Issue 5237 - Correct filter lists not applied on other language installation

adblockplussbrowser/src/org/adblockplus/sbrowser/contentblocker/util/SubscriptionUtils.java

Index: adblockplussbrowser/src/org/adblockplus/sbrowser/contentblocker/util/SubscriptionUtils.java
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new file mode 100644
--- /dev/null
+++ b/adblockplussbrowser/src/org/adblockplus/sbrowser/contentblocker/util/SubscriptionUtils.java
@@ -0,0 +1,91 @@
+/*
+ * 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
+ * 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.sbrowser.contentblocker.util;
+
+import java.util.List;
+import java.util.Locale;
+
+import org.adblockplus.sbrowser.contentblocker.engine.DefaultSubscriptionInfo;
+import org.adblockplus.sbrowser.contentblocker.engine.Engine;
+
+import android.content.res.Resources;
+
+public class SubscriptionUtils
+{
+
+  private static final String INDONESIAN_OLD = "in";
+  private static final String INDONESIAN_NEW = "id";
+  private static final String HEBREW_OLD = "iw";
+  private static final String HEBREW_NEW = "he";
+  private static final String YIDDISH_OLD = "ji";
+  private static final String YIDDISH_NEW = "yi";
+
+  /**
+   * @param defaultSubscriptions
+   * @return The URL of the filter list which fits best for the device language.
+   * If no match was found, return EASYLIST as default.
+   */
+  public static String chooseDefaultSubscriptionUrl(List<DefaultSubscriptionInfo> defaultSubscriptions)
+  {
+    for (final DefaultSubscriptionInfo info : defaultSubscriptions)
+    {
+      if (info != null && info.getPrefixes().contains(getDeviceLanguageCode()) && info.isComplete())
+      {
+        return info.getUrl();
+      }
+    }
+    return Engine.EASYLIST_URL;
+  }
+
+  @SuppressWarnings("deprecation")
+  private static String getDeviceLanguageCode()
+  {
+    Locale locale;
+    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.N)
+    {
+      locale = Resources.getSystem().getConfiguration().getLocales().get(0);
+    }
+    else
+    {
+      locale = Resources.getSystem().getConfiguration().locale;
+    }
+
+    return convertOldISOCodes(locale.getLanguage());
+  }
+
+  /*
+   * ISO 639 is not a stable standard; some of the language codes it defines
+   * (specifically "iw", "ji", and "in") have changed. Android returns the old codes
+   * ("iw", "ji", and "in") but in subscriptions.xml we use the new codes ("he", "yi", and "id").
+   * To match the device language to a subscription, we need to convert the old codes.
+   */
+  private static String convertOldISOCodes(String language)
+  {
+    switch (language)
+    {
+      case HEBREW_OLD:
+        return HEBREW_NEW;
+      case YIDDISH_OLD:
+        return YIDDISH_NEW;
+      case INDONESIAN_OLD:
+        return INDONESIAN_NEW;
+      default:
+        return language;
+    }
+  }
+}