www_coderepo: use OnDestroy to render summary view

This lets us get rid of a /bin/sh process and allows us us to
rely on Qspawn to parallelize git commands.

Special treatment of the OnDestroy object is necessary to keep
its scope limited for MockHTTP.  Neither the generic `plackup'
HTTP server and nor our -httpd/-netd needed this scope
limitation.  As a result, summary() is now called inside an
anonymous sub to keep the memory overhead of the anonymous sub
itself as small as possible.  Avoiding anonymous subs entirely
would be preferable for memory savings, but it's necessary for
PSGI.

diff --git a/lib/PublicInbox/WwwCoderepo.pm b/lib/PublicInbox/WwwCoderepo.pm
index 52ab6e4800b3930af46991f6e5059ecfcb6bc4b9..bece45af54c9bd79c4b6e3df6fb5e0e1a426ca35 100644 (file)
--- a/lib/PublicInbox/WwwCoderepo.pm
+++ b/lib/PublicInbox/WwwCoderepo.pm
@@ -19,6 +19,7 @@ use PublicInbox::ViewDiff qw(uri_escape_path);
 use PublicInbox::RepoSnapshot;
 use PublicInbox::RepoAtom;
 use PublicInbox::RepoTree;
+use PublicInbox::OnDestroy;
 
 my @EACH_REF = (qw(git for-each-ref --sort=-creatordate),
                "--format=%(HEAD)%00".join('%00', map { "%($_)" }
@@ -120,15 +121,13 @@ sub _refs_tags_link {
                "</a>$align ", ascii_html($s), " ($cd)", @snap_fmt, "\n");
 }
 
-sub summary_finish {
+sub summary_END { # called via OnDestroy
        my ($ctx) = @_;
-       my $wcb = delete($ctx->{env}->{'qspawn.wcb'}) or return; # already done
-       my @x = split(/\n\n/sm, delete($ctx->{-each_refs}), 3);
+       my $wcb = delete($ctx->{-wcb}) or return; # already done
        PublicInbox::WwwStream::html_init($ctx);
        my $zfh = $ctx->zfh;
 
-       # git log
-       my @r = split(/\n/s, pop(@x));
+       my @r = split(/\n/s, delete($ctx->{qx_res}->{'log'}) // '');
        my $last = scalar(@r) > $ctx->{wcr}->{summary_log} ? pop(@r) : undef;
        my $tip_html = '';
        my $tip = $ctx->{qp}->{h};
@@ -149,7 +148,7 @@ EOM
        print $zfh "...\n" if $last;
 
        # README
-       my ($bref, $oid, $ref_path) = @{delete $ctx->{-readme}};
+       my ($bref, $oid, $ref_path) = @{delete $ctx->{qx_res}->{readme}};
        if ($bref) {
                my $l = PublicInbox::Linkify->new;
                $$bref =~ s/\s*\z//sm;
@@ -163,14 +162,14 @@ EOM
 
        # refs/heads
        print $zfh '<a id=heads>', $HEADS_CMD , '</a>';
-       @r = split(/^/sm, shift(@x) // '');
+       @r = split(/^/sm, delete($ctx->{qx_res}->{heads}) // '');
        $last = scalar(@r) > $ctx->{wcr}->{summary_branches} ? pop(@r) : undef;
        chomp(@r);
        for (@r) { print $zfh _refs_heads_link($_, './') }
        print $zfh $NO_HEADS if !@r;
        print $zfh qq(<a href="refs/heads/">...</a>\n) if $last;
        print $zfh "\n<a id=tags>", $TAGS_CMD, '</a>';
-       @r = split(/^/sm, shift(@x) // '');
+       @r = split(/^/sm, delete($ctx->{qx_res}->{tags}) // '');
        $last = scalar(@r) > $ctx->{wcr}->{summary_tags} ? pop(@r) : undef;
        my ($snap_pfx, @snap_fmt) = _snapshot_link_prep($ctx);
        chomp @r;
@@ -180,54 +179,56 @@ EOM
        $wcb->($ctx->html_done('</pre>'));
 }
 
-sub capture_refs ($$) { # psgi_qx callback to capture git-for-each-ref + git-log
-       my ($bref, $ctx) = @_;
-       my $qsp_err = delete $ctx->{-qsp_err};
+sub capture { # psgi_qx callback to capture git-for-each-ref
+       my ($bref, $arg) = @_; # arg = [ctx, key, OnDestroy(summary_END)]
        utf8::decode($$bref);
-       $ctx->{-each_refs} = $$bref;
-       summary_finish($ctx) if $ctx->{-readme};
+       $arg->[0]->{qx_res}->{$arg->[1]} = $$bref;
+       # summary_END may be called via OnDestroy $arg->[2]
 }
 
 sub set_readme { # git->cat_async callback
        my ($bref, $oid, $type, $size, $ctx) = @_;
-       my $ref_path = shift @{$ctx->{-nr_readme_tries}}; # e.g. HEAD:README
-       if ($type eq 'blob' && !$ctx->{-readme}) {
-               $ctx->{-readme} = [ $bref, $oid, $ref_path ];
-       } elsif (scalar @{$ctx->{-nr_readme_tries}} == 0) {
-               $ctx->{-readme} //= []; # nothing left to try
+       my $ref_path = shift @{$ctx->{-readme_tries}}; # e.g. HEAD:README
+       if ($type eq 'blob' && !$ctx->{qx_res}->{readme}) {
+               $ctx->{qx_res}->{readme} = [ $bref, $oid, $ref_path ];
+       } elsif (scalar @{$ctx->{-readme_tries}} == 0) {
+               $ctx->{qx_res}->{readme} //= []; # nothing left to try
        } # or try another README...
-       summary_finish($ctx) if $ctx->{-each_refs} && $ctx->{-readme};
+       # summary_END may be called via OnDestroy ($ctx->{-END})
 }
 
-sub summary {
-       my ($self, $ctx) = @_;
-       $ctx->{wcr} = $self;
+sub summary ($$) {
+       my ($ctx, $wcb) = @_;
+       $ctx->{-wcb} = $wcb; # PublicInbox::HTTP::{Identity,Chunked}
        my $tip = $ctx->{qp}->{h}; # same as cgit
        if (defined $tip && $tip eq '') {
                delete $ctx->{qp}->{h};
                undef($tip);
        }
-       my $nb = $self->{summary_branches} + 1;
-       my $nt = $self->{summary_tags} + 1;
-       my $nl = $self->{summary_log} + 1;
+       my ($nb, $nt, $nl) = map { $_ + 1 } @{$ctx->{wcr}}{qw(
+               summary_branches summary_tags summary_log)};
+       $ctx->{qx_res} = {};
+       my $qsp_err = \($ctx->{-qsp_err} = '');
+       my %opt = (quiet => 1, 2 => $ctx->{wcr}->{log_fh});
+       my %env = (GIT_DIR => $ctx->{git}->{git_dir});
+       my @log = (qw(git log), "-$nl", '--pretty=format:%d %H %h %cs %s');
+       push(@log, $tip) if defined $tip;
 
-       my @cmd = (qw(/bin/sh -c),
-               "$EACH_REF --count=$nb refs/heads; echo && " .
-               "$EACH_REF --count=$nt refs/tags; echo && " .
-               qq(git log -$nl --pretty=format:'%d %H %h %cs %s' "\$@" --));
-       push @cmd, 'git', $tip if defined($tip);
-       my $qsp = PublicInbox::Qspawn->new(\@cmd,
-               { GIT_DIR => $ctx->{git}->{git_dir} },
-               { quiet => 1, 2 => $self->{log_fh} });
-       $qsp->{qsp_err} = \($ctx->{-qsp_err} = '');
+       # limit scope for MockHTTP test (t/solver_git.t)
+       my $END = PublicInbox::OnDestroy->new($$, \&summary_END, $ctx);
+       for (['log', \@log],
+                [ 'heads', [@EACH_REF, "--count=$nb", 'refs/heads'] ],
+                [ 'tags', [@EACH_REF, "--count=$nt", 'refs/tags'] ]) {
+               my ($k, $cmd) = @$_;
+               my $qsp = PublicInbox::Qspawn->new($cmd, \%env, \%opt);
+               $qsp->{qsp_err} = $qsp_err;
+               $qsp->psgi_qx($ctx->{env}, undef, \&capture,
+                               [$ctx, $k, $END]);
+       }
        $tip //= 'HEAD';
        my @try = ("$tip:README", "$tip:README.md"); # TODO: configurable
-       $ctx->{-nr_readme_tries} = [ @try ];
-       PublicInbox::ViewVCS::do_cat_async($ctx, \&set_readme, @try);
-       sub { # $_[0] => PublicInbox::HTTP::{Identity,Chunked}
-               $ctx->{env}->{'qspawn.wcb'} = $_[0];
-               $qsp->psgi_qx($ctx->{env}, undef, \&capture_refs, $ctx);
-       }
+       my %ctx = (%$ctx, -END => $END, -readme_tries => [ @try ]);
+       PublicInbox::ViewVCS::do_cat_async(\%ctx, \&set_readme, @try);
 }
 
 # called by GzipFilter->close after translate
@@ -293,7 +294,8 @@ sub srv { # endpoint called by PublicInbox::WWW
                ($git = $cr->{$1})) {
                        PublicInbox::GitHTTPBackend::serve($ctx->{env},$git,$2);
        } elsif ($path_info =~ m!\A/(.+?)/\z! and ($ctx->{git} = $cr->{$1})) {
-               summary($self, $ctx)
+               $ctx->{wcr} = $self;
+               sub { summary($ctx, $_[0]) }; # $_[0] = wcb
        } elsif ($path_info =~ m!\A/(.+?)/([a-f0-9]+)/s/([^/]+)?\z! and
                        ($ctx->{git} = $cr->{$1})) {
                $ctx->{lh} = $self->{log_fh};