Add dex example that dynamically loads a java class from a byte

stream.

.gitignore

@@ -1,3 +1,9 @@
 *.ast
 *.apk
+*.jar
+*.dex
+*.class
 examples/sensors/sensors
+examples/jni/jni
+examples/dex/dex
+examples/permissions/permissions

examples/dex/bindata.go

@@ -0,0 +1,237 @@
+// Code generated by go-bindata.
+// sources:
+// java/classes.dex
+// DO NOT EDIT!
+
+package main
+
+import (
+	"bytes"
+	"compress/gzip"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+func bindataRead(data []byte, name string) ([]byte, error) {
+	gz, err := gzip.NewReader(bytes.NewBuffer(data))
+	if err != nil {
+		return nil, fmt.Errorf("Read %q: %v", name, err)
+	}
+
+	var buf bytes.Buffer
+	_, err = io.Copy(&buf, gz)
+	clErr := gz.Close()
+
+	if err != nil {
+		return nil, fmt.Errorf("Read %q: %v", name, err)
+	}
+	if clErr != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}
+
+type asset struct {
+	bytes []byte
+	info  os.FileInfo
+}
+
+type bindataFileInfo struct {
+	name    string
+	size    int64
+	mode    os.FileMode
+	modTime time.Time
+}
+
+func (fi bindataFileInfo) Name() string {
+	return fi.name
+}
+func (fi bindataFileInfo) Size() int64 {
+	return fi.size
+}
+func (fi bindataFileInfo) Mode() os.FileMode {
+	return fi.mode
+}
+func (fi bindataFileInfo) ModTime() time.Time {
+	return fi.modTime
+}
+func (fi bindataFileInfo) IsDir() bool {
+	return false
+}
+func (fi bindataFileInfo) Sys() interface{} {
+	return nil
+}
+
+var _javaClassesDex = []byte("\x1f\x8b\x08\x00\x00\x00\x00\x00\x00\xff\x5c\x91\xbf\x4e\xc2\x50\x14\xc6\x7f\xa7\xe5\x4f\x22\x06\x11\x4d\x5c\x88\xe9\xa0\xab\x57\x23\x4e\x18\x13\xe3\x22\x09\xd1\x8d\xa5\x53\x15\x24\x25\x88\xc4\x56\x61\xd4\x84\x91\x47\xd0\xcd\x47\xf0\x11\x1c\x1c\x1c\xf4\x21\xdc\x58\xdc\x1d\xcc\xed\xbd\x40\xe3\x49\xda\xef\xe4\xf4\x9e\xef\x9c\xfe\x6e\xab\x3d\x5a\xda\xdd\x3f\xa0\x5e\xfd\x2c\xbf\xff\x3e\x7f\x7f\xbd\x6c\xbe\xf9\xcd\x1f\xff\xd6\x5f\x9f\xf8\x8d\xca\xf6\xb2\x03\x03\x60\xd4\xac\x96\xb1\x31\x16\xc8\x63\xea\x19\x60\x02\x38\xc0\x13\x8b\x70\x81\x57\x40\x80\x0f\xc0\x13\x98\x02\x15\x81\x2d\x81\x3d\x81\xaa\xc0\xa9\x40\x20\x70\x25\xc6\xc3\xb5\x9e\x39\xeb\x39\x8b\x9c\xfd\x46\xe2\x29\x89\x3a\x73\x85\xac\x55\xb1\x0f\x29\x8d\x64\xd1\xa7\xd3\x50\xcc\x8c\x41\x49\x57\x8b\x73\x9f\xbe\x98\x19\x6b\xac\xb2\xa2\x67\x1e\x86\xfd\x30\x3e\xa2\x70\x7c\xd2\x0b\xa2\x68\xa7\x1b\xdc\x07\x48\x9d\x72\x43\x67\xaa\x17\xf4\x3b\xea\xfc\xa2\xdb\xbe\x8c\x6b\x6c\x34\xa2\x58\x0d\x6f\x86\xaa\x13\xc6\xaa\xd5\x1e\x29\xd3\x53\xc3\x3d\xbb\xbb\x46\x9a\xb8\xe4\x8b\x64\xf5\x0b\x44\xe4\xf1\x21\x33\x15\x47\xc6\x7a\xe7\xc2\xbf\x7d\xb5\xce\xf8\x3a\x29\xc6\x6e\x8a\x73\x36\xc5\x38\x97\xe2\x2c\x9e\x39\xa3\x59\x3b\x9e\xf1\xd1\xcc\x5d\x5b\xd7\xff\x8e\x67\xce\x27\x5c\x4a\x26\xd7\x77\xfa\x17\x00\x00\xff\xff\xe4\x6b\xad\x5e\x0c\x02\x00\x00")
+
+func javaClassesDexBytes() ([]byte, error) {
+	return bindataRead(
+		_javaClassesDex,
+		"java/classes.dex",
+	)
+}
+
+func javaClassesDex() (*asset, error) {
+	bytes, err := javaClassesDexBytes()
+	if err != nil {
+		return nil, err
+	}
+
+	info := bindataFileInfo{name: "java/classes.dex", size: 524, mode: os.FileMode(420), modTime: time.Unix(1572550715, 0)}
+	a := &asset{bytes: bytes, info: info}
+	return a, nil
+}
+
+// Asset loads and returns the asset for the given name.
+// It returns an error if the asset could not be found or
+// could not be loaded.
+func Asset(name string) ([]byte, error) {
+	cannonicalName := strings.Replace(name, "\\", "/", -1)
+	if f, ok := _bindata[cannonicalName]; ok {
+		a, err := f()
+		if err != nil {
+			return nil, fmt.Errorf("Asset %s can't read by error: %v", name, err)
+		}
+		return a.bytes, nil
+	}
+	return nil, fmt.Errorf("Asset %s not found", name)
+}
+
+// MustAsset is like Asset but panics when Asset would return an error.
+// It simplifies safe initialization of global variables.
+func MustAsset(name string) []byte {
+	a, err := Asset(name)
+	if err != nil {
+		panic("asset: Asset(" + name + "): " + err.Error())
+	}
+
+	return a
+}
+
+// AssetInfo loads and returns the asset info for the given name.
+// It returns an error if the asset could not be found or
+// could not be loaded.
+func AssetInfo(name string) (os.FileInfo, error) {
+	cannonicalName := strings.Replace(name, "\\", "/", -1)
+	if f, ok := _bindata[cannonicalName]; ok {
+		a, err := f()
+		if err != nil {
+			return nil, fmt.Errorf("AssetInfo %s can't read by error: %v", name, err)
+		}
+		return a.info, nil
+	}
+	return nil, fmt.Errorf("AssetInfo %s not found", name)
+}
+
+// AssetNames returns the names of the assets.
+func AssetNames() []string {
+	names := make([]string, 0, len(_bindata))
+	for name := range _bindata {
+		names = append(names, name)
+	}
+	return names
+}
+
+// _bindata is a table, holding each asset generator, mapped to its name.
+var _bindata = map[string]func() (*asset, error){
+	"java/classes.dex": javaClassesDex,
+}
+
+// AssetDir returns the file names below a certain
+// directory embedded in the file by go-bindata.
+// For example if you run go-bindata on data/... and data contains the
+// following hierarchy:
+//     data/
+//       foo.txt
+//       img/
+//         a.png
+//         b.png
+// then AssetDir("data") would return []string{"foo.txt", "img"}
+// AssetDir("data/img") would return []string{"a.png", "b.png"}
+// AssetDir("foo.txt") and AssetDir("notexist") would return an error
+// AssetDir("") will return []string{"data"}.
+func AssetDir(name string) ([]string, error) {
+	node := _bintree
+	if len(name) != 0 {
+		cannonicalName := strings.Replace(name, "\\", "/", -1)
+		pathList := strings.Split(cannonicalName, "/")
+		for _, p := range pathList {
+			node = node.Children[p]
+			if node == nil {
+				return nil, fmt.Errorf("Asset %s not found", name)
+			}
+		}
+	}
+	if node.Func != nil {
+		return nil, fmt.Errorf("Asset %s not found", name)
+	}
+	rv := make([]string, 0, len(node.Children))
+	for childName := range node.Children {
+		rv = append(rv, childName)
+	}
+	return rv, nil
+}
+
+type bintree struct {
+	Func     func() (*asset, error)
+	Children map[string]*bintree
+}
+var _bintree = &bintree{nil, map[string]*bintree{
+	"java": &bintree{nil, map[string]*bintree{
+		"classes.dex": &bintree{javaClassesDex, map[string]*bintree{}},
+	}},
+}}
+
+// RestoreAsset restores an asset under the given directory
+func RestoreAsset(dir, name string) error {
+	data, err := Asset(name)
+	if err != nil {
+		return err
+	}
+	info, err := AssetInfo(name)
+	if err != nil {
+		return err
+	}
+	err = os.MkdirAll(_filePath(dir, filepath.Dir(name)), os.FileMode(0755))
+	if err != nil {
+		return err
+	}
+	err = ioutil.WriteFile(_filePath(dir, name), data, info.Mode())
+	if err != nil {
+		return err
+	}
+	err = os.Chtimes(_filePath(dir, name), info.ModTime(), info.ModTime())
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// RestoreAssets restores an asset under the given directory recursively
+func RestoreAssets(dir, name string) error {
+	children, err := AssetDir(name)
+	// File
+	if err != nil {
+		return RestoreAsset(dir, name)
+	}
+	// Dir
+	for _, child := range children {
+		err = RestoreAssets(dir, filepath.Join(name, child))
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func _filePath(dir, name string) string {
+	cannonicalName := strings.Replace(name, "\\", "/", -1)
+	return filepath.Join(append([]string{dir}, strings.Split(cannonicalName, "/")...)...)
+}
+

examples/dex/dex_android.go

@@ -0,0 +1,206 @@
+package main
+
+/*
+#cgo LDFLAGS: -landroid -llog
+
+#include <stdlib.h>
+#include <jni.h>
+#include <android/log.h>
+
+static jobject gClassLoader;
+static jmethodID gFindClassMethod;
+
+jobject
+CreateObject(JNIEnv* env, jclass cls) {
+        jmethodID init = (*env)->GetMethodID(env, cls, "<init>", "()V");
+        return (*env)->NewObject(env, cls, init);
+}
+
+jmethodID GetMethodID(JNIEnv *env, jclass cls, const char *name, const char *sig) {
+	return (*env)->GetMethodID(env, cls, name, sig);
+}
+
+jclass
+FindClass(JNIEnv* env, char* name) {
+	jstring strClassName = (*env)->NewStringUTF(env, name);
+	return (*env)->CallObjectMethod(env, gClassLoader, gFindClassMethod, strClassName);
+}
+
+void
+SetupJVM(JNIEnv* env, jobject context, void* buf, int len) {
+	jclass cls = (*env)->GetObjectClass(env, context);
+	jmethodID mid = (*env)->GetMethodID(env, cls, "getClassLoader", "()Ljava/lang/ClassLoader;");
+	jobject loader = (*env)->CallObjectMethod(env, context, mid);
+	gClassLoader = (*env)->NewGlobalRef(env, loader);
+	cls = (*env)->GetObjectClass(env, loader);
+	gFindClassMethod = (*env)->GetMethodID(env, cls, "findClass", "(Ljava/lang/String;)Ljava/lang/Class;");
+
+	__android_log_write(ANDROID_LOG_DEBUG, "gio", "Looking for InMemoryDexClassLoader");
+	cls = (*env)->FindClass(env, "dalvik/system/InMemoryDexClassLoader");
+	if (cls == NULL) {
+		__android_log_write(ANDROID_LOG_DEBUG, "gio", "not found");
+		return;
+	}
+	__android_log_write(ANDROID_LOG_DEBUG, "gio", "NewDirectByteBuffer");
+	jobject bbuf = (*env)->NewDirectByteBuffer(env, buf, (jlong)len);
+	if (bbuf == NULL) {
+		__android_log_write(ANDROID_LOG_DEBUG, "gio", "failed");
+		return;
+	}
+
+	__android_log_write(ANDROID_LOG_DEBUG, "gio", "looking for <init>");
+	mid = (*env)->GetMethodID(env, cls, "<init>", "(Ljava/nio/ByteBuffer;Ljava/lang/ClassLoader;)V");
+	if (mid == NULL) {
+		__android_log_write(ANDROID_LOG_DEBUG, "gio", "not found");
+		return;
+	}
+	__android_log_write(ANDROID_LOG_DEBUG, "gio", "calling <init>");
+	jobject dexLoader = (*env)->NewObject(env, cls, mid, bbuf, gClassLoader);
+	// make the dexLoader our new class loader
+	gClassLoader = (*env)->NewGlobalRef(env, dexLoader);
+}
+
+//	__android_log_write(ANDROID_LOG_DEBUG, "gio", "looking for AClass");
+//	cls = FindClass(env, "st/wow/git/dex/AClass");
+//	if (cls == NULL) {
+//		__android_log_write(ANDROID_LOG_DEBUG, "gio", "not found");
+//		return;
+//	}
+//
+//	__android_log_write(ANDROID_LOG_DEBUG, "gio", "calling CreateObject");
+//	jobject obj = CreateObject(env, cls);
+//	if (obj == NULL) {
+//		__android_log_write(ANDROID_LOG_DEBUG, "gio", "failed");
+//		return;
+//	}
+//
+//	__android_log_write(ANDROID_LOG_DEBUG, "gio", "looking for <init>");
+//	mid = (*env)->GetMethodID(env, cls, "<init>", "()V");
+//	if (mid == NULL) {
+//		__android_log_write(ANDROID_LOG_DEBUG, "gio", "not found");
+//		return;
+//	}
+//	__android_log_write(ANDROID_LOG_DEBUG, "gio", "creating object");
+//	obj = (*env)->NewObject(env, cls, mid);
+//	if (obj == NULL) {
+//		__android_log_write(ANDROID_LOG_DEBUG, "gio", "failed");
+//		return;
+//	}
+//
+//	__android_log_write(ANDROID_LOG_DEBUG, "gio", "looking for Num");
+//	mid = (*env)->GetMethodID(env, cls, "Num", "()I");
+//	if (mid == NULL) {
+//		__android_log_write(ANDROID_LOG_DEBUG, "gio", "not found");
+//		return;
+//	}
+//	jint val = (*env)->CallIntMethod(env, obj, mid);
+//	__android_log_print(ANDROID_LOG_DEBUG, "gio", "value = %d", val);
+
+
+jint
+CallIntMethod(JNIEnv *env, jobject obj, jmethodID methodID) {
+	return (*env)->CallIntMethod(env, obj, methodID);
+}
+
+jint
+GetEnv(JavaVM *vm, JNIEnv **env, jint version) {
+	return (*vm)->GetEnv(vm, (void **)env, version);
+}
+
+jint
+AttachCurrentThread(JavaVM *vm, JNIEnv **p_env, void *thr_args) {
+	return (*vm)->AttachCurrentThread(vm, p_env, thr_args);
+}
+
+jint
+DetachCurrentThread(JavaVM *vm) {
+	return (*vm)->DetachCurrentThread(vm);
+}
+
+*/
+import "C"
+
+import (
+	"errors"
+	"fmt"
+	"runtime"
+	"unsafe"
+
+	"gioui.org/app"
+)
+
+var theJVM *C.JavaVM
+
+func SetJVM() {
+	h := app.PlatformHandle()
+	theJVM = (*C.JavaVM)(unsafe.Pointer(h.JVM))
+	dex := MustAsset("java/classes.dex")
+	RunInJVM(func(env *C.JNIEnv) {
+		labchan <- "Set up JVM"
+		C.SetupJVM(
+			env,
+			(C.jobject)(h.Context),
+			unsafe.Pointer(&dex[0]),
+			C.int(len(dex)),
+		)
+	})
+}
+
+func CallJNI() {
+	labchan <- "Call JNI"
+	RunInJVM(func(env *C.JNIEnv) {
+		labchan <- "FindClass"
+		cls := JniFindClass(env, "st/wow/git/dex/AClass")
+		labchan <- "GetMethodID"
+		mid := JniGetMethodID(env, cls, "Num", "()I")
+		labchan <- "CreateObject"
+		obj := JniCreateObject(env, cls)
+		val := JniCallIntMethod(env, obj, mid)
+		labchan <- fmt.Sprintf("val = %d", val)
+	})
+}
+
+func JniFindClass(env *C.JNIEnv, name string) C.jclass {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+	return C.FindClass((*C.JNIEnv)(env), cname)
+}
+
+func JniCreateObject(env *C.JNIEnv, cls C.jclass) C.jobject {
+	return C.CreateObject(env, (C.jclass)(cls))
+}
+
+func JniCallIntMethod(env *C.JNIEnv, obj C.jobject, methodID C.jmethodID) int {
+	return (int)(C.CallIntMethod(env, obj, methodID))
+}
+
+func JniGetMethodID(env *C.JNIEnv, cls C.jclass, name, sig string) C.jmethodID {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+	csig := C.CString(sig)
+	defer C.free(unsafe.Pointer(csig))
+	return C.GetMethodID(env, cls, cname, csig)
+}
+
+func RunInJVM(f func(env *C.JNIEnv)) {
+        runtime.LockOSThread()
+        defer runtime.UnlockOSThread()
+        var env *C.JNIEnv
+        var detach bool
+        if res := C.GetEnv(theJVM, &env, C.JNI_VERSION_1_6); res != C.JNI_OK {
+                if res != C.JNI_EDETACHED {
+                        panic(fmt.Errorf("JNI GetEnv failed with error %d", res))
+                }
+                if C.AttachCurrentThread(theJVM, &env, nil) != C.JNI_OK {
+                        panic(errors.New("runInJVM: AttachCurrentThread failed"))
+                }
+                detach = true
+        }
+
+        if detach {
+                defer func() {
+                        C.DetachCurrentThread(theJVM)
+                }()
+        }
+        f(env)
+}

examples/dex/dex_other.go

@@ -0,0 +1,9 @@
+package main
+
+func SetJVM() {
+	dex := MustAsset("java/classes.dex")
+	_ = dex
+}
+
+func CallJNI() {
+}

examples/dex/java/AClass.java

@@ -0,0 +1,9 @@
+package st.wow.git.dex;
+
+public class AClass {
+	public int Num() {
+		return 17;
+	}
+}
+
+

examples/dex/java/gen.go

@@ -0,0 +1,5 @@
+//go:generate javac -bootclasspath $ANDROID_HOME/platforms/android-29/android.jar AClass.java
+//go:generate $ANDROID_HOME/build-tools/28.0.3/dx --dex --output=classes.dex --no-strict AClass.class
+//go:generate rm AClass.class
+
+package java

examples/dex/main.go

@@ -0,0 +1,70 @@
+//go:generate go generate ./java
+//go:generate go-bindata java/classes.dex
+
+package main
+
+import (
+	"gioui.org/app"
+	"gioui.org/layout"
+	"gioui.org/io/system"
+	"gioui.org/unit"
+	"gioui.org/widget/material"
+
+	"gioui.org/font/gofont"
+)
+
+var (
+	labchan chan string
+)
+
+func main() {
+	labchan = make(chan string)
+	go eventloop()
+	app.Main()
+}
+
+func eventloop() {
+	gofont.Register()
+	w := app.NewWindow(app.Title("Dex"))
+	th := material.NewTheme()
+	gtx := &layout.Context{Queue: w.Queue()}
+
+	sysinset := &layout.Inset{}
+	margin := layout.UniformInset(unit.Dp(10))
+	labels := []material.Label{}
+	list := &layout.List{Axis: layout.Vertical}
+
+	go func() {
+		labchan <- "Starting"
+		SetJVM()
+		CallJNI()
+	}()
+
+	resetSysinset := func(x system.Insets) {
+		sysinset.Top = x.Top
+		sysinset.Bottom = x.Bottom
+		sysinset.Left = x.Left
+		sysinset.Right = x.Right
+	}
+
+	for { select {
+		case x := <-labchan:
+			labels = append(labels, th.Body1(x))
+		case e := <-w.Events():
+		switch e := e.(type) {
+		case system.DestroyEvent:
+			return
+		case system.FrameEvent:
+			gtx.Reset(e.Config, e.Size)
+			resetSysinset(e.Insets)
+			sysinset.Layout(gtx, func() {
+				margin.Layout(gtx, func() {
+					list.Layout(gtx, len(labels), func(i int) {
+						labels[i].Layout(gtx)
+					})
+				})
+			})
+			e.Frame(gtx.Ops)
+		}
+	}}
+}

examples/jni/main.go

@@ -26,13 +26,6 @@ func main() {
 	log.Print("app.Main() returned")
 }
 
-func diffInsets(x, y system.Insets) bool {
-	return x.Top != y.Top ||
-		x.Bottom != y.Bottom ||
-		x.Left != y.Left ||
-		x.Right != y.Right
-}
-
 func eventloop() {
 	w := app.NewWindow(
 		app.Size(unit.Dp(400), unit.Dp(400)),

examples/sensors/main.go

@@ -11,7 +11,7 @@ import (
 	"gioui.org/unit"
 	"gioui.org/widget/material"
 
-	_ "gioui.org/font/gofont"
+	"gioui.org/font/gofont"
 )
 
 var (
@@ -34,6 +34,7 @@ func diffInsets(x, y system.Insets) bool {
 }
 
 func eventloop() {
+	gofont.Register()
 	w := app.NewWindow(
 		app.Size(unit.Dp(400), unit.Dp(400)),
 		app.Title("Hello"))

go.mod

@@ -1,8 +1,3 @@
 module git.wow.st/gmp/android-go
 
 go 1.13
-
-require (
-	gioui.org v0.0.0-20191018181617-5ef176af8145
-	golang.org/x/image v0.0.0-20190910094157-69e4b8554b2a
-)