WebAPK: Move MainActivity#onCreate() to runtime library

chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/HostBrowserClassLoader.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.app.Service;
 import android.content.Context;
-import android.content.Intent;
 import android.content.SharedPreferences;
 import android.content.pm.PackageInfo;
 import android.content.pm.PackageManager;
-import android.os.Bundle;
-import android.os.IBinder;
 import android.util.Log;
 
 import org.chromium.webapk.lib.common.WebApkUtils;
 
 import java.io.File;
-import java.lang.reflect.Constructor;
 import java.util.Scanner;
 
 /**
- * Shell class for services provided by WebAPK to Chrome. Extracts code with implementation of
- * services from .dex file in Chrome APK.
+ * Creates ClassLoader for WebAPK-specific dex file in Chrome APK's assets.
  */
-public class WebApkServiceFactory extends Service {
-    private static final String TAG = "cr_WebApkServiceFactory";
-
-    /**
-     * Name of the class with IBinder API implementation.
-     */
-    private static final String WEBAPK_SERVICE_IMPL_CLASS_NAME =
-            "org.chromium.webapk.lib.runtime_library.WebApkServiceImpl";
+public class HostBrowserClassLoader {
+    private static final String TAG = "cr_HostBrowserClassLoader";
 
     /**
      * Name of the shared preferences file.
      */
     private static final String PREF_PACKAGE = "org.chromium.webapk.shell_apk";
 
     /**
      * Name of the shared preference for Chrome's version code.
      */
     private static final String REMOTE_VERSION_CODE_PREF =
             "org.chromium.webapk.shell_apk.version_code";
 
     /**
      * Name of the shared preference for the version number of the dynamically loaded dex.
      */
     private static final String RUNTIME_DEX_VERSION_PREF =
             "org.chromium.webapk.shell_apk.dex_version";
 
-    /**
-     * Key for passing id of icon to represent WebAPK notifications in status bar.
-     */
-    private static final String KEY_SMALL_ICON_ID = "small_icon_id";
-
-    /**
-     * Key for passing package name of only process allowed to call the service's methods.
-     */
-    private static final String KEY_HOST_BROWSER_PACKAGE = "host_browser_package";
-
     /*
-     * ClassLoader for loading {@link WEBAPK_SERVICE_IMPL_CLASS_NAME}. Static so that all
-     * {@link WebApkServiceFactory} service instatiations use the same ClassLoader during the app's
-     * lifetime.
+     * ClassLoader for WebAPK dex. Static so that the same ClassLoader is used for app's lifetime.
      */
     private static ClassLoader sClassLoader;
 
-    @Override
-    public IBinder onBind(Intent intent) {
-        ClassLoader webApkClassLoader = getClassLoaderInstance(this);
-        if (webApkClassLoader == null) {
-            Log.w(TAG, "Unable to create ClassLoader.");
-            return null;
-        }
-
-        try {
-            Class<?> webApkServiceImplClass =
-                    webApkClassLoader.loadClass(WEBAPK_SERVICE_IMPL_CLASS_NAME);
-            Constructor<?> webApkServiceImplConstructor =
-                    webApkServiceImplClass.getConstructor(Context.class, Bundle.class);
-            String hostPackageName = WebApkUtils.getHostBrowserPackageName(this);
-            Bundle bundle = new Bundle();
-            bundle.putInt(KEY_SMALL_ICON_ID, R.drawable.app_icon);
-            bundle.putString(KEY_HOST_BROWSER_PACKAGE, hostPackageName);
-            return (IBinder) webApkServiceImplConstructor.newInstance(new Object[] {this, bundle});
-        } catch (Exception e) {
-            Log.w(TAG, "Unable to create WebApkServiceImpl.");
-            e.printStackTrace();
-            return null;
-        }
-    }
+    /**
+     * Guards all access to {@link sClassLoader}.
+     */
+    private static final Object sLock = new Object();
 
     /**
-     * Gets / creates ClassLoader for loading {@link WEBAPK_SERVICE_IMPL_CLASS_NAME}.
+     * Gets / creates ClassLoader for WebAPK dex.
      * @param context WebAPK's context.
+     * @param canaryClassname Class to load to check that ClassLoader is valid.
      * @return The ClassLoader.
      */
-    private static ClassLoader getClassLoaderInstance(Context context) {
-        if (sClassLoader == null) {
-            sClassLoader = createClassLoader(context);
+    public static ClassLoader getClassLoaderInstance(Context context, String canaryClassName) {
+        synchronized (sLock) {
+            if (sClassLoader == null) {
+                sClassLoader = createClassLoader(context, canaryClassName);
+            }
         }
         return sClassLoader;
     }
 
     /**
-     * Creates ClassLoader for loading {@link WEBAPK_SERVICE_IMPL_CLASS_NAME}.
+     * Creates ClassLoader for WebAPK dex.
      * @param context WebAPK's context.
+     * @param canaryClassName Class to load to check that ClassLoader is valid.
      * @return The ClassLoader.
      */
-    private static ClassLoader createClassLoader(Context context) {
+    private static ClassLoader createClassLoader(Context context, String canaryClassName) {
         Context remoteContext = WebApkUtils.getHostBrowserContext(context);
         if (remoteContext == null) {
             Log.w(TAG, "Failed to get remote context.");
             return null;
         }
 
-        SharedPreferences preferences = context.getSharedPreferences(PREF_PACKAGE, MODE_PRIVATE);
+        SharedPreferences preferences =
+                context.getSharedPreferences(PREF_PACKAGE, Context.MODE_PRIVATE);
 
         int runtimeDexVersion = preferences.getInt(RUNTIME_DEX_VERSION_PREF, -1);
         int newRuntimeDexVersion = checkForNewRuntimeDexVersion(preferences, remoteContext);
         if (newRuntimeDexVersion == -1) {
             newRuntimeDexVersion = runtimeDexVersion;
         }
         File localDexDir = context.getDir("dex", Context.MODE_PRIVATE);
         if (newRuntimeDexVersion != runtimeDexVersion) {
             Log.w(TAG, "Delete cached dex files.");
             DexLoader.deleteCachedDexes(localDexDir);
         }
 
         String dexAssetName = WebApkUtils.getRuntimeDexName(newRuntimeDexVersion);
         File remoteDexFile =
                 new File(remoteContext.getDir("dex", Context.MODE_PRIVATE), dexAssetName);
-        return DexLoader.load(remoteContext, dexAssetName, WEBAPK_SERVICE_IMPL_CLASS_NAME,
+        return DexLoader.load(remoteContext, dexAssetName, canaryClassName,
                 remoteDexFile, localDexDir);
     }
 
     /**
      * Checks if there is a new "runtime dex" version number. If there is a new version number,
      * updates SharedPreferences.
      * @param preferences WebAPK's SharedPreferences.
      * @param remoteContext
      * @return The new "runtime dex" version number. -1 if there is no new version number.
      */
@@ skipping 42 matching lines @@
             if (scanner != null) {
                 try {
                     scanner.close();
                 } catch (Exception e) {
                 }
             }
         }
         return value;
     }
 }