Issue 6307 - Introduce external engine created callback

libadblockplus-android/src/org/adblockplus/libadblockplus/android/SingleInstanceEngineProvider.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
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 package org.adblockplus.libadblockplus.android;
 
 import org.adblockplus.libadblockplus.IsAllowedConnectionCallback;
 
 import android.content.Context;
 import android.content.SharedPreferences;
 import android.net.ConnectivityManager;
 import android.util.Log;
 
+import java.util.LinkedList;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.atomic.AtomicInteger;
 
 /**
  * Provides single instance of AdblockEngine shared between registered clients
  */
 public class SingleInstanceEngineProvider implements AdblockEngineProvider
 {
   private static final String TAG = Utils.getTag(SingleInstanceEngineProvider.class);
 
   private Context context;
   private String basePath;
   private boolean developmentBuild;
   private String preloadedPreferenceName;
   private Map<String, Integer> urlToResourceIdMap;
   private AdblockEngine engine;
   private CountDownLatch engineCreated;
   private Long v8IsolateProviderPtr;
-  private Runnable engineCreatedCallback;
-  private Runnable engineDisposedCallback;
+  private List<Runnable> engineCreatedCallbacks = new LinkedList<Runnable>();
+  private List<Runnable> engineDisposedCallbacks = new LinkedList<Runnable>();
 
   /*
     Simple ARC management for AdblockEngine
     Use `retain` and `release`
    */
 
   private AtomicInteger referenceCounter = new AtomicInteger(0);
 
   /**
    * Init with context
@@ skipping 25 matching lines @@
     this.urlToResourceIdMap = urlToResourceIdMap;
     return this;
   }
 
   public SingleInstanceEngineProvider useV8IsolateProvider(long ptr)
   {
     this.v8IsolateProviderPtr = ptr;
     return this;
   }
 
-  public SingleInstanceEngineProvider setEngineCreatedCallback(Runnable callback)
+  public SingleInstanceEngineProvider addEngineCreatedCallback(Runnable callback)
   {
-    this.engineCreatedCallback = callback;
+    this.engineCreatedCallbacks.add(callback);
     return this;
   }
 
-  public SingleInstanceEngineProvider setEngineDisposedCallback(Runnable callback)
+  public void removeEngineCreatedCallback(Runnable callback)

[anton, 2018/01/24 12:51:08]

"remove.." methods are not used anywhere but could be used.
also we could add "clear.." methods too for consistency.
What do you think?

[sergei, 2018/01/24 13:33:02]

I would say if someone wants to remove or clear then just create a new instance
of SingleInstanceEngineProvider and abandon the present one.

[jens, 2018/01/26 08:15:22]

Even if Sergejs idea is also fine I would prefer to be consistent and add a
clear method too.

[anton, 2018/01/26 08:22:58]

Acknowledged.

   {
-    this.engineDisposedCallback = callback;
+    this.engineCreatedCallbacks.remove(callback);
+  }
+
+  public SingleInstanceEngineProvider addEngineDisposedCallback(Runnable callback)
+  {
+    this.engineDisposedCallbacks.add(callback);
     return this;
   }
 
+  public void removeEngineDisposedCallback(Runnable callback)
+  {
+    this.engineDisposedCallbacks.remove(callback);
+  }
+
   private void createAdblock()
   {
     ConnectivityManager connectivityManager =
       (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
     IsAllowedConnectionCallback isAllowedConnectionCallback =
       new IsAllowedConnectionCallbackImpl(connectivityManager);
 
     Log.d(TAG, "Creating adblock engine ...");
 
     AdblockEngine.Builder builder = AdblockEngine
@@ skipping 18 matching lines @@
         context,
         urlToResourceIdMap,
         new AndroidWebRequestResourceWrapper.SharedPrefsStorage(preloadedSubscriptionsPrefs));
     }
 
     engine = builder.build();
 
     Log.d(TAG, "AdblockHelper engine created");
 
     // sometimes we need to init AdblockEngine instance, eg. set user settings
-    if (engineCreatedCallback != null)
+    for (Runnable callback : engineCreatedCallbacks)
     {
-      engineCreatedCallback.run();
+      callback.run();
     }
   }
 
   @Override
   public synchronized boolean retain(boolean asynchronous)
   {
     boolean firstInstance = false;
 
     if (referenceCounter.getAndIncrement() == 0)
     {
@@ skipping 79 matching lines @@
 
   private void disposeAdblock()
   {
     Log.w(TAG, "Disposing adblock engine");
 
     engine.dispose();
     engine = null;
 
     // sometimes we need to deinit something after AdblockEngine instance disposed
     // eg. release user settings
-    if (engineDisposedCallback != null)
+    for (Runnable callback : engineDisposedCallbacks)
     {
-      engineDisposedCallback.run();
+      callback.run();
     }
   }
 
   @Override
   public int getCounter()
   {
     return referenceCounter.get();
   }
 }