lib/cycle-check.h

   1 /* help detect directory cycles efficiently
   2
   3    Copyright (C) 2003-2004, 2006, 2009-2019 Free Software Foundation, Inc.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 /* Written by Jim Meyering */
  19
  20 #ifndef CYCLE_CHECK_H
  21 # define CYCLE_CHECK_H 1
  22
  23 # include <stdint.h>
  24 # include <stdbool.h>
  25 # include "dev-ino.h"
  26 # include "same-inode.h"
  27
  28 struct cycle_check_state
  29 {
  30   struct dev_ino dev_ino;
  31   uintmax_t chdir_counter;
  32   int magic;
  33 };
  34
  35 void cycle_check_init (struct cycle_check_state *state);
  36 bool cycle_check (struct cycle_check_state *state, struct stat const *sb);
  37
  38 # define CYCLE_CHECK_REFLECT_CHDIR_UP(State, SB_dir, SB_subdir) \
  39   do                                                            \
  40     {                                                           \
  41       /* You must call cycle_check at least once before using this macro.  */ \
  42       if ((State)->chdir_counter == 0)                          \
  43         abort ();                                               \
  44       if (SAME_INODE ((State)->dev_ino, SB_subdir))             \
  45         {                                                       \
  46           (State)->dev_ino.st_dev = (SB_dir).st_dev;            \
  47           (State)->dev_ino.st_ino = (SB_dir).st_ino;            \
  48         }                                                       \
  49     }                                                           \
  50   while (0)
  51
  52 #endif