Function convert_to_sparse

sparse-index.c:201–258

}

int convert_to_sparse(struct index_state *istate, int flags)
{
	/*
	 * If the index is already sparse, empty, or otherwise
	 * cannot be converted to sparse, do not convert.
	 */
	if (istate->sparse_index == INDEX_COLLAPSED || !istate->cache_nr ||
	    !is_sparse_index_allowed(istate, flags))
		return 0;

	/*
	 * If we are purposefully collapsing a full index, then don't give
	 * advice when it is expanded later.
	 */
	give_advice_on_expansion = 0;

	/*
	 * NEEDSWORK: If we have unmerged entries, then stay full.
	 * Unmerged entries prevent the cache-tree extension from working.
	 */
	if (index_has_unmerged_entries(istate))
		return 0;

	if (!cache_tree_fully_valid(istate->cache_tree)) {
		/* Clear and recompute the cache-tree */
		cache_tree_free(&istate->cache_tree);

		/*
		 * Silently return if there is a problem with the cache tree update,
		 * which might just be due to a conflict state in some entry.
		 *
		 * This might create new tree objects, so be sure to use
		 * WRITE_TREE_MISSING_OK.
		 */
		if (cache_tree_update(istate, WRITE_TREE_MISSING_OK))
			return 0;
	}

	remove_fsmonitor(istate);

	trace2_region_enter("index", "convert_to_sparse", istate->repo);
	istate->cache_nr = convert_to_sparse_rec(istate,
						 0, 0, istate->cache_nr,
						 "", 0, istate->cache_tree);

	/* Clear and recompute the cache-tree */
	cache_tree_free(&istate->cache_tree);
	cache_tree_update(istate, 0);

	istate->fsmonitor_has_run_once = 0;
	ewah_free(istate->fsmonitor_dirty);
	istate->fsmonitor_dirty = NULL;
	FREE_AND_NULL(istate->fsmonitor_last_update);

	istate->sparse_index = INDEX_COLLAPSED;
	trace2_region_leave("index", "convert_to_sparse", istate->repo);
	return 0;
}