Add support for webapk without runtimeHost

chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/WebApkUtils.java

 // Copyright 2016 The Chromium 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 org.chromium.webapk.shell_apk;
 
 import android.content.Context;
+import android.content.Intent;
+import android.content.SharedPreferences;
 import android.content.pm.ApplicationInfo;
 import android.content.pm.PackageManager;
 import android.content.pm.PackageManager.NameNotFoundException;
+import android.content.pm.ResolveInfo;
+import android.graphics.drawable.Drawable;
+import android.net.Uri;
 import android.os.Bundle;
+import android.text.TextUtils;
 
+import org.chromium.webapk.lib.common.WebApkConstants;
 import org.chromium.webapk.lib.common.WebApkMetaDataKeys;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
 /**
  * Contains utility methods for interacting with WebAPKs.
  */
 public class WebApkUtils {
+    public static final String SHARED_PREF_RUNTIME_HOST = "runtime_host";
+
+    // The package names of the channels of Chrome that support WebAPKs. The most preferred one
+    // comes first.

[pkotwicz, 2017/05/26 22:38:39]

Nit: use block commenting style

[Xi Han, 2017/05/29 21:18:56]

Done.

+    private static List<String> sBrowsersSupportingWebApk = new ArrayList<String>(
+            Arrays.asList("com.google.android.apps.chrome", "com.android.chrome", "com.chrome.beta",
+                    "com.chrome.dev", "com.chrome.canary"));
 
     /**
-     * Caches the value read from Application Metadata which specifies the host browser's package
-     * name.
+     * Stores information about a potential host browser for the WebAPK.
+     */
+    public static class BrowserItem {
+        private String mPackageName;
+        private CharSequence mApplicationLabel;
+        private Drawable mIcon;
+        private boolean mIsEnabled;

[pkotwicz, 2017/05/26 22:38:39]

WebApkUtils should not know about the UI in which BrowserItem is used. Maybe
rename this variable to mSupportsWebApks

[Xi Han, 2017/05/29 21:18:56]

Done.

+
+        public BrowserItem(String packageName, CharSequence applicationLabel, Drawable icon,
+                boolean isEnabled) {
+            mPackageName = packageName;
+            mApplicationLabel = applicationLabel;
+            mIcon = icon;
+            mIsEnabled = isEnabled;
+        }
+
+        // Returns the package name of a browser.

[pkotwicz, 2017/05/26 22:38:39]

Nit: Use /** */ for comments in this class.
https://google.github.io/styleguide/javaguide.html#s7.1.1-javadoc-multi-line

[Xi Han, 2017/05/29 21:18:56]

Thanks!

+        public String getPackageName() {
+            return mPackageName;
+        }
+
+        // Returns the application name of a browser.
+        public CharSequence getApplicationName() {
+            return mApplicationLabel;
+        }
+
+        // Returns a drawable of the browser icon.
+        public Drawable getApplicationIcon() {
+            return mIcon;
+        }
+
+        // Returns whether this BrowserItem is clickable. An BrowserItem is clickable only if the
+        // browser it represents supporting WebAPKs.
+        public boolean isEnabled() {
+            return mIsEnabled;
+        }
+    }
+
+    /**
+     * Caches the package name of the host browser. {@link sHostPackage} might refer to a browser
+     * which has been uninstalled. A notification can keep the WebAPK process alive after the host
+     * browser has been uninstalled.
      */
     private static String sHostPackage;
 
+    // For testing only.
+    public static void resetCachedHostPackageForTesting() {
+        sHostPackage = null;
+    }
+
+    public static void setBrowsersSupportingWebApkForTesting(List<String> browsers) {
+        sBrowsersSupportingWebApk = browsers;
+    }
+
     /**
      * Returns a Context for the host browser that was specified when building the WebAPK.
      * @param context A context.
      * @return The remote context. Returns null on an error.
      */
     public static Context getHostBrowserContext(Context context) {
         try {
             String hostPackage = getHostBrowserPackageName(context);
             return context.getApplicationContext().createPackageContext(
                             hostPackage,
                             Context.CONTEXT_IGNORE_SECURITY | Context.CONTEXT_INCLUDE_CODE);
         } catch (NameNotFoundException e) {
             e.printStackTrace();
         }
         return null;
     }
 
     /**
-     * Returns the package name for the host browser that was specified when building the WebAPK.
+     * Returns the package name of the host browser to launch the WebAPK. Also caches the package
+     * name in the SharedPreference if it is not null.
      * @param context A context.
      * @return The package name. Returns null on an error.
      */
     public static String getHostBrowserPackageName(Context context) {
-        if (sHostPackage != null) return sHostPackage;
-        String hostPackage = null;
-        try {
-            ApplicationInfo ai = context.getPackageManager().getApplicationInfo(
-                    context.getPackageName(), PackageManager.GET_META_DATA);
-            Bundle bundle = ai.metaData;
-            hostPackage = bundle.getString(WebApkMetaDataKeys.RUNTIME_HOST);
-        } catch (NameNotFoundException e) {
-            e.printStackTrace();
+        if (sHostPackage == null) {
+            sHostPackage = getHostBrowserPackageNameInternal(context);
+            if (sHostPackage != null) {
+                writeHostBrowserToSharedPref(context, sHostPackage);
+            }

[pkotwicz, 2017/05/26 22:38:39]

The Shared Preferences should be cleared if:
1) The user installs a WebAPK from Chrome Canary.
2) User launches WebAPK. SharedPreferences are populated with com.chrome.canary
3) User uninstalls Chrome Canary and installs Chrome Dev
4) User launches WebAPK. SharedPreferences are populated with com.chrome.dev The
browser selection dialog might show.
5) User uninstalls Chrome Dev and installs Chrome Canary.
6) User launches WebAPK. Shared preferences are populated with
com.chrome.canary. The browser selection dialog will not show because the WebAPK
was created for Chrome Canary.

In (6) I would expect deleteSharedPref() to be called. However, it is not
called.

[Xi Han, 2017/05/29 21:18:56]

I moved the call of deleteSharedPref() in getHostBrowserPackageNameInternal() to
above check the metadata, so I believe that will solve this issue. 

         }
-        // Set {@link sHostPackage} to a non-null value so that the value is computed only once.
-        sHostPackage = hostPackage != null ? hostPackage : "";
+
         return sHostPackage;
     }
 
     /**
+     * Returns the package name of the host browser to launch the WebAPK, or null if we did not find
+     * one.
+     */
+    private static String getHostBrowserPackageNameInternal(Context context) {
+        Set<String> installedBrowsers = getInstalledBrowsers(context.getPackageManager());
+        if (installedBrowsers.isEmpty()) {
+            return null;
+        }
+
+        // Gets the package name of the host browser if it is stored in the SharedPreference.
+        String cachedHostBrowser = getHostBrowserFromSharedPreference(context);
+        if (!TextUtils.isEmpty(cachedHostBrowser)
+                && installedBrowsers.contains(cachedHostBrowser)) {
+            return cachedHostBrowser;
+        }
+
+        // Gets the package name of the host browser if it is specified in AndroidManifest.xml.
+        String hostBrowserFromManifest = getHostBrowserFromAndroidManifest(
+                context.getPackageManager(), context.getPackageName());
+        if (!TextUtils.isEmpty(hostBrowserFromManifest)) {
+            if (installedBrowsers.contains(hostBrowserFromManifest)) {
+                return hostBrowserFromManifest;
+            }
+            return null;
+        }
+
+        deleteSharedPref(context);
+
+        // Gets the package name of the default browser on the Android device.
+        // TODO(hanxi): Investigate the best way to know which browser supports WebAPKs.
+        String defaultBrowser = getDefaultBrowserPackageName(context.getPackageManager());
+        if (!TextUtils.isEmpty(defaultBrowser) && installedBrowsers.contains(defaultBrowser)
+                && sBrowsersSupportingWebApk.contains(defaultBrowser)) {
+            return defaultBrowser;
+        }
+
+        return null;
+    }
+
+    /**
+     * Returns a list of browsers to choose host browser from. The list includes all the installed
+     * browsers, and if none of the installed browser supports WebAPKs, Chrome will be added to the
+     * list as well.
+     */
+    public static List<BrowserItem> getBrowserInfosForHostBrowserSelection(
+            PackageManager packageManager) {
+        Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse("http://"));
+        List<ResolveInfo> resolvedActivityList = packageManager.queryIntentActivities(
+                browserIntent, PackageManager.MATCH_DEFAULT_ONLY);
+
+        boolean hasBrowserSupportingWebApks = false;
+        List<BrowserItem> browsers = new ArrayList<>();
+        for (ResolveInfo info : resolvedActivityList) {
+            boolean supportsWebApk = false;
+            if (sBrowsersSupportingWebApk.contains(info.activityInfo.packageName)) {
+                supportsWebApk = true;
+                hasBrowserSupportingWebApks = true;
+            }
+            browsers.add(new BrowserItem(info.activityInfo.packageName,
+                    info.loadLabel(packageManager), info.loadIcon(packageManager), supportsWebApk));
+        }
+
+        if (hasBrowserSupportingWebApks) return browsers;
+
+        // TODO(hanxi): add Chrome's icon to WebAPKs.
+        browsers.add(new BrowserItem("com.android.chrome", "Chrome", null, true));
+        return browsers;
+    }
+
+    /**
      * Returns the uid for the host browser that was specified when building the WebAPK.
      * @param context A context.
      * @return The application uid. Returns -1 on an error.
      */
     public static int getHostBrowserUid(Context context) {
         String hostPackageName = getHostBrowserPackageName(context);
         if (hostPackageName == null) {
             return -1;
         }
         try {
             PackageManager packageManager = context.getPackageManager();
             ApplicationInfo appInfo = packageManager.getApplicationInfo(
                     hostPackageName, PackageManager.GET_META_DATA);
             return appInfo.uid;
         } catch (NameNotFoundException e) {
             e.printStackTrace();
         }
         return -1;
     }
+
+    /** Returns the package name of the host browser cached in the SharedPreferences. */
+    private static String getHostBrowserFromSharedPreference(Context context) {
+        SharedPreferences sharedPref =
+                context.getSharedPreferences(WebApkConstants.PREF_PACKAGE, Context.MODE_PRIVATE);
+        return sharedPref.getString(SHARED_PREF_RUNTIME_HOST, null);
+    }
+
+    /** Returns a set of package names of all the installed browsers on the device. */
+    public static Set<String> getInstalledBrowsers(PackageManager packageManager) {
+        Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse("http://"));
+        List<ResolveInfo> resolvedActivityList = packageManager.queryIntentActivities(
+                browserIntent, PackageManager.MATCH_DEFAULT_ONLY);
+
+        Set<String> packagesSupportingWebApks = new HashSet<String>();
+        for (ResolveInfo info : resolvedActivityList) {
+            packagesSupportingWebApks.add(info.activityInfo.packageName);
+        }
+        return packagesSupportingWebApks;
+    }
+
+    /** Returns the package name of the "runtime host" in the AndroidManifest.xml. */
+    public static String getHostBrowserFromAndroidManifest(
+            PackageManager packageManager, String webApkPackageName) {
+        try {
+            ApplicationInfo ai = packageManager.getApplicationInfo(
+                    webApkPackageName, PackageManager.GET_META_DATA);
+            Bundle bundle = ai.metaData;
+            return bundle.getString(WebApkMetaDataKeys.RUNTIME_HOST);
+        } catch (NameNotFoundException e) {
+            return null;
+        }
+    }
+
+    /** Returns the package name of the default browser on the Android device. */
+    private static String getDefaultBrowserPackageName(PackageManager packageManager) {
+        Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse("http://"));
+        ResolveInfo resolveInfo =
+                packageManager.resolveActivity(browserIntent, PackageManager.MATCH_DEFAULT_ONLY);
+        if (resolveInfo == null || resolveInfo.activityInfo == null) return null;
+
+        return resolveInfo.activityInfo.packageName;
+    }
+
+    /**
+     * Writes the package name of the host browser to the SharedPreferences. If the host browser is
+     * different than the previous one stored, delete the SharedPreference before storing the new
+     * host browser.
+     */
+    public static void writeHostBrowserToSharedPref(Context context, String hostPackage) {
+        if (TextUtils.isEmpty(hostPackage)) return;
+
+        SharedPreferences sharedPref =
+                context.getSharedPreferences(WebApkConstants.PREF_PACKAGE, Context.MODE_PRIVATE);
+        SharedPreferences.Editor editor = sharedPref.edit();
+        editor.putString(SHARED_PREF_RUNTIME_HOST, hostPackage);
+        editor.apply();
+    }
+
+    /** Deletes the SharedPreferences. */
+    private static void deleteSharedPref(Context context) {
+        SharedPreferences sharedPref =
+                context.getSharedPreferences(WebApkConstants.PREF_PACKAGE, Context.MODE_PRIVATE);
+        SharedPreferences.Editor editor = sharedPref.edit();
+        editor.clear();
+        editor.apply();
+    }
 }