ui/base/data_transfer_policy/data_transfer_policy_controller.h

// Copyright 2020 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_BASE_DATA_TRANSFER_POLICY_DATA_TRANSFER_POLICY_CONTROLLER_H_
#define UI_BASE_DATA_TRANSFER_POLICY_DATA_TRANSFER_POLICY_CONTROLLER_H_

#include "base/component_export.h"
#include "ui/base/data_transfer_policy/data_transfer_endpoint.h"

namespace ui {

// The DataTransfer policy controller controls transferring data via
// drag-and-drop and clipboard read operations. It allows/disallows transferring
// the data given the source of the data and the destination trying to access
// the data and a set of rules controlling these source and destination.
class COMPONENT_EXPORT(UI_BASE_DATA_TRANSFER_POLICY)
    DataTransferPolicyController {
 public:
  // Returns a pointer to the existing instance of the class.
  static DataTransferPolicyController* Get();

  // Returns true if an instance exists, without forcing an initialization.
  static bool HasInstance();

  // Deletes the existing instance of the class if it's already created.
  // Indicates that restricting data transfer is no longer required.
  static void DeleteInstance();

  // nullptr can be passed instead of `data_src` or `data_dst`. If clipboard
  // read is not allowed, this function will show a notification to the user.
  virtual bool IsClipboardReadAllowed(
      const DataTransferEndpoint* const data_src,
      const DataTransferEndpoint* const data_dst) = 0;

  // nullptr can be passed instead of `data_src` or `data_dst`. If dropping the
  // data is not allowed, this function will show a notification to the user.
  virtual bool IsDragDropAllowed(const DataTransferEndpoint* const data_src,
                                 const DataTransferEndpoint* const data_dst,
                                 const bool is_drop) = 0;

 protected:
  DataTransferPolicyController();
  virtual ~DataTransferPolicyController();

 private:
  // A singleton of DataTransferPolicyController. Equals nullptr when there's
  // not any data transfer restrictions required.
  static DataTransferPolicyController* g_data_transfer_policy_controller_;
};

}  // namespace ui

#endif  // UI_BASE_DATA_TRANSFER_POLICY_DATA_TRANSFER_POLICY_CONTROLLER_H_