Issue 4938 - fix race conditions related to LazyFileSystem

test/BaseJsTest.cpp

 /*
 * 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/>.
 */
 
 #include "BaseJsTest.h"
+#include <AdblockPlus/FilterEngine.h>
+
+using namespace AdblockPlus;
 
 void DelayedTimer::ProcessImmediateTimers(DelayedTimer::SharedTasks& timerTasks)
 {
   auto ii = timerTasks->begin();
   while (ii != timerTasks->end())
   {
     if (ii->timeout.count() == 0)
     {
       ii->callback();
       ii = timerTasks->erase(ii);
@@ skipping 13 matching lines @@
 
 AdblockPlus::JsEnginePtr CreateJsEngine(JsEngineCreationParameters&& jsEngineCreationParameters)
 {
   auto jsEngine = AdblockPlus::JsEngine::New(jsEngineCreationParameters.appInfo,
     std::move(jsEngineCreationParameters.timer),
     std::move(jsEngineCreationParameters.fileSystem),
     std::move(jsEngineCreationParameters.webRequest),
     std::move(jsEngineCreationParameters.logSystem));
   return jsEngine;
 }
+
+FilterEnginePtr CreateFilterEngine(LazyFileSystem& fileSystem,
+  const JsEnginePtr& jsEngine,
+  const FilterEngine::CreationParameters& creationParams)
+{
+  std::list<LazyFileSystem::Task> fileSystemTasks;
+  fileSystem.scheduler = [&fileSystemTasks](const LazyFileSystem::Task& task)
+  {
+    fileSystemTasks.emplace_back(task);
+  };
+  FilterEnginePtr retValue;
+  FilterEngine::CreateAsync(jsEngine, [&retValue, &fileSystem](const FilterEnginePtr& filterEngine)
+  {
+    retValue = filterEngine;
+    fileSystem.scheduler = LazyFileSystem::ExecuteImmediately;
+  }, creationParams);
+  while (!retValue && !fileSystemTasks.empty())
+  {
+    (*fileSystemTasks.begin())();
+    fileSystemTasks.pop_front();
+  }
+  return retValue;
+}