www: start making gzipfilter the parent response class

Virtually all of our responses are going to be gzipped, anyways.
This will allow us to utilize zlib as a buffering layer and
share common code for async blob retrieval responses.

To streamline this and allow GzipFilter to be a parent class,
we'll replace the NoopFilter with a similar CompressNoop class
which emulates the two Compress::Raw::Zlib::Deflate methods we
use.

This drops a bunch of redundant code and will hopefully make
upcoming WwwStream changes easier to reason about.

1 files changed, 13 insertions, 58 deletions

diff --git a/lib/PublicInbox/MboxGz.pm b/lib/PublicInbox/MboxGz.pm
index 716bf7b1..fdd16f68 100644
--- a/lib/PublicInbox/MboxGz.pm
+++ b/lib/PublicInbox/MboxGz.pm
@@ -6,77 +6,32 @@ use parent 'PublicInbox::GzipFilter';
 use PublicInbox::Eml;
 use PublicInbox::Hval qw/to_filename/;
 use PublicInbox::Mbox;
-use PublicInbox::GitAsyncCat;
 *msg_hdr = \&PublicInbox::Mbox::msg_hdr;
 *msg_body = \&PublicInbox::Mbox::msg_body;
 
-# this is public-inbox-httpd-specific
-sub mboxgz_blob_cb { # git->cat_async callback
-        my ($bref, $oid, $type, $size, $self) = @_;
-        my $http = $self->{env}->{'psgix.io'} or return; # client abort
-        my $smsg = delete $self->{smsg} or die 'BUG: no smsg';
-        if (!defined($oid)) {
-                # it's possible to have TOCTOU if an admin runs
-                # public-inbox-(edit|purge), just move onto the next message
-                return $http->next_step(\&mboxgz_async_next);
-        } else {
-                $smsg->{blob} eq $oid or die "BUG: $smsg->{blob} != $oid";
-        }
-        my $eml = PublicInbox::Eml->new($bref);
-        $self->zmore(msg_hdr($self, $eml, $smsg->{mid}));
-
-        # PublicInbox::HTTP::{Chunked,Identity}::write
-        $self->{http_out}->write($self->translate(msg_body($eml)));
-
-        $http->next_step(\&mboxgz_async_next);
-}
-
-# this is public-inbox-httpd-specific
-sub mboxgz_async_step ($) {
-        my ($self) = @_;
-        if (my $smsg = $self->{smsg} = $self->{cb}->($self)) {
-                git_async_cat($self->{-inbox}->git, $smsg->{blob},
-                                \&mboxgz_blob_cb, $self);
-        } elsif (my $out = delete $self->{http_out}) {
-                $out->write($self->zflush);
-                $out->close;
-        }
-}
-
-# called by PublicInbox::DS::write
-sub mboxgz_async_next {
+sub async_next ($) {
         my ($http) = @_; # PublicInbox::HTTP
-        mboxgz_async_step($http->{forward});
-}
-
-# called by PublicInbox::HTTP::close, or any other PSGI server
-sub close { !!delete($_[0]->{http_out}) }
-
-sub response {
-        my ($self, $cb, $res_hdr) = @_;
-        $self->{cb} = $cb;
-        bless $self, __PACKAGE__;
-        if ($self->{env}->{'pi-httpd.async'}) {
-                sub {
-                        my ($wcb) = @_; # -httpd provided write callback
-                        $self->{http_out} = $wcb->([200, $res_hdr]);
-                        $self->{env}->{'psgix.io'}->{forward} = $self;
-                        mboxgz_async_step($self); # start stepping
-                };
-        } else { # generic PSGI
-                [ 200, $res_hdr, $self ];
-        }
+        my $ctx = $http->{forward} or return;
+        eval {
+                $ctx->{smsg} = $ctx->{cb}->($ctx) or return $ctx->close;
+                $ctx->smsg_blob($ctx->{smsg});
+        };
+        warn "E: $@" if $@;
 }
 
 sub mbox_gz {
         my ($self, $cb, $fn) = @_;
+        $self->{cb} = $cb;
         $self->{base_url} = $self->{-inbox}->base_url($self->{env});
         $self->{gz} = PublicInbox::GzipFilter::gzip_or_die();
         $fn = to_filename($fn // 'no-subject');
         $fn = 'no-subject' if $fn eq '';
         # http://www.iana.org/assignments/media-types/application/gzip
-        response($self, $cb, [ qw(Content-Type application/gzip),
-                'Content-Disposition', "inline; filename=$fn.mbox.gz" ]);
+        bless $self, __PACKAGE__;
+        my $res_hdr = [ 'Content-Type' => 'application/gzip',
+                'Content-Disposition' => "inline; filename=$fn.mbox.gz" ];
+        $self->psgi_response(200, $res_hdr, \&async_next,
+                                \&PublicInbox::Mbox::async_eml);
 }
 
 # called by Plack::Util::foreach or similar (generic PSGI)