Remove the pointless CreateInThread method from BackgroundThread and instead move objects to the right thread after creation.

src/core/backgroundthread.cpp

@@ -16,41 +16,13 @@
 
 #include "backgroundthread.h"
 
-int BackgroundThreadBase::CreateInThreadEvent::sEventType = -1;
-
 BackgroundThreadBase::BackgroundThreadBase(QObject *parent)
   : QThread(parent),
     io_priority_(IOPRIO_CLASS_NONE),
-    cpu_priority_(InheritPriority),
-    object_creator_(NULL)
-{
-  if (CreateInThreadEvent::sEventType == -1)
-    CreateInThreadEvent::sEventType = QEvent::registerEventType();
-}
-
-BackgroundThreadBase::CreateInThreadEvent::CreateInThreadEvent(CreateInThreadRequest *req)
-  : QEvent(QEvent::Type(sEventType)),
-    req_(req)
+    cpu_priority_(InheritPriority)
 {
 }
 
-bool BackgroundThreadBase::ObjectCreator::event(QEvent* e) {
-  if (e->type() != CreateInThreadEvent::sEventType)
-    return false;
-
-  // Create the object, parented to this object so it gets destroyed when the
-  // thread ends.
-  CreateInThreadRequest* req = static_cast<CreateInThreadEvent*>(e)->req_;
-  req->object_ = req->meta_object_.newInstance(Q_ARG(QObject*, this));
-
-  // Wake up the calling thread
-  QMutexLocker l(&req->mutex_);
-  req->wait_condition_.wakeAll();
-
-  return true;
-}
-
-
 int BackgroundThreadBase::SetIOPriority() {
 #ifdef Q_OS_LINUX
   return syscall(SYS_ioprio_set, IOPRIO_WHO_PROCESS, gettid(),

src/core/backgroundthread.h

@@ -69,41 +69,10 @@ class BackgroundThreadBase : public QThread {
 
   virtual void Start(bool block = false);
 
-  // Creates a new QObject in this thread synchronously.
-  // The class T needs to have a Q_INVOKABLE constructor that takes a single
-  // QObject* argument.
-  template <typename T>
-      T* CreateInThread();
-
  signals:
   void Initialised();
 
  protected:
-  struct CreateInThreadRequest {
-    CreateInThreadRequest(const QMetaObject& meta_object)
-      : meta_object_(meta_object), object_(NULL) {}
-
-    const QMetaObject& meta_object_;
-    QObject* object_;
-
-    QWaitCondition wait_condition_;
-    QMutex mutex_;
-  };
-
-  struct CreateInThreadEvent : public QEvent {
-    CreateInThreadEvent(CreateInThreadRequest* req);
-
-    static int sEventType;
-
-    CreateInThreadRequest* req_;
-  };
-
-  class ObjectCreator : public QObject {
-   public:
-    bool event(QEvent *);
-  };
-
-
   int SetIOPriority();
   static int gettid();
 
@@ -119,8 +88,6 @@ class BackgroundThreadBase : public QThread {
 
   QWaitCondition started_wait_condition_;
   QMutex started_wait_condition_mutex_;
-
-  ObjectCreator* object_creator_;
 };
 
 // This is the templated class that stores and returns the worker object.
@@ -165,24 +132,6 @@ class BackgroundThreadFactoryImplementation : public BackgroundThreadFactory<Int
   }
 };
 
-
-
-template <typename T>
-T* BackgroundThreadBase::CreateInThread() {
-  // Create the request and lock it.
-  CreateInThreadRequest req(T::staticMetaObject);
-  QMutexLocker l(&req.mutex_);
-
-  // Post an event to the thread.  It will create the object and signal the
-  // wait condition. Ownership of the event is transferred to Qt.
-  CreateInThreadEvent* event = new CreateInThreadEvent(&req);
-  QCoreApplication::postEvent(object_creator_, event);
-
-  req.wait_condition_.wait(&req.mutex_);
-
-  return static_cast<T*>(req.object_);
-}
-
 template <typename InterfaceType>
 BackgroundThread<InterfaceType>::BackgroundThread(QObject *parent)
   : BackgroundThreadBase(parent)
@@ -216,7 +165,6 @@ void BackgroundThreadImplementation<InterfaceType, DerivedType>::run() {
   this->SetIOPriority();
 
   this->worker_.reset(new DerivedType);
-  this->object_creator_ = new BackgroundThreadBase::ObjectCreator;
 
   {
     // Tell the calling thread that we've initialised the worker.
@@ -227,7 +175,6 @@ void BackgroundThreadImplementation<InterfaceType, DerivedType>::run() {
   emit this->Initialised();
   QThread::exec();
 
-  delete this->object_creator_;
   this->worker_.reset();
 }
 

src/devices/connecteddevice.cpp

@@ -40,8 +40,9 @@ ConnectedDevice::ConnectedDevice(const QUrl& url, DeviceLister* lister,
   qDebug() << __PRETTY_FUNCTION__;
 
   // Create the backend in the database thread.
-  // The backend gets parented to the database.
-  backend_ = manager->database()->CreateInThread<LibraryBackend>();
+  backend_ = new LibraryBackend();
+  backend_->moveToThread(manager->database());
+
   backend_->Init(manager->database()->Worker(),
                  QString("device_%1_songs").arg(database_id),
                  QString("device_%1_directories").arg(database_id),

src/devices/devicemanager.cpp

@@ -159,7 +159,8 @@ DeviceManager::DeviceManager(BackgroundThread<Database>* database,
   connect(task_manager_, SIGNAL(TasksChanged()), SLOT(TasksChanged()));
 
   // Create the backend in the database thread
-  backend_ = database_->CreateInThread<DeviceDatabaseBackend>();
+  backend_ = new DeviceDatabaseBackend;
+  backend_->moveToThread(database);
   backend_->Init(database_->Worker());
 
   DeviceDatabaseBackend::DeviceList devices = backend_->GetAllDevices();

src/library/library.cpp

@@ -33,7 +33,9 @@ Library::Library(BackgroundThread<Database>* db_thread, TaskManager* task_manage
     watcher_factory_(new BackgroundThreadFactoryImplementation<LibraryWatcher, LibraryWatcher>),
     watcher_(NULL)
 {
-  backend_ = db_thread->CreateInThread<LibraryBackend>();
+  backend_ = new LibraryBackend;
+  backend()->moveToThread(db_thread);
+
   backend_->Init(db_thread->Worker(), kSongsTable, kDirsTable, kSubdirsTable, kFtsTable);
 
   model_ = new LibraryModel(backend_, this);

src/library/librarymodel.cpp

@@ -34,8 +34,8 @@ LibraryModel::LibraryModel(LibraryBackend* backend, QObject* parent)
   : SimpleTreeModel<LibraryItem>(new LibraryItem(this), parent),
     backend_(backend),
     dir_model_(new LibraryDirectoryModel(backend, this)),
-    artist_icon_(IconLoader::Load("x-clementine-artist")),
-    album_icon_(IconLoader::Load("x-clementine-album")),
+    artist_icon_(":/icons/22x22/x-clementine-artist"),
+    album_icon_(":/icons/22x22/x-clementine-album"),
     no_cover_icon_(":nocover.png")
 {
   root_->lazy_loaded = true;

src/ui/mainwindow.cpp

@@ -153,7 +153,8 @@ MainWindow::MainWindow(NetworkAccessManager* network, Engine::Type engine, QWidg
   qDebug() << t.restart() << "database startup";
 
   // Create some objects in the database thread
-  playlist_backend_ = database_->CreateInThread<PlaylistBackend>();
+  playlist_backend_ = new PlaylistBackend;
+  playlist_backend_->moveToThread(database_);
   playlist_backend_->SetDatabase(database_->Worker());
 
   qDebug() << t.restart() << "playlist backend";