text: // Copyright 2014 The Chromium OS Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  // Wrapper around /etc/os-release and /etc/os-release.d.
  // Standard fields can come from both places depending on how we set them. They
  // should always be accessed through this interface.
  
  #ifndef LIBBRILLO_BRILLO_OSRELEASE_READER_H_
  #define LIBBRILLO_BRILLO_OSRELEASE_READER_H_
  
  #include <string>
  #include <vector>
  
  #include <brillo/brillo_export.h>
  #include <brillo/key_value_store.h>
  #include <gtest/gtest_prod.h>
  
  namespace brillo {
  
  class BRILLO_EXPORT OsReleaseReader final {
   public:
    // Create an empty reader
    OsReleaseReader() = default;
    OsReleaseReader(const OsReleaseReader&) = delete;
    OsReleaseReader& operator=(const OsReleaseReader&) = delete;
  
    // Loads the key=value pairs from either /etc/os-release.d/<KEY> or
    // /etc/os-release.
    void Load();
  
    // Same as the private Load method.
    // This need to be public so that services can use it in testing mode (for
    // autotest tests for example).
    // This should not be used in production so suffix it with TestingOnly to
    // make it obvious.
    void LoadTestingOnly(const base::FilePath& root_dir);
  
    // Getter for the given key. Returns whether the key was found on the store.
    bool GetString(const std::string& key, std::string* value) const;
  
    // Getter for all the keys in /etc/os-release.
    std::vector<std::string> GetKeys() const;
  
   private:
    // The map storing all the key-value pairs.
    KeyValueStore store_;
  
    // os-release can be lazily loaded if need be.
    bool initialized_;
  
    // Load the data from a given root_dir.
    BRILLO_PRIVATE void Load(const base::FilePath& root_dir);
  };
  
  }  // namespace brillo
  
  #endif  // LIBBRILLO_BRILLO_OSRELEASE_READER_H_
  