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go/src/cmd/api/goapi.go
Robert Griesemer b2a1fb74f4 cmd/api: update api checker to use go/types from std repo
The old code checked out a specific version of go/types from the
x/tools repo. With go/types being part of the std repo, this is
not necessary anymore.

Also, for the same reason, the api tool is now built like any
other regular command. There's no need to build it for each run.
Removed the respective +build tags.

Change-Id: I5088e4867223d676957084c24651ec05452ac495
Reviewed-on: https://go-review.googlesource.com/8564
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-04-08 04:09:34 +00:00

831 lines
20 KiB
Go

// Copyright 2011 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.
// Binary api computes the exported API of a set of Go packages.
package main
import (
"bufio"
"bytes"
"flag"
"fmt"
"go/ast"
"go/build"
"go/parser"
"go/token"
"go/types"
"io"
"io/ioutil"
"log"
"os"
"os/exec"
"path/filepath"
"regexp"
"runtime"
"sort"
"strings"
)
// Flags
var (
checkFile = flag.String("c", "", "optional comma-separated filename(s) to check API against")
allowNew = flag.Bool("allow_new", true, "allow API additions")
exceptFile = flag.String("except", "", "optional filename of packages that are allowed to change without triggering a failure in the tool")
nextFile = flag.String("next", "", "optional filename of tentative upcoming API features for the next release. This file can be lazily maintained. It only affects the delta warnings from the -c file printed on success.")
verbose = flag.Bool("v", false, "verbose debugging")
forceCtx = flag.String("contexts", "", "optional comma-separated list of <goos>-<goarch>[-cgo] to override default contexts.")
)
// contexts are the default contexts which are scanned, unless
// overridden by the -contexts flag.
var contexts = []*build.Context{
{GOOS: "linux", GOARCH: "386", CgoEnabled: true},
{GOOS: "linux", GOARCH: "386"},
{GOOS: "linux", GOARCH: "amd64", CgoEnabled: true},
{GOOS: "linux", GOARCH: "amd64"},
{GOOS: "linux", GOARCH: "arm", CgoEnabled: true},
{GOOS: "linux", GOARCH: "arm"},
{GOOS: "darwin", GOARCH: "386", CgoEnabled: true},
{GOOS: "darwin", GOARCH: "386"},
{GOOS: "darwin", GOARCH: "amd64", CgoEnabled: true},
{GOOS: "darwin", GOARCH: "amd64"},
{GOOS: "windows", GOARCH: "amd64"},
{GOOS: "windows", GOARCH: "386"},
{GOOS: "freebsd", GOARCH: "386", CgoEnabled: true},
{GOOS: "freebsd", GOARCH: "386"},
{GOOS: "freebsd", GOARCH: "amd64", CgoEnabled: true},
{GOOS: "freebsd", GOARCH: "amd64"},
{GOOS: "freebsd", GOARCH: "arm", CgoEnabled: true},
{GOOS: "freebsd", GOARCH: "arm"},
{GOOS: "netbsd", GOARCH: "386", CgoEnabled: true},
{GOOS: "netbsd", GOARCH: "386"},
{GOOS: "netbsd", GOARCH: "amd64", CgoEnabled: true},
{GOOS: "netbsd", GOARCH: "amd64"},
{GOOS: "netbsd", GOARCH: "arm", CgoEnabled: true},
{GOOS: "netbsd", GOARCH: "arm"},
{GOOS: "openbsd", GOARCH: "386", CgoEnabled: true},
{GOOS: "openbsd", GOARCH: "386"},
{GOOS: "openbsd", GOARCH: "amd64", CgoEnabled: true},
{GOOS: "openbsd", GOARCH: "amd64"},
}
func contextName(c *build.Context) string {
s := c.GOOS + "-" + c.GOARCH
if c.CgoEnabled {
return s + "-cgo"
}
return s
}
func parseContext(c string) *build.Context {
parts := strings.Split(c, "-")
if len(parts) < 2 {
log.Fatalf("bad context: %q", c)
}
bc := &build.Context{
GOOS: parts[0],
GOARCH: parts[1],
}
if len(parts) == 3 {
if parts[2] == "cgo" {
bc.CgoEnabled = true
} else {
log.Fatalf("bad context: %q", c)
}
}
return bc
}
func setContexts() {
contexts = []*build.Context{}
for _, c := range strings.Split(*forceCtx, ",") {
contexts = append(contexts, parseContext(c))
}
}
var internalPkg = regexp.MustCompile(`(^|/)internal($|/)`)
func main() {
flag.Parse()
if !strings.Contains(runtime.Version(), "weekly") && !strings.Contains(runtime.Version(), "devel") {
if *nextFile != "" {
fmt.Printf("Go version is %q, ignoring -next %s\n", runtime.Version(), *nextFile)
*nextFile = ""
}
}
if *forceCtx != "" {
setContexts()
}
for _, c := range contexts {
c.Compiler = build.Default.Compiler
}
var pkgNames []string
if flag.NArg() > 0 {
pkgNames = flag.Args()
} else {
stds, err := exec.Command("go", "list", "std").Output()
if err != nil {
log.Fatal(err)
}
for _, pkg := range strings.Fields(string(stds)) {
if !internalPkg.MatchString(pkg) {
pkgNames = append(pkgNames, pkg)
}
}
}
var featureCtx = make(map[string]map[string]bool) // feature -> context name -> true
for _, context := range contexts {
w := NewWalker(context, filepath.Join(build.Default.GOROOT, "src"))
for _, name := range pkgNames {
// - Package "unsafe" contains special signatures requiring
// extra care when printing them - ignore since it is not
// going to change w/o a language change.
// - We don't care about the API of commands.
if name != "unsafe" && !strings.HasPrefix(name, "cmd/") {
if name == "runtime/cgo" && !context.CgoEnabled {
// w.Import(name) will return nil
continue
}
w.export(w.Import(name))
}
}
ctxName := contextName(context)
for _, f := range w.Features() {
if featureCtx[f] == nil {
featureCtx[f] = make(map[string]bool)
}
featureCtx[f][ctxName] = true
}
}
var features []string
for f, cmap := range featureCtx {
if len(cmap) == len(contexts) {
features = append(features, f)
continue
}
comma := strings.Index(f, ",")
for cname := range cmap {
f2 := fmt.Sprintf("%s (%s)%s", f[:comma], cname, f[comma:])
features = append(features, f2)
}
}
fail := false
defer func() {
if fail {
os.Exit(1)
}
}()
bw := bufio.NewWriter(os.Stdout)
defer bw.Flush()
if *checkFile == "" {
sort.Strings(features)
for _, f := range features {
fmt.Fprintln(bw, f)
}
return
}
var required []string
for _, file := range strings.Split(*checkFile, ",") {
required = append(required, fileFeatures(file)...)
}
optional := fileFeatures(*nextFile)
exception := fileFeatures(*exceptFile)
fail = !compareAPI(bw, features, required, optional, exception)
}
// export emits the exported package features.
func (w *Walker) export(pkg *types.Package) {
if *verbose {
log.Println(pkg)
}
pop := w.pushScope("pkg " + pkg.Path())
w.current = pkg
scope := pkg.Scope()
for _, name := range scope.Names() {
if ast.IsExported(name) {
w.emitObj(scope.Lookup(name))
}
}
pop()
}
func set(items []string) map[string]bool {
s := make(map[string]bool)
for _, v := range items {
s[v] = true
}
return s
}
var spaceParensRx = regexp.MustCompile(` \(\S+?\)`)
func featureWithoutContext(f string) string {
if !strings.Contains(f, "(") {
return f
}
return spaceParensRx.ReplaceAllString(f, "")
}
func compareAPI(w io.Writer, features, required, optional, exception []string) (ok bool) {
ok = true
optionalSet := set(optional)
exceptionSet := set(exception)
featureSet := set(features)
sort.Strings(features)
sort.Strings(required)
take := func(sl *[]string) string {
s := (*sl)[0]
*sl = (*sl)[1:]
return s
}
for len(required) > 0 || len(features) > 0 {
switch {
case len(features) == 0 || (len(required) > 0 && required[0] < features[0]):
feature := take(&required)
if exceptionSet[feature] {
// An "unfortunate" case: the feature was once
// included in the API (e.g. go1.txt), but was
// subsequently removed. These are already
// acknowledged by being in the file
// "api/except.txt". No need to print them out
// here.
} else if featureSet[featureWithoutContext(feature)] {
// okay.
} else {
fmt.Fprintf(w, "-%s\n", feature)
ok = false // broke compatibility
}
case len(required) == 0 || (len(features) > 0 && required[0] > features[0]):
newFeature := take(&features)
if optionalSet[newFeature] {
// Known added feature to the upcoming release.
// Delete it from the map so we can detect any upcoming features
// which were never seen. (so we can clean up the nextFile)
delete(optionalSet, newFeature)
} else {
fmt.Fprintf(w, "+%s\n", newFeature)
if !*allowNew || !strings.Contains(runtime.Version(), "devel") {
ok = false // we're in lock-down mode for next release
}
}
default:
take(&required)
take(&features)
}
}
// In next file, but not in API.
var missing []string
for feature := range optionalSet {
missing = append(missing, feature)
}
sort.Strings(missing)
for _, feature := range missing {
fmt.Fprintf(w, "±%s\n", feature)
}
return
}
func fileFeatures(filename string) []string {
if filename == "" {
return nil
}
bs, err := ioutil.ReadFile(filename)
if err != nil {
log.Fatalf("Error reading file %s: %v", filename, err)
}
lines := strings.Split(string(bs), "\n")
var nonblank []string
for _, line := range lines {
line = strings.TrimSpace(line)
if line != "" && !strings.HasPrefix(line, "#") {
nonblank = append(nonblank, line)
}
}
return nonblank
}
var fset = token.NewFileSet()
type Walker struct {
context *build.Context
root string
scope []string
current *types.Package
features map[string]bool // set
imported map[string]*types.Package // packages already imported
}
func NewWalker(context *build.Context, root string) *Walker {
return &Walker{
context: context,
root: root,
features: map[string]bool{},
imported: map[string]*types.Package{"unsafe": types.Unsafe},
}
}
func (w *Walker) Features() (fs []string) {
for f := range w.features {
fs = append(fs, f)
}
sort.Strings(fs)
return
}
var parsedFileCache = make(map[string]*ast.File)
func (w *Walker) parseFile(dir, file string) (*ast.File, error) {
filename := filepath.Join(dir, file)
if f := parsedFileCache[filename]; f != nil {
return f, nil
}
f, err := parser.ParseFile(fset, filename, nil, 0)
if err != nil {
return nil, err
}
parsedFileCache[filename] = f
return f, nil
}
func contains(list []string, s string) bool {
for _, t := range list {
if t == s {
return true
}
}
return false
}
// The package cache doesn't operate correctly in rare (so far artificial)
// circumstances (issue 8425). Disable before debugging non-obvious errors
// from the type-checker.
const usePkgCache = true
var (
pkgCache = map[string]*types.Package{} // map tagKey to package
pkgTags = map[string][]string{} // map import dir to list of relevant tags
)
// tagKey returns the tag-based key to use in the pkgCache.
// It is a comma-separated string; the first part is dir, the rest tags.
// The satisfied tags are derived from context but only those that
// matter (the ones listed in the tags argument) are used.
// The tags list, which came from go/build's Package.AllTags,
// is known to be sorted.
func tagKey(dir string, context *build.Context, tags []string) string {
ctags := map[string]bool{
context.GOOS: true,
context.GOARCH: true,
}
if context.CgoEnabled {
ctags["cgo"] = true
}
for _, tag := range context.BuildTags {
ctags[tag] = true
}
// TODO: ReleaseTags (need to load default)
key := dir
for _, tag := range tags {
if ctags[tag] {
key += "," + tag
}
}
return key
}
// Importing is a sentinel taking the place in Walker.imported
// for a package that is in the process of being imported.
var importing types.Package
func (w *Walker) Import(name string) (pkg *types.Package) {
pkg = w.imported[name]
if pkg != nil {
if pkg == &importing {
log.Fatalf("cycle importing package %q", name)
}
return pkg
}
w.imported[name] = &importing
// Determine package files.
dir := filepath.Join(w.root, filepath.FromSlash(name))
if fi, err := os.Stat(dir); err != nil || !fi.IsDir() {
log.Fatalf("no source in tree for package %q", pkg)
}
context := w.context
if context == nil {
context = &build.Default
}
// Look in cache.
// If we've already done an import with the same set
// of relevant tags, reuse the result.
var key string
if usePkgCache {
if tags, ok := pkgTags[dir]; ok {
key = tagKey(dir, context, tags)
if pkg := pkgCache[key]; pkg != nil {
w.imported[name] = pkg
return pkg
}
}
}
info, err := context.ImportDir(dir, 0)
if err != nil {
if _, nogo := err.(*build.NoGoError); nogo {
return
}
log.Fatalf("pkg %q, dir %q: ScanDir: %v", name, dir, err)
}
// Save tags list first time we see a directory.
if usePkgCache {
if _, ok := pkgTags[dir]; !ok {
pkgTags[dir] = info.AllTags
key = tagKey(dir, context, info.AllTags)
}
}
filenames := append(append([]string{}, info.GoFiles...), info.CgoFiles...)
// Parse package files.
var files []*ast.File
for _, file := range filenames {
f, err := w.parseFile(dir, file)
if err != nil {
log.Fatalf("error parsing package %s: %s", name, err)
}
files = append(files, f)
}
// Type-check package files.
conf := types.Config{
IgnoreFuncBodies: true,
FakeImportC: true,
Import: func(imports map[string]*types.Package, name string) (*types.Package, error) {
pkg := w.Import(name)
imports[name] = pkg
return pkg, nil
},
}
pkg, err = conf.Check(name, fset, files, nil)
if err != nil {
ctxt := "<no context>"
if w.context != nil {
ctxt = fmt.Sprintf("%s-%s", w.context.GOOS, w.context.GOARCH)
}
log.Fatalf("error typechecking package %s: %s (%s)", name, err, ctxt)
}
if usePkgCache {
pkgCache[key] = pkg
}
w.imported[name] = pkg
return
}
// pushScope enters a new scope (walking a package, type, node, etc)
// and returns a function that will leave the scope (with sanity checking
// for mismatched pushes & pops)
func (w *Walker) pushScope(name string) (popFunc func()) {
w.scope = append(w.scope, name)
return func() {
if len(w.scope) == 0 {
log.Fatalf("attempt to leave scope %q with empty scope list", name)
}
if w.scope[len(w.scope)-1] != name {
log.Fatalf("attempt to leave scope %q, but scope is currently %#v", name, w.scope)
}
w.scope = w.scope[:len(w.scope)-1]
}
}
func sortedMethodNames(typ *types.Interface) []string {
n := typ.NumMethods()
list := make([]string, n)
for i := range list {
list[i] = typ.Method(i).Name()
}
sort.Strings(list)
return list
}
func (w *Walker) writeType(buf *bytes.Buffer, typ types.Type) {
switch typ := typ.(type) {
case *types.Basic:
s := typ.Name()
switch typ.Kind() {
case types.UnsafePointer:
s = "unsafe.Pointer"
case types.UntypedBool:
s = "ideal-bool"
case types.UntypedInt:
s = "ideal-int"
case types.UntypedRune:
// "ideal-char" for compatibility with old tool
// TODO(gri) change to "ideal-rune"
s = "ideal-char"
case types.UntypedFloat:
s = "ideal-float"
case types.UntypedComplex:
s = "ideal-complex"
case types.UntypedString:
s = "ideal-string"
case types.UntypedNil:
panic("should never see untyped nil type")
default:
switch s {
case "byte":
s = "uint8"
case "rune":
s = "int32"
}
}
buf.WriteString(s)
case *types.Array:
fmt.Fprintf(buf, "[%d]", typ.Len())
w.writeType(buf, typ.Elem())
case *types.Slice:
buf.WriteString("[]")
w.writeType(buf, typ.Elem())
case *types.Struct:
buf.WriteString("struct")
case *types.Pointer:
buf.WriteByte('*')
w.writeType(buf, typ.Elem())
case *types.Tuple:
panic("should never see a tuple type")
case *types.Signature:
buf.WriteString("func")
w.writeSignature(buf, typ)
case *types.Interface:
buf.WriteString("interface{")
if typ.NumMethods() > 0 {
buf.WriteByte(' ')
buf.WriteString(strings.Join(sortedMethodNames(typ), ", "))
buf.WriteByte(' ')
}
buf.WriteString("}")
case *types.Map:
buf.WriteString("map[")
w.writeType(buf, typ.Key())
buf.WriteByte(']')
w.writeType(buf, typ.Elem())
case *types.Chan:
var s string
switch typ.Dir() {
case types.SendOnly:
s = "chan<- "
case types.RecvOnly:
s = "<-chan "
case types.SendRecv:
s = "chan "
default:
panic("unreachable")
}
buf.WriteString(s)
w.writeType(buf, typ.Elem())
case *types.Named:
obj := typ.Obj()
pkg := obj.Pkg()
if pkg != nil && pkg != w.current {
buf.WriteString(pkg.Name())
buf.WriteByte('.')
}
buf.WriteString(typ.Obj().Name())
default:
panic(fmt.Sprintf("unknown type %T", typ))
}
}
func (w *Walker) writeSignature(buf *bytes.Buffer, sig *types.Signature) {
w.writeParams(buf, sig.Params(), sig.Variadic())
switch res := sig.Results(); res.Len() {
case 0:
// nothing to do
case 1:
buf.WriteByte(' ')
w.writeType(buf, res.At(0).Type())
default:
buf.WriteByte(' ')
w.writeParams(buf, res, false)
}
}
func (w *Walker) writeParams(buf *bytes.Buffer, t *types.Tuple, variadic bool) {
buf.WriteByte('(')
for i, n := 0, t.Len(); i < n; i++ {
if i > 0 {
buf.WriteString(", ")
}
typ := t.At(i).Type()
if variadic && i+1 == n {
buf.WriteString("...")
typ = typ.(*types.Slice).Elem()
}
w.writeType(buf, typ)
}
buf.WriteByte(')')
}
func (w *Walker) typeString(typ types.Type) string {
var buf bytes.Buffer
w.writeType(&buf, typ)
return buf.String()
}
func (w *Walker) signatureString(sig *types.Signature) string {
var buf bytes.Buffer
w.writeSignature(&buf, sig)
return buf.String()
}
func (w *Walker) emitObj(obj types.Object) {
switch obj := obj.(type) {
case *types.Const:
w.emitf("const %s %s", obj.Name(), w.typeString(obj.Type()))
w.emitf("const %s = %s", obj.Name(), obj.Val())
case *types.Var:
w.emitf("var %s %s", obj.Name(), w.typeString(obj.Type()))
case *types.TypeName:
w.emitType(obj)
case *types.Func:
w.emitFunc(obj)
default:
panic("unknown object: " + obj.String())
}
}
func (w *Walker) emitType(obj *types.TypeName) {
name := obj.Name()
typ := obj.Type()
switch typ := typ.Underlying().(type) {
case *types.Struct:
w.emitStructType(name, typ)
case *types.Interface:
w.emitIfaceType(name, typ)
return // methods are handled by emitIfaceType
default:
w.emitf("type %s %s", name, w.typeString(typ.Underlying()))
}
// emit methods with value receiver
var methodNames map[string]bool
vset := types.NewMethodSet(typ)
for i, n := 0, vset.Len(); i < n; i++ {
m := vset.At(i)
if m.Obj().Exported() {
w.emitMethod(m)
if methodNames == nil {
methodNames = make(map[string]bool)
}
methodNames[m.Obj().Name()] = true
}
}
// emit methods with pointer receiver; exclude
// methods that we have emitted already
// (the method set of *T includes the methods of T)
pset := types.NewMethodSet(types.NewPointer(typ))
for i, n := 0, pset.Len(); i < n; i++ {
m := pset.At(i)
if m.Obj().Exported() && !methodNames[m.Obj().Name()] {
w.emitMethod(m)
}
}
}
func (w *Walker) emitStructType(name string, typ *types.Struct) {
typeStruct := fmt.Sprintf("type %s struct", name)
w.emitf(typeStruct)
defer w.pushScope(typeStruct)()
for i := 0; i < typ.NumFields(); i++ {
f := typ.Field(i)
if !f.Exported() {
continue
}
typ := f.Type()
if f.Anonymous() {
w.emitf("embedded %s", w.typeString(typ))
continue
}
w.emitf("%s %s", f.Name(), w.typeString(typ))
}
}
func (w *Walker) emitIfaceType(name string, typ *types.Interface) {
pop := w.pushScope("type " + name + " interface")
var methodNames []string
complete := true
mset := types.NewMethodSet(typ)
for i, n := 0, mset.Len(); i < n; i++ {
m := mset.At(i).Obj().(*types.Func)
if !m.Exported() {
complete = false
continue
}
methodNames = append(methodNames, m.Name())
w.emitf("%s%s", m.Name(), w.signatureString(m.Type().(*types.Signature)))
}
if !complete {
// The method set has unexported methods, so all the
// implementations are provided by the same package,
// so the method set can be extended. Instead of recording
// the full set of names (below), record only that there were
// unexported methods. (If the interface shrinks, we will notice
// because a method signature emitted during the last loop
// will disappear.)
w.emitf("unexported methods")
}
pop()
if !complete {
return
}
if len(methodNames) == 0 {
w.emitf("type %s interface {}", name)
return
}
sort.Strings(methodNames)
w.emitf("type %s interface { %s }", name, strings.Join(methodNames, ", "))
}
func (w *Walker) emitFunc(f *types.Func) {
sig := f.Type().(*types.Signature)
if sig.Recv() != nil {
panic("method considered a regular function: " + f.String())
}
w.emitf("func %s%s", f.Name(), w.signatureString(sig))
}
func (w *Walker) emitMethod(m *types.Selection) {
sig := m.Type().(*types.Signature)
recv := sig.Recv().Type()
// report exported methods with unexported receiver base type
if true {
base := recv
if p, _ := recv.(*types.Pointer); p != nil {
base = p.Elem()
}
if obj := base.(*types.Named).Obj(); !obj.Exported() {
log.Fatalf("exported method with unexported receiver base type: %s", m)
}
}
w.emitf("method (%s) %s%s", w.typeString(recv), m.Obj().Name(), w.signatureString(sig))
}
func (w *Walker) emitf(format string, args ...interface{}) {
f := strings.Join(w.scope, ", ") + ", " + fmt.Sprintf(format, args...)
if strings.Contains(f, "\n") {
panic("feature contains newlines: " + f)
}
if _, dup := w.features[f]; dup {
panic("duplicate feature inserted: " + f)
}
w.features[f] = true
if *verbose {
log.Printf("feature: %s", f)
}
}