dir-iterator.c

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