From 5b39ed2b6b3d5d8c24240f1b1df8bfd751b0e6bc Mon Sep 17 00:00:00 2001
From: Eric Wong <e@80x24.org>
Date: Wed, 5 Oct 2022 22:29:41 +0000
Subject: [PATCH] www: support publicinbox.cgit knob

For backwards-compatibility, this defaults to `first'.  When set
to `fallback', PublicInbox::WwwCoderepo is favored and cgit is
only used as a fallback.  Eventually, `rewrite' will also be
supported to rewrite cgit URLs to WwwCoderepo ones.

Of course, WwwCoderepo is still missing search and other key
features, but that's being worked on...
---
 Documentation/public-inbox-config.pod | 26 +++++++++++++++++++++++
 lib/PublicInbox/Cgit.pm               |  1 +
 lib/PublicInbox/WWW.pm                | 30 +++++++++++++++------------
 3 files changed, 44 insertions(+), 13 deletions(-)

diff --git a/Documentation/public-inbox-config.pod b/Documentation/public-inbox-config.pod
index d8504e61..e926a27b 100644
--- a/Documentation/public-inbox-config.pod
+++ b/Documentation/public-inbox-config.pod
@@ -293,6 +293,32 @@ C<publicinbox.cgitbin>, but may be overridden.
 Default: basename of C<publicinbox.cgitbin>, /var/www/htdocs/cgit/
 or /usr/share/cgit/
 
+=item publicinbox.cgit
+
+Controls whether or not and how C<cgit> is used for serving coderepos.
+New in public-inbox 2.0.0 (PENDING).
+
+=over 8
+
+=item * first
+
+Try using C<cgit> as the first choice, this is the default.
+
+=item * fallback
+
+Fall back to using C<cgit> only if our native, inbox-aware
+git code repository viewer doesn't recognized the URL.
+
+=item * rewrite
+
+Rewrite C<cgit> URLs for our native, inbox-aware code repository viewer.
+This implies C<fallback> for URLs the native viewer does not recognize.
+
+=back
+
+Default: C<first>  (C<cgit> will be used iff C<publicinbox.cgitrc>
+is set and the C<cgit> binary exists).
+
 =item publicinbox.mailEditor
 
 See L<public-inbox-edit(1)>
diff --git a/lib/PublicInbox/Cgit.pm b/lib/PublicInbox/Cgit.pm
index 298663c7..336098ca 100644
--- a/lib/PublicInbox/Cgit.pm
+++ b/lib/PublicInbox/Cgit.pm
@@ -53,6 +53,7 @@ sub locate_cgit ($) {
 sub new {
 	my ($class, $pi_cfg) = @_;
 	my ($cgit_bin, $cgit_data) = locate_cgit($pi_cfg);
+	$cgit_bin // return; # fall back in WWW->cgit
 	my $self = bless {
 		cmd => [ $cgit_bin ],
 		cgit_data => $cgit_data,
diff --git a/lib/PublicInbox/WWW.pm b/lib/PublicInbox/WWW.pm
index 470510ae..f861b192 100644
--- a/lib/PublicInbox/WWW.pm
+++ b/lib/PublicInbox/WWW.pm
@@ -194,12 +194,19 @@ sub r404 {
 
 sub news_cgit_fallback ($) {
 	my ($ctx) = @_;
-	my $www = $ctx->{www};
-	my $env = $ctx->{env};
-	my $res = $www->news_www->call($env);
-	$res = $www->cgit->call($env, $ctx) if $res->[0] == 404;
+	my $res = $ctx->{www}->news_www->call($ctx->{env});
+
+	$res->[0] == 404 and ($ctx->{www}->{cgit_fallback} //= do {
+		my $c = $ctx->{www}->{pi_cfg}->{'publicinbox.cgit'} // 'first';
+		$c ne 'first' # `fallback' and `rewrite' => true
+	} // 0) and $res = $ctx->{www}->coderepo->srv($ctx);
+
 	ref($res) eq 'ARRAY' && $res->[0] == 404 and
-		$res = $www->coderepo->srv($ctx);
+		$res = $ctx->{www}->cgit->call($ctx->{env}, $ctx);
+
+	ref($res) eq 'ARRAY' && $res->[0] == 404 &&
+			!$ctx->{www}->{cgit_fallback} and
+		$res = $ctx->{www}->coderepo->srv($ctx);
 	$res;
 }
 
@@ -484,17 +491,14 @@ sub news_www {
 
 sub cgit {
 	my ($self) = @_;
-	$self->{cgit} //= do {
-		my $pi_cfg = $self->{pi_cfg};
-
-		if (defined($pi_cfg->{'publicinbox.cgitrc'})) {
+	$self->{cgit} //=
+		(defined($self->{pi_cfg}->{'publicinbox.cgitrc'}) ? do {
 			require PublicInbox::Cgit;
-			PublicInbox::Cgit->new($pi_cfg);
-		} else {
+			PublicInbox::Cgit->new($self->{pi_cfg});
+		} : undef) // do {
 			require Plack::Util;
 			Plack::Util::inline_object(call => sub { r404() });
-		}
-	}
+		};
 }
 
 sub coderepo {
-- 
2.44.0