Support scanning QR Code for receiving files

QR Codes can be generated from the wormwhole-william cli tool via the
`--qr` flag.

The code embeds the relay url, but currently we are ignoring that and
just using the relay set in the config.

Closes: #7 [via git-merge-pr]

android/build.gradle

@@ -37,4 +37,7 @@ android {
 
 dependencies {
     implementation ':wormhole-william@aar'
+    implementation 'com.android.support:appcompat-v7:26.1.0'
+    compile 'com.google.zxing:core:3.2.1'
+    compile 'com.journeyapps:zxing-android-embedded:3.2.0@aar'
 }

android/src/main/AndroidManifest.xml

@@ -1,6 +1,8 @@
 <?xml version="1.0" encoding="utf-8" standalone="no"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
-          package="io.sanford.wormhole_william">
+          package="io.sanford.wormhole_william"
+          xmlns:tools="http://schemas.android.com/tools"
+          >
   <uses-permission android:name="android.permission.INTERNET"/>
   <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
 
@@ -28,5 +30,13 @@
         <data android:mimeType="*/*" />
       </intent-filter>
     </activity>
+
+    <activity
+        android:name="com.journeyapps.barcodescanner.CaptureActivity"
+        android:screenOrientation="portrait"
+        tools:replace="android:screenOrientation"
+        android:stateNotNeeded="true">
+    </activity>
+
   </application>
 </manifest>

android/src/main/java/io/sanford/wormholewilliam/Scan.java

@@ -0,0 +1,54 @@
+package io.sanford.wormholewilliam;
+
+import android.app.Activity;
+import android.app.Fragment;
+import android.app.FragmentTransaction;
+import android.content.Context;
+import android.content.Intent;
+import android.os.Handler;
+import android.util.Log;
+import android.view.View;
+import com.google.zxing.integration.android.IntentIntegrator;
+import com.google.zxing.integration.android.IntentResult;
+import java.lang.String;
+
+public class Scan extends Fragment {
+  public Scan() {
+  }
+
+  public void register(View view) {
+    Context ctx = view.getContext();
+    Handler handler = new Handler(ctx.getMainLooper());
+    Scan inst = this;
+    handler.post(new Runnable() {
+        public void run() {
+          Activity act = (Activity)ctx;
+          FragmentTransaction ft = act.getFragmentManager().beginTransaction();
+          ft.add(inst, "Scan");
+          ft.commitNow();
+        }
+      });
+  }
+
+  @Override public void onAttach(Context ctx) {
+    super.onAttach(ctx);
+
+    IntentIntegrator integrator = IntentIntegrator.forFragment(this);
+    integrator.setDesiredBarcodeFormats(IntentIntegrator.QR_CODE_TYPES);
+    integrator.setPrompt("Scan");
+    integrator.setCameraId(0);
+    integrator.setBeepEnabled(false);
+    integrator.setBarcodeImageEnabled(false);
+    integrator.initiateScan();
+  }
+
+  @Override public void onActivityResult(int requestCode, int resultCode, Intent data) {
+    IntentResult result = IntentIntegrator.parseActivityResult(requestCode, resultCode, data);
+    if(result != null) {
+      Log.d("wormhole", "Scan.onActivityResult() " + result.getContents());
+      scanResult(result.getContents());
+    }
+  }
+
+  static private native void scanResult(String contents);
+}

jgo/jgo.go

@@ -20,10 +20,10 @@ import (
 )
 
 var (
-	globalStateMux sync.Mutex
-	pendingResult  chan picker.PickResult
-
-	sharedEventCh chan picker.SharedEvent
+	globalStateMux      sync.Mutex
+	pendingResult       chan picker.PickResult
+	pendingQRScanResult chan string
+	sharedEventCh       chan picker.SharedEvent
 )
 
 func PickFile(viewEvt app.ViewEvent) <-chan picker.PickResult {
@@ -101,6 +101,42 @@ func NotifyDownloadManager(viewEvt app.ViewEvent, name, path, contentType string
 	}()
 }
 
+func ScanQRCode(viewEvt app.ViewEvent) chan string {
+	globalStateMux.Lock()
+	pendingQRScanResult = make(chan string, 1)
+	globalStateMux.Unlock()
+
+	go func() {
+		jvm := jni.JVMFor(app.JavaVM())
+		err := jni.Do(jvm, func(env jni.Env) error {
+			var uptr = app.AppContext()
+			appCtx := *(*jni.Object)(unsafe.Pointer(&uptr))
+			loader := jni.ClassLoaderFor(env, appCtx)
+			cls, err := jni.LoadClass(env, loader, "io.sanford.wormholewilliam.Scan")
+			if err != nil {
+				log.Printf("Load io.sanford.wormholewilliam.Scan error: %s", err)
+			}
+
+			mid := jni.GetMethodID(env, cls, "<init>", "()V")
+
+			inst, err := jni.NewObject(env, cls, mid)
+			if err != nil {
+				log.Printf("NewObject err: %s", err)
+			}
+			sig := "(Landroid/view/View;)V"
+
+			mid = jni.GetMethodID(env, cls, "register", sig)
+
+			return jni.CallVoidMethod(env, inst, mid, jni.Value(viewEvt.View))
+		})
+		if err != nil {
+			log.Printf("ScnQRCode jvm err: %s", err)
+		}
+	}()
+
+	return pendingQRScanResult
+}
+
 //export Java_io_sanford_wormholewilliam_Jni_pickerResult
 func Java_io_sanford_wormholewilliam_Jni_pickerResult(env *C.JNIEnv, cls C.jclass, jpath, jname, jerr C.jstring) {
 
@@ -164,3 +200,23 @@ func Java_io_sanford_wormholewilliam_Share_gotSharedItem(env *C.JNIEnv, cls C.jc
 		log.Printf("sharedEvent send timeout")
 	}
 }
+
+//export Java_io_sanford_wormholewilliam_Scan_scanResult
+func Java_io_sanford_wormholewilliam_Scan_scanResult(env *C.JNIEnv, cls C.jclass, jCode C.jstring) {
+	globalStateMux.Lock()
+	defer globalStateMux.Unlock()
+	if pendingQRScanResult == nil {
+		return
+	}
+
+	jenv := jni.EnvFor(uintptr(unsafe.Pointer(env)))
+	code := jni.GoString(jenv, jni.String(jCode))
+
+	log.Printf("scan code result: %s", code)
+
+	select {
+	case pendingQRScanResult <- code:
+	case <-time.After(10 * time.Second):
+		log.Printf("pendingQRScanResult send timeout")
+	}
+}

ui/platform_android.go

@@ -30,6 +30,10 @@ func (a *androidPlatform) notifyDownloadManager(name, path, contentType string,
 
 }
 
-func (d *androidPlatform) sharedEventCh() chan picker.SharedEvent {
+func (a *androidPlatform) sharedEventCh() chan picker.SharedEvent {
 	return jgo.GetSharedEventCh()
 }
+
+func (a *androidPlatform) scanQRCode() <-chan string {
+	return jgo.ScanQRCode(a.viewEvent)
+}

ui/platform_dummy.go

@@ -33,3 +33,7 @@ func (d *dummyPlatform) notifyDownloadManager(name, path, contentType string, si
 func (d *dummyPlatform) sharedEventCh() chan picker.SharedEvent {
 	return nil
 }
+
+func (d *dummyPlatform) scanQRCode() <-chan string {
+	return nil
+}

ui/ui.go

@@ -2,13 +2,15 @@ package ui
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"image"
 	"image/color"
 	"io"
 	"io/ioutil"
 	"log"
 	"net/http"
+	"net/url"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -67,7 +69,8 @@ func (ui *UI) loop(w *app.Window) error {
 	}
 
 	var (
-		pickResult <-chan picker.PickResult
+		pickResult   <-chan picker.PickResult
+		qrCodeResult <-chan string
 
 		ctx             = context.Background()
 		platformHandler = newPlatformHandler()
@@ -76,6 +79,19 @@ func (ui *UI) loop(w *app.Window) error {
 	var ops op.Ops
 	for {
 		select {
+		case code := <-qrCodeResult:
+			if code != "" {
+
+				parsed, err := parseCodeURI(code)
+				if err != nil {
+					statusMsg = fmt.Sprintf("invalid code: %s", err)
+					continue
+				}
+
+				recvCodeEditor.SetText(parsed.code)
+				w.Invalidate()
+			}
+			qrCodeResult = nil
 		case shareEvt := <-platformHandler.sharedEventCh():
 			if shareEvt.Type == picker.Text {
 				textMsgEditor.SetText(shareEvt.Text)
@@ -117,6 +133,7 @@ func (ui *UI) loop(w *app.Window) error {
 					sendFileClicked bool
 					sendTextClicked bool
 					recvClicked     bool
+					scanQRClicked   bool
 					acceptClicked   bool
 					cancelClicked   bool
 				)
@@ -129,6 +146,7 @@ func (ui *UI) loop(w *app.Window) error {
 					{"sendFileBtn", sendFileBtn, &sendFileClicked},
 					{"sendTextBtn", sendTextBtn, &sendTextClicked},
 					{"recvMsgBtn", recvMsgBtn, &recvClicked},
+					{"scanQRBtn", scanQRBtn, &scanQRClicked},
 					{"acceptBtn", acceptBtn, &acceptClicked},
 					{"cancelBtn", cancelBtn, &cancelClicked},
 				}
@@ -153,6 +171,10 @@ func (ui *UI) loop(w *app.Window) error {
 					}
 				}
 
+				if scanQRClicked {
+					qrCodeResult = platformHandler.scanQRCode()
+				}
+
 				if sendFileClicked {
 					pickResult = platformHandler.pickFile()
 				}
@@ -489,6 +511,7 @@ var (
 
 	recvCodeEditor = new(RichEditor)
 	recvMsgBtn     = new(widget.Clickable)
+	scanQRBtn      = new(widget.Clickable)
 	recvTxtMsg     = new(Copyable)
 	itemList       = &layout.List{
 		Axis: layout.Vertical,
@@ -652,6 +675,12 @@ var recvTab = Tab{
 		widgets := []layout.Widget{
 			textField(gtx, th, "Code", "Code", recvCodeEditor),
 
+			func(gtx C) D {
+				if transferInProgress || recvCodeEditor.Text() != "" {
+					gtx = gtx.Disabled()
+				}
+				return material.Button(th, scanQRBtn, "Scan QR Code").Layout(gtx)
+			},
 			func(gtx C) D {
 				if transferInProgress {
 					gtx = gtx.Disabled()
@@ -802,6 +831,7 @@ type platformHandler interface {
 	pickFile() <-chan picker.PickResult
 	sharedEventCh() chan picker.SharedEvent
 	notifyDownloadManager(name, path, contentType string, size int64)
+	scanQRCode() <-chan string
 }
 
 // Test colors.
@@ -821,3 +851,31 @@ func ColorBox(gtx layout.Context, size image.Point, color color.NRGBA) layout.Di
 	paint.PaintOp{}.Add(gtx.Ops)
 	return layout.Dimensions{Size: size}
 }
+
+type parsedCode struct {
+	relay string
+	code  string
+}
+
+func parseCodeURI(codeStr string) (*parsedCode, error) {
+	if !strings.HasPrefix(codeStr, "wormhole:") {
+		return nil, errors.New("not a wormhole code")
+	}
+
+	u := strings.TrimPrefix(codeStr, "wormhole:")
+
+	url, err := url.Parse(u)
+	if err != nil {
+		return nil, err
+	}
+
+	code := url.Query().Get("code")
+	if code == "" {
+		return nil, errors.New("no code")
+	}
+
+	return &parsedCode{
+		relay: url.Host,
+		code:  code,
+	}, nil
+}