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| | # Copyright (C) 2019 all contributors <meta@public-inbox.org>
# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
# RFC 8054 NNTP COMPRESS DEFLATE implementation
#
# RSS usage for 10K idle-but-did-something NNTP clients on 64-bit:
# TLS + DEFLATE[a] : 1.8 GB (MemLevel=9, 1.2 GB with MemLevel=8)
# TLS + DEFLATE[b] : ~300MB
# TLS only : <200MB
# plain : <50MB
#
# [a] - initial implementation using per-client Deflate contexts and buffer
#
# [b] - memory-optimized implementation using a global deflate context.
# It's less efficient in terms of compression, but way more
# efficient in terms of server memory usage.
package PublicInbox::NNTPdeflate;
use strict;
use warnings;
use 5.010_001;
use base qw(PublicInbox::NNTP);
use Compress::Raw::Zlib;
use Hash::Util qw(unlock_hash); # dependency of fields for perl 5.10+, anyways
my %IN_OPT = (
-Bufsize => PublicInbox::NNTP::LINE_MAX,
-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, $self) = @_;
my ($in, $err) = Compress::Raw::Zlib::Inflate->new(%IN_OPT);
if ($err != Z_OK) {
$self->err("Inflate->new failed: $err");
$self->res('403 Unable to activate compression');
return;
}
unlock_hash(%$self);
$self->res('206 Compression active');
bless $self, $class;
$self->{zin} = [ $in, '' ];
}
# overrides PublicInbox::NNTP::compressed
sub compressed { 1 }
# SUPER is PublicInbox::DS::do_read, so $_[1] may be a reference or not
sub do_read ($$$$) {
my ($self, $rbuf, $len, $off) = @_;
my $zin = $self->{zin} or return; # closed
my $deflated = \($zin->[1]);
my $r = $self->SUPER::do_read($deflated, $len) or return;
# assert(length($$rbuf) == $off) as far as NNTP.pm is concerned
# -ConsumeInput is true, so $deflated is automatically emptied
my $err = $zin->[0]->inflate($deflated, $rbuf);
if ($err == Z_OK) {
$r = length($$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;
|