Issue 5570 - Make V8 isolate injectable into JsEngine

include/AdblockPlus/JsEngine.h

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present 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 35 matching lines @@
 {
   class JsEngine;
   class Platform;
 
   /**
    * Shared smart pointer to a `JsEngine` instance.
    */
   typedef std::shared_ptr<JsEngine> JsEnginePtr;
 
   /**
-   * Scope based isolate manager. Creates a new isolate instance on
-   * constructing and disposes it on destructing.
+   * Provides with isolate. The main aim of this iterface is to delegate a
+   * proper initialization and deinitialization of v8::Isolate to an embedder.
    */
-  class ScopedV8Isolate
+  struct IV8IsolateProvider
   {
-  public:
-    ScopedV8Isolate();
-    ~ScopedV8Isolate();
-    v8::Isolate* Get()
-    {
-      return isolate;
-    }
-  private:
-    ScopedV8Isolate(const ScopedV8Isolate&);
-    ScopedV8Isolate& operator=(const ScopedV8Isolate&);
+    virtual ~IV8IsolateProvider() {}
 
-    v8::Isolate* isolate;
+    /**
+     * Returns v8::Isolate. All subsequent calls of this method should return
+     * the same pointer to v8::Isolate as the first call.
+     */
+    virtual v8::Isolate* Get() = 0;
   };
 
   /**
    * JavaScript engine used by `FilterEngine`, wraps v8.
    */
   class JsEngine : public std::enable_shared_from_this<JsEngine>
   {
     friend class JsValue;
     friend class JsContext;
 
@@ skipping 22 matching lines @@
       friend class JsEngine;
       JsWeakValuesLists::const_iterator iterator;
     };
 
     /**
      * Creates a new JavaScript engine instance.
      *
      * @param appInfo Information about the app.
      * @param platform AdblockPlus platform providing with necessary
      *        dependencies.
+     * @param isolate A provider of v8::Isolate, if the value is nullptr then
+     *        a default implementation is used.
      * @return New `JsEngine` instance.
      */
-    static JsEnginePtr New(const AppInfo& appInfo, Platform& platform);
+    static JsEnginePtr New(const AppInfo& appInfo, Platform& platform, std::unique_ptr<IV8IsolateProvider> isolate = nullptr);
     /**
      * Registers the callback function for an event.
      * @param eventName Event name. Note that this can be any string - it's a
      *        general purpose event handling mechanism.
      * @param callback Event callback function.
      */
     void SetEventCallback(const std::string& eventName, const EventCallback& callback);
 
     /**
      * Removes the callback function for an event.
@@ skipping 120 matching lines @@
      * @param name Name of the property to set.
      * @param value Value of the property to set.
      */
     void SetGlobalProperty(const std::string& name, const AdblockPlus::JsValue& value);
 
     /**
      * Returns a pointer to associated v8::Isolate.
      */
     v8::Isolate* GetIsolate()
     {
-      return isolate.Get();
+      return isolate->Get();
     }
 
     /**
      * Notifies JS engine about critically low memory what should cause a
      * garbage collection.
      */
     void NotifyLowMemory();
 
     /**
      * Private functionality.
      */
     Platform& GetPlatform()
     {
       return platform;
     }
   private:
     void CallTimerTask(const JsWeakValuesID& timerParamsID);
 
-    explicit JsEngine(Platform& platform);
+    explicit JsEngine(Platform& platform, std::unique_ptr<IV8IsolateProvider> isolate);
 
     JsValue GetGlobalObject();
 
+    Platform& platform;
     /// Isolate must be disposed only after disposing of all objects which are
     /// using it.
-    ScopedV8Isolate isolate;
-    Platform& platform;
+    std::unique_ptr<IV8IsolateProvider> isolate;
 
     std::unique_ptr<v8::Global<v8::Context>> context;
     EventMap eventCallbacks;
     std::mutex eventCallbacksMutex;
     JsWeakValuesLists jsWeakValuesLists;
     std::mutex jsWeakValuesListsMutex;
   };
 }
 
 #endif