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| | # Copyright (C) all contributors <meta@public-inbox.org>
# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
# temporary stack for public-inbox-index
# FIXME: needs to support multi-hash in the same repo once git itself can
package PublicInbox::IdxStack;
use v5.12;
use Fcntl qw(:seek);
use constant PACK_FMT => eval { pack('Q', 1) } ? 'A1QQH*H*' : 'A1IIH*H*';
use autodie qw(open seek);
use PublicInbox::IO qw(read_all);
# start off in write-only mode
sub new {
open(my $io, '+>', undef);
# latest_cmt is still useful when the newest revision is a `d'(elete),
# otherwise we favor $sync->{latest_cmt} for checkpoints and {quit}
bless { wr => $io, latest_cmt => $_[1] }, __PACKAGE__
}
# file_char = [d|m]
sub push_rec {
my ($self, $file_char, $at, $ct, $blob_oid, $cmt_oid) = @_;
my $rec = pack(PACK_FMT, $file_char, $at, $ct, $blob_oid, $cmt_oid);
$self->{unpack_fmt} // do {
my $len = length($cmt_oid);
my $fmt = PACK_FMT;
$fmt =~ s/H\*/H$len/g;
$self->{rec_size} = length($rec);
$self->{unpack_fmt} = $fmt;
};
print { $self->{wr} } $rec;
$self->{tot_size} += length($rec);
}
sub num_records {
my ($self) = @_;
$self->{rec_size} ? $self->{tot_size} / $self->{rec_size} : 0;
}
# switch into read-only mode and returns self
sub read_prepare {
my ($self) = @_;
my $io = $self->{rd} = delete($self->{wr});
$io->flush or die "flush: $!";
$self;
}
sub pop_rec {
my ($self) = @_;
my $sz = $self->{rec_size} or return;
my $rec_pos = $self->{tot_size} -= $sz;
return if $rec_pos < 0;
seek($self->{rd}, $rec_pos, SEEK_SET);
unpack($self->{unpack_fmt}, read_all($self->{rd}, $sz));
}
1;
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