1 # Copyright (C) all contributors <meta@public-inbox.org>
2 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
4 # RFC 8054 NNTP COMPRESS DEFLATE implementation
5 # RFC 4978 IMAP COMPRESS=DEFLATE extension
7 # RSS usage for 10K idle-but-did-something NNTP clients on 64-bit:
8 # TLS + DEFLATE[a] : 1.8 GB (MemLevel=9, 1.2 GB with MemLevel=8)
9 # TLS + DEFLATE[b] : ~300MB
13 # [a] - initial implementation using per-client Deflate contexts and buffer
15 # [b] - memory-optimized implementation using a global deflate context.
16 # It's less efficient in terms of compression, but way more
17 # efficient in terms of server memory usage.
18 package PublicInbox::DSdeflate;
21 use Compress::Raw::Zlib;
25 -WindowBits => -15, # RFC 1951
29 # global deflate context and buffer
33 $zbuf = \(my $initial = ''); # replaced by $next in dflush/write
34 ($zout, $err) = Compress::Raw::Zlib::Deflate->new(
35 # nnrpd (INN) and Compress::Raw::Zlib favor MemLevel=9,
36 # the zlib C library and git use MemLevel=8 as the default
38 -Bufsize => 65536, # same as nnrpd
39 -WindowBits => -15, # RFC 1951
42 $err == Z_OK or die "Failed to initialize zlib deflate stream: $err";
46 my ($class, $self) = @_;
47 my ($in, $err) = Compress::Raw::Zlib::Inflate->new(%IN_OPT);
49 warn("Inflate->new failed: $err\n");
56 # overrides PublicInbox::DS::compressed
60 my ($self, $rbuf, $len, $off) = @_;
62 my $zin = $self->{zin} or return; # closed
64 my $dbuf = delete($self->{dbuf}) // '';
65 $doff = length($dbuf);
66 my $r = PublicInbox::DS::do_read($self, \$dbuf, $len, $doff) or return;
68 # Workaround inflate bug appending to OOK scalars:
69 # <https://rt.cpan.org/Ticket/Display.html?id=132734>
70 # We only have $off if the client is pipelining, and pipelining
71 # is where our substr() OOK optimization in event_step makes sense.
78 # assert(length($$rbuf) == $off) as far as NNTP.pm is concerned
79 # -ConsumeInput is true, so $dbuf is automatically emptied
80 my $err = $zin->inflate($dbuf, $rbuf);
82 $self->{dbuf} = $dbuf if $dbuf ne '';
83 $r = length($$rbuf) and return $r;
84 # nothing ready, yet, get more, later
93 # override PublicInbox::DS::msg_more
97 # $_[1] may be a reference or not for ->deflate
98 my $err = $zout->deflate($_[1], $zbuf);
99 $err == Z_OK or die "->deflate failed $err";
106 my $deflated = $zbuf;
107 $zbuf = \(my $next = '');
109 my $err = $zout->flush($deflated, Z_FULL_FLUSH);
110 $err == Z_OK or die "->flush failed $err";
112 # We can still let the lower socket layer do buffering:
113 PublicInbox::DS::msg_more($self, $$deflated);
116 # compatible with PublicInbox::DS::write, so $_[1] may be a reference or not
119 return PublicInbox::DS::write($self, $_[1]) if ref($_[1]) eq 'CODE';
121 my $deflated = $zbuf;
122 $zbuf = \(my $next = '');
124 # $_[1] may be a reference or not for ->deflate
125 my $err = $zout->deflate($_[1], $deflated);
126 $err == Z_OK or die "->deflate failed $err";
127 $err = $zout->flush($deflated, Z_FULL_FLUSH);
128 $err == Z_OK or die "->flush failed $err";
130 # We can still let the socket layer do buffering:
131 PublicInbox::DS::write($self, $deflated);