responder.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 "pw_bytes/span.h"
#include "pw_i2c/address.h"
#include "pw_result/result.h"
#include "pw_status/status.h"
 
namespace pw::i2c {
 
class ResponderEvents {
 public:
  virtual ~ResponderEvents() = default;
 
  [[nodiscard]] virtual bool OnStartRead() { return true; }
 
  [[nodiscard]] virtual bool OnStartWrite() { return true; }
 
  [[nodiscard]] virtual bool OnWrite(ConstByteSpan data) {
    // Provide a name for argument to be used in doxygen
    static_cast<void>(data);
    return false;
  }
 
  [[nodiscard]] virtual Result<ConstByteSpan> OnRead() {
    return Status::Unimplemented();
  }
 
  [[nodiscard]] virtual bool OnStop() { return true; }
};
 
class Responder {
 public:
  constexpr Responder(Address address, ResponderEvents& events)
      : address_(address), events_(events) {}
  virtual ~Responder() = default;
 
  Status Enable() { return DoEnable(); }
 
  Status Disable() { return DoDisable(); }
 
 protected:
  virtual Status DoEnable() = 0;
 
  virtual Status DoDisable() = 0;
 
  bool OnStartRead() { return events_.OnStartRead(); }
 
  bool OnStartWrite() { return events_.OnStartWrite(); }
 
  bool OnWrite(ConstByteSpan data) { return events_.OnWrite(data); }
 
  Result<ConstByteSpan> OnRead() { return events_.OnRead(); }
 
  bool OnStop() { return events_.OnStop(); }
 
  const Address& address() const { return address_; }
 
 private:
  const Address address_;
  ResponderEvents& events_;
};
 
}  // namespace pw::i2c