git-svn: do our best to ensure that our ref and rev_db are consistent

Defer any signals that cause termination while they are
updating; and put the update-ref call as close to the rename()
as possible.  Also, make things extra-safe (but slower) for
people using --no-metadata since they can't rely on .rev_db
being rebuilt if it's clobbered (well, I'm calling update-ref
with the -m flag for reflogs, we don't yet have a way to rebuild
.rev_db from reflogs.

Signed-off-by: Eric Wong <normalperson@yhbt.net>
This commit is contained in:
Eric Wong 2007-01-31 13:54:23 -08:00
parent ecc712ddc4
commit 373274f978

View File

@ -631,6 +631,7 @@ use vars qw/$default_repo_id $default_ref_id $_no_metadata $_follow_parent
$_repack $_repack_flags/;
use Carp qw/croak/;
use File::Path qw/mkpath/;
use File::Copy qw/copy/;
use IPC::Open3;
my $_repack_nr;
@ -645,6 +646,9 @@ BEGIN {
svn:entry:committed-date/;
}
my %LOCKFILES;
END { unlink keys %LOCKFILES if %LOCKFILES }
sub fetch_all {
my ($repo_id, $url, $fetch) = @_;
my @gs;
@ -1030,8 +1034,7 @@ sub do_git_commit {
die "Failed to commit, invalid sha1: $commit\n";
}
command_noisy('update-ref',$self->refname, $commit);
$self->rev_db_set($log_entry->{revision}, $commit);
$self->rev_db_set($log_entry->{revision}, $commit, 1);
$self->{last_rev} = $log_entry->{revision};
$self->{last_commit} = $commit;
@ -1353,11 +1356,28 @@ sub rebuild {
# to a revision: (41 * rev) is the byte offset.
# A record of 40 0s denotes an empty revision.
# And yes, it's still pretty fast (faster than Tie::File).
# These files are disposable unless --no-metadata is set
sub rev_db_set {
my ($self, $rev, $commit) = @_;
my ($self, $rev, $commit, $update_ref) = @_;
length $commit == 40 or croak "arg3 must be a full SHA1 hexsum\n";
open my $fh, '+<', $self->{db_path} or croak $!;
my ($db, $db_lock) = ($self->{db_path}, "$self->{db_path}.lock");
my $sig;
if ($update_ref) {
$SIG{INT} = $SIG{HUP} = $SIG{TERM} = $SIG{ALRM} = $SIG{PIPE} =
$SIG{USR1} = $SIG{USR2} = sub { $sig = $_[0] };
}
$LOCKFILES{$db_lock} = 1;
if ($_no_metadata) {
copy($db, $db_lock) or die "rev_db_set(@_): ",
"Failed to copy: ",
"$db => $db_lock ($!)\n";
} else {
rename $db, $db_lock or die "rev_db_set(@_): ",
"Failed to rename: ",
"$db => $db_lock ($!)\n";
}
open my $fh, '+<', $db_lock or croak $!;
my $offset = $rev * 41;
# assume that append is the common case:
seek $fh, 0, 2 or croak $!;
@ -1370,6 +1390,18 @@ sub rev_db_set {
seek $fh, $offset, 0 or croak $!;
print $fh $commit,"\n" or croak $!;
close $fh or croak $!;
if ($update_ref) {
command_noisy('update-ref', '-m', "r$rev",
$self->refname, $commit);
}
rename $db_lock, $db or die "rev_db_set(@_): ", "Failed to rename: ",
"$db_lock => $db ($!)\n";
delete $LOCKFILES{$db_lock};
if ($update_ref) {
$SIG{INT} = $SIG{HUP} = $SIG{TERM} = $SIG{ALRM} = $SIG{PIPE} =
$SIG{USR1} = $SIG{USR2} = 'DEFAULT';
kill $sig, $$ if defined $sig;
}
}
sub rev_db_get {