test/filesystem_for_testing.h

// Copyright 2017 Google LLC
//
// 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.

// Implements a fake filesystem, useful for tests.
#ifndef CPU_FEATURES_TEST_FILESYSTEM_FOR_TESTING_H_
#define CPU_FEATURES_TEST_FILESYSTEM_FOR_TESTING_H_

#include <memory>
#include <string>
#include <unordered_map>

#include "internal/filesystem.h"

namespace cpu_features {

class FakeFile {
 public:
  explicit FakeFile(int file_descriptor, const char* content);
  ~FakeFile();

  void Open();
  void Close();
  int Read(int fd, void* buf, size_t count);

  int GetFileDescriptor() const { return file_descriptor_; }

 private:
  const int file_descriptor_;
  const std::string content_;
  bool opened_ = false;
  size_t head_index_ = 0;
};

class FakeFilesystem {
 public:
  void Reset();
  FakeFile* CreateFile(const std::string& filename, const char* content);
  FakeFile* FindFileOrDie(const int file_descriptor) const;
  FakeFile* FindFileOrNull(const std::string& filename) const;

 private:
  int next_file_descriptor_ = 0;
  std::unordered_map<std::string, std::unique_ptr<FakeFile>> files_;
};

FakeFilesystem& GetEmptyFilesystem();

}  // namespace cpu_features

#endif  // CPU_FEATURES_TEST_FILESYSTEM_FOR_TESTING_H_