gitweb: Add a feature to show side-by-side diff

This commits adds to support for showing "side-by-side" style diff.
Currently you have to hand-craft the URL; navigation for selecting
diff style is to be added in the next commit.

The diff output in unified format from "git diff-tree" is reorganized to
side-by-side style chunk by chunk with format_sidebyside_diff_chunk().
This reorganization requires knowledge about diff line classification,
so format_diff_line() was renamed to process_diff_line(), and changed to
return tuple (list) consisting of class of diff line and of
HTML-formatted (but not wrapped in <div class="diff ...">...</div>) diff
line.  Wrapping is now done by caller, i.e. git_patchset_body().

Gitweb uses float+margin CSS-based layout for "side by side" diff.

You can specify style of diff with "ds" ('diff_style') query
parameter.  Currently supported values are 'inline' and 'sidebyside';
the default is 'inline'.

Another solution would be to use "opt" ('extra_options') for that...
though current use of it in gitweb seems to suggest that "opt" is more
about passing extra options to underlying git commands, and "git diff"
doesn't support '--side-by-side' like GNU diff does, (yet?).

Signed-off-by: Kato Kazuyoshi <kato.kazuyoshi@gmail.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 95d278acc84ba7ff698493ab6a495673a236f735..68629f66c952f85e0294cfa9406d7d0b927eb3a2 100755 (executable)
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -759,6 +759,7 @@ our @cgi_param_mapping = (
        extra_options => "opt",
        search_use_regexp => "sr",
        ctag => "by_tag",
+       diff_style => "ds",
        # this must be last entry (for manipulation from JavaScript)
        javascript => "js"
 );
@@ -2317,28 +2318,27 @@ sub format_cc_diff_chunk_header {
        return $line;
 }
 
-# format patch (diff) line (not to be used for diff headers)
-sub format_diff_line {
+# process patch (diff) line (not to be used for diff headers),
+# returning class and HTML-formatted (but not wrapped) line
+sub process_diff_line {
        my $line = shift;
        my ($from, $to) = @_;
 
        my $diff_class = diff_line_class($line, $from, $to);
-       my $diff_classes = "diff";
-       $diff_classes .= " $diff_class" if ($diff_class);
 
        chomp $line;
        $line = untabify($line);
 
        if ($from && $to && $line =~ m/^\@{2} /) {
                $line = format_unidiff_chunk_header($line, $from, $to);
-               return "<div class=\"$diff_classes\">$line</div>\n";
+               return $diff_class, $line;
 
        } elsif ($from && $to && $line =~ m/^\@{3}/) {
                $line = format_cc_diff_chunk_header($line, $from, $to);
-               return "<div class=\"$diff_classes\">$line</div>\n";
+               return $diff_class, $line;
 
        }
-       return "<div class=\"$diff_classes\">" . esc_html($line, -nbsp=>1) . "</div>\n";
+       return $diff_class, esc_html($line, -nbsp=>1);
 }
 
 # Generates undef or something like "_snapshot_" or "snapshot (_tbz2_ _zip_)",
@@ -4860,8 +4860,78 @@ sub git_difftree_body {
        print "</table>\n";
 }
 
+sub print_sidebyside_diff_chunk {
+       my @chunk = @_;
+       my (@ctx, @rem, @add);
+
+       return unless @chunk;
+
+       # incomplete last line might be among removed or added lines,
+       # or both, or among context lines: find which
+       for (my $i = 1; $i < @chunk; $i++) {
+               if ($chunk[$i][0] eq 'incomplete') {
+                       $chunk[$i][0] = $chunk[$i-1][0];
+               }
+       }
+
+       # guardian
+       push @chunk, ["", ""];
+
+       foreach my $line_info (@chunk) {
+               my ($class, $line) = @$line_info;
+
+               # print chunk headers
+               if ($class && $class eq 'chunk_header') {
+                       print $line;
+                       next;
+               }
+
+               ## print from accumulator when type of class of lines change
+               # empty contents block on start rem/add block, or end of chunk
+               if (@ctx && (!$class || $class eq 'rem' || $class eq 'add')) {
+                       print join '',
+                               '<div class="chunk_block">',
+                                       '<div class="old">',
+                                       @ctx,
+                                       '</div>',
+                                       '<div class="new">',
+                                       @ctx,
+                                       '</div>',
+                               '</div>';
+                       @ctx = ();
+               }
+               # empty add/rem block on start context block, or end of chunk
+               if ((@rem || @add) && (!$class || $class eq 'ctx')) {
+                       print join '',
+                               '<div class="chunk_block">',
+                                       '<div class="old">',
+                                       @rem,
+                                       '</div>',
+                                       '<div class="new">',
+                                       @add,
+                                       '</div>',
+                               '</div>';
+                       @rem = @add = ();
+               }
+
+               ## adding lines to accumulator
+               # guardian value
+               last unless $line;
+               # rem, add or change
+               if ($class eq 'rem') {
+                       push @rem, $line;
+               } elsif ($class eq 'add') {
+                       push @add, $line;
+               }
+               # context line
+               if ($class eq 'ctx') {
+                       push @ctx, $line;
+               }
+       }
+}
+
 sub git_patchset_body {
-       my ($fd, $difftree, $hash, @hash_parents) = @_;
+       my ($fd, $diff_style, $difftree, $hash, @hash_parents) = @_;
        my ($hash_parent) = $hash_parents[0];
 
        my $is_combined = (@hash_parents > 1);
@@ -4871,6 +4941,7 @@ sub git_patchset_body {
        my $diffinfo;
        my $to_name;
        my (%from, %to);
+       my @chunk; # for side-by-side diff
 
        print "<div class=\"patchset\">\n";
 
@@ -4977,10 +5048,29 @@ sub git_patchset_body {
 
                        next PATCH if ($patch_line =~ m/^diff /);
 
-                       print format_diff_line($patch_line, \%from, \%to);
+                       my ($class, $line) = process_diff_line($patch_line, \%from, \%to);
+                       my $diff_classes = "diff";
+                       $diff_classes .= " $class" if ($class);
+                       $line = "<div class=\"$diff_classes\">$line</div>\n";
+
+                       if ($diff_style eq 'sidebyside' && !$is_combined) {
+                               if ($class eq 'chunk_header') {
+                                       print_sidebyside_diff_chunk(@chunk);
+                                       @chunk = ( [ $class, $line ] );
+                               } else {
+                                       push @chunk, [ $class, $line ];
+                               }
+                       } else {
+                               # default 'inline' style and unknown styles
+                               print $line;
+                       }
                }
 
        } continue {
+               if (@chunk) {
+                       print_sidebyside_diff_chunk(@chunk);
+                       @chunk = ();
+               }
                print "</div>\n"; # class="patch"
        }
 
@@ -6976,6 +7066,7 @@ sub git_object {
 
 sub git_blobdiff {
        my $format = shift || 'html';
+       my $diff_style = $input_params{'diff_style'} || 'inline';
 
        my $fd;
        my @difftree;
@@ -7085,7 +7176,8 @@ sub git_blobdiff {
        if ($format eq 'html') {
                print "<div class=\"page_body\">\n";
 
-               git_patchset_body($fd, [ \%diffinfo ], $hash_base, $hash_parent_base);
+               git_patchset_body($fd, $diff_style,
+                                 [ \%diffinfo ], $hash_base, $hash_parent_base);
                close $fd;
 
                print "</div>\n"; # class="page_body"
@@ -7113,6 +7205,7 @@ sub git_blobdiff_plain {
 sub git_commitdiff {
        my %params = @_;
        my $format = $params{-format} || 'html';
+       my $diff_style = $input_params{'diff_style'} || 'inline';
 
        my ($patch_max) = gitweb_get_feature('patches');
        if ($format eq 'patch') {
@@ -7316,7 +7409,8 @@ sub git_commitdiff {
                                  $use_parents ? @{$co{'parents'}} : $hash_parent);
                print "<br/>\n";
 
-               git_patchset_body($fd, \@difftree, $hash,
+               git_patchset_body($fd, $diff_style,
+                                 \@difftree, $hash,
                                  $use_parents ? @{$co{'parents'}} : $hash_parent);
                close $fd;
                print "</div>\n"; # class="page_body"

diff --git a/gitweb/static/gitweb.css b/gitweb/static/gitweb.css
index 7d88509208417e4b1222629002ea339ecc32526e..21842a66ac33d8f42e3348006a99ef45acdce24e 100644 (file)
--- a/gitweb/static/gitweb.css
+++ b/gitweb/static/gitweb.css
@@ -475,6 +475,23 @@ div.diff.nodifferences {
        color: #600000;
 }
 
+/* side-by-side diff */
+div.chunk_block {
+       overflow: hidden;
+}
+
+div.chunk_block div.old {
+       float: left;
+       width: 50%;
+       overflow: hidden;
+}
+
+div.chunk_block div.new {
+       margin-left: 50%;
+       width: 50%;
+}
+
+
 div.index_include {
        border: solid #d9d8d1;
        border-width: 0px 0px 1px;