1begin
2 require 'rubygems'
3 require 'diff/lcs' #necessary due to loading bug on some machines - not sure why - DaC
4 require 'diff/lcs/hunk'
5rescue LoadError ; raise "You must gem install diff-lcs to use diffing" ; end
6
7require 'pp'
8
9module Spec
10 module Expectations
11 module Differs
12
13 # TODO add some rdoc
14 class Default
15 def initialize(options)
16 @options = options
17 end
18
19 # This is snagged from diff/lcs/ldiff.rb (which is a commandline tool)
20 def diff_as_string(data_old, data_new)
21 data_old = data_old.split(/\n/).map! { |e| e.chomp }
22 data_new = data_new.split(/\n/).map! { |e| e.chomp }
23 output = ""
24 diffs = Diff::LCS.diff(data_old, data_new)
25 return output if diffs.empty?
26 oldhunk = hunk = nil
27 file_length_difference = 0
28 diffs.each do |piece|
29 begin
30 hunk = Diff::LCS::Hunk.new(data_old, data_new, piece, context_lines,
31 file_length_difference)
32 file_length_difference = hunk.file_length_difference
33 next unless oldhunk
34 # Hunks may overlap, which is why we need to be careful when our
35 # diff includes lines of context. Otherwise, we might print
36 # redundant lines.
37 if (context_lines > 0) and hunk.overlaps?(oldhunk)
38 hunk.unshift(oldhunk)
39 else
40 output << oldhunk.diff(format)
41 end
42 ensure
43 oldhunk = hunk
44 output << "\n"
45 end
46 end
47 #Handle the last remaining hunk
48 output << oldhunk.diff(format) << "\n"
49 end
50
51 def diff_as_object(target,expected)
52 diff_as_string(PP.pp(target,""), PP.pp(expected,""))
53 end
54
55 protected
56 def format
57 @options.diff_format
58 end
59
60 def context_lines
61 @options.context_lines
62 end
63 end
64 end
65 end
66end