/*! \brief Rewinds the directory iterator.
\return
- \c B_OK: Everything went fine.
- \c B_PERMISSION_DENIED: Directory permissions didn't allow operation.
- \c B_NO_MEMORY: Insufficient memory for operation.
- \c B_LINK_LIMIT: Indicates a cyclic loop within the file system.
- \c B_BUSY: A node was busy.
- \c B_FILE_ERROR: A general file error.
- \c B_NO_MORE_FDS: The application has run out of file descriptors.
\see GetNextEntry(), GetNextRef(), GetNextDirents(), CountEntries()
*/
status_t
BDirectory::Rewind()
{
if (InitCheck() != B_OK)
return B_FILE_ERROR;
return _kern_rewind_dir(fDirFd);
}
/*! \brief Resets the object's attribute pointer to the first attribute in the
list.
\return
- \c B_OK: Everything went fine.
- \c B_FILE_ERROR: Some error occured.
*/
status_t
BNode::RewindAttrs()
{
if (InitAttrDir() != B_OK)
return B_FILE_ERROR;
return _kern_rewind_dir(fAttrFd);
}
static int
do_seek_dir(DIR* dir)
{
if (dir->seek_position == dir->current_position)
return 0;
// If the seek position lies before the current position (the usual case),
// rewind to the beginning.
if (dir->seek_position < dir->current_position) {
status_t status = _kern_rewind_dir(dir->fd);
if (status < 0) {
__set_errno(status);
return -1;
}
dir->current_position = 0;
dir->entries_left = 0;
}
// Now skip entries until we have reached seek_position.
while (dir->seek_position > dir->current_position) {
ssize_t count;
long toSkip = dir->seek_position - dir->current_position;
if (toSkip == dir->entries_left) {
// we have to skip exactly all of the currently buffered entries
dir->current_position = dir->seek_position;
dir->entries_left = 0;
return 0;
}
if (toSkip < dir->entries_left) {
// we have to skip only some of the buffered entries
for (; toSkip > 0; toSkip--) {
struct dirent* entry = (struct dirent*)
((uint8*)&dir->first_entry + dir->next_entry);
dir->entries_left--;
dir->next_entry += entry->d_reclen;
}
dir->current_position = dir->seek_position;
return 0;
}
// we have to skip more than the currently buffered entries
dir->current_position += dir->entries_left;
dir->entries_left = 0;
count = _kern_read_dir(dir->fd, &dir->first_entry,
(char*)dir + DIR_BUFFER_SIZE - (char*)&dir->first_entry, USHRT_MAX);
if (count <= 0) {
if (count < 0)
__set_errno(count);
// end of directory
return -1;
}
dir->next_entry = 0;
dir->entries_left = count;
}
return 0;
}
