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, 4 insertions, 3 deletions

diff --git a/lib/PublicInbox/WwwStream.pm b/lib/PublicInbox/WwwStream.pm
index 2a318e5e..77b6f9c2 100644
--- a/lib/PublicInbox/WwwStream.pm
+++ b/lib/PublicInbox/WwwStream.pm
@@ -181,11 +181,12 @@ sub html_oneshot ($$;@) {
                 'Content-Length' => undef ];
         bless $ctx, __PACKAGE__;
         $ctx->{gz} = PublicInbox::GzipFilter::gz_or_noop($res_hdr, $ctx->{env});
+        my @top;
         $ctx->{base_url} // do {
-                $ctx->zadd(html_top($ctx));
+                @top = html_top($ctx);
                 $ctx->{base_url} = base_url($ctx);
         };
-        my $bdy = $ctx->zflush(@_[2..$#_], _html_end($ctx));
+        my $bdy = $ctx->zflush(@top, @_[2..$#_], _html_end($ctx));
         $res_hdr->[3] = length($bdy);
         [ $code, $res_hdr, [ $bdy ] ]
 }
@@ -216,7 +217,7 @@ sub html_init {
         my $h = $ctx->{-res_hdr} = ['Content-Type', 'text/html; charset=UTF-8'];
         $ctx->{gz} = PublicInbox::GzipFilter::gz_or_noop($h, $ctx->{env});
         bless $ctx, __PACKAGE__;
-        $ctx->zadd(html_top($ctx));
+        print { $ctx->zfh } html_top($ctx);
 }
 
 1;