--- /dev/null
+// Copyright 2009 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.
+
+// godoc: Go Documentation Server
+
+// Web server tree:
+//
+// http://godoc/ redirect to /pkg/
+// http://godoc/src/ serve files from $GOROOT/src; .go gets pretty-printed
+// http://godoc/cmd/ serve documentation about commands
+// http://godoc/pkg/ serve documentation about packages
+// (idea is if you say import "compress/zlib", you go to
+// http://godoc/pkg/compress/zlib)
+//
+
+package main
+
+import (
+ "archive/zip"
+ "bytes"
+ "context"
+ "encoding/json"
+ _ "expvar" // to serve /debug/vars
+ "flag"
+ "fmt"
+ "go/build"
+ "io"
+ "log"
+ "net/http"
+ _ "net/http/pprof" // to serve /debug/pprof/*
+ "net/url"
+ "os"
+ "os/exec"
+ "path"
+ "path/filepath"
+ "regexp"
+ "runtime"
+ "strings"
+
+ "golang.org/x/tools/godoc"
+ "golang.org/x/tools/godoc/analysis"
+ "golang.org/x/tools/godoc/static"
+ "golang.org/x/tools/godoc/vfs"
+ "golang.org/x/tools/godoc/vfs/gatefs"
+ "golang.org/x/tools/godoc/vfs/mapfs"
+ "golang.org/x/tools/godoc/vfs/zipfs"
+ "golang.org/x/tools/internal/gocommand"
+ "golang.org/x/xerrors"
+)
+
+const defaultAddr = "localhost:6060" // default webserver address
+
+var (
+ // file system to serve
+ // (with e.g.: zip -r go.zip $GOROOT -i \*.go -i \*.html -i \*.css -i \*.js -i \*.txt -i \*.c -i \*.h -i \*.s -i \*.png -i \*.jpg -i \*.sh -i favicon.ico)
+ zipfile = flag.String("zip", "", "zip file providing the file system to serve; disabled if empty")
+
+ // file-based index
+ writeIndex = flag.Bool("write_index", false, "write index to a file; the file name must be specified with -index_files")
+
+ analysisFlag = flag.String("analysis", "", `comma-separated list of analyses to perform when in GOPATH mode (supported: type, pointer). See https://golang.org/lib/godoc/analysis/help.html`)
+
+ // network
+ httpAddr = flag.String("http", defaultAddr, "HTTP service address")
+
+ // layout control
+ urlFlag = flag.String("url", "", "print HTML for named URL")
+
+ verbose = flag.Bool("v", false, "verbose mode")
+
+ // file system roots
+ // TODO(gri) consider the invariant that goroot always end in '/'
+ goroot = flag.String("goroot", findGOROOT(), "Go root directory")
+
+ // layout control
+ showTimestamps = flag.Bool("timestamps", false, "show timestamps with directory listings")
+ templateDir = flag.String("templates", "", "load templates/JS/CSS from disk in this directory")
+ showPlayground = flag.Bool("play", false, "enable playground")
+ declLinks = flag.Bool("links", true, "link identifiers to their declarations")
+
+ // search index
+ indexEnabled = flag.Bool("index", false, "enable search index")
+ indexFiles = flag.String("index_files", "", "glob pattern specifying index files; if not empty, the index is read from these files in sorted order")
+ indexInterval = flag.Duration("index_interval", 0, "interval of indexing; 0 for default (5m), negative to only index once at startup")
+ maxResults = flag.Int("maxresults", 10000, "maximum number of full text search results shown")
+ indexThrottle = flag.Float64("index_throttle", 0.75, "index throttle value; 0.0 = no time allocated, 1.0 = full throttle")
+
+ // source code notes
+ notesRx = flag.String("notes", "BUG", "regular expression matching note markers to show")
+)
+
+// An httpResponseRecorder is an http.ResponseWriter
+type httpResponseRecorder struct {
+ body *bytes.Buffer
+ header http.Header
+ code int
+}
+
+func (w *httpResponseRecorder) Header() http.Header { return w.header }
+func (w *httpResponseRecorder) Write(b []byte) (int, error) { return w.body.Write(b) }
+func (w *httpResponseRecorder) WriteHeader(code int) { w.code = code }
+
+func usage() {
+ fmt.Fprintf(os.Stderr, "usage: godoc -http="+defaultAddr+"\n")
+ flag.PrintDefaults()
+ os.Exit(2)
+}
+
+func loggingHandler(h http.Handler) http.Handler {
+ return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+ log.Printf("%s\t%s", req.RemoteAddr, req.URL)
+ h.ServeHTTP(w, req)
+ })
+}
+
+func handleURLFlag() {
+ // Try up to 10 fetches, following redirects.
+ urlstr := *urlFlag
+ for i := 0; i < 10; i++ {
+ // Prepare request.
+ u, err := url.Parse(urlstr)
+ if err != nil {
+ log.Fatal(err)
+ }
+ req := &http.Request{
+ URL: u,
+ }
+
+ // Invoke default HTTP handler to serve request
+ // to our buffering httpWriter.
+ w := &httpResponseRecorder{code: 200, header: make(http.Header), body: new(bytes.Buffer)}
+ http.DefaultServeMux.ServeHTTP(w, req)
+
+ // Return data, error, or follow redirect.
+ switch w.code {
+ case 200: // ok
+ os.Stdout.Write(w.body.Bytes())
+ return
+ case 301, 302, 303, 307: // redirect
+ redirect := w.header.Get("Location")
+ if redirect == "" {
+ log.Fatalf("HTTP %d without Location header", w.code)
+ }
+ urlstr = redirect
+ default:
+ log.Fatalf("HTTP error %d", w.code)
+ }
+ }
+ log.Fatalf("too many redirects")
+}
+
+func initCorpus(corpus *godoc.Corpus) {
+ err := corpus.Init()
+ if err != nil {
+ log.Fatal(err)
+ }
+}
+
+func main() {
+ flag.Usage = usage
+ flag.Parse()
+
+ // Check usage.
+ if flag.NArg() > 0 {
+ fmt.Fprintln(os.Stderr, `Unexpected arguments. Use "go doc" for command-line help output instead. For example, "go doc fmt.Printf".`)
+ usage()
+ }
+ if *httpAddr == "" && *urlFlag == "" && !*writeIndex {
+ fmt.Fprintln(os.Stderr, "At least one of -http, -url, or -write_index must be set to a non-zero value.")
+ usage()
+ }
+
+ // Set the resolved goroot.
+ vfs.GOROOT = *goroot
+
+ fsGate := make(chan bool, 20)
+
+ // Determine file system to use.
+ if *zipfile == "" {
+ // use file system of underlying OS
+ rootfs := gatefs.New(vfs.OS(*goroot), fsGate)
+ fs.Bind("/", rootfs, "/", vfs.BindReplace)
+ } else {
+ // use file system specified via .zip file (path separator must be '/')
+ rc, err := zip.OpenReader(*zipfile)
+ if err != nil {
+ log.Fatalf("%s: %s\n", *zipfile, err)
+ }
+ defer rc.Close() // be nice (e.g., -writeIndex mode)
+ fs.Bind("/", zipfs.New(rc, *zipfile), *goroot, vfs.BindReplace)
+ }
+ if *templateDir != "" {
+ fs.Bind("/lib/godoc", vfs.OS(*templateDir), "/", vfs.BindBefore)
+ } else {
+ fs.Bind("/lib/godoc", mapfs.New(static.Files), "/", vfs.BindReplace)
+ }
+
+ // Get the GOMOD value, use it to determine if godoc is being invoked in module mode.
+ goModFile, err := goMod()
+ if err != nil {
+ fmt.Fprintf(os.Stderr, "failed to determine go env GOMOD value: %v", err)
+ goModFile = "" // Fall back to GOPATH mode.
+ }
+
+ if goModFile != "" {
+ fmt.Printf("using module mode; GOMOD=%s\n", goModFile)
+
+ if *analysisFlag != "" {
+ fmt.Fprintln(os.Stderr, "The -analysis flag is supported only in GOPATH mode at this time.")
+ fmt.Fprintln(os.Stderr, "See https://golang.org/issue/34473.")
+ usage()
+ }
+
+ // Detect whether to use vendor mode or not.
+ mainMod, vendorEnabled, err := gocommand.VendorEnabled(context.Background(), gocommand.Invocation{}, &gocommand.Runner{})
+ if err != nil {
+ fmt.Fprintf(os.Stderr, "failed to determine if vendoring is enabled: %v", err)
+ os.Exit(1)
+ }
+ if vendorEnabled {
+ // Bind the root directory of the main module.
+ fs.Bind(path.Join("/src", mainMod.Path), gatefs.New(vfs.OS(mainMod.Dir), fsGate), "/", vfs.BindAfter)
+
+ // Bind the vendor directory.
+ //
+ // Note that in module mode, vendor directories in locations
+ // other than the main module's root directory are ignored.
+ // See https://golang.org/ref/mod#vendoring.
+ vendorDir := filepath.Join(mainMod.Dir, "vendor")
+ fs.Bind("/src", gatefs.New(vfs.OS(vendorDir), fsGate), "/", vfs.BindAfter)
+
+ } else {
+ // Try to download dependencies that are not in the module cache in order to
+ // to show their documentation.
+ // This may fail if module downloading is disallowed (GOPROXY=off) or due to
+ // limited connectivity, in which case we print errors to stderr and show
+ // documentation only for packages that are available.
+ fillModuleCache(os.Stderr, goModFile)
+
+ // Determine modules in the build list.
+ mods, err := buildList(goModFile)
+ if err != nil {
+ fmt.Fprintf(os.Stderr, "failed to determine the build list of the main module: %v", err)
+ os.Exit(1)
+ }
+
+ // Bind module trees into Go root.
+ for _, m := range mods {
+ if m.Dir == "" {
+ // Module is not available in the module cache, skip it.
+ continue
+ }
+ dst := path.Join("/src", m.Path)
+ fs.Bind(dst, gatefs.New(vfs.OS(m.Dir), fsGate), "/", vfs.BindAfter)
+ }
+ }
+ } else {
+ fmt.Println("using GOPATH mode")
+
+ // Bind $GOPATH trees into Go root.
+ for _, p := range filepath.SplitList(build.Default.GOPATH) {
+ fs.Bind("/src", gatefs.New(vfs.OS(p), fsGate), "/src", vfs.BindAfter)
+ }
+ }
+
+ var typeAnalysis, pointerAnalysis bool
+ if *analysisFlag != "" {
+ for _, a := range strings.Split(*analysisFlag, ",") {
+ switch a {
+ case "type":
+ typeAnalysis = true
+ case "pointer":
+ pointerAnalysis = true
+ default:
+ log.Fatalf("unknown analysis: %s", a)
+ }
+ }
+ }
+
+ var corpus *godoc.Corpus
+ if goModFile != "" {
+ corpus = godoc.NewCorpus(moduleFS{fs})
+ } else {
+ corpus = godoc.NewCorpus(fs)
+ }
+ corpus.Verbose = *verbose
+ corpus.MaxResults = *maxResults
+ corpus.IndexEnabled = *indexEnabled
+ if *maxResults == 0 {
+ corpus.IndexFullText = false
+ }
+ corpus.IndexFiles = *indexFiles
+ corpus.IndexDirectory = func(dir string) bool {
+ return dir != "/pkg" && !strings.HasPrefix(dir, "/pkg/")
+ }
+ corpus.IndexThrottle = *indexThrottle
+ corpus.IndexInterval = *indexInterval
+ if *writeIndex || *urlFlag != "" {
+ corpus.IndexThrottle = 1.0
+ corpus.IndexEnabled = true
+ initCorpus(corpus)
+ } else {
+ go initCorpus(corpus)
+ }
+
+ // Initialize the version info before readTemplates, which saves
+ // the map value in a method value.
+ corpus.InitVersionInfo()
+
+ pres = godoc.NewPresentation(corpus)
+ pres.ShowTimestamps = *showTimestamps
+ pres.ShowPlayground = *showPlayground
+ pres.DeclLinks = *declLinks
+ if *notesRx != "" {
+ pres.NotesRx = regexp.MustCompile(*notesRx)
+ }
+
+ readTemplates(pres)
+ registerHandlers(pres)
+
+ if *writeIndex {
+ // Write search index and exit.
+ if *indexFiles == "" {
+ log.Fatal("no index file specified")
+ }
+
+ log.Println("initialize file systems")
+ *verbose = true // want to see what happens
+
+ corpus.UpdateIndex()
+
+ log.Println("writing index file", *indexFiles)
+ f, err := os.Create(*indexFiles)
+ if err != nil {
+ log.Fatal(err)
+ }
+ index, _ := corpus.CurrentIndex()
+ _, err = index.WriteTo(f)
+ if err != nil {
+ log.Fatal(err)
+ }
+
+ log.Println("done")
+ return
+ }
+
+ // Print content that would be served at the URL *urlFlag.
+ if *urlFlag != "" {
+ handleURLFlag()
+ return
+ }
+
+ var handler http.Handler = http.DefaultServeMux
+ if *verbose {
+ log.Printf("Go Documentation Server")
+ log.Printf("version = %s", runtime.Version())
+ log.Printf("address = %s", *httpAddr)
+ log.Printf("goroot = %s", *goroot)
+ switch {
+ case !*indexEnabled:
+ log.Print("search index disabled")
+ case *maxResults > 0:
+ log.Printf("full text index enabled (maxresults = %d)", *maxResults)
+ default:
+ log.Print("identifier search index enabled")
+ }
+ fs.Fprint(os.Stderr)
+ handler = loggingHandler(handler)
+ }
+
+ // Initialize search index.
+ if *indexEnabled {
+ go corpus.RunIndexer()
+ }
+
+ // Start type/pointer analysis.
+ if typeAnalysis || pointerAnalysis {
+ go analysis.Run(pointerAnalysis, &corpus.Analysis)
+ }
+
+ // Start http server.
+ if *verbose {
+ log.Println("starting HTTP server")
+ }
+ if err := http.ListenAndServe(*httpAddr, handler); err != nil {
+ log.Fatalf("ListenAndServe %s: %v", *httpAddr, err)
+ }
+}
+
+// goMod returns the go env GOMOD value in the current directory
+// by invoking the go command.
+//
+// GOMOD is documented at https://golang.org/cmd/go/#hdr-Environment_variables:
+//
+// The absolute path to the go.mod of the main module,
+// or the empty string if not using modules.
+//
+func goMod() (string, error) {
+ out, err := exec.Command("go", "env", "-json", "GOMOD").Output()
+ if ee := (*exec.ExitError)(nil); xerrors.As(err, &ee) {
+ return "", fmt.Errorf("go command exited unsuccessfully: %v\n%s", ee.ProcessState.String(), ee.Stderr)
+ } else if err != nil {
+ return "", err
+ }
+ var env struct {
+ GoMod string
+ }
+ err = json.Unmarshal(out, &env)
+ if err != nil {
+ return "", err
+ }
+ return env.GoMod, nil
+}
+
+// fillModuleCache does a best-effort attempt to fill the module cache
+// with all dependencies of the main module in the current directory
+// by invoking the go command. Module download logs are streamed to w.
+// If there are any problems encountered, they are also written to w.
+// It should only be used in module mode, when vendor mode isn't on.
+//
+// See https://golang.org/cmd/go/#hdr-Download_modules_to_local_cache.
+func fillModuleCache(w io.Writer, goMod string) {
+ if goMod == os.DevNull {
+ // No module requirements, nothing to do.
+ return
+ }
+
+ cmd := exec.Command("go", "mod", "download", "-json")
+ var out bytes.Buffer
+ cmd.Stdout = &out
+ cmd.Stderr = w
+ err := cmd.Run()
+ if ee := (*exec.ExitError)(nil); xerrors.As(err, &ee) && ee.ExitCode() == 1 {
+ // Exit code 1 from this command means there were some
+ // non-empty Error values in the output. Print them to w.
+ fmt.Fprintf(w, "documentation for some packages is not shown:\n")
+ for dec := json.NewDecoder(&out); ; {
+ var m struct {
+ Path string // Module path.
+ Version string // Module version.
+ Error string // Error loading module.
+ }
+ err := dec.Decode(&m)
+ if err == io.EOF {
+ break
+ } else if err != nil {
+ fmt.Fprintf(w, "error decoding JSON object from go mod download -json: %v\n", err)
+ continue
+ }
+ if m.Error == "" {
+ continue
+ }
+ fmt.Fprintf(w, "\tmodule %s@%s is not in the module cache and there was a problem downloading it: %s\n", m.Path, m.Version, m.Error)
+ }
+ } else if err != nil {
+ fmt.Fprintf(w, "there was a problem filling module cache: %v\n", err)
+ }
+}
+
+type mod struct {
+ Path string // Module path.
+ Dir string // Directory holding files for this module, if any.
+}
+
+// buildList determines the build list in the current directory
+// by invoking the go command. It should only be used in module mode,
+// when vendor mode isn't on.
+//
+// See https://golang.org/cmd/go/#hdr-The_main_module_and_the_build_list.
+func buildList(goMod string) ([]mod, error) {
+ if goMod == os.DevNull {
+ // Empty build list.
+ return nil, nil
+ }
+
+ out, err := exec.Command("go", "list", "-m", "-json", "all").Output()
+ if ee := (*exec.ExitError)(nil); xerrors.As(err, &ee) {
+ return nil, fmt.Errorf("go command exited unsuccessfully: %v\n%s", ee.ProcessState.String(), ee.Stderr)
+ } else if err != nil {
+ return nil, err
+ }
+ var mods []mod
+ for dec := json.NewDecoder(bytes.NewReader(out)); ; {
+ var m mod
+ err := dec.Decode(&m)
+ if err == io.EOF {
+ break
+ } else if err != nil {
+ return nil, err
+ }
+ mods = append(mods, m)
+ }
+ return mods, nil
+}
+
+// moduleFS is a vfs.FileSystem wrapper used when godoc is running
+// in module mode. It's needed so that packages inside modules are
+// considered to be third party.
+//
+// It overrides the RootType method of the underlying filesystem
+// and implements it using a heuristic based on the import path.
+// If the first element of the import path does not contain a dot,
+// that package is considered to be inside GOROOT. If it contains
+// a dot, then that package is considered to be third party.
+//
+// TODO(dmitshur): The RootType abstraction works well when GOPATH
+// workspaces are bound at their roots, but scales poorly in the
+// general case. It should be replaced by a more direct solution
+// for determining whether a package is third party or not.
+//
+type moduleFS struct{ vfs.FileSystem }
+
+func (moduleFS) RootType(path string) vfs.RootType {
+ if !strings.HasPrefix(path, "/src/") {
+ return ""
+ }
+ domain := path[len("/src/"):]
+ if i := strings.Index(domain, "/"); i >= 0 {
+ domain = domain[:i]
+ }
+ if !strings.Contains(domain, ".") {
+ // No dot in the first element of import path
+ // suggests this is a package in GOROOT.
+ return vfs.RootTypeGoRoot
+ } else {
+ // A dot in the first element of import path
+ // suggests this is a third party package.
+ return vfs.RootTypeGoPath
+ }
+}
+func (fs moduleFS) String() string { return "module(" + fs.FileSystem.String() + ")" }