dir-iterator.c

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