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         err = lstat(iter->base.path.buf, &iter->base.st);
 117
 118         saved_errno = errno;
 119         if (err && errno != ENOENT)
 120                 warning_errno("failed to stat '%s'", iter->base.path.buf);
 121
 122         errno = saved_errno;
 123         return err;
 124 }
 125
 126 int dir_iterator_advance(struct dir_iterator *dir_iterator)
 127 {
 128         struct dir_iterator_int *iter =
 129                 (struct dir_iterator_int *)dir_iterator;
 130
 131         if (S_ISDIR(iter->base.st.st_mode) && push_level(iter)) {
 132                 if (errno != ENOENT && iter->flags & DIR_ITERATOR_PEDANTIC)
 133                         goto error_out;
 134                 if (iter->levels_nr == 0)
 135                         goto error_out;
 136         }
 137
 138         /* Loop until we find an entry that we can give back to the caller. */
 139         while (1) {
 140                 struct dirent *de;
 141                 struct dir_iterator_level *level =
 142                         &iter->levels[iter->levels_nr - 1];
 143
 144                 strbuf_setlen(&iter->base.path, level->prefix_len);
 145                 errno = 0;
 146                 de = readdir(level->dir);
 147
 148                 if (!de) {
 149                         if (errno) {
 150                                 warning_errno("error reading directory '%s'",
 151                                               iter->base.path.buf);
 152                                 if (iter->flags & DIR_ITERATOR_PEDANTIC)
 153                                         goto error_out;
 154                         } else if (pop_level(iter) == 0) {
 155                                 return dir_iterator_abort(dir_iterator);
 156                         }
 157                         continue;
 158                 }
 159
 160                 if (is_dot_or_dotdot(de->d_name))
 161                         continue;
 162
 163                 if (prepare_next_entry_data(iter, de)) {
 164                         if (errno != ENOENT && iter->flags & DIR_ITERATOR_PEDANTIC)
 165                                 goto error_out;
 166                         continue;
 167                 }
 168
 169                 return ITER_OK;
 170         }
 171
 172 error_out:
 173         dir_iterator_abort(dir_iterator);
 174         return ITER_ERROR;
 175 }
 176
 177 int dir_iterator_abort(struct dir_iterator *dir_iterator)
 178 {
 179         struct dir_iterator_int *iter = (struct dir_iterator_int *)dir_iterator;
 180
 181         for (; iter->levels_nr; iter->levels_nr--) {
 182                 struct dir_iterator_level *level =
 183                         &iter->levels[iter->levels_nr - 1];
 184
 185                 if (level->dir && closedir(level->dir)) {
 186                         int saved_errno = errno;
 187                         strbuf_setlen(&iter->base.path, level->prefix_len);
 188                         errno = saved_errno;
 189                         warning_errno("error closing directory '%s'",
 190                                       iter->base.path.buf);
 191                 }
 192         }
 193
 194         free(iter->levels);
 195         strbuf_release(&iter->base.path);
 196         free(iter);
 197         return ITER_DONE;
 198 }
 199
 200 struct dir_iterator *dir_iterator_begin(const char *path, unsigned int flags)
 201 {
 202         struct dir_iterator_int *iter = xcalloc(1, sizeof(*iter));
 203         struct dir_iterator *dir_iterator = &iter->base;
 204         int saved_errno, err;
 205
 206         strbuf_init(&iter->base.path, PATH_MAX);
 207         strbuf_addstr(&iter->base.path, path);
 208
 209         ALLOC_GROW(iter->levels, 10, iter->levels_alloc);
 210         iter->levels_nr = 0;
 211         iter->flags = flags;
 212
 213         /*
 214          * Note: lstat already checks for NULL or empty strings and
 215          * nonexistent paths.
 216          */
 217         err = lstat(iter->base.path.buf, &iter->base.st);
 218
 219         if (err < 0) {
 220                 saved_errno = errno;
 221                 goto error_out;
 222         }
 223
 224         if (!S_ISDIR(iter->base.st.st_mode)) {
 225                 saved_errno = ENOTDIR;
 226                 goto error_out;
 227         }
 228
 229         return dir_iterator;
 230
 231 error_out:
 232         dir_iterator_abort(dir_iterator);
 233         errno = saved_errno;
 234         return NULL;
 235 }