Function entry_is_new_sparse_dir

unpack-trees.c:1107–1156

* Determine whether the path specified by 'p' should be unpacked as a new * sparse directory in a sparse index. A new sparse directory 'A/': * - must be outside the sparse cone. * - must not already be in the index (i.e., no index entry with name 'A/' * exists). * - must not have any child entries in the index (i.e., no index entry * 'A/ ' exists). * If 'p' meets the above req

 * If 'p' meets the above requirements, return 1; otherwise, return 0.
 */
static int entry_is_new_sparse_dir(const struct traverse_info *info,
				   const struct name_entry *p)
{
	int res, pos;
	struct strbuf dirpath = STRBUF_INIT;
	struct unpack_trees_options *o = info->data;

	if (!S_ISDIR(p->mode))
		return 0;

	/*
	 * If the path is inside the sparse cone, it can't be a sparse directory.
	 */
	strbuf_add(&dirpath, info->traverse_path, info->pathlen);
	strbuf_add(&dirpath, p->path, p->pathlen);
	strbuf_addch(&dirpath, '/');
	if (path_in_cone_mode_sparse_checkout(dirpath.buf, o->src_index)) {
		res = 0;
		goto cleanup;
	}

	pos = index_name_pos_sparse(o->src_index, dirpath.buf, dirpath.len);
	if (pos >= 0) {
		/* Path is already in the index, not a new sparse dir */
		res = 0;
		goto cleanup;
	}

	/* Where would this sparse dir be inserted into the index? */
	pos = -pos - 1;
	if (pos >= o->src_index->cache_nr) {
		/*
		 * Sparse dir would be inserted at the end of the index, so we
		 * know it has no child entries.
		 */
		res = 1;
		goto cleanup;
	}

	/*
	 * If the dir has child entries in the index, the first would be at the
	 * position the sparse directory would be inserted. If the entry at this
	 * position is inside the dir, not a new sparse dir.
	 */
	res = strncmp(o->src_index->cache[pos]->name, dirpath.buf, dirpath.len);

cleanup:
	strbuf_release(&dirpath);
	return res;
}

/*
 * Note that traverse_by_cache_tree() duplicates some logic in this function