Issue 3595 - Get rid of detached threads for setTimeout

include/AdblockPlus/ITimer.h

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2017 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/>.
  */
 
-#ifndef ADBLOCK_PLUS_LOG_SYSTEM_H
-#define ADBLOCK_PLUS_LOG_SYSTEM_H
+#ifndef ADBLOCK_PLUS_TIMER_H
+#define ADBLOCK_PLUS_TIMER_H
 
-#include <string>
+#include <functional>
+#include <chrono>
 #include <memory>
 
 namespace AdblockPlus
 {
   /**
-   * Logging interface.
+   * Timer manager interface.
    */
-  class LogSystem
+  struct ITimer
   {
-  public:
     /**
-     * Log level.
-     */
-    enum LogLevel {LOG_LEVEL_TRACE, LOG_LEVEL_LOG, LOG_LEVEL_INFO, LOG_LEVEL_WARN, LOG_LEVEL_ERROR};
-
-    virtual ~LogSystem() {}
+    * Callback type invoked after elapsing of timer timeout.
+    */
+    typedef std::function<void()> TimerCallback;
+    virtual ~ITimer() {};
 
     /**
-     * Writes a log message.
-     * @param logLevel Log level.
-     * @param message Log message.
-     * @param source Source of the message, e.g. file name and line.
-     *        Ignored when empty.
+     * Sets a timer.
+     * @param timeout A timer callback will be called after that interval.
+     * @param timeCallback The callback which is called after timeout.
      */
-    virtual void operator()(LogLevel logLevel, const std::string& message,
-          const std::string& source) = 0;
+    virtual void SetTimer(const std::chrono::milliseconds& timeout, const TimerCallback& timerCallback) = 0;
   };
 
   /**
-   * Shared smart pointer to a `LogSystem` instance.
+   * Unique smart pointer to an instance of `ITimer` implementation.
    */
-  typedef std::shared_ptr<LogSystem> LogSystemPtr;
+  typedef std::unique_ptr<ITimer> TimerPtr;
 }
 
 #endif