lib/libalpm/filelist.c


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/*
 *  filelist.c
 *
 *  Copyright (c) 2012-2013 Pacman Development Team <pacman-dev@archlinux.org>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <limits.h>
#include <string.h>
#include <sys/stat.h>

/* libalpm */
#include "filelist.h"
#include "util.h"

/* Returns the difference of the provided two lists of files.
 * Pre-condition: both lists are sorted!
 * When done, free the list but NOT the contained data.
 */
alpm_list_t *_alpm_filelist_difference(alpm_filelist_t *filesA,
    alpm_filelist_t *filesB)
{
  alpm_list_t *ret = NULL;
  size_t ctrA = 0, ctrB = 0;

  while(ctrA < filesA->count && ctrB < filesB->count) {
    char *strA = filesA->files[ctrA].name;
    char *strB = filesB->files[ctrB].name;

    int cmp = strcmp(strA, strB);
    if(cmp < 0) {
      /* item only in filesA, qualifies as a difference */
      ret = alpm_list_add(ret, strA);
      ctrA++;
    } else if(cmp > 0) {
      ctrB++;
    } else {
      ctrA++;
      ctrB++;
    }
  }

  /* ensure we have completely emptied pA */
  while(ctrA < filesA->count) {
    ret = alpm_list_add(ret, filesA->files[ctrA].name);
    ctrA++;
  }

  return ret;
}

/* Returns the intersection of the provided two lists of files.
 * Pre-condition: both lists are sorted!
 * When done, free the list but NOT the contained data.
 */
alpm_list_t *_alpm_filelist_intersection(alpm_filelist_t *filesA,
    alpm_filelist_t *filesB)
{
  alpm_list_t *ret = NULL;
  size_t ctrA = 0, ctrB = 0;

  while(ctrA < filesA->count && ctrB < filesB->count) {
    int cmp, isdirA, isdirB;
    char *strA, *strB;

    isdirA = 0;
    strA = filesA->files[ctrA].name;
    if(strA[strlen(strA)-1] == '/') {
      isdirA = 1;
      strA = strndup(strA, strlen(strA)-1);
    }

    isdirB = 0;
    strB = filesB->files[ctrB].name;
    if(strB[strlen(strB)-1] == '/') {
      isdirB = 1;
      strB = strndup(strB, strlen(strB)-1);
    }

    cmp = strcmp(strA, strB);
    if(cmp < 0) {
      ctrA++;
    } else if(cmp > 0) {
      ctrB++;
    } else {
      /* TODO: this creates conflicts between a symlink to a directory in
       * one package and a real directory in the other. For example,
       * lib -> /usr/lib in pkg1 and /lib in pkg2.  This would be allowed
       * when installing one package at a time _provided_ pkg1 is installed
       * first. This will need adjusted if the order of package install can
       * be guaranteed to install the symlink first */

      /* when not directories, item in both qualifies as an intersect */
      if(! (isdirA && isdirB)) {
        ret = alpm_list_add(ret, filesA->files[ctrA].name);
      }
      ctrA++;
      ctrB++;
    }

    if(isdirA) {
      free(strA);
    }
    if(isdirB) {
      free(strB);
    }
  }

  return ret;
}

/* Helper function for comparing files list entries
 */
int _alpm_files_cmp(const void *f1, const void *f2)
{
  const alpm_file_t *file1 = f1;
  const alpm_file_t *file2 = f2;
  return strcmp(file1->name, file2->name);
}

alpm_file_t SYMEXPORT *alpm_filelist_contains(alpm_filelist_t *filelist,
    const char *path)
{
  alpm_file_t key;

  if(!filelist) {
    return NULL;
  }

  key.name = (char *)path;

  return bsearch(&key, filelist->files, filelist->count,
      sizeof(alpm_file_t), _alpm_files_cmp);
}

/* vim: set ts=2 sw=2 noet: */