mirror of
https://github.com/git/git.git
synced 2024-11-16 06:03:44 +01:00
06f59e9f5d
This patch arose from a discussion started by Jim Meyering's patch whose intention was to provide better diagnostics for failed writes. Linus proposed a better way to do things, which also had the added benefit that adding a fflush() to git-log-* operations and incremental git-blame operations could improve interactive respose time feel, at the cost of making things a bit slower when we aren't piping the output to a downstream program. This patch skips the fflush() calls when stdout is a regular file, or if the environment variable GIT_FLUSH is set to "0". This latter can speed up a command such as: GIT_FLUSH=0 strace -c -f -e write time git-rev-list HEAD | wc -l a tiny amount. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
112 lines
2.3 KiB
C
112 lines
2.3 KiB
C
#include "cache.h"
|
|
|
|
/*
|
|
* Some cases use stdio, but want to flush after the write
|
|
* to get error handling (and to get better interactive
|
|
* behaviour - not buffering excessively).
|
|
*
|
|
* Of course, if the flush happened within the write itself,
|
|
* we've already lost the error code, and cannot report it any
|
|
* more. So we just ignore that case instead (and hope we get
|
|
* the right error code on the flush).
|
|
*
|
|
* If the file handle is stdout, and stdout is a file, then skip the
|
|
* flush entirely since it's not needed.
|
|
*/
|
|
void maybe_flush_or_die(FILE *f, const char *desc)
|
|
{
|
|
static int skip_stdout_flush = -1;
|
|
struct stat st;
|
|
char *cp;
|
|
|
|
if (f == stdout) {
|
|
if (skip_stdout_flush < 0) {
|
|
cp = getenv("GIT_FLUSH");
|
|
if (cp)
|
|
skip_stdout_flush = (atoi(cp) == 0);
|
|
else if ((fstat(fileno(stdout), &st) == 0) &&
|
|
S_ISREG(st.st_mode))
|
|
skip_stdout_flush = 1;
|
|
else
|
|
skip_stdout_flush = 0;
|
|
}
|
|
if (skip_stdout_flush && !ferror(f))
|
|
return;
|
|
}
|
|
if (fflush(f)) {
|
|
if (errno == EPIPE)
|
|
exit(0);
|
|
die("write failure on %s: %s", desc, strerror(errno));
|
|
}
|
|
}
|
|
|
|
int read_in_full(int fd, void *buf, size_t count)
|
|
{
|
|
char *p = buf;
|
|
ssize_t total = 0;
|
|
|
|
while (count > 0) {
|
|
ssize_t loaded = xread(fd, p, count);
|
|
if (loaded <= 0)
|
|
return total ? total : loaded;
|
|
count -= loaded;
|
|
p += loaded;
|
|
total += loaded;
|
|
}
|
|
|
|
return total;
|
|
}
|
|
|
|
int write_in_full(int fd, const void *buf, size_t count)
|
|
{
|
|
const char *p = buf;
|
|
ssize_t total = 0;
|
|
|
|
while (count > 0) {
|
|
ssize_t written = xwrite(fd, p, count);
|
|
if (written < 0)
|
|
return -1;
|
|
if (!written) {
|
|
errno = ENOSPC;
|
|
return -1;
|
|
}
|
|
count -= written;
|
|
p += written;
|
|
total += written;
|
|
}
|
|
|
|
return total;
|
|
}
|
|
|
|
void write_or_die(int fd, const void *buf, size_t count)
|
|
{
|
|
if (write_in_full(fd, buf, count) < 0) {
|
|
if (errno == EPIPE)
|
|
exit(0);
|
|
die("write error (%s)", strerror(errno));
|
|
}
|
|
}
|
|
|
|
int write_or_whine_pipe(int fd, const void *buf, size_t count, const char *msg)
|
|
{
|
|
if (write_in_full(fd, buf, count) < 0) {
|
|
if (errno == EPIPE)
|
|
exit(0);
|
|
fprintf(stderr, "%s: write error (%s)\n",
|
|
msg, strerror(errno));
|
|
return 0;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
int write_or_whine(int fd, const void *buf, size_t count, const char *msg)
|
|
{
|
|
if (write_in_full(fd, buf, count) < 0) {
|
|
fprintf(stderr, "%s: write error (%s)\n",
|
|
msg, strerror(errno));
|
|
return 0;
|
|
}
|
|
|
|
return 1;
|
|
}
|