biod/biod_storage.h

// Copyright 2016 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.

#ifndef BIOD_BIOD_STORAGE_H_
#define BIOD_BIOD_STORAGE_H_

#include <memory>
#include <string>
#include <unordered_set>

#include <base/callback.h>
#include <base/files/file_path.h>
#include <base/values.h>

#include "biod/biometrics_manager.h"
#include "biod/scoped_umask.h"

namespace biod {

class BiodStorage {
 public:
  using ReadRecordsCallback = base::Callback<bool(const std::string& user_id,
                                                  const std::string& label,
                                                  const std::string& record_id,
                                                  const base::Value& data)>;

  // Constructor set the file path to be
  // /home/root/<hash of user id>/biod/<BiometricsManager>/RecordUUID.
  // Callback load_record is run synchronously as each record is read back from
  // storage and loaded into biod.
  // TODO(mqg): Instead of callback, update ReadRecords to use out-parameter or
  // lambda.
  BiodStorage(const std::string& biometrics_manager_name,
              const ReadRecordsCallback& load_record);

  // Set root path to a different path for testing purpose only
  void SetRootPathForTesting(const base::FilePath& root_path);

  // Write one record to file in per user stateful. This is called whenever
  // we enroll a new record.
  bool WriteRecord(const BiometricsManager::Record& record,
                   std::unique_ptr<base::Value> data);

  // Read all records from file for all users in the set. Called whenever biod
  // starts or when a new user logs in.
  bool ReadRecords(const std::unordered_set<std::string>& user_ids);

  // Delete one record file. User will be able to do this via UI. True if
  // this record does not exist on disk.
  bool DeleteRecord(const std::string& user_id, const std::string& record_id);

  // Generate a uuid with guid.h for each record. Uuid is 128 bit number,
  // which is then turned into a string of format
  // xxxxxxxx_xxxx_xxxx_xxxx_xxxxxxxxxxxx, where x is a lowercase hex number.
  std::string GenerateNewRecordId();

 private:
  base::FilePath root_path_;
  std::string biometrics_manager_name_;
  ReadRecordsCallback load_record_;

  // Read all records from disk for a single user. Uses a file enumerator to
  // enumerate through all record files. Called whenever biod starts or when
  // a new user logs in.
  bool ReadRecordsForSingleUser(const std::string& user_id);
};
}  // namespace biod

#endif  // BIOD_BIOD_STORAGE_H_