Function update_index_from_diff

builtin/reset.c:151–195

}

static void update_index_from_diff(struct diff_queue_struct *q,
				   struct diff_options *opt UNUSED,
				   void *data)
{
	int i;
	int intent_to_add = *(int *)data;

	for (i = 0; i < q->nr; i++) {
		int pos;
		struct diff_filespec *one = q->queue[i]->one;
		int is_in_reset_tree = one->mode && !is_null_oid(&one->oid);
		struct cache_entry *ce;

		if (!is_in_reset_tree && !intent_to_add) {
			remove_file_from_index(the_repository->index, one->path);
			continue;
		}

		ce = make_cache_entry(the_repository->index, one->mode, &one->oid, one->path,
				      0, 0);

		/*
		 * If the file 1) corresponds to an existing index entry with
		 * skip-worktree set, or 2) does not exist in the index but is
		 * outside the sparse checkout definition, add a skip-worktree bit
		 * to the new index entry. Note that a sparse index will be expanded
		 * if this entry is outside the sparse cone - this is necessary
		 * to properly construct the reset sparse directory.
		 */
		pos = index_name_pos(the_repository->index, one->path, strlen(one->path));
		if ((pos >= 0 && ce_skip_worktree(the_repository->index->cache[pos])) ||
		    (pos < 0 && !path_in_sparse_checkout(one->path, the_repository->index)))
			ce->ce_flags |= CE_SKIP_WORKTREE;

		if (!ce)
			die(_("make_cache_entry failed for path '%s'"),
			    one->path);
		if (!is_in_reset_tree) {
			ce->ce_flags |= CE_INTENT_TO_ADD;
			set_object_name_for_intent_to_add_entry(ce);
		}
		add_index_entry(the_repository->index, ce,
				ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
	}
}

static int read_from_tree(const struct pathspec *pathspec,
			  struct object_id *tree_oid,