dir-iterator.h

   1 #ifndef DIR_ITERATOR_H
   2 #define DIR_ITERATOR_H
   3
   4 #include "strbuf.h"
   5
   6 /*
   7  * Iterate over a directory tree.
   8  *
   9  * Iterate over a directory tree, recursively, including paths of all
  10  * types and hidden paths. Skip "." and ".." entries and don't follow
  11  * symlinks except for the original path. Note that the original path
  12  * is not included in the iteration.
  13  *
  14  * Every time dir_iterator_advance() is called, update the members of
  15  * the dir_iterator structure to reflect the next path in the
  16  * iteration. The order that paths are iterated over within a
  17  * directory is undefined, directory paths are always given before
  18  * their contents.
  19  *
  20  * A typical iteration looks like this:
  21  *
  22  *     int ok;
  23  *     unsigned int flags = DIR_ITERATOR_PEDANTIC;
  24  *     struct dir_iterator *iter = dir_iterator_begin(path, flags);
  25  *
  26  *     if (!iter)
  27  *             goto error_handler;
  28  *
  29  *     while ((ok = dir_iterator_advance(iter)) == ITER_OK) {
  30  *             if (want_to_stop_iteration()) {
  31  *                     ok = dir_iterator_abort(iter);
  32  *                     break;
  33  *             }
  34  *
  35  *             // Access information about the current path:
  36  *             if (S_ISDIR(iter->st.st_mode))
  37  *                     printf("%s is a directory\n", iter->relative_path);
  38  *     }
  39  *
  40  *     if (ok != ITER_DONE)
  41  *             handle_error();
  42  *
  43  * Callers are allowed to modify iter->path while they are working,
  44  * but they must restore it to its original contents before calling
  45  * dir_iterator_advance() again.
  46  */
  47
  48 /*
  49  * Flags for dir_iterator_begin:
  50  *
  51  * - DIR_ITERATOR_PEDANTIC: override dir-iterator's default behavior
  52  *   in case of an error at dir_iterator_advance(), which is to keep
  53  *   looking for a next valid entry. With this flag, resources are freed
  54  *   and ITER_ERROR is returned immediately. In both cases, a meaningful
  55  *   warning is emitted. Note: ENOENT errors are always ignored so that
  56  *   the API users may remove files during iteration.
  57  *
  58  * - DIR_ITERATOR_SORTED: sort directory entries alphabetically.
  59  */
  60 #define DIR_ITERATOR_PEDANTIC (1 << 0)
  61 #define DIR_ITERATOR_SORTED   (1 << 1)
  62
  63 struct dir_iterator {
  64         /* The current path: */
  65         struct strbuf path;
  66
  67         /*
  68          * The current path relative to the starting path. This part
  69          * of the path always uses "/" characters to separate path
  70          * components:
  71          */
  72         const char *relative_path;
  73
  74         /* The current basename: */
  75         const char *basename;
  76
  77         /*
  78          * The result of calling lstat() on path.
  79          */
  80         struct stat st;
  81 };
  82
  83 /*
  84  * Start a directory iteration over path with the combination of
  85  * options specified by flags. On success, return a dir_iterator
  86  * that holds the internal state of the iteration. In case of
  87  * failure, return NULL and set errno accordingly.
  88  *
  89  * The iteration includes all paths under path, not including path
  90  * itself and not including "." or ".." entries.
  91  *
  92  * Parameters are:
  93  *  - path is the starting directory. An internal copy will be made.
  94  *  - flags is a combination of the possible flags to initialize a
  95  *    dir-iterator or 0 for default behavior.
  96  */
  97 struct dir_iterator *dir_iterator_begin(const char *path, unsigned int flags);
  98
  99 /*
 100  * Advance the iterator to the first or next item and return ITER_OK.
 101  * If the iteration is exhausted, free the dir_iterator and any
 102  * resources associated with it and return ITER_DONE.
 103  *
 104  * It is a bug to use iterator or call this function again after it
 105  * has returned ITER_DONE or ITER_ERROR (which may be returned iff
 106  * the DIR_ITERATOR_PEDANTIC flag was set).
 107  */
 108 int dir_iterator_advance(struct dir_iterator *iterator);
 109
 110 /*
 111  * End the iteration before it has been exhausted. Free the
 112  * dir_iterator and any associated resources and return ITER_DONE. On
 113  * error, free the dir_iterator and return ITER_ERROR.
 114  */
 115 int dir_iterator_abort(struct dir_iterator *iterator);
 116
 117 #endif