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         err = lstat(iter->base.path.buf, &iter->base.st);
 116
 117         saved_errno = errno;
 118         if (err && errno != ENOENT)
 119                 warning_errno("failed to stat '%s'", iter->base.path.buf);
 120
 121         errno = saved_errno;
 122         return err;
 123 }
 124
 125 int dir_iterator_advance(struct dir_iterator *dir_iterator)
 126 {
 127         struct dir_iterator_int *iter =
 128                 (struct dir_iterator_int *)dir_iterator;
 129
 130         if (S_ISDIR(iter->base.st.st_mode) && push_level(iter)) {
 131                 if (errno != ENOENT && iter->flags & DIR_ITERATOR_PEDANTIC)
 132                         goto error_out;
 133                 if (iter->levels_nr == 0)
 134                         goto error_out;
 135         }
 136
 137         /* Loop until we find an entry that we can give back to the caller. */
 138         while (1) {
 139                 struct dirent *de;
 140                 struct dir_iterator_level *level =
 141                         &iter->levels[iter->levels_nr - 1];
 142
 143                 strbuf_setlen(&iter->base.path, level->prefix_len);
 144                 errno = 0;
 145                 de = readdir(level->dir);
 146
 147                 if (!de) {
 148                         if (errno) {
 149                                 warning_errno("error reading directory '%s'",
 150                                               iter->base.path.buf);
 151                                 if (iter->flags & DIR_ITERATOR_PEDANTIC)
 152                                         goto error_out;
 153                         } else if (pop_level(iter) == 0) {
 154                                 return dir_iterator_abort(dir_iterator);
 155                         }
 156                         continue;
 157                 }
 158
 159                 if (is_dot_or_dotdot(de->d_name))
 160                         continue;
 161
 162                 if (prepare_next_entry_data(iter, de)) {
 163                         if (errno != ENOENT && iter->flags & DIR_ITERATOR_PEDANTIC)
 164                                 goto error_out;
 165                         continue;
 166                 }
 167
 168                 return ITER_OK;
 169         }
 170
 171 error_out:
 172         dir_iterator_abort(dir_iterator);
 173         return ITER_ERROR;
 174 }
 175
 176 int dir_iterator_abort(struct dir_iterator *dir_iterator)
 177 {
 178         struct dir_iterator_int *iter = (struct dir_iterator_int *)dir_iterator;
 179
 180         for (; iter->levels_nr; iter->levels_nr--) {
 181                 struct dir_iterator_level *level =
 182                         &iter->levels[iter->levels_nr - 1];
 183
 184                 if (level->dir && closedir(level->dir)) {
 185                         int saved_errno = errno;
 186                         strbuf_setlen(&iter->base.path, level->prefix_len);
 187                         errno = saved_errno;
 188                         warning_errno("error closing directory '%s'",
 189                                       iter->base.path.buf);
 190                 }
 191         }
 192
 193         free(iter->levels);
 194         strbuf_release(&iter->base.path);
 195         free(iter);
 196         return ITER_DONE;
 197 }
 198
 199 struct dir_iterator *dir_iterator_begin(const char *path, unsigned int flags)
 200 {
 201         struct dir_iterator_int *iter = xcalloc(1, sizeof(*iter));
 202         struct dir_iterator *dir_iterator = &iter->base;
 203         int saved_errno, err;
 204
 205         strbuf_init(&iter->base.path, PATH_MAX);
 206         strbuf_addstr(&iter->base.path, path);
 207
 208         ALLOC_GROW(iter->levels, 10, iter->levels_alloc);
 209         iter->levels_nr = 0;
 210         iter->flags = flags;
 211
 212         /*
 213          * Note: lstat already checks for NULL or empty strings and
 214          * nonexistent paths.
 215          */
 216         err = lstat(iter->base.path.buf, &iter->base.st);
 217
 218         if (err < 0) {
 219                 saved_errno = errno;
 220                 goto error_out;
 221         }
 222
 223         if (!S_ISDIR(iter->base.st.st_mode)) {
 224                 saved_errno = ENOTDIR;
 225                 goto error_out;
 226         }
 227
 228         return dir_iterator;
 229
 230 error_out:
 231         dir_iterator_abort(dir_iterator);
 232         errno = saved_errno;
 233         return NULL;
 234 }