blob: 1f9c942e5cc8ef1d920d20e83e27ddfb6ca2b2fe [file] [log] [blame]
// 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 " + strings.Join(os.Args, " ")
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)
}