[thirdparty/git.git] / fsmonitor.c

#include "cache.h"
#include "config.h"
#include "dir.h"
#include "ewah/ewok.h"
#include "fsmonitor.h"
#include "run-command.h"
#include "strbuf.h"

#define INDEX_EXTENSION_VERSION1	(1)
#define INDEX_EXTENSION_VERSION2	(2)
#define HOOK_INTERFACE_VERSION1		(1)
#define HOOK_INTERFACE_VERSION2		(2)

struct trace_key trace_fsmonitor = TRACE_KEY_INIT(FSMONITOR);

static void assert_index_minimum(struct index_state *istate, size_t pos)
{
	if (pos > istate->cache_nr)
		BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
		    (uintmax_t)pos, istate->cache_nr);
}

static void fsmonitor_ewah_callback(size_t pos, void *is)
{
	struct index_state *istate = (struct index_state *)is;
	struct cache_entry *ce;

	assert_index_minimum(istate, pos + 1);

	ce = istate->cache[pos];
	ce->ce_flags &= ~CE_FSMONITOR_VALID;
}

static int fsmonitor_hook_version(void)
{
	int hook_version;

	if (git_config_get_int("core.fsmonitorhookversion", &hook_version))
		return -1;

	if (hook_version == HOOK_INTERFACE_VERSION1 ||
	    hook_version == HOOK_INTERFACE_VERSION2)
		return hook_version;

	warning("Invalid hook version '%i' in core.fsmonitorhookversion. "
		"Must be 1 or 2.", hook_version);
	return -1;
}

int read_fsmonitor_extension(struct index_state *istate, const void *data,
	unsigned long sz)
{
	const char *index = data;
	uint32_t hdr_version;
	uint32_t ewah_size;
	struct ewah_bitmap *fsmonitor_dirty;
	int ret;
	uint64_t timestamp;
	struct strbuf last_update = STRBUF_INIT;

	if (sz < sizeof(uint32_t) + 1 + sizeof(uint32_t))
		return error("corrupt fsmonitor extension (too short)");

	hdr_version = get_be32(index);
	index += sizeof(uint32_t);
	if (hdr_version == INDEX_EXTENSION_VERSION1) {
		timestamp = get_be64(index);
		strbuf_addf(&last_update, "%"PRIu64"", timestamp);
		index += sizeof(uint64_t);
	} else if (hdr_version == INDEX_EXTENSION_VERSION2) {
		strbuf_addstr(&last_update, index);
		index += last_update.len + 1;
	} else {
		return error("bad fsmonitor version %d", hdr_version);
	}

	istate->fsmonitor_last_update = strbuf_detach(&last_update, NULL);

	ewah_size = get_be32(index);
	index += sizeof(uint32_t);

	fsmonitor_dirty = ewah_new();
	ret = ewah_read_mmap(fsmonitor_dirty, index, ewah_size);
	if (ret != ewah_size) {
		ewah_free(fsmonitor_dirty);
		return error("failed to parse ewah bitmap reading fsmonitor index extension");
	}
	istate->fsmonitor_dirty = fsmonitor_dirty;

	if (!istate->split_index)
		assert_index_minimum(istate, istate->fsmonitor_dirty->bit_size);

	trace2_data_string("index", NULL, "extension/fsmn/read/token",
			   istate->fsmonitor_last_update);
	trace_printf_key(&trace_fsmonitor,
			 "read fsmonitor extension successful '%s'",
			 istate->fsmonitor_last_update);
	return 0;
}

void fill_fsmonitor_bitmap(struct index_state *istate)
{
	unsigned int i, skipped = 0;
	istate->fsmonitor_dirty = ewah_new();
	for (i = 0; i < istate->cache_nr; i++) {
		if (istate->cache[i]->ce_flags & CE_REMOVE)
			skipped++;
		else if (!(istate->cache[i]->ce_flags & CE_FSMONITOR_VALID))
			ewah_set(istate->fsmonitor_dirty, i - skipped);
	}
}

void write_fsmonitor_extension(struct strbuf *sb, struct index_state *istate)
{
	uint32_t hdr_version;
	uint32_t ewah_start;
	uint32_t ewah_size = 0;
	int fixup = 0;

	if (!istate->split_index)
		assert_index_minimum(istate, istate->fsmonitor_dirty->bit_size);

	put_be32(&hdr_version, INDEX_EXTENSION_VERSION2);
	strbuf_add(sb, &hdr_version, sizeof(uint32_t));

	strbuf_addstr(sb, istate->fsmonitor_last_update);
	strbuf_addch(sb, 0); /* Want to keep a NUL */

	fixup = sb->len;
	strbuf_add(sb, &ewah_size, sizeof(uint32_t)); /* we'll fix this up later */

	ewah_start = sb->len;
	ewah_serialize_strbuf(istate->fsmonitor_dirty, sb);
	ewah_free(istate->fsmonitor_dirty);
	istate->fsmonitor_dirty = NULL;

	/* fix up size field */
	put_be32(&ewah_size, sb->len - ewah_start);
	memcpy(sb->buf + fixup, &ewah_size, sizeof(uint32_t));

	trace2_data_string("index", NULL, "extension/fsmn/write/token",
			   istate->fsmonitor_last_update);
	trace_printf_key(&trace_fsmonitor,
			 "write fsmonitor extension successful '%s'",
			 istate->fsmonitor_last_update);
}

/*
 * Call the query-fsmonitor hook passing the last update token of the saved results.
 */
static int query_fsmonitor(int version, const char *last_update, struct strbuf *query_result)
{
	struct child_process cp = CHILD_PROCESS_INIT;
	int result;

	if (!core_fsmonitor)
		return -1;

	strvec_push(&cp.args, core_fsmonitor);
	strvec_pushf(&cp.args, "%d", version);
	strvec_pushf(&cp.args, "%s", last_update);
	cp.use_shell = 1;
	cp.dir = get_git_work_tree();

	trace2_region_enter("fsm_hook", "query", NULL);

	result = capture_command(&cp, query_result, 1024);

	if (result)
		trace2_data_intmax("fsm_hook", NULL, "query/failed", result);
	else {
		trace2_data_intmax("fsm_hook", NULL, "query/response-length",
				   query_result->len);

		if (fsmonitor_is_trivial_response(query_result))
			trace2_data_intmax("fsm_hook", NULL,
					   "query/trivial-response", 1);
	}

	trace2_region_leave("fsm_hook", "query", NULL);

	return result;
}

int fsmonitor_is_trivial_response(const struct strbuf *query_result)
{
	static char trivial_response[3] = { '\0', '/', '\0' };

	return query_result->len >= 3 &&
		!memcmp(trivial_response,
			&query_result->buf[query_result->len - 3], 3);
}

static void fsmonitor_refresh_callback(struct index_state *istate, char *name)
{
	int i, len = strlen(name);
	if (name[len - 1] == '/') {

		/*
		 * TODO We should binary search to find the first path with
		 * TODO this directory prefix.  Then linearly update entries
		 * TODO while the prefix matches.  Taking care to search without
		 * TODO the trailing slash -- because '/' sorts after a few
		 * TODO interesting special chars, like '.' and ' '.
		 */

		/* Mark all entries for the folder invalid */
		for (i = 0; i < istate->cache_nr; i++) {
			if (istate->cache[i]->ce_flags & CE_FSMONITOR_VALID &&
			    starts_with(istate->cache[i]->name, name))
				istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;
		}
		/* Need to remove the / from the path for the untracked cache */
		name[len - 1] = '\0';
	} else {
		int pos = index_name_pos(istate, name, strlen(name));

		if (pos >= 0) {
			struct cache_entry *ce = istate->cache[pos];
			ce->ce_flags &= ~CE_FSMONITOR_VALID;
		}
	}

	/*
	 * Mark the untracked cache dirty even if it wasn't found in the index
	 * as it could be a new untracked file.
	 */
	trace_printf_key(&trace_fsmonitor, "fsmonitor_refresh_callback '%s'", name);
	untracked_cache_invalidate_path(istate, name, 0);
}

void refresh_fsmonitor(struct index_state *istate)
{
	struct strbuf query_result = STRBUF_INIT;
	int query_success = 0, hook_version = -1;
	size_t bol = 0; /* beginning of line */
	uint64_t last_update;
	struct strbuf last_update_token = STRBUF_INIT;
	char *buf;
	unsigned int i;

	if (!core_fsmonitor || istate->fsmonitor_has_run_once)
		return;

	hook_version = fsmonitor_hook_version();

	istate->fsmonitor_has_run_once = 1;

	trace_printf_key(&trace_fsmonitor, "refresh fsmonitor");
	/*
	 * This could be racy so save the date/time now and query_fsmonitor
	 * should be inclusive to ensure we don't miss potential changes.
	 */
	last_update = getnanotime();
	if (hook_version == HOOK_INTERFACE_VERSION1)
		strbuf_addf(&last_update_token, "%"PRIu64"", last_update);

	/*
	 * If we have a last update token, call query_fsmonitor for the set of
	 * changes since that token, else assume everything is possibly dirty
	 * and check it all.
	 */
	if (istate->fsmonitor_last_update) {
		if (hook_version == -1 || hook_version == HOOK_INTERFACE_VERSION2) {
			query_success = !query_fsmonitor(HOOK_INTERFACE_VERSION2,
				istate->fsmonitor_last_update, &query_result);

			if (query_success) {
				if (hook_version < 0)
					hook_version = HOOK_INTERFACE_VERSION2;

				/*
				 * First entry will be the last update token
				 * Need to use a char * variable because static
				 * analysis was suggesting to use strbuf_addbuf
				 * but we don't want to copy the entire strbuf
				 * only the chars up to the first NUL
				 */
				buf = query_result.buf;
				strbuf_addstr(&last_update_token, buf);
				if (!last_update_token.len) {
					warning("Empty last update token.");
					query_success = 0;
				} else {
					bol = last_update_token.len + 1;
				}
			} else if (hook_version < 0) {
				hook_version = HOOK_INTERFACE_VERSION1;
				if (!last_update_token.len)
					strbuf_addf(&last_update_token, "%"PRIu64"", last_update);
			}
		}

		if (hook_version == HOOK_INTERFACE_VERSION1) {
			query_success = !query_fsmonitor(HOOK_INTERFACE_VERSION1,
				istate->fsmonitor_last_update, &query_result);
		}

		trace_performance_since(last_update, "fsmonitor process '%s'", core_fsmonitor);
		trace_printf_key(&trace_fsmonitor, "fsmonitor process '%s' returned %s",
			core_fsmonitor, query_success ? "success" : "failure");
	}

	/* a fsmonitor process can return '/' to indicate all entries are invalid */
	if (query_success && query_result.buf[bol] != '/') {
		/* Mark all entries returned by the monitor as dirty */
		buf = query_result.buf;
		for (i = bol; i < query_result.len; i++) {
			if (buf[i] != '\0')
				continue;
			fsmonitor_refresh_callback(istate, buf + bol);
			bol = i + 1;
		}
		if (bol < query_result.len)
			fsmonitor_refresh_callback(istate, buf + bol);

		/* Now mark the untracked cache for fsmonitor usage */
		if (istate->untracked)
			istate->untracked->use_fsmonitor = 1;
	} else {

		/* We only want to run the post index changed hook if we've actually changed entries, so keep track
		 * if we actually changed entries or not */
		int is_cache_changed = 0;
		/* Mark all entries invalid */
		for (i = 0; i < istate->cache_nr; i++) {
			if (istate->cache[i]->ce_flags & CE_FSMONITOR_VALID) {
				is_cache_changed = 1;
				istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;
			}
		}

		/* If we're going to check every file, ensure we save the results */
		if (is_cache_changed)
			istate->cache_changed |= FSMONITOR_CHANGED;

		if (istate->untracked)
			istate->untracked->use_fsmonitor = 0;
	}
	strbuf_release(&query_result);

	/* Now that we've updated istate, save the last_update_token */
	FREE_AND_NULL(istate->fsmonitor_last_update);
	istate->fsmonitor_last_update = strbuf_detach(&last_update_token, NULL);
}

/*
 * The caller wants to turn on FSMonitor.  And when the caller writes
 * the index to disk, a FSMonitor extension should be included.  This
 * requires that `istate->fsmonitor_last_update` not be NULL.  But we
 * have not actually talked to a FSMonitor process yet, so we don't
 * have an initial value for this field.
 *
 * For a protocol V1 FSMonitor process, this field is a formatted
 * "nanoseconds since epoch" field.  However, for a protocol V2
 * FSMonitor process, this field is an opaque token.
 *
 * Historically, `add_fsmonitor()` has initialized this field to the
 * current time for protocol V1 processes.  There are lots of race
 * conditions here, but that code has shipped...
 *
 * The only true solution is to use a V2 FSMonitor and get a current
 * or default token value (that it understands), but we cannot do that
 * until we have actually talked to an instance of the FSMonitor process
 * (but the protocol requires that we send a token first...).
 *
 * For simplicity, just initialize like we have a V1 process and require
 * that V2 processes adapt.
 */
static void initialize_fsmonitor_last_update(struct index_state *istate)
{
	struct strbuf last_update = STRBUF_INIT;

	strbuf_addf(&last_update, "%"PRIu64"", getnanotime());
	istate->fsmonitor_last_update = strbuf_detach(&last_update, NULL);
}

void add_fsmonitor(struct index_state *istate)
{
	unsigned int i;

	if (!istate->fsmonitor_last_update) {
		trace_printf_key(&trace_fsmonitor, "add fsmonitor");
		istate->cache_changed |= FSMONITOR_CHANGED;
		initialize_fsmonitor_last_update(istate);

		/* reset the fsmonitor state */
		for (i = 0; i < istate->cache_nr; i++)
			istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;

		/* reset the untracked cache */
		if (istate->untracked) {
			add_untracked_cache(istate);
			istate->untracked->use_fsmonitor = 1;
		}

		/* Update the fsmonitor state */
		refresh_fsmonitor(istate);
	}
}

void remove_fsmonitor(struct index_state *istate)
{
	if (istate->fsmonitor_last_update) {
		trace_printf_key(&trace_fsmonitor, "remove fsmonitor");
		istate->cache_changed |= FSMONITOR_CHANGED;
		FREE_AND_NULL(istate->fsmonitor_last_update);
	}
}

void tweak_fsmonitor(struct index_state *istate)
{
	unsigned int i;
	int fsmonitor_enabled = git_config_get_fsmonitor();

	if (istate->fsmonitor_dirty) {
		if (fsmonitor_enabled) {
			/* Mark all entries valid */
			for (i = 0; i < istate->cache_nr; i++) {
				istate->cache[i]->ce_flags |= CE_FSMONITOR_VALID;
			}

			/* Mark all previously saved entries as dirty */
			assert_index_minimum(istate, istate->fsmonitor_dirty->bit_size);
			ewah_each_bit(istate->fsmonitor_dirty, fsmonitor_ewah_callback, istate);

			refresh_fsmonitor(istate);
		}

		ewah_free(istate->fsmonitor_dirty);
		istate->fsmonitor_dirty = NULL;
	}

	switch (fsmonitor_enabled) {
	case -1: /* keep: do nothing */
		break;
	case 0: /* false */
		remove_fsmonitor(istate);
		break;
	case 1: /* true */
		add_fsmonitor(istate);
		break;
	default: /* unknown value: do nothing */
		break;
	}
}
Commit	Line	Data
883e248b BP	1	#include "cache.h"
	2	#include "config.h"
	3	#include "dir.h"
	4	#include "ewah/ewok.h"
	5	#include "fsmonitor.h"
	6	#include "run-command.h"
	7	#include "strbuf.h"
	8
56c69100 KW	9	#define INDEX_EXTENSION_VERSION1 (1)
56c69100 KW	10	#define INDEX_EXTENSION_VERSION2 (2)
8da2c576 KW	11	#define HOOK_INTERFACE_VERSION1 (1)
8da2c576 KW	12	#define HOOK_INTERFACE_VERSION2 (2)
883e248b BP	13
	14	struct trace_key trace_fsmonitor = TRACE_KEY_INIT(FSMONITOR);
	15
cae70acf DS	16	static void assert_index_minimum(struct index_state *istate, size_t pos)
	17	{
	18	if (pos > istate->cache_nr)
	19	BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
	20	(uintmax_t)pos, istate->cache_nr);
	21	}
	22
883e248b BP	23	static void fsmonitor_ewah_callback(size_t pos, void *is)
	24	{
	25	struct index_state istate = (struct index_state )is;
3444ec2e	26	struct cache_entry *ce;
883e248b	27
cae70acf	28	assert_index_minimum(istate, pos + 1);
3444ec2e WB	29
3444ec2e WB	30	ce = istate->cache[pos];
883e248b BP	31	ce->ce_flags &= ~CE_FSMONITOR_VALID;
	32	}
	33
8da2c576 KW	34	static int fsmonitor_hook_version(void)
	35	{
	36	int hook_version;
	37
	38	if (git_config_get_int("core.fsmonitorhookversion", &hook_version))
	39	return -1;
	40
	41	if (hook_version == HOOK_INTERFACE_VERSION1 \|\|
	42	hook_version == HOOK_INTERFACE_VERSION2)
	43	return hook_version;
	44
	45	warning("Invalid hook version '%i' in core.fsmonitorhookversion. "
	46	"Must be 1 or 2.", hook_version);
	47	return -1;
	48	}
	49
883e248b BP	50	int read_fsmonitor_extension(struct index_state istate, const void data,
	51	unsigned long sz)
	52	{
	53	const char *index = data;
	54	uint32_t hdr_version;
	55	uint32_t ewah_size;
	56	struct ewah_bitmap *fsmonitor_dirty;
883e248b	57	int ret;
56c69100 KW	58	uint64_t timestamp;
56c69100 KW	59	struct strbuf last_update = STRBUF_INIT;
883e248b	60
56c69100	61	if (sz < sizeof(uint32_t) + 1 + sizeof(uint32_t))
883e248b BP	62	return error("corrupt fsmonitor extension (too short)");
	63
	64	hdr_version = get_be32(index);
	65	index += sizeof(uint32_t);
56c69100 KW	66	if (hdr_version == INDEX_EXTENSION_VERSION1) {
	67	timestamp = get_be64(index);
	68	strbuf_addf(&last_update, "%"PRIu64"", timestamp);
	69	index += sizeof(uint64_t);
	70	} else if (hdr_version == INDEX_EXTENSION_VERSION2) {
	71	strbuf_addstr(&last_update, index);
	72	index += last_update.len + 1;
	73	} else {
883e248b	74	return error("bad fsmonitor version %d", hdr_version);
56c69100	75	}
883e248b	76
56c69100	77	istate->fsmonitor_last_update = strbuf_detach(&last_update, NULL);
883e248b BP	78
	79	ewah_size = get_be32(index);
	80	index += sizeof(uint32_t);
	81
	82	fsmonitor_dirty = ewah_new();
	83	ret = ewah_read_mmap(fsmonitor_dirty, index, ewah_size);
	84	if (ret != ewah_size) {
	85	ewah_free(fsmonitor_dirty);
	86	return error("failed to parse ewah bitmap reading fsmonitor index extension");
	87	}
ba1b9cac	88	istate->fsmonitor_dirty = fsmonitor_dirty;
883e248b	89
cae70acf DS	90	if (!istate->split_index)
cae70acf DS	91	assert_index_minimum(istate, istate->fsmonitor_dirty->bit_size);
3444ec2e	92
29fbbf43 JH	93	trace2_data_string("index", NULL, "extension/fsmn/read/token",
	94	istate->fsmonitor_last_update);
	95	trace_printf_key(&trace_fsmonitor,
	96	"read fsmonitor extension successful '%s'",
	97	istate->fsmonitor_last_update);
883e248b BP	98	return 0;
	99	}
	100
3bd28eb2 AV	101	void fill_fsmonitor_bitmap(struct index_state *istate)
3bd28eb2 AV	102	{
3444ec2e	103	unsigned int i, skipped = 0;
3bd28eb2	104	istate->fsmonitor_dirty = ewah_new();
3444ec2e WB	105	for (i = 0; i < istate->cache_nr; i++) {
	106	if (istate->cache[i]->ce_flags & CE_REMOVE)
	107	skipped++;
	108	else if (!(istate->cache[i]->ce_flags & CE_FSMONITOR_VALID))
	109	ewah_set(istate->fsmonitor_dirty, i - skipped);
	110	}
3bd28eb2 AV	111	}
3bd28eb2 AV	112
883e248b BP	113	void write_fsmonitor_extension(struct strbuf sb, struct index_state istate)
	114	{
	115	uint32_t hdr_version;
883e248b BP	116	uint32_t ewah_start;
	117	uint32_t ewah_size = 0;
	118	int fixup = 0;
	119
cae70acf DS	120	if (!istate->split_index)
cae70acf DS	121	assert_index_minimum(istate, istate->fsmonitor_dirty->bit_size);
3444ec2e	122
56c69100	123	put_be32(&hdr_version, INDEX_EXTENSION_VERSION2);
883e248b BP	124	strbuf_add(sb, &hdr_version, sizeof(uint32_t));
883e248b BP	125
56c69100 KW	126	strbuf_addstr(sb, istate->fsmonitor_last_update);
	127	strbuf_addch(sb, 0); /* Want to keep a NUL */
	128
883e248b BP	129	fixup = sb->len;
	130	strbuf_add(sb, &ewah_size, sizeof(uint32_t)); /* we'll fix this up later */
	131
	132	ewah_start = sb->len;
3bd28eb2 AV	133	ewah_serialize_strbuf(istate->fsmonitor_dirty, sb);
	134	ewah_free(istate->fsmonitor_dirty);
	135	istate->fsmonitor_dirty = NULL;
883e248b BP	136
	137	/* fix up size field */
	138	put_be32(&ewah_size, sb->len - ewah_start);
	139	memcpy(sb->buf + fixup, &ewah_size, sizeof(uint32_t));
	140
29fbbf43 JH	141	trace2_data_string("index", NULL, "extension/fsmn/write/token",
	142	istate->fsmonitor_last_update);
	143	trace_printf_key(&trace_fsmonitor,
	144	"write fsmonitor extension successful '%s'",
	145	istate->fsmonitor_last_update);
883e248b BP	146	}
	147
	148	/*
56c69100	149	* Call the query-fsmonitor hook passing the last update token of the saved results.
883e248b	150	*/
56c69100	151	static int query_fsmonitor(int version, const char last_update, struct strbuf query_result)
883e248b BP	152	{
883e248b BP	153	struct child_process cp = CHILD_PROCESS_INIT;
940b94f3	154	int result;
883e248b	155
735e4173	156	if (!core_fsmonitor)
883e248b BP	157	return -1;
883e248b BP	158
ef8d7ac4 JK	159	strvec_push(&cp.args, core_fsmonitor);
	160	strvec_pushf(&cp.args, "%d", version);
	161	strvec_pushf(&cp.args, "%s", last_update);
883e248b	162	cp.use_shell = 1;
11cf33be	163	cp.dir = get_git_work_tree();
883e248b	164
940b94f3 JH	165	trace2_region_enter("fsm_hook", "query", NULL);
	166
	167	result = capture_command(&cp, query_result, 1024);
	168
	169	if (result)
	170	trace2_data_intmax("fsm_hook", NULL, "query/failed", result);
	171	else {
	172	trace2_data_intmax("fsm_hook", NULL, "query/response-length",
	173	query_result->len);
	174
	175	if (fsmonitor_is_trivial_response(query_result))
	176	trace2_data_intmax("fsm_hook", NULL,
	177	"query/trivial-response", 1);
	178	}
	179
	180	trace2_region_leave("fsm_hook", "query", NULL);
	181
	182	return result;
883e248b BP	183	}
883e248b BP	184
940b94f3	185	int fsmonitor_is_trivial_response(const struct strbuf *query_result)
883e248b	186	{
940b94f3	187	static char trivial_response[3] = { '\0', '/', '\0' };
940b94f3	188
097ea2c8 AH	189	return query_result->len >= 3 &&
	190	!memcmp(trivial_response,
	191	&query_result->buf[query_result->len - 3], 3);
883e248b BP	192	}
883e248b BP	193
ff03836b	194	static void fsmonitor_refresh_callback(struct index_state istate, char name)
883e248b	195	{
ff03836b KW	196	int i, len = strlen(name);
	197	if (name[len - 1] == '/') {
	198
	199	/*
	200	* TODO We should binary search to find the first path with
	201	* TODO this directory prefix. Then linearly update entries
	202	* TODO while the prefix matches. Taking care to search without
	203	* TODO the trailing slash -- because '/' sorts after a few
	204	* TODO interesting special chars, like '.' and ' '.
	205	*/
	206
	207	/* Mark all entries for the folder invalid */
	208	for (i = 0; i < istate->cache_nr; i++) {
	209	if (istate->cache[i]->ce_flags & CE_FSMONITOR_VALID &&
	210	starts_with(istate->cache[i]->name, name))
	211	istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;
	212	}
	213	/* Need to remove the / from the path for the untracked cache */
	214	name[len - 1] = '\0';
	215	} else {
	216	int pos = index_name_pos(istate, name, strlen(name));
883e248b	217
ff03836b KW	218	if (pos >= 0) {
	219	struct cache_entry *ce = istate->cache[pos];
	220	ce->ce_flags &= ~CE_FSMONITOR_VALID;
	221	}
883e248b BP	222	}
	223
	224	/*
	225	* Mark the untracked cache dirty even if it wasn't found in the index
	226	* as it could be a new untracked file.
	227	*/
	228	trace_printf_key(&trace_fsmonitor, "fsmonitor_refresh_callback '%s'", name);
0cacebf0	229	untracked_cache_invalidate_path(istate, name, 0);
883e248b BP	230	}
	231
	232	void refresh_fsmonitor(struct index_state *istate)
	233	{
883e248b	234	struct strbuf query_result = STRBUF_INIT;
8da2c576 KW	235	int query_success = 0, hook_version = -1;
8da2c576 KW	236	size_t bol = 0; /* beginning of line */
883e248b	237	uint64_t last_update;
56c69100	238	struct strbuf last_update_token = STRBUF_INIT;
883e248b	239	char *buf;
5d137fc2	240	unsigned int i;
883e248b	241
398a3b08	242	if (!core_fsmonitor \|\| istate->fsmonitor_has_run_once)
883e248b	243	return;
8da2c576 KW	244
	245	hook_version = fsmonitor_hook_version();
	246
398a3b08	247	istate->fsmonitor_has_run_once = 1;
883e248b BP	248
	249	trace_printf_key(&trace_fsmonitor, "refresh fsmonitor");
	250	/*
	251	* This could be racy so save the date/time now and query_fsmonitor
	252	* should be inclusive to ensure we don't miss potential changes.
	253	*/
	254	last_update = getnanotime();
8da2c576 KW	255	if (hook_version == HOOK_INTERFACE_VERSION1)
8da2c576 KW	256	strbuf_addf(&last_update_token, "%"PRIu64"", last_update);
883e248b BP	257
883e248b BP	258	/*
8da2c576 KW	259	* If we have a last update token, call query_fsmonitor for the set of
8da2c576 KW	260	* changes since that token, else assume everything is possibly dirty
883e248b BP	261	* and check it all.
	262	*/
	263	if (istate->fsmonitor_last_update) {
8da2c576 KW	264	if (hook_version == -1 \|\| hook_version == HOOK_INTERFACE_VERSION2) {
	265	query_success = !query_fsmonitor(HOOK_INTERFACE_VERSION2,
	266	istate->fsmonitor_last_update, &query_result);
	267
	268	if (query_success) {
	269	if (hook_version < 0)
	270	hook_version = HOOK_INTERFACE_VERSION2;
	271
	272	/*
	273	* First entry will be the last update token
	274	* Need to use a char * variable because static
	275	* analysis was suggesting to use strbuf_addbuf
	276	* but we don't want to copy the entire strbuf
6d12b533	277	* only the chars up to the first NUL
8da2c576 KW	278	*/
	279	buf = query_result.buf;
	280	strbuf_addstr(&last_update_token, buf);
	281	if (!last_update_token.len) {
	282	warning("Empty last update token.");
	283	query_success = 0;
	284	} else {
	285	bol = last_update_token.len + 1;
	286	}
	287	} else if (hook_version < 0) {
	288	hook_version = HOOK_INTERFACE_VERSION1;
	289	if (!last_update_token.len)
	290	strbuf_addf(&last_update_token, "%"PRIu64"", last_update);
	291	}
	292	}
	293
	294	if (hook_version == HOOK_INTERFACE_VERSION1) {
	295	query_success = !query_fsmonitor(HOOK_INTERFACE_VERSION1,
	296	istate->fsmonitor_last_update, &query_result);
	297	}
	298
883e248b BP	299	trace_performance_since(last_update, "fsmonitor process '%s'", core_fsmonitor);
	300	trace_printf_key(&trace_fsmonitor, "fsmonitor process '%s' returned %s",
	301	core_fsmonitor, query_success ? "success" : "failure");
	302	}
	303
	304	/* a fsmonitor process can return '/' to indicate all entries are invalid */
8da2c576	305	if (query_success && query_result.buf[bol] != '/') {
883e248b BP	306	/* Mark all entries returned by the monitor as dirty */
883e248b BP	307	buf = query_result.buf;
8da2c576	308	for (i = bol; i < query_result.len; i++) {
883e248b BP	309	if (buf[i] != '\0')
	310	continue;
	311	fsmonitor_refresh_callback(istate, buf + bol);
	312	bol = i + 1;
	313	}
	314	if (bol < query_result.len)
	315	fsmonitor_refresh_callback(istate, buf + bol);
679f2f9f US	316
	317	/* Now mark the untracked cache for fsmonitor usage */
	318	if (istate->untracked)
	319	istate->untracked->use_fsmonitor = 1;
883e248b	320	} else {
679f2f9f US	321
	322	/* We only want to run the post index changed hook if we've actually changed entries, so keep track
	323	* if we actually changed entries or not */
	324	int is_cache_changed = 0;
883e248b	325	/* Mark all entries invalid */
679f2f9f US	326	for (i = 0; i < istate->cache_nr; i++) {
	327	if (istate->cache[i]->ce_flags & CE_FSMONITOR_VALID) {
	328	is_cache_changed = 1;
	329	istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;
	330	}
	331	}
883e248b	332
ca598d5f	333	/* If we're going to check every file, ensure we save the results */
679f2f9f US	334	if (is_cache_changed)
679f2f9f US	335	istate->cache_changed \|= FSMONITOR_CHANGED;
ca598d5f	336
883e248b BP	337	if (istate->untracked)
	338	istate->untracked->use_fsmonitor = 0;
	339	}
	340	strbuf_release(&query_result);
	341
56c69100 KW	342	/* Now that we've updated istate, save the last_update_token */
	343	FREE_AND_NULL(istate->fsmonitor_last_update);
	344	istate->fsmonitor_last_update = strbuf_detach(&last_update_token, NULL);
883e248b BP	345	}
883e248b BP	346
fcd19b09 JH	347	/*
	348	* The caller wants to turn on FSMonitor. And when the caller writes
	349	* the index to disk, a FSMonitor extension should be included. This
	350	* requires that `istate->fsmonitor_last_update` not be NULL. But we
	351	* have not actually talked to a FSMonitor process yet, so we don't
	352	* have an initial value for this field.
	353	*
	354	* For a protocol V1 FSMonitor process, this field is a formatted
	355	* "nanoseconds since epoch" field. However, for a protocol V2
	356	* FSMonitor process, this field is an opaque token.
	357	*
	358	* Historically, `add_fsmonitor()` has initialized this field to the
	359	* current time for protocol V1 processes. There are lots of race
	360	* conditions here, but that code has shipped...
	361	*
	362	* The only true solution is to use a V2 FSMonitor and get a current
	363	* or default token value (that it understands), but we cannot do that
	364	* until we have actually talked to an instance of the FSMonitor process
	365	* (but the protocol requires that we send a token first...).
	366	*
	367	* For simplicity, just initialize like we have a V1 process and require
	368	* that V2 processes adapt.
	369	*/
	370	static void initialize_fsmonitor_last_update(struct index_state *istate)
	371	{
	372	struct strbuf last_update = STRBUF_INIT;
	373
	374	strbuf_addf(&last_update, "%"PRIu64"", getnanotime());
	375	istate->fsmonitor_last_update = strbuf_detach(&last_update, NULL);
	376	}
	377
883e248b BP	378	void add_fsmonitor(struct index_state *istate)
883e248b BP	379	{
5d137fc2	380	unsigned int i;
883e248b BP	381
	382	if (!istate->fsmonitor_last_update) {
	383	trace_printf_key(&trace_fsmonitor, "add fsmonitor");
	384	istate->cache_changed \|= FSMONITOR_CHANGED;
fcd19b09	385	initialize_fsmonitor_last_update(istate);
883e248b BP	386
	387	/* reset the fsmonitor state */
	388	for (i = 0; i < istate->cache_nr; i++)
	389	istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;
	390
	391	/* reset the untracked cache */
	392	if (istate->untracked) {
	393	add_untracked_cache(istate);
	394	istate->untracked->use_fsmonitor = 1;
	395	}
	396
	397	/* Update the fsmonitor state */
	398	refresh_fsmonitor(istate);
	399	}
	400	}
	401
	402	void remove_fsmonitor(struct index_state *istate)
	403	{
	404	if (istate->fsmonitor_last_update) {
	405	trace_printf_key(&trace_fsmonitor, "remove fsmonitor");
	406	istate->cache_changed \|= FSMONITOR_CHANGED;
56c69100	407	FREE_AND_NULL(istate->fsmonitor_last_update);
883e248b BP	408	}
	409	}
	410
	411	void tweak_fsmonitor(struct index_state *istate)
	412	{
5d137fc2	413	unsigned int i;
ba1b9cac AV	414	int fsmonitor_enabled = git_config_get_fsmonitor();
	415
	416	if (istate->fsmonitor_dirty) {
	417	if (fsmonitor_enabled) {
	418	/* Mark all entries valid */
	419	for (i = 0; i < istate->cache_nr; i++) {
	420	istate->cache[i]->ce_flags \|= CE_FSMONITOR_VALID;
	421	}
	422
	423	/* Mark all previously saved entries as dirty */
cae70acf	424	assert_index_minimum(istate, istate->fsmonitor_dirty->bit_size);
ba1b9cac AV	425	ewah_each_bit(istate->fsmonitor_dirty, fsmonitor_ewah_callback, istate);
ba1b9cac AV	426
679f2f9f	427	refresh_fsmonitor(istate);
ba1b9cac AV	428	}
	429
	430	ewah_free(istate->fsmonitor_dirty);
	431	istate->fsmonitor_dirty = NULL;
	432	}
	433
	434	switch (fsmonitor_enabled) {
883e248b BP	435	case -1: /* keep: do nothing */
	436	break;
	437	case 0: /* false */
	438	remove_fsmonitor(istate);
	439	break;
	440	case 1: /* true */
	441	add_fsmonitor(istate);
	442	break;
	443	default: /* unknown value: do nothing */
	444	break;
	445	}
	446	}