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 24 matching lines @@
 {
   private static final String TAG = Utils.getTag(AdblockHelper.class);
 
   /**
    * Suggested preference name
    */
   public static final String PREFERENCE_NAME = "ADBLOCK";
   private static AdblockHelper _instance;
 
   private Context context;
+  private String basePath;
   private boolean developmentBuild;
   private String preferenceName;
   private AdblockEngine engine;
   private AdblockSettingsStorage storage;
   private CountDownLatch engineCreated;
 
   /*
     Simple ARC management for AdblockEngine
     Use `retain` and `release`
    */
@@ skipping 26 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, boolean developmentBuild, String preferenceName)
+  public void init(Context context, String basePath, boolean developmentBuild, String preferenceName)
   {
     this.context = context.getApplicationContext();
+    this.basePath = basePath;
     this.developmentBuild = developmentBuild;
     this.preferenceName = preferenceName;
   }
 
   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);
 
     // latch is required for async (see `waitForReady()`)
     engineCreated = new CountDownLatch(1);
 
     engine = AdblockEngine.create(
       AdblockEngine.generateAppInfo(context, developmentBuild),
-      context.getCacheDir().getAbsolutePath(),
-      true); // `true` as we need element hiding
+      basePath, true); // `true` as we need element hiding
     Log.d(TAG, "AdblockHelper engine created");
 
     AdblockSettings settings = storage.load();
     if (settings != null)
     {
       Log.d(TAG, "Applying saved adblock settings to adblock engine");
       // apply last saved settings to adblock engine
 
       // all the settings except `enabled` and whitelisted domains are saved by adblock engine itself
       engine.setEnabled(settings.isAdblockEnabled());
@@ skipping 87 matching lines @@
    */
   public synchronized void release()
   {
     if (referenceCounter.decrementAndGet() == 0)
     {
       waitForReady();
       disposeAdblock();
     }
   }
 }