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
  43 /*
  44  * Push a level in the iter stack and initialize it with information from
  45  * the directory pointed by iter->base->path. It is assumed that this
  46  * strbuf points to a valid directory path. Return 0 on success and -1
  47  * otherwise, leaving the stack unchanged.
  48  */
  49 static int push_level(struct dir_iterator_int *iter)
  50 {
  51         struct dir_iterator_level *level;
  52
  53         ALLOC_GROW(iter->levels, iter->levels_nr + 1, iter->levels_alloc);
  54         level = &iter->levels[iter->levels_nr++];
  55
  56         if (!is_dir_sep(iter->base.path.buf[iter->base.path.len - 1]))
  57                 strbuf_addch(&iter->base.path, '/');
  58         level->prefix_len = iter->base.path.len;
  59
  60         level->dir = opendir(iter->base.path.buf);
  61         if (!level->dir) {
  62                 if (errno != ENOENT) {
  63                         warning_errno("error opening directory '%s'",
  64                                       iter->base.path.buf);
  65                 }
  66                 iter->levels_nr--;
  67                 return -1;
  68         }
  69
  70         return 0;
  71 }
  72
  73 /*
  74  * Pop the top level on the iter stack, releasing any resources associated
  75  * with it. Return the new value of iter->levels_nr.
  76  */
  77 static int pop_level(struct dir_iterator_int *iter)
  78 {
  79         struct dir_iterator_level *level =
  80                 &iter->levels[iter->levels_nr - 1];
  81
  82         if (level->dir && closedir(level->dir))
  83                 warning_errno("error closing directory '%s'",
  84                               iter->base.path.buf);
  85         level->dir = NULL;
  86
  87         return --iter->levels_nr;
  88 }
  89
  90 /*
  91  * Populate iter->base with the necessary information on the next iteration
  92  * entry, represented by the given dirent de. Return 0 on success and -1
  93  * otherwise.
  94  */
  95 static int prepare_next_entry_data(struct dir_iterator_int *iter,
  96                                    struct dirent *de)
  97 {
  98         strbuf_addstr(&iter->base.path, de->d_name);
  99         /*
 100          * We have to reset these because the path strbuf might have
 101          * been realloc()ed at the previous strbuf_addstr().
 102          */
 103         iter->base.relative_path = iter->base.path.buf +
 104                                    iter->levels[0].prefix_len;
 105         iter->base.basename = iter->base.path.buf +
 106                               iter->levels[iter->levels_nr - 1].prefix_len;
 107
 108         if (lstat(iter->base.path.buf, &iter->base.st)) {
 109                 if (errno != ENOENT)
 110                         warning_errno("failed to stat '%s'", iter->base.path.buf);
 111                 return -1;
 112         }
 113
 114         return 0;
 115 }
 116
 117 int dir_iterator_advance(struct dir_iterator *dir_iterator)
 118 {
 119         struct dir_iterator_int *iter =
 120                 (struct dir_iterator_int *)dir_iterator;
 121
 122         if (S_ISDIR(iter->base.st.st_mode)) {
 123                 if (push_level(iter) && iter->levels_nr == 0) {
 124                         /* Pushing the first level failed */
 125                         return dir_iterator_abort(dir_iterator);
 126                 }
 127         }
 128
 129         /* Loop until we find an entry that we can give back to the caller. */
 130         while (1) {
 131                 struct dirent *de;
 132                 struct dir_iterator_level *level =
 133                         &iter->levels[iter->levels_nr - 1];
 134
 135                 strbuf_setlen(&iter->base.path, level->prefix_len);
 136                 errno = 0;
 137                 de = readdir(level->dir);
 138
 139                 if (!de) {
 140                         if (errno)
 141                                 warning_errno("error reading directory '%s'",
 142                                               iter->base.path.buf);
 143                         else if (pop_level(iter) == 0)
 144                                 return dir_iterator_abort(dir_iterator);
 145                         continue;
 146                 }
 147
 148                 if (is_dot_or_dotdot(de->d_name))
 149                         continue;
 150
 151                 if (prepare_next_entry_data(iter, de))
 152                         continue;
 153
 154                 return ITER_OK;
 155         }
 156 }
 157
 158 int dir_iterator_abort(struct dir_iterator *dir_iterator)
 159 {
 160         struct dir_iterator_int *iter = (struct dir_iterator_int *)dir_iterator;
 161
 162         for (; iter->levels_nr; iter->levels_nr--) {
 163                 struct dir_iterator_level *level =
 164                         &iter->levels[iter->levels_nr - 1];
 165
 166                 if (level->dir && closedir(level->dir)) {
 167                         int saved_errno = errno;
 168                         strbuf_setlen(&iter->base.path, level->prefix_len);
 169                         errno = saved_errno;
 170                         warning_errno("error closing directory '%s'",
 171                                       iter->base.path.buf);
 172                 }
 173         }
 174
 175         free(iter->levels);
 176         strbuf_release(&iter->base.path);
 177         free(iter);
 178         return ITER_DONE;
 179 }
 180
 181 struct dir_iterator *dir_iterator_begin(const char *path)
 182 {
 183         struct dir_iterator_int *iter = xcalloc(1, sizeof(*iter));
 184         struct dir_iterator *dir_iterator = &iter->base;
 185         int saved_errno;
 186
 187         strbuf_init(&iter->base.path, PATH_MAX);
 188         strbuf_addstr(&iter->base.path, path);
 189
 190         ALLOC_GROW(iter->levels, 10, iter->levels_alloc);
 191         iter->levels_nr = 0;
 192
 193         /*
 194          * Note: stat already checks for NULL or empty strings and
 195          * inexistent paths.
 196          */
 197         if (stat(iter->base.path.buf, &iter->base.st) < 0) {
 198                 saved_errno = errno;
 199                 goto error_out;
 200         }
 201
 202         if (!S_ISDIR(iter->base.st.st_mode)) {
 203                 saved_errno = ENOTDIR;
 204                 goto error_out;
 205         }
 206
 207         return dir_iterator;
 208
 209 error_out:
 210         dir_iterator_abort(dir_iterator);
 211         errno = saved_errno;
 212         return NULL;
 213 }