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| // 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.
// Api computes the exported API of a set of Go packages.
package main
import (
"bufio"
"bytes"
"encoding/json"
"flag"
"fmt"
"go/ast"
"go/build"
"go/parser"
"go/token"
"go/types"
"io"
"log"
"os"
"os/exec"
"path/filepath"
"regexp"
"runtime"
"sort"
"strconv"
"strings"
"sync"
)
func goCmd() string {
var exeSuffix string
if runtime.GOOS == "windows" {
exeSuffix = ".exe"
}
if goroot := build.Default.GOROOT; goroot != "" {
path := filepath.Join(goroot, "bin", "go"+exeSuffix)
if _, err := os.Stat(path); err == nil {
return path
}
}
return "go"
}
// Flags
var (
checkFiles = flag.String("c", "", "optional comma-separated filename(s) to check API against")
requireApproval = flag.String("approval", "", "require approvals in comma-separated list of `files`")
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")
nextFiles = flag.String("next", "", "comma-separated list of `files` for upcoming API features for the next release. These files can be lazily maintained. They 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: "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: "netbsd", GOARCH: "arm64", CgoEnabled: true},
{GOOS: "netbsd", GOARCH: "arm64"},
{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 {
s += "-cgo"
}
if c.Dir != "" {
s += fmt.Sprintf(" [%s]", c.Dir)
}
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 build.Default.GOROOT == "" {
log.Fatalf("GOROOT not found. (If binary was built with -trimpath, $GOROOT must be set.)")
}
if !strings.Contains(runtime.Version(), "weekly") && !strings.Contains(runtime.Version(), "devel") {
if *nextFiles != "" {
fmt.Printf("Go version is %q, ignoring -next %s\n", runtime.Version(), *nextFiles)
*nextFiles = ""
}
}
if *forceCtx != "" {
setContexts()
}
for _, c := range contexts {
c.Compiler = build.Default.Compiler
}
walkers := make([]*Walker, len(contexts))
var wg sync.WaitGroup
for i, context := range contexts {
i, context := i, context
wg.Add(1)
go func() {
defer wg.Done()
walkers[i] = NewWalker(context, filepath.Join(build.Default.GOROOT, "src"))
}()
}
wg.Wait()
var featureCtx = make(map[string]map[string]bool) // feature -> context name -> true
for _, w := range walkers {
pkgNames := w.stdPackages
if flag.NArg() > 0 {
pkgNames = flag.Args()
}
for _, name := range pkgNames {
pkg, err := w.Import(name)
if _, nogo := err.(*build.NoGoError); nogo {
continue
}
if err != nil {
log.Fatalf("Import(%q): %v", name, err)
}
w.export(pkg)
}
ctxName := contextName(w.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 *checkFiles == "" {
sort.Strings(features)
for _, f := range features {
fmt.Fprintln(bw, f)
}
return
}
var required []string
for _, file := range strings.Split(*checkFiles, ",") {
required = append(required, fileFeatures(file)...)
}
var optional []string
if *nextFiles != "" {
for _, file := range strings.Split(*nextFiles, ",") {
optional = append(optional, fileFeatures(file)...)
}
}
exception := fileFeatures(*exceptFile)
fail = !compareAPI(bw, features, required, optional, exception, *allowNew)
}
// 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 token.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, "")
}
// portRemoved reports whether the given port-specific API feature is
// okay to no longer exist because its port was removed.
func portRemoved(feature string) bool {
return strings.Contains(feature, "(darwin-386)") ||
strings.Contains(feature, "(darwin-386-cgo)")
}
func compareAPI(w io.Writer, features, required, optional, exception []string, allowAdd bool) (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 portRemoved(feature) {
// okay.
} 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 !allowAdd {
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
}
// aliasReplacer applies type aliases to earlier API files,
// to avoid misleading negative results.
// This makes all the references to os.FileInfo in go1.txt
// be read as if they said fs.FileInfo, since os.FileInfo is now an alias.
// If there are many of these, we could do a more general solution,
// but for now the replacer is fine.
var aliasReplacer = strings.NewReplacer(
"os.FileInfo", "fs.FileInfo",
"os.FileMode", "fs.FileMode",
"os.PathError", "fs.PathError",
)
func fileFeatures(filename string) []string {
if filename == "" {
return nil
}
needApproval := false
for _, name := range strings.Split(*requireApproval, ",") {
if filename == name {
needApproval = true
break
}
}
bs, err := os.ReadFile(filename)
if err != nil {
log.Fatalf("Error reading file %s: %v", filename, err)
}
s := string(bs)
s = aliasReplacer.Replace(s)
lines := strings.Split(s, "\n")
var nonblank []string
for i, line := range lines {
line = strings.TrimSpace(line)
if line == "" || strings.HasPrefix(line, "#") {
continue
}
if needApproval {
feature, approval, ok := strings.Cut(line, "#")
if !ok {
log.Fatalf("%s:%d: missing proposal approval\n", filename, i+1)
}
_, err := strconv.Atoi(approval)
if err != nil {
log.Fatalf("%s:%d: malformed proposal approval #%s\n", filename, i+1, approval)
}
line = strings.TrimSpace(feature)
}
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
stdPackages []string // names, omitting "unsafe", internal, and vendored packages
importMap map[string]map[string]string // importer dir -> import path -> canonical path
importDir map[string]string // canonical import path -> dir
}
func NewWalker(context *build.Context, root string) *Walker {
w := &Walker{
context: context,
root: root,
features: map[string]bool{},
imported: map[string]*types.Package{"unsafe": types.Unsafe},
}
w.loadImports()
return w
}
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
}
// 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 plus GOOS and GOARCH) 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
// explicit on GOOS and GOARCH as global cache will use "all" cached packages for
// an indirect imported package. See https://github.com/golang/go/issues/21181
// for more detail.
tags = append(tags, context.GOOS, context.GOARCH)
sort.Strings(tags)
for _, tag := range tags {
if ctags[tag] {
key += "," + tag
ctags[tag] = false
}
}
return key
}
type listImports struct {
stdPackages []string // names, omitting "unsafe", internal, and vendored packages
importDir map[string]string // canonical import path → directory
importMap map[string]map[string]string // import path → canonical import path
}
var listCache sync.Map // map[string]listImports, keyed by contextName
// listSem is a semaphore restricting concurrent invocations of 'go list'. 'go
// list' has its own internal concurrency, so we use a hard-coded constant (to
// allow the I/O-intensive phases of 'go list' to overlap) instead of scaling
// all the way up to GOMAXPROCS.
var listSem = make(chan semToken, 2)
type semToken struct{}
// loadImports populates w with information about the packages in the standard
// library and the packages they themselves import in w's build context.
//
// The source import path and expanded import path are identical except for vendored packages.
// For example, on return:
//
// w.importMap["math"] = "math"
// w.importDir["math"] = "<goroot>/src/math"
//
// w.importMap["golang.org/x/net/route"] = "vendor/golang.org/x/net/route"
// w.importDir["vendor/golang.org/x/net/route"] = "<goroot>/src/vendor/golang.org/x/net/route"
//
// Since the set of packages that exist depends on context, the result of
// loadImports also depends on context. However, to improve test running time
// the configuration for each environment is cached across runs.
func (w *Walker) loadImports() {
if w.context == nil {
return // test-only Walker; does not use the import map
}
name := contextName(w.context)
imports, ok := listCache.Load(name)
if !ok {
listSem <- semToken{}
defer func() { <-listSem }()
cmd := exec.Command(goCmd(), "list", "-e", "-deps", "-json", "std")
cmd.Env = listEnv(w.context)
if w.context.Dir != "" {
cmd.Dir = w.context.Dir
}
out, err := cmd.CombinedOutput()
if err != nil {
log.Fatalf("loading imports: %v\n%s", err, out)
}
var stdPackages []string
importMap := make(map[string]map[string]string)
importDir := make(map[string]string)
dec := json.NewDecoder(bytes.NewReader(out))
for {
var pkg struct {
ImportPath, Dir string
ImportMap map[string]string
Standard bool
}
err := dec.Decode(&pkg)
if err == io.EOF {
break
}
if err != nil {
log.Fatalf("go list: invalid output: %v", err)
}
// - Package "unsafe" contains special signatures requiring
// extra care when printing them - ignore since it is not
// going to change w/o a language change.
// - Internal and vendored packages do not contribute to our
// API surface. (If we are running within the "std" module,
// vendored dependencies appear as themselves instead of
// their "vendor/" standard-library copies.)
// - 'go list std' does not include commands, which cannot be
// imported anyway.
if ip := pkg.ImportPath; pkg.Standard && ip != "unsafe" && !strings.HasPrefix(ip, "vendor/") && !internalPkg.MatchString(ip) {
stdPackages = append(stdPackages, ip)
}
importDir[pkg.ImportPath] = pkg.Dir
if len(pkg.ImportMap) > 0 {
importMap[pkg.Dir] = make(map[string]string, len(pkg.ImportMap))
}
for k, v := range pkg.ImportMap {
importMap[pkg.Dir][k] = v
}
}
sort.Strings(stdPackages)
imports = listImports{
stdPackages: stdPackages,
importMap: importMap,
importDir: importDir,
}
imports, _ = listCache.LoadOrStore(name, imports)
}
li := imports.(listImports)
w.stdPackages = li.stdPackages
w.importDir = li.importDir
w.importMap = li.importMap
}
// listEnv returns the process environment to use when invoking 'go list' for
// the given context.
func listEnv(c *build.Context) []string {
if c == nil {
return os.Environ()
}
environ := append(os.Environ(),
"GOOS="+c.GOOS,
"GOARCH="+c.GOARCH)
if c.CgoEnabled {
environ = append(environ, "CGO_ENABLED=1")
} else {
environ = append(environ, "CGO_ENABLED=0")
}
return environ
}
// 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) (*types.Package, error) {
return w.ImportFrom(name, "", 0)
}
func (w *Walker) ImportFrom(fromPath, fromDir string, mode types.ImportMode) (*types.Package, error) {
name := fromPath
if canonical, ok := w.importMap[fromDir][fromPath]; ok {
name = canonical
}
pkg := w.imported[name]
if pkg != nil {
if pkg == &importing {
log.Fatalf("cycle importing package %q", name)
}
return pkg, nil
}
w.imported[name] = &importing
// Determine package files.
dir := w.importDir[name]
if dir == "" {
dir = filepath.Join(w.root, filepath.FromSlash(name))
}
if fi, err := os.Stat(dir); err != nil || !fi.IsDir() {
log.Panicf("no source in tree for import %q (from import %s in %s): %v", name, fromPath, fromDir, err)
}
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, nil
}
}
}
info, err := context.ImportDir(dir, 0)
if err != nil {
if _, nogo := err.(*build.NoGoError); nogo {
return nil, err
}
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.
var sizes types.Sizes
if w.context != nil {
sizes = types.SizesFor(w.context.Compiler, w.context.GOARCH)
}
conf := types.Config{
IgnoreFuncBodies: true,
FakeImportC: true,
Importer: w,
Sizes: sizes,
}
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 pkg, nil
}
// 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
}
// sortedEmbeddeds returns constraint types embedded in an
// interface. It does not include embedded interface types or methods.
func (w *Walker) sortedEmbeddeds(typ *types.Interface) []string {
n := typ.NumEmbeddeds()
list := make([]string, 0, n)
for i := 0; i < n; i++ {
emb := typ.EmbeddedType(i)
switch emb := emb.(type) {
case *types.Interface:
list = append(list, w.sortedEmbeddeds(emb)...)
case *types.Union:
var buf bytes.Buffer
nu := emb.Len()
for i := 0; i < nu; i++ {
if i > 0 {
buf.WriteString(" | ")
}
term := emb.Term(i)
if term.Tilde() {
buf.WriteByte('~')
}
w.writeType(&buf, term.Type())
}
list = append(list, buf.String())
}
}
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 || typ.NumEmbeddeds() > 0 {
buf.WriteByte(' ')
}
if typ.NumMethods() > 0 {
buf.WriteString(strings.Join(sortedMethodNames(typ), ", "))
}
if typ.NumEmbeddeds() > 0 {
buf.WriteString(strings.Join(w.sortedEmbeddeds(typ), ", "))
}
if typ.NumMethods() > 0 || typ.NumEmbeddeds() > 0 {
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())
case *types.TypeParam:
// Type parameter names may change, so use a placeholder instead.
fmt.Fprintf(buf, "$%d", typ.Index())
default:
panic(fmt.Sprintf("unknown type %T", typ))
}
}
func (w *Walker) writeSignature(buf *bytes.Buffer, sig *types.Signature) {
if tparams := sig.TypeParams(); tparams != nil {
w.writeTypeParams(buf, tparams, true)
}
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) writeTypeParams(buf *bytes.Buffer, tparams *types.TypeParamList, withConstraints bool) {
buf.WriteByte('[')
c := tparams.Len()
for i := 0; i < c; i++ {
if i > 0 {
buf.WriteString(", ")
}
tp := tparams.At(i)
w.writeType(buf, tp)
if withConstraints {
buf.WriteByte(' ')
w.writeType(buf, tp.Constraint())
}
}
buf.WriteByte(']')
}
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()))
x := obj.Val()
short := x.String()
exact := x.ExactString()
if short == exact {
w.emitf("const %s = %s", obj.Name(), short)
} else {
w.emitf("const %s = %s // %s", obj.Name(), short, exact)
}
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()
if tparams := obj.Type().(*types.Named).TypeParams(); tparams != nil {
var buf bytes.Buffer
buf.WriteString(name)
w.writeTypeParams(&buf, tparams, true)
name = buf.String()
}
typ := obj.Type()
if obj.IsAlias() {
w.emitf("type %s = %s", name, w.typeString(typ))
return
}
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)
}
}
tps := ""
if rtp := sig.RecvTypeParams(); rtp != nil {
var buf bytes.Buffer
w.writeTypeParams(&buf, rtp, false)
tps = buf.String()
}
w.emitf("method (%s%s) %s%s", w.typeString(recv), tps, m.Obj().Name(), w.signatureString(sig))
}
func (w *Walker) emitf(format string, args ...any) {
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)
}
}
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