Class: Invoca::Utils::Diff

Inherits:
Object
  • Object
show all
Defined in:
lib/invoca/utils/diff.rb

Constant Summary collapse

VERSION = 
0.3

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(a, b) ⇒ Diff

Returns a new instance of Diff.



222
223
224
225
226
227
 
# File 'lib/invoca/utils/diff.rb', line 222

def initialize(a, b)
  @difftype = a.class
  @diffs    = []
  @curdiffs = []
  makediff(a, b)
end

Instance Attribute Details

#diffs ⇒ Object (readonly)

Returns the value of attribute diffs.



220
221
222
 
# File 'lib/invoca/utils/diff.rb', line 220

def diffs
  @diffs
end

#difftype ⇒ Object (readonly)

Returns the value of attribute difftype.



220
221
222
 
# File 'lib/invoca/utils/diff.rb', line 220

def difftype
  @difftype
end

Class Method Details

.compare(arg1, arg2, options = {}) ⇒ Object 



77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
 
# File 'lib/invoca/utils/diff.rb', line 77

def self.compare arg1, arg2, options = {}
  result = ''
  if arg1 != arg2
    if arg1.class == arg2.class || (arg1.is_a?(Hash) && arg2.is_a?(Hash)) || (arg1.is_a?(Array) && arg2.is_a?(Array)) # Hash and Array are equivalent when specialized
      case arg1
      when Array
        diff_obj  = Diff.new(arg1, arg2)
        summary   = diff_obj.summary
        curr_diff = nil
        (arg1 + [nil]).each_with_index do |arg, index|
          if curr_diff.nil? || index > curr_diff[1].last
            curr_diff = summary.shift
          end
          unless curr_diff && (curr_diff[1].first..curr_diff[1].last) === index
            result += "  #{format arg}\n" unless arg.nil? || options[:short_description]
          end
          if curr_diff && curr_diff[1].first == index
            verb, _a_range, _b_range, del, add = curr_diff
            result +=
              case verb
              when 'd'
                del.map { |t| "- #{format t}\n" }.join
              when 'a'
                add.map { |t| "+ #{format t}\n" }.join +
                  (arg.nil? ? '' : "  #{format arg}\n")
              when 'c'
                del.map_with_index { |t, del_index| "- #{format t}\n#{nested_compare(del, add, del_index)}" }.join +
                  add.map { |t| "+ #{format t}\n" }.join
              end
          end
        end
        summary.empty? or raise "Summary left: #{summary.inspect}"
      when Hash
        arg1.each do |key, value|
          if arg2.has_key? key
            result += "[#{key.inspect}] #{compare value, arg2[key]};\n" if value != arg2[key]
          else
            result += "[#{key.inspect}] expected #{value.inspect}, was missing;\n"
          end
        end
        (arg2.keys - arg1.keys).each do |key|
          result += "[#{key.inspect}] not expected, was #{arg2[key].inspect};\n"
        end
      else
        result = "expected #{arg1.inspect}, was #{arg2.inspect} "
      end
    elsif arg1.class.in?([Float, BigDecimal]) && arg2.class.in?([Float, BigDecimal])
      result = "expected #{arg1.class}: #{arg1.to_s}, was #{arg2.class}: #{arg2.to_s} "
    else
      result = "expected #{arg1.class}:#{arg1.inspect}, was #{arg2.class}:#{arg2.inspect} "
    end
  end
  result
end

.format(value) ⇒ Object 



73
74
75
 
# File 'lib/invoca/utils/diff.rb', line 73

def self.format(value)
  value.is_a?(Numeric) || value.is_a?(String) ? value : value.inspect
end

.lcs(a, b) ⇒ Object 



11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
 
# File 'lib/invoca/utils/diff.rb', line 11

def self.lcs(a, b)
  astart  = 0
  bstart  = 0
  afinish = a.length - 1
  bfinish = b.length - 1
  lcs     = []

  # First we prune off any common elements at the beginning
  while (astart <= afinish && bstart <= afinish && a[astart] == b[bstart])
    lcs[astart] = bstart
    astart      += 1
    bstart      += 1
  end

  # now the end
  while (astart <= afinish && bstart <= bfinish && a[afinish] == b[bfinish])
    lcs[afinish] = bfinish
    afinish      -= 1
    bfinish      -= 1
  end

  bmatches = reverse_hash(b, bstart..bfinish)
  thresh   = []
  links    = []

  (astart..afinish).each { |aindex|
    aelem = a[aindex]
    next unless bmatches.has_key? aelem
    k = nil
    bmatches[aelem].reverse.each { |bindex|
      if k && (thresh[k] > bindex) && (thresh[k - 1] < bindex)
        thresh[k] = bindex
      else
        k = replacenextlarger(thresh, bindex, k)
      end
      links[k] = [(k == 0) ? nil : links[k - 1], aindex, bindex] if k
    }
  }

  if !thresh.empty?
    link = links[thresh.length - 1]
    while link
      lcs[link[1]] = link[2]
      link         = link[0]
    end
  end

  return lcs
end

.nested_compare(subtractions, additions, index) ⇒ Object 



61
62
63
64
65
66
67
68
69
70
71
 
# File 'lib/invoca/utils/diff.rb', line 61

def self.nested_compare(subtractions, additions, index)
  subtraction = subtractions[index]
  addition    = additions[index]
  if subtraction.is_a?(Array) && addition.is_a?(Array)
    return "Nested array diff:\n#{ compare(subtraction, addition) }\n"
  elsif subtraction.is_a?(Hash) && addition.is_a?(Hash)
    return "Nested hash diff:\n#{ compare(subtraction, addition) }\n"
  else
    ""
  end
end

.patch(lhs, diff) ⇒ Object 



290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
 
# File 'lib/invoca/utils/diff.rb', line 290

def self.patch(lhs, diff)
  newary = nil
  if diff.difftype == String
    newary = diff.difftype.new('')
  else
    newary = diff.difftype.new
  end
  ai = 0
  bi = 0
  diff.diffs.each { |d|
    d.each { |mod|
      case mod[0]
      when '-'
        while ai < mod[1]
          newary << lhs[ai]
          ai += 1
          bi += 1
        end
        ai += 1
      when '+'
        while bi < mod[1]
          newary << lhs[ai]
          ai += 1
          bi += 1
        end
        newary << mod[2]
        bi += 1
      else
        raise "Unknown diff action"
      end
    }
  }
  while ai < lhs.length
    newary << lhs[ai]
    ai += 1
    bi += 1
  end
  return newary
end

.replacenextlarger(lhs, value, high = nil) ⇒ Object 



263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
 
# File 'lib/invoca/utils/diff.rb', line 263

def self.replacenextlarger(lhs, value, high = nil)
  high ||= lhs.length
  if lhs.empty? || value > lhs[-1]
    lhs.push value
    return high
  end
  # binary search for replacement point
  low = 0
  while low < high
    index = (high + low) / 2
    found = lhs[index]
    return nil if value == found
    if value > found
      low = index + 1
    else
      high = index
    end
  end

  lhs[low] = value
  # $stderr << "replace #{value} : 0/#{low}/#{init_high} (#{steps} steps) (#{init_high-low} off )\n"
  # $stderr.puts lhs.inspect
  #gets
  #p length - low
  return low
end

.reverse_hash(lhs, range = nil) ⇒ Object

Create a hash that maps elements of the array to arrays of indices where the elements are found.



249
250
251
252
253
254
255
256
257
258
259
260
261
 
# File 'lib/invoca/utils/diff.rb', line 249

def self.reverse_hash(lhs, range = nil)
  range  ||= (0...lhs.length)
  revmap = {}
  range.each { |i|
    elem = lhs[i]
    if revmap.has_key? elem
      revmap[elem].push i
    else
      revmap[elem] = [i]
    end
  }
  return revmap
end

Instance Method Details

#compact ⇒ Object 



185
186
187
188
189
 
# File 'lib/invoca/utils/diff.rb', line 185

def compact
  result = self.dup
  result.compact!
  result
end

#compact! ⇒ Object 



160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
 
# File 'lib/invoca/utils/diff.rb', line 160

def compact!
  diffs = []
  @diffs.each do |diff|
    puts "compacting #{diff.inspect}"
    i       = 0
    curdiff = []
    while i < diff.length
      action = diff[i][0]
      s      = @difftype.is_a?(String) ? diff[i][2, 1] : [diff[i][2]]
      offset = diff[i][1]
      last   = offset
      i      += 1
      while diff[i] && diff[i][0] == action && diff[i][1] == last + 1
        s << diff[i][2]
        last = diff[i][1]
        i    += 1
      end
      curdiff.push [action, offset, s]
    end
    diffs.push curdiff
  end
  @diffs = diffs
  self
end

#discarda(i, elem) ⇒ Object 



234
235
236
 
# File 'lib/invoca/utils/diff.rb', line 234

def discarda(i, elem)
  @curdiffs.push ['-', i, elem]
end

#discardb(i, elem) ⇒ Object 



238
239
240
 
# File 'lib/invoca/utils/diff.rb', line 238

def discardb(i, elem)
  @curdiffs.push ['+', i, elem]
end

#inspect ⇒ Object 



242
243
244
 
# File 'lib/invoca/utils/diff.rb', line 242

def inspect
  @diffs.inspect
end

#makediff(a, b) ⇒ Object 



133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
 
# File 'lib/invoca/utils/diff.rb', line 133

def makediff(a, b)
  lcs = self.class.lcs(a, b)
  ai  = bi = 0
  while ai < lcs.length
    if lcs[ai]
      while bi < lcs[ai]
        discardb(bi, b[bi])
        bi += 1
      end
      match
      bi += 1
    else
      discarda(ai, a[ai])
    end
    ai += 1
  end
  while ai < a.length
    discarda(ai, a[ai])
    ai += 1
  end
  while bi < b.length
    discardb(bi, b[bi])
    bi += 1
  end
  match
end

#match ⇒ Object 



229
230
231
232
 
# File 'lib/invoca/utils/diff.rb', line 229

def match
  @diffs << @curdiffs unless @curdiffs.empty?
  @curdiffs = []
end

#summary ⇒ Object 



191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
 
# File 'lib/invoca/utils/diff.rb', line 191

def summary
  result   = []
  b_offset = 0
  @diffs.each do |block|
    del = []
    add = []
    block.each do |diff|
      case diff[0]
      when "-"
        del << diff[2]
      when "+"
        add << diff[2]
      end
    end
    first                  = block[0][1]
    verb, a_range, b_range =
      if del.empty?
        ['a', [first - b_offset, first - b_offset], [first, first + add.size - 1]]
      elsif add.empty?
        ['d', [first, first + del.size - 1], [first + b_offset, first + b_offset]]
      else
        ['c', [first, first + del.size - 1], [first + b_offset, first + b_offset + add.size - 1]]
      end
    b_offset               = b_offset + add.size - del.size
    result << [verb, a_range, b_range, del, add]
  end
  result
end