[1/2] pkt-line: add packet_fwrite

Commit Message

Jacob Vosmaer Aug. 26, 2021, 10:06 a.m. UTC

This adds a new function packet_fwrite which works like packet_write,
except it writes to a stdio stream.

Helped-by: Patrick Steinhardt <[e-mail]>
Signed-off-by: Jacob Vosmaer <[e-mail]>
---
 cache.h        |  1 +
 pkt-line.c     | 16 ++++++++++++++++
 pkt-line.h     |  1 +
 write-or-die.c |  6 ++++++
 4 files changed, 24 insertions(+)

Comments

Junio C Hamano Aug. 26, 2021, 4:33 p.m. UTC | #1

Jacob Vosmaer <[e-mail]> writes:

> This adds a new function packet_fwrite which works like packet_write,
> except it writes to a stdio stream.
>
> Helped-by: Patrick Steinhardt <[e-mail]>
> Signed-off-by: Jacob Vosmaer <[e-mail]>
> ---
>  cache.h        |  1 +
>  pkt-line.c     | 16 ++++++++++++++++
>  pkt-line.h     |  1 +
>  write-or-die.c |  6 ++++++
>  4 files changed, 24 insertions(+)


I wonder if our readers are all proficient enough not to require
some comment to warn them about the care that must be taken when
packet_fwrite() and packet_write() are mixed together (i.e. stdio
flushing, etc.), but other than that, this sounds quite
straight-forward.

Patch

diff --git a/cache.h b/cache.h
index bd4869beee..fbefe0927b 100644
--- a/cache.h
+++ b/cache.h
@@ -1736,6 +1736,7 @@  extern const char *git_mailmap_blob;
 void maybe_flush_or_die(FILE *, const char *);
 __attribute__((format (printf, 2, 3)))
 void fprintf_or_die(FILE *, const char *fmt, ...);
+void fwrite_or_die(FILE *f, const void *buf, size_t count);
 
 #define COPY_READ_ERROR (-2)
 #define COPY_WRITE_ERROR (-3)
diff --git a/pkt-line.c b/pkt-line.c
index 9f63eae2e6..244b326708 100644
--- a/pkt-line.c
+++ b/pkt-line.c
@@ -243,6 +243,22 @@  void packet_write(int fd_out, const char *buf, size_t size)
 		die("%s", err.buf);
 }
 
+void packet_fwrite(FILE *f, const char *buf, size_t size)
+{
+	size_t packet_size;
+	char header[4];
+
+	if (size > LARGE_PACKET_DATA_MAX)
+		die(_("packet write failed - data exceeds max packet size"));
+
+	packet_trace(buf, size, 1);
+	packet_size = size + 4;
+
+	set_packet_header(header, packet_size);
+	fwrite_or_die(f, header, 4);
+	fwrite_or_die(f, buf, size);
+}
+
 void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
 {
 	va_list args;
diff --git a/pkt-line.h b/pkt-line.h
index 5af5f45687..c9cb5e1719 100644
--- a/pkt-line.h
+++ b/pkt-line.h
@@ -28,6 +28,7 @@  void packet_buf_flush(struct strbuf *buf);
 void packet_buf_delim(struct strbuf *buf);
 void set_packet_header(char *buf, int size);
 void packet_write(int fd_out, const char *buf, size_t size);
+void packet_fwrite(FILE *f, const char *buf, size_t size);
 void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
 void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len);
 int packet_flush_gently(int fd);
diff --git a/write-or-die.c b/write-or-die.c
index d33e68f6ab..d82ef54f90 100644
--- a/write-or-die.c
+++ b/write-or-die.c
@@ -70,3 +70,9 @@  void write_or_die(int fd, const void *buf, size_t count)
 		die_errno("write error");
 	}
 }
+
+void fwrite_or_die(FILE *f, const void *buf, size_t count)
+{
+	if (fwrite(buf, count, 1, f) != 1)
+		die_errno("write error");
+}