cmd/present: use embed, drop native client

Now that x/tools assumes a new enough Go release,
use //go:embed to avoid having to assume the cmd/present
source code is available when running the binary.
Leave App Engine deployment alone for now.

Also delete Native Client code since Go does not support
Native Client anymore.

Change-Id: Ib4da006ca6291d2f9d078353f52cb5a4dc62b19d
Reviewed-on: https://go-review.googlesource.com/c/tools/+/468355
Reviewed-by: Tim King <[email protected]>
Run-TryBot: Russ Cox <[email protected]>
gopls-CI: kokoro <[email protected]>
Reviewed-by: Bryan Mills <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>

Author: rsc

cmd/present/dir.go

@@ -7,6 +7,7 @@ package main
 import (
 	"html/template"
 	"io"
+	"io/fs"
 	"log"
 	"net"
 	"net/http"
@@ -65,29 +66,29 @@ var (
 	contentTemplate map[string]*template.Template
 )
 
-func initTemplates(base string) error {
+func initTemplates(fsys fs.FS) error {
 	// Locate the template file.
-	actionTmpl := filepath.Join(base, "templates/action.tmpl")
+	actionTmpl := "templates/action.tmpl"
 
 	contentTemplate = make(map[string]*template.Template)
 
 	for ext, contentTmpl := range map[string]string{
 		".slide":   "slides.tmpl",
 		".article": "article.tmpl",
 	} {
-		contentTmpl = filepath.Join(base, "templates", contentTmpl)
+		contentTmpl = "templates/" + contentTmpl
 
 		// Read and parse the input.
 		tmpl := present.Template()
 		tmpl = tmpl.Funcs(template.FuncMap{"playable": playable})
-		if _, err := tmpl.ParseFiles(actionTmpl, contentTmpl); err != nil {
+		if _, err := tmpl.ParseFS(fsys, actionTmpl, contentTmpl); err != nil {
 			return err
 		}
 		contentTemplate[ext] = tmpl
 	}
 
 	var err error
-	dirListTemplate, err = template.ParseFiles(filepath.Join(base, "templates/dir.tmpl"))
+	dirListTemplate, err = template.ParseFS(fsys, "templates/dir.tmpl")
 	return err
 }
 

cmd/present/main.go

@@ -5,9 +5,10 @@
 package main
 
 import (
+	"embed"
 	"flag"
 	"fmt"
-	"go/build"
+	"io/fs"
 	"log"
 	"net"
 	"net/http"
@@ -18,17 +19,17 @@ import (
 	"golang.org/x/tools/present"
 )
 
-const basePkg = "golang.org/x/tools/cmd/present"
-
 var (
 	httpAddr      = flag.String("http", "127.0.0.1:3999", "HTTP service address (e.g., '127.0.0.1:3999')")
 	originHost    = flag.String("orighost", "", "host component of web origin URL (e.g., 'localhost')")
 	basePath      = flag.String("base", "", "base path for slide template and static resources")
 	contentPath   = flag.String("content", ".", "base path for presentation content")
 	usePlayground = flag.Bool("use_playground", false, "run code snippets using play.golang.org; if false, run them locally and deliver results by WebSocket transport")
-	nativeClient  = flag.Bool("nacl", false, "use Native Client environment playground (prevents non-Go code execution) when using local WebSocket transport")
 )
 
+//go:embed static templates
+var embedFS embed.FS
+
 func main() {
 	flag.BoolVar(&present.PlayEnabled, "play", true, "enable playground (permit execution of arbitrary user code)")
 	flag.BoolVar(&present.NotesEnabled, "notes", false, "enable presenter notes (press 'N' from the browser to display them)")
@@ -50,16 +51,11 @@ func main() {
 		*contentPath = "./content/"
 	}
 
-	if *basePath == "" {
-		p, err := build.Default.Import(basePkg, "", build.FindOnly)
-		if err != nil {
-			fmt.Fprintf(os.Stderr, "Couldn't find gopresent files: %v\n", err)
-			fmt.Fprintf(os.Stderr, basePathMessage, basePkg)
-			os.Exit(1)
-		}
-		*basePath = p.Dir
+	var fsys fs.FS = embedFS
+	if *basePath != "" {
+		fsys = os.DirFS(*basePath)
 	}
-	err := initTemplates(*basePath)
+	err := initTemplates(fsys)
 	if err != nil {
 		log.Fatalf("Failed to parse templates: %v", err)
 	}
@@ -98,11 +94,11 @@ func main() {
 		}
 	}
 
-	initPlayground(*basePath, origin)
-	http.Handle("/static/", http.FileServer(http.Dir(*basePath)))
+	initPlayground(fsys, origin)
+	http.Handle("/static/", http.FileServer(http.FS(fsys)))
 
 	if !ln.Addr().(*net.TCPAddr).IP.IsLoopback() &&
-		present.PlayEnabled && !*nativeClient && !*usePlayground {
+		present.PlayEnabled && !*usePlayground {
 		log.Print(localhostWarning)
 	}
 

cmd/present/play.go

@@ -7,11 +7,9 @@ package main
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
+	"io/fs"
 	"net/http"
 	"net/url"
-	"path/filepath"
-	"runtime"
 	"time"
 
 	"golang.org/x/tools/godoc/static"
@@ -31,15 +29,15 @@ var scripts = []string{"jquery.js", "jquery-ui.js", "playground.js", "play.js"}
 // playScript registers an HTTP handler at /play.js that serves all the
 // scripts specified by the variable above, and appends a line that
 // initializes the playground with the specified transport.
-func playScript(root, transport string) {
+func playScript(fsys fs.FS, transport string) {
 	modTime := time.Now()
 	var buf bytes.Buffer
 	for _, p := range scripts {
 		if s, ok := static.Files[p]; ok {
 			buf.WriteString(s)
 			continue
 		}
-		b, err := ioutil.ReadFile(filepath.Join(root, "static", p))
+		b, err := fs.ReadFile(fsys, "static/"+p)
 		if err != nil {
 			panic(err)
 		}
@@ -53,27 +51,16 @@ func playScript(root, transport string) {
 	})
 }
 
-func initPlayground(basepath string, origin *url.URL) {
+func initPlayground(fsys fs.FS, origin *url.URL) {
 	if !present.PlayEnabled {
 		return
 	}
 	if *usePlayground {
-		playScript(basepath, "HTTPTransport")
+		playScript(fsys, "HTTPTransport")
 		return
 	}
 
-	if *nativeClient {
-		// When specifying nativeClient, non-Go code cannot be executed
-		// because the NaCl setup doesn't support doing so.
-		socket.RunScripts = false
-		socket.Environ = func() []string {
-			if runtime.GOARCH == "amd64" {
-				return environ("GOOS=nacl", "GOARCH=amd64p32")
-			}
-			return environ("GOOS=nacl")
-		}
-	}
-	playScript(basepath, "SocketTransport")
+	playScript(fsys, "SocketTransport")
 	http.Handle("/socket", socket.NewHandler(origin))
 }