Issue #3595 - Add an actual scheduler; use joined threads for file system

src/JsEngine.cpp

 /*
  * 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
  * 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 <AdblockPlus.h>
 #include "GlobalJsObject.h"
 #include "JsContext.h"
 #include "JsError.h"
+#include "Scheduler.h"
 #include "Utils.h"
 
+const AdblockPlus::ImmediateSingleUseThreadType AdblockPlus::ImmediateSingleUseThread = {};
+
+class AdblockPlus::JsEngine::SchedulerImpl
+  : public SchedulerT<SingleUseWorker>
+{
+public:
+  SchedulerImpl() {} // = default;

[sergei, 2017/01/20 13:08:13]

We don't need this line.

+};
+
 namespace
 {
   v8::Handle<v8::Script> CompileScript(v8::Isolate* isolate,
     const std::string& source, const std::string& filename)
   {
     using AdblockPlus::Utils::ToV8String;
     const v8::Handle<v8::String> v8Source = ToV8String(isolate, source);
     if (filename.length())
     {
       const v8::Handle<v8::String> v8Filename = ToV8String(isolate, filename);
@@ skipping 36 matching lines @@
   isolate = v8::Isolate::New();
 }
 
 AdblockPlus::ScopedV8Isolate::~ScopedV8Isolate()
 {
   isolate->Dispose();
   isolate = nullptr;
 }
 
 AdblockPlus::JsEngine::JsEngine(const ScopedV8IsolatePtr& isolate)
-  : isolate(isolate)
-{
-}
+  : isolate(isolate),
+    scheduler(new SchedulerImpl()) // use std::make_unique after we upgrade out of VS2012

[sergei, 2017/01/20 13:08:13]

We don't need this comment about std::make_unique

[Eric, 2017/03/30 17:16:58]

Is that because we're planning never to upgrade from VS2012?

Comments like this allow later code maintenance using `grep`.

[sergei, 2017/04/03 15:35:31]

Maybe, though I think that std::make_shared are much more important than
std::make_unique in general. So, I would rather expect that anyway one will have
to go through the code and simple change all places, including std::make_unique
where it's needed or everywhere.

+{}
 
 AdblockPlus::JsEnginePtr AdblockPlus::JsEngine::New(const AppInfo& appInfo, const ScopedV8IsolatePtr& isolate)
 {
   JsEnginePtr result(new JsEngine(isolate));
 
   const v8::Locker locker(result->GetIsolate());
   const v8::Isolate::Scope isolateScope(result->GetIsolate());
   const v8::HandleScope handleScope(result->GetIsolate());
 
   result->context.reset(new v8::Persistent<v8::Context>(result->GetIsolate(),
@@ skipping 152 matching lines @@
 
 
 void AdblockPlus::JsEngine::SetGlobalProperty(const std::string& name, 
                                               AdblockPlus::JsValuePtr value)
 {
   auto global = GetGlobalObject();
   if (!global)
     throw std::runtime_error("Global object cannot be null");
   global->SetProperty(name, value);
 }
+
+void AdblockPlus::JsEngine::Schedule(std::function<void()> task,
+                                     AdblockPlus::ImmediateSingleUseThreadType)
+{
+  // The present version of the scheduler only does immediate and single-use
+  // It does not, however, detach threads like the legacy thread behavior did.
+  scheduler->Run(task);
+}
+
+void AdblockPlus::JsEngine::WaitForQuietScheduler()
+{
+  scheduler->JoinAll();
+}