base/third_party/xdg_user_dirs/xdg_user_dir_lookup.cc

   1 /*
   2   This file is not licenced under the GPL like the rest of the code.
   3   Its is under the MIT license, to encourage reuse by cut-and-paste.
   4
   5   Copyright (c) 2007 Red Hat, inc
   6
   7   Permission is hereby granted, free of charge, to any person
   8   obtaining a copy of this software and associated documentation files
   9   (the "Software"), to deal in the Software without restriction,
  10   including without limitation the rights to use, copy, modify, merge,
  11   publish, distribute, sublicense, and/or sell copies of the Software,
  12   and to permit persons to whom the Software is furnished to do so,
  13   subject to the following conditions:
  14
  15   The above copyright notice and this permission notice shall be
  16   included in all copies or substantial portions of the Software.
  17
  18   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  19   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  20   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  21   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  22   BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  23   ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  24   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  25   SOFTWARE.
  26 */
  27
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31
  32 /**
  33  * xdg_user_dir_lookup_with_fallback:
  34  * @type: a string specifying the type of directory
  35  * @fallback: value to use if the directory isn't specified by the user
  36  * @returns: a newly allocated absolute pathname
  37  *
  38  * Looks up a XDG user directory of the specified type.
  39  * Example of types are "DESKTOP" and "DOWNLOAD".
  40  *
  41  * In case the user hasn't specified any directory for the specified
  42  * type the value returned is @fallback.
  43  *
  44  * The return value is newly allocated and must be freed with
  45  * free(). The return value is never NULL if @fallback != NULL, unless
  46  * out of memory.
  47  **/
  48 static char *
  49 xdg_user_dir_lookup_with_fallback (const char *type, const char *fallback)
  50 {
  51   FILE *file;
  52   char *home_dir, *config_home, *config_file;
  53   char buffer[512];
  54   char *user_dir;
  55   char *p, *d;
  56   int len;
  57   int relative;
  58
  59   home_dir = getenv ("HOME");
  60
  61   if (home_dir == NULL)
  62     goto error;
  63
  64   config_home = getenv ("XDG_CONFIG_HOME");
  65   if (config_home == NULL || config_home[0] == 0)
  66     {
  67       config_file = (char*) malloc (strlen (home_dir) + strlen ("/.config/user-dirs.dirs") + 1);
  68       if (config_file == NULL)
  69         goto error;
  70
  71       strcpy (config_file, home_dir);
  72       strcat (config_file, "/.config/user-dirs.dirs");
  73     }
  74   else
  75     {
  76       config_file = (char*) malloc (strlen (config_home) + strlen ("/user-dirs.dirs") + 1);
  77       if (config_file == NULL)
  78         goto error;
  79
  80       strcpy (config_file, config_home);
  81       strcat (config_file, "/user-dirs.dirs");
  82     }
  83
  84   file = fopen (config_file, "r");
  85   free (config_file);
  86   if (file == NULL)
  87     goto error;
  88
  89   user_dir = NULL;
  90   while (fgets (buffer, sizeof (buffer), file))
  91     {
  92       /* Remove newline at end */
  93       len = strlen (buffer);
  94       if (len > 0 && buffer[len-1] == '\n')
  95         buffer[len-1] = 0;
  96
  97       p = buffer;
  98       while (*p == ' ' || *p == '\t')
  99         p++;
 100
 101       if (strncmp (p, "XDG_", 4) != 0)
 102         continue;
 103       p += 4;
 104       if (strncmp (p, type, strlen (type)) != 0)
 105         continue;
 106       p += strlen (type);
 107       if (strncmp (p, "_DIR", 4) != 0)
 108         continue;
 109       p += 4;
 110
 111       while (*p == ' ' || *p == '\t')
 112         p++;
 113
 114       if (*p != '=')
 115         continue;
 116       p++;
 117
 118       while (*p == ' ' || *p == '\t')
 119         p++;
 120
 121       if (*p != '"')
 122         continue;
 123       p++;
 124
 125       relative = 0;
 126       if (strncmp (p, "$HOME/", 6) == 0)
 127         {
 128           p += 6;
 129           relative = 1;
 130         }
 131       else if (*p != '/')
 132         continue;
 133
 134       if (relative)
 135         {
 136           user_dir = (char*) malloc (strlen (home_dir) + 1 + strlen (p) + 1);
 137           if (user_dir == NULL)
 138             goto error2;
 139
 140           strcpy (user_dir, home_dir);
 141           strcat (user_dir, "/");
 142         }
 143       else
 144         {
 145           user_dir = (char*) malloc (strlen (p) + 1);
 146           if (user_dir == NULL)
 147             goto error2;
 148
 149           *user_dir = 0;
 150         }
 151
 152       d = user_dir + strlen (user_dir);
 153       while (*p && *p != '"')
 154         {
 155           if ((*p == '\\') && (*(p+1) != 0))
 156             p++;
 157           *d++ = *p++;
 158         }
 159       *d = 0;
 160     }
 161 error2:
 162   fclose (file);
 163
 164   if (user_dir)
 165     return user_dir;
 166
 167  error:
 168   if (fallback)
 169     return strdup (fallback);
 170   return NULL;
 171 }
 172
 173 /**
 174  * xdg_user_dir_lookup:
 175  * @type: a string specifying the type of directory
 176  * @returns: a newly allocated absolute pathname
 177  *
 178  * Looks up a XDG user directory of the specified type.
 179  * Example of types are "DESKTOP" and "DOWNLOAD".
 180  *
 181  * The return value is always != NULL (unless out of memory),
 182  * and if a directory
 183  * for the type is not specified by the user the default
 184  * is the home directory. Except for DESKTOP which defaults
 185  * to ~/Desktop.
 186  *
 187  * The return value is newly allocated and must be freed with
 188  * free().
 189  **/
 190 char *
 191 xdg_user_dir_lookup (const char *type)
 192 {
 193   char *dir, *home_dir, *user_dir;
 194
 195   dir = xdg_user_dir_lookup_with_fallback (type, NULL);
 196   if (dir != NULL)
 197     return dir;
 198
 199   home_dir = getenv ("HOME");
 200
 201   if (home_dir == NULL)
 202     return strdup ("/tmp");
 203
 204   /* Special case desktop for historical compatibility */
 205   if (strcmp (type, "DESKTOP") == 0)
 206     {
 207       user_dir = (char*) malloc (strlen (home_dir) + strlen ("/Desktop") + 1);
 208       if (user_dir == NULL)
 209         return NULL;
 210
 211       strcpy (user_dir, home_dir);
 212       strcat (user_dir, "/Desktop");
 213       return user_dir;
 214     }
 215
 216   return strdup (home_dir);
 217 }
 218
 219 #ifdef STANDALONE_XDG_USER_DIR_LOOKUP
 220 int
 221 main (int argc, char *argv[])
 222 {
 223   if (argc != 2)
 224     {
 225       fprintf (stderr, "Usage %s <dir-type>\n", argv[0]);
 226       exit (1);
 227     }
 228
 229   printf ("%s\n", xdg_user_dir_lookup (argv[1]));
 230   return 0;
 231 }
 232 #endif