gitweb: Highlight interesting parts of diff
Reading diff output is sometimes very hard, even if it's colored, especially if lines differ only in few characters. This is often true when a commit fixes a typo or renames some variables or functions. This commit teaches gitweb to highlight characters that are different between old and new line with a light green/red background. This should work in the similar manner as in Trac or GitHub. The algorithm that compares lines is based on contrib/diff-highlight. Basically, it works by determining common prefix/suffix of corresponding lines and highlightning only the middle part of lines. For more information, see contrib/diff-highlight/README. Combined diffs are not supported but a following commit will change it. Since we need to pass esc_html()'ed or esc_html_hl_regions()'ed lines to format_diff_lines(), so it was taught to accept preformatted lines passed as a reference. Signed-off-by: Michał Kiedrowicz <michal.kiedrowicz@gmail.com> Acked-by: Jakub Narębski <jnareb@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Michał Kiedrowicz committed
Apr 11, 2012 at 23:18 UTC
5fb6ddf67afb3d0dc9b1fce64543f20b28a81b4b
2 files changed
+103
-12
gitweb/gitweb.perl
+95
-12
@@ -2430,19 +2430,25 @@ sub format_cc_diff_chunk_header {
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}
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# process patch (diff) line (not to be used for diff headers),
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-# returning HTML-formatted (but not wrapped) line
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+# returning HTML-formatted (but not wrapped) line.
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+# If the line is passed as a reference, it is treated as HTML and not
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+# esc_html()'ed.
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sub format_diff_line {
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my ($line, $diff_class, $from, $to) = @_;
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- chomp $line;
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- $line = untabify($line);
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-
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- if ($from && $to && $line =~ m/^\@{2} /) {
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- $line = format_unidiff_chunk_header($line, $from, $to);
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- } elsif ($from && $to && $line =~ m/^\@{3}/) {
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- $line = format_cc_diff_chunk_header($line, $from, $to);
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+ if (ref($line)) {
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+ $line = $$line;
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} else {
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- $line = esc_html($line, -nbsp=>1);
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+ chomp $line;
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+ $line = untabify($line);
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+
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+ if ($from && $to && $line =~ m/^\@{2} /) {
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+ $line = format_unidiff_chunk_header($line, $from, $to);
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+ } elsif ($from && $to && $line =~ m/^\@{3}/) {
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+ $line = format_cc_diff_chunk_header($line, $from, $to);
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+ } else {
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+ $line = esc_html($line, -nbsp=>1);
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+ }
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}
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my $diff_classes = "diff";
@@ -5055,10 +5061,89 @@ sub print_inline_diff_lines {
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print @$ctx, @$rem, @$add;
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}
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+# Format removed and added line, mark changed part and HTML-format them.
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+# Implementation is based on contrib/diff-highlight
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+sub format_rem_add_lines_pair {
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+ my ($rem, $add) = @_;
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+
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+ # We need to untabify lines before split()'ing them;
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+ # otherwise offsets would be invalid.
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+ chomp $rem;
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+ chomp $add;
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+ $rem = untabify($rem);
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+ $add = untabify($add);
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+
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+ my @rem = split(//, $rem);
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+ my @add = split(//, $add);
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+ my ($esc_rem, $esc_add);
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+ # Ignore +/- character, thus $prefix_len is set to 1.
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+ my ($prefix_len, $suffix_len) = (1, 0);
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+ my ($prefix_has_nonspace, $suffix_has_nonspace);
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+
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+ my $shorter = (@rem < @add) ? @rem : @add;
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+ while ($prefix_len < $shorter) {
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+ last if ($rem[$prefix_len] ne $add[$prefix_len]);
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+
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+ $prefix_has_nonspace = 1 if ($rem[$prefix_len] !~ /\s/);
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+ $prefix_len++;
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+ }
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+
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+ while ($prefix_len + $suffix_len < $shorter) {
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+ last if ($rem[-1 - $suffix_len] ne $add[-1 - $suffix_len]);
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+
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+ $suffix_has_nonspace = 1 if ($rem[-1 - $suffix_len] !~ /\s/);
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+ $suffix_len++;
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+ }
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+
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+ # Mark lines that are different from each other, but have some common
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+ # part that isn't whitespace. If lines are completely different, don't
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+ # mark them because that would make output unreadable, especially if
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+ # diff consists of multiple lines.
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+ if ($prefix_has_nonspace || $suffix_has_nonspace) {
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+ $esc_rem = esc_html_hl_regions($rem, 'marked',
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+ [$prefix_len, @rem - $suffix_len], -nbsp=>1);
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+ $esc_add = esc_html_hl_regions($add, 'marked',
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+ [$prefix_len, @add - $suffix_len], -nbsp=>1);
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+ } else {
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+ $esc_rem = esc_html($rem, -nbsp=>1);
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+ $esc_add = esc_html($add, -nbsp=>1);
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+ }
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+
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+ return format_diff_line(\$esc_rem, 'rem'),
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+ format_diff_line(\$esc_add, 'add');
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+}
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+
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+# HTML-format diff context, removed and added lines.
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+sub format_ctx_rem_add_lines {
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+ my ($ctx, $rem, $add, $is_combined) = @_;
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+ my (@new_ctx, @new_rem, @new_add);
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+
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+ # Highlight if every removed line has a corresponding added line.
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+ # Combined diffs are not supported at this moment.
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+ if (!$is_combined && @$add > 0 && @$add == @$rem) {
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+ for (my $i = 0; $i < @$add; $i++) {
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+ my ($line_rem, $line_add) = format_rem_add_lines_pair(
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+ $rem->[$i], $add->[$i]);
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+ push @new_rem, $line_rem;
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+ push @new_add, $line_add;
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+ }
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+ } else {
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+ @new_rem = map { format_diff_line($_, 'rem') } @$rem;
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+ @new_add = map { format_diff_line($_, 'add') } @$add;
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+ }
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+
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+ @new_ctx = map { format_diff_line($_, 'ctx') } @$ctx;
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+
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+ return (\@new_ctx, \@new_rem, \@new_add);
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+}
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+
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# Print context lines and then rem/add lines.
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sub print_diff_lines {
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my ($ctx, $rem, $add, $diff_style, $is_combined) = @_;
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+ ($ctx, $rem, $add) = format_ctx_rem_add_lines($ctx, $rem, $add,
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+ $is_combined);
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+
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if ($diff_style eq 'sidebyside' && !$is_combined) {
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print_sidebyside_diff_lines($ctx, $rem, $add);
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} else {
@@ -5090,11 +5175,9 @@ sub print_diff_chunk {
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foreach my $line_info (@chunk) {
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my ($class, $line) = @$line_info;
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- $line = format_diff_line($line, $class, $from, $to);
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-
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# print chunk headers
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if ($class && $class eq 'chunk_header') {
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- print $line;
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+ print format_diff_line($line, $class, $from, $to);
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next;
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}
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gitweb/static/gitweb.css
+8
@@ -438,6 +438,10 @@ div.diff.add {
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color: #008800;
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}
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+div.diff.add span.marked {
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+ background-color: #aaffaa;
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+}
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+
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div.diff.from_file a.path,
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div.diff.from_file {
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color: #aa0000;
@@ -447,6 +451,10 @@ div.diff.rem {
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color: #cc0000;
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}
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+div.diff.rem span.marked {
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+ background-color: #ffaaaa;
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+}
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+
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div.diff.chunk_header a,
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div.diff.chunk_header {
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color: #990099;