[thirdparty/git.git] / sparse-index.c

#include "cache.h"
#include "repository.h"
#include "sparse-index.h"
#include "tree.h"
#include "pathspec.h"
#include "trace2.h"
#include "cache-tree.h"
#include "config.h"
#include "dir.h"
#include "fsmonitor.h"

static struct cache_entry *construct_sparse_dir_entry(
				struct index_state *istate,
				const char *sparse_dir,
				struct cache_tree *tree)
{
	struct cache_entry *de;

	de = make_cache_entry(istate, S_IFDIR, &tree->oid, sparse_dir, 0, 0);

	de->ce_flags |= CE_SKIP_WORKTREE;
	return de;
}

/*
 * Returns the number of entries "inserted" into the index.
 */
static int convert_to_sparse_rec(struct index_state *istate,
				 int num_converted,
				 int start, int end,
				 const char *ct_path, size_t ct_pathlen,
				 struct cache_tree *ct)
{
	int i, can_convert = 1;
	int start_converted = num_converted;
	struct strbuf child_path = STRBUF_INIT;

	/*
	 * Is the current path outside of the sparse cone?
	 * Then check if the region can be replaced by a sparse
	 * directory entry (everything is sparse and merged).
	 */
	if (path_in_sparse_checkout(ct_path, istate))
		can_convert = 0;

	for (i = start; can_convert && i < end; i++) {
		struct cache_entry *ce = istate->cache[i];

		if (ce_stage(ce) ||
		    S_ISGITLINK(ce->ce_mode) ||
		    !(ce->ce_flags & CE_SKIP_WORKTREE))
			can_convert = 0;
	}

	if (can_convert) {
		struct cache_entry *se;
		se = construct_sparse_dir_entry(istate, ct_path, ct);

		istate->cache[num_converted++] = se;
		return 1;
	}

	for (i = start; i < end; ) {
		int count, span, pos = -1;
		const char *base, *slash;
		struct cache_entry *ce = istate->cache[i];

		/*
		 * Detect if this is a normal entry outside of any subtree
		 * entry.
		 */
		base = ce->name + ct_pathlen;
		slash = strchr(base, '/');

		if (slash)
			pos = cache_tree_subtree_pos(ct, base, slash - base);

		if (pos < 0) {
			istate->cache[num_converted++] = ce;
			i++;
			continue;
		}

		strbuf_setlen(&child_path, 0);
		strbuf_add(&child_path, ce->name, slash - ce->name + 1);

		span = ct->down[pos]->cache_tree->entry_count;
		count = convert_to_sparse_rec(istate,
					      num_converted, i, i + span,
					      child_path.buf, child_path.len,
					      ct->down[pos]->cache_tree);
		num_converted += count;
		i += span;
	}

	strbuf_release(&child_path);
	return num_converted - start_converted;
}

int set_sparse_index_config(struct repository *repo, int enable)
{
	int res = repo_config_set_worktree_gently(repo,
						  "index.sparse",
						  enable ? "true" : "false");
	prepare_repo_settings(repo);
	repo->settings.sparse_index = enable;
	return res;
}

static int index_has_unmerged_entries(struct index_state *istate)
{
	int i;
	for (i = 0; i < istate->cache_nr; i++) {
		if (ce_stage(istate->cache[i]))
			return 1;
	}

	return 0;
}

static int is_sparse_index_allowed(struct index_state *istate, int flags)
{
	if (!core_apply_sparse_checkout || !core_sparse_checkout_cone)
		return 0;

	if (!istate->repo)
		istate->repo = the_repository;

	if (!(flags & SPARSE_INDEX_MEMORY_ONLY)) {
		int test_env;

		/*
		 * The sparse index is not (yet) integrated with a split index.
		 */
		if (istate->split_index || git_env_bool("GIT_TEST_SPLIT_INDEX", 0))
			return 0;
		/*
		 * The GIT_TEST_SPARSE_INDEX environment variable triggers the
		 * index.sparse config variable to be on.
		 */
		test_env = git_env_bool("GIT_TEST_SPARSE_INDEX", -1);
		if (test_env >= 0)
			set_sparse_index_config(istate->repo, test_env);

		/*
		 * Only convert to sparse if index.sparse is set.
		 */
		prepare_repo_settings(istate->repo);
		if (!istate->repo->settings.sparse_index)
			return 0;
	}

	if (init_sparse_checkout_patterns(istate))
		return 0;

	/*
	 * We need cone-mode patterns to use sparse-index. If a user edits
	 * their sparse-checkout file manually, then we can detect during
	 * parsing that they are not actually using cone-mode patterns and
	 * hence we need to abort this conversion _without error_. Warnings
	 * already exist in the pattern parsing to inform the user of their
	 * bad patterns.
	 */
	if (!istate->sparse_checkout_patterns->use_cone_patterns)
		return 0;

	return 1;
}

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 || !istate->cache_nr ||
	    !is_sparse_index_allowed(istate, flags))
		return 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;
	FREE_AND_NULL(istate->fsmonitor_dirty);
	FREE_AND_NULL(istate->fsmonitor_last_update);

	istate->sparse_index = 1;
	trace2_region_leave("index", "convert_to_sparse", istate->repo);
	return 0;
}

static void set_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
{
	ALLOC_GROW(istate->cache, nr + 1, istate->cache_alloc);

	istate->cache[nr] = ce;
	add_name_hash(istate, ce);
}

static int add_path_to_index(const struct object_id *oid,
			     struct strbuf *base, const char *path,
			     unsigned int mode, void *context)
{
	struct index_state *istate = (struct index_state *)context;
	struct cache_entry *ce;
	size_t len = base->len;

	if (S_ISDIR(mode))
		return READ_TREE_RECURSIVE;

	strbuf_addstr(base, path);

	ce = make_cache_entry(istate, mode, oid, base->buf, 0, 0);
	ce->ce_flags |= CE_SKIP_WORKTREE | CE_EXTENDED;
	set_index_entry(istate, istate->cache_nr++, ce);

	strbuf_setlen(base, len);
	return 0;
}

void ensure_full_index(struct index_state *istate)
{
	int i;
	struct index_state *full;
	struct strbuf base = STRBUF_INIT;

	if (!istate || !istate->sparse_index)
		return;

	if (!istate->repo)
		istate->repo = the_repository;

	trace2_region_enter("index", "ensure_full_index", istate->repo);

	/* initialize basics of new index */
	full = xcalloc(1, sizeof(struct index_state));
	memcpy(full, istate, sizeof(struct index_state));

	/* then change the necessary things */
	full->sparse_index = 0;
	full->cache_alloc = (3 * istate->cache_alloc) / 2;
	full->cache_nr = 0;
	ALLOC_ARRAY(full->cache, full->cache_alloc);

	for (i = 0; i < istate->cache_nr; i++) {
		struct cache_entry *ce = istate->cache[i];
		struct tree *tree;
		struct pathspec ps;

		if (!S_ISSPARSEDIR(ce->ce_mode)) {
			set_index_entry(full, full->cache_nr++, ce);
			continue;
		}
		if (!(ce->ce_flags & CE_SKIP_WORKTREE))
			warning(_("index entry is a directory, but not sparse (%08x)"),
				ce->ce_flags);

		/* recursively walk into cd->name */
		tree = lookup_tree(istate->repo, &ce->oid);

		memset(&ps, 0, sizeof(ps));
		ps.recursive = 1;
		ps.has_wildcard = 1;
		ps.max_depth = -1;

		strbuf_setlen(&base, 0);
		strbuf_add(&base, ce->name, strlen(ce->name));

		read_tree_at(istate->repo, tree, &base, &ps,
			     add_path_to_index, full);

		/* free directory entries. full entries are re-used */
		discard_cache_entry(ce);
	}

	/* Copy back into original index. */
	memcpy(&istate->name_hash, &full->name_hash, sizeof(full->name_hash));
	memcpy(&istate->dir_hash, &full->dir_hash, sizeof(full->dir_hash));
	istate->sparse_index = 0;
	free(istate->cache);
	istate->cache = full->cache;
	istate->cache_nr = full->cache_nr;
	istate->cache_alloc = full->cache_alloc;
	istate->fsmonitor_has_run_once = 0;
	FREE_AND_NULL(istate->fsmonitor_dirty);
	FREE_AND_NULL(istate->fsmonitor_last_update);

	strbuf_release(&base);
	free(full);

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

	trace2_region_leave("index", "ensure_full_index", istate->repo);
}

void ensure_correct_sparsity(struct index_state *istate)
{
	/*
	 * If the index can be sparse, make it sparse. Otherwise,
	 * ensure the index is full.
	 */
	if (is_sparse_index_allowed(istate, 0))
		convert_to_sparse(istate, 0);
	else
		ensure_full_index(istate);
}

/*
 * This static global helps avoid infinite recursion between
 * expand_to_path() and index_file_exists().
 */
static int in_expand_to_path = 0;

void expand_to_path(struct index_state *istate,
		    const char *path, size_t pathlen, int icase)
{
	struct strbuf path_mutable = STRBUF_INIT;
	size_t substr_len;

	/* prevent extra recursion */
	if (in_expand_to_path)
		return;

	if (!istate || !istate->sparse_index)
		return;

	if (!istate->repo)
		istate->repo = the_repository;

	in_expand_to_path = 1;

	/*
	 * We only need to actually expand a region if the
	 * following are both true:
	 *
	 * 1. 'path' is not already in the index.
	 * 2. Some parent directory of 'path' is a sparse directory.
	 */

	if (index_file_exists(istate, path, pathlen, icase))
		goto cleanup;

	strbuf_add(&path_mutable, path, pathlen);
	strbuf_addch(&path_mutable, '/');

	/* Check the name hash for all parent directories */
	substr_len = 0;
	while (substr_len < pathlen) {
		char temp;
		char *replace = strchr(path_mutable.buf + substr_len, '/');

		if (!replace)
			break;

		/* replace the character _after_ the slash */
		replace++;
		temp = *replace;
		*replace = '\0';
		if (index_file_exists(istate, path_mutable.buf,
				      path_mutable.len, icase)) {
			/*
			 * We found a parent directory in the name-hash
			 * hashtable, because only sparse directory entries
			 * have a trailing '/' character.  Since "path" wasn't
			 * in the index, perhaps it exists within this
			 * sparse-directory.  Expand accordingly.
			 */
			ensure_full_index(istate);
			break;
		}

		*replace = temp;
		substr_len = replace - path_mutable.buf;
	}

cleanup:
	strbuf_release(&path_mutable);
	in_expand_to_path = 0;
}
Commit	Line	Data
3964fc2a DS	1	#include "cache.h"
	2	#include "repository.h"
	3	#include "sparse-index.h"
4300f844 DS	4	#include "tree.h"
	5	#include "pathspec.h"
	6	#include "trace2.h"
6e773527 DS	7	#include "cache-tree.h"
	8	#include "config.h"
	9	#include "dir.h"
	10	#include "fsmonitor.h"
	11
	12	static struct cache_entry *construct_sparse_dir_entry(
	13	struct index_state *istate,
	14	const char *sparse_dir,
	15	struct cache_tree *tree)
	16	{
	17	struct cache_entry *de;
	18
	19	de = make_cache_entry(istate, S_IFDIR, &tree->oid, sparse_dir, 0, 0);
	20
	21	de->ce_flags \|= CE_SKIP_WORKTREE;
	22	return de;
	23	}
	24
	25	/*
	26	* Returns the number of entries "inserted" into the index.
	27	*/
	28	static int convert_to_sparse_rec(struct index_state *istate,
	29	int num_converted,
	30	int start, int end,
	31	const char *ct_path, size_t ct_pathlen,
	32	struct cache_tree *ct)
	33	{
	34	int i, can_convert = 1;
	35	int start_converted = num_converted;
6e773527	36	struct strbuf child_path = STRBUF_INIT;
6e773527 DS	37
	38	/*
	39	* Is the current path outside of the sparse cone?
	40	* Then check if the region can be replaced by a sparse
	41	* directory entry (everything is sparse and merged).
	42	*/
02155c8c	43	if (path_in_sparse_checkout(ct_path, istate))
6e773527 DS	44	can_convert = 0;
	45
	46	for (i = start; can_convert && i < end; i++) {
	47	struct cache_entry *ce = istate->cache[i];
	48
	49	if (ce_stage(ce) \|\|
f442313e	50	S_ISGITLINK(ce->ce_mode) \|\|
6e773527 DS	51	!(ce->ce_flags & CE_SKIP_WORKTREE))
	52	can_convert = 0;
	53	}
	54
	55	if (can_convert) {
	56	struct cache_entry *se;
	57	se = construct_sparse_dir_entry(istate, ct_path, ct);
	58
	59	istate->cache[num_converted++] = se;
	60	return 1;
	61	}
	62
	63	for (i = start; i < end; ) {
	64	int count, span, pos = -1;
	65	const char base, slash;
	66	struct cache_entry *ce = istate->cache[i];
	67
	68	/*
	69	* Detect if this is a normal entry outside of any subtree
	70	* entry.
	71	*/
	72	base = ce->name + ct_pathlen;
	73	slash = strchr(base, '/');
	74
	75	if (slash)
	76	pos = cache_tree_subtree_pos(ct, base, slash - base);
	77
	78	if (pos < 0) {
	79	istate->cache[num_converted++] = ce;
	80	i++;
	81	continue;
	82	}
	83
	84	strbuf_setlen(&child_path, 0);
	85	strbuf_add(&child_path, ce->name, slash - ce->name + 1);
	86
	87	span = ct->down[pos]->cache_tree->entry_count;
	88	count = convert_to_sparse_rec(istate,
	89	num_converted, i, i + span,
	90	child_path.buf, child_path.len,
	91	ct->down[pos]->cache_tree);
	92	num_converted += count;
	93	i += span;
	94	}
	95
	96	strbuf_release(&child_path);
	97	return num_converted - start_converted;
	98	}
	99
b79f9c07	100	int set_sparse_index_config(struct repository *repo, int enable)
58300f47	101	{
7316dc5f DS	102	int res = repo_config_set_worktree_gently(repo,
	103	"index.sparse",
	104	enable ? "true" : "false");
122ba1f7 DS	105	prepare_repo_settings(repo);
	106	repo->settings.sparse_index = enable;
	107	return res;
58300f47 DS	108	}
58300f47 DS	109
fc6609d1 DS	110	static int index_has_unmerged_entries(struct index_state *istate)
	111	{
	112	int i;
	113	for (i = 0; i < istate->cache_nr; i++) {
	114	if (ce_stage(istate->cache[i]))
	115	return 1;
	116	}
	117
	118	return 0;
	119	}
	120
b93fea08	121	static int is_sparse_index_allowed(struct index_state *istate, int flags)
6e773527	122	{
b93fea08	123	if (!core_apply_sparse_checkout \|\| !core_sparse_checkout_cone)
6e773527 DS	124	return 0;
6e773527 DS	125
58300f47 DS	126	if (!istate->repo)
	127	istate->repo = the_repository;
	128
ce7a9f01	129	if (!(flags & SPARSE_INDEX_MEMORY_ONLY)) {
b93fea08 VD	130	int test_env;
b93fea08 VD	131
ce7a9f01 DS	132	/*
	133	* The sparse index is not (yet) integrated with a split index.
	134	*/
ae103c37	135	if (istate->split_index \|\| git_env_bool("GIT_TEST_SPLIT_INDEX", 0))
ce7a9f01 DS	136	return 0;
	137	/*
	138	* The GIT_TEST_SPARSE_INDEX environment variable triggers the
	139	* index.sparse config variable to be on.
	140	*/
	141	test_env = git_env_bool("GIT_TEST_SPARSE_INDEX", -1);
	142	if (test_env >= 0)
	143	set_sparse_index_config(istate->repo, test_env);
6e773527	144
ce7a9f01 DS	145	/*
	146	* Only convert to sparse if index.sparse is set.
	147	*/
	148	prepare_repo_settings(istate->repo);
	149	if (!istate->repo->settings.sparse_index)
6e773527 DS	150	return 0;
	151	}
	152
02155c8c DS	153	if (init_sparse_checkout_patterns(istate))
02155c8c DS	154	return 0;
6e773527	155
e27eab45 DS	156	/*
	157	* We need cone-mode patterns to use sparse-index. If a user edits
	158	* their sparse-checkout file manually, then we can detect during
	159	* parsing that they are not actually using cone-mode patterns and
	160	* hence we need to abort this conversion _without error_. Warnings
	161	* already exist in the pattern parsing to inform the user of their
	162	* bad patterns.
	163	*/
	164	if (!istate->sparse_checkout_patterns->use_cone_patterns)
	165	return 0;
6e773527	166
b93fea08 VD	167	return 1;
	168	}
	169
	170	int convert_to_sparse(struct index_state *istate, int flags)
	171	{
	172	/*
	173	* If the index is already sparse, empty, or otherwise
	174	* cannot be converted to sparse, do not convert.
	175	*/
	176	if (istate->sparse_index \|\| !istate->cache_nr \|\|
	177	!is_sparse_index_allowed(istate, flags))
	178	return 0;
	179
fc6609d1 DS	180	/*
	181	* NEEDSWORK: If we have unmerged entries, then stay full.
	182	* Unmerged entries prevent the cache-tree extension from working.
	183	*/
	184	if (index_has_unmerged_entries(istate))
	185	return 0;
	186
13f69f30 VD	187	if (!cache_tree_fully_valid(istate->cache_tree)) {
	188	/* Clear and recompute the cache-tree */
	189	cache_tree_free(&istate->cache_tree);
	190
	191	/*
	192	* Silently return if there is a problem with the cache tree update,
	193	* which might just be due to a conflict state in some entry.
	194	*
	195	* This might create new tree objects, so be sure to use
	196	* WRITE_TREE_MISSING_OK.
	197	*/
	198	if (cache_tree_update(istate, WRITE_TREE_MISSING_OK))
	199	return 0;
	200	}
6e773527 DS	201
	202	remove_fsmonitor(istate);
	203
	204	trace2_region_enter("index", "convert_to_sparse", istate->repo);
	205	istate->cache_nr = convert_to_sparse_rec(istate,
	206	0, 0, istate->cache_nr,
	207	"", 0, istate->cache_tree);
2de37c53 DS	208
	209	/* Clear and recompute the cache-tree */
	210	cache_tree_free(&istate->cache_tree);
	211	cache_tree_update(istate, 0);
	212
f8fe49e5 DS	213	istate->fsmonitor_has_run_once = 0;
	214	FREE_AND_NULL(istate->fsmonitor_dirty);
	215	FREE_AND_NULL(istate->fsmonitor_last_update);
	216
6e773527 DS	217	istate->sparse_index = 1;
	218	trace2_region_leave("index", "convert_to_sparse", istate->repo);
	219	return 0;
	220	}
4300f844 DS	221
	222	static void set_index_entry(struct index_state istate, int nr, struct cache_entry ce)
	223	{
	224	ALLOC_GROW(istate->cache, nr + 1, istate->cache_alloc);
	225
	226	istate->cache[nr] = ce;
	227	add_name_hash(istate, ce);
	228	}
	229
	230	static int add_path_to_index(const struct object_id *oid,
	231	struct strbuf base, const char path,
	232	unsigned int mode, void *context)
	233	{
	234	struct index_state istate = (struct index_state )context;
	235	struct cache_entry *ce;
	236	size_t len = base->len;
	237
	238	if (S_ISDIR(mode))
	239	return READ_TREE_RECURSIVE;
	240
	241	strbuf_addstr(base, path);
	242
	243	ce = make_cache_entry(istate, mode, oid, base->buf, 0, 0);
47410778	244	ce->ce_flags \|= CE_SKIP_WORKTREE \| CE_EXTENDED;
4300f844 DS	245	set_index_entry(istate, istate->cache_nr++, ce);
	246
	247	strbuf_setlen(base, len);
	248	return 0;
	249	}
3964fc2a DS	250
	251	void ensure_full_index(struct index_state *istate)
	252	{
4300f844 DS	253	int i;
	254	struct index_state *full;
	255	struct strbuf base = STRBUF_INIT;
	256
	257	if (!istate \|\| !istate->sparse_index)
	258	return;
	259
	260	if (!istate->repo)
	261	istate->repo = the_repository;
	262
	263	trace2_region_enter("index", "ensure_full_index", istate->repo);
	264
	265	/* initialize basics of new index */
	266	full = xcalloc(1, sizeof(struct index_state));
	267	memcpy(full, istate, sizeof(struct index_state));
	268
	269	/* then change the necessary things */
	270	full->sparse_index = 0;
	271	full->cache_alloc = (3 * istate->cache_alloc) / 2;
	272	full->cache_nr = 0;
	273	ALLOC_ARRAY(full->cache, full->cache_alloc);
	274
	275	for (i = 0; i < istate->cache_nr; i++) {
	276	struct cache_entry *ce = istate->cache[i];
	277	struct tree *tree;
	278	struct pathspec ps;
	279
	280	if (!S_ISSPARSEDIR(ce->ce_mode)) {
	281	set_index_entry(full, full->cache_nr++, ce);
	282	continue;
	283	}
	284	if (!(ce->ce_flags & CE_SKIP_WORKTREE))
	285	warning(_("index entry is a directory, but not sparse (%08x)"),
	286	ce->ce_flags);
	287
	288	/* recursively walk into cd->name */
	289	tree = lookup_tree(istate->repo, &ce->oid);
	290
	291	memset(&ps, 0, sizeof(ps));
	292	ps.recursive = 1;
	293	ps.has_wildcard = 1;
	294	ps.max_depth = -1;
	295
	296	strbuf_setlen(&base, 0);
	297	strbuf_add(&base, ce->name, strlen(ce->name));
	298
	299	read_tree_at(istate->repo, tree, &base, &ps,
	300	add_path_to_index, full);
	301
	302	/* free directory entries. full entries are re-used */
	303	discard_cache_entry(ce);
	304	}
	305
	306	/* Copy back into original index. */
	307	memcpy(&istate->name_hash, &full->name_hash, sizeof(full->name_hash));
d9e9b44d	308	memcpy(&istate->dir_hash, &full->dir_hash, sizeof(full->dir_hash));
4300f844 DS	309	istate->sparse_index = 0;
	310	free(istate->cache);
	311	istate->cache = full->cache;
	312	istate->cache_nr = full->cache_nr;
	313	istate->cache_alloc = full->cache_alloc;
f8fe49e5 DS	314	istate->fsmonitor_has_run_once = 0;
	315	FREE_AND_NULL(istate->fsmonitor_dirty);
	316	FREE_AND_NULL(istate->fsmonitor_last_update);
4300f844 DS	317
	318	strbuf_release(&base);
	319	free(full);
	320
2de37c53 DS	321	/* Clear and recompute the cache-tree */
	322	cache_tree_free(&istate->cache_tree);
	323	cache_tree_update(istate, 0);
	324
4300f844	325	trace2_region_leave("index", "ensure_full_index", istate->repo);
3964fc2a	326	}
71f82d03	327
b93fea08 VD	328	void ensure_correct_sparsity(struct index_state *istate)
	329	{
	330	/*
	331	* If the index can be sparse, make it sparse. Otherwise,
	332	* ensure the index is full.
	333	*/
	334	if (is_sparse_index_allowed(istate, 0))
	335	convert_to_sparse(istate, 0);
	336	else
	337	ensure_full_index(istate);
	338	}
	339
71f82d03 DS	340	/*
	341	* This static global helps avoid infinite recursion between
	342	* expand_to_path() and index_file_exists().
	343	*/
	344	static int in_expand_to_path = 0;
	345
	346	void expand_to_path(struct index_state *istate,
	347	const char *path, size_t pathlen, int icase)
	348	{
	349	struct strbuf path_mutable = STRBUF_INIT;
	350	size_t substr_len;
	351
	352	/* prevent extra recursion */
	353	if (in_expand_to_path)
	354	return;
	355
	356	if (!istate \|\| !istate->sparse_index)
	357	return;
	358
	359	if (!istate->repo)
	360	istate->repo = the_repository;
	361
	362	in_expand_to_path = 1;
	363
	364	/*
	365	* We only need to actually expand a region if the
	366	* following are both true:
	367	*
	368	* 1. 'path' is not already in the index.
	369	* 2. Some parent directory of 'path' is a sparse directory.
	370	*/
	371
	372	if (index_file_exists(istate, path, pathlen, icase))
	373	goto cleanup;
	374
	375	strbuf_add(&path_mutable, path, pathlen);
	376	strbuf_addch(&path_mutable, '/');
	377
	378	/* Check the name hash for all parent directories */
	379	substr_len = 0;
	380	while (substr_len < pathlen) {
	381	char temp;
	382	char *replace = strchr(path_mutable.buf + substr_len, '/');
	383
	384	if (!replace)
	385	break;
	386
	387	/* replace the character _after_ the slash */
	388	replace++;
	389	temp = *replace;
	390	*replace = '\0';
	391	if (index_file_exists(istate, path_mutable.buf,
	392	path_mutable.len, icase)) {
	393	/*
	394	* We found a parent directory in the name-hash
	395	* hashtable, because only sparse directory entries
	396	* have a trailing '/' character. Since "path" wasn't
	397	* in the index, perhaps it exists within this
	398	* sparse-directory. Expand accordingly.
	399	*/
	400	ensure_full_index(istate);
	401	break;
	402	}
	403
404	*replace = temp;
405	substr_len = replace - path_mutable.buf;
406	}
407
408	cleanup:
409	strbuf_release(&path_mutable);
410	in_expand_to_path = 0;
411	}