git

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/*
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 * GIT - The information manager from hell
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 *
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 * Copyright (C) 2000-2002 Michael R. Elkins <me@mutt.org>
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 * Copyright (C) 2002-2004 Oswald Buddenhagen <ossi@users.sf.net>
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 * Copyright (C) 2004 Theodore Y. Ts'o <tytso@mit.edu>
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 * Copyright (C) 2006 Mike McCormack
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 * Copyright (C) 2006 Christian Couder
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 *
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 *  This program is free software; you can redistribute it and/or modify
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 *  it under the terms of the GNU General Public License as published by
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 *  the Free Software Foundation; either version 2 of the License, or
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 *  (at your option) any later version.
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 *
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 *  This program is distributed in the hope that it will be useful,
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 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
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 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 *  GNU General Public License for more details.
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 *
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 *  You should have received a copy of the GNU General Public License
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 *  along with this program; if not, see <https://www.gnu.org/licenses/>.
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 */
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#include "git-compat-util.h"
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#include "abspath.h"
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#include "environment.h"
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#include "quote.h"
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#include "setup.h"
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#include "trace.h"
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struct trace_key trace_default_key = { "GIT_TRACE", 0, 0, 0 };
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struct trace_key trace_perf_key = TRACE_KEY_INIT(PERFORMANCE);
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struct trace_key trace_setup_key = TRACE_KEY_INIT(SETUP);
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/* Get a trace file descriptor from "key" env variable. */
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static int get_trace_fd(struct trace_key *key, const char *override_envvar)
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{
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	const char *trace;
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	/* don't open twice */
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	if (key->initialized)
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		return key->fd;
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	trace = override_envvar ? override_envvar : getenv(key->key);
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	if (!trace || !strcmp(trace, "") ||
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	    !strcmp(trace, "0") || !strcasecmp(trace, "false"))
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		key->fd = 0;
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	else if (!strcmp(trace, "1") || !strcasecmp(trace, "true"))
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		key->fd = STDERR_FILENO;
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	else if (strlen(trace) == 1 && isdigit(*trace))
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		key->fd = atoi(trace);
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	else if (is_absolute_path(trace)) {
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		int fd = open(trace, O_WRONLY | O_APPEND | O_CREAT, 0666);
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		if (fd == -1) {
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			warning("could not open '%s' for tracing: %s",
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				trace, strerror(errno));
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			trace_disable(key);
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		} else {
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			key->fd = fd;
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			key->need_close = 1;
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		}
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	} else {
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		warning("unknown trace value for '%s': %s\n"
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			"         If you want to trace into a file, then please set %s\n"
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			"         to an absolute pathname (starting with /)",
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			key->key, trace, key->key);
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		trace_disable(key);
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	}
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	key->initialized = 1;
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	return key->fd;
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}
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void trace_override_envvar(struct trace_key *key, const char *value)
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{
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	trace_disable(key);
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	key->initialized = 0;
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	/*
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	 * Invoke get_trace_fd() to initialize key using the given value
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	 * instead of the value of the environment variable.
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	 */
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	get_trace_fd(key, value);
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}
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void trace_disable(struct trace_key *key)
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{
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	if (key->need_close)
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		close(key->fd);
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	key->fd = 0;
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	key->initialized = 1;
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	key->need_close = 0;
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}
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static int prepare_trace_line(const char *file, int line,
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			      struct trace_key *key, struct strbuf *buf)
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{
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	static struct trace_key trace_bare = TRACE_KEY_INIT(BARE);
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	struct timeval tv;
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	struct tm tm;
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	time_t secs;
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	if (!trace_want(key))
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		return 0;
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	/* unit tests may want to disable additional trace output */
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	if (trace_want(&trace_bare))
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		return 1;
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	/* print current timestamp */
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	gettimeofday(&tv, NULL);
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	secs = tv.tv_sec;
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	localtime_r(&secs, &tm);
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	strbuf_addf(buf, "%02d:%02d:%02d.%06ld %s:%d", tm.tm_hour, tm.tm_min,
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		    tm.tm_sec, (long) tv.tv_usec, file, line);
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	/* align trace output (column 40 catches most files names in git) */
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	while (buf->len < 40)
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		strbuf_addch(buf, ' ');
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	return 1;
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}
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static void trace_write(struct trace_key *key, const void *buf, unsigned len)
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{
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	if (write_in_full(get_trace_fd(key, NULL), buf, len) < 0) {
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		warning("unable to write trace for %s: %s",
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			key->key, strerror(errno));
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		trace_disable(key);
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	}
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}
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void trace_verbatim(struct trace_key *key, const void *buf, unsigned len)
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{
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	if (!trace_want(key))
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		return;
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	trace_write(key, buf, len);
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}
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static void print_trace_line(struct trace_key *key, struct strbuf *buf)
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{
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	strbuf_complete_line(buf);
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	trace_write(key, buf->buf, buf->len);
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}
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static void trace_vprintf_fl(const char *file, int line, struct trace_key *key,
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			     const char *format, va_list ap)
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{
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	struct strbuf buf = STRBUF_INIT;
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	if (!prepare_trace_line(file, line, key, &buf))
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		return;
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	strbuf_vaddf(&buf, format, ap);
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	print_trace_line(key, &buf);
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	strbuf_release(&buf);
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}
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static void trace_argv_vprintf_fl(const char *file, int line,
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				  const char **argv, const char *format,
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				  va_list ap)
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{
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	struct strbuf buf = STRBUF_INIT;
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	if (!prepare_trace_line(file, line, &trace_default_key, &buf))
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		return;
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	strbuf_vaddf(&buf, format, ap);
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	sq_quote_argv_pretty(&buf, argv);
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	print_trace_line(&trace_default_key, &buf);
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	strbuf_release(&buf);
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}
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void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
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		     const struct strbuf *data)
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{
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	struct strbuf buf = STRBUF_INIT;
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	if (!prepare_trace_line(file, line, key, &buf))
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		return;
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	strbuf_addbuf(&buf, data);
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	print_trace_line(key, &buf);
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	strbuf_release(&buf);
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}
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static uint64_t perf_start_times[10];
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static int perf_indent;
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uint64_t trace_performance_enter(void)
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{
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	uint64_t now;
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	if (!trace_want(&trace_perf_key))
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		return 0;
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	now = getnanotime();
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	perf_start_times[perf_indent] = now;
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	if (perf_indent + 1 < ARRAY_SIZE(perf_start_times))
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		perf_indent++;
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	else
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		BUG("Too deep indentation");
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	return now;
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}
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static void trace_performance_vprintf_fl(const char *file, int line,
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					 uint64_t nanos, const char *format,
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					 va_list ap)
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{
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	static const char space[] = "          ";
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	struct strbuf buf = STRBUF_INIT;
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	if (!prepare_trace_line(file, line, &trace_perf_key, &buf))
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		return;
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	strbuf_addf(&buf, "performance: %.9f s", (double) nanos / 1000000000);
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	if (format && *format) {
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		if (perf_indent >= strlen(space))
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			BUG("Too deep indentation");
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		strbuf_addf(&buf, ":%.*s ", perf_indent, space);
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		strbuf_vaddf(&buf, format, ap);
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	}
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	print_trace_line(&trace_perf_key, &buf);
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	strbuf_release(&buf);
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}
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void trace_printf_key_fl(const char *file, int line, struct trace_key *key,
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			 const char *format, ...)
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{
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	va_list ap;
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	va_start(ap, format);
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	trace_vprintf_fl(file, line, key, format, ap);
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	va_end(ap);
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}
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void trace_argv_printf_fl(const char *file, int line, const char **argv,
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			  const char *format, ...)
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{
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	va_list ap;
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	va_start(ap, format);
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	trace_argv_vprintf_fl(file, line, argv, format, ap);
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	va_end(ap);
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}
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void trace_performance_fl(const char *file, int line, uint64_t nanos,
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			      const char *format, ...)
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{
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	va_list ap;
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	va_start(ap, format);
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	trace_performance_vprintf_fl(file, line, nanos, format, ap);
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	va_end(ap);
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}
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void trace_performance_leave_fl(const char *file, int line,
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				uint64_t nanos, const char *format, ...)
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{
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	va_list ap;
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	uint64_t since;
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	if (perf_indent)
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		perf_indent--;
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	if (!format) /* Allow callers to leave without tracing anything */
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		return;
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	since = perf_start_times[perf_indent];
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	va_start(ap, format);
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	trace_performance_vprintf_fl(file, line, nanos - since, format, ap);
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	va_end(ap);
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}
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static const char *quote_crnl(const char *path)
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{
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	static struct strbuf new_path = STRBUF_INIT;
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	if (!path)
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		return NULL;
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	strbuf_reset(&new_path);
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	while (*path) {
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		switch (*path) {
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		case '\\': strbuf_addstr(&new_path, "\\\\"); break;
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		case '\n': strbuf_addstr(&new_path, "\\n"); break;
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		case '\r': strbuf_addstr(&new_path, "\\r"); break;
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		default:
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			strbuf_addch(&new_path, *path);
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		}
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		path++;
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	}
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	return new_path.buf;
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}
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void trace_repo_setup(void)
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{
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	const char *git_work_tree, *prefix = startup_info->prefix;
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	char *cwd;
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	if (!trace_want(&trace_setup_key))
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		return;
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	cwd = xgetcwd();
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	if (!(git_work_tree = get_git_work_tree()))
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		git_work_tree = "(null)";
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	if (!startup_info->prefix)
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		prefix = "(null)";
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	trace_printf_key(&trace_setup_key, "setup: git_dir: %s\n", quote_crnl(get_git_dir()));
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	trace_printf_key(&trace_setup_key, "setup: git_common_dir: %s\n", quote_crnl(get_git_common_dir()));
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	trace_printf_key(&trace_setup_key, "setup: worktree: %s\n", quote_crnl(git_work_tree));
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	trace_printf_key(&trace_setup_key, "setup: cwd: %s\n", quote_crnl(cwd));
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	trace_printf_key(&trace_setup_key, "setup: prefix: %s\n", quote_crnl(prefix));
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	free(cwd);
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}
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int trace_want(struct trace_key *key)
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{
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	return !!get_trace_fd(key, NULL);
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}
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#if defined(HAVE_CLOCK_GETTIME) && defined(HAVE_CLOCK_MONOTONIC)
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static inline uint64_t highres_nanos(void)
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{
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	struct timespec ts;
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	if (clock_gettime(CLOCK_MONOTONIC, &ts))
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		return 0;
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	return (uint64_t) ts.tv_sec * 1000000000 + ts.tv_nsec;
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}
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#elif defined (GIT_WINDOWS_NATIVE)
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static inline uint64_t highres_nanos(void)
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{
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	static uint64_t high_ns, scaled_low_ns;
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	static int scale;
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	LARGE_INTEGER cnt;
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	if (!scale) {
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		if (!QueryPerformanceFrequency(&cnt))
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			return 0;
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		/* high_ns = number of ns per cnt.HighPart */
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		high_ns = (1000000000LL << 32) / (uint64_t) cnt.QuadPart;
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		/*
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		 * Number of ns per cnt.LowPart is 10^9 / frequency (or
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		 * high_ns >> 32). For maximum precision, we scale this factor
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		 * so that it just fits within 32 bit (i.e. won't overflow if
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		 * multiplied with cnt.LowPart).
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		 */
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		scaled_low_ns = high_ns;
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		scale = 32;
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		while (scaled_low_ns >= 0x100000000LL) {
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			scaled_low_ns >>= 1;
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			scale--;
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		}
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	}
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	/* if QPF worked on initialization, we expect QPC to work as well */
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	QueryPerformanceCounter(&cnt);
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	return (high_ns * cnt.HighPart) +
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	       ((scaled_low_ns * cnt.LowPart) >> scale);
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}
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#else
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# define highres_nanos() 0
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#endif
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static inline uint64_t gettimeofday_nanos(void)
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{
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	struct timeval tv;
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	gettimeofday(&tv, NULL);
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	return (uint64_t) tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
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}
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/*
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 * Returns nanoseconds since the epoch (01/01/1970), for performance tracing
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 * (i.e. favoring high precision over wall clock time accuracy).
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 */
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uint64_t getnanotime(void)
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{
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	static uint64_t offset;
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	if (offset > 1) {
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		/* initialization succeeded, return offset + high res time */
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		return offset + highres_nanos();
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	} else if (offset == 1) {
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		/* initialization failed, fall back to gettimeofday */
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		return gettimeofday_nanos();
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	} else {
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		/* initialize offset if high resolution timer works */
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		uint64_t now = gettimeofday_nanos();
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		uint64_t highres = highres_nanos();
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		if (highres)
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			offset = now - highres;
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		else
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			offset = 1;
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		return now;
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	}
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}
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static struct strbuf command_line = STRBUF_INIT;
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static void print_command_performance_atexit(void)
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{
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	trace_performance_leave("git command:%s", command_line.buf);
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}
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void trace_command_performance(const char **argv)
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{
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	if (!trace_want(&trace_perf_key))
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		return;
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	if (!command_line.len)
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		atexit(print_command_performance_atexit);
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	strbuf_reset(&command_line);
426
	sq_quote_argv_pretty(&command_line, argv);
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	trace_performance_enter();
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}
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