From 5f09452bb7e6cf49fb6eb7e6cf166a7c3cdc5433 Mon Sep 17 00:00:00 2001
From: Eric Wong <e@80x24.org>
Date: Thu, 29 Jun 2017 21:48:30 +0000
Subject: 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.
---
 lib/PublicInbox/View.pm | 52 ++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 38 insertions(+), 14 deletions(-)

(limited to 'lib/PublicInbox/View.pm')

diff --git a/lib/PublicInbox/View.pm b/lib/PublicInbox/View.pm
index e96f773f..7454acbb 100644
--- 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;
 	}
-- 
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