Issue 4692 - Dont' keep a strong reference from timer thread

include/AdblockPlus/JsEngine.h

 /*
  * 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 64 matching lines @@
    */
   typedef std::shared_ptr<ScopedV8Isolate> ScopedV8IsolatePtr;
 
   /**
    * JavaScript engine used by `FilterEngine`, wraps v8.
    */
   class JsEngine : public std::enable_shared_from_this<JsEngine>
   {
     friend class JsValue;
     friend class JsContext;
+
   public:
     /**
      * Event callback function.
      */
     typedef std::function<void(JsValueList& params)> EventCallback;
 
     /**
     * Callback function returning false when current connection is not allowed
     * e.g. because it is a metered connection.
     */
@@ skipping 173 matching lines @@
     v8::Isolate* GetIsolate()
     {
       return isolate->Get();
     }
 
     // Private functionality required to implement timers.
     struct TimerTaskInfo
     {
       ~TimerTaskInfo();
       int delay;
       std::vector<std::unique_ptr<v8::Persistent<v8::Value>>> arguments;

[sergei, 2017/03/23 17:27:13]

We need std::unique_ptr here because v8::Persistent from currently used version
of v8 does not support move semantics.

     };
     typedef std::list<TimerTaskInfo> TimerTaskInfos;
     struct TimerTask
     {
       std::weak_ptr<JsEngine> weakJsEngine;
-      TimerTaskInfos::const_iterator ii_taskInfo;

[Oleksandr, 2017/03/24 12:15:25]

Nit: It is not immediately clear to me what ii_ stands for. How about
taskInfoIterator?

[sergei, 2017/03/24 12:34:39]

Done.

+      TimerTaskInfos::const_iterator taskInfoIterator;
     };
     TimerTask CreateTimerTask(const v8::Arguments& arguments);
-    void CallTimerTask(TimerTaskInfos::const_iterator ii_taskInfo);
+    void CallTimerTask(TimerTaskInfos::const_iterator taskInfoIterator);
   private:
     explicit JsEngine(const ScopedV8IsolatePtr& isolate);
 
     JsValuePtr GetGlobalObject();
 
     /// Isolate must be disposed only after disposing of all objects which are
     /// using it.
     ScopedV8IsolatePtr isolate;
 
     FileSystemPtr fileSystem;
     WebRequestPtr webRequest;
     LogSystemPtr logSystem;
     std::unique_ptr<v8::Persistent<v8::Context>> context;
     EventMap eventCallbacks;
     std::mutex eventCallbacksMutex;
     std::mutex isConnectionAllowedMutex;
     IsConnectionAllowedCallback isConnectionAllowed;
     TimerTaskInfos timerTaskInfos;
   };
 }
 
 #endif