gitweb: Refactor diff body line classification

Simplify classification of diff line body in format_diff_line(),
replacing two long if-elsif chains (one for ordinary diff and one for
combined diff of a merge commit) with a single regexp match.  Refactor
this code into diff_line_class() function.

While at it:

* Fix an artifact in that $diff_class included leading space to be
  able to compose classes like this "class=\"diff$diff_class\"', even
  when $diff_class was an empty string.  This made code unnecessary
  ugly: $diff_class is now just class name or an empty string.

* Introduce "ctx" class for context lines ($diff_class was set to ""
  in this case before this commit).

Idea and initial code by Junio C Hamano, polish and testing by Jakub
Narebski.  Inspired by patch adding side-by-side diff by Kato Kazuyoshi,
which required $diff_class to be name of class without extra space.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jakub Narebski <jnareb@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index 4f0c3bd90c7f90dad1674f50999da534c33c0261..914fd4cf6c2f5a9fb61e25c2ce3ab3530794eb08 100755 (executable)
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -2225,40 +2225,47 @@ sub format_diff_cc_simplified {
        return $result;
 }
 
+sub diff_line_class {
+       my ($line, $from, $to) = @_;
+
+       # ordinary diff
+       my $num_sign = 1;
+       # combined diff
+       if ($from && $to && ref($from->{'href'}) eq "ARRAY") {
+               $num_sign = scalar @{$from->{'href'}};
+       }
+
+       my @diff_line_classifier = (
+               { regexp => qr/^\@\@{$num_sign} /, class => "chunk_header"},
+               { regexp => qr/^\\/,               class => "incomplete"  },
+               { regexp => qr/^ {$num_sign}/,     class => "ctx" },
+               # classifier for context must come before classifier add/rem,
+               # or we would have to use more complicated regexp, for example
+               # qr/(?= {0,$m}\+)[+ ]{$num_sign}/, where $m = $num_sign - 1;
+               { regexp => qr/^[+ ]{$num_sign}/,   class => "add" },
+               { regexp => qr/^[- ]{$num_sign}/,   class => "rem" },
+       );
+       for my $clsfy (@diff_line_classifier) {
+               return $clsfy->{'class'}
+                       if ($line =~ $clsfy->{'regexp'});
+       }
+
+       # fallback
+       return "";
+}
+
 # format patch (diff) line (not to be used for diff headers)
 sub format_diff_line {
        my $line = shift;
        my ($from, $to) = @_;
-       my $diff_class = "";
 
-       chomp $line;
+       my $diff_class = diff_line_class($line, $from, $to);
+       my $diff_classes = "diff";
+       $diff_classes .= " $diff_class" if ($diff_class);
 
-       if ($from && $to && ref($from->{'href'}) eq "ARRAY") {
-               # combined diff
-               my $prefix = substr($line, 0, scalar @{$from->{'href'}});
-               if ($line =~ m/^\@{3}/) {
-                       $diff_class = " chunk_header";
-               } elsif ($line =~ m/^\\/) {
-                       $diff_class = " incomplete";
-               } elsif ($prefix =~ tr/+/+/) {
-                       $diff_class = " add";
-               } elsif ($prefix =~ tr/-/-/) {
-                       $diff_class = " rem";
-               }
-       } else {
-               # assume ordinary diff
-               my $char = substr($line, 0, 1);
-               if ($char eq '+') {
-                       $diff_class = " add";
-               } elsif ($char eq '-') {
-                       $diff_class = " rem";
-               } elsif ($char eq '@') {
-                       $diff_class = " chunk_header";
-               } elsif ($char eq "\\") {
-                       $diff_class = " incomplete";
-               }
-       }
+       chomp $line;
        $line = untabify($line);
+
        if ($from && $to && $line =~ m/^\@{2} /) {
                my ($from_text, $from_start, $from_lines, $to_text, $to_start, $to_lines, $section) =
                        $line =~ m/^\@{2} (-(\d+)(?:,(\d+))?) (\+(\d+)(?:,(\d+))?) \@{2}(.*)$/;
@@ -2276,7 +2283,7 @@ sub format_diff_line {
                }
                $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=\"$diff_classes\">$line</div>\n";
        } elsif ($from && $to && $line =~ m/^\@{3}/) {
                my ($prefix, $ranges, $section) = $line =~ m/^(\@+) (.*?) \@+(.*)$/;
                my (@from_text, @from_start, @from_nlines, $to_text, $to_start, $to_nlines);
@@ -2309,9 +2316,9 @@ sub format_diff_line {
                }
                $line .= " $prefix</span>" .
                         "<span class=\"section\">" . esc_html($section, -nbsp=>1) . "</span>";
-               return "<div class=\"diff$diff_class\">$line</div>\n";
+               return "<div class=\"$diff_classes\">$line</div>\n";
        }
-       return "<div class=\"diff$diff_class\">" . esc_html($line, -nbsp=>1) . "</div>\n";
+       return "<div class=\"$diff_classes\">" . esc_html($line, -nbsp=>1) . "</div>\n";
 }
 
 # Generates undef or something like "_snapshot_" or "snapshot (_tbz2_ _zip_)",