mergerfs/src/fs_inode.hpp

/*
  ISC License

  Copyright (c) 2026, Antonio SJ Musumeci <trapexit@spawn.link>

  Permission to use, copy, modify, and/or distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

#pragma once

#include "base_types.h"
#include "fs_path.hpp"
#include "fuse_kernel.h"

#include <cstddef>
#include <string>
#include <string_view>

#include <sys/stat.h>


namespace fs
{
  namespace inode
  {
    enum class Algo
    {
      PASSTHROUGH,
      PATH_HASH,
      PATH_HASH32,
      DEVINO_HASH,
      DEVINO_HASH32,
      HYBRID_HASH,
      HYBRID_HASH32,
    };

    class ReaddirCalc
    {
    public:
      ReaddirCalc(const fs::path &branch_path,
                  const fs::path &dirpath);

    public:
      u64 calc(const char   *name,
               const size_t  namelen,
               const mode_t  mode,
               const ino_t   ino);

    private:
      Algo        _algo;
      u64         _branch_seed;
      std::string _fusepath;
      std::size_t _filename_offset;
    };

    int set_algo(const std::string &s);
    std::string get_algo(void);

    u64 calc(const std::string &basepath,
             const std::string &fusepath,
             const mode_t           mode,
             const ino_t            ino);
    u64 calc(const fs::path    &basepath,
             const fs::path    &fusepath,
             const mode_t       mode,
             const ino_t        ino);

    void calc(const std::string &basepath,
              const std::string &fusepath,
              struct stat            *st);
    void calc(const fs::path    &basepath,
              const fs::path    &fusepath,
              struct stat       *st);
    void calc(const std::string &basepath,
              const std::string &fusepath,
              struct fuse_statx *st);
    void calc(const fs::path    &basepath,
              const fs::path    &fusepath,
              struct fuse_statx *st);
  }
}