internal/cmd/qgo/qgo.go - cue - Git at Google

 // Copyright 2018 The CUE Authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 // qgo builds CUE builtin packages from Go packages.
 package main

 import (
 	"bytes"
 	"flag"
 	"fmt"
 	"go/ast"
 	"go/constant"
 	"go/format"
 	"go/printer"
 	"go/token"
 	"go/types"
 	"io"
 	"io/ioutil"
 	"log"
 	"os"
 	"path/filepath"
 	"regexp"
 	"strings"

 	"golang.org/x/tools/go/packages"
 )

 const help = `
 Commands:
 extract		Extract one-line signature of exported types of
 			the given package.

 			Functions that have have more than one return
 			argument or unknown types are skipped.
 `

 // Even though all of the code is generated, the documentation is copied as is.
 // So for proper measure, include both the CUE and Go licenses.
 const copyright = `// Copyright 2020 The CUE Authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 // Copyright 2018 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 `

 var genLine string

 var (
 	exclude  = flag.String("exclude", "", "comma-separated list of regexps of entries to exclude")
 	stripstr = flag.Bool("stripstr", false, "Remove String suffix from functions")
 )

 func init() {
 	log.SetFlags(log.Lshortfile)
 }

 func main() {
 	flag.Parse()

 	genLine = "//go:generate go run cuelang.org/go/internal/cmd/qgo " + strings.Join(os.Args[1:], " ")

 	args := flag.Args()
 	if len(args) == 0 {
 		fmt.Println(strings.TrimSpace(help))
 		return
 	}

 	command := args[0]
 	args = args[1:]

 	switch command {
 	case "extract":
 		extract(args)
 	}
 }

 var exclusions []*regexp.Regexp

 func initExclusions() {
 	for _, re := range strings.Split(*exclude, ",") {
 		if re != "" {
 			exclusions = append(exclusions, regexp.MustCompile(re))
 		}
 	}
 }

 func filter(name string) bool {
 	if !ast.IsExported(name) {
 		return true
 	}
 	for _, ex := range exclusions {
 		if ex.MatchString(name) {
 			return true
 		}
 	}
 	return false
 }

 func pkgName() string {
 	pkg, err := os.Getwd()
 	if err != nil {
 		log.Fatal(err)
 	}
 	return filepath.Base(pkg)
 }

 type extracter struct {
 	pkg *packages.Package
 }

 func extract(args []string) {
 	cfg := &packages.Config{
 		Mode: packages.LoadFiles |
 			packages.LoadAllSyntax |
 			packages.LoadTypes,
 	}
 	pkgs, err := packages.Load(cfg, args...)
 	if err != nil {
 		log.Fatal(err)
 	}

 	e := extracter{}

 	lastPkg := ""
 	var w *bytes.Buffer
 	initExclusions()

 	flushFile := func() {
 		if w != nil && w.Len() > 0 {
 			b, err := format.Source(w.Bytes())
 			if err != nil {
 				log.Fatal(err)
 			}
 			err = ioutil.WriteFile(lastPkg+".go", b, 0644)
 			if err != nil {
 				log.Fatal(err)
 			}
 		}
 		w = &bytes.Buffer{}
 	}

 	for _, p := range pkgs {
 		e.pkg = p
 		for _, f := range p.Syntax {
 			if lastPkg != p.Name {
 				flushFile()
 				lastPkg = p.Name
 				fmt.Fprintln(w, copyright)
 				fmt.Fprintln(w, genLine)
 				fmt.Fprintln(w)
 				fmt.Fprintf(w, "package %s\n", pkgName())
 				fmt.Fprintln(w)
 				fmt.Fprintf(w, "import %q", p.PkgPath)
 				fmt.Fprintln(w)
 			}

 			for _, d := range f.Decls {
 				switch x := d.(type) {
 				case *ast.FuncDecl:
 					e.reportFun(w, x)
 				case *ast.GenDecl:
 					e.reportDecl(w, x)
 				}
 			}
 		}
 	}
 	flushFile()
 }

 func (e *extracter) reportFun(w io.Writer, x *ast.FuncDecl) {
 	if filter(x.Name.Name) {
 		return
 	}
 	pkgName := e.pkg.Name
 	override := ""
 	params := []ast.Expr{}
 	if x.Type.Params != nil {
 		for _, f := range x.Type.Params.List {
 			tx := f.Type
 			if star, isStar := tx.(*ast.StarExpr); isStar {
 				if i, ok := star.X.(*ast.Ident); ok && ast.IsExported(i.Name) {
 					f.Type = &ast.SelectorExpr{X: ast.NewIdent(pkgName), Sel: i}
 					if isStar {
 						f.Type = &ast.StarExpr{X: f.Type}
 					}
 				}
 			}
 			for _, n := range f.Names {
 				params = append(params, n)
 				if n.Name == pkgName {
 					override = pkgName + x.Name.Name
 				}
 			}
 		}
 	}
 	var fn ast.Expr = &ast.SelectorExpr{
 		X:   ast.NewIdent(pkgName),
 		Sel: x.Name,
 	}
 	if override != "" {
 		fn = ast.NewIdent(override)
 	}
 	x.Body = &ast.BlockStmt{List: []ast.Stmt{
 		&ast.ReturnStmt{Results: []ast.Expr{&ast.CallExpr{
 			Fun:  fn,
 			Args: params,
 		}}},
 	}}
 	if name := x.Name.Name; *stripstr && strings.HasSuffix(name, "String") {
 		newName := name[:len(name)-len("String")]
 		x.Name = ast.NewIdent(newName)
 		if x.Doc != nil {
 			for _, c := range x.Doc.List {
 				c.Text = strings.Replace(c.Text, name, newName, -1)
 			}
 		}
 	}
 	types := []ast.Expr{}
 	if x.Recv == nil && x.Type != nil && x.Type.Results != nil && !strings.HasPrefix(x.Name.Name, "New") {
 		for _, f := range x.Type.Results.List {
 			if len(f.Names) == 0 {
 				types = append(types, f.Type)
 			} else {
 				for range f.Names {
 					types = append(types, f.Type)
 				}
 			}
 		}
 	}
 	if len(types) != 1 {
 		switch len(types) {
 		case 2:
 			if i, ok := types[1].(*ast.Ident); ok && i.Name == "error" {
 				break
 			}
 			fallthrough
 		default:
 			fmt.Printf("Skipping ")
 			x.Doc = nil
 			printer.Fprint(os.Stdout, e.pkg.Fset, x)
 			fmt.Println()
 			return
 		}
 	}
 	fmt.Fprintln(w)
 	printer.Fprint(w, e.pkg.Fset, x.Doc)
 	printer.Fprint(w, e.pkg.Fset, x)
 	fmt.Fprint(w, "\n")
 	if override != "" {
 		fmt.Fprintf(w, "var %s = %s.%s\n\n", override, pkgName, x.Name.Name)
 	}
 }

 func (e *extracter) reportDecl(w io.Writer, x *ast.GenDecl) {
 	if x.Tok != token.CONST {
 		return
 	}
 	k := 0
 	for _, s := range x.Specs {
 		if v, ok := s.(*ast.ValueSpec); ok && !filter(v.Names[0].Name) {
 			if v.Values == nil {
 				v.Values = make([]ast.Expr, len(v.Names))
 			}
 			for i, expr := range v.Names {
 				// This check can be removed if we set constants to floats.
 				if _, ok := v.Values[i].(*ast.BasicLit); ok {
 					continue
 				}
 				tv, _ := types.Eval(e.pkg.Fset, e.pkg.Types, v.Pos(), v.Names[0].Name)
 				tok := token.ILLEGAL
 				switch tv.Value.Kind() {
 				case constant.Bool:
 					v.Values[i] = ast.NewIdent(tv.Value.ExactString())
 					continue
 				case constant.String:
 					tok = token.STRING
 				case constant.Int:
 					tok = token.INT
 				case constant.Float:
 					tok = token.FLOAT
 				default:
 					fmt.Printf("Skipping %s\n", v.Names)
 					continue
 				}
 				v.Values[i] = &ast.BasicLit{
 					ValuePos: expr.Pos(),
 					Kind:     tok,
 					Value:    tv.Value.ExactString(),
 				}
 			}
 			v.Type = nil
 			x.Specs[k] = v
 			k++
 		}
 	}
 	x.Specs = x.Specs[:k]
 	if len(x.Specs) == 0 {
 		return
 	}
 	fmt.Fprintln(w)
 	printer.Fprint(w, e.pkg.Fset, x)
 	fmt.Fprintln(w)
 }
	// Copyright 2018 The CUE Authors
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	// qgo builds CUE builtin packages from Go packages.
	package main

	import (
	"bytes"
	"flag"
	"fmt"
	"go/ast"
	"go/constant"
	"go/format"
	"go/printer"
	"go/token"
	"go/types"
	"io"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"
	"regexp"
	"strings"

	"golang.org/x/tools/go/packages"
	)

	const help = `
	Commands:
	extract Extract one-line signature of exported types of
	the given package.

	Functions that have have more than one return
	argument or unknown types are skipped.
	`

	// Even though all of the code is generated, the documentation is copied as is.
	// So for proper measure, include both the CUE and Go licenses.
	const copyright = `// Copyright 2020 The CUE Authors
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	// Copyright 2018 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.
	`

	var genLine string

	var (
	exclude = flag.String("exclude", "", "comma-separated list of regexps of entries to exclude")
	stripstr = flag.Bool("stripstr", false, "Remove String suffix from functions")
	)

	func init() {
	log.SetFlags(log.Lshortfile)
	}

	func main() {
	flag.Parse()

	genLine = "//go:generate go run cuelang.org/go/internal/cmd/qgo " + strings.Join(os.Args[1:], " ")

	args := flag.Args()
	if len(args) == 0 {
	fmt.Println(strings.TrimSpace(help))
	return
	}

	command := args[0]
	args = args[1:]

	switch command {
	case "extract":
	extract(args)
	}
	}

	var exclusions []*regexp.Regexp

	func initExclusions() {
	for _, re := range strings.Split(*exclude, ",") {
	if re != "" {
	exclusions = append(exclusions, regexp.MustCompile(re))
	}
	}
	}

	func filter(name string) bool {
	if !ast.IsExported(name) {
	return true
	}
	for _, ex := range exclusions {
	if ex.MatchString(name) {
	return true
	}
	}
	return false
	}

	func pkgName() string {
	pkg, err := os.Getwd()
	if err != nil {
	log.Fatal(err)
	}
	return filepath.Base(pkg)
	}

	type extracter struct {
	pkg *packages.Package
	}

	func extract(args []string) {
	cfg := &packages.Config{
	Mode: packages.LoadFiles \|
	packages.LoadAllSyntax \|
	packages.LoadTypes,
	}
	pkgs, err := packages.Load(cfg, args...)
	if err != nil {
	log.Fatal(err)
	}

	e := extracter{}

	lastPkg := ""
	var w *bytes.Buffer
	initExclusions()

	flushFile := func() {
	if w != nil && w.Len() > 0 {
	b, err := format.Source(w.Bytes())
	if err != nil {
	log.Fatal(err)
	}
	err = ioutil.WriteFile(lastPkg+".go", b, 0644)
	if err != nil {
	log.Fatal(err)
	}
	}
	w = &bytes.Buffer{}
	}

	for _, p := range pkgs {
	e.pkg = p
	for _, f := range p.Syntax {
	if lastPkg != p.Name {
	flushFile()
	lastPkg = p.Name
	fmt.Fprintln(w, copyright)
	fmt.Fprintln(w, genLine)
	fmt.Fprintln(w)
	fmt.Fprintf(w, "package %s\n", pkgName())
	fmt.Fprintln(w)
	fmt.Fprintf(w, "import %q", p.PkgPath)
	fmt.Fprintln(w)
	}

	for _, d := range f.Decls {
	switch x := d.(type) {
	case *ast.FuncDecl:
	e.reportFun(w, x)
	case *ast.GenDecl:
	e.reportDecl(w, x)
	}
	}
	}
	}
	flushFile()
	}

	func (e extracter) reportFun(w io.Writer, x ast.FuncDecl) {
	if filter(x.Name.Name) {
	return
	}
	pkgName := e.pkg.Name
	override := ""
	params := []ast.Expr{}
	if x.Type.Params != nil {
	for _, f := range x.Type.Params.List {
	tx := f.Type
	if star, isStar := tx.(*ast.StarExpr); isStar {
	if i, ok := star.X.(*ast.Ident); ok && ast.IsExported(i.Name) {
	f.Type = &ast.SelectorExpr{X: ast.NewIdent(pkgName), Sel: i}
	if isStar {
	f.Type = &ast.StarExpr{X: f.Type}
	}
	}
	}
	for _, n := range f.Names {
	params = append(params, n)
	if n.Name == pkgName {
	override = pkgName + x.Name.Name
	}
	}
	}
	}
	var fn ast.Expr = &ast.SelectorExpr{
	X: ast.NewIdent(pkgName),
	Sel: x.Name,
	}
	if override != "" {
	fn = ast.NewIdent(override)
	}
	x.Body = &ast.BlockStmt{List: []ast.Stmt{
	&ast.ReturnStmt{Results: []ast.Expr{&ast.CallExpr{
	Fun: fn,
	Args: params,
	}}},
	}}
	if name := x.Name.Name; *stripstr && strings.HasSuffix(name, "String") {
	newName := name[:len(name)-len("String")]
	x.Name = ast.NewIdent(newName)
	if x.Doc != nil {
	for _, c := range x.Doc.List {
	c.Text = strings.Replace(c.Text, name, newName, -1)
	}
	}
	}
	types := []ast.Expr{}
	if x.Recv == nil && x.Type != nil && x.Type.Results != nil && !strings.HasPrefix(x.Name.Name, "New") {
	for _, f := range x.Type.Results.List {
	if len(f.Names) == 0 {
	types = append(types, f.Type)
	} else {
	for range f.Names {
	types = append(types, f.Type)
	}
	}
	}
	}
	if len(types) != 1 {
	switch len(types) {
	case 2:
	if i, ok := types[1].(*ast.Ident); ok && i.Name == "error" {
	break
	}
	fallthrough
	default:
	fmt.Printf("Skipping ")
	x.Doc = nil
	printer.Fprint(os.Stdout, e.pkg.Fset, x)
	fmt.Println()
	return
	}
	}
	fmt.Fprintln(w)
	printer.Fprint(w, e.pkg.Fset, x.Doc)
	printer.Fprint(w, e.pkg.Fset, x)
	fmt.Fprint(w, "\n")
	if override != "" {
	fmt.Fprintf(w, "var %s = %s.%s\n\n", override, pkgName, x.Name.Name)
	}
	}

	func (e extracter) reportDecl(w io.Writer, x ast.GenDecl) {
	if x.Tok != token.CONST {
	return
	}
	k := 0
	for _, s := range x.Specs {
	if v, ok := s.(*ast.ValueSpec); ok && !filter(v.Names[0].Name) {
	if v.Values == nil {
	v.Values = make([]ast.Expr, len(v.Names))
	}
	for i, expr := range v.Names {
	// This check can be removed if we set constants to floats.
	if _, ok := v.Values[i].(*ast.BasicLit); ok {
	continue
	}
	tv, _ := types.Eval(e.pkg.Fset, e.pkg.Types, v.Pos(), v.Names[0].Name)
	tok := token.ILLEGAL
	switch tv.Value.Kind() {
	case constant.Bool:
	v.Values[i] = ast.NewIdent(tv.Value.ExactString())
	continue
	case constant.String:
	tok = token.STRING
	case constant.Int:
	tok = token.INT
	case constant.Float:
	tok = token.FLOAT
	default:
	fmt.Printf("Skipping %s\n", v.Names)
	continue
	}
	v.Values[i] = &ast.BasicLit{
	ValuePos: expr.Pos(),
	Kind: tok,
	Value: tv.Value.ExactString(),
	}
	}
	v.Type = nil
	x.Specs[k] = v
	k++
	}
	}
	x.Specs = x.Specs[:k]
	if len(x.Specs) == 0 {
	return
	}
	fmt.Fprintln(w)
	printer.Fprint(w, e.pkg.Fset, x)
	fmt.Fprintln(w)
	}