cmd/gomobile: add build subcommand

Change-Id: I879e51834726c8713c5befeb4be2e328d5295af4
Reviewed-on: https://go-review.googlesource.com/4110
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

cmd/gomobile/build.go

@@ -0,0 +1,261 @@
+// 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.
+
+package main
+
+import (
+	"bytes"
+	"crypto/x509"
+	"encoding/pem"
+	"errors"
+	"flag"
+	"fmt"
+	"go/build"
+	"io"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path"
+	"path/filepath"
+	"strings"
+)
+
+var ctx = build.Default
+var pkg *build.Package
+
+var cmdBuild = &command{
+	run:   runBuild,
+	Name:  "build",
+	Usage: "[package]",
+	Short: "compile android APK and/or iOS app",
+	Long: `
+Build compiles and encodes the app named by the import path.
+
+The named package must define a main function.
+
+If an AndroidManifest.xml is defined in the package directory, it is
+added to the APK file. Otherwise, a default manifest is generated.
+
+If the package directory contains an assets subdirectory, its contents
+are copied into the APK file.
+
+These build flags are shared by the build, install, and test commands.
+For documentation, see 'go help build':
+TODO:
+	-a
+	-tags 'tag list'
+`,
+}
+
+// TODO: -n
+// TODO: -v
+// TODO: -x
+// TODO: -mobile
+
+func runBuild(cmd *command) error {
+	cwd, err := os.Getwd()
+	if err != nil {
+		panic(err)
+	}
+
+	switch len(flag.Args()) {
+	case 1:
+		pkg, err = ctx.ImportDir(cwd, build.ImportComment)
+	case 2:
+		pkg, err = ctx.Import(flag.Args()[1], cwd, build.ImportComment)
+	default:
+		cmd.usage()
+		os.Exit(1)
+	}
+	if err != nil {
+		return err
+	}
+
+	// Check that we are compiling an app.
+	if pkg.Name != "main" {
+		return fmt.Errorf(`package %q: can only build package "main"`, pkg.Name)
+	}
+	importsApp := false
+	for _, path := range pkg.Imports {
+		if path == "golang.org/x/mobile/app" {
+			importsApp = true
+			break
+		}
+	}
+	if !importsApp {
+		return fmt.Errorf(`%s does not import "golang.org/x/mobile/app"`, pkg.ImportPath)
+	}
+
+	workPath, err := ioutil.TempDir("", "gobuildapk-work-")
+	if err != nil {
+		return err
+	}
+	defer os.RemoveAll(workPath)
+
+	libName := path.Base(pkg.ImportPath)
+	manifestData, err := ioutil.ReadFile(filepath.Join(pkg.Dir, "AndroidManifest.xml"))
+	if err != nil {
+		if !os.IsNotExist(err) {
+			return err
+		}
+		buf := new(bytes.Buffer)
+		err := manifestTmpl.Execute(buf, manifestTmplData{
+			// TODO(crawshaw): a better package path.
+			JavaPkgPath: "org.golang.todo." + pkg.Name,
+			Name:        strings.ToUpper(pkg.Name[:1]) + pkg.Name[1:],
+			LibName:     libName,
+		})
+		if err != nil {
+			return err
+		}
+		// TODO(crawshaw): print generated manifest with -v.
+		manifestData = buf.Bytes()
+	} else {
+		libName, err = manifestLibName(manifestData)
+		if err != nil {
+			return err
+		}
+	}
+	libPath := filepath.Join(workPath, "lib"+libName+".so")
+
+	gopath := goEnv("GOPATH")
+	ccpath := filepath.Join(gopath, filepath.FromSlash("pkg/gomobile/android-"+ndkVersion+"/arm/bin"))
+
+	if _, err := os.Stat(ccpath); err != nil {
+		// TODO(crawshaw): call gomobile init
+		return fmt.Errorf("android %s toolchain not installed in $GOPATH/pkg/gomobile, run gomobile init", ndkVersion)
+	}
+
+	gocmd := exec.Command(
+		`go`,
+		`build`,
+		`-i`, // TODO(crawshaw): control with a flag
+		`-ldflags="-shared"`,
+		`-o`, libPath)
+	gocmd.Stdout = os.Stdout
+	gocmd.Stderr = os.Stderr
+	gocmd.Env = []string{
+		`GOOS=android`,
+		`GOARCH=arm`,
+		`GOARM=7`,
+		`CGO_ENABLED=1`,
+		`CC=` + filepath.Join(ccpath, "arm-linux-androideabi-gcc"),
+		`CXX=` + filepath.Join(ccpath, "arm-linux-androideabi-g++"),
+		`GOGCCFLAGS="-fPIC -marm -pthread -fmessage-length=0"`,
+		`GOROOT=` + goEnv("GOROOT"),
+		`GOPATH=` + gopath,
+	}
+	if err := gocmd.Run(); err != nil {
+		return err
+	}
+
+	block, _ := pem.Decode([]byte(debugCert))
+	if block == nil {
+		return errors.New("no debug cert")
+	}
+	privKey, err := x509.ParsePKCS1PrivateKey(block.Bytes)
+	if err != nil {
+		return err
+	}
+
+	// TODO: -o
+	out, err := os.Create(filepath.Base(pkg.Dir) + ".apk")
+	if err != nil {
+		return err
+	}
+
+	apkw := NewWriter(out, privKey)
+
+	w, err := apkw.Create("AndroidManifest.xml")
+	if err != nil {
+		return err
+	}
+	if _, err := w.Write(manifestData); err != nil {
+		return err
+	}
+
+	r, err := os.Open(libPath)
+	if err != nil {
+		return err
+	}
+	w, err = apkw.Create("lib/armeabi/lib" + libName + ".so")
+	if err != nil {
+		return err
+	}
+	if _, err := io.Copy(w, r); err != nil {
+		return err
+	}
+
+	// Add any assets.
+	assetsDir := filepath.Join(pkg.Dir, "assets")
+	assetsDirExists := true
+	fi, err := os.Stat(assetsDir)
+	if err != nil {
+		if os.IsNotExist(err) {
+			assetsDirExists = false
+		} else {
+			return err
+		}
+	} else {
+		assetsDirExists = fi.IsDir()
+	}
+	if assetsDirExists {
+		filepath.Walk(assetsDir, func(path string, info os.FileInfo, err error) error {
+			if err != nil {
+				return err
+			}
+			if info.IsDir() {
+				return nil
+			}
+			name := "assets/" + path[len(assetsDir)+1:]
+			w, err := apkw.Create(name)
+			if err != nil {
+				return err
+			}
+			f, err := os.Open(path)
+			if err != nil {
+				return err
+			}
+			defer f.Close()
+			_, err = io.Copy(w, f)
+			return err
+		})
+	}
+
+	// TODO: add gdbserver to apk?
+
+	return apkw.Close()
+}
+
+// A random uninteresting private key.
+// Must be consistent across builds so newer app versions can be installed.
+const debugCert = `
+-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
+`

cmd/gomobile/main.go

@@ -87,7 +87,8 @@ func help(args []string) {
 }
 
 var commands = []*command{
-	// TODO(crawshaw): cmdBuild, cmdInstall, cmdRun
+	// TODO(crawshaw): cmdInstall, cmdRun
+	cmdBuild,
 	cmdInit,
 }
 

cmd/gomobile/manifest.go

@@ -0,0 +1,78 @@
+// 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.
+
+package main
+
+import (
+	"encoding/xml"
+	"errors"
+	"fmt"
+	"html/template"
+)
+
+type manifestXML struct {
+	Activity activityXML `xml:"application>activity"`
+}
+
+type activityXML struct {
+	Name     string        `xml:"name,attr"`
+	MetaData []metaDataXML `xml:"meta-data"`
+}
+
+type metaDataXML struct {
+	Name  string `xml:"name,attr"`
+	Value string `xml:"value,attr"`
+}
+
+// manifestLibName parses the AndroidManifest.xml and finds the library
+// name of the NativeActivity.
+func manifestLibName(data []byte) (string, error) {
+	manifest := new(manifestXML)
+	if err := xml.Unmarshal(data, manifest); err != nil {
+		return "", err
+	}
+	if manifest.Activity.Name != "android.app.NativeActivity" {
+		return "", fmt.Errorf("can only build an .apk for NativeActivity, not %q", manifest.Activity.Name)
+	}
+	libName := ""
+	for _, md := range manifest.Activity.MetaData {
+		if md.Name == "android.app.lib_name" {
+			libName = md.Value
+			break
+		}
+	}
+	if libName == "" {
+		return "", errors.New("AndroidManifest.xml missing meta-data android.app.lib_name")
+	}
+	return libName, nil
+}
+
+type manifestTmplData struct {
+	JavaPkgPath string
+	Name        string
+	LibName     string
+}
+
+var manifestTmpl = template.Must(template.New("manifest").Parse(`
+<?xml version="1.0" encoding="utf-8"?>
+<manifest
+	xmlns:android="http://schemas.android.com/apk/res/android"
+	package="{{.JavaPkgPath}}"
+	android:versionCode="1"
+	android:versionName="1.0">
+
+	<uses-sdk android:minSdkVersion="9" />
+	<application android:label="{{.Name}}" android:hasCode="false" android:debuggable="true">
+	<activity android:name="android.app.NativeActivity"
+		android:label="{{.Name}}"
+		android:configChanges="orientation|keyboardHidden">
+		<meta-data android:name="android.app.lib_name" android:value="{{.LibName}}" />
+		<intent-filter>
+			<action android:name="android.intent.action.MAIN" />
+			<category android:name="android.intent.category.LAUNCHER" />
+		</intent-filter>
+	</activity>
+	</application>
+</manifest> 
+`))