[PATCH v6 05/13] pkt-line: add packet_write_gently()

[larsxschneider@gmail.com]

From: Lars Schneider <larsxschneider@gmail.com>

packet_write_fmt() has two shortcomings. First, it uses format_packet()
which lets the caller only send string data via "%s". That means it
cannot be used for arbitrary data that may contain NULs. Second, it will
always die on error.

Add packet_write_gently() which writes arbitrary data and returns `0`
for success and `-1` for an error. This function is used by other
pkt-line functions in a subsequent patch.

Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
---
 pkt-line.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/pkt-line.c b/pkt-line.c
index cad26df..7e8a803 100644
--- a/pkt-line.c
+++ b/pkt-line.c
@@ -3,6 +3,7 @@
 #include "run-command.h"
 
 char packet_buffer[LARGE_PACKET_MAX];
+static char packet_write_buffer[LARGE_PACKET_MAX];
 static const char *packet_trace_prefix = "git";
 static struct trace_key trace_packet = TRACE_KEY_INIT(PACKET);
 static struct trace_key trace_pack = TRACE_KEY_INIT(PACKFILE);
@@ -155,6 +156,17 @@ int packet_write_fmt_gently(int fd, const char *fmt, ...)
 	return (write_in_full(fd, buf.buf, buf.len) == buf.len ? 0 : -1);
 }
 
+int packet_write_gently(const int fd_out, const char *buf, size_t size)
+{
+	if (size > sizeof(packet_write_buffer) - 4)
+		return -1;
+	packet_trace(buf, size, 1);
+	memmove(packet_write_buffer + 4, buf, size);
+	size += 4;
+	set_packet_header(packet_write_buffer, size);
+	return (write_in_full(fd_out, packet_write_buffer, size) == size ? 0 : -1);
+}
+
 void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
 {
 	va_list args;
-- 
2.9.2