1 files changed, 125 insertions, 0 deletions
diff --git a/trace.c b/trace.c
new file mode 100644
index 0000000000..90847c3fd8
--- /dev/null
+++ b/trace.c
@@ -0,0 +1,125 @@
+/*
+ * 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"
+
+/* Stolen from "imap-send.c". */
+static int git_vasprintf(char **strp, const char *fmt, va_list ap)
+{
+	int len;
+	char tmp[1024];
+
+	if ((len = vsnprintf(tmp, sizeof(tmp), fmt, ap)) < 0 ||
+	    !(*strp = xmalloc(len + 1)))
+		return -1;
+	if (len >= (int)sizeof(tmp))
+		vsprintf(*strp, fmt, ap);
+	else
+		memcpy(*strp, tmp, len + 1);
+	return len;
+}
+
+/* Stolen from "imap-send.c". */
+int nfvasprintf(char **str, const char *fmt, va_list va)
+{
+	int ret = git_vasprintf(str, fmt, va);
+	if (ret < 0)
+		die("Fatal: Out of memory\n");
+	return ret;
+}
+
+/* Get a trace file descriptor from GIT_TRACE env variable. */
+static int get_trace_fd()
+{
+	char *trace = getenv("GIT_TRACE");
+
+	if (!trace || !strcmp(trace, "0") || !strcasecmp(trace," false"))
+		return 0;
+	if (!strcmp(trace, "1") || !strcasecmp(trace, "true"))
+		return STDERR_FILENO;
+	if (strlen(trace) == 1 && isdigit(*trace))
+		return atoi(trace);
+
+	fprintf(stderr, "What does '%s' for GIT_TRACE means ?\n", trace);
+	fprintf(stderr, "Defaulting to tracing on stderr...\n");
+	return STDERR_FILENO;
+}
+
+static const char err_msg[] = "Could not trace into fd given by "
+	"GIT_TRACE environment variable";
+
+void trace_printf(const char *format, ...)
+{
+	char *trace_str;
+	va_list rest;
+	int fd = get_trace_fd();
+
+	if (!fd)
+		return;
+
+	va_start(rest, format);
+	nfvasprintf(&trace_str, format, rest);
+	va_end(rest);
+
+	write_or_whine(fd, trace_str, strlen(trace_str), err_msg);
+
+	free(trace_str);
+}
+
+void trace_argv_printf(const char **argv, int count, const char *format, ...)
+{
+	char *argv_str, *format_str, *trace_str;
+	size_t argv_len, format_len, trace_len;
+	va_list rest;
+	int fd = get_trace_fd();
+
+	if (!fd)
+		return;
+
+	/* Get the argv string. */
+	argv_str = sq_quote_argv(argv, count);
+	argv_len = strlen(argv_str);
+
+	/* Get the formated string. */
+	va_start(rest, format);
+	nfvasprintf(&format_str, format, rest);
+	va_end(rest);
+
+	/* Allocate buffer for trace string. */
+	format_len = strlen(format_str);
+	trace_len = argv_len + format_len + 1; /* + 1 for \n */
+	trace_str = xmalloc(trace_len + 1);
+
+	/* Copy everything into the trace string. */
+	strncpy(trace_str, format_str, format_len);
+	strncpy(trace_str + format_len, argv_str, argv_len);
+	strcpy(trace_str + trace_len - 1, "\n");
+
+	write_or_whine(fd, trace_str, trace_len, err_msg);
+
+	free(argv_str);
+	free(format_str);
+	free(trace_str);
+}