The Tor Browser / file revision

 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 package org.mozilla.gecko.sync;

 import android.content.SharedPreferences;

 import android.content.SharedPreferences.Editor;

 public class PrefsBackoffHandler implements BackoffHandler {

   public static final String PREF_EARLIEST_NEXT = "earliestnext";

   private final SharedPreferences prefs;

   private final String prefEarliest;

   public PrefsBackoffHandler(final SharedPreferences prefs, final String prefSuffix) {

     if (prefs == null) {

       throw new IllegalArgumentException("prefs must not be null.");

     }

     this.prefs = prefs;

     this.prefEarliest = PREF_EARLIEST_NEXT + "." + prefSuffix;

   }

   @Override

   public synchronized long getEarliestNextRequest() {

     return prefs.getLong(prefEarliest, 0);

   }

   @Override

   public synchronized void setEarliestNextRequest(final long next) {

     final Editor edit = prefs.edit();

     edit.putLong(prefEarliest, next);

     edit.commit();

   }

   @Override

   public synchronized void extendEarliestNextRequest(final long next) {

     if (prefs.getLong(prefEarliest, 0) >= next) {

       return;

     }

     final Editor edit = prefs.edit();

     edit.putLong(prefEarliest, next);

     edit.commit();

   }

   /**

    * Return the number of milliseconds until we're allowed to touch the server again,

    * or 0 if now is fine.

    */

   @Override

   public long delayMilliseconds() {

     long earliestNextRequest = getEarliestNextRequest();

     if (earliestNextRequest <= 0) {

       return 0;

     }

     long now = System.currentTimeMillis();

     return Math.max(0, earliestNextRequest - now);

   }

 }