dir-iterator.c

   1 #include "git-compat-util.h"
   2 #include "dir.h"
   3 #include "iterator.h"
   4 #include "dir-iterator.h"
   5 #include "string-list.h"
   6
   7 struct dir_iterator_level {
   8         DIR *dir;
   9
  10         /*
  11          * The directory entries of the current level. This list will only be
  12          * populated when the iterator is ordered. In that case, `dir` will be
  13          * set to `NULL`.
  14          */
  15         struct string_list entries;
  16         size_t entries_idx;
  17
  18         /*
  19          * The length of the directory part of path at this level
  20          * (including a trailing '/'):
  21          */
  22         size_t prefix_len;
  23 };
  24
  25 /*
  26  * The full data structure used to manage the internal directory
  27  * iteration state. It includes members that are not part of the
  28  * public interface.
  29  */
  30 struct dir_iterator_int {
  31         struct dir_iterator base;
  32
  33         /*
  34          * The number of levels currently on the stack. After the first
  35          * call to dir_iterator_begin(), if it succeeds to open the
  36          * first level's dir, this will always be at least 1. Then,
  37          * when it comes to zero the iteration is ended and this
  38          * struct is freed.
  39          */
  40         size_t levels_nr;
  41
  42         /* The number of levels that have been allocated on the stack */
  43         size_t levels_alloc;
  44
  45         /*
  46          * A stack of levels. levels[0] is the uppermost directory
  47          * that will be included in this iteration.
  48          */
  49         struct dir_iterator_level *levels;
  50
  51         /* Combination of flags for this dir-iterator */
  52         unsigned int flags;
  53 };
  54
  55 static int next_directory_entry(DIR *dir, const char *path,
  56                                 struct dirent **out)
  57 {
  58         struct dirent *de;
  59
  60 repeat:
  61         errno = 0;
  62         de = readdir(dir);
  63         if (!de) {
  64                 if (errno) {
  65                         warning_errno("error reading directory '%s'",
  66                                       path);
  67                         return -1;
  68                 }
  69
  70                 return 1;
  71         }
  72
  73         if (is_dot_or_dotdot(de->d_name))
  74                 goto repeat;
  75
  76         *out = de;
  77         return 0;
  78 }
  79
  80 /*
  81  * Push a level in the iter stack and initialize it with information from
  82  * the directory pointed by iter->base->path. It is assumed that this
  83  * strbuf points to a valid directory path. Return 0 on success and -1
  84  * otherwise, setting errno accordingly and leaving the stack unchanged.
  85  */
  86 static int push_level(struct dir_iterator_int *iter)
  87 {
  88         struct dir_iterator_level *level;
  89
  90         ALLOC_GROW(iter->levels, iter->levels_nr + 1, iter->levels_alloc);
  91         level = &iter->levels[iter->levels_nr++];
  92
  93         if (!is_dir_sep(iter->base.path.buf[iter->base.path.len - 1]))
  94                 strbuf_addch(&iter->base.path, '/');
  95         level->prefix_len = iter->base.path.len;
  96
  97         level->dir = opendir(iter->base.path.buf);
  98         if (!level->dir) {
  99                 int saved_errno = errno;
 100                 if (errno != ENOENT) {
 101                         warning_errno("error opening directory '%s'",
 102                                       iter->base.path.buf);
 103                 }
 104                 iter->levels_nr--;
 105                 errno = saved_errno;
 106                 return -1;
 107         }
 108
 109         string_list_init_dup(&level->entries);
 110         level->entries_idx = 0;
 111
 112         /*
 113          * When the iterator is sorted we read and sort all directory entries
 114          * directly.
 115          */
 116         if (iter->flags & DIR_ITERATOR_SORTED) {
 117                 struct dirent *de;
 118
 119                 while (1) {
 120                         int ret = next_directory_entry(level->dir, iter->base.path.buf, &de);
 121                         if (ret < 0) {
 122                                 if (errno != ENOENT &&
 123                                     iter->flags & DIR_ITERATOR_PEDANTIC)
 124                                         return -1;
 125                                 continue;
 126                         } else if (ret > 0) {
 127                                 break;
 128                         }
 129
 130                         string_list_append(&level->entries, de->d_name);
 131                 }
 132                 string_list_sort(&level->entries);
 133
 134                 closedir(level->dir);
 135                 level->dir = NULL;
 136         }
 137
 138         return 0;
 139 }
 140
 141 /*
 142  * Pop the top level on the iter stack, releasing any resources associated
 143  * with it. Return the new value of iter->levels_nr.
 144  */
 145 static int pop_level(struct dir_iterator_int *iter)
 146 {
 147         struct dir_iterator_level *level =
 148                 &iter->levels[iter->levels_nr - 1];
 149
 150         if (level->dir && closedir(level->dir))
 151                 warning_errno("error closing directory '%s'",
 152                               iter->base.path.buf);
 153         level->dir = NULL;
 154         string_list_clear(&level->entries, 0);
 155
 156         return --iter->levels_nr;
 157 }
 158
 159 /*
 160  * Populate iter->base with the necessary information on the next iteration
 161  * entry, represented by the given name. Return 0 on success and -1
 162  * otherwise, setting errno accordingly.
 163  */
 164 static int prepare_next_entry_data(struct dir_iterator_int *iter,
 165                                    const char *name)
 166 {
 167         int err, saved_errno;
 168
 169         strbuf_addstr(&iter->base.path, name);
 170         /*
 171          * We have to reset these because the path strbuf might have
 172          * been realloc()ed at the previous strbuf_addstr().
 173          */
 174         iter->base.relative_path = iter->base.path.buf +
 175                                    iter->levels[0].prefix_len;
 176         iter->base.basename = iter->base.path.buf +
 177                               iter->levels[iter->levels_nr - 1].prefix_len;
 178
 179         err = lstat(iter->base.path.buf, &iter->base.st);
 180
 181         saved_errno = errno;
 182         if (err && errno != ENOENT)
 183                 warning_errno("failed to stat '%s'", iter->base.path.buf);
 184
 185         errno = saved_errno;
 186         return err;
 187 }
 188
 189 int dir_iterator_advance(struct dir_iterator *dir_iterator)
 190 {
 191         struct dir_iterator_int *iter =
 192                 (struct dir_iterator_int *)dir_iterator;
 193
 194         if (S_ISDIR(iter->base.st.st_mode) && push_level(iter)) {
 195                 if (errno != ENOENT && iter->flags & DIR_ITERATOR_PEDANTIC)
 196                         goto error_out;
 197                 if (iter->levels_nr == 0)
 198                         goto error_out;
 199         }
 200
 201         /* Loop until we find an entry that we can give back to the caller. */
 202         while (1) {
 203                 struct dirent *de;
 204                 struct dir_iterator_level *level =
 205                         &iter->levels[iter->levels_nr - 1];
 206                 const char *name;
 207
 208                 strbuf_setlen(&iter->base.path, level->prefix_len);
 209
 210                 if (level->dir) {
 211                         int ret = next_directory_entry(level->dir, iter->base.path.buf, &de);
 212                         if (ret < 0) {
 213                                 if (iter->flags & DIR_ITERATOR_PEDANTIC)
 214                                         goto error_out;
 215                                 continue;
 216                         } else if (ret > 0) {
 217                                 if (pop_level(iter) == 0)
 218                                         return dir_iterator_abort(dir_iterator);
 219                                 continue;
 220                         }
 221
 222                         name = de->d_name;
 223                 } else {
 224                         if (level->entries_idx >= level->entries.nr) {
 225                                 if (pop_level(iter) == 0)
 226                                         return dir_iterator_abort(dir_iterator);
 227                                 continue;
 228                         }
 229
 230                         name = level->entries.items[level->entries_idx++].string;
 231                 }
 232
 233                 if (prepare_next_entry_data(iter, name)) {
 234                         if (errno != ENOENT && iter->flags & DIR_ITERATOR_PEDANTIC)
 235                                 goto error_out;
 236                         continue;
 237                 }
 238
 239                 return ITER_OK;
 240         }
 241
 242 error_out:
 243         dir_iterator_abort(dir_iterator);
 244         return ITER_ERROR;
 245 }
 246
 247 int dir_iterator_abort(struct dir_iterator *dir_iterator)
 248 {
 249         struct dir_iterator_int *iter = (struct dir_iterator_int *)dir_iterator;
 250
 251         for (; iter->levels_nr; iter->levels_nr--) {
 252                 struct dir_iterator_level *level =
 253                         &iter->levels[iter->levels_nr - 1];
 254
 255                 if (level->dir && closedir(level->dir)) {
 256                         int saved_errno = errno;
 257                         strbuf_setlen(&iter->base.path, level->prefix_len);
 258                         errno = saved_errno;
 259                         warning_errno("error closing directory '%s'",
 260                                       iter->base.path.buf);
 261                 }
 262
 263                 string_list_clear(&level->entries, 0);
 264         }
 265
 266         free(iter->levels);
 267         strbuf_release(&iter->base.path);
 268         free(iter);
 269         return ITER_DONE;
 270 }
 271
 272 struct dir_iterator *dir_iterator_begin(const char *path, unsigned int flags)
 273 {
 274         struct dir_iterator_int *iter = xcalloc(1, sizeof(*iter));
 275         struct dir_iterator *dir_iterator = &iter->base;
 276         int saved_errno, err;
 277
 278         strbuf_init(&iter->base.path, PATH_MAX);
 279         strbuf_addstr(&iter->base.path, path);
 280
 281         ALLOC_GROW(iter->levels, 10, iter->levels_alloc);
 282         iter->levels_nr = 0;
 283         iter->flags = flags;
 284
 285         /*
 286          * Note: lstat already checks for NULL or empty strings and
 287          * nonexistent paths.
 288          */
 289         err = lstat(iter->base.path.buf, &iter->base.st);
 290
 291         if (err < 0) {
 292                 saved_errno = errno;
 293                 goto error_out;
 294         }
 295
 296         if (!S_ISDIR(iter->base.st.st_mode)) {
 297                 saved_errno = ENOTDIR;
 298                 goto error_out;
 299         }
 300
 301         return dir_iterator;
 302
 303 error_out:
 304         dir_iterator_abort(dir_iterator);
 305         errno = saved_errno;
 306         return NULL;
 307 }