[PATCH v10 03/20] pkt-line: add gentle version of packet_write

[David Turner <dturner@twopensource.com>]

packet_write calls write_or_die, which dies with a sigpipe even if
calling code has explicitly blocked that signal.

Add packet_write_gently and packet_flush_gently, which don't.  Soon,
we will use this for communication with git index-helper, which, being
merely an optimization, should be permitted to die without disrupting
clients.

Signed-off-by: David Turner <dturner@twopensource.com>
---
 pkt-line.c | 18 ++++++++++++++++++
 pkt-line.h |  2 ++
 2 files changed, 20 insertions(+)

diff --git a/pkt-line.c b/pkt-line.c
index 62fdb37..f964446 100644
--- a/pkt-line.c
+++ b/pkt-line.c
@@ -91,6 +91,12 @@ void packet_flush(int fd)
 	write_or_die(fd, "0000", 4);
 }
 
+int packet_flush_gently(int fd)
+{
+	packet_trace("0000", 4, 1);
+	return write_in_full(fd, "0000", 4) != 4;
+}
+
 void packet_buf_flush(struct strbuf *buf)
 {
 	packet_trace("0000", 4, 1);
@@ -130,6 +136,18 @@ void packet_write(int fd, const char *fmt, ...)
 	write_or_die(fd, buf.buf, buf.len);
 }
 
+int packet_write_gently(int fd, const char *fmt, ...)
+{
+	static struct strbuf buf = STRBUF_INIT;
+	va_list args;
+
+	strbuf_reset(&buf);
+	va_start(args, fmt);
+	format_packet(&buf, fmt, args);
+	va_end(args);
+	return write_in_full(fd, buf.buf, buf.len) != buf.len;
+}
+
 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..deffcb5 100644
--- a/pkt-line.h
+++ b/pkt-line.h
@@ -20,7 +20,9 @@
  * side can't, we stay with pure read/write interfaces.
  */
 void packet_flush(int fd);
+int packet_flush_gently(int fd);
 void packet_write(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
+int packet_write_gently(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
 void packet_buf_flush(struct strbuf *buf);
 void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
 
-- 
2.4.2.767.g62658d5-twtrsrc