Issue 6489 - fix initialization moment of the default scheduler of DefaultPlatformBuilder

src/Platform.cpp

 /*
 * 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 99 matching lines @@
 }
 
 void Platform::WithLogSystem(const WithLogSystemCallback& callback)
 {
   if (logSystem && callback)
     callback(*logSystem);
 }
 
 namespace
 {
-  class SharedAsyncExecutor {
-  public:
-    SharedAsyncExecutor()
-      : executor(new AsyncExecutor())
-    {
-    }
-    void Dispatch(const std::function<void()>& task) {
-      std::lock_guard<std::mutex> lock(asyncExecutorMutex);
-      if (!executor)
-        return;
-      executor->Dispatch(task);
-    }
-    void Invalidate() {
-      std::unique_ptr<AsyncExecutor> tmp;
-      {
-        std::lock_guard<std::mutex> lock(asyncExecutorMutex);
-        tmp = move(executor);
-      }
-    }
-  private:
-    std::mutex asyncExecutorMutex;
-    std::unique_ptr<AsyncExecutor> executor;
-  };
-
   class DefaultPlatform : public Platform
   {
   public:
-    typedef std::shared_ptr<SharedAsyncExecutor> AsyncExecutorPtr;
-    explicit DefaultPlatform(const AsyncExecutorPtr& asyncExecutor, CreationParameters&& creationParams)
+    explicit DefaultPlatform(DefaultPlatformBuilder::AsyncExecutorPtr asyncExecutor, CreationParameters&& creationParams)
       : Platform(std::move(creationParams)), asyncExecutor(asyncExecutor)
     {
     }
     ~DefaultPlatform();
 
     void WithTimer(const WithTimerCallback&) override;
     void WithFileSystem(const WithFileSystemCallback&) override;
     void WithWebRequest(const WithWebRequestCallback&) override;
     void WithLogSystem(const WithLogSystemCallback&) override;
 
   private:
-    AsyncExecutorPtr asyncExecutor;
+    DefaultPlatformBuilder::AsyncExecutorPtr asyncExecutor;
     std::recursive_mutex interfacesMutex;
   };
 
   DefaultPlatform::~DefaultPlatform()
   {
     asyncExecutor->Invalidate();
     LogSystemPtr tmpLogSystem;
     TimerPtr tmpTimer;
     FileSystemPtr tmpFileSystem;
     WebRequestPtr tmpWebRequest;
@@ skipping 24 matching lines @@
     Platform::WithWebRequest(callback);
   }
 
   void DefaultPlatform::WithLogSystem(const WithLogSystemCallback& callback)
   {
     std::lock_guard<std::recursive_mutex> lock(interfacesMutex);
     Platform::WithLogSystem(callback);
   }
 }
 
+DefaultPlatformBuilder::DefaultPlatformBuilder()
+{
+  auto sharedAsyncExecutor = this->sharedAsyncExecutor = std::make_shared<OptionalAsyncExecutor>();
+  defaultScheduler = [sharedAsyncExecutor](const SchedulerTask& task)
+  {
+    sharedAsyncExecutor->Dispatch(task);
+  };
+}
+
 Scheduler DefaultPlatformBuilder::GetDefaultAsyncExecutor()
 {
   return defaultScheduler;
 }
 
 void DefaultPlatformBuilder::CreateDefaultTimer()
 {
   timer.reset(new DefaultTimer());
 }
 
 void DefaultPlatformBuilder::CreateDefaultFileSystem(const std::string& basePath)
 {
   fileSystem.reset(new DefaultFileSystem(GetDefaultAsyncExecutor(), std::unique_ptr<DefaultFileSystemSync>(new DefaultFileSystemSync(basePath))));
 }
 
 void DefaultPlatformBuilder::CreateDefaultWebRequest(std::unique_ptr<IWebRequestSync> webRequest)
 {
   if (!webRequest)
     webRequest.reset(new DefaultWebRequestSync());
   this->webRequest.reset(new DefaultWebRequest(GetDefaultAsyncExecutor(), std::move(webRequest)));
 }
 
 void DefaultPlatformBuilder::CreateDefaultLogSystem()
 {
   logSystem.reset(new DefaultLogSystem());
 }
 
 std::unique_ptr<Platform> DefaultPlatformBuilder::CreatePlatform()
 {
-  auto sharedAsyncExecutor = std::make_shared<SharedAsyncExecutor>();
-  defaultScheduler = [sharedAsyncExecutor](const SchedulerTask& task)
-  {
-    sharedAsyncExecutor->Dispatch(task);
-  };
+  
   if (!logSystem)
     CreateDefaultLogSystem();
   if (!timer)
     CreateDefaultTimer();
   if (!fileSystem)
     CreateDefaultFileSystem();
   if (!webRequest)
     CreateDefaultWebRequest();
 
-  std::unique_ptr<Platform> platform(new DefaultPlatform(sharedAsyncExecutor, std::move(*this)));
+  std::unique_ptr<Platform> platform(new DefaultPlatform(std::move(sharedAsyncExecutor), std::move(*this)));
   return platform;
 }