cmd/gogio: [android] add support for AAB

That patch makes possible to generate Android App Bundle (`.aab`) instead
of APK. In order to generate AAB use `-o outputfile.aab`.

Signed-off-by: Inkeliz <inkeliz@inkeliz.com>

cmd/gogio/androidbuild.go

@@ -153,10 +153,27 @@ func buildAndroid(tmpDir string, bi *buildInfo) error {
 	case "archive":
 		return archiveAndroid(tmpDir, bi, perms)
 	case "exe":
-		if err := exeAndroid(tmpDir, tools, bi, extraJars, perms); err != nil {
+		file := *destPath
+		if file == "" {
+			file = fmt.Sprintf("%s.apk", bi.name)
+		}
+
+		isBundle := false
+		switch filepath.Ext(file) {
+		case ".apk":
+		case ".aab":
+			isBundle = true
+		default:
+			return fmt.Errorf("the specified output %q does not end in '.apk' or '.aab'", file)
+		}
+
+		if err := exeAndroid(tmpDir, tools, bi, extraJars, perms, isBundle); err != nil {
 			return err
 		}
-		return signAPK(tmpDir, tools, bi)
+		if isBundle {
+			return signAAB(tmpDir, file, tools, bi)
+		}
+		return signAPK(tmpDir, file, tools, bi)
 	default:
 		panic("unreachable")
 	}
@@ -316,7 +333,7 @@ func archiveAndroid(tmpDir string, bi *buildInfo, perms []string) (err error) {
 	return aarw.Close()
 }
 
-func exeAndroid(tmpDir string, tools *androidTools, bi *buildInfo, extraJars, perms []string) (err error) {
+func exeAndroid(tmpDir string, tools *androidTools, bi *buildInfo, extraJars, perms []string, isBundle bool) (err error) {
 	classes := filepath.Join(tmpDir, "classes")
 	var classFiles []string
 	err = filepath.Walk(classes, func(path string, f os.FileInfo, err error) error {
@@ -441,20 +458,25 @@ func exeAndroid(tmpDir string, tools *androidTools, bi *buildInfo, extraJars, pe
 	}
 
 	linkAPK := filepath.Join(tmpDir, "link.apk")
-	link := exec.Command(
-		aapt2,
+
+	args := []string{
 		"link",
 		"--manifest", manifest,
 		"-I", tools.androidjar,
 		"-o", linkAPK,
-		resZip,
-	)
-	if _, err := runCmd(link); err != nil {
+	}
+	if isBundle {
+		args = append(args, "--proto-format")
+	}
+	args = append(args, resZip)
+
+	if _, err := runCmd(exec.Command(aapt2, args...)); err != nil {
 		return err
 	}
+
 	// The Go standard library archive/zip doesn't support appending to zip
 	// files. Copy files from `link.apk` (generated by aapt2) along with classes.dex and
-	// the Go libraries to a new `app.ap_` file.
+	// the Go libraries to a new `app.zip` file.
 
 	// Load link.apk as zip.
 	linkAPKZip, err := zip.OpenReader(linkAPK)
@@ -464,7 +486,7 @@ func exeAndroid(tmpDir string, tools *androidTools, bi *buildInfo, extraJars, pe
 	defer linkAPKZip.Close()
 
 	// Create new "APK".
-	unsignedAPK := filepath.Join(tmpDir, "app.ap_")
+	unsignedAPK := filepath.Join(tmpDir, "app.zip")
 	unsignedAPKFile, err := os.Create(unsignedAPK)
 	if err != nil {
 		return err
@@ -484,6 +506,14 @@ func exeAndroid(tmpDir string, tools *androidTools, bi *buildInfo, extraJars, pe
 			Method: f.FileHeader.Method,
 		}
 
+		if isBundle {
+			// AAB have pre-defined folders.
+			switch header.Name {
+			case "AndroidManifest.xml":
+				header.Name = "manifest/AndroidManifest.xml"
+			}
+		}
+
 		w, err := unsignedAPKZip.CreateHeader(&header)
 		if err != nil {
 			return err
@@ -525,28 +555,19 @@ func exeAndroid(tmpDir string, tools *androidTools, bi *buildInfo, extraJars, pe
 	}
 
 	// Append classes.dex.
-	if err := appendToZip("classes.dex", filepath.Join(dexDir, "classes.dex")); err != nil {
+	classesFolder := "classes.dex"
+	if isBundle {
+		classesFolder = "dex/classes.dex"
+	}
+	if err := appendToZip(classesFolder, filepath.Join(dexDir, "classes.dex")); err != nil {
 		return err
 	}
+
 	return unsignedAPKZip.Close()
 }
 
-func signAPK(tmpDir string, tools *androidTools, bi *buildInfo) error {
-	apkFile := *destPath
-	if apkFile == "" {
-		apkFile = fmt.Sprintf("%s.apk", bi.name)
-	}
-	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 {
+func signAPK(tmpDir string, apkFile string, tools *androidTools, bi *buildInfo) error {
+	if err := zipalign(tools, filepath.Join(tmpDir, "app.zip"), apkFile); err != nil {
 		return err
 	}
 
@@ -556,17 +577,94 @@ func signAPK(tmpDir string, tools *androidTools, bi *buildInfo) error {
 		}
 	}
 
-	_, err = runCmd(exec.Command(
+	_, err := runCmd(exec.Command(
 		filepath.Join(tools.buildtools, "apksigner"),
 		"sign",
 		"--ks-pass", "pass:"+bi.password,
 		"--ks", bi.key,
 		apkFile,
 	))
+
+	return err
+}
+
+func signAAB(tmpDir string, aabFile string, tools *androidTools, bi *buildInfo) error {
+	allBundleTools, err := filepath.Glob(filepath.Join(tools.buildtools, "bundletool*.jar"))
 	if err != nil {
 		return err
 	}
-	return nil
+
+	bundletool := ""
+	for _, v := range allBundleTools {
+		bundletool = v
+		break
+	}
+
+	if bundletool == "" {
+		return fmt.Errorf("bundletool was not found at %s. Download it from https://github.com/google/bundletool/releases and move to the respective folder", tools.buildtools)
+	}
+
+	_, err = runCmd(exec.Command(
+		"java",
+		"-jar", bundletool,
+		"build-bundle",
+		"--modules="+filepath.Join(tmpDir, "app.zip"),
+		"--output="+filepath.Join(tmpDir, "app.aab"),
+	))
+	if err != nil {
+		return err
+	}
+
+	if err := zipalign(tools, filepath.Join(tmpDir, "app.aab"), aabFile); err != nil {
+		return err
+	}
+
+	if bi.key == "" {
+		if err := defaultAndroidKeystore(tmpDir, bi); err != nil {
+			return err
+		}
+	}
+
+	keytoolList, err := runCmd(exec.Command(
+		"keytool",
+		"-keystore", bi.key,
+		"-list",
+		"-keypass", bi.password,
+		"-v",
+	))
+	if err != nil {
+		return err
+	}
+
+	var alias string
+	for _, t := range strings.Split(keytoolList, "\n") {
+		if i, _ := fmt.Sscanf(t, "Alias name: %s", &alias); i > 0 {
+			break
+		}
+	}
+
+	_, err = runCmd(exec.Command(
+		filepath.Join("jarsigner"),
+		"-sigalg", "SHA256withRSA",
+		"-digestalg", "SHA-256",
+		"-keystore", bi.key,
+		"-storepass", bi.password,
+		aabFile,
+		strings.TrimSpace(alias),
+	))
+
+	return err
+}
+
+func zipalign(tools *androidTools, input, output string) error {
+	_, err := runCmd(exec.Command(
+		filepath.Join(tools.buildtools, "zipalign"),
+		"-f",
+		"4", // 32-bit alignment.
+		input,
+		output,
+	))
+	return err
 }
 
 func defaultAndroidKeystore(tmpDir string, bi *buildInfo) error {

cmd/gogio/help.go

@@ -60,7 +60,7 @@ its deletion.
 
 The -x flag will print all the external commands executed by the gogio tool.
 
-The -signkey flag specifies the path of the keystore, used for signing Android apk files.
+The -signkey flag specifies the path of the keystore, used for signing Android apk/aab files.
 
 The -signpass flag specifies the password of the keystore, ignored if -signkey is not provided.
 `