SelfContainedViewListener.h

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/*
 * Copyright (c) 2019 pongasoft
 *
 * Licensed under the Apache License, Version 2.0 or the MIT license,
 * at your option. You may not use this file except in compliance with
 * one of these licenses. You may obtain copies of the licenses at:
 *
 * https://www.apache.org/licenses/LICENSE-2.0
 * https://opensource.org/licenses/MIT
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 *
 * @author Yan Pujante
 */
#pragma once
 
#include <vstgui4/vstgui/lib/iviewlistener.h>
#include <vstgui4/vstgui/lib/cview.h>
#include <pongasoft/logging/logging.h>
 
namespace pongasoft::VST::GUI::Views {
 
using namespace VSTGUI;

class SelfContainedViewListener : protected ViewListenerAdapter, public std::enable_shared_from_this<SelfContainedViewListener>
{
public:
  template<typename T, typename ...Args>
  static std::shared_ptr<T> create(CView *iView, Args&& ...iArgs)
  {
    // ensures that TView is a subclass of SelfContainedViewListener
    static_assert(std::is_convertible<T *, SelfContainedViewListener*>::value, "T must be a subclass of SelfContainedViewListener");
 
    auto res = std::make_shared<T>(std::forward<Args>(iArgs)...);
    res->registerView(iView);
    return res;
  }

  virtual void unregister()
  {
    if(fView)
    {
      fView->unregisterViewListener(this);
      fView = nullptr;
      fThis = nullptr;
    }
  }

  SelfContainedViewListener() = default;

  virtual std::shared_ptr<SelfContainedViewListener> registerView(CView *iView)
  {
    DCHECK_F(iView != nullptr);
 
    // first we close any prior connection if there was one
    unregister();
 
    fView = iView;
    fView->registerViewListener(this);
    fThis = shared_from_this();
 
    return fThis;
  }
 
protected:

  void viewWillDelete(CView *iView) override
  {
    DCHECK_F(iView == fView);
 
    unregister();
  }
 
protected:
  std::shared_ptr<SelfContainedViewListener> fThis{};
  CView *fView{};
};
 
}