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, 25 insertions, 73 deletions

diff --git a/lib/PublicInbox/WwwAtomStream.pm b/lib/PublicInbox/WwwAtomStream.pm
index 58330922..073df1df 100644
--- a/lib/PublicInbox/WwwAtomStream.pm
+++ b/lib/PublicInbox/WwwAtomStream.pm
@@ -7,107 +7,59 @@
 # more common "push" model)
 package PublicInbox::WwwAtomStream;
 use strict;
-use warnings;
+use parent 'PublicInbox::GzipFilter';
 
 use POSIX qw(strftime);
 use Digest::SHA qw(sha1_hex);
 use PublicInbox::Address;
 use PublicInbox::Hval qw(ascii_html mid_href);
 use PublicInbox::MsgTime qw(msg_timestamp);
-use PublicInbox::GzipFilter qw(gzf_maybe);
-use PublicInbox::GitAsyncCat;
-
-# called by generic PSGI server after getline,
-# and also by PublicInbox::HTTP::close
-sub close { !!delete($_[0]->{http_out}) }
 
 sub new {
         my ($class, $ctx, $cb) = @_;
         $ctx->{feed_base_url} = $ctx->{-inbox}->base_url($ctx->{env});
-        $ctx->{cb} = $cb || \&close;
+        $ctx->{cb} = $cb || \&PublicInbox::GzipFilter::close;
         $ctx->{emit_header} = 1;
         bless $ctx, $class;
 }
 
-# called by PublicInbox::DS::write
-sub atom_async_next {
+sub async_next ($) {
         my ($http) = @_; # PublicInbox::HTTP
-        atom_async_step($http->{forward});
-}
-
-# this is public-inbox-httpd-specific
-sub atom_blob_cb { # git->cat_async callback
-        my ($bref, $oid, $type, $size, $ctx) = @_;
-        my $http = $ctx->{env}->{'psgix.io'} or return; # client abort
-        my $smsg = delete $ctx->{smsg} or die 'BUG: no smsg';
-        if (!defined($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(\&atom_async_next);
-        } else {
-                $smsg->{blob} eq $oid or die "BUG: $smsg->{blob} != $oid";
-        }
-        my $buf = feed_entry($ctx, $smsg, PublicInbox::Eml->new($bref));
-        if (my $gzf = $ctx->{gzf}) {
-                $buf = $gzf->translate($buf);
-        }
-        # PublicInbox::HTTP::{Chunked,Identity}::write
-        $ctx->{http_out}->write($buf);
-
-        $http->next_step(\&atom_async_next);
+        my $ctx = $http->{forward} or return;
+        eval {
+                if (my $smsg = $ctx->{smsg} = $ctx->{cb}->($ctx)) {
+                        $ctx->smsg_blob($smsg);
+                } else {
+                        $ctx->{http_out}->write($ctx->translate('</feed>'));
+                        $ctx->close;
+                }
+        };
+        warn "E: $@" if $@;
 }
 
-sub atom_async_step { # this is public-inbox-httpd-specific
-        my ($ctx) = @_;
-        if (my $smsg = $ctx->{smsg} = $ctx->{cb}->($ctx)) {
-                git_async_cat($ctx->{-inbox}->git, $smsg->{blob},
-                                \&atom_blob_cb, $ctx);
-        } elsif (my $out = delete $ctx->{http_out}) {
-                if (my $gzf = delete $ctx->{gzf}) {
-                        $out->write($gzf->zflush);
-                }
-                $out->close;
-        }
+sub async_eml { # ->{async_eml} for async_blob_cb
+        my ($ctx, $eml) = @_;
+        my $smsg = delete $ctx->{smsg};
+        $ctx->{http_out}->write($ctx->translate(feed_entry($ctx, $smsg, $eml)))
 }
 
 sub response {
         my ($class, $ctx, $code, $cb) = @_;
         my $res_hdr = [ 'Content-Type' => 'application/atom+xml' ];
         $class->new($ctx, $cb);
-        $ctx->{gzf} = gzf_maybe($res_hdr, $ctx->{env});
-        if ($ctx->{env}->{'pi-httpd.async'}) {
-                sub {
-                        my ($wcb) = @_; # -httpd provided write callback
-                        $ctx->{http_out} = $wcb->([200, $res_hdr]);
-                        $ctx->{env}->{'psgix.io'}->{forward} = $ctx;
-                        atom_async_step($ctx); # start stepping
-                };
-        } else {
-                [ $code, $res_hdr, $ctx ];
-        }
+        $ctx->psgi_response($code, $res_hdr, \&async_next, \&async_eml);
 }
 
 # called once for each message by PSGI server
 sub getline {
         my ($self) = @_;
-        my $buf = do {
-                if (my $middle = $self->{cb}) {
-                        if (my $smsg = $middle->($self)) {
-                                my $eml = $self->{-inbox}->smsg_eml($smsg) or
-                                                return '';
-                                feed_entry($self, $smsg, $eml);
-                        } else {
-                                undef;
-                        }
-                }
-        } // (delete($self->{cb}) ? '</feed>' : undef);
-
-        # gzf may be GzipFilter, `undef' or `0'
-        my $gzf = $self->{gzf} or return $buf;
-
-        return $gzf->translate($buf) if defined $buf;
-        $self->{gzf} = 0; # next call to ->getline returns $buf (== undef)
-        $gzf->translate(undef);
+        my $cb = $self->{cb} or return;
+        while (my $smsg = $cb->($self)) {
+                my $eml = $self->{-inbox}->smsg_eml($smsg) or next;
+                return $self->translate(feed_entry($self, $smsg, $eml));
+        }
+        delete $self->{cb};
+        $self->zflush('</feed>');
 }
 
 # private