sapling/eden/fs/fuse/DirList.h

/*
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This software may be used and distributed according to the terms of the
 * GNU General Public License version 2.
 */

#pragma once
#include <folly/Range.h>
#include <sys/stat.h>
#include <memory>
#include "eden/fs/utils/DirType.h"

namespace facebook {
namespace eden {

/**
 * Helper for populating directory listings.
 */
class DirList {
  std::unique_ptr<char[]> buf_;
  char* end_;
  char* cur_;

 public:
  struct ExtractedEntry {
    std::string name;
    ino_t inode;
    dtype_t type;
    off_t offset;
  };

  explicit DirList(size_t maxSize);

  DirList(const DirList&) = delete;
  DirList& operator=(const DirList&) = delete;
  DirList(DirList&&) = default;
  DirList& operator=(DirList&&) = default;

  /**
   * Add a new dirent to the list.
   * Returns true on success or false if the list is full.
   */
  bool add(folly::StringPiece name, ino_t inode, dtype_t type, off_t off);

  folly::StringPiece getBuf() const;

  /**
   * Helper function that parses an accumulated buffer back into its constituent
   * parts.
   */
  std::vector<ExtractedEntry> extract() const;
};

} // namespace eden
} // namespace facebook