gitweb: New improved formatting of chunk header in diff

If we have provided enough info, and diff is not combined diff,
and if provided diff line is chunk header, then:
* split chunk header into .chunk_info and .section span elements,
  first containing proper chunk header, second section heading
  (aka. which function), for separate styling: the proper chunk
  header is on non-white background, section heading part uses
  slightly lighter color.
* hyperlink from-file-range to starting line of from-file, if file
  was not created.
* hyperlink to-file-range to starting line of to-file, if file
  was not deleted.
Links are of invisible variety (and "list" class).

Signed-off-by: Jakub Narebski <jnareb@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

gitweb/gitweb.css

@@ -334,11 +334,13 @@ div.diff.extended_header {
 	padding: 2px 0px 2px 0px;
 }
 
+div.diff a.list,
 div.diff a.path,
 div.diff a.hash {
 	text-decoration: none;
 }
 
+div.diff a.list:hover,
 div.diff a.path:hover,
 div.diff a.hash:hover {
 	text-decoration: underline;
@@ -362,14 +364,25 @@ div.diff.rem {
 	color: #cc0000;
 }
 
+div.diff.chunk_header a,
 div.diff.chunk_header {
 	color: #990099;
+}
 
+div.diff.chunk_header {
 	border: dotted #ffe0ff;
 	border-width: 1px 0px 0px 0px;
 	margin-top: 2px;
 }
 
+div.diff.chunk_header span.chunk_info {
+	background-color: #ffeeff;
+}
+
+div.diff.chunk_header span.section {
+	color: #aa22aa;
+}
+
 div.diff.incomplete {
 	color: #cccccc;
 }

gitweb/gitweb.perl

@@ -874,8 +874,10 @@ sub format_subject_html {
 	}
 }
 
+# format patch (diff) line (rather not to be used for diff headers)
 sub format_diff_line {
 	my $line = shift;
+	my ($from, $to) = @_;
 	my $char = substr($line, 0, 1);
 	my $diff_class = "";
 
@@ -891,6 +893,25 @@ sub format_diff_line {
 		$diff_class = " incomplete";
 	}
 	$line = untabify($line);
+	if ($from && $to && $line =~ m/^\@{2} /) {
+		my ($from_text, $from_start, $from_lines, $to_text, $to_start, $to_lines, $section) =
+			$line =~ m/^\@{2} (-(\d+)(?:,(\d+))?) (\+(\d+)(?:,(\d+))?) \@{2}(.*)$/;
+
+		$from_lines = 0 unless defined $from_lines;
+		$to_lines   = 0 unless defined $to_lines;
+
+		if ($from->{'href'}) {
+			$from_text = $cgi->a({-href=>"$from->{'href'}#l$from_start",
+			                     -class=>"list"}, $from_text);
+		}
+		if ($to->{'href'}) {
+			$to_text   = $cgi->a({-href=>"$to->{'href'}#l$to_start",
+			                     -class=>"list"}, $to_text);
+		}
+		$line = "<span class=\"chunk_info\">@@ $from_text $to_text @@</span>" .
+		        "<span class=\"section\">" . esc_html($section, -nbsp=>1) . "</span>";
+		return "<div class=\"diff$diff_class\">$line</div>\n";
+	}
 	return "<div class=\"diff$diff_class\">" . esc_html($line, -nbsp=>1) . "</div>\n";
 }
 
@@ -2372,7 +2393,7 @@ sub git_patchset_body {
 
 			next PATCH if ($patch_line =~ m/^diff /);
 
-			print format_diff_line($patch_line);
+			print format_diff_line($patch_line, \%from, \%to);
 		}
 
 	} continue {