[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;
	char *config_path = repo_git_path(repo, "config.worktree");
	res = git_config_set_in_file_gently(config_path,
					    "index.sparse",
					    enable ? "true" : NULL);
	free(config_path);

	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)
			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	{
122ba1f7 DS	102	int res;
	103	char *config_path = repo_git_path(repo, "config.worktree");
	104	res = git_config_set_in_file_gently(config_path,
	105	"index.sparse",
	106	enable ? "true" : NULL);
	107	free(config_path);
58300f47	108
122ba1f7 DS	109	prepare_repo_settings(repo);
	110	repo->settings.sparse_index = enable;
	111	return res;
58300f47 DS	112	}
58300f47 DS	113
fc6609d1 DS	114	static int index_has_unmerged_entries(struct index_state *istate)
	115	{
	116	int i;
	117	for (i = 0; i < istate->cache_nr; i++) {
	118	if (ce_stage(istate->cache[i]))
	119	return 1;
	120	}
	121
	122	return 0;
	123	}
	124
b93fea08	125	static int is_sparse_index_allowed(struct index_state *istate, int flags)
6e773527	126	{
b93fea08	127	if (!core_apply_sparse_checkout \|\| !core_sparse_checkout_cone)
6e773527 DS	128	return 0;
6e773527 DS	129
58300f47 DS	130	if (!istate->repo)
	131	istate->repo = the_repository;
	132
ce7a9f01	133	if (!(flags & SPARSE_INDEX_MEMORY_ONLY)) {
b93fea08 VD	134	int test_env;
b93fea08 VD	135
ce7a9f01 DS	136	/*
	137	* The sparse index is not (yet) integrated with a split index.
	138	*/
	139	if (istate->split_index)
	140	return 0;
	141	/*
	142	* The GIT_TEST_SPARSE_INDEX environment variable triggers the
	143	* index.sparse config variable to be on.
	144	*/
	145	test_env = git_env_bool("GIT_TEST_SPARSE_INDEX", -1);
	146	if (test_env >= 0)
	147	set_sparse_index_config(istate->repo, test_env);
6e773527	148
ce7a9f01 DS	149	/*
	150	* Only convert to sparse if index.sparse is set.
	151	*/
	152	prepare_repo_settings(istate->repo);
	153	if (!istate->repo->settings.sparse_index)
6e773527 DS	154	return 0;
	155	}
	156
02155c8c DS	157	if (init_sparse_checkout_patterns(istate))
02155c8c DS	158	return 0;
6e773527	159
e27eab45 DS	160	/*
	161	* We need cone-mode patterns to use sparse-index. If a user edits
	162	* their sparse-checkout file manually, then we can detect during
	163	* parsing that they are not actually using cone-mode patterns and
	164	* hence we need to abort this conversion _without error_. Warnings
	165	* already exist in the pattern parsing to inform the user of their
	166	* bad patterns.
	167	*/
	168	if (!istate->sparse_checkout_patterns->use_cone_patterns)
	169	return 0;
6e773527	170
b93fea08 VD	171	return 1;
	172	}
	173
	174	int convert_to_sparse(struct index_state *istate, int flags)
	175	{
	176	/*
	177	* If the index is already sparse, empty, or otherwise
	178	* cannot be converted to sparse, do not convert.
	179	*/
	180	if (istate->sparse_index \|\| !istate->cache_nr \|\|
	181	!is_sparse_index_allowed(istate, flags))
	182	return 0;
	183
fc6609d1 DS	184	/*
	185	* NEEDSWORK: If we have unmerged entries, then stay full.
	186	* Unmerged entries prevent the cache-tree extension from working.
	187	*/
	188	if (index_has_unmerged_entries(istate))
	189	return 0;
	190
13f69f30 VD	191	if (!cache_tree_fully_valid(istate->cache_tree)) {
	192	/* Clear and recompute the cache-tree */
	193	cache_tree_free(&istate->cache_tree);
	194
	195	/*
	196	* Silently return if there is a problem with the cache tree update,
	197	* which might just be due to a conflict state in some entry.
	198	*
	199	* This might create new tree objects, so be sure to use
	200	* WRITE_TREE_MISSING_OK.
	201	*/
	202	if (cache_tree_update(istate, WRITE_TREE_MISSING_OK))
	203	return 0;
	204	}
6e773527 DS	205
	206	remove_fsmonitor(istate);
	207
	208	trace2_region_enter("index", "convert_to_sparse", istate->repo);
	209	istate->cache_nr = convert_to_sparse_rec(istate,
	210	0, 0, istate->cache_nr,
	211	"", 0, istate->cache_tree);
2de37c53 DS	212
	213	/* Clear and recompute the cache-tree */
	214	cache_tree_free(&istate->cache_tree);
	215	cache_tree_update(istate, 0);
	216
f8fe49e5 DS	217	istate->fsmonitor_has_run_once = 0;
	218	FREE_AND_NULL(istate->fsmonitor_dirty);
	219	FREE_AND_NULL(istate->fsmonitor_last_update);
	220
6e773527 DS	221	istate->sparse_index = 1;
	222	trace2_region_leave("index", "convert_to_sparse", istate->repo);
	223	return 0;
	224	}
4300f844 DS	225
	226	static void set_index_entry(struct index_state istate, int nr, struct cache_entry ce)
	227	{
	228	ALLOC_GROW(istate->cache, nr + 1, istate->cache_alloc);
	229
	230	istate->cache[nr] = ce;
	231	add_name_hash(istate, ce);
	232	}
	233
	234	static int add_path_to_index(const struct object_id *oid,
	235	struct strbuf base, const char path,
	236	unsigned int mode, void *context)
	237	{
	238	struct index_state istate = (struct index_state )context;
	239	struct cache_entry *ce;
	240	size_t len = base->len;
	241
	242	if (S_ISDIR(mode))
	243	return READ_TREE_RECURSIVE;
	244
	245	strbuf_addstr(base, path);
	246
	247	ce = make_cache_entry(istate, mode, oid, base->buf, 0, 0);
47410778	248	ce->ce_flags \|= CE_SKIP_WORKTREE \| CE_EXTENDED;
4300f844 DS	249	set_index_entry(istate, istate->cache_nr++, ce);
	250
	251	strbuf_setlen(base, len);
	252	return 0;
	253	}
3964fc2a DS	254
	255	void ensure_full_index(struct index_state *istate)
	256	{
4300f844 DS	257	int i;
	258	struct index_state *full;
	259	struct strbuf base = STRBUF_INIT;
	260
	261	if (!istate \|\| !istate->sparse_index)
	262	return;
	263
	264	if (!istate->repo)
	265	istate->repo = the_repository;
	266
	267	trace2_region_enter("index", "ensure_full_index", istate->repo);
	268
	269	/* initialize basics of new index */
	270	full = xcalloc(1, sizeof(struct index_state));
	271	memcpy(full, istate, sizeof(struct index_state));
	272
	273	/* then change the necessary things */
	274	full->sparse_index = 0;
	275	full->cache_alloc = (3 * istate->cache_alloc) / 2;
	276	full->cache_nr = 0;
	277	ALLOC_ARRAY(full->cache, full->cache_alloc);
	278
	279	for (i = 0; i < istate->cache_nr; i++) {
	280	struct cache_entry *ce = istate->cache[i];
	281	struct tree *tree;
	282	struct pathspec ps;
	283
	284	if (!S_ISSPARSEDIR(ce->ce_mode)) {
	285	set_index_entry(full, full->cache_nr++, ce);
	286	continue;
	287	}
	288	if (!(ce->ce_flags & CE_SKIP_WORKTREE))
	289	warning(_("index entry is a directory, but not sparse (%08x)"),
	290	ce->ce_flags);
	291
	292	/* recursively walk into cd->name */
	293	tree = lookup_tree(istate->repo, &ce->oid);
	294
	295	memset(&ps, 0, sizeof(ps));
	296	ps.recursive = 1;
	297	ps.has_wildcard = 1;
	298	ps.max_depth = -1;
	299
	300	strbuf_setlen(&base, 0);
	301	strbuf_add(&base, ce->name, strlen(ce->name));
	302
	303	read_tree_at(istate->repo, tree, &base, &ps,
	304	add_path_to_index, full);
	305
	306	/* free directory entries. full entries are re-used */
	307	discard_cache_entry(ce);
	308	}
	309
	310	/* Copy back into original index. */
	311	memcpy(&istate->name_hash, &full->name_hash, sizeof(full->name_hash));
d9e9b44d	312	memcpy(&istate->dir_hash, &full->dir_hash, sizeof(full->dir_hash));
4300f844 DS	313	istate->sparse_index = 0;
	314	free(istate->cache);
	315	istate->cache = full->cache;
	316	istate->cache_nr = full->cache_nr;
	317	istate->cache_alloc = full->cache_alloc;
f8fe49e5 DS	318	istate->fsmonitor_has_run_once = 0;
	319	FREE_AND_NULL(istate->fsmonitor_dirty);
	320	FREE_AND_NULL(istate->fsmonitor_last_update);
4300f844 DS	321
	322	strbuf_release(&base);
	323	free(full);
	324
2de37c53 DS	325	/* Clear and recompute the cache-tree */
	326	cache_tree_free(&istate->cache_tree);
	327	cache_tree_update(istate, 0);
	328
4300f844	329	trace2_region_leave("index", "ensure_full_index", istate->repo);
3964fc2a	330	}
71f82d03	331
b93fea08 VD	332	void ensure_correct_sparsity(struct index_state *istate)
	333	{
	334	/*
	335	* If the index can be sparse, make it sparse. Otherwise,
	336	* ensure the index is full.
	337	*/
	338	if (is_sparse_index_allowed(istate, 0))
	339	convert_to_sparse(istate, 0);
	340	else
	341	ensure_full_index(istate);
	342	}
	343
71f82d03 DS	344	/*
	345	* This static global helps avoid infinite recursion between
	346	* expand_to_path() and index_file_exists().
	347	*/
	348	static int in_expand_to_path = 0;
	349
	350	void expand_to_path(struct index_state *istate,
	351	const char *path, size_t pathlen, int icase)
	352	{
	353	struct strbuf path_mutable = STRBUF_INIT;
	354	size_t substr_len;
	355
	356	/* prevent extra recursion */
	357	if (in_expand_to_path)
	358	return;
	359
	360	if (!istate \|\| !istate->sparse_index)
	361	return;
	362
	363	if (!istate->repo)
	364	istate->repo = the_repository;
	365
	366	in_expand_to_path = 1;
	367
	368	/*
	369	* We only need to actually expand a region if the
	370	* following are both true:
	371	*
	372	* 1. 'path' is not already in the index.
	373	* 2. Some parent directory of 'path' is a sparse directory.
	374	*/
	375
	376	if (index_file_exists(istate, path, pathlen, icase))
	377	goto cleanup;
	378
	379	strbuf_add(&path_mutable, path, pathlen);
	380	strbuf_addch(&path_mutable, '/');
	381
	382	/* Check the name hash for all parent directories */
	383	substr_len = 0;
	384	while (substr_len < pathlen) {
	385	char temp;
	386	char *replace = strchr(path_mutable.buf + substr_len, '/');
	387
	388	if (!replace)
	389	break;
	390
	391	/* replace the character _after_ the slash */
	392	replace++;
	393	temp = *replace;
	394	*replace = '\0';
	395	if (index_file_exists(istate, path_mutable.buf,
	396	path_mutable.len, icase)) {
	397	/*
	398	* We found a parent directory in the name-hash
	399	* hashtable, because only sparse directory entries
	400	* have a trailing '/' character. Since "path" wasn't
	401	* in the index, perhaps it exists within this
	402	* sparse-directory. Expand accordingly.
	403	*/
	404	ensure_full_index(istate);
	405	break;
	406	}
	407
408	*replace = temp;
409	substr_len = replace - path_mutable.buf;
410	}
411
412	cleanup:
413	strbuf_release(&path_mutable);
414	in_expand_to_path = 0;
415	}