nntp: XHDR lookups by Message-ID may cross groups

This is allowed by RFC 2980 and HDR (to-be-implemented) in
RFC 3977 supports it, too.

1 files changed, 38 insertions, 17 deletions

diff --git a/lib/PublicInbox/NNTP.pm b/lib/PublicInbox/NNTP.pm
index c8ef01e2..19e08482 100644
--- a/lib/PublicInbox/NNTP.pm
+++ b/lib/PublicInbox/NNTP.pm
@@ -544,17 +544,18 @@ sub long_response ($$$$) {
 sub xhdr_message_id ($$) { # optimize XHDR Message-ID [range] for slrnpull.
         my ($self, $range) = @_;
 
-        my $mm = $self->{ng}->mm;
         if (defined $range && $range =~ /\A<(.+)>\z/) { # Message-ID
-                my $n = $mm->num_for($1);
+                my ($ng, $n) = mid_lookup($self, $1);
                 return '430 No article with that message-id' unless $n;
                 more($self, '221 Header follows');
+                my $self_ng = $self->{ng};
                 more($self, "$range $range");
                 '.';
         } else { # numeric range
                 $range = $self->{article} unless defined $range;
                 my $r = get_range($self, $range);
                 return $r unless ref $r;
+                my $mm = $self->{ng}->mm;
                 my ($beg, $end) = @$r;
                 more($self, '221 Header follows');
                 $self->long_response($beg, $end, sub {
@@ -570,20 +571,36 @@ sub xref ($$) {
         "$ng->{domain} $ng->{name}:$n"
 }
 
+sub mid_lookup ($$) {
+        my ($self, $mid) = @_;
+        my $self_ng = $self->{ng};
+        if ($self_ng) {
+                my $n = $self_ng->mm->num_for($mid);
+                return ($self_ng, $n) if defined $n;
+        }
+        foreach my $ng (values %{$self->{nntpd}->{groups}}) {
+                next if $ng eq $self_ng;
+                my $n = $ng->mm->num_for($mid);
+                return ($ng, $n) if defined $n;
+        }
+        (undef, undef);
+}
+
 sub xhdr_xref ($$) { # optimize XHDR Xref [range] for rtin
         my ($self, $range) = @_;
 
-        my $ng = $self->{ng};
-        my $mm = $ng->mm;
         if (defined $range && $range =~ /\A<(.+)>\z/) { # Message-ID
-                my $n = $mm->num_for($1);
+                my ($ng, $n) = mid_lookup($self, $1);
+                return '430 No article with that message-id' unless $n;
                 more($self, '221 Header follows');
-                more($self, "$range ".xref($ng, $n)) if defined $n;
+                more($self, "$range ".xref($ng, $n));
                 '.';
         } else { # numeric range
                 $range = $self->{article} unless defined $range;
                 my $r = get_range($self, $range);
                 return $r unless ref $r;
+                my $ng = $self->{ng};
+                my $mm = $ng->mm;
                 my ($beg, $end) = @$r;
                 more($self, '221 Header follows');
                 $self->long_response($beg, $end, sub {
@@ -605,7 +622,6 @@ sub header_obj_for {
 
 sub xhdr_searchmsg ($$$) {
         my ($self, $sub, $range) = @_;
-        my $srch = $self->{ng}->search;
         my $emit = ($sub eq 'date') ? sub {
                 my ($pfx, $m) = @_;
                 my @t = gmtime($m->header('X-PI-TS'));
@@ -617,12 +633,20 @@ sub xhdr_searchmsg ($$$) {
         };
 
         if (defined $range && $range =~ /\A<(.+)>\z/) { # Message-ID
-                more($self, '221 Header follows');
-                my $m = header_obj_for($srch, $1);
-                $emit->($range, $m) if defined $m;
-                '.';
+                my ($ng, $n) = mid_lookup($self, $1);
+                return '430 No article with that message-id' unless $n;
+                if (my $srch = $ng->search) {
+                        more($self, '221 Header follows');
+                        my $m = header_obj_for($srch, $range);
+                        $emit->($range, $m) if defined $m;
+                        '.';
+                } else {
+                        xhdr_slow($self, $sub, $range);
+                }
         } else { # numeric range
                 $range = $self->{article} unless defined $range;
+                my $srch = $self->{ng}->search or
+                                return xhdr_slow($self, $sub, $range);
                 my $mm = $self->{ng}->mm;
                 my $r = get_range($self, $range);
                 return $r unless ref $r;
@@ -639,14 +663,12 @@ sub xhdr_searchmsg ($$$) {
 
 sub cmd_xhdr ($$;$) {
         my ($self, $header, $range) = @_;
-        my $ng = $self->{ng};
-        defined $ng or return '412 no news group currently selected';
         my $sub = lc $header;
         if ($sub eq 'message-id') {
                 xhdr_message_id($self, $range);
         } elsif ($sub eq 'xref') {
                 xhdr_xref($self, $range);
-        } elsif ($sub =~ /\A(subject|references|date)\z/ && $ng->search) {
+        } elsif ($sub =~ /\A(subject|references|date)\z/) {
                 xhdr_searchmsg($self, $sub, $range);
         } else {
                 xhdr_slow($self, $header, $range);
@@ -660,9 +682,8 @@ sub xhdr_slow ($$$) {
                 my $r = $self->art_lookup($range, 2);
                 return $r unless ref $r;
                 more($self, '221 Header follows');
-                if (defined($r = xhdr($r, $header))) {
-                        more($self, "$range $r");
-                }
+                $r = xhdr($r, $header);
+                more($self, "$range $r") if defined $r;
                 '.';
         } else { # numeric range
                 $range = $self->{article} unless defined $range;