observer.h

// Copyright 2025 The Pigweed Authors
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// 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.
#pragma once
 
#include <cstddef>
 
namespace pw {
 
class MultiBufObserver {
 public:
  enum class Event {
    kBytesAdded,
 
    kBytesRemoved,
 
    kLayerAdded,
 
    kLayerRemoved,
  };
 
  virtual ~MultiBufObserver() = default;
 
  void Notify(Event event, size_t value) { DoNotify(event, value); }
 
 private:
  virtual void DoNotify(Event event, size_t value) = 0;
};
 
}  // namespace pw