1 # Copyright (C) 2020 all contributors <meta@public-inbox.org>
2 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
3 # TODO: reduce duplication from PublicInbox::NNTPdeflate
6 package PublicInbox::IMAPdeflate;
10 use base qw(PublicInbox::IMAP);
11 use Compress::Raw::Zlib;
12 use Hash::Util qw(unlock_hash); # dependency of fields for perl 5.10+, anyways
16 -WindowBits => -15, # RFC 1951
20 # global deflate context and buffer
21 my $zbuf = \(my $buf = '');
25 ($zout, $err) = Compress::Raw::Zlib::Deflate->new(
26 # nnrpd (INN) and Compress::Raw::Zlib favor MemLevel=9,
27 # the zlib C library and git use MemLevel=8 as the default
29 -Bufsize => 65536, # same as nnrpd
30 -WindowBits => -15, # RFC 1951
33 $err == Z_OK or die "Failed to initialize zlib deflate stream: $err";
37 my ($class, $self, $tag) = @_;
38 my ($in, $err) = Compress::Raw::Zlib::Inflate->new(%IN_OPT);
40 $self->err("Inflate->new failed: $err");
41 $self->write(\"$tag BAD failed to activate compression\r\n");
45 $self->write(\"$tag OK DEFLATE active\r\n");
50 # overrides PublicInbox::NNTP::compressed
54 my ($self, $rbuf, $len, $off) = @_;
56 my $zin = $self->{zin} or return; # closed
58 my $dbuf = delete($self->{dbuf}) // '';
59 $doff = length($dbuf);
60 my $r = PublicInbox::DS::do_read($self, \$dbuf, $len, $doff) or return;
62 # Workaround inflate bug appending to OOK scalars:
63 # <https://rt.cpan.org/Ticket/Display.html?id=132734>
64 # We only have $off if the client is pipelining, and pipelining
65 # is where our substr() OOK optimization in event_step makes sense.
72 # assert(length($$rbuf) == $off) as far as NNTP.pm is concerned
73 # -ConsumeInput is true, so $dbuf is automatically emptied
74 my $err = $zin->inflate($dbuf, $rbuf);
76 $self->{dbuf} = $dbuf if $dbuf ne '';
77 $r = length($$rbuf) and return $r;
78 # nothing ready, yet, get more, later
87 # override PublicInbox::DS::msg_more
91 # $_[1] may be a reference or not for ->deflate
92 my $err = $zout->deflate($_[1], $zbuf);
93 $err == Z_OK or die "->deflate failed $err";
100 my $deflated = $zbuf;
101 $zbuf = \(my $next = '');
103 my $err = $zout->flush($deflated, Z_FULL_FLUSH);
104 $err == Z_OK or die "->flush failed $err";
106 # We can still let the lower socket layer do buffering:
107 PublicInbox::DS::msg_more($self, $$deflated);
110 # compatible with PublicInbox::DS::write, so $_[1] may be a reference or not
113 return PublicInbox::DS::write($self, $_[1]) if ref($_[1]) eq 'CODE';
115 my $deflated = $zbuf;
116 $zbuf = \(my $next = '');
118 # $_[1] may be a reference or not for ->deflate
119 my $err = $zout->deflate($_[1], $deflated);
120 $err == Z_OK or die "->deflate failed $err";
121 $err = $zout->flush($deflated, Z_FULL_FLUSH);
122 $err == Z_OK or die "->flush failed $err";
124 # We can still let the socket layer do buffering:
125 PublicInbox::DS::write($self, $deflated);