Class: ActionDispatch::Journey::GTG::TransitionTable

Inherits:
Object
  • Object
show all
Includes:
NFA::Dot
Defined in:
lib/action_dispatch/journey/gtg/transition_table.rb

Overview

:nodoc:

Constant Summary collapse

DEFAULT_EXP =
/[^.\/?]+/
DEFAULT_EXP_ANCHORED =
/\A#{DEFAULT_EXP}\Z/

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from NFA::Dot

#to_dot

Constructor Details

#initializeTransitionTable

Returns a new instance of TransitionTable.



16
17
18
19
20
21
22
# File 'lib/action_dispatch/journey/gtg/transition_table.rb', line 16

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

Instance Attribute Details

#memosObject (readonly)

Returns the value of attribute memos.



11
12
13
# File 'lib/action_dispatch/journey/gtg/transition_table.rb', line 11

def memos
  @memos
end

Instance Method Details

#[]=(from, to, sym) ⇒ Object



163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
# File 'lib/action_dispatch/journey/gtg/transition_table.rb', line 163

def []=(from, to, sym)
  to_mappings = states_hash_for(sym)[from] ||= {}
  case sym
  when Regexp
    # we must match the whole string to a token boundary
    if sym == DEFAULT_EXP
      sym = DEFAULT_EXP_ANCHORED
    else
      sym = /\A#{sym}\Z/
    end
  when Symbol
    # account for symbols in the constraints the same as strings
    sym = sym.to_s
  end
  to_mappings[sym] = to
end

#accepting?(state) ⇒ Boolean

Returns:

  • (Boolean)


32
33
34
# File 'lib/action_dispatch/journey/gtg/transition_table.rb', line 32

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

#accepting_statesObject



28
29
30
# File 'lib/action_dispatch/journey/gtg/transition_table.rb', line 28

def accepting_states
  @accepting.keys
end

#add_accepting(state) ⇒ Object



24
25
26
# File 'lib/action_dispatch/journey/gtg/transition_table.rb', line 24

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

#add_memo(idx, memo) ⇒ Object



36
37
38
# File 'lib/action_dispatch/journey/gtg/transition_table.rb', line 36

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

#as_json(options = nil) ⇒ Object



98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
# File 'lib/action_dispatch/journey/gtg/transition_table.rb', line 98

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,
    stdparam_states: @stdparam_states,
    accepting:       @accepting
  }
end

#eclosure(t) ⇒ Object



44
45
46
# File 'lib/action_dispatch/journey/gtg/transition_table.rb', line 44

def eclosure(t)
  Array(t)
end

#memo(idx) ⇒ Object



40
41
42
# File 'lib/action_dispatch/journey/gtg/transition_table.rb', line 40

def memo(idx)
  @memos[idx]
end

#move(t, full_string, start_index, end_index) ⇒ Object



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
# File 'lib/action_dispatch/journey/gtg/transition_table.rb', line 48

def move(t, full_string, start_index, end_index)
  return [] if t.empty?

  next_states = []

  tok = full_string.slice(start_index, end_index - start_index)
  token_matches_default_component = DEFAULT_EXP_ANCHORED.match?(tok)

  t.each { |s, previous_start|
    if previous_start.nil?
      # In the simple case of a "default" param regex do this fast-path
      # and add all next states.
      if token_matches_default_component && states = @stdparam_states[s]
        states.each { |re, v| next_states << [v, nil].freeze if !v.nil? }
      end

      # When we have a literal string, we can just pull the next state
      if states = @string_states[s]
        next_states << [states[tok], nil].freeze unless states[tok].nil?
      end
    end

    # For regexes that aren't the "default" style, they may potentially
    # not be terminated by the first "token" [./?], so we need to continue
    # to attempt to match this regexp as well as any successful paths that
    # continue out of it. both paths could be valid.
    if states = @regexp_states[s]
      slice_start = if previous_start.nil?
        start_index
      else
        previous_start
      end

      slice_length = end_index - slice_start
      curr_slice = full_string.slice(slice_start, slice_length)

      states.each { |re, v|
        # if we match, we can try moving past this
        next_states << [v, nil].freeze if !v.nil? && re.match?(curr_slice)
      }

      # and regardless, we must continue accepting tokens and retrying this regexp.
      # we need to remember where we started as well so we can take bigger slices.
      next_states << [s, slice_start].freeze
    end
  }

  next_states
end

#statesObject



180
181
182
183
184
185
# File 'lib/action_dispatch/journey/gtg/transition_table.rb', line 180

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

#to_svgObject



115
116
117
118
119
120
121
122
123
# File 'lib/action_dispatch/journey/gtg/transition_table.rb', line 115

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

#transitionsObject



187
188
189
190
191
192
193
194
195
# File 'lib/action_dispatch/journey/gtg/transition_table.rb', line 187

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

#visualizer(paths, title = "FSM") ⇒ Object



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
# File 'lib/action_dispatch/journey/gtg/transition_table.rb', line 125

def visualizer(paths, title = "FSM")
  viz_dir   = File.join __dir__, "..", "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.filter_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
    }.join
  end

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

  fun_routes  = fun_routes
  stylesheets = stylesheets
  svg         = svg
  javascripts = javascripts

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