-# Copyright (C) 2020-2021 all contributors <meta@public-inbox.org>
-# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
-# TODO: reduce duplication from PublicInbox::NNTPdeflate
-
-# RFC 4978
-package PublicInbox::IMAPdeflate;
-use strict;
-use warnings;
-use 5.010_001;
-use base qw(PublicInbox::IMAP);
-use Compress::Raw::Zlib;
-
-my %IN_OPT = (
- -Bufsize => 1024,
- -WindowBits => -15, # RFC 1951
- -AppendOutput => 1,
-);
-
-# global deflate context and buffer
-my $zbuf = \(my $buf = '');
-my $zout;
-{
- my $err;
- ($zout, $err) = Compress::Raw::Zlib::Deflate->new(
- # nnrpd (INN) and Compress::Raw::Zlib favor MemLevel=9,
- # the zlib C library and git use MemLevel=8 as the default
- # -MemLevel => 9,
- -Bufsize => 65536, # same as nnrpd
- -WindowBits => -15, # RFC 1951
- -AppendOutput => 1,
- );
- $err == Z_OK or die "Failed to initialize zlib deflate stream: $err";
-}
-
-sub enable {
- my ($class, $self, $tag) = @_;
- my ($in, $err) = Compress::Raw::Zlib::Inflate->new(%IN_OPT);
- if ($err != Z_OK) {
- $self->err("Inflate->new failed: $err");
- $self->write(\"$tag BAD failed to activate compression\r\n");
- return;
- }
- $self->write(\"$tag OK DEFLATE active\r\n");
- bless $self, $class;
- $self->{zin} = $in;
-}
-
-# overrides PublicInbox::NNTP::compressed
-sub compressed { 1 }
-
-sub do_read ($$$$) {
- my ($self, $rbuf, $len, $off) = @_;
-
- my $zin = $self->{zin} or return; # closed
- my $doff;
- my $dbuf = delete($self->{dbuf}) // '';
- $doff = length($dbuf);
- my $r = PublicInbox::DS::do_read($self, \$dbuf, $len, $doff) or return;
-
- # Workaround inflate bug appending to OOK scalars:
- # <https://rt.cpan.org/Ticket/Display.html?id=132734>
- # We only have $off if the client is pipelining, and pipelining
- # is where our substr() OOK optimization in event_step makes sense.
- if ($off) {
- my $copy = $$rbuf;
- undef $$rbuf;
- $$rbuf = $copy;
- }
-
- # assert(length($$rbuf) == $off) as far as NNTP.pm is concerned
- # -ConsumeInput is true, so $dbuf is automatically emptied
- my $err = $zin->inflate($dbuf, $rbuf);
- if ($err == Z_OK) {
- $self->{dbuf} = $dbuf if $dbuf ne '';
- $r = length($$rbuf) and return $r;
- # nothing ready, yet, get more, later
- $self->requeue;
- } else {
- delete $self->{zin};
- $self->close;
- }
- 0;
-}
-
-# override PublicInbox::DS::msg_more
-sub msg_more ($$) {
- my $self = $_[0];
-
- # $_[1] may be a reference or not for ->deflate
- my $err = $zout->deflate($_[1], $zbuf);
- $err == Z_OK or die "->deflate failed $err";
- 1;
-}
-
-sub zflush ($) {
- my ($self) = @_;
-
- my $deflated = $zbuf;
- $zbuf = \(my $next = '');
-
- my $err = $zout->flush($deflated, Z_FULL_FLUSH);
- $err == Z_OK or die "->flush failed $err";
-
- # We can still let the lower socket layer do buffering:
- PublicInbox::DS::msg_more($self, $$deflated);
-}
-
-# compatible with PublicInbox::DS::write, so $_[1] may be a reference or not
-sub write ($$) {
- my $self = $_[0];
- return PublicInbox::DS::write($self, $_[1]) if ref($_[1]) eq 'CODE';
-
- my $deflated = $zbuf;
- $zbuf = \(my $next = '');
-
- # $_[1] may be a reference or not for ->deflate
- my $err = $zout->deflate($_[1], $deflated);
- $err == Z_OK or die "->deflate failed $err";
- $err = $zout->flush($deflated, Z_FULL_FLUSH);
- $err == Z_OK or die "->flush failed $err";
-
- # We can still let the socket layer do buffering:
- PublicInbox::DS::write($self, $deflated);
-}
-
-1;