//  Copyright (c) Facebook, Inc. and its affiliates. 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).

#pragma once

#include <utility>

#include "rocksdb/file_system.h"

namespace ROCKSDB_NAMESPACE {

// An abstract FileSystem wrapper that creates a view of an existing

// FileSystem by remapping names in some way.

//

// This class has not been fully analyzed for providing strong security

// guarantees.

class RemapFileSystem : public FileSystemWrapper {

 public:

  explicit RemapFileSystem(const std::shared_ptr<FileSystem>& base);

 protected:

  // Returns status and mapped-to path in the wrapped filesystem.

  // If it returns non-OK status, the returned path should not be used.

  virtual std::pair<IOStatus, std::string> EncodePath(

      const std::string& path) = 0;

  // Similar to EncodePath() except used in cases in which it is OK for

  // no file or directory on 'path' to already exist, such as if the

  // operation would create one. However, the parent of 'path' is expected

  // to exist for the operation to succeed.

  // Default implementation: call EncodePath

  virtual std::pair<IOStatus, std::string> EncodePathWithNewBasename(

      const std::string& path);

 public:

  // Left abstract:

  // const char* Name() const override { ... }

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

  bool IsInstanceOf(const std::string& id) const override {

    if (id == kClassName()) {

      return true;

    } else {

      return FileSystemWrapper::IsInstanceOf(id);

    }

  }

  Status RegisterDbPaths(const std::vector<std::string>& paths) override;

  Status UnregisterDbPaths(const std::vector<std::string>& paths) override;

  IOStatus NewSequentialFile(const std::string& fname,

                             const FileOptions& options,

                             std::unique_ptr<FSSequentialFile>* result,

                             IODebugContext* dbg) override;

  IOStatus NewRandomAccessFile(const std::string& fname,

                               const FileOptions& options,

                               std::unique_ptr<FSRandomAccessFile>* result,

                               IODebugContext* dbg) override;

  IOStatus NewWritableFile(const std::string& fname, const FileOptions& options,

                           std::unique_ptr<FSWritableFile>* result,

                           IODebugContext* dbg) override;

  IOStatus ReuseWritableFile(const std::string& fname,

                             const std::string& old_fname,

                             const FileOptions& options,

                             std::unique_ptr<FSWritableFile>* result,

                             IODebugContext* dbg) override;

  IOStatus NewRandomRWFile(const std::string& fname, const FileOptions& options,

                           std::unique_ptr<FSRandomRWFile>* result,

                           IODebugContext* dbg) override;

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

                        std::unique_ptr<FSDirectory>* result,

                        IODebugContext* dbg) override;

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

                      IODebugContext* dbg) override;

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

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

                       IODebugContext* dbg) override;

  IOStatus GetChildrenFileAttributes(const std::string& dir,

                                     const IOOptions& options,

                                     std::vector<FileAttributes>* result,

                                     IODebugContext* dbg) override;

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

                       bool* is_dir, IODebugContext* dbg) override;

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

                      const IOOptions& options, IODebugContext* dbg) override;

  IOStatus LinkFile(const std::string& src, const std::string& dest,

                    const IOOptions& options, IODebugContext* dbg) override;

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

                    FileLock** lock, IODebugContext* dbg) override;

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

                     std::shared_ptr<Logger>* result,

                     IODebugContext* dbg) override;

  IOStatus GetAbsolutePath(const std::string& db_path, const IOOptions& options,

                           std::string* output_path,

                           IODebugContext* dbg) override;

};

}  // namespace ROCKSDB_NAMESPACE