[PATCH v7 03/10] pkt-line: add packet_write_fmt_gently()

[larsxschneider]

From: Lars Schneider <larsxschnei...@gmail.com>

packet_write_fmt() would die in case of a write error even though for
some callers an error would be acceptable. Add packet_write_fmt_gently()
which writes a formatted pkt-line and returns `0` for success and `-1`
for an error.

Signed-off-by: Lars Schneider <larsxschnei...@gmail.com>
---
 pkt-line.c | 43 +++++++++++++++++++++++++++++++++++++++----
 pkt-line.h |  1 +
 2 files changed, 40 insertions(+), 4 deletions(-)

diff --git a/pkt-line.c b/pkt-line.c
index e8adc0f..3824d05 100644
--- a/pkt-line.c
+++ b/pkt-line.c
@@ -125,16 +125,51 @@ static void format_packet(struct strbuf *out, const char 
*fmt, va_list args)
        packet_trace(out->buf + orig_len + 4, n - 4, 1);
 }
 
+static int packet_write_fmt_1(int fd, int gently,
+                              const char *fmt, va_list args)
+{
+       struct strbuf buf = STRBUF_INIT;
+       size_t count;
+
+       format_packet(&buf, fmt, args);
+       count = write_in_full(fd, buf.buf, buf.len);
+       if (count == buf.len)
+               return 0;
+
+       if (!gently) {
+               if (errno == EPIPE) {
+                       if (in_async())
+                               async_exit(141);
+
+                       signal(SIGPIPE, SIG_DFL);
+                       raise(SIGPIPE);
+                       /* Should never happen, but just in case... */
+                       exit(141);
+               }
+               die_errno("packet write error");
+       }
+       error("packet write failed");
+       return -1;
+}
+
 void packet_write_fmt(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);
+       packet_write_fmt_1(fd, 0, fmt, args);
+       va_end(args);
+}
+
+int packet_write_fmt_gently(int fd, const char *fmt, ...)
+{
+       int status;
+       va_list args;
+
+       va_start(args, fmt);
+       status = packet_write_fmt_1(fd, 1, fmt, args);
        va_end(args);
-       write_or_die(fd, buf.buf, buf.len);
+       return status;
 }
 
 void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
diff --git a/pkt-line.h b/pkt-line.h
index 1902fb3..3caea77 100644
--- a/pkt-line.h
+++ b/pkt-line.h
@@ -23,6 +23,7 @@ void packet_flush(int fd);
 void packet_write_fmt(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)));
+int packet_write_fmt_gently(int fd, const char *fmt, ...) 
__attribute__((format (printf, 2, 3)));
 
 /*
  * Read a packetized line into the buffer, which must be at least size bytes
-- 
2.10.0