git/write-or-die.c
Chandra Pratap 556e68032f write-or-die: make GIT_FLUSH a Boolean environment variable
Among Git's environment variables, the ones marked as "Boolean"
accept values in a way similar to Boolean configuration variables,
i.e. values like 'yes', 'on', 'true' and positive numbers are
taken as "on" and values like 'no', 'off', 'false' are taken as
"off".

GIT_FLUSH can be used to force Git to use non-buffered I/O when
writing to stdout. It can only accept two values, '1' which causes
Git to flush more often and '0' which makes all output buffered.
Make GIT_FLUSH accept more values besides '0' and '1' by turning it
into a Boolean environment variable, modifying the required logic.
Update the related documentation.

Signed-off-by: Chandra Pratap <chandrapratap3519@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-01-04 10:32:21 -08:00

109 lines
2.3 KiB
C

#include "git-compat-util.h"
#include "parse.h"
#include "run-command.h"
#include "write-or-die.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;
if (f == stdout) {
if (skip_stdout_flush < 0) {
skip_stdout_flush = git_env_bool("GIT_FLUSH", -1);
if (skip_stdout_flush < 0) {
struct stat st;
if (fstat(fileno(stdout), &st))
skip_stdout_flush = 0;
else
skip_stdout_flush = S_ISREG(st.st_mode);
}
}
if (skip_stdout_flush && !ferror(f))
return;
}
if (fflush(f)) {
check_pipe(errno);
die_errno("write failure on '%s'", desc);
}
}
void fprintf_or_die(FILE *f, const char *fmt, ...)
{
va_list ap;
int ret;
va_start(ap, fmt);
ret = vfprintf(f, fmt, ap);
va_end(ap);
if (ret < 0) {
check_pipe(errno);
die_errno("write error");
}
}
static int maybe_fsync(int fd)
{
if (use_fsync < 0)
use_fsync = git_env_bool("GIT_TEST_FSYNC", 1);
if (!use_fsync)
return 0;
if (fsync_method == FSYNC_METHOD_WRITEOUT_ONLY &&
git_fsync(fd, FSYNC_WRITEOUT_ONLY) >= 0)
return 0;
return git_fsync(fd, FSYNC_HARDWARE_FLUSH);
}
void fsync_or_die(int fd, const char *msg)
{
if (maybe_fsync(fd) < 0)
die_errno("fsync error on '%s'", msg);
}
int fsync_component(enum fsync_component component, int fd)
{
if (fsync_components & component)
return maybe_fsync(fd);
return 0;
}
void fsync_component_or_die(enum fsync_component component, int fd, const char *msg)
{
if (fsync_components & component)
fsync_or_die(fd, msg);
}
void write_or_die(int fd, const void *buf, size_t count)
{
if (write_in_full(fd, buf, count) < 0) {
check_pipe(errno);
die_errno("write error");
}
}
void fwrite_or_die(FILE *f, const void *buf, size_t count)
{
if (fwrite(buf, 1, count, f) != count)
die_errno("fwrite error");
}
void fflush_or_die(FILE *f)
{
if (fflush(f))
die_errno("fflush error");
}