cmd/gio: add buildmode=exe for building gio programs ready to run

And add Android implementation.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

cmd/gio/androidbuild.go

@@ -0,0 +1,538 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package main
+
+import (
+	"archive/zip"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path"
+	"path/filepath"
+	"runtime"
+	"strconv"
+	"strings"
+
+	"golang.org/x/sync/errgroup"
+)
+
+type androidTools struct {
+	buildtools string
+	androidjar string
+}
+
+// zip.Writer with a sticky error.
+type zipWriter struct {
+	err error
+	w   *zip.Writer
+}
+
+// Writer that saves any errors.
+type errWriter struct {
+	w   io.Writer
+	err *error
+}
+
+func buildAndroid(tmpDir string, bi *buildInfo) error {
+	sdk := os.Getenv("ANDROID_HOME")
+	if sdk == "" {
+		return errors.New("Please set ANDROID_HOME to the Android SDK path")
+	}
+	if _, err := os.Stat(sdk); err != nil {
+		return err
+	}
+	platform, err := latestPlatform(sdk)
+	if err != nil {
+		return err
+	}
+	buildtools, err := latestTools(sdk)
+	if err != nil {
+		return err
+	}
+
+	tools := &androidTools{
+		buildtools: buildtools,
+		androidjar: filepath.Join(platform, "android.jar"),
+	}
+	if err := compileAndroid(tmpDir, tools, bi); err != nil {
+		return err
+	}
+	switch *buildMode {
+	case "archive":
+		return archiveAndroid(tmpDir, bi)
+	case "exe":
+		if err := exeAndroid(tmpDir, tools, bi); err != nil {
+			return err
+		}
+		return signAPK(tmpDir, tools, bi)
+	default:
+		panic("unreachable")
+	}
+}
+
+func compileAndroid(tmpDir string, tools *androidTools, bi *buildInfo) (err error) {
+	androidHome := os.Getenv("ANDROID_HOME")
+	if androidHome == "" {
+		return errors.New("ANDROID_HOME is not set. Please point it to the root of the Android SDK.")
+	}
+	ndkRoot := filepath.Join(androidHome, "ndk-bundle")
+	if _, err := os.Stat(ndkRoot); err != nil {
+		return fmt.Errorf("No NDK found in $ANDROID_HOME/ndk-bundle (%s). Use `sdkmanager ndk-bundle` to install it.", ndkRoot)
+	}
+	tcRoot := filepath.Join(ndkRoot, "toolchains", "llvm", "prebuilt", archNDK())
+	var builds errgroup.Group
+	for _, a := range bi.archs {
+		arch := allArchs[a]
+		clang := filepath.Join(tcRoot, "bin", arch.clang)
+		if _, err := os.Stat(clang); err != nil {
+			return fmt.Errorf("No NDK compiler found. Please make sure you have NDK >= r19c installed. Use the command `sdkmanager ndk-bundle` to install it. Path %s", clang)
+		}
+		if runtime.GOOS == "windows" {
+			// Because of https://github.com/android-ndk/ndk/issues/920,
+			// we need NDK r19c, not just r19b. Check for the presence of
+			// clang++.cmd which is only available in r19c.
+			clangpp := filepath.Join(tcRoot, "bin", arch.clang+"++.cmd")
+			if _, err := os.Stat(clangpp); err != nil {
+				return fmt.Errorf("NDK version r19b detected, but >= r19c is required. Use the command `sdkmanager ndk-bundle` to install it.")
+			}
+		}
+		archDir := filepath.Join(tmpDir, "jni", arch.jniArch)
+		if err := os.MkdirAll(archDir, 0755); err != nil {
+			return fmt.Errorf("failed to create %q: %v", archDir, err)
+		}
+		libFile := filepath.Join(archDir, "libgio.so")
+		cmd := exec.Command(
+			"go",
+			"build",
+			"-ldflags=-w -s "+bi.ldflags,
+			"-buildmode=c-shared",
+			"-o", libFile,
+			bi.pkg,
+		)
+		cmd.Env = append(
+			os.Environ(),
+			"GOOS=android",
+			"GOARCH="+a,
+			"CGO_ENABLED=1",
+			"CC="+clang,
+			"CGO_CFLAGS=-Werror",
+		)
+		builds.Go(func() error {
+			_, err := runCmd(cmd)
+			return err
+		})
+	}
+	appDir, err := appDir()
+	if err != nil {
+		return err
+	}
+	javaFiles, err := filepath.Glob(filepath.Join(appDir, "*.java"))
+	if err != nil {
+		return err
+	}
+	if len(javaFiles) > 0 {
+		classes := filepath.Join(tmpDir, "classes")
+		if err := os.MkdirAll(classes, 0755); err != nil {
+			return err
+		}
+		javac := exec.Command(
+			"javac",
+			"-target", "1.8",
+			"-source", "1.8",
+			"-sourcepath", appDir,
+			"-bootclasspath", tools.androidjar,
+			"-d", classes,
+		)
+		javac.Args = append(javac.Args, javaFiles...)
+		builds.Go(func() error {
+			_, err := runCmd(javac)
+			return err
+		})
+	}
+	return builds.Wait()
+}
+
+func archiveAndroid(tmpDir string, bi *buildInfo) (err error) {
+	aarFile := *destPath
+	if aarFile == "" {
+		aarFile = fmt.Sprintf("%s.aar", filepath.Base(bi.pkg))
+	}
+	if filepath.Ext(aarFile) != ".aar" {
+		return fmt.Errorf("the specified output %q does not end in '.aar'", aarFile)
+	}
+	aar, err := os.Create(aarFile)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if cerr := aar.Close(); err == nil {
+			err = cerr
+		}
+	}()
+	aarw := newZipWriter(aar)
+	defer aarw.Close()
+	aarw.Create("R.txt")
+	aarw.Create("res/")
+	manifest := aarw.Create("AndroidManifest.xml")
+	manifest.Write([]byte(`<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="org.gioui.app">
+	<uses-sdk android:minSdkVersion="16"/>
+	<uses-feature android:glEsVersion="0x00030000" android:required="true" />
+</manifest>`))
+	proguard := aarw.Create("proguard.txt")
+	proguard.Write([]byte(`-keep class org.gioui.** { *; }`))
+
+	for _, a := range bi.archs {
+		arch := allArchs[a]
+		libFile := filepath.Join("jni", arch.jniArch, "libgio.so")
+		aarw.Add(filepath.ToSlash(libFile), filepath.Join(tmpDir, libFile))
+	}
+	classes := filepath.Join(tmpDir, "classes")
+	if _, err := os.Stat(classes); err == nil {
+		jarFile := filepath.Join(tmpDir, "classes.jar")
+		if err := writeJar(jarFile, classes); err != nil {
+			return err
+		}
+		aarw.Add("classes.jar", jarFile)
+	}
+	return aarw.Close()
+}
+
+func exeAndroid(tmpDir string, tools *androidTools, bi *buildInfo) (err error) {
+	if *appID == "" {
+		return errors.New("app id is empty; use -appid to set it")
+	}
+	classes := filepath.Join(tmpDir, "classes")
+	var classFiles []string
+	err = filepath.Walk(classes, func(path string, f os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if filepath.Ext(path) == ".class" {
+			classFiles = append(classFiles, path)
+		}
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+	apkDir := filepath.Join(tmpDir, "apk")
+	if err := os.MkdirAll(apkDir, 0755); err != nil {
+		return err
+	}
+	if len(classFiles) > 0 {
+		d8 := exec.Command(
+			filepath.Join(tools.buildtools, "d8"),
+			"--classpath", tools.androidjar,
+			"--output", apkDir,
+		)
+		d8.Args = append(d8.Args, classFiles...)
+		if _, err := runCmd(d8); err != nil {
+			return err
+		}
+	}
+	manifestSrc := fmt.Sprintf(`<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+	package="%s"
+	android:versionCode="1"
+	android:versionName="1.0">
+	<uses-sdk android:minSdkVersion="16" android:targetSdkVersion="28" />
+	<uses-permission android:name="android.permission.INTERNET" />
+	<uses-feature android:glEsVersion="0x00030000"/>
+	<application android:label="Gio">
+		<activity android:name="org.gioui.GioActivity"
+			android:label="Gio"
+			android:theme="@android:style/Theme.NoTitleBar"
+			android:configChanges="orientation|keyboardHidden">
+			<intent-filter>
+				<action android:name="android.intent.action.MAIN" />
+				<category android:name="android.intent.category.LAUNCHER" />
+			</intent-filter>
+		</activity>
+	</application>
+</manifest>`, *appID)
+	manifest := filepath.Join(tmpDir, "AndroidManifest.xml")
+	if err := ioutil.WriteFile(manifest, []byte(manifestSrc), 0600); err != nil {
+		return err
+	}
+	tmpapk := filepath.Join(tmpDir, "link.apk")
+	_, err = runCmd(exec.Command(
+		filepath.Join(tools.buildtools, "aapt2"),
+		"link",
+		"--manifest", manifest,
+		"-I", tools.androidjar,
+		"-o", tmpapk,
+	))
+	if err != nil {
+		return err
+	}
+	// The Go standard library archive/zip doesn't support appending to zip
+	// files. Unpack the apk from aapt2 and re-zip its contents along with
+	// classes.dex and the Go libraries.
+	if err := unzip(apkDir, tmpapk); err != nil {
+		return err
+	}
+	tmpApk := filepath.Join(tmpDir, "app.ap_")
+	ap_, err := os.Create(tmpApk)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if cerr := ap_.Close(); err == nil {
+			err = cerr
+		}
+	}()
+	apkw := newZipWriter(ap_)
+	defer apkw.Close()
+	apkFiles, err := filepath.Glob(filepath.Join(apkDir, "*"))
+	if err != nil {
+		return err
+	}
+	for _, f := range apkFiles {
+		name := filepath.Base(f)
+		apkw.Add(name, f)
+	}
+	for _, a := range bi.archs {
+		arch := allArchs[a]
+		libFile := filepath.Join(arch.jniArch, "libgio.so")
+		apkw.Add(filepath.ToSlash(filepath.Join("lib", libFile)), filepath.Join(tmpDir, "jni", libFile))
+	}
+	return apkw.Close()
+}
+
+func signAPK(tmpDir string, tools *androidTools, bi *buildInfo) error {
+	apkFile := *destPath
+	if apkFile == "" {
+		apkFile = fmt.Sprintf("%s.apk", filepath.Base(bi.pkg))
+	}
+	if filepath.Ext(apkFile) != ".apk" {
+		return fmt.Errorf("the specified output %q does not end in '.apk'", apkFile)
+	}
+	_, err := runCmd(exec.Command(
+		filepath.Join(tools.buildtools, "zipalign"),
+		"-f",
+		"4", // 32-bit alignment.
+		filepath.Join(tmpDir, "app.ap_"),
+		apkFile,
+	))
+	if err != nil {
+		return err
+	}
+	home, err := os.UserHomeDir()
+	if err != nil {
+		return err
+	}
+	keystore := filepath.Join(home, ".android", "debug.keystore")
+	if _, err := os.Stat(keystore); err == nil {
+		_, err = runCmd(exec.Command(
+			filepath.Join(tools.buildtools, "apksigner"),
+			"sign",
+			"--ks-pass", "pass:android",
+			"--ks", keystore,
+			apkFile,
+		))
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func unzip(dir, zipfile string) (err error) {
+	zipr, err := zip.OpenReader(zipfile)
+	if err != nil {
+		return err
+	}
+	defer zipr.Close()
+	for _, f := range zipr.File {
+		path := filepath.Join(dir, path.Base(f.Name))
+		out, err := os.Create(path)
+		if err != nil {
+			return err
+		}
+		defer func() {
+			if cerr := out.Close(); err == nil {
+				err = cerr
+			}
+		}()
+		in, err := f.Open()
+		if err != nil {
+			return err
+		}
+		defer in.Close()
+		if _, err := io.Copy(out, in); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func writeJar(jarFile, dir string) (err error) {
+	jar, err := os.Create(jarFile)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if cerr := jar.Close(); err == nil {
+			err = cerr
+		}
+	}()
+	jarw := newZipWriter(jar)
+	const manifestHeader = `Manifest-Version: 1.0
+Created-By: 1.0 (Go)
+
+`
+	jarw.Create("META-INF/MANIFEST.MF").Write([]byte(manifestHeader))
+	err = filepath.Walk(dir, func(path string, f os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if f.IsDir() {
+			return nil
+		}
+		if filepath.Ext(path) == ".class" {
+			rel := filepath.ToSlash(path[len(dir)+1:])
+			jarw.Add(rel, path)
+		}
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+	return jarw.Close()
+}
+
+func archNDK() string {
+	if runtime.GOOS == "windows" && runtime.GOARCH == "386" {
+		return "windows"
+	} else {
+		var arch string
+		switch runtime.GOARCH {
+		case "386":
+			arch = "x86"
+		case "amd64":
+			arch = "x86_64"
+		default:
+			panic("unsupported GOARCH: " + runtime.GOARCH)
+		}
+		return runtime.GOOS + "-" + arch
+	}
+}
+
+func latestPlatform(sdk string) (string, error) {
+	allPlats, err := filepath.Glob(filepath.Join(sdk, "platforms", "android-*"))
+	if err != nil {
+		return "", err
+	}
+	var bestVer int
+	var bestPlat string
+	for _, platform := range allPlats {
+		_, name := filepath.Split(platform)
+		// The glob above guarantees the "android-" prefix.
+		verStr := name[len("android-"):]
+		ver, err := strconv.Atoi(verStr)
+		if err != nil {
+			continue
+		}
+		if ver < bestVer {
+			continue
+		}
+		bestVer = ver
+		bestPlat = platform
+	}
+	if bestPlat == "" {
+		return "", fmt.Errorf("no platforms found in %q", sdk)
+	}
+	return bestPlat, nil
+}
+
+func latestTools(sdk string) (string, error) {
+	allTools, err := filepath.Glob(filepath.Join(sdk, "build-tools", "*"))
+	if err != nil {
+		return "", err
+	}
+	var bestVer [3]int
+	var bestTools string
+loop:
+	for _, tools := range allTools {
+		_, name := filepath.Split(tools)
+		s := strings.SplitN(name, ".", 3)
+		if len(s) != len(bestVer) {
+			continue
+		}
+		var version [3]int
+		for i, v := range s {
+			v, err := strconv.Atoi(v)
+			if err != nil {
+				continue loop
+			}
+			if v < bestVer[i] {
+				continue loop
+			}
+			if v > bestVer[i] {
+				break
+			}
+			version[i] = v
+		}
+		bestVer = version
+		bestTools = tools
+	}
+	if bestTools == "" {
+		return "", fmt.Errorf("no build-tools found in %q", sdk)
+	}
+	return bestTools, nil
+}
+
+func newZipWriter(w io.Writer) *zipWriter {
+	return &zipWriter{
+		w: zip.NewWriter(w),
+	}
+}
+
+func (z *zipWriter) Close() error {
+	err := z.w.Close()
+	if z.err == nil {
+		z.err = err
+	}
+	return z.err
+}
+
+func (z *zipWriter) Create(name string) io.Writer {
+	if z.err != nil {
+		return ioutil.Discard
+	}
+	w, err := z.w.Create(name)
+	if err != nil {
+		z.err = err
+		return ioutil.Discard
+	}
+	return &errWriter{w: w, err: &z.err}
+}
+
+func (z *zipWriter) Add(name, file string) {
+	if z.err != nil {
+		return
+	}
+	w := z.Create(name)
+	f, err := os.Open(file)
+	if err != nil {
+		z.err = err
+		return
+	}
+	defer f.Close()
+	if _, err := io.Copy(w, f); err != nil {
+		z.err = err
+		return
+	}
+}
+
+func (w *errWriter) Write(p []byte) (n int, err error) {
+	if err := *w.err; err != nil {
+		return 0, err
+	}
+	n, err = w.w.Write(p)
+	*w.err = err
+	return
+}

cmd/gio/gio.go

@@ -3,9 +3,7 @@
 package main
 
 import (
-	"archive/zip"
 	"bytes"
-	"errors"
 	"flag"
 	"fmt"
 	"io"
@@ -13,32 +11,25 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
-	"runtime"
-	"strconv"
 	"strings"
 
 	"golang.org/x/sync/errgroup"
 )
 
-// zip.Writer with a sticky error.
-type zipWriter struct {
-	err error
-	w   *zip.Writer
-}
-
-// Writer that saves any errors.
-type errWriter struct {
-	w   io.Writer
-	err *error
-}
-
 var (
 	target    = flag.String("target", "", "specify target (ios, tvos, android)")
 	archNames = flag.String("arch", "", "specify architecture(s) to include")
-	destPath  = flag.String("o", "", "output file (for Android .aar) or directory (for iOS/tvOS .framework)")
+	buildMode = flag.String("buildmode", "archive", "specify buildmode: archive or exe")
+	destPath  = flag.String("o", "", "output file (Android .aar or .apk file) or directory (iOS/tvOS .framework)")
 	verbose   = flag.Bool("v", false, "verbose output")
 )
 
+type buildInfo struct {
+	pkg     string
+	ldflags string
+	archs   []string
+}
+
 func main() {
 	flag.Usage = func() {
 		fmt.Fprintf(os.Stderr, "Gio is a tool for building and running gio programs.\n\n")
@@ -56,6 +47,16 @@ func main() {
 		flag.PrintDefaults()
 		os.Exit(2)
 	}
+	switch *target {
+	case "ios", "tvos", "android":
+	default:
+		errorf("invalid -target %s\n", *target)
+	}
+	switch *buildMode {
+	case "archive", "exe":
+	default:
+		errorf("invalid -buildmode %s\n", *buildMode)
+	}
 	// Expand relative package paths.
 	out, err := exec.Command("go", "list", pkg).Output()
 	if err != nil {
@@ -64,49 +65,48 @@ func main() {
 		}
 		errorf("gio: failed to run the go tool: %v", err)
 	}
-	pkg = string(bytes.TrimSpace(out))
+	bi := &buildInfo{
-	appArgs := flag.Args()[1:]
+		pkg: string(bytes.TrimSpace(out)),
-	if err := run(pkg, appArgs); err != nil {
+	}
+	switch *target {
+	case "ios", "tvos":
+		// Only 64-bit support.
+		bi.archs = []string{"arm64", "amd64"}
+	case "android":
+		bi.archs = []string{"arm", "arm64", "386", "amd64"}
+	}
+	if *archNames != "" {
+		bi.archs = strings.Split(*archNames, ",")
+	}
+	if appArgs := flag.Args()[1:]; len(appArgs) > 0 {
+		// Pass along arguments to the app.
+		bi.ldflags = fmt.Sprintf("-X gioui.org/ui/app.extraArgs=%s", strings.Join(appArgs, "|"))
+	}
+	if err := build(bi); err != nil {
 		errorf("gio: %v", err)
 	}
 }
 
-func run(pkg string, appArgs []string) error {
+func build(bi *buildInfo) error {
 	tmpDir, err := ioutil.TempDir("", "gio-")
 	if err != nil {
 		return err
 	}
 	defer os.RemoveAll(tmpDir)
-	var ldflags string
-	if len(appArgs) > 0 {
-		// Pass along arguments to the app.
-		ldflags = fmt.Sprintf("-X gioui.org/ui/app.extraArgs=%s", strings.Join(appArgs, "|"))
-	}
-	var archs []string
 	switch *target {
 	case "ios", "tvos":
-		// Only 64-bit support.
+		return archiveIOS(tmpDir, *target, bi)
-		archs = []string{"arm64", "amd64"}
 	case "android":
-		archs = []string{"arm", "arm64", "386", "amd64"}
+		return buildAndroid(tmpDir, bi)
-	}
-	if *archNames != "" {
-		archs = strings.Split(*archNames, ",")
-	}
-	switch *target {
-	case "ios", "tvos":
-		return runIOS(tmpDir, *target, pkg, archs, ldflags)
-	case "android":
-		return runAndroid(tmpDir, pkg, archs, ldflags)
 	default:
-		return fmt.Errorf("invalid -target %s\n", *target)
+		panic("unreachable")
 	}
 }
 
-func runIOS(tmpDir, target, pkg string, archs []string, ldflags string) error {
+func archiveIOS(tmpDir, target string, bi *buildInfo) error {
 	frameworkRoot := *destPath
 	if frameworkRoot == "" {
-		appName := filepath.Base(pkg)
+		appName := filepath.Base(bi.pkg)
 		frameworkRoot = fmt.Sprintf("%s.framework", strings.Title(appName))
 	}
 	framework := filepath.Base(frameworkRoot)
@@ -139,7 +139,7 @@ func runIOS(tmpDir, target, pkg string, archs []string, ldflags string) error {
 	exe := filepath.Join(frameworkDir, framework)
 	lipo := exec.Command("xcrun", "lipo", "-o", exe, "-create")
 	var builds errgroup.Group
-	for _, a := range archs {
+	for _, a := range bi.archs {
 		arch := allArchs[a]
 		var platformSDK string
 		var platformOS string
@@ -175,11 +175,11 @@ func runIOS(tmpDir, target, pkg string, archs []string, ldflags string) error {
 		cmd := exec.Command(
 			"go",
 			"build",
-			"-ldflags=-s -w "+ldflags,
+			"-ldflags=-s -w "+bi.ldflags,
 			"-buildmode=c-archive",
 			"-o", lib,
 			"-tags", "ios",
-			pkg,
+			bi.pkg,
 		)
 		lipo.Args = append(lipo.Args, lib)
 		cmd.Env = append(
@@ -220,192 +220,6 @@ func runIOS(tmpDir, target, pkg string, archs []string, ldflags string) error {
 	return ioutil.WriteFile(moduleFile, []byte(module), 0644)
 }
 
-func runAndroid(tmpDir, pkg string, archs []string, ldflags string) (err error) {
-	androidHome := os.Getenv("ANDROID_HOME")
-	if androidHome == "" {
-		return errors.New("ANDROID_HOME is not set. Please point it to the root of the Android SDK.")
-	}
-	ndkRoot := filepath.Join(androidHome, "ndk-bundle")
-	if _, err := os.Stat(ndkRoot); err != nil {
-		return fmt.Errorf("No NDK found in $ANDROID_HOME/ndk-bundle (%s). Use `sdkmanager ndk-bundle` to install it.", ndkRoot)
-	}
-	tcRoot := filepath.Join(ndkRoot, "toolchains", "llvm", "prebuilt", archNDK())
-	sdk := os.Getenv("ANDROID_HOME")
-	if sdk == "" {
-		return errors.New("Please set ANDROID_HOME to the Android SDK path")
-	}
-	if _, err := os.Stat(sdk); err != nil {
-		return err
-	}
-	platform, err := latestPlatform(sdk)
-	if err != nil {
-		return err
-	}
-	var builds errgroup.Group
-	for _, a := range archs {
-		arch := allArchs[a]
-		clang := filepath.Join(tcRoot, "bin", arch.clang)
-		if _, err := os.Stat(clang); err != nil {
-			return fmt.Errorf("No NDK compiler found. Please make sure you have NDK >= r19c installed. Use the command `sdkmanager ndk-bundle` to install it. Path %s", clang)
-		}
-		if runtime.GOOS == "windows" {
-			// Because of https://github.com/android-ndk/ndk/issues/920,
-			// we need NDK r19c, not just r19b. Check for the presence of
-			// clang++.cmd which is only available in r19c.
-			clangpp := filepath.Join(tcRoot, "bin", arch.clang+"++.cmd")
-			if _, err := os.Stat(clangpp); err != nil {
-				return fmt.Errorf("NDK version r19b detected, but >= r19c is required. Use the command `sdkmanager ndk-bundle` to install it.")
-			}
-		}
-		archDir := filepath.Join(tmpDir, "jni", arch.jniArch)
-		if err := os.MkdirAll(archDir, 0755); err != nil {
-			return fmt.Errorf("failed to create %q: %v", archDir, err)
-		}
-		libFile := filepath.Join(archDir, "libgio.so")
-		cmd := exec.Command(
-			"go",
-			"build",
-			"-ldflags=-w -s "+ldflags,
-			"-buildmode=c-shared",
-			"-o", libFile,
-			pkg,
-		)
-		cmd.Env = append(
-			os.Environ(),
-			"GOOS=android",
-			"GOARCH="+a,
-			"CGO_ENABLED=1",
-			"CC="+clang,
-			"CGO_CFLAGS=-Werror",
-		)
-		builds.Go(func() error {
-			_, err := runCmd(cmd)
-			return err
-		})
-	}
-	if err := builds.Wait(); err != nil {
-		return err
-	}
-	aarFile := *destPath
-	if aarFile == "" {
-		aarFile = fmt.Sprintf("%s.aar", filepath.Base(pkg))
-	}
-	if filepath.Ext(aarFile) != ".aar" {
-		return fmt.Errorf("the specified output %q does not end in '.aar'", aarFile)
-	}
-	aar, err := os.Create(aarFile)
-	if err != nil {
-		return err
-	}
-	defer func() {
-		if cerr := aar.Close(); err == nil {
-			err = cerr
-		}
-	}()
-	aarw := newZipWriter(aar)
-	defer aarw.Close()
-	aarw.Create("R.txt")
-	aarw.Create("res/")
-	manifest := aarw.Create("AndroidManifest.xml")
-	manifest.Write([]byte(`<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="org.gioui.app">
-	<uses-sdk android:minSdkVersion="16"/>
-	<uses-feature android:glEsVersion="0x00030000" android:required="true" />
-</manifest>`))
-	proguard := aarw.Create("proguard.txt")
-	proguard.Write([]byte(`-keep class org.gioui.** { *; }`))
-
-	for _, a := range archs {
-		arch := allArchs[a]
-		libFile := filepath.Join("jni", arch.jniArch, "libgio.so")
-		aarw.Add(filepath.ToSlash(libFile), filepath.Join(tmpDir, libFile))
-	}
-	appDir, err := appDir()
-	if err != nil {
-		return err
-	}
-	javaFiles, err := filepath.Glob(filepath.Join(appDir, "*.java"))
-	if err != nil {
-		return err
-	}
-	if len(javaFiles) > 0 {
-		clsPath := filepath.Join(platform, "android.jar")
-		classes := filepath.Join(tmpDir, "classes")
-		if err := os.MkdirAll(classes, 0755); err != nil {
-			return err
-		}
-		javac := exec.Command(
-			"javac",
-			"-target", "1.8",
-			"-source", "1.8",
-			"-sourcepath", appDir,
-			"-bootclasspath", clsPath,
-			"-d", classes,
-		)
-		javac.Args = append(javac.Args, javaFiles...)
-		if _, err := runCmd(javac); err != nil {
-			return err
-		}
-		jarFile := filepath.Join(tmpDir, "classes.jar")
-		if err := writeJar(jarFile, classes); err != nil {
-			return err
-		}
-		aarw.Add("classes.jar", jarFile)
-	}
-	return aarw.Close()
-}
-
-func newZipWriter(w io.Writer) *zipWriter {
-	return &zipWriter{
-		w: zip.NewWriter(w),
-	}
-}
-
-func (z *zipWriter) Close() error {
-	err := z.w.Close()
-	if z.err == nil {
-		z.err = err
-	}
-	return z.err
-}
-
-func (z *zipWriter) Create(name string) io.Writer {
-	if z.err != nil {
-		return ioutil.Discard
-	}
-	w, err := z.w.Create(name)
-	if err != nil {
-		z.err = err
-		return ioutil.Discard
-	}
-	return &errWriter{w: w, err: &z.err}
-}
-
-func (z *zipWriter) Add(name, file string) {
-	if z.err != nil {
-		return
-	}
-	w := z.Create(name)
-	f, err := os.Open(file)
-	if err != nil {
-		z.err = err
-		return
-	}
-	defer f.Close()
-	if _, err := io.Copy(w, f); err != nil {
-		z.err = err
-		return
-	}
-}
-
-func (w *errWriter) Write(p []byte) (n int, err error) {
-	if err := *w.err; err != nil {
-		return 0, err
-	}
-	n, err = w.w.Write(p)
-	*w.err = err
-	return
-}
-
 func errorf(format string, args ...interface{}) {
 	fmt.Fprintf(os.Stderr, format+"\n", args...)
 	os.Exit(2)
@@ -446,10 +260,6 @@ func copyFile(dst, src string) (err error) {
 
 func appDir() (string, error) {
 	cmd := exec.Command("go", "list", "-f", "{{.Dir}}", "gioui.org/ui/app")
-	cmd.Env = append(
-		os.Environ(),
-		"GOOS=android",
-	)
 	out, err := runCmd(cmd)
 	if err != nil {
 		return "", err
@@ -458,41 +268,6 @@ func appDir() (string, error) {
 	return appDir, nil
 }
 
-func writeJar(jarFile, dir string) (err error) {
-	jar, err := os.Create(jarFile)
-	if err != nil {
-		return err
-	}
-	defer func() {
-		if cerr := jar.Close(); err == nil {
-			err = cerr
-		}
-	}()
-	jarw := newZipWriter(jar)
-	const manifestHeader = `Manifest-Version: 1.0
-Created-By: 1.0 (Go)
-
-`
-	jarw.Create("META-INF/MANIFEST.MF").Write([]byte(manifestHeader))
-	err = filepath.Walk(dir, func(path string, f os.FileInfo, err error) error {
-		if err != nil {
-			return err
-		}
-		if f.IsDir() {
-			return nil
-		}
-		if filepath.Ext(path) == ".class" {
-			rel := filepath.ToSlash(path[len(dir)+1:])
-			jarw.Add(rel, path)
-		}
-		return nil
-	})
-	if err != nil {
-		return err
-	}
-	return jarw.Close()
-}
-
 type arch struct {
 	iosArch string
 	jniArch string
@@ -521,47 +296,3 @@ var allArchs = map[string]arch{
 		clang:   "x86_64-linux-android21-clang",
 	},
 }
-
-func archNDK() string {
-	if runtime.GOOS == "windows" && runtime.GOARCH == "386" {
-		return "windows"
-	} else {
-		var arch string
-		switch runtime.GOARCH {
-		case "386":
-			arch = "x86"
-		case "amd64":
-			arch = "x86_64"
-		default:
-			panic("unsupported GOARCH: " + runtime.GOARCH)
-		}
-		return runtime.GOOS + "-" + arch
-	}
-}
-
-func latestPlatform(sdk string) (string, error) {
-	allPlats, err := filepath.Glob(filepath.Join(sdk, "platforms", "android-*"))
-	if err != nil {
-		return "", err
-	}
-	var bestVer int
-	var bestPlat string
-	for _, platform := range allPlats {
-		_, name := filepath.Split(platform)
-		// The glob above guarantees the "android-" prefix.
-		verStr := name[len("android-"):]
-		ver, err := strconv.Atoi(verStr)
-		if err != nil {
-			continue
-		}
-		if ver < bestVer {
-			continue
-		}
-		bestVer = ver
-		bestPlat = platform
-	}
-	if bestPlat == "" {
-		return "", fmt.Errorf("no platforms found in %q", sdk)
-	}
-	return bestPlat, nil
-}