playground: recognize managed vm's as being "on app engine"

Change-Id: I117b113e2782cab1180e6f56e1869525564ab18f
Reviewed-on: https://go-review.googlesource.com/14663
Reviewed-by: Andrew Gerrand <adg@golang.org>

cmd/present/appengine.go

@@ -14,17 +14,11 @@ import (
 	_ "golang.org/x/tools/playground"
 )
 
-var basePath = "./present/"
-
 func init() {
-	initTemplates(basePath)
-	playScript(basePath, "HTTPTransport")
+	initTemplates("./present/")
 	present.PlayEnabled = true
+	initPlayground("./present/", nil)
 
 	// App Engine has no /etc/mime.types
 	mime.AddExtensionType(".svg", "image/svg+xml")
 }
-
-func playable(c present.Code) bool {
-	return present.PlayEnabled && c.Play && c.Ext == ".go"
-}

cmd/present/local.go

@@ -15,35 +15,34 @@ import (
 	"net/http"
 	"net/url"
 	"os"
-	"runtime"
 	"strings"
 
-	"golang.org/x/tools/playground/socket"
 	"golang.org/x/tools/present"
 )
 
 const basePkg = "golang.org/x/tools/cmd/present"
 
-var basePath string
+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")
+	nativeClient = flag.Bool("nacl", false, "use Native Client environment playground (prevents non-Go code execution)")
+)
 
 func main() {
-	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')")
-	flag.StringVar(&basePath, "base", "", "base path for slide template and static resources")
 	flag.BoolVar(&present.PlayEnabled, "play", true, "enable playground (permit execution of arbitrary user code)")
-	nativeClient := flag.Bool("nacl", false, "use Native Client environment playground (prevents non-Go code execution)")
 	flag.Parse()
 
-	if basePath == "" {
+	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
+		*basePath = p.Dir
 	}
-	err := initTemplates(basePath)
+	err := initTemplates(*basePath)
 	if err != nil {
 		log.Fatalf("Failed to parse templates: %v", err)
 	}
@@ -58,6 +57,7 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
+
 	origin := &url.URL{Scheme: "http"}
 	if *originHost != "" {
 		origin.Host = net.JoinHostPort(*originHost, port)
@@ -76,20 +76,8 @@ func main() {
 		}
 	}
 
-	if present.PlayEnabled {
-		if *nativeClient {
-			socket.RunScripts = false
-			socket.Environ = func() []string {
-				if runtime.GOARCH == "amd64" {
-					return environ("GOOS=nacl", "GOARCH=amd64p32")
-				}
-				return environ("GOOS=nacl")
-			}
-		}
-		playScript(basePath, "SocketTransport")
-		http.Handle("/socket", socket.NewHandler(origin))
-	}
-	http.Handle("/static/", http.FileServer(http.Dir(basePath)))
+	initPlayground(*basePath, origin)
+	http.Handle("/static/", http.FileServer(http.Dir(*basePath)))
 
 	if !ln.Addr().(*net.TCPAddr).IP.IsLoopback() &&
 		present.PlayEnabled && !*nativeClient {
@@ -100,10 +88,6 @@ func main() {
 	log.Fatal(http.Serve(ln, nil))
 }
 
-func playable(c present.Code) bool {
-	return present.PlayEnabled && c.Play
-}
-
 func environ(vars ...string) []string {
 	env := os.Environ()
 	for _, r := range vars {

cmd/present/play_http.go

@@ -0,0 +1,21 @@
+// Copyright 2015 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.
+
+// +build appengine appenginevm
+
+package main
+
+import (
+	"net/url"
+
+	"golang.org/x/tools/present"
+)
+
+func initPlayground(basepath string, origin *url.URL) {
+	playScript(basepath, "HTTPTransport")
+}
+
+func playable(c present.Code) bool {
+	return present.PlayEnabled && c.Play && c.Ext == ".go"
+}

cmd/present/play_socket.go

@@ -0,0 +1,36 @@
+// Copyright 2015 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.
+
+// +build !appengine,!appenginevm
+
+package main
+
+import (
+	"net/http"
+	"net/url"
+	"runtime"
+
+	"golang.org/x/tools/playground/socket"
+	"golang.org/x/tools/present"
+)
+
+func initPlayground(basepath string, origin *url.URL) {
+	if present.PlayEnabled {
+		if *nativeClient {
+			socket.RunScripts = false
+			socket.Environ = func() []string {
+				if runtime.GOARCH == "amd64" {
+					return environ("GOOS=nacl", "GOARCH=amd64p32")
+				}
+				return environ("GOOS=nacl")
+			}
+		}
+		playScript(basepath, "SocketTransport")
+		http.Handle("/socket", socket.NewHandler(origin))
+	}
+}
+
+func playable(c present.Code) bool {
+	return present.PlayEnabled && c.Play
+}

playground/appenginevm.go

@@ -0,0 +1,11 @@
+// Copyright 2015 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.
+
+// +build appenginevm
+
+package playground
+
+func init() {
+	onAppengine = true
+}

playground/common.go

@@ -49,7 +49,7 @@ func passThru(w io.Writer, req *http.Request) error {
 	return nil
 }
 
-var onAppengine = false // will be overriden by appengine.go
+var onAppengine = false // will be overriden by appengine.go and appenginevm.go
 
 func allowShare(r *http.Request) bool {
 	if !onAppengine {