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.net.Uri;
+import android.os.AsyncTask;
 import android.os.Bundle;
+import android.text.TextUtils;
 
 import org.chromium.webapk.lib.common.WebApkMetaDataKeys;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
 /**
  * Contains utility methods for interacting with WebAPKs.
  */
 public class WebApkUtils {
+    private static final String SHARED_PREF = "metadata";
+    private static final String SHARED_PREF_RUNTIME_HOST = "runtime_host";
+    private static final String CHROME_STABLE_PACKAGE = "com.android.chrome";
+    private static final String CHROME_BETA_PACKAGE = "com.chrome.beta";
+    private static final String CHROME_DEV_PACKAGE = "com.chrome.dev";
+    private static final String CHROME_CANARY_PACKAGE = "com.chrome.canary";

[pkotwicz, 2017/05/09 21:38:28]

Personally, I would inline the package names in |sBrowsersSupportingWebApk| and
remove the constants

[Yaron, 2017/05/10 17:47:57]

+1

[Xi Han, 2017/05/10 18:27:25]

Done.

 
-    /**
-     * Caches the value read from Application Metadata which specifies the host browser's package
-     * name.
-     */
+    // The package names of different versions of Chromes that support WebAPKs.
+    private static final List<String> sBrowsersSupportingWwebApk;

[pkotwicz, 2017/05/09 21:38:27]

Nit: sBrowsersSupportingWwebApk -> sBrowsersSupportingWebApk

[Xi Han, 2017/05/10 18:27:25]

Done.

+
+    static {
+        sBrowsersSupportingWwebApk = new ArrayList<String>(Arrays.asList(CHROME_STABLE_PACKAGE,
+                CHROME_BETA_PACKAGE, CHROME_DEV_PACKAGE, CHROME_CANARY_PACKAGE));
+    }
+
+    /** Caches the package name of the host browser. */
     private static String sHostPackage;
 
     /**
      * 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.
      * @param context A context.
      * @return The package name. Returns null on an error.
      */
-    public static String getHostBrowserPackageName(Context context) {
+    public static String getHostBrowserPackageName(final 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();
+        // Gets the package name of the host browser if it is specified in AndroidManifest.xml.
+        String hostBrowserFromManifest = getHostBrowserFromAndroidManifest(context);
+
+        // Gets all installed browsers that support WebAPKs.
+        List<String> packagesSupportingWebApks =
+                getInstalledBrowsersSupportingWebApks(context.getPackageManager());
+
+        if (packagesSupportingWebApks.isEmpty()) {
+            hostPackage = null;

[Yaron, 2017/05/10 17:47:57]

hostPackage is already null and just a local variable.

[Xi Han, 2017/05/10 18:27:25]

Acknowledged.

+        } else if (!TextUtils.isEmpty(hostBrowserFromManifest)
+                && packagesSupportingWebApks.contains(hostBrowserFromManifest)) {
+            hostPackage = hostBrowserFromManifest;
+        } else {
+            // Gets the package name of the host browser if it is stored in the SharedPreference.
+            String cachedHostBrowser = getHostBrowserFromSharedPreference(context);
+            if (!TextUtils.isEmpty(cachedHostBrowser)
+                    && packagesSupportingWebApks.contains(cachedHostBrowser)) {
+                hostPackage = cachedHostBrowser;
+            } else {
+                // Gets the package name of the default browser on the Android device.
+                // TODO(hanxi): adds a new dialog to ask users to select a host browser when the
+                // default browser doesn't support WebAPKs.
+                String defaultBrowser = getDefaultBrowserPackageName(context.getPackageManager());
+                if (!TextUtils.isEmpty(defaultBrowser)
+                        && packagesSupportingWebApks.contains(defaultBrowser)) {
+                    hostPackage = defaultBrowser;

[pkotwicz, 2017/05/09 21:38:27]

Can you change lines 99-107 into iterating over a for() loop? (Iterating over
sBrowsersSupportingWebApk). This means that sBrowsersSupportingWebApk would need
to be sorted with the most preferred browser first.

[Xi Han, 2017/05/10 18:27:25]

Good idea, thanks!

+                } else if (packagesSupportingWebApks.contains(CHROME_STABLE_PACKAGE)) {
+                    hostPackage = CHROME_STABLE_PACKAGE;
+                } else if (packagesSupportingWebApks.contains(CHROME_BETA_PACKAGE)) {
+                    hostPackage = CHROME_BETA_PACKAGE;
+                } else if (packagesSupportingWebApks.contains(CHROME_DEV_PACKAGE)) {
+                    hostPackage = CHROME_DEV_PACKAGE;
+                } else if (packagesSupportingWebApks.contains(CHROME_CANARY_PACKAGE)) {
+                    hostPackage = CHROME_CANARY_PACKAGE;
+                }
+            }
         }
+
         // Set {@link sHostPackage} to a non-null value so that the value is computed only once.
         sHostPackage = hostPackage != null ? hostPackage : "";
+        writeHostBrowserToSharedPref(context, sHostPackage);
         return sHostPackage;
     }
 
     /**
      * 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(SHARED_PREF, Context.MODE_PRIVATE);
+        return sharedPref.getString(SHARED_PREF_RUNTIME_HOST, null);
+    }
+
+    /**
+     * Returns all of the installed browsers that supports WebAPKs.
+     * TODO(hanxi): Investigate the best way to know which browser supports WebAPKs.
+     */
+    private static List<String> getInstalledBrowsersSupportingWebApks(
+            PackageManager packageManager) {

[pkotwicz, 2017/05/09 21:38:27]

I don't know what to think about this function.

In the context of lines 99 - 107 I want this function to return a "sorted list
with the most preferred browser first".

In the context of lines 82 and 89 I want this function to return a "list of
installed browsers"

[Xi Han, 2017/05/10 18:27:25]

How about changing the variable |packagesSupportingWebApks| to
|installedBrowsersSupportingWebApks|? This function is most likely to be changed
when implementing the host browser selection dialog.

+        Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse("http://"));
+        List<ResolveInfo> resolvedActivityList = packageManager.queryIntentActivities(
+                browserIntent, PackageManager.MATCH_DEFAULT_ONLY);
+
+        List<String> packagesSupportingWebApks = new ArrayList<>();
+        for (ResolveInfo info : resolvedActivityList) {
+            if (sBrowsersSupportingWwebApk.contains(info.activityInfo.packageName)) {
+                packagesSupportingWebApks.add(info.activityInfo.packageName);
+            }
+        }
+        return packagesSupportingWebApks;
+    }
+
+    /** Returns the package name of the "runtime host" in the AndroidManifest.xml. */
+    private static String getHostBrowserFromAndroidManifest(Context context) {

[pkotwicz, 2017/05/09 21:38:28]

Should this function take a PackageManager as an argument for the sake of
consistency?

[Xi Han, 2017/05/10 18:27:25]

Done.

+        try {
+            ApplicationInfo ai = context.getPackageManager().getApplicationInfo(
+                    context.getPackageName(), PackageManager.GET_META_DATA);
+            Bundle bundle = ai.metaData;
+            return bundle.getString(WebApkMetaDataKeys.RUNTIME_HOST);
+        } catch (NameNotFoundException e) {
+            e.printStackTrace();

[pkotwicz, 2017/05/09 21:38:27]

We probably remove e.printStackTrace() (I know that you copied it from the old
code)

[Xi Han, 2017/05/10 18:27:25]

Done.

+            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 SharedPreferences. */
+    private static void writeHostBrowserToSharedPref(
+            final Context context, final String hostPackage) {
+        if (TextUtils.isEmpty(hostPackage)) return;
+
+        new AsyncTask<String, Void, Void>() {
+            @Override
+            protected Void doInBackground(String... params) {
+                SharedPreferences sharedPref =
+                        context.getSharedPreferences(SHARED_PREF, Context.MODE_PRIVATE);
+                SharedPreferences.Editor editor = sharedPref.edit();
+                editor.putString(SHARED_PREF_RUNTIME_HOST, params[0]);
+                editor.apply();
+                return null;
+            }
+        }.execute(hostPackage);

[pkotwicz, 2017/05/09 21:38:27]

Is it worth to save to SharedPreferences in an AsyncTask?
- How long does saving to SharedPreferences take?
- How long do the PackageManager requests in
getInstalledBrowsersSupportingWebApks() take?

According to the documentation SharedPreferences.Editor#apply() is somewhat
asynchronous

[Yaron, 2017/05/10 17:47:57]

Ya, it's not necessary for apply

[Xi Han, 2017/05/10 18:27:25]

Ok, removed.

+    }
 }