lib/dpkg/fsys-iter.c

   1 /*
   2  * libdpkg - Debian packaging suite library routines
   3  * fsys-iter.c - filesystem nodes iterators
   4  *
   5  * Copyright © 1995 Ian Jackson <ijackson@chiark.greenend.org.uk>
   6  * Copyright © 2000, 2001 Wichert Akkerman <wakkerma@debian.org>
   7  * Copyright © 2008-2014 Guillem Jover <guillem@debian.org>
   8  *
   9  * This is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  21  */
  22
  23 #include <config.h>
  24 #include <compat.h>
  25
  26 #include <stdlib.h>
  27
  28 #include <dpkg/dpkg.h>
  29 #include <dpkg/dpkg-db.h>
  30 #include <dpkg/pkg-list.h>
  31
  32 #include "fsys.h"
  33
  34 /*
  35  * Reverse iterator.
  36  */
  37
  38 /*
  39  * Initializes an iterator that appears to go through the file list ‘files’
  40  * in reverse order, returning the namenode from each. What actually happens
  41  * is that we walk the list here, building up a reverse list, and then peel
  42  * it apart one entry at a time.
  43  */
  44 void
  45 fsys_hash_rev_iter_init(struct fsys_hash_rev_iter *iter,
  46                         struct fsys_namenode_list *files)
  47 {
  48         struct fsys_namenode_list *newent;
  49
  50         iter->todo = NULL;
  51         while (files) {
  52                 newent = m_malloc(sizeof(*newent));
  53                 newent->namenode = files->namenode;
  54                 newent->next = iter->todo;
  55                 iter->todo = newent;
  56                 files = files->next;
  57         }
  58 }
  59
  60 struct fsys_namenode *
  61 fsys_hash_rev_iter_next(struct fsys_hash_rev_iter *iter)
  62 {
  63         struct fsys_namenode *next;
  64         struct fsys_namenode_list *todo;
  65
  66         todo = iter->todo;
  67         if (!todo)
  68                 return NULL;
  69         next = todo->namenode;
  70         iter->todo = todo->next;
  71         free(todo);
  72
  73         return next;
  74 }
  75
  76 /*
  77  * Clients must call this function to clean up the fsys_hash_rev_iter
  78  * if they wish to break out of the iteration before it is all done.
  79  * Calling this function is not necessary if fsys_hash_rev_iter_next() has
  80  * been called until it returned 0.
  81  */
  82 void
  83 fsys_hash_rev_iter_abort(struct fsys_hash_rev_iter *iter)
  84 {
  85         while (fsys_hash_rev_iter_next(iter))
  86                 ;
  87 }
  88
  89 /*
  90  * Iterator for packages owning a file.
  91  */
  92
  93 struct fsys_node_pkgs_iter {
  94         struct pkg_list *pkg_node;
  95 };
  96
  97 struct fsys_node_pkgs_iter *
  98 fsys_node_pkgs_iter_new(struct fsys_namenode *fnn)
  99 {
 100         struct fsys_node_pkgs_iter *iter;
 101
 102         iter = m_malloc(sizeof(*iter));
 103         iter->pkg_node = fnn->packages;
 104
 105         return iter;
 106 }
 107
 108 struct pkginfo *
 109 fsys_node_pkgs_iter_next(struct fsys_node_pkgs_iter *iter)
 110 {
 111         struct pkg_list *pkg_node;
 112
 113         if (iter->pkg_node == NULL)
 114                 return NULL;
 115
 116         pkg_node = iter->pkg_node;
 117         iter->pkg_node = pkg_node->next;
 118
 119         return pkg_node->pkg;
 120 }
 121
 122 void
 123 fsys_node_pkgs_iter_free(struct fsys_node_pkgs_iter *iter)
 124 {
 125         free(iter);
 126 }