flag.Bool("clonefunc", false, "add a top-level Clone func")
)
@@ -43,30 +41,18 @@ func main() {
}
typeNames := strings.Split(*flagTypes, ",")
cfg := &packages.Config{
Mode: packages.NeedTypes | packages.NeedTypesInfo | packages.NeedSyntax | packages.NeedName,
Tests: false,
}
if *flagBuildTags != "" {
cfg.BuildFlags = []string{"-tags=" + *flagBuildTags}
}
pkgs, err := packages.Load(cfg, ".")
pkg, namedTypes, err := codegen.LoadTypes(*flagBuildTags, ".")
if err != nil {
log.Fatal(err)
}
if len(pkgs) != 1 {
log.Fatalf("wrong number of packages: %d", len(pkgs))
}
pkg := pkgs[0]
it := codegen.NewImportTracker(pkg.Types)
buf := new(bytes.Buffer)
imports := make(map[string]struct{})
namedTypes := codegen.NamedTypes(pkg)
for _, typeName := range typeNames {
typ, ok := namedTypes[typeName]
if !ok {
log.Fatalf("could not find type %s", typeName)
}
gen(buf, imports, typ, pkg.Types)
gen(buf, it, typ)
}
w := func(format string, args ...any) {
@@ -93,62 +79,13 @@ func main() {
w(" return false")
w("}")
}
contents := new(bytes.Buffer)
var flagArgs []string
if *flagTypes != "" {
flagArgs = append(flagArgs, "-type="+*flagTypes)
}
if *flagOutput != "" {
flagArgs = append(flagArgs, "-output="+*flagOutput)
}
if *flagBuildTags != "" {
flagArgs = append(flagArgs, "-tags="+*flagBuildTags)
}
if *flagCloneFunc {
flagArgs = append(flagArgs, "-clonefunc")
}
fmt.Fprintf(contents, header, strings.Join(flagArgs, " "), pkg.Name)
fmt.Fprintf(contents, "import (\n")
for s := range imports {
fmt.Fprintf(contents, "\t%q\n", s)
}
fmt.Fprintf(contents, ")\n\n")
contents.Write(buf.Bytes())
output := *flagOutput
if output == "" {
flag.Usage()
os.Exit(2)
}
if err := codegen.WriteFormatted(contents.Bytes(), output); err != nil {
cloneOutput := pkg.Name + "_clone.go"
if err := codegen.WritePackageFile("tailscale.com/cmd/cloner", pkg, cloneOutput, it, buf); err != nil {
log.Fatal(err)
}
}
const header = `// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Code generated by tailscale.com/cmd/cloner; DO NOT EDIT.
//` + `go:generate` + ` go run tailscale.com/cmd/cloner %s
package %s
`
func gen(buf *bytes.Buffer, imports map[string]struct{}, typ *types.Named, thisPkg *types.Package) {
pkgQual := func(pkg *types.Package) string {
if thisPkg == pkg {
return ""
}
imports[pkg.Path()] = struct{}{}
return pkg.Name()
}
importedName := func(t types.Type) string {
return types.TypeString(t, pkgQual)
}
func gen(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named) {
t, ok := typ.Underlying().(*types.Struct)
if !ok {
return
@@ -169,11 +106,11 @@ func gen(buf *bytes.Buffer, imports map[string]struct{}, typ *types.Named, thisP
for i := 0; i < t.NumFields(); i++ {
fname := t.Field(i).Name()
ft := t.Field(i).Type()
if !codegen.ContainsPointers(ft) {
if !codegen.ContainsPointers(ft) || codegen.HasNoClone(t.Tag(i)) {
continue
}
if named, _ := ft.(*types.Named); named != nil {
if isViewType(ft) {
if codegen.IsViewType(ft) {
writef("dst.%s = src.%s", fname, fname)
continue
}
@@ -185,7 +122,7 @@ func gen(buf *bytes.Buffer, imports map[string]struct{}, typ *types.Named, thisP
switch ft := ft.Underlying().(type) {
case *types.Slice:
if codegen.ContainsPointers(ft.Elem()) {
n := importedName(ft.Elem())
n := it.QualifiedName(ft.Elem())
writef("dst.%s = make([]%s, len(src.%s))", fname, n, fname)
writef("for i := range dst.%s {", fname)
if _, isPtr := ft.Elem().(*types.Pointer); isPtr {
@@ -202,7 +139,7 @@ func gen(buf *bytes.Buffer, imports map[string]struct{}, typ *types.Named, thisP
writef("dst.%s = src.%s.Clone()", fname, fname)
continue
}
n := importedName(ft.Elem())
n := it.QualifiedName(ft.Elem())
writef("if dst.%s != nil {", fname)
writef("\tdst.%s = new(%s)", fname, n)
writef("\t*dst.%s = *src.%s", fname, fname)
@@ -212,9 +149,9 @@ func gen(buf *bytes.Buffer, imports map[string]struct{}, typ *types.Named, thisP
writef("}")
case *types.Map:
writef("if dst.%s != nil {", fname)
writef("\tdst.%s = map[%s]%s{}", fname, importedName(ft.Key()), importedName(ft.Elem()))
writef("\tdst.%s = map[%s]%s{}", fname, it.QualifiedName(ft.Key()), it.QualifiedName(ft.Elem()))
if sliceType, isSlice := ft.Elem().(*types.Slice); isSlice {
n := importedName(sliceType.Elem())
n := it.QualifiedName(sliceType.Elem())
writef("\tfor k := range src.%s {", fname)
// use zero-length slice instead of nil to ensure
// the key is always copied.
@@ -237,20 +174,10 @@ func gen(buf *bytes.Buffer, imports map[string]struct{}, typ *types.Named, thisP
writef("return dst")
fmt.Fprintf(buf, "}\n\n")
buf.Write(codegen.AssertStructUnchanged(t, thisPkg, name, "Clone", imports))
}
func isViewType(typ types.Type) bool {
t, ok := typ.Underlying().(*types.Struct)
if !ok {
return false
}
if t.NumFields() != 1 {
return false
}
return t.Field(0).Name() == "ж"
buf.Write(codegen.AssertStructUnchanged(t, name, "Clone", it))
}
// hasBasicUnderlying reports true when typ.Underlying() is a slice or a map.
func hasBasicUnderlying(typ types.Type) bool {
switch typ.Underlying().(type) {
case *types.Slice, *types.Map: