1 files changed, 153 insertions, 0 deletions
diff --git a/lib/PublicInbox/ManifestJsGz.pm b/lib/PublicInbox/ManifestJsGz.pm
new file mode 100644
index 00000000..328303ce
--- /dev/null
+++ b/lib/PublicInbox/ManifestJsGz.pm
@@ -0,0 +1,153 @@
+# Copyright (C) 2020 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+package PublicInbox::ManifestJsGz;
+use strict;
+use v5.10.1;
+use Digest::SHA ();
+use File::Spec ();
+use bytes (); # length
+use PublicInbox::Inbox;
+use PublicInbox::Git;
+use IO::Compress::Gzip qw(gzip);
+use HTTP::Date qw(time2str);
+*try_cat = \&PublicInbox::Inbox::try_cat;
+
+our $json;
+for my $mod (qw(JSON::MaybeXS JSON JSON::PP)) {
+        eval "require $mod" or next;
+        # ->ascii encodes non-ASCII to "\uXXXX"
+        $json = $mod->new->ascii(1) and last;
+}
+
+sub response {
+        my ($env, $list) = @_;
+        $json or return [ 404, [], [] ];
+        my $self = bless {
+                -abs2urlpath => {},
+                -mtime => 0,
+                manifest => {},
+                -list => $list,
+                psgi_env => $env,
+        }, __PACKAGE__;
+
+        # PSGI server will call this immediately and give us a callback (-wcb)
+        sub {
+                $self->{-wcb} = $_[0]; # HTTP write callback
+                iterate_start($self);
+        };
+}
+
+sub fingerprint ($) {
+        my ($git) = @_;
+        # TODO: convert to qspawn for fairness when there's
+        # thousands of repos
+        my ($fh, $pid) = $git->popen('show-ref');
+        my $dig = Digest::SHA->new(1);
+        while (read($fh, my $buf, 65536)) {
+                $dig->add($buf);
+        }
+        close $fh;
+        waitpid($pid, 0);
+        return if $?; # empty, uninitialized git repo
+        $dig->hexdigest;
+}
+
+sub manifest_add ($$;$$) {
+        my ($self, $ibx, $epoch, $default_desc) = @_;
+        my $url_path = "/$ibx->{name}";
+        my $git_dir = $ibx->{inboxdir};
+        if (defined $epoch) {
+                $git_dir .= "/git/$epoch.git";
+                $url_path .= "/git/$epoch.git";
+        }
+        return unless -d $git_dir;
+        my $git = PublicInbox::Git->new($git_dir);
+        my $fingerprint = fingerprint($git) or return; # no empty repos
+
+        chomp(my $owner = $git->qx('config', 'gitweb.owner'));
+        chomp(my $desc = try_cat("$git_dir/description"));
+        utf8::decode($owner);
+        utf8::decode($desc);
+        $owner = undef if $owner eq '';
+        $desc = 'Unnamed repository' if $desc eq '';
+
+        # templates/hooks--update.sample and git-multimail in git.git
+        # only match "Unnamed repository", not the full contents of
+        # templates/this--description in git.git
+        if ($desc =~ /\AUnnamed repository/) {
+                $desc = "$default_desc [epoch $epoch]" if defined($epoch);
+        }
+
+        my $reference;
+        chomp(my $alt = try_cat("$git_dir/objects/info/alternates"));
+        if ($alt) {
+                # n.b.: GitPython doesn't seem to handle comments or C-quoted
+                # strings like native git does; and we don't for now, either.
+                my @alt = split(/\n+/, $alt);
+
+                # grokmirror only supports 1 alternate for "reference",
+                if (scalar(@alt) == 1) {
+                        my $objdir = "$git_dir/objects";
+                        $reference = File::Spec->rel2abs($alt[0], $objdir);
+                        $reference =~ s!/[^/]+/?\z!!; # basename
+                }
+        }
+        $self->{-abs2urlpath}->{$git_dir} = $url_path;
+        my $modified = $git->modified;
+        if ($modified > $self->{-mtime}) {
+                $self->{-mtime} = $modified;
+        }
+        $self->{manifest}->{$url_path} = {
+                owner => $owner,
+                reference => $reference,
+                description => $desc,
+                modified => $modified,
+                fingerprint => $fingerprint,
+        };
+}
+
+sub iterate_start {
+        my ($self) = @_;
+        if (my $async = $self->{psgi_env}->{'pi-httpd.async'}) {
+                # PublicInbox::HTTPD::Async->new
+                $async->(undef, undef, $self);
+        } else {
+                event_step($self) while $self->{-wcb};
+        }
+}
+
+sub event_step {
+        my ($self) = @_;
+        while (my $ibx = shift(@{$self->{-list}})) {
+                eval {
+                        if (defined(my $max = $ibx->max_git_epoch)) {
+                                my $desc = $ibx->description;
+                                for my $epoch (0..$max) {
+                                        manifest_add($self, $ibx, $epoch, $desc)
+                                }
+                        } else {
+                                manifest_add($self, $ibx);
+                        }
+                };
+                warn "E: $@" if $@;
+                if (my $async = $self->{psgi_env}->{'pi-httpd.async'}) {
+                        # PublicInbox::HTTPD::Async->new
+                        $async->(undef, undef, $self);
+                }
+                return; # more steps needed
+        }
+        my $abs2urlpath = delete $self->{-abs2urlpath};
+        my $wcb = delete $self->{-wcb};
+        my $manifest = delete $self->{manifest};
+        while (my ($url_path, $repo) = each %$manifest) {
+                defined(my $abs = $repo->{reference}) or next;
+                $repo->{reference} = $abs2urlpath->{$abs};
+        }
+        $manifest = $json->encode($manifest);
+        gzip(\$manifest => \(my $out));
+        $wcb->([ 200, [ qw(Content-Type application/gzip),
+                 'Last-Modified', time2str($self->{-mtime}),
+                 'Content-Length', bytes::length($out) ], [ $out ] ]);
+}
+
+1;