Avoid errors and warnings when attempting to do I/O on zero bytes

Unfortunately, while {read,write}_in_full do take into account
zero-sized reads/writes; their die and whine variants do not.

I have a repository where there are zero-sized files in
the history that was triggering these things.

Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/sha1_file.c b/sha1_file.c
index 53e25f278c6193860431f63a3c9de97f4e347f27..18dd89b50a23a4a99b51d8e99d0c67cace2a1a2d 100644 (file)
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -1620,6 +1620,8 @@ static int write_buffer(int fd, const void *buf, size_t len)
 {
        ssize_t size;
 
+       if (!len)
+               return 0;
        size = write_in_full(fd, buf, len);
        if (!size)
                return error("file write: disk full");

diff --git a/write_or_die.c b/write_or_die.c
index 7f99a22aed43afd8ca06d3eafef8d3e836b15107..488de721da8a316c06bf53e9091633e5ac415390 100644 (file)
--- a/write_or_die.c
+++ b/write_or_die.c
@@ -26,6 +26,8 @@ void read_or_die(int fd, void *buf, size_t count)
 {
        ssize_t loaded;
 
+       if (!count)
+               return;
        loaded = read_in_full(fd, buf, count);
        if (loaded == 0)
                die("unexpected end of file");
@@ -58,6 +60,8 @@ void write_or_die(int fd, const void *buf, size_t count)
 {
        ssize_t written;
 
+       if (!count)
+               return;
        written = write_in_full(fd, buf, count);
        if (written == 0)
                die("disk full?");
@@ -72,6 +76,8 @@ int write_or_whine_pipe(int fd, const void *buf, size_t count, const char *msg)
 {
        ssize_t written;
 
+       if (!count)
+               return 1;
        written = write_in_full(fd, buf, count);
        if (written == 0) {
                fprintf(stderr, "%s: disk full?\n", msg);
@@ -92,6 +98,8 @@ int write_or_whine(int fd, const void *buf, size_t count, const char *msg)
 {
        ssize_t written;
 
+       if (!count)
+               return 1;
        written = write_in_full(fd, buf, count);
        if (written == 0) {
                fprintf(stderr, "%s: disk full?\n", msg);