www: use PerlIO::scalar (zfh) for buffering

Calling Compress::Raw::Zlib::deflate is fairly expensive.
Relying on the `.=' (concat) operator inside ->zadd operator is
faster, but the method dispatch overhead is noticeable compared
to the original code where we had bare `.=' littered throughout.

Fortunately, `print' and `say' with the PerlIO::scalar IO layer
appears to offer better performance without high method dispatch
overhead.  This doesn't allow us to save as much memory as I
originally hoped, but does allow us to rely less on concat
operators in other places and just pass a list of args to
`print' and `say' as a appropriate.

This does reduce scratchpad use, however, allowing for large
memory savings, and we still ->deflate every single $eml.

1 files changed, 28 insertions, 30 deletions

diff --git a/lib/PublicInbox/View.pm b/lib/PublicInbox/View.pm
index 85dc3bd8..0753c06e 100644
--- a/lib/PublicInbox/View.pm
+++ b/lib/PublicInbox/View.pm
@@ -40,7 +40,7 @@ sub msg_page_i {
                                 "../${\mid_href($smsg->{mid})}/" : '';
                 if (_msg_page_prepare($eml, $ctx)) {
                         $eml->each_part(\&add_text_body, $ctx, 1);
-                        $ctx->zadd('</pre><hr>');
+                        print { $ctx->{zfh} } '</pre><hr>';
                 }
                 html_footer($ctx, $ctx->{first_hdr}) if !$ctx->{smsg};
                 ''; # XXX TODO cleanup
@@ -58,7 +58,7 @@ sub no_over_html ($) {
         PublicInbox::WwwStream::init($ctx);
         if (_msg_page_prepare($eml, $ctx)) { # sets {-title_html}
                 $eml->each_part(\&add_text_body, $ctx, 1);
-                $ctx->zadd('</pre><hr>');
+                print { $ctx->{zfh} } '</pre><hr>';
         }
         html_footer($ctx, $eml);
         $ctx->html_done;
@@ -240,12 +240,11 @@ sub eml_entry {
                 my $html = ascii_html($irt);
                 $rv .= qq(In-Reply-To: &lt;<a\nhref="$href">$html</a>&gt;\n)
         }
-        $rv .= "\n";
+        say { $ctx->zfh } $rv;
 
         # scan through all parts, looking for displayable text
         $ctx->{mhref} = $mhref;
         $ctx->{changed_href} = "#e$id"; # for diffstat "files? changed,"
-        $ctx->zadd($rv); # XXX $rv is small, reuse below
         $eml->each_part(\&add_text_body, $ctx, 1); # expensive
 
         # add the footer
@@ -386,8 +385,8 @@ sub pre_thread  { # walk_thread callback
 sub thread_eml_entry {
         my ($ctx, $eml) = @_;
         my ($beg, $end) = thread_adj_level($ctx, $ctx->{level});
-        $ctx->zadd($beg.'<pre>');
-        eml_entry($ctx, $eml) . '</pre>' . $end;
+        print { $ctx->zfh } $beg, '<pre>';
+        print { $ctx->{zfh} } eml_entry($ctx, $eml), '</pre>', $end;
 }
 
 sub next_in_queue ($$) {
@@ -414,15 +413,15 @@ sub stream_thread_i { # PublicInbox::WwwStream::getline callback
                                 if (!$ghost_ok) { # first non-ghost
                                         $ctx->{-title_html} =
                                                 ascii_html($smsg->{subject});
-                                        $ctx->zadd($ctx->html_top);
+                                        print { $ctx->zfh } $ctx->html_top;
                                 }
                                 return $smsg;
                         }
                         # buffer the ghost entry and loop
-                        $ctx->zadd(ghost_index_entry($ctx, $lvl, $smsg));
+                        print { $ctx->zfh } ghost_index_entry($ctx, $lvl, $smsg)
                 } else { # all done
-                        $ctx->zadd(join('', thread_adj_level($ctx, 0)));
-                        $ctx->zadd(${delete($ctx->{skel})});
+                        print { $ctx->zfh } thread_adj_level($ctx, 0),
+                                                ${delete($ctx->{skel})};
                         return;
                 }
         }
@@ -491,7 +490,7 @@ sub thread_html_i { # PublicInbox::WwwStream::getline callback
                 my $smsg = $ctx->{smsg};
                 if (exists $ctx->{-html_tip}) {
                         $ctx->{-title_html} = ascii_html($smsg->{subject});
-                        $ctx->zadd($ctx->html_top);
+                        print { $ctx->zfh } $ctx->html_top;
                 }
                 return eml_entry($ctx, $eml);
         } else {
@@ -499,7 +498,7 @@ sub thread_html_i { # PublicInbox::WwwStream::getline callback
                         return $smsg if exists($smsg->{blob});
                 }
                 my $skel = delete($ctx->{skel}) or return; # all done
-                $ctx->zadd($$skel);
+                print { $ctx->zfh } $$skel;
                 undef;
         }
 }
@@ -560,8 +559,9 @@ sub add_text_body { # callback for each_part
         my $ct = $part->content_type || 'text/plain';
         my $fn = $part->filename;
         my ($s, $err) = msg_part_text($part, $ct);
-        $s // return $ctx->zadd(attach_link($ctx, $ct, $p, $fn) // '');
-        my $buf = $part->{is_submsg} ? submsg_hdr($ctx, $part)."\n" : '';
+        my $zfh = $ctx->zfh;
+        $s // return print $zfh (attach_link($ctx, $ct, $p, $fn) // '');
+        say $zfh submsg_hdr($ctx, $part) if $part->{is_submsg};
 
         # makes no difference to browsers, and don't screw up filename
         # link generation in diffs with the extra '%0D'
@@ -609,21 +609,19 @@ sub add_text_body { # callback for each_part
         undef $s; # free memory
         if (defined($fn) || ($depth > 0 && !$part->{is_submsg}) || $err) {
                 # badly-encoded message with $err? tell the world about it!
-                $buf .= attach_link($ctx, $ct, $p, $fn, $err) . "\n";
+                say $zfh attach_link($ctx, $ct, $p, $fn, $err);
         }
         delete $part->{bdy}; # save memory
-        $ctx->zadd($buf);
-        undef $buf;
         for my $cur (@sections) { # $cur may be huge
                 if ($cur =~ /\A>/) {
                         # we use a <span> here to allow users to specify
                         # their own color for quoted text
-                        $ctx->zadd(qq(<span\nclass="q">),
-                                        $l->to_html($cur), '</span>');
+                        print $zfh qq(<span\nclass="q">),
+                                        $l->to_html($cur), '</span>';
                 } elsif ($diff) {
                         flush_diff($ctx, \$cur);
                 } else { # regular lines, OK
-                        $ctx->zadd($l->to_html($cur));
+                        print $zfh $l->to_html($cur);
                 }
                 undef $cur; # free memory
         }
@@ -685,10 +683,10 @@ sub _msg_page_prepare {
                 $hbuf .= qq[Message-ID: &lt;$x&gt; (<a href="raw">raw</a>)\n];
         }
         if (!$nr) { # first (and only) message, common case
-                $ctx->zadd($ctx->html_top, $hbuf);
+                print { $ctx->zfh } $ctx->html_top, $hbuf;
         } else {
                 delete $ctx->{-title_html};
-                $ctx->zadd($ctx->{-html_tip}, $hbuf);
+                print { $ctx->zfh } $ctx->{-html_tip}, $hbuf;
         }
         $ctx->{-linkify} //= PublicInbox::Linkify->new;
         $hbuf = '';
@@ -699,7 +697,7 @@ sub _msg_page_prepare {
                         $hbuf .= "$h: $_\n" for ($eml->header_raw($h));
                 }
                 $ctx->{-linkify}->linkify_mids('..', \$hbuf, 1); # escapes HTML
-                $ctx->zadd($hbuf);
+                print { $ctx->{zfh} } $hbuf;
                 $hbuf = '';
         }
         my @irt = $eml->header_raw('In-Reply-To');
@@ -717,7 +715,7 @@ sub _msg_page_prepare {
                 $hbuf .= 'References: <'.join(">\n\t<", @$refs).">\n" if @$refs;
         }
         $ctx->{-linkify}->linkify_mids('..', \$hbuf); # escapes HTML
-        $ctx->zadd($hbuf .= "\n");
+        say { $ctx->{zfh} } $hbuf;
         1;
 }
 
@@ -771,7 +769,7 @@ sub thread_skel ($$$) {
 sub html_footer {
         my ($ctx, $hdr) = @_;
         my $upfx = '../';
-        my ($related, $skel);
+        my (@related, $skel);
         my $foot = '<pre>';
         my $qry = delete $ctx->{-qry};
         if ($qry && $ctx->{ibx}->isrch) {
@@ -786,7 +784,7 @@ sub html_footer {
                 $q = wrap('', '', $q);
                 my $rows = ($q =~ tr/\n/\n/) + 1;
                 $q = ascii_html($q);
-                $related = <<EOM;
+                $related[0] = <<EOM;
 <form id=related
 action=$upfx
 ><pre>find likely ancestor, descendant, or conflicting patches for <a
@@ -799,7 +797,7 @@ EOM
         if ($ctx->{ibx}->over) {
                 my $t = ts2str($ctx->{-t_max});
                 my $t_fmt = fmt_ts($ctx->{-t_max});
-                my $fallback = $related ? "\t" : "<a id=related>\t</a>";
+                my $fallback = @related ? "\t" : "<a id=related>\t</a>";
                 $skel = <<EOF;
 ${fallback}other threads:[<a
 href="$upfx?t=$t">~$t_fmt UTC</a>|<a
@@ -834,10 +832,10 @@ EOF
         } else { # unindexed inboxes w/o over
                 $skel = qq( <a\nhref="$upfx">latest</a>);
         }
-        $foot .= qq(<a\nhref="#R">reply</a>);
         # $skel may be big for big threads, don't append it to $foot
-        $skel .= '</pre>' . ($related // '');
-        $ctx->zadd($foot, $skel .= msg_reply($ctx, $hdr));
+        print { $ctx->zfh } $foot, qq(<a\nhref="#R">reply</a>),
+                                $skel, '</pre>', @related,
+                                msg_reply($ctx, $hdr);
 }
 
 sub ghost_parent {