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| | # Copyright (C) 2020 all contributors <meta@public-inbox.org>
# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
# Qspawn filter
package PublicInbox::GzipFilter;
use strict;
use parent qw(Exporter);
use Compress::Raw::Zlib qw(Z_FINISH Z_OK);
our @EXPORT_OK = qw(gzf_maybe);
my %OPT = (-WindowBits => 15 + 16, -AppendOutput => 1);
my @GZIP_HDRS = qw(Vary Accept-Encoding Content-Encoding gzip);
sub new { bless {}, shift }
# for Qspawn if using $env->{'pi-httpd.async'}
sub attach {
my ($self, $fh) = @_;
$self->{fh} = $fh;
$self
}
# returns `0' and not `undef' on failure (see Www*Stream)
sub gzf_maybe ($$) {
my ($res_hdr, $env) = @_;
return 0 if (($env->{HTTP_ACCEPT_ENCODING}) // '') !~ /\bgzip\b/;
my ($gz, $err) = Compress::Raw::Zlib::Deflate->new(%OPT);
return 0 if $err != Z_OK;
# in case Plack::Middleware::Deflater is loaded:
$env->{'plack.skip-deflater'} = 1;
push @$res_hdr, @GZIP_HDRS;
bless { gz => $gz }, __PACKAGE__;
}
sub gzip_or_die () {
my ($gz, $err) = Compress::Raw::Zlib::Deflate->new(%OPT);
$err == Z_OK or die "Deflate->new failed: $err";
$gz;
}
# for GetlineBody (via Qspawn) when NOT using $env->{'pi-httpd.async'}
# Also used for ->getline callbacks
sub translate ($$) {
my $self = $_[0]; # $_[1] => input
# allocate the zlib context lazily here, instead of in ->new.
# Deflate contexts are memory-intensive and this object may
# be sitting in the Qspawn limiter queue for a while.
my $gz = $self->{gz} //= gzip_or_die();
my $zbuf = delete($self->{zbuf});
if (defined $_[1]) { # my $buf = $_[1];
my $err = $gz->deflate($_[1], $zbuf);
die "gzip->deflate: $err" if $err != Z_OK;
return $zbuf if length($zbuf) >= 8192;
$self->{zbuf} = $zbuf;
'';
} else { # undef == EOF
my $err = $gz->flush($zbuf, Z_FINISH);
die "gzip->flush: $err" if $err != Z_OK;
$zbuf;
}
}
sub write {
# my $ret = bytes::length($_[1]); # XXX does anybody care?
$_[0]->{fh}->write(translate($_[0], $_[1]));
}
# similar to ->translate; use this when we're sure we know we have
# more data to buffer after this
sub zmore {
my $self = $_[0]; # $_[1] => input
my $err = $self->{gz}->deflate($_[1], $self->{zbuf});
die "gzip->deflate: $err" if $err != Z_OK;
undef;
}
# flushes and returns the final bit of gzipped data
sub zflush ($;$) {
my $self = $_[0]; # $_[1] => final input (optional)
my $zbuf = delete $self->{zbuf};
my $gz = delete $self->{gz};
my $err;
if (defined $_[1]) {
$err = $gz->deflate($_[1], $zbuf);
die "gzip->deflate: $err" if $err != Z_OK;
}
$err = $gz->flush($zbuf, Z_FINISH);
die "gzip->flush: $err" if $err != Z_OK;
$zbuf;
}
sub close {
my ($self) = @_;
my $fh = delete $self->{fh};
$fh->write(zflush($self));
$fh->close;
}
1;
|