repobrowse: implement Atom feed

Mostly following cgit, except we do not serve redundant
text-only output which wastes bandwidth and doesn't preserve
pre-formatting layout which is critical to some messages.

2 files changed, 118 insertions, 1 deletions

diff --git a/lib/PublicInbox/Repobrowse.pm b/lib/PublicInbox/Repobrowse.pm
index 91d0ab20..82d38f90 100644
--- a/lib/PublicInbox/Repobrowse.pm
+++ b/lib/PublicInbox/Repobrowse.pm
@@ -23,7 +23,7 @@ use warnings;
 use URI::Escape qw(uri_escape_utf8 uri_unescape);
 use PublicInbox::RepobrowseConfig;
 
-my %CMD = map { lc($_) => $_ } qw(Log Commit Tree Patch Blob Plain Tag);
+my %CMD = map { lc($_) => $_ } qw(Log Commit Tree Patch Blob Plain Tag Atom);
 my %VCS = (git => 'Git');
 my %LOADED;
 
diff --git a/lib/PublicInbox/RepobrowseGitAtom.pm b/lib/PublicInbox/RepobrowseGitAtom.pm
new file mode 100644
index 00000000..9326841d
--- /dev/null
+++ b/lib/PublicInbox/RepobrowseGitAtom.pm
@@ -0,0 +1,117 @@
+# Copyright (C) 2016 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+
+# show log as an Atom feed
+package PublicInbox::RepobrowseGitAtom;
+use strict;
+use warnings;
+use PublicInbox::Hval qw(utf8_html);
+use base qw(PublicInbox::RepobrowseBase);
+my $ATOM_FMT = '--pretty=tformat:'.
+                join('%x00', qw(%s %ct %an %ae %at %h %H %b), '', '');
+
+use constant DATEFMT => '%Y-%m-%dT%H:%M:%SZ';
+use POSIX qw(strftime);
+
+sub call_git_atom {
+        my ($self, $req) = @_;
+        my $repo_info = $req->{repo_info};
+        my $max = $repo_info->{max_commit_count} || 10;
+        $max = int($max);
+        $max = 50 if $max == 0;
+
+        my $git = $repo_info->{git};
+        my $q = PublicInbox::RepobrowseGitQuery->new($req->{cgi});
+        my $h = $q->{h};
+        $h eq '' and chomp($h = $git->qx(qw(symbolic-ref --short HEAD)));
+
+        my @cmd = (qw(log --no-notes --no-color --abbrev-commit),
+                        $git->abbrev, $ATOM_FMT, "-$max", $h, '--');
+        push @cmd, $req->{expath} if length($req->{expath});
+        my $log = $git->popen(@cmd);
+
+        sub {
+                my ($res) = @_; # Plack callback
+                my @h = ( 'Content-Type' => 'application/atom+xml' );
+                my $fh = $res->([200, \@h]);
+                $self->git_atom_stream($req, $q, $log, $fh, $h);
+                $fh->close;
+        }
+}
+
+sub repo_root_url {
+        my ($self, $req) = @_;
+        my $cgi = $req->{cgi};
+        my $uri = $cgi->request_uri;
+        $uri =~ s/\?.+\z//; # no query string
+        my @uri = split(m!/+!, $uri);
+        shift @uri; # leading slash
+        my @extra = @{$req->{extra}};
+        while (@uri && @extra && $uri[-1] eq $extra[-1]) {
+                pop @uri;
+                pop @extra;
+        }
+        pop @uri if $uri[-1] eq 'atom'; # warn if not equal?
+        $cgi->base . join('/', @uri);
+}
+
+sub git_atom_stream {
+        my ($self, $req, $q, $log, $fh, $h) = @_;
+        my $repo_info = $req->{repo_info};
+        my $title = join('/', $repo_info->{repo}, @{$req->{extra}});
+        $title = utf8_html("$title, branch $h");
+
+        my $url = $self->repo_root_url($req);
+        $fh->write(qq(<?xml version="1.0"?>\n) .
+                qq(<feed\nxmlns="http://www.w3.org/2005/Atom">) .
+                qq(<title>$title</title>) .
+                qq(<subtitle>$repo_info->{desc_html}</subtitle>) .
+                qq(<link\nrel="alternate"\ntype="text/html"\nhref="$url"\n/>));
+        my $rel = $req->{relcmd};
+        my %acache;
+        local $/ = "\0";
+        while (defined(my $s = <$log>)) {
+                chomp $s;
+                my $entry = '<entry><title>';
+                $entry .= utf8_html($s); # commit subject
+                $entry .= '</title><updated>';
+
+                chomp($s = <$log>); # commit time
+                $entry .= strftime(DATEFMT, gmtime($s));
+                $entry .= '</updated><author><name>';
+
+                chomp($s = <$log>); # author name
+                $entry .= $acache{$s} ||= utf8_html($s);
+                $entry .= '</name><email>';
+
+                chomp($s = <$log>); # author email
+                $entry .= $acache{$s} ||= utf8_html($s);
+                $entry .= '</email></author><published>';
+
+                chomp($s = <$log>); # author time
+                $entry .= strftime(DATEFMT, gmtime($s));
+                $entry .= '</published>';
+
+                $entry .= qq(<link\nrel="alternate"\ntype="text/html"\nhref=");
+                $entry .= $url;
+                chomp($s = <$log>); # abbreviated commit hash for URL
+                $entry .= qq(/commit?id=$s"\n/><id>);
+                chomp($s = <$log>); # unabbreviated commit hash
+                $entry .= $s;
+                $entry .= qq(</id>);
+
+                $entry .= qq(<content\ntype="xhtml"><div\nxmlns=");
+                $entry .= qq(http://www.w3.org/1999/xhtml">);
+                $entry .= qq(<pre\nstyle="white-space:pre-wrap">\n);
+                chomp($s = <$log>);
+                $entry .= utf8_html($s);  # body
+                $fh->write($entry .= qq(</pre></div></content></entry>));
+                eval {
+                        local $/ = "\0\n";
+                        $s = <$log>;
+                };
+        }
+        $fh->write('</feed>');
+}
+
+1;