No activity since 2012, no tests, no chance of ever graduating. Cc: Jeff King <peff@xxxxxxxx> Signed-off-by: Felipe Contreras <felipe.contreras@xxxxxxxxx> --- contrib/diff-highlight/README | 152 ----------------------------- contrib/diff-highlight/diff-highlight | 173 ---------------------------------- 2 files changed, 325 deletions(-) delete mode 100644 contrib/diff-highlight/README delete mode 100755 contrib/diff-highlight/diff-highlight diff --git a/contrib/diff-highlight/README b/contrib/diff-highlight/README deleted file mode 100644 index 502e03b..0000000 --- a/contrib/diff-highlight/README +++ /dev/null @@ -1,152 +0,0 @@ -diff-highlight -============== - -Line oriented diffs are great for reviewing code, because for most -hunks, you want to see the old and the new segments of code next to each -other. Sometimes, though, when an old line and a new line are very -similar, it's hard to immediately see the difference. - -You can use "--color-words" to highlight only the changed portions of -lines. However, this can often be hard to read for code, as it loses -the line structure, and you end up with oddly formatted bits. - -Instead, this script post-processes the line-oriented diff, finds pairs -of lines, and highlights the differing segments. It's currently very -simple and stupid about doing these tasks. In particular: - - 1. It will only highlight hunks in which the number of removed and - added lines is the same, and it will pair lines within the hunk by - position (so the first removed line is compared to the first added - line, and so forth). This is simple and tends to work well in - practice. More complex changes don't highlight well, so we tend to - exclude them due to the "same number of removed and added lines" - restriction. Or even if we do try to highlight them, they end up - not highlighting because of our "don't highlight if the whole line - would be highlighted" rule. - - 2. It will find the common prefix and suffix of two lines, and - consider everything in the middle to be "different". It could - instead do a real diff of the characters between the two lines and - find common subsequences. However, the point of the highlight is to - call attention to a certain area. Even if some small subset of the - highlighted area actually didn't change, that's OK. In practice it - ends up being more readable to just have a single blob on the line - showing the interesting bit. - -The goal of the script is therefore not to be exact about highlighting -changes, but to call attention to areas of interest without being -visually distracting. Non-diff lines and existing diff coloration is -preserved; the intent is that the output should look exactly the same as -the input, except for the occasional highlight. - -Use ---- - -You can try out the diff-highlight program with: - ---------------------------------------------- -git log -p --color | /path/to/diff-highlight ---------------------------------------------- - -If you want to use it all the time, drop it in your $PATH and put the -following in your git configuration: - ---------------------------------------------- -[pager] - log = diff-highlight | less - show = diff-highlight | less - diff = diff-highlight | less ---------------------------------------------- - -Bugs ----- - -Because diff-highlight relies on heuristics to guess which parts of -changes are important, there are some cases where the highlighting is -more distracting than useful. Fortunately, these cases are rare in -practice, and when they do occur, the worst case is simply a little -extra highlighting. This section documents some cases known to be -sub-optimal, in case somebody feels like working on improving the -heuristics. - -1. Two changes on the same line get highlighted in a blob. For example, - highlighting: - ----------------------------------------------- --foo(buf, size); -+foo(obj->buf, obj->size); ----------------------------------------------- - - yields (where the inside of "+{}" would be highlighted): - ----------------------------------------------- --foo(buf, size); -+foo(+{obj->buf, obj->}size); ----------------------------------------------- - - whereas a more semantically meaningful output would be: - ----------------------------------------------- --foo(buf, size); -+foo(+{obj->}buf, +{obj->}size); ----------------------------------------------- - - Note that doing this right would probably involve a set of - content-specific boundary patterns, similar to word-diff. Otherwise - you get junk like: - ------------------------------------------------------ --this line has some -{i}nt-{ere}sti-{ng} text on it -+this line has some +{fa}nt+{a}sti+{c} text on it ------------------------------------------------------ - - which is less readable than the current output. - -2. The multi-line matching assumes that lines in the pre- and post-image - match by position. This is often the case, but can be fooled when a - line is removed from the top and a new one added at the bottom (or - vice versa). Unless the lines in the middle are also changed, diffs - will show this as two hunks, and it will not get highlighted at all - (which is good). But if the lines in the middle are changed, the - highlighting can be misleading. Here's a pathological case: - ------------------------------------------------------ --one --two --three --four -+two 2 -+three 3 -+four 4 -+five 5 ------------------------------------------------------ - - which gets highlighted as: - ------------------------------------------------------ --one --t-{wo} --three --f-{our} -+two 2 -+t+{hree 3} -+four 4 -+f+{ive 5} ------------------------------------------------------ - - because it matches "two" to "three 3", and so forth. It would be - nicer as: - ------------------------------------------------------ --one --two --three --four -+two +{2} -+three +{3} -+four +{4} -+five 5 ------------------------------------------------------ - - which would probably involve pre-matching the lines into pairs - according to some heuristic. diff --git a/contrib/diff-highlight/diff-highlight b/contrib/diff-highlight/diff-highlight deleted file mode 100755 index c4404d4..0000000 --- a/contrib/diff-highlight/diff-highlight +++ /dev/null @@ -1,173 +0,0 @@ -#!/usr/bin/perl - -use warnings FATAL => 'all'; -use strict; - -# Highlight by reversing foreground and background. You could do -# other things like bold or underline if you prefer. -my $HIGHLIGHT = "\x1b[7m"; -my $UNHIGHLIGHT = "\x1b[27m"; -my $COLOR = qr/\x1b\[[0-9;]*m/; -my $BORING = qr/$COLOR|\s/; - -my @removed; -my @added; -my $in_hunk; - -while (<>) { - if (!$in_hunk) { - print; - $in_hunk = /^$COLOR*\@/; - } - elsif (/^$COLOR*-/) { - push @removed, $_; - } - elsif (/^$COLOR*\+/) { - push @added, $_; - } - else { - show_hunk(\@removed, \@added); - @removed = (); - @added = (); - - print; - $in_hunk = /^$COLOR*[\@ ]/; - } - - # Most of the time there is enough output to keep things streaming, - # but for something like "git log -Sfoo", you can get one early - # commit and then many seconds of nothing. We want to show - # that one commit as soon as possible. - # - # Since we can receive arbitrary input, there's no optimal - # place to flush. Flushing on a blank line is a heuristic that - # happens to match git-log output. - if (!length) { - local $| = 1; - } -} - -# Flush any queued hunk (this can happen when there is no trailing context in -# the final diff of the input). -show_hunk(\@removed, \@added); - -exit 0; - -sub show_hunk { - my ($a, $b) = @_; - - # If one side is empty, then there is nothing to compare or highlight. - if (!@$a || !@$b) { - print @$a, @$b; - return; - } - - # If we have mismatched numbers of lines on each side, we could try to - # be clever and match up similar lines. But for now we are simple and - # stupid, and only handle multi-line hunks that remove and add the same - # number of lines. - if (@$a != @$b) { - print @$a, @$b; - return; - } - - my @queue; - for (my $i = 0; $i < @$a; $i++) { - my ($rm, $add) = highlight_pair($a->[$i], $b->[$i]); - print $rm; - push @queue, $add; - } - print @queue; -} - -sub highlight_pair { - my @a = split_line(shift); - my @b = split_line(shift); - - # Find common prefix, taking care to skip any ansi - # color codes. - my $seen_plusminus; - my ($pa, $pb) = (0, 0); - while ($pa < @a && $pb < @b) { - if ($a[$pa] =~ /$COLOR/) { - $pa++; - } - elsif ($b[$pb] =~ /$COLOR/) { - $pb++; - } - elsif ($a[$pa] eq $b[$pb]) { - $pa++; - $pb++; - } - elsif (!$seen_plusminus && $a[$pa] eq '-' && $b[$pb] eq '+') { - $seen_plusminus = 1; - $pa++; - $pb++; - } - else { - last; - } - } - - # Find common suffix, ignoring colors. - my ($sa, $sb) = ($#a, $#b); - while ($sa >= $pa && $sb >= $pb) { - if ($a[$sa] =~ /$COLOR/) { - $sa--; - } - elsif ($b[$sb] =~ /$COLOR/) { - $sb--; - } - elsif ($a[$sa] eq $b[$sb]) { - $sa--; - $sb--; - } - else { - last; - } - } - - if (is_pair_interesting(\@a, $pa, $sa, \@b, $pb, $sb)) { - return highlight_line(\@a, $pa, $sa), - highlight_line(\@b, $pb, $sb); - } - else { - return join('', @a), - join('', @b); - } -} - -sub split_line { - local $_ = shift; - return map { /$COLOR/ ? $_ : (split //) } - split /($COLOR*)/; -} - -sub highlight_line { - my ($line, $prefix, $suffix) = @_; - - return join('', - @{$line}[0..($prefix-1)], - $HIGHLIGHT, - @{$line}[$prefix..$suffix], - $UNHIGHLIGHT, - @{$line}[($suffix+1)..$#$line] - ); -} - -# Pairs are interesting to highlight only if we are going to end up -# highlighting a subset (i.e., not the whole line). Otherwise, the highlighting -# is just useless noise. We can detect this by finding either a matching prefix -# or suffix (disregarding boring bits like whitespace and colorization). -sub is_pair_interesting { - my ($a, $pa, $sa, $b, $pb, $sb) = @_; - my $prefix_a = join('', @$a[0..($pa-1)]); - my $prefix_b = join('', @$b[0..($pb-1)]); - my $suffix_a = join('', @$a[($sa+1)..$#$a]); - my $suffix_b = join('', @$b[($sb+1)..$#$b]); - - return $prefix_a !~ /^$COLOR*-$BORING*$/ || - $prefix_b !~ /^$COLOR*\+$BORING*$/ || - $suffix_a !~ /^$BORING*$/ || - $suffix_b !~ /^$BORING*$/; -} -- 1.9.2+fc1.27.gbce2056 -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html