[thirdparty/git.git] / trace.c

/*
 * GIT - The information manager from hell
 *
 * Copyright (C) 2000-2002 Michael R. Elkins <me@mutt.org>
 * Copyright (C) 2002-2004 Oswald Buddenhagen <ossi@users.sf.net>
 * Copyright (C) 2004 Theodore Y. Ts'o <tytso@mit.edu>
 * Copyright (C) 2006 Mike McCormack
 * Copyright (C) 2006 Christian Couder
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "cache.h"
#include "quote.h"

/* Get a trace file descriptor from "key" env variable. */
static int get_trace_fd(struct trace_key *key)
{
	static struct trace_key trace_default = { "GIT_TRACE" };
	const char *trace;

	/* use default "GIT_TRACE" if NULL */
	if (!key)
		key = &trace_default;

	/* don't open twice */
	if (key->initialized)
		return key->fd;

	trace = getenv(key->key);

	if (!trace || !strcmp(trace, "") ||
	    !strcmp(trace, "0") || !strcasecmp(trace, "false"))
		key->fd = 0;
	else if (!strcmp(trace, "1") || !strcasecmp(trace, "true"))
		key->fd = STDERR_FILENO;
	else if (strlen(trace) == 1 && isdigit(*trace))
		key->fd = atoi(trace);
	else if (is_absolute_path(trace)) {
		int fd = open(trace, O_WRONLY | O_APPEND | O_CREAT, 0666);
		if (fd == -1) {
			fprintf(stderr,
				"Could not open '%s' for tracing: %s\n"
				"Defaulting to tracing on stderr...\n",
				trace, strerror(errno));
			key->fd = STDERR_FILENO;
		} else {
			key->fd = fd;
			key->need_close = 1;
		}
	} else {
		fprintf(stderr, "What does '%s' for %s mean?\n"
			"If you want to trace into a file, then please set "
			"%s to an absolute pathname (starting with /).\n"
			"Defaulting to tracing on stderr...\n",
			trace, key->key, key->key);
		key->fd = STDERR_FILENO;
	}

	key->initialized = 1;
	return key->fd;
}

void trace_disable(struct trace_key *key)
{
	if (key->need_close)
		close(key->fd);
	key->fd = 0;
	key->initialized = 1;
	key->need_close = 0;
}

static const char err_msg[] = "Could not trace into fd given by "
	"GIT_TRACE environment variable";

static int prepare_trace_line(const char *file, int line,
			      struct trace_key *key, struct strbuf *buf)
{
	static struct trace_key trace_bare = TRACE_KEY_INIT(BARE);
	struct timeval tv;
	struct tm tm;
	time_t secs;

	if (!trace_want(key))
		return 0;

	set_try_to_free_routine(NULL);	/* is never reset */

	/* unit tests may want to disable additional trace output */
	if (trace_want(&trace_bare))
		return 1;

	/* print current timestamp */
	gettimeofday(&tv, NULL);
	secs = tv.tv_sec;
	localtime_r(&secs, &tm);
	strbuf_addf(buf, "%02d:%02d:%02d.%06ld ", tm.tm_hour, tm.tm_min,
		    tm.tm_sec, (long) tv.tv_usec);

#ifdef HAVE_VARIADIC_MACROS
	/* print file:line */
	strbuf_addf(buf, "%s:%d ", file, line);
	/* align trace output (column 40 catches most files names in git) */
	while (buf->len < 40)
		strbuf_addch(buf, ' ');
#endif

	return 1;
}

static void print_trace_line(struct trace_key *key, struct strbuf *buf)
{
	/* append newline if missing */
	if (buf->len && buf->buf[buf->len - 1] != '\n')
		strbuf_addch(buf, '\n');

	write_or_whine_pipe(get_trace_fd(key), buf->buf, buf->len, err_msg);
	strbuf_release(buf);
}

static void trace_vprintf_fl(const char *file, int line, struct trace_key *key,
			     const char *format, va_list ap)
{
	struct strbuf buf = STRBUF_INIT;

	if (!prepare_trace_line(file, line, key, &buf))
		return;

	strbuf_vaddf(&buf, format, ap);
	print_trace_line(key, &buf);
}

static void trace_argv_vprintf_fl(const char *file, int line,
				  const char **argv, const char *format,
				  va_list ap)
{
	struct strbuf buf = STRBUF_INIT;

	if (!prepare_trace_line(file, line, NULL, &buf))
		return;

	strbuf_vaddf(&buf, format, ap);

	sq_quote_argv(&buf, argv, 0);
	print_trace_line(NULL, &buf);
}

void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
		     const struct strbuf *data)
{
	struct strbuf buf = STRBUF_INIT;

	if (!prepare_trace_line(file, line, key, &buf))
		return;

	strbuf_addbuf(&buf, data);
	print_trace_line(key, &buf);
}

static struct trace_key trace_perf_key = TRACE_KEY_INIT(PERFORMANCE);

static void trace_performance_vprintf_fl(const char *file, int line,
					 uint64_t nanos, const char *format,
					 va_list ap)
{
	struct strbuf buf = STRBUF_INIT;

	if (!prepare_trace_line(file, line, &trace_perf_key, &buf))
		return;

	strbuf_addf(&buf, "performance: %.9f s", (double) nanos / 1000000000);

	if (format && *format) {
		strbuf_addstr(&buf, ": ");
		strbuf_vaddf(&buf, format, ap);
	}

	print_trace_line(&trace_perf_key, &buf);
}

#ifndef HAVE_VARIADIC_MACROS

void trace_printf(const char *format, ...)
{
	va_list ap;
	va_start(ap, format);
	trace_vprintf_fl(NULL, 0, NULL, format, ap);
	va_end(ap);
}

void trace_printf_key(struct trace_key *key, const char *format, ...)
{
	va_list ap;
	va_start(ap, format);
	trace_vprintf_fl(NULL, 0, key, format, ap);
	va_end(ap);
}

void trace_argv_printf(const char **argv, const char *format, ...)
{
	va_list ap;
	va_start(ap, format);
	trace_argv_vprintf_fl(NULL, 0, argv, format, ap);
	va_end(ap);
}

void trace_strbuf(const char *key, const struct strbuf *data)
{
	trace_strbuf_fl(NULL, 0, key, data);
}

void trace_performance(uint64_t nanos, const char *format, ...)
{
	va_list ap;
	va_start(ap, format);
	trace_performance_vprintf_fl(NULL, 0, nanos, format, ap);
	va_end(ap);
}

void trace_performance_since(uint64_t start, const char *format, ...)
{
	va_list ap;
	va_start(ap, format);
	trace_performance_vprintf_fl(NULL, 0, getnanotime() - start,
				     format, ap);
	va_end(ap);
}

#else

void trace_printf_key_fl(const char *file, int line, struct trace_key *key,
			 const char *format, ...)
{
	va_list ap;
	va_start(ap, format);
	trace_vprintf_fl(file, line, key, format, ap);
	va_end(ap);
}

void trace_argv_printf_fl(const char *file, int line, const char **argv,
			  const char *format, ...)
{
	va_list ap;
	va_start(ap, format);
	trace_argv_vprintf_fl(file, line, argv, format, ap);
	va_end(ap);
}

void trace_performance_fl(const char *file, int line, uint64_t nanos,
			      const char *format, ...)
{
	va_list ap;
	va_start(ap, format);
	trace_performance_vprintf_fl(file, line, nanos, format, ap);
	va_end(ap);
}

#endif /* HAVE_VARIADIC_MACROS */


static const char *quote_crnl(const char *path)
{
	static char new_path[PATH_MAX];
	const char *p2 = path;
	char *p1 = new_path;

	if (!path)
		return NULL;

	while (*p2) {
		switch (*p2) {
		case '\\': *p1++ = '\\'; *p1++ = '\\'; break;
		case '\n': *p1++ = '\\'; *p1++ = 'n'; break;
		case '\r': *p1++ = '\\'; *p1++ = 'r'; break;
		default:
			*p1++ = *p2;
		}
		p2++;
	}
	*p1 = '\0';
	return new_path;
}

/* FIXME: move prefix to startup_info struct and get rid of this arg */
void trace_repo_setup(const char *prefix)
{
	static struct trace_key key = TRACE_KEY_INIT(SETUP);
	const char *git_work_tree;
	char cwd[PATH_MAX];

	if (!trace_want(&key))
		return;

	if (!getcwd(cwd, PATH_MAX))
		die("Unable to get current working directory");

	if (!(git_work_tree = get_git_work_tree()))
		git_work_tree = "(null)";

	if (!prefix)
		prefix = "(null)";

	trace_printf_key(&key, "setup: git_dir: %s\n", quote_crnl(get_git_dir()));
	trace_printf_key(&key, "setup: worktree: %s\n", quote_crnl(git_work_tree));
	trace_printf_key(&key, "setup: cwd: %s\n", quote_crnl(cwd));
	trace_printf_key(&key, "setup: prefix: %s\n", quote_crnl(prefix));
}

int trace_want(struct trace_key *key)
{
	return !!get_trace_fd(key);
}

#ifdef HAVE_CLOCK_GETTIME

static inline uint64_t highres_nanos(void)
{
	struct timespec ts;
	if (clock_gettime(CLOCK_MONOTONIC, &ts))
		return 0;
	return (uint64_t) ts.tv_sec * 1000000000 + ts.tv_nsec;
}

#elif defined (GIT_WINDOWS_NATIVE)

static inline uint64_t highres_nanos(void)
{
	static uint64_t high_ns, scaled_low_ns;
	static int scale;
	LARGE_INTEGER cnt;

	if (!scale) {
		if (!QueryPerformanceFrequency(&cnt))
			return 0;

		/* high_ns = number of ns per cnt.HighPart */
		high_ns = (1000000000LL << 32) / (uint64_t) cnt.QuadPart;

		/*
		 * Number of ns per cnt.LowPart is 10^9 / frequency (or
		 * high_ns >> 32). For maximum precision, we scale this factor
		 * so that it just fits within 32 bit (i.e. won't overflow if
		 * multiplied with cnt.LowPart).
		 */
		scaled_low_ns = high_ns;
		scale = 32;
		while (scaled_low_ns >= 0x100000000LL) {
			scaled_low_ns >>= 1;
			scale--;
		}
	}

	/* if QPF worked on initialization, we expect QPC to work as well */
	QueryPerformanceCounter(&cnt);

	return (high_ns * cnt.HighPart) +
	       ((scaled_low_ns * cnt.LowPart) >> scale);
}

#else
# define highres_nanos() 0
#endif

static inline uint64_t gettimeofday_nanos(void)
{
	struct timeval tv;
	gettimeofday(&tv, NULL);
	return (uint64_t) tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
}

/*
 * Returns nanoseconds since the epoch (01/01/1970), for performance tracing
 * (i.e. favoring high precision over wall clock time accuracy).
 */
inline uint64_t getnanotime(void)
{
	static uint64_t offset;
	if (offset > 1) {
		/* initialization succeeded, return offset + high res time */
		return offset + highres_nanos();
	} else if (offset == 1) {
		/* initialization failed, fall back to gettimeofday */
		return gettimeofday_nanos();
	} else {
		/* initialize offset if high resolution timer works */
		uint64_t now = gettimeofday_nanos();
		uint64_t highres = highres_nanos();
		if (highres)
			offset = now - highres;
		else
			offset = 1;
		return now;
	}
}
Commit	Line	Data
6ce4e61f CC	1	/*
	2	* GIT - The information manager from hell
	3	*
	4	* Copyright (C) 2000-2002 Michael R. Elkins <me@mutt.org>
	5	* Copyright (C) 2002-2004 Oswald Buddenhagen <ossi@users.sf.net>
	6	* Copyright (C) 2004 Theodore Y. Ts'o <tytso@mit.edu>
	7	* Copyright (C) 2006 Mike McCormack
	8	* Copyright (C) 2006 Christian Couder
	9	*
	10	* This program is free software; you can redistribute it and/or modify
	11	* it under the terms of the GNU General Public License as published by
	12	* the Free Software Foundation; either version 2 of the License, or
	13	* (at your option) any later version.
	14	*
	15	* This program is distributed in the hope that it will be useful,
	16	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	17	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	18	* GNU General Public License for more details.
	19	*
	20	* You should have received a copy of the GNU General Public License
	21	* along with this program; if not, write to the Free Software
	22	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	23	*/
	24
	25	#include "cache.h"
	26	#include "quote.h"
	27
06796607	28	/* Get a trace file descriptor from "key" env variable. */
6aa30857	29	static int get_trace_fd(struct trace_key *key)
6ce4e61f	30	{
6aa30857 KB	31	static struct trace_key trace_default = { "GIT_TRACE" };
	32	const char *trace;
	33
	34	/* use default "GIT_TRACE" if NULL */
	35	if (!key)
	36	key = &trace_default;
	37
	38	/* don't open twice */
	39	if (key->initialized)
	40	return key->fd;
	41
	42	trace = getenv(key->key);
6ce4e61f	43
6844fc80 CC	44	if (!trace \|\| !strcmp(trace, "") \|\|
6844fc80 CC	45	!strcmp(trace, "0") \|\| !strcasecmp(trace, "false"))
6aa30857 KB	46	key->fd = 0;
	47	else if (!strcmp(trace, "1") \|\| !strcasecmp(trace, "true"))
	48	key->fd = STDERR_FILENO;
	49	else if (strlen(trace) == 1 && isdigit(*trace))
	50	key->fd = atoi(trace);
	51	else if (is_absolute_path(trace)) {
6ce4e61f CC	52	int fd = open(trace, O_WRONLY \| O_APPEND \| O_CREAT, 0666);
	53	if (fd == -1) {
	54	fprintf(stderr,
	55	"Could not open '%s' for tracing: %s\n"
	56	"Defaulting to tracing on stderr...\n",
	57	trace, strerror(errno));
6aa30857 KB	58	key->fd = STDERR_FILENO;
	59	} else {
	60	key->fd = fd;
	61	key->need_close = 1;
6ce4e61f	62	}
6aa30857 KB	63	} else {
	64	fprintf(stderr, "What does '%s' for %s mean?\n"
	65	"If you want to trace into a file, then please set "
	66	"%s to an absolute pathname (starting with /).\n"
	67	"Defaulting to tracing on stderr...\n",
	68	trace, key->key, key->key);
	69	key->fd = STDERR_FILENO;
6ce4e61f CC	70	}
6ce4e61f CC	71
6aa30857 KB	72	key->initialized = 1;
	73	return key->fd;
	74	}
6ce4e61f	75
6aa30857 KB	76	void trace_disable(struct trace_key *key)
	77	{
	78	if (key->need_close)
	79	close(key->fd);
	80	key->fd = 0;
	81	key->initialized = 1;
	82	key->need_close = 0;
6ce4e61f CC	83	}
	84
	85	static const char err_msg[] = "Could not trace into fd given by "
	86	"GIT_TRACE environment variable";
	87
e05bed96 KB	88	static int prepare_trace_line(const char *file, int line,
e05bed96 KB	89	struct trace_key key, struct strbuf buf)
c69dfd24	90	{
124647c4	91	static struct trace_key trace_bare = TRACE_KEY_INIT(BARE);
b72be02c KB	92	struct timeval tv;
	93	struct tm tm;
	94	time_t secs;
124647c4	95
c69dfd24 KB	96	if (!trace_want(key))
	97	return 0;
	98
	99	set_try_to_free_routine(NULL); /* is never reset */
	100
124647c4 KB	101	/* unit tests may want to disable additional trace output */
	102	if (trace_want(&trace_bare))
	103	return 1;
	104
b72be02c KB	105	/* print current timestamp */
	106	gettimeofday(&tv, NULL);
	107	secs = tv.tv_sec;
	108	localtime_r(&secs, &tm);
	109	strbuf_addf(buf, "%02d:%02d:%02d.%06ld ", tm.tm_hour, tm.tm_min,
	110	tm.tm_sec, (long) tv.tv_usec);
c69dfd24	111
e05bed96 KB	112	#ifdef HAVE_VARIADIC_MACROS
	113	/* print file:line */
	114	strbuf_addf(buf, "%s:%d ", file, line);
	115	/* align trace output (column 40 catches most files names in git) */
	116	while (buf->len < 40)
	117	strbuf_addch(buf, ' ');
	118	#endif
	119
c69dfd24 KB	120	return 1;
	121	}
	122
	123	static void print_trace_line(struct trace_key key, struct strbuf buf)
	124	{
	125	/* append newline if missing */
	126	if (buf->len && buf->buf[buf->len - 1] != '\n')
	127	strbuf_addch(buf, '\n');
	128
	129	write_or_whine_pipe(get_trace_fd(key), buf->buf, buf->len, err_msg);
	130	strbuf_release(buf);
	131	}
	132
e05bed96 KB	133	static void trace_vprintf_fl(const char file, int line, struct trace_key key,
e05bed96 KB	134	const char *format, va_list ap)
6ce4e61f	135	{
ebeb6090	136	struct strbuf buf = STRBUF_INIT;
6ce4e61f	137
e05bed96	138	if (!prepare_trace_line(file, line, key, &buf))
6ce4e61f CC	139	return;
6ce4e61f CC	140
4a3b0b25	141	strbuf_vaddf(&buf, format, ap);
c69dfd24	142	print_trace_line(key, &buf);
6ce4e61f CC	143	}
6ce4e61f CC	144
e05bed96 KB	145	static void trace_argv_vprintf_fl(const char *file, int line,
	146	const char *argv, const char format,
	147	va_list ap)
06796607	148	{
66f66c59	149	struct strbuf buf = STRBUF_INIT;
06796607	150
e05bed96	151	if (!prepare_trace_line(file, line, NULL, &buf))
66f66c59 KB	152	return;
66f66c59 KB	153
66f66c59	154	strbuf_vaddf(&buf, format, ap);
66f66c59 KB	155
	156	sq_quote_argv(&buf, argv, 0);
	157	print_trace_line(NULL, &buf);
c6053543 JK	158	}
c6053543 JK	159
e05bed96 KB	160	void trace_strbuf_fl(const char file, int line, struct trace_key key,
e05bed96 KB	161	const struct strbuf *data)
94b3b374	162	{
c69dfd24 KB	163	struct strbuf buf = STRBUF_INIT;
c69dfd24 KB	164
e05bed96	165	if (!prepare_trace_line(file, line, key, &buf))
94b3b374 JK	166	return;
94b3b374 JK	167
c69dfd24 KB	168	strbuf_addbuf(&buf, data);
c69dfd24 KB	169	print_trace_line(key, &buf);
94b3b374 JK	170	}
94b3b374 JK	171
09b2c1c7 KB	172	static struct trace_key trace_perf_key = TRACE_KEY_INIT(PERFORMANCE);
	173
	174	static void trace_performance_vprintf_fl(const char *file, int line,
	175	uint64_t nanos, const char *format,
	176	va_list ap)
	177	{
	178	struct strbuf buf = STRBUF_INIT;
	179
	180	if (!prepare_trace_line(file, line, &trace_perf_key, &buf))
	181	return;
	182
	183	strbuf_addf(&buf, "performance: %.9f s", (double) nanos / 1000000000);
	184
	185	if (format && *format) {
	186	strbuf_addstr(&buf, ": ");
	187	strbuf_vaddf(&buf, format, ap);
	188	}
	189
	190	print_trace_line(&trace_perf_key, &buf);
	191	}
	192
e05bed96 KB	193	#ifndef HAVE_VARIADIC_MACROS
e05bed96 KB	194
66f66c59	195	void trace_printf(const char *format, ...)
6ce4e61f	196	{
19247e55	197	va_list ap;
4a3b0b25	198	va_start(ap, format);
e05bed96	199	trace_vprintf_fl(NULL, 0, NULL, format, ap);
19247e55	200	va_end(ap);
66f66c59	201	}
6ce4e61f	202
66f66c59 KB	203	void trace_printf_key(struct trace_key key, const char format, ...)
	204	{
	205	va_list ap;
	206	va_start(ap, format);
e05bed96 KB	207	trace_vprintf_fl(NULL, 0, key, format, ap);
	208	va_end(ap);
	209	}
	210
	211	void trace_argv_printf(const char *argv, const char format, ...)
	212	{
	213	va_list ap;
	214	va_start(ap, format);
	215	trace_argv_vprintf_fl(NULL, 0, argv, format, ap);
66f66c59	216	va_end(ap);
6ce4e61f	217	}
a9ca8a85	218
e05bed96 KB	219	void trace_strbuf(const char key, const struct strbuf data)
	220	{
	221	trace_strbuf_fl(NULL, 0, key, data);
	222	}
	223
09b2c1c7 KB	224	void trace_performance(uint64_t nanos, const char *format, ...)
	225	{
	226	va_list ap;
	227	va_start(ap, format);
	228	trace_performance_vprintf_fl(NULL, 0, nanos, format, ap);
	229	va_end(ap);
	230	}
	231
	232	void trace_performance_since(uint64_t start, const char *format, ...)
	233	{
	234	va_list ap;
	235	va_start(ap, format);
	236	trace_performance_vprintf_fl(NULL, 0, getnanotime() - start,
	237	format, ap);
	238	va_end(ap);
	239	}
	240
e05bed96 KB	241	#else
	242
	243	void trace_printf_key_fl(const char file, int line, struct trace_key key,
	244	const char *format, ...)
	245	{
	246	va_list ap;
	247	va_start(ap, format);
	248	trace_vprintf_fl(file, line, key, format, ap);
	249	va_end(ap);
	250	}
	251
	252	void trace_argv_printf_fl(const char file, int line, const char *argv,
	253	const char *format, ...)
	254	{
	255	va_list ap;
	256	va_start(ap, format);
	257	trace_argv_vprintf_fl(file, line, argv, format, ap);
	258	va_end(ap);
	259	}
	260
09b2c1c7 KB	261	void trace_performance_fl(const char *file, int line, uint64_t nanos,
	262	const char *format, ...)
	263	{
	264	va_list ap;
	265	va_start(ap, format);
	266	trace_performance_vprintf_fl(file, line, nanos, format, ap);
	267	va_end(ap);
	268	}
	269
e05bed96 KB	270	#endif /* HAVE_VARIADIC_MACROS */
	271
	272
a9ca8a85 NTND	273	static const char quote_crnl(const char path)
	274	{
	275	static char new_path[PATH_MAX];
	276	const char *p2 = path;
	277	char *p1 = new_path;
	278
	279	if (!path)
	280	return NULL;
	281
	282	while (*p2) {
	283	switch (*p2) {
	284	case '\\': p1++ = '\\'; p1++ = '\\'; break;
	285	case '\n': p1++ = '\\'; p1++ = 'n'; break;
	286	case '\r': p1++ = '\\'; p1++ = 'r'; break;
	287	default:
	288	p1++ = p2;
	289	}
	290	p2++;
	291	}
	292	*p1 = '\0';
	293	return new_path;
	294	}
	295
	296	/* FIXME: move prefix to startup_info struct and get rid of this arg */
	297	void trace_repo_setup(const char *prefix)
	298	{
6aa30857	299	static struct trace_key key = TRACE_KEY_INIT(SETUP);
e83c267f	300	const char *git_work_tree;
a9ca8a85	301	char cwd[PATH_MAX];
a9ca8a85	302
6aa30857	303	if (!trace_want(&key))
a9ca8a85 NTND	304	return;
	305
	306	if (!getcwd(cwd, PATH_MAX))
	307	die("Unable to get current working directory");
	308
e83c267f BC	309	if (!(git_work_tree = get_git_work_tree()))
	310	git_work_tree = "(null)";
	311
	312	if (!prefix)
	313	prefix = "(null)";
	314
6aa30857 KB	315	trace_printf_key(&key, "setup: git_dir: %s\n", quote_crnl(get_git_dir()));
	316	trace_printf_key(&key, "setup: worktree: %s\n", quote_crnl(git_work_tree));
	317	trace_printf_key(&key, "setup: cwd: %s\n", quote_crnl(cwd));
	318	trace_printf_key(&key, "setup: prefix: %s\n", quote_crnl(prefix));
a9ca8a85	319	}
39bc5e46	320
6aa30857	321	int trace_want(struct trace_key *key)
39bc5e46	322	{
6aa30857	323	return !!get_trace_fd(key);
39bc5e46	324	}
148d6771 KB	325
	326	#ifdef HAVE_CLOCK_GETTIME
	327
	328	static inline uint64_t highres_nanos(void)
	329	{
	330	struct timespec ts;
	331	if (clock_gettime(CLOCK_MONOTONIC, &ts))
	332	return 0;
	333	return (uint64_t) ts.tv_sec * 1000000000 + ts.tv_nsec;
	334	}
	335
	336	#elif defined (GIT_WINDOWS_NATIVE)
	337
	338	static inline uint64_t highres_nanos(void)
	339	{
	340	static uint64_t high_ns, scaled_low_ns;
	341	static int scale;
	342	LARGE_INTEGER cnt;
	343
	344	if (!scale) {
	345	if (!QueryPerformanceFrequency(&cnt))
	346	return 0;
	347
	348	/* high_ns = number of ns per cnt.HighPart */
	349	high_ns = (1000000000LL << 32) / (uint64_t) cnt.QuadPart;
	350
	351	/*
	352	* Number of ns per cnt.LowPart is 10^9 / frequency (or
	353	* high_ns >> 32). For maximum precision, we scale this factor
	354	* so that it just fits within 32 bit (i.e. won't overflow if
	355	* multiplied with cnt.LowPart).
	356	*/
	357	scaled_low_ns = high_ns;
	358	scale = 32;
	359	while (scaled_low_ns >= 0x100000000LL) {
	360	scaled_low_ns >>= 1;
	361	scale--;
	362	}
	363	}
	364
	365	/* if QPF worked on initialization, we expect QPC to work as well */
	366	QueryPerformanceCounter(&cnt);
	367
	368	return (high_ns * cnt.HighPart) +
	369	((scaled_low_ns * cnt.LowPart) >> scale);
	370	}
	371
	372	#else
	373	# define highres_nanos() 0
	374	#endif
	375
	376	static inline uint64_t gettimeofday_nanos(void)
	377	{
	378	struct timeval tv;
	379	gettimeofday(&tv, NULL);
	380	return (uint64_t) tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
	381	}
	382
	383	/*
	384	* Returns nanoseconds since the epoch (01/01/1970), for performance tracing
	385	* (i.e. favoring high precision over wall clock time accuracy).
	386	*/
	387	inline uint64_t getnanotime(void)
	388	{
389	static uint64_t offset;
390	if (offset > 1) {
391	/* initialization succeeded, return offset + high res time */
392	return offset + highres_nanos();
393	} else if (offset == 1) {
394	/* initialization failed, fall back to gettimeofday */
395	return gettimeofday_nanos();
396	} else {
397	/* initialize offset if high resolution timer works */
398	uint64_t now = gettimeofday_nanos();
399	uint64_t highres = highres_nanos();
400	if (highres)
401	offset = now - highres;
402	else
403	offset = 1;
404	return now;
405	}
406	}