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

	if (pos >= istate->cache_nr)
		BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" >= %u)",
		    (uintmax_t)pos, istate->cache_nr);

	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 &&
	    istate->fsmonitor_dirty->bit_size > istate->cache_nr)
		BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
		    (uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr);

	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 &&
	    istate->fsmonitor_dirty->bit_size > istate->cache_nr)
		BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
		    (uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr);

	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 */
			if (istate->fsmonitor_dirty->bit_size > istate->cache_nr)
				BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
				    (uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr);
			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
	16	static void fsmonitor_ewah_callback(size_t pos, void *is)
	17	{
	18	struct index_state istate = (struct index_state )is;
3444ec2e	19	struct cache_entry *ce;
883e248b	20
3444ec2e WB	21	if (pos >= istate->cache_nr)
	22	BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" >= %u)",
	23	(uintmax_t)pos, istate->cache_nr);
	24
	25	ce = istate->cache[pos];
883e248b BP	26	ce->ce_flags &= ~CE_FSMONITOR_VALID;
	27	}
	28
8da2c576 KW	29	static int fsmonitor_hook_version(void)
	30	{
	31	int hook_version;
	32
	33	if (git_config_get_int("core.fsmonitorhookversion", &hook_version))
	34	return -1;
	35
	36	if (hook_version == HOOK_INTERFACE_VERSION1 \|\|
	37	hook_version == HOOK_INTERFACE_VERSION2)
	38	return hook_version;
	39
	40	warning("Invalid hook version '%i' in core.fsmonitorhookversion. "
	41	"Must be 1 or 2.", hook_version);
	42	return -1;
	43	}
	44
883e248b BP	45	int read_fsmonitor_extension(struct index_state istate, const void data,
	46	unsigned long sz)
	47	{
	48	const char *index = data;
	49	uint32_t hdr_version;
	50	uint32_t ewah_size;
	51	struct ewah_bitmap *fsmonitor_dirty;
883e248b	52	int ret;
56c69100 KW	53	uint64_t timestamp;
56c69100 KW	54	struct strbuf last_update = STRBUF_INIT;
883e248b	55
56c69100	56	if (sz < sizeof(uint32_t) + 1 + sizeof(uint32_t))
883e248b BP	57	return error("corrupt fsmonitor extension (too short)");
	58
	59	hdr_version = get_be32(index);
	60	index += sizeof(uint32_t);
56c69100 KW	61	if (hdr_version == INDEX_EXTENSION_VERSION1) {
	62	timestamp = get_be64(index);
	63	strbuf_addf(&last_update, "%"PRIu64"", timestamp);
	64	index += sizeof(uint64_t);
	65	} else if (hdr_version == INDEX_EXTENSION_VERSION2) {
	66	strbuf_addstr(&last_update, index);
	67	index += last_update.len + 1;
	68	} else {
883e248b	69	return error("bad fsmonitor version %d", hdr_version);
56c69100	70	}
883e248b	71
56c69100	72	istate->fsmonitor_last_update = strbuf_detach(&last_update, NULL);
883e248b BP	73
	74	ewah_size = get_be32(index);
	75	index += sizeof(uint32_t);
	76
	77	fsmonitor_dirty = ewah_new();
	78	ret = ewah_read_mmap(fsmonitor_dirty, index, ewah_size);
	79	if (ret != ewah_size) {
	80	ewah_free(fsmonitor_dirty);
	81	return error("failed to parse ewah bitmap reading fsmonitor index extension");
	82	}
ba1b9cac	83	istate->fsmonitor_dirty = fsmonitor_dirty;
883e248b	84
61eea521 JH	85	if (!istate->split_index &&
61eea521 JH	86	istate->fsmonitor_dirty->bit_size > istate->cache_nr)
3444ec2e WB	87	BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
	88	(uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr);
	89
29fbbf43 JH	90	trace2_data_string("index", NULL, "extension/fsmn/read/token",
	91	istate->fsmonitor_last_update);
	92	trace_printf_key(&trace_fsmonitor,
	93	"read fsmonitor extension successful '%s'",
	94	istate->fsmonitor_last_update);
883e248b BP	95	return 0;
	96	}
	97
3bd28eb2 AV	98	void fill_fsmonitor_bitmap(struct index_state *istate)
3bd28eb2 AV	99	{
3444ec2e	100	unsigned int i, skipped = 0;
3bd28eb2	101	istate->fsmonitor_dirty = ewah_new();
3444ec2e WB	102	for (i = 0; i < istate->cache_nr; i++) {
	103	if (istate->cache[i]->ce_flags & CE_REMOVE)
	104	skipped++;
	105	else if (!(istate->cache[i]->ce_flags & CE_FSMONITOR_VALID))
	106	ewah_set(istate->fsmonitor_dirty, i - skipped);
	107	}
3bd28eb2 AV	108	}
3bd28eb2 AV	109
883e248b BP	110	void write_fsmonitor_extension(struct strbuf sb, struct index_state istate)
	111	{
	112	uint32_t hdr_version;
883e248b BP	113	uint32_t ewah_start;
	114	uint32_t ewah_size = 0;
	115	int fixup = 0;
	116
61eea521 JH	117	if (!istate->split_index &&
61eea521 JH	118	istate->fsmonitor_dirty->bit_size > istate->cache_nr)
3444ec2e WB	119	BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
	120	(uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr);
	121
56c69100	122	put_be32(&hdr_version, INDEX_EXTENSION_VERSION2);
883e248b BP	123	strbuf_add(sb, &hdr_version, sizeof(uint32_t));
883e248b BP	124
56c69100 KW	125	strbuf_addstr(sb, istate->fsmonitor_last_update);
	126	strbuf_addch(sb, 0); /* Want to keep a NUL */
	127
883e248b BP	128	fixup = sb->len;
	129	strbuf_add(sb, &ewah_size, sizeof(uint32_t)); /* we'll fix this up later */
	130
	131	ewah_start = sb->len;
3bd28eb2 AV	132	ewah_serialize_strbuf(istate->fsmonitor_dirty, sb);
	133	ewah_free(istate->fsmonitor_dirty);
	134	istate->fsmonitor_dirty = NULL;
883e248b BP	135
	136	/* fix up size field */
	137	put_be32(&ewah_size, sb->len - ewah_start);
	138	memcpy(sb->buf + fixup, &ewah_size, sizeof(uint32_t));
	139
29fbbf43 JH	140	trace2_data_string("index", NULL, "extension/fsmn/write/token",
	141	istate->fsmonitor_last_update);
	142	trace_printf_key(&trace_fsmonitor,
	143	"write fsmonitor extension successful '%s'",
	144	istate->fsmonitor_last_update);
883e248b BP	145	}
	146
	147	/*
56c69100	148	* Call the query-fsmonitor hook passing the last update token of the saved results.
883e248b	149	*/
56c69100	150	static int query_fsmonitor(int version, const char last_update, struct strbuf query_result)
883e248b BP	151	{
883e248b BP	152	struct child_process cp = CHILD_PROCESS_INIT;
940b94f3	153	int result;
883e248b	154
735e4173	155	if (!core_fsmonitor)
883e248b BP	156	return -1;
883e248b BP	157
ef8d7ac4 JK	158	strvec_push(&cp.args, core_fsmonitor);
	159	strvec_pushf(&cp.args, "%d", version);
	160	strvec_pushf(&cp.args, "%s", last_update);
883e248b	161	cp.use_shell = 1;
11cf33be	162	cp.dir = get_git_work_tree();
883e248b	163
940b94f3 JH	164	trace2_region_enter("fsm_hook", "query", NULL);
	165
	166	result = capture_command(&cp, query_result, 1024);
	167
	168	if (result)
	169	trace2_data_intmax("fsm_hook", NULL, "query/failed", result);
	170	else {
	171	trace2_data_intmax("fsm_hook", NULL, "query/response-length",
	172	query_result->len);
	173
	174	if (fsmonitor_is_trivial_response(query_result))
	175	trace2_data_intmax("fsm_hook", NULL,
	176	"query/trivial-response", 1);
	177	}
	178
	179	trace2_region_leave("fsm_hook", "query", NULL);
	180
	181	return result;
	182	}
	183
	184	int fsmonitor_is_trivial_response(const struct strbuf *query_result)
	185	{
	186	static char trivial_response[3] = { '\0', '/', '\0' };
940b94f3	187
097ea2c8 AH	188	return query_result->len >= 3 &&
	189	!memcmp(trivial_response,
	190	&query_result->buf[query_result->len - 3], 3);
883e248b BP	191	}
883e248b BP	192
ff03836b	193	static void fsmonitor_refresh_callback(struct index_state istate, char name)
883e248b	194	{
ff03836b KW	195	int i, len = strlen(name);
	196	if (name[len - 1] == '/') {
	197
	198	/*
	199	* TODO We should binary search to find the first path with
	200	* TODO this directory prefix. Then linearly update entries
	201	* TODO while the prefix matches. Taking care to search without
	202	* TODO the trailing slash -- because '/' sorts after a few
	203	* TODO interesting special chars, like '.' and ' '.
	204	*/
	205
	206	/* Mark all entries for the folder invalid */
	207	for (i = 0; i < istate->cache_nr; i++) {
	208	if (istate->cache[i]->ce_flags & CE_FSMONITOR_VALID &&
	209	starts_with(istate->cache[i]->name, name))
	210	istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;
	211	}
	212	/* Need to remove the / from the path for the untracked cache */
	213	name[len - 1] = '\0';
	214	} else {
	215	int pos = index_name_pos(istate, name, strlen(name));
883e248b	216
ff03836b KW	217	if (pos >= 0) {
	218	struct cache_entry *ce = istate->cache[pos];
	219	ce->ce_flags &= ~CE_FSMONITOR_VALID;
	220	}
883e248b BP	221	}
	222
	223	/*
	224	* Mark the untracked cache dirty even if it wasn't found in the index
	225	* as it could be a new untracked file.
	226	*/
	227	trace_printf_key(&trace_fsmonitor, "fsmonitor_refresh_callback '%s'", name);
0cacebf0	228	untracked_cache_invalidate_path(istate, name, 0);
883e248b BP	229	}
	230
	231	void refresh_fsmonitor(struct index_state *istate)
	232	{
883e248b	233	struct strbuf query_result = STRBUF_INIT;
8da2c576 KW	234	int query_success = 0, hook_version = -1;
8da2c576 KW	235	size_t bol = 0; /* beginning of line */
883e248b	236	uint64_t last_update;
56c69100	237	struct strbuf last_update_token = STRBUF_INIT;
883e248b	238	char *buf;
5d137fc2	239	unsigned int i;
883e248b	240
398a3b08	241	if (!core_fsmonitor \|\| istate->fsmonitor_has_run_once)
883e248b	242	return;
8da2c576 KW	243
	244	hook_version = fsmonitor_hook_version();
	245
398a3b08	246	istate->fsmonitor_has_run_once = 1;
883e248b BP	247
	248	trace_printf_key(&trace_fsmonitor, "refresh fsmonitor");
	249	/*
	250	* This could be racy so save the date/time now and query_fsmonitor
	251	* should be inclusive to ensure we don't miss potential changes.
	252	*/
	253	last_update = getnanotime();
8da2c576 KW	254	if (hook_version == HOOK_INTERFACE_VERSION1)
8da2c576 KW	255	strbuf_addf(&last_update_token, "%"PRIu64"", last_update);
883e248b BP	256
883e248b BP	257	/*
8da2c576 KW	258	* If we have a last update token, call query_fsmonitor for the set of
8da2c576 KW	259	* changes since that token, else assume everything is possibly dirty
883e248b BP	260	* and check it all.
	261	*/
	262	if (istate->fsmonitor_last_update) {
8da2c576 KW	263	if (hook_version == -1 \|\| hook_version == HOOK_INTERFACE_VERSION2) {
	264	query_success = !query_fsmonitor(HOOK_INTERFACE_VERSION2,
	265	istate->fsmonitor_last_update, &query_result);
	266
	267	if (query_success) {
	268	if (hook_version < 0)
	269	hook_version = HOOK_INTERFACE_VERSION2;
	270
	271	/*
	272	* First entry will be the last update token
	273	* Need to use a char * variable because static
	274	* analysis was suggesting to use strbuf_addbuf
	275	* but we don't want to copy the entire strbuf
6d12b533	276	* only the chars up to the first NUL
8da2c576 KW	277	*/
	278	buf = query_result.buf;
	279	strbuf_addstr(&last_update_token, buf);
	280	if (!last_update_token.len) {
	281	warning("Empty last update token.");
	282	query_success = 0;
	283	} else {
	284	bol = last_update_token.len + 1;
	285	}
	286	} else if (hook_version < 0) {
	287	hook_version = HOOK_INTERFACE_VERSION1;
	288	if (!last_update_token.len)
	289	strbuf_addf(&last_update_token, "%"PRIu64"", last_update);
	290	}
	291	}
	292
	293	if (hook_version == HOOK_INTERFACE_VERSION1) {
	294	query_success = !query_fsmonitor(HOOK_INTERFACE_VERSION1,
	295	istate->fsmonitor_last_update, &query_result);
	296	}
	297
883e248b BP	298	trace_performance_since(last_update, "fsmonitor process '%s'", core_fsmonitor);
	299	trace_printf_key(&trace_fsmonitor, "fsmonitor process '%s' returned %s",
	300	core_fsmonitor, query_success ? "success" : "failure");
	301	}
	302
	303	/* a fsmonitor process can return '/' to indicate all entries are invalid */
8da2c576	304	if (query_success && query_result.buf[bol] != '/') {
883e248b BP	305	/* Mark all entries returned by the monitor as dirty */
883e248b BP	306	buf = query_result.buf;
8da2c576	307	for (i = bol; i < query_result.len; i++) {
883e248b BP	308	if (buf[i] != '\0')
	309	continue;
	310	fsmonitor_refresh_callback(istate, buf + bol);
	311	bol = i + 1;
	312	}
	313	if (bol < query_result.len)
	314	fsmonitor_refresh_callback(istate, buf + bol);
679f2f9f US	315
	316	/* Now mark the untracked cache for fsmonitor usage */
	317	if (istate->untracked)
	318	istate->untracked->use_fsmonitor = 1;
883e248b	319	} else {
679f2f9f US	320
	321	/* We only want to run the post index changed hook if we've actually changed entries, so keep track
	322	* if we actually changed entries or not */
	323	int is_cache_changed = 0;
883e248b	324	/* Mark all entries invalid */
679f2f9f US	325	for (i = 0; i < istate->cache_nr; i++) {
	326	if (istate->cache[i]->ce_flags & CE_FSMONITOR_VALID) {
	327	is_cache_changed = 1;
	328	istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;
	329	}
	330	}
883e248b	331
ca598d5f	332	/* If we're going to check every file, ensure we save the results */
679f2f9f US	333	if (is_cache_changed)
679f2f9f US	334	istate->cache_changed \|= FSMONITOR_CHANGED;
ca598d5f	335
883e248b BP	336	if (istate->untracked)
	337	istate->untracked->use_fsmonitor = 0;
	338	}
	339	strbuf_release(&query_result);
	340
56c69100 KW	341	/* Now that we've updated istate, save the last_update_token */
	342	FREE_AND_NULL(istate->fsmonitor_last_update);
	343	istate->fsmonitor_last_update = strbuf_detach(&last_update_token, NULL);
883e248b BP	344	}
883e248b BP	345
fcd19b09 JH	346	/*
	347	* The caller wants to turn on FSMonitor. And when the caller writes
	348	* the index to disk, a FSMonitor extension should be included. This
	349	* requires that `istate->fsmonitor_last_update` not be NULL. But we
	350	* have not actually talked to a FSMonitor process yet, so we don't
	351	* have an initial value for this field.
	352	*
	353	* For a protocol V1 FSMonitor process, this field is a formatted
	354	* "nanoseconds since epoch" field. However, for a protocol V2
	355	* FSMonitor process, this field is an opaque token.
	356	*
	357	* Historically, `add_fsmonitor()` has initialized this field to the
	358	* current time for protocol V1 processes. There are lots of race
	359	* conditions here, but that code has shipped...
	360	*
	361	* The only true solution is to use a V2 FSMonitor and get a current
	362	* or default token value (that it understands), but we cannot do that
	363	* until we have actually talked to an instance of the FSMonitor process
	364	* (but the protocol requires that we send a token first...).
	365	*
	366	* For simplicity, just initialize like we have a V1 process and require
	367	* that V2 processes adapt.
	368	*/
	369	static void initialize_fsmonitor_last_update(struct index_state *istate)
	370	{
	371	struct strbuf last_update = STRBUF_INIT;
	372
	373	strbuf_addf(&last_update, "%"PRIu64"", getnanotime());
	374	istate->fsmonitor_last_update = strbuf_detach(&last_update, NULL);
	375	}
	376
883e248b BP	377	void add_fsmonitor(struct index_state *istate)
883e248b BP	378	{
5d137fc2	379	unsigned int i;
883e248b BP	380
	381	if (!istate->fsmonitor_last_update) {
	382	trace_printf_key(&trace_fsmonitor, "add fsmonitor");
	383	istate->cache_changed \|= FSMONITOR_CHANGED;
fcd19b09	384	initialize_fsmonitor_last_update(istate);
883e248b BP	385
	386	/* reset the fsmonitor state */
	387	for (i = 0; i < istate->cache_nr; i++)
	388	istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;
	389
	390	/* reset the untracked cache */
	391	if (istate->untracked) {
	392	add_untracked_cache(istate);
	393	istate->untracked->use_fsmonitor = 1;
	394	}
	395
	396	/* Update the fsmonitor state */
	397	refresh_fsmonitor(istate);
	398	}
	399	}
	400
	401	void remove_fsmonitor(struct index_state *istate)
	402	{
	403	if (istate->fsmonitor_last_update) {
	404	trace_printf_key(&trace_fsmonitor, "remove fsmonitor");
	405	istate->cache_changed \|= FSMONITOR_CHANGED;
56c69100	406	FREE_AND_NULL(istate->fsmonitor_last_update);
883e248b BP	407	}
	408	}
	409
	410	void tweak_fsmonitor(struct index_state *istate)
	411	{
5d137fc2	412	unsigned int i;
ba1b9cac AV	413	int fsmonitor_enabled = git_config_get_fsmonitor();
	414
	415	if (istate->fsmonitor_dirty) {
	416	if (fsmonitor_enabled) {
	417	/* Mark all entries valid */
	418	for (i = 0; i < istate->cache_nr; i++) {
	419	istate->cache[i]->ce_flags \|= CE_FSMONITOR_VALID;
	420	}
	421
	422	/* Mark all previously saved entries as dirty */
3444ec2e WB	423	if (istate->fsmonitor_dirty->bit_size > istate->cache_nr)
	424	BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
	425	(uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr);
ba1b9cac AV	426	ewah_each_bit(istate->fsmonitor_dirty, fsmonitor_ewah_callback, istate);
ba1b9cac AV	427
679f2f9f	428	refresh_fsmonitor(istate);
ba1b9cac AV	429	}
	430
	431	ewah_free(istate->fsmonitor_dirty);
	432	istate->fsmonitor_dirty = NULL;
	433	}
	434
	435	switch (fsmonitor_enabled) {
883e248b BP	436	case -1: /* keep: do nothing */
	437	break;
	438	case 0: /* false */
	439	remove_fsmonitor(istate);
	440	break;
	441	case 1: /* true */
	442	add_fsmonitor(istate);
	443	break;
	444	default: /* unknown value: do nothing */
	445	break;
	446	}
	447	}