Files
danbooru/app/logical/diff_builder.rb
evazion c2688e3aff Fix #4263: Wiki page differences use the wrong order.
Standardize DiffBuilder to treat the first argument as the new item and
the second argument as the old item. This is the order used in most
other places.
2020-01-21 00:09:38 -06:00

58 lines
1.7 KiB
Ruby

class DiffBuilder
attr_reader :this_text, :that_text, :pattern
def initialize(this_text, that_text, pattern)
@this_text = this_text
@that_text = that_text
@pattern = pattern
end
def build
thisarr = this_text.scan(pattern)
otharr = that_text.scan(pattern)
cbo = Diff::LCS::ContextDiffCallbacks.new
diffs = otharr.diff(thisarr, cbo)
escape_html = ->(str) {str.gsub(/&/, '&amp;').gsub(/</, '&lt;').gsub(/>/, '&gt;')}
output = thisarr
output.each { |q| q.replace(escape_html[q]) }
diffs.reverse_each do |hunk|
newchange = hunk.max {|a, b| a.old_position <=> b.old_position}
newstart = newchange.old_position
oldstart = hunk.min {|a, b| a.old_position <=> b.old_position}.old_position
if newchange.action == '+'
output.insert(newstart, '</ins>')
end
hunk.reverse_each do |chg|
case chg.action
when '-'
oldstart = chg.old_position
output[chg.old_position] = '<span class="paragraph-mark">¶</span><br>' if chg.old_element.match(/^\r?\n$/)
when '+'
if chg.new_element.match(/^\r?\n$/)
output.insert(chg.old_position, '<span class="paragraph-mark">¶</span><br>')
else
output.insert(chg.old_position, (escape_html[chg.new_element]).to_s)
end
end
end
if newchange.action == '+'
output.insert(newstart, '<ins>')
end
if hunk[0].action == '-'
output.insert((newstart == oldstart || newchange.action != '+') ? newstart + 1 : newstart, '</del>')
output.insert(oldstart, '<del>')
end
end
output.join.gsub(/\r?\n/, '<span class="paragraph-mark">¶</span><br>').html_safe
end
end