//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.

//  This source code is licensed under both the GPLv2 (found in the

//  COPYING file in the root directory) and Apache 2.0 License

//  (found in the LICENSE.Apache file in the root directory).

//

// Copyright (c) 2011 The LevelDB Authors. All rights reserved.

// Use of this source code is governed by a BSD-style license that can be

// found in the LICENSE file. See the AUTHORS file for names of contributors.

#pragma once

#include <atomic>

#include <map>

#include <string>

#include <vector>

#include "env/composite_env_wrapper.h"

#include "port/port.h"

#include "rocksdb/env.h"

#include "rocksdb/status.h"

#include "rocksdb/system_clock.h"

namespace ROCKSDB_NAMESPACE {

class MemFile;

class MockFileSystem : public FileSystem {

 public:

  explicit MockFileSystem(const std::shared_ptr<SystemClock>& clock,

                          bool supports_direct_io = true);

  ~MockFileSystem() override;

  static const char* kClassName() { return "MemoryFileSystem"; }

  const char* Name() const override { return kClassName(); }

  IOStatus NewSequentialFile(const std::string& f, const FileOptions& file_opts,

                             std::unique_ptr<FSSequentialFile>* r,

                             IODebugContext* dbg) override;

  IOStatus NewRandomAccessFile(const std::string& f,

                               const FileOptions& file_opts,

                               std::unique_ptr<FSRandomAccessFile>* r,

                               IODebugContext* dbg) override;

  IOStatus NewRandomRWFile(const std::string& fname,

                           const FileOptions& file_opts,

                           std::unique_ptr<FSRandomRWFile>* result,

                           IODebugContext* dbg) override;

  IOStatus ReuseWritableFile(const std::string& fname,

                             const std::string& old_fname,

                             const FileOptions& file_opts,

                             std::unique_ptr<FSWritableFile>* result,

                             IODebugContext* dbg) override;

  IOStatus NewWritableFile(const std::string& fname,

                           const FileOptions& file_opts,

                           std::unique_ptr<FSWritableFile>* result,

                           IODebugContext* dbg) override;

  IOStatus ReopenWritableFile(const std::string& fname,

                              const FileOptions& options,

                              std::unique_ptr<FSWritableFile>* result,

                              IODebugContext* dbg) override;

  IOStatus NewDirectory(const std::string& /*name*/, const IOOptions& io_opts,

                        std::unique_ptr<FSDirectory>* result,

                        IODebugContext* dbg) override;

  IOStatus FileExists(const std::string& fname, const IOOptions& /*io_opts*/,

                      IODebugContext* /*dbg*/) override;

  IOStatus GetChildren(const std::string& dir, const IOOptions& options,

                       std::vector<std::string>* result,

                       IODebugContext* dbg) override;

  IOStatus DeleteFile(const std::string& fname, const IOOptions& options,

                      IODebugContext* dbg) override;

  IOStatus Truncate(const std::string& fname, size_t size,

                    const IOOptions& options, IODebugContext* dbg) override;

  IOStatus CreateDir(const std::string& dirname, const IOOptions& options,

                     IODebugContext* dbg) override;

  IOStatus CreateDirIfMissing(const std::string& dirname,

                              const IOOptions& options,

                              IODebugContext* dbg) override;

  IOStatus DeleteDir(const std::string& dirname, const IOOptions& options,

                     IODebugContext* dbg) override;

  IOStatus GetFileSize(const std::string& fname, const IOOptions& options,

                       uint64_t* file_size, IODebugContext* dbg) override;

  IOStatus GetFileModificationTime(const std::string& fname,

                                   const IOOptions& options,

                                   uint64_t* file_mtime,

                                   IODebugContext* dbg) override;

  IOStatus RenameFile(const std::string& src, const std::string& target,

                      const IOOptions& options, IODebugContext* dbg) override;

  IOStatus LinkFile(const std::string& /*src*/, const std::string& /*target*/,

                    const IOOptions& /*options*/,

                    IODebugContext* /*dbg*/) override;

  IOStatus LockFile(const std::string& fname, const IOOptions& options,

                    FileLock** lock, IODebugContext* dbg) override;

  IOStatus UnlockFile(FileLock* lock, const IOOptions& options,

                      IODebugContext* dbg) override;

  IOStatus GetTestDirectory(const IOOptions& options, std::string* path,

                            IODebugContext* dbg) override;

  IOStatus NewLogger(const std::string& fname, const IOOptions& io_opts,

                     std::shared_ptr<Logger>* result,

                     IODebugContext* dbg) override;

  // Get full directory name for this db.

  IOStatus GetAbsolutePath(const std::string& db_path,

                           const IOOptions& /*options*/,

                           std::string* output_path,

                           IODebugContext* /*dbg*/) override;

  IOStatus IsDirectory(const std::string& /*path*/,

                       const IOOptions& /*options*/, bool* /*is_dir*/,

                       IODebugContext* /*dgb*/) override {

    return IOStatus::NotSupported("IsDirectory");

  }

  Status CorruptBuffer(const std::string& fname);

  Status PrepareOptions(const ConfigOptions& options) override;

 private:

  bool RenameFileInternal(const std::string& src, const std::string& dest);

  void DeleteFileInternal(const std::string& fname);

  bool GetChildrenInternal(const std::string& fname,

                           std::vector<std::string>* results);

  std::string NormalizeMockPath(const std::string& path);

 private:

  // Map from filenames to MemFile objects, representing a simple file system.

  port::Mutex mutex_;

  std::map<std::string, MemFile*> file_map_;  // Protected by mutex_.

  std::shared_ptr<SystemClock> system_clock_;

  SystemClock* clock_;

  bool supports_direct_io_;

};

class MockEnv : public CompositeEnvWrapper {

 public:

  static MockEnv* Create(Env* base);

  static MockEnv* Create(Env* base, const std::shared_ptr<SystemClock>& clock);

  static const char* kClassName() { return "MockEnv"; }

  const char* Name() const override { return kClassName(); }

  Status CorruptBuffer(const std::string& fname);

 private:

  MockEnv(Env* env, const std::shared_ptr<FileSystem>& fs,

          const std::shared_ptr<SystemClock>& clock);

};

}  // namespace ROCKSDB_NAMESPACE