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         int initialized;
   8
   9         DIR *dir;
  10
  11         /*
  12          * The length of the directory part of path at this level
  13          * (including a trailing '/'):
  14          */
  15         size_t prefix_len;
  16
  17         /*
  18          * The last action that has been taken with the current entry
  19          * (needed for directories, which have to be included in the
  20          * iteration and also iterated into):
  21          */
  22         enum {
  23                 DIR_STATE_ITER,
  24                 DIR_STATE_RECURSE
  25         } dir_state;
  26 };
  27
  28 /*
  29  * The full data structure used to manage the internal directory
  30  * iteration state. It includes members that are not part of the
  31  * public interface.
  32  */
  33 struct dir_iterator_int {
  34         struct dir_iterator base;
  35
  36         /*
  37          * The number of levels currently on the stack. This is always
  38          * at least 1, because when it becomes zero the iteration is
  39          * ended and this struct is freed.
  40          */
  41         size_t levels_nr;
  42
  43         /* The number of levels that have been allocated on the stack */
  44         size_t levels_alloc;
  45
  46         /*
  47          * A stack of levels. levels[0] is the uppermost directory
  48          * that will be included in this iteration.
  49          */
  50         struct dir_iterator_level *levels;
  51 };
  52
  53 int dir_iterator_advance(struct dir_iterator *dir_iterator)
  54 {
  55         struct dir_iterator_int *iter =
  56                 (struct dir_iterator_int *)dir_iterator;
  57
  58         while (1) {
  59                 struct dir_iterator_level *level =
  60                         &iter->levels[iter->levels_nr - 1];
  61                 struct dirent *de;
  62
  63                 if (!level->initialized) {
  64                         /*
  65                          * Note: dir_iterator_begin() ensures that
  66                          * path is not the empty string.
  67                          */
  68                         if (!is_dir_sep(iter->base.path.buf[iter->base.path.len - 1]))
  69                                 strbuf_addch(&iter->base.path, '/');
  70                         level->prefix_len = iter->base.path.len;
  71
  72                         level->dir = opendir(iter->base.path.buf);
  73                         if (!level->dir && errno != ENOENT) {
  74                                 warning("error opening directory %s: %s",
  75                                         iter->base.path.buf, strerror(errno));
  76                                 /* Popping the level is handled below */
  77                         }
  78
  79                         level->initialized = 1;
  80                 } else if (S_ISDIR(iter->base.st.st_mode)) {
  81                         if (level->dir_state == DIR_STATE_ITER) {
  82                                 /*
  83                                  * The directory was just iterated
  84                                  * over; now prepare to iterate into
  85                                  * it.
  86                                  */
  87                                 level->dir_state = DIR_STATE_RECURSE;
  88                                 ALLOC_GROW(iter->levels, iter->levels_nr + 1,
  89                                            iter->levels_alloc);
  90                                 level = &iter->levels[iter->levels_nr++];
  91                                 level->initialized = 0;
  92                                 continue;
  93                         } else {
  94                                 /*
  95                                  * The directory has already been
  96                                  * iterated over and iterated into;
  97                                  * we're done with it.
  98                                  */
  99                         }
 100                 }
 101
 102                 if (!level->dir) {
 103                         /*
 104                          * This level is exhausted (or wasn't opened
 105                          * successfully); pop up a level.
 106                          */
 107                         if (--iter->levels_nr == 0)
 108                                 return dir_iterator_abort(dir_iterator);
 109
 110                         continue;
 111                 }
 112
 113                 /*
 114                  * Loop until we find an entry that we can give back
 115                  * to the caller:
 116                  */
 117                 while (1) {
 118                         strbuf_setlen(&iter->base.path, level->prefix_len);
 119                         errno = 0;
 120                         de = readdir(level->dir);
 121
 122                         if (!de) {
 123                                 /* This level is exhausted; pop up a level. */
 124                                 if (errno) {
 125                                         warning("error reading directory %s: %s",
 126                                                 iter->base.path.buf, strerror(errno));
 127                                 } else if (closedir(level->dir))
 128                                         warning("error closing directory %s: %s",
 129                                                 iter->base.path.buf, strerror(errno));
 130
 131                                 level->dir = NULL;
 132                                 if (--iter->levels_nr == 0)
 133                                         return dir_iterator_abort(dir_iterator);
 134                                 break;
 135                         }
 136
 137                         if (is_dot_or_dotdot(de->d_name))
 138                                 continue;
 139
 140                         strbuf_addstr(&iter->base.path, de->d_name);
 141                         if (lstat(iter->base.path.buf, &iter->base.st) < 0) {
 142                                 if (errno != ENOENT)
 143                                         warning("error reading path '%s': %s",
 144                                                 iter->base.path.buf,
 145                                                 strerror(errno));
 146                                 continue;
 147                         }
 148
 149                         /*
 150                          * We have to set these each time because
 151                          * the path strbuf might have been realloc()ed.
 152                          */
 153                         iter->base.relative_path =
 154                                 iter->base.path.buf + iter->levels[0].prefix_len;
 155                         iter->base.basename =
 156                                 iter->base.path.buf + level->prefix_len;
 157                         level->dir_state = DIR_STATE_ITER;
 158
 159                         return ITER_OK;
 160                 }
 161         }
 162 }
 163
 164 int dir_iterator_abort(struct dir_iterator *dir_iterator)
 165 {
 166         struct dir_iterator_int *iter = (struct dir_iterator_int *)dir_iterator;
 167
 168         for (; iter->levels_nr; iter->levels_nr--) {
 169                 struct dir_iterator_level *level =
 170                         &iter->levels[iter->levels_nr - 1];
 171
 172                 if (level->dir && closedir(level->dir)) {
 173                         strbuf_setlen(&iter->base.path, level->prefix_len);
 174                         warning("error closing directory %s: %s",
 175                                 iter->base.path.buf, strerror(errno));
 176                 }
 177         }
 178
 179         free(iter->levels);
 180         strbuf_release(&iter->base.path);
 181         free(iter);
 182         return ITER_DONE;
 183 }
 184
 185 struct dir_iterator *dir_iterator_begin(const char *path)
 186 {
 187         struct dir_iterator_int *iter = xcalloc(1, sizeof(*iter));
 188         struct dir_iterator *dir_iterator = &iter->base;
 189
 190         if (!path || !*path)
 191                 die("BUG: empty path passed to dir_iterator_begin()");
 192
 193         strbuf_init(&iter->base.path, PATH_MAX);
 194         strbuf_addstr(&iter->base.path, path);
 195
 196         ALLOC_GROW(iter->levels, 10, iter->levels_alloc);
 197
 198         iter->levels_nr = 1;
 199         iter->levels[0].initialized = 0;
 200
 201         return dir_iterator;
 202 }