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9540ce5030
We write each line of a new packed-refs file individually using a write() syscall (and sometimes 2, if the ref is peeled). Since each line is only about 50-100 bytes long, this creates a lot of system call overhead. We can instead open a stdio handle around our descriptor and use fprintf to write to it. The extra buffering is not a problem for us, because nobody will read our new packed-refs file until we call commit_lock_file (by which point we have flushed everything). On a pathological repository with 8.5 million refs, this dropped the time to run `git pack-refs` from 20s to 6s. Signed-off-by: Jeff King <peff@peff.net> Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
103 lines
2.1 KiB
C
103 lines
2.1 KiB
C
#include "cache.h"
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static void check_pipe(int err)
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{
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if (err == EPIPE) {
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signal(SIGPIPE, SIG_DFL);
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raise(SIGPIPE);
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/* Should never happen, but just in case... */
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exit(141);
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}
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}
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/*
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* Some cases use stdio, but want to flush after the write
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* to get error handling (and to get better interactive
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* behaviour - not buffering excessively).
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*
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* Of course, if the flush happened within the write itself,
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* we've already lost the error code, and cannot report it any
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* more. So we just ignore that case instead (and hope we get
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* the right error code on the flush).
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*
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* If the file handle is stdout, and stdout is a file, then skip the
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* flush entirely since it's not needed.
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*/
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void maybe_flush_or_die(FILE *f, const char *desc)
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{
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static int skip_stdout_flush = -1;
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struct stat st;
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char *cp;
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if (f == stdout) {
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if (skip_stdout_flush < 0) {
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cp = getenv("GIT_FLUSH");
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if (cp)
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skip_stdout_flush = (atoi(cp) == 0);
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else if ((fstat(fileno(stdout), &st) == 0) &&
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S_ISREG(st.st_mode))
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skip_stdout_flush = 1;
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else
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skip_stdout_flush = 0;
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}
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if (skip_stdout_flush && !ferror(f))
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return;
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}
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if (fflush(f)) {
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check_pipe(errno);
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die_errno("write failure on '%s'", desc);
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}
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}
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void fprintf_or_die(FILE *f, const char *fmt, ...)
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{
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va_list ap;
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int ret;
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va_start(ap, fmt);
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ret = vfprintf(f, fmt, ap);
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va_end(ap);
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if (ret < 0) {
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check_pipe(errno);
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die_errno("write error");
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}
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}
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void fsync_or_die(int fd, const char *msg)
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{
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if (fsync(fd) < 0) {
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die_errno("fsync error on '%s'", msg);
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}
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}
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void write_or_die(int fd, const void *buf, size_t count)
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{
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if (write_in_full(fd, buf, count) < 0) {
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check_pipe(errno);
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die_errno("write error");
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}
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}
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int write_or_whine_pipe(int fd, const void *buf, size_t count, const char *msg)
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{
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if (write_in_full(fd, buf, count) < 0) {
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check_pipe(errno);
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fprintf(stderr, "%s: write error (%s)\n",
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msg, strerror(errno));
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return 0;
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}
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return 1;
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}
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int write_or_whine(int fd, const void *buf, size_t count, const char *msg)
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{
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if (write_in_full(fd, buf, count) < 0) {
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fprintf(stderr, "%s: write error (%s)\n",
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msg, strerror(errno));
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return 0;
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}
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return 1;
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}
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