instance_nums.h

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//
// Copyright (C) 2022 The Android Open Source Project
//
// 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
//
//      http://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 <cstdint>
#include <optional>
#include <string>
#include <vector>
 
#include "cuttlefish/common/libs/utils/result.h"
 
namespace cuttlefish {
 
class InstanceNumsCalculator {
 public:
  InstanceNumsCalculator& FromFlags(const std::vector<std::string>&) &;
  InstanceNumsCalculator FromFlags(const std::vector<std::string>&) &&;
 
  InstanceNumsCalculator& FromGlobalGflags() &;
  InstanceNumsCalculator FromGlobalGflags() &&;
 
  InstanceNumsCalculator& BaseInstanceNum(std::int32_t) &;
  InstanceNumsCalculator BaseInstanceNum(std::int32_t) &&;
 
  InstanceNumsCalculator& NumInstances(std::int32_t) &;
  InstanceNumsCalculator NumInstances(std::int32_t) &&;
 
  InstanceNumsCalculator& InstanceNums(const std::string&) &;
  InstanceNumsCalculator InstanceNums(const std::string&) &&;
 
  // if any element is duplicated, only the first one of them is taken.
  //   E.g. InstanceNums({1, 2, 3, 2}) == InstanceNums({1, 2, 3})
  // That is how the code was implemented in Android 14
  InstanceNumsCalculator& InstanceNums(std::vector<std::int32_t>) &;
  InstanceNumsCalculator InstanceNums(std::vector<std::int32_t>) &&;
 
  Result<std::vector<std::int32_t>> CalculateFromFlags();
 
  // Calculates the base from the --instance_nums, --base_instance_num,
  // CUTTLEFISH_INSTANCE, suffix of the user account, and the default value.
  // Then, figures out the set if ids.
  Result<std::vector<std::int32_t>> Calculate();
 
 private:
  template <typename T>
  void TrySet(T& field, Result<T> result);
 
  Result<void> setter_result_;
  std::optional<std::int32_t> base_instance_num_;
  std::optional<std::int32_t> num_instances_;
  std::vector<std::int32_t> instance_nums_;
};
 
}  // namespace cuttlefish