Issue 6265 - Create shared AdblockEngine instance in AdblockWebView in background

libadblockplus-android-webviewapp/src/org/adblockplus/libadblockplus/android/webviewapp/SettingsActivity.java

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 25 matching lines @@
     BaseSettingsFragment.Provider,
     GeneralSettingsFragment.Listener,
     WhitelistedDomainsSettingsFragment.Listener
 {
   private static final String TAG = Utils.getTag(SettingsActivity.class);
 
   @Override
   protected void onCreate(Bundle savedInstanceState)
   {
     super.onCreate(savedInstanceState);
-    AdblockHelper.get().retain(MainActivity.ADBLOCKENGINE_RETAIN_ASYNC);

[sergei, 2018/01/19 13:56:41]

I'm not sure that changing from ADBLOCKENGINE_RETAIN_ASYNC to Boolean true is
better.

[anton, 2018/01/22 06:17:37]

What do you mean "better"?
Previously we had this flag to adjust is it should be done async or synch. Since
now it's up to  AdblockWebView and it does it in async way (no choice) we don't
have this setting.

We could invoke it sync here or async + waitForReady - does not make sense (it
just affects the code line when it's locked).
In practice since we create AdblockEngine in MainActivity we don't create new
instance of FilterEngine but just inc/dec the counter.

+
+    // retaining AdblockEngine asynchronously
+    AdblockHelper.get().getProvider().retain(true);
 
     insertGeneralFragment();
   }
 
   private void insertGeneralFragment()
   {
     getFragmentManager()
       .beginTransaction()
       .replace(
         android.R.id.content,
@@ skipping 11 matching lines @@
       .addToBackStack(WhitelistedDomainsSettingsFragment.class.getSimpleName())
       .commit();
   }
 
   // provider
 
   @Override
   public AdblockEngine getAdblockEngine()
   {
     // if it's retained asynchronously we have to wait until it's ready
-    AdblockHelper.get().waitForReady();
-    return AdblockHelper.get().getEngine();
+    AdblockHelper.get().getProvider().waitForReady();
+    return AdblockHelper.get().getProvider().getEngine();
   }
 
   @Override
   public AdblockSettingsStorage getAdblockSettingsStorage()
   {
     return AdblockHelper.get().getStorage();
   }
 
   // listener
 
@@ skipping 15 matching lines @@
                                AdblockSettings settings)
   {
     // show error here if domain is invalid
     return domain != null && domain.length() > 0;
   }
 
   @Override
   protected void onDestroy()
   {
     super.onDestroy();
-    AdblockHelper.get().release();
+    AdblockHelper.get().getProvider().release();
   }
 }