[PATCH v5 04/15] pkt-line: add packet_write_gently()

[larsxschneider@gmail.com]

From: Lars Schneider <larsxschneider@gmail.com>

packet_write() 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.

Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
---
 pkt-line.c | 12 ++++++++++++
 pkt-line.h |  1 +
 2 files changed, 13 insertions(+)

diff --git a/pkt-line.c b/pkt-line.c
index e6b8410..4f25748 100644
--- a/pkt-line.c
+++ b/pkt-line.c
@@ -3,6 +3,7 @@
 #include "run-command.h"
 
 char packet_buffer[LARGE_PACKET_MAX];
+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);
@@ -141,6 +142,17 @@ void packet_write(int fd, const char *fmt, ...)
 	write_or_die(fd, buf.buf, buf.len);
 }
 
+int packet_write_gently(const int fd_out, const char *buf, size_t size)
+{
+	if (size > PKTLINE_DATA_MAXLEN)
+		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;
diff --git a/pkt-line.h b/pkt-line.h
index 3cb9d91..88584f1 100644
--- a/pkt-line.h
+++ b/pkt-line.h
@@ -77,6 +77,7 @@ char *packet_read_line_buf(char **src_buf, size_t *src_len, int *size);
 
 #define DEFAULT_PACKET_MAX 1000
 #define LARGE_PACKET_MAX 65520
+#define PKTLINE_DATA_MAXLEN (LARGE_PACKET_MAX - 4)
 extern char packet_buffer[LARGE_PACKET_MAX];
 
 #endif
-- 
2.9.2