Module: Diff::LCS::Ldiff

Defined in:
lib/diff/lcs/ldiff.rb

Overview

:nodoc:

Constant Summary collapse

<<-COPYRIGHT
ldiff #{Diff::LCS::VERSION}
Copyright 2004-2019 Austin Ziegler

Part of Diff::LCS.
https://github.com/halostatue/diff-lcs

This program is free software. It may be redistributed and/or modified under
the terms of the GPL version 2 (or later), the Perl Artistic licence, or the
MIT licence.
COPYRIGHT

Class Attribute Summary collapse

Class Method Summary collapse

Class Attribute Details

.data_newObject (readonly)

:nodoc:



26
27
28
# File 'lib/diff/lcs/ldiff.rb', line 26

def data_new
  @data_new
end

.data_oldObject (readonly)

:nodoc:



26
27
28
# File 'lib/diff/lcs/ldiff.rb', line 26

def data_old
  @data_old
end

.file_newObject (readonly)

:nodoc:



25
26
27
# File 'lib/diff/lcs/ldiff.rb', line 25

def file_new
  @file_new
end

.file_oldObject (readonly)

:nodoc:



25
26
27
# File 'lib/diff/lcs/ldiff.rb', line 25

def file_old
  @file_old
end

.formatObject (readonly)

:nodoc:



24
25
26
# File 'lib/diff/lcs/ldiff.rb', line 24

def format
  @format
end

.linesObject (readonly)

:nodoc:



24
25
26
# File 'lib/diff/lcs/ldiff.rb', line 24

def lines
  @lines
end

Class Method Details

.run(args, _input = $stdin, output = $stdout, error = $stderr) ⇒ Object

:nodoc:



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
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
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
131
132
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
159
160
161
162
163
164
165
166
167
168
169
170
171
172
# File 'lib/diff/lcs/ldiff.rb', line 28

def run(args, _input = $stdin, output = $stdout, error = $stderr) # :nodoc:
  @binary = nil

  args.options do |o|
    o.banner = "Usage: #{File.basename($0)} [options] oldfile newfile"
    o.separator ""
    o.on(
      "-c", "-C", "--context [LINES]", Integer,
      "Displays a context diff with LINES lines", "of context. Default 3 lines."
    ) do |ctx|
      @format = :context
      @lines = ctx || 3
    end
    o.on(
      "-u", "-U", "--unified [LINES]", Integer,
      "Displays a unified diff with LINES lines", "of context. Default 3 lines."
    ) do |ctx|
      @format = :unified
      @lines = ctx || 3
    end
    o.on("-e", "Creates an 'ed' script to change", "oldfile to newfile.") do |_ctx|
      @format = :ed
    end
    o.on("-f", "Creates an 'ed' script to change", "oldfile to newfile in reverse order.") do |_ctx|
      @format = :reverse_ed
    end
    o.on(
      "-a", "--text",
      "Treat the files as text and compare them", "line-by-line, even if they do not seem", "to be text."
    ) do |_txt|
      @binary = false
    end
    o.on("--binary", "Treats the files as binary.") do |_bin|
      @binary = true
    end
    o.on("-q", "--brief", "Report only whether or not the files", "differ, not the details.") do |_ctx|
      @format = :report
    end
    o.on_tail("--help", "Shows this text.") do
      error << o
      return 0
    end
    o.on_tail("--version", "Shows the version of Diff::LCS.") do
      error << Diff::LCS::Ldiff::BANNER
      return 0
    end
    o.on_tail ""
    o.on_tail 'By default, runs produces an "old-style" diff, with output like UNIX diff.'
    o.parse!
  end

  unless args.size == 2
    error << args.options
    return 127
  end

  # Defaults are for old-style diff
  @format ||= :old
  @lines ||= 0

  file_old, file_new = *ARGV

  case @format
  when :context
    char_old = "*" * 3
    char_new = "-" * 3
  when :unified
    char_old = "-" * 3
    char_new = "+" * 3
  end

  # After we've read up to a certain point in each file, the number of
  # items we've read from each file will differ by FLD (could be 0).
  file_length_difference = 0

  data_old = IO.read(file_old)
  data_new = IO.read(file_new)

  # Test binary status
  if @binary.nil?
    old_txt = data_old[0, 4096].scan(/\0/).empty?
    new_txt = data_new[0, 4096].scan(/\0/).empty?
    @binary = !old_txt || !new_txt
  end

  unless @binary
    data_old = data_old.lines.to_a
    data_new = data_new.lines.to_a
  end

  # diff yields lots of pieces, each of which is basically a Block object
  if @binary
    diffs = (data_old == data_new)
  else
    diffs = Diff::LCS.diff(data_old, data_new)
    diffs = nil if diffs.empty?
  end

  return 0 unless diffs

  if @format == :report
    output << "Files #{file_old} and #{file_new} differ\n"
    return 1
  end

  if (@format == :unified) || (@format == :context)
    ft = File.stat(file_old).mtime.localtime.strftime("%Y-%m-%d %H:%M:%S.000000000 %z")
    output << "#{char_old} #{file_old}\t#{ft}\n"
    ft = File.stat(file_new).mtime.localtime.strftime("%Y-%m-%d %H:%M:%S.000000000 %z")
    output << "#{char_new} #{file_new}\t#{ft}\n"
  end

  # Loop over hunks. If a hunk overlaps with the last hunk, join them.
  # Otherwise, print out the old one.
  oldhunk = hunk = nil

  if @format == :ed
    real_output = output
    output = []
  end

  diffs.each do |piece|
    begin # rubocop:disable Style/RedundantBegin
      hunk = Diff::LCS::Hunk.new(data_old, data_new, piece, @lines, file_length_difference)
      file_length_difference = hunk.file_length_difference

      next unless oldhunk
      next if @lines.positive? && hunk.merge(oldhunk)

      output << oldhunk.diff(@format)
      output << "\n" if @format == :unified
    ensure
      oldhunk = hunk
    end
  end

  last = oldhunk.diff(@format, true)
  last << "\n" if last.respond_to?(:end_with?) && !last.end_with?("\n")

  output << last

  output.reverse_each { |e| real_output << e.diff(:ed_finish) } if @format == :ed

  1
end