Issue 4903 - Allow to specify file system root

libadblockplus-android-settings/src/org/adblockplus/libadblockplus/android/settings/AdblockHelper.java

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 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 72 matching lines @@
 
   public AdblockSettingsStorage getStorage()
   {
     return storage;
   }
 
   /**
    * Init with context
    * @param context application context
    * @param basePath file system root to store files
+   *
+   *                 Adblock Plus library will download subscription files and store them on
+   *                 the path passed. The path should exist and the directory content should not be
+   *                 cleared out occasionally. Using `context.getCacheDir().getAbsolutePath()` is not
+   *                 recommended because it can be cleared by the system.
    * @param developmentBuild debug or release?
    * @param preferenceName Shared Preferences name
    */
   public void init(Context context, String basePath, boolean developmentBuild, String preferenceName)
   {
     this.context = context.getApplicationContext();
     this.basePath = basePath;
     this.developmentBuild = developmentBuild;
     this.preferenceName = preferenceName;
-  }
-
-  /**
-   * Init with context
-   * @param context application context
-   * @param developmentBuild debug or release?
-   * @param preferenceName Shared Preferences name
-   */
-  public void init(Context context, boolean developmentBuild, String preferenceName)
-  {
-    init(context, context.getCacheDir().getAbsolutePath(), developmentBuild, preferenceName);

[diegocarloslima, 2017/03/13 13:58:11]

As you already pointed, it would be better to use getFilesDir() here, since the
cache can be cleared out by the system

[anton, 2017/03/14 04:15:26]

Well, i'd prefer to remove it at all or leave as-is because of
back-compatibility.
I don't see any reason for any app "default" directories (like getCacheDir() or
getFilesDir()) to be the only suitable and reasonable directory for the files so
i believe the user should make the decision himself.

[diegocarloslima, 2017/03/16 19:55:23]

I'm not against removing it, but if we decide to keep it, I would vote for
changing it, because we want to provide the best blocking experience possible,
and storing on cache directory which could be cleared by the system, can
compromise that

   }
 
   private void createAdblock()
   {
     Log.d(TAG, "Creating adblock engine ...");
 
     // read and apply current settings
     SharedPreferences prefs = context.getSharedPreferences(preferenceName, Context.MODE_PRIVATE);
     storage = new SharedPrefsStorage(prefs);
 
@@ skipping 103 matching lines @@
    */
   public synchronized void release()
   {
     if (referenceCounter.decrementAndGet() == 0)
     {
       waitForReady();
       disposeAdblock();
     }
   }
 }