view: cull redundant phrases in subjects

There is no need to show the same phrases over and over again
in thread skeletons, it adds to visual noise and makes things
more difficult to read.

diff --git a/lib/PublicInbox/View.pm b/lib/PublicInbox/View.pm
index e96f773f32bebb37d4fa68d72aa24b9ca2890859..7454acbba153bc80f86ae09f4c931c36bb007a5b 100644 (file)
--- a/lib/PublicInbox/View.pm
+++ b/lib/PublicInbox/View.pm
@@ -368,7 +368,6 @@ sub thread_html {
        $ctx->{prev_attr} = '';
        $ctx->{prev_level} = 0;
        $ctx->{root_anchor} = anchor_for($mid);
-       $ctx->{seen} = {};
        $ctx->{mapping} = {};
        $ctx->{s_nr} = "$nr+ messages in thread";
 
@@ -597,8 +596,9 @@ sub thread_skel {
        $$dst .= "$nr+ messages in thread ($expand";
        $$dst .= qq! / <a\nhref="#b">[top]</a>)\n!;
 
-       my $subj = $srch->subject_path($hdr->header('Subject'));
-       $ctx->{seen} = { $subj => 1 };
+       my $subj = $hdr->header('Subject');
+       defined $subj or $subj = '';
+       $ctx->{prev_subj} = [ split(/ /, $srch->subject_normalized($subj)) ];
        $ctx->{cur} = $mid;
        $ctx->{prev_attr} = '';
        $ctx->{prev_level} = 0;
@@ -793,20 +793,31 @@ sub skel_dump {
        # Subject is never undef, this mail was loaded from
        # our Xapian which would've resulted in '' if it were
        # really missing (and Filter rejects empty subjects)
-       my $subj = $smsg->subject;
-       my $h = $ctx->{srch}->subject_path($subj);
-       if ($ctx->{seen}->{$h}) {
-               $subj = undef;
-       } else {
-               $ctx->{seen}->{$h} = 1;
-               $subj = PublicInbox::Hval->new($subj);
-               $subj = $subj->as_html;
+       my @subj = split(/ /, $ctx->{srch}->subject_normalized($smsg->subject));
+
+       # remove common suffixes from the subject if it matches the previous,
+       # so we do not show redundant text at the end.
+       my $prev_subj = $ctx->{prev_subj} || [];
+       $ctx->{prev_subj} = [ @subj ];
+       my $omit = ''; # '"' denotes identical text omitted
+       while (@$prev_subj && @subj && $subj[-1] eq $prev_subj->[-1]) {
+               pop @$prev_subj;
+               pop @subj;
+               $omit ||= '&#34; ';
+       }
+       pop @subj if @subj && $subj[-1] =~ /^re:\s*/i;
+       my $end;
+       if (@subj) {
+               my $subj = join(' ', @subj);
+               $subj = ascii_html($subj);
                obfuscate_addrs($obfs_ibx, $subj) if $obfs_ibx;
+               $end = "$subj</a> $omit$f\n"
+       } else {
+               $end = "$f</a>\n";
        }
        my $m;
        my $id = '';
        my $mapping = $ctx->{mapping};
-       my $end = defined($subj) ? "$subj</a> $f\n" : "$f</a>\n";
        if ($mapping) {
                my $map = $mapping->{$mid};
                $id = id_compress($mid, 1);
@@ -900,6 +911,7 @@ sub dump_topics {
        my @out;
        my $ibx = $ctx->{-inbox};
        my $obfs_ibx = $ibx->{obfuscate} ? $ibx : undef;
+       my $srch = $ctx->{srch};
 
        # sort by recency, this allows new posts to "bump" old topics...
        foreach my $topic (sort { $b->[0] <=> $a->[0] } @$order) {
@@ -908,6 +920,7 @@ sub dump_topics {
                next unless defined $top;  # ghost topic
                my $mid = delete $seen->{$top};
                my $href = mid_escape($mid);
+               my $prev_subj = [ split(/ /, $top) ];
                $top = PublicInbox::Hval->new($top)->as_html;
                $ts = fmt_ts($ts);
 
@@ -930,11 +943,22 @@ sub dump_topics {
                        my $level = $ex[$i];
                        my $subj = $ex[$i + 1];
                        $mid = delete $seen->{$subj};
-                       $subj = ascii_html($subj);
+                       my @subj = split(/ /, $srch->subject_normalized($subj));
+                       my @next_prev = @subj; # full copy
+                       my $omit = ''; # '"' denotes identical text omitted
+                       while (@$prev_subj && @subj &&
+                                       $subj[-1] eq $prev_subj->[-1]) {
+                               pop @$prev_subj;
+                               pop @subj;
+                               $omit ||= ' &#34;';
+                       }
+                       pop @subj if @subj && $subj[-1] =~ /^re:\s*/i;
+                       $prev_subj = \@next_prev;
+                       $subj = ascii_html(join(' ', @subj));
                        obfuscate_addrs($obfs_ibx, $subj) if $obfs_ibx;
                        $href = mid_escape($mid);
                        $s .= indent_for($level) . TCHILD;
-                       $s .= "<a\nhref=\"$href/T/#u\">$subj</a>\n";
+                       $s .= "<a\nhref=\"$href/T/#u\">$subj</a>$omit\n";
                }
                push @out, $s;
        }