chrome/browser/download/download_ui_controller.h

// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CHROME_BROWSER_DOWNLOAD_DOWNLOAD_UI_CONTROLLER_H_
#define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_UI_CONTROLLER_H_

#include <memory>
#include <set>

#include "components/download/content/public/all_download_item_notifier.h"

// This class handles the task of observing a single DownloadManager to
// notify the UI when a new download should be displayed. It invokes the
// OnNewDownloadReady() method of the Delegate when the target path is available
// for a new download.
class DownloadUIController
    : public download::AllDownloadItemNotifier::Observer {
 public:
  // The delegate is responsible for figuring out how to notify the UI.
  class Delegate {
   public:
    virtual ~Delegate();

    // This method is invoked to notify the UI of the new download |item|. Note
    // that |item| may be in any state by the time this method is invoked.
    virtual void OnNewDownloadReady(download::DownloadItem* item) = 0;

    // Notifies the controller that the main download button is clicked. Only
    // invoked by the download bubble UI.
    virtual void OnButtonClicked();
  };

  // |manager| is the download manager to observe for new downloads. If
  // |delegate.get()| is NULL, then the default delegate is constructed.
  //
  // On Android the default delegate notifies DownloadControllerAndroid. On
  // other platforms the target of the notification is a Browser object.
  //
  // Currently explicit delegates are only used for testing.
  DownloadUIController(content::DownloadManager* manager,
                       std::unique_ptr<Delegate> delegate);

  DownloadUIController(const DownloadUIController&) = delete;
  DownloadUIController& operator=(const DownloadUIController&) = delete;

  ~DownloadUIController() override;

  // Notifies the controller that the main download button is clicked. Currently
  // only invoked by the download bubble UI.
  void OnButtonClicked();

 private:
  void OnDownloadCreated(content::DownloadManager* manager,
                         download::DownloadItem* item) override;
  void OnDownloadUpdated(content::DownloadManager* manager,
                         download::DownloadItem* item) override;

  download::AllDownloadItemNotifier download_notifier_;

  std::unique_ptr<Delegate> delegate_;
};

#endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_UI_CONTROLLER_H_