aboutsummaryrefslogtreecommitdiffstats
path: root/actionpack/lib/action_dispatch/journey/gtg/transition_table.rb
blob: d7ce6042c2d6ee346cbf74d654835fc549b53c1b (plain) (blame)
1
2
3
4
5
6
7
8
9
10
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
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
require 'action_dispatch/journey/nfa/dot'

module ActionDispatch
  module Journey # :nodoc:
    module GTG # :nodoc:
      class TransitionTable # :nodoc:
        include Journey::NFA::Dot

        attr_reader :memos

        def initialize
          @regexp_states = {}
          @string_states = {}
          @accepting     = {}
          @memos         = Hash.new { |h,k| h[k] = [] }
        end

        def add_accepting(state)
          @accepting[state] = true
        end

        def accepting_states
          @accepting.keys
        end

        def accepting?(state)
          @accepting[state]
        end

        def add_memo(idx, memo)
          @memos[idx] << memo
        end

        def memo(idx)
          @memos[idx]
        end

        def eclosure(t)
          Array(t)
        end

        def move(t, a)
          return [] if t.empty?

          regexps = []

          t.map { |s|
            if states = @regexp_states[s]
              regexps.concat states.map { |re, v| re === a ? v : nil }
            end

            if states = @string_states[s]
              states[a]
            end
          }.compact.concat regexps
        end

        def as_json(options = nil)
          simple_regexp = Hash.new { |h,k| h[k] = {} }

          @regexp_states.each do |from, hash|
            hash.each do |re, to|
              simple_regexp[from][re.source] = to
            end
          end

          {
            regexp_states: simple_regexp,
            string_states: @string_states,
            accepting:     @accepting
          }
        end

        def to_svg
          svg = IO.popen('dot -Tsvg', 'w+') { |f|
            f.write(to_dot)
            f.close_write
            f.readlines
          }
          3.times { svg.shift }
          svg.join.sub(/width="[^"]*"/, '').sub(/height="[^"]*"/, '')
        end

        def visualizer(paths, title = 'FSM')
          viz_dir   = File.join File.dirname(__FILE__), '..', 'visualizer'
          fsm_js    = File.read File.join(viz_dir, 'fsm.js')
          fsm_css   = File.read File.join(viz_dir, 'fsm.css')
          erb       = File.read File.join(viz_dir, 'index.html.erb')
          states    = "function tt() { return #{to_json}; }"

          fun_routes = paths.sample(3).map do |ast|
            ast.map { |n|
              case n
              when Nodes::Symbol
                case n.left
                when ':id' then rand(100).to_s
                when ':format' then %w{ xml json }.sample
                else
                  'omg'
                end
              when Nodes::Terminal then n.symbol
              else
                nil
              end
            }.compact.join
          end

          stylesheets = [fsm_css]
          svg         = to_svg
          javascripts = [states, fsm_js]

          # Annoying hack warnings
          fun_routes  = fun_routes
          stylesheets = stylesheets
          svg         = svg
          javascripts = javascripts

          require 'erb'
          template = ERB.new erb
          template.result(binding)
        end

        def []=(from, to, sym)
          to_mappings = states_hash_for(sym)[from] ||= {}
          to_mappings[sym] = to
        end

        def states
          ss = @string_states.keys + @string_states.values.flat_map(&:values)
          rs = @regexp_states.keys + @regexp_states.values.flat_map(&:values)
          (ss + rs).uniq
        end

        def transitions
          @string_states.flat_map { |from, hash|
            hash.map { |s, to| [from, s, to] }
          } + @regexp_states.flat_map { |from, hash|
            hash.map { |s, to| [from, s, to] }
          }
        end

        private

          def states_hash_for(sym)
            case sym
            when String
              @string_states
            when Regexp
              @regexp_states
            else
              raise ArgumentError, 'unknown symbol: %s' % sym.class
            end
          end
      end
    end
  end
end