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rails--rails/actionpack/lib/action_dispatch/journey/visitors.rb

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# encoding: utf-8
2013-08-07 14:13:11 -04:00
module ActionDispatch
module Journey # :nodoc:
class Format
ESCAPE_PATH = ->(value) { Router::Utils.escape_path(value) }
ESCAPE_SEGMENT = ->(value) { Router::Utils.escape_segment(value) }
class Parameter < Struct.new(:name, :escaper)
def escape(value); escaper.call value; end
end
def self.required_path(symbol)
Parameter.new symbol, ESCAPE_PATH
end
def self.required_segment(symbol)
Parameter.new symbol, ESCAPE_SEGMENT
end
def initialize(parts)
@parts = parts
@children = []
@parameters = []
parts.each_with_index do |object,i|
case object
when Journey::Format
@children << i
when Parameter
@parameters << i
end
end
end
def evaluate(hash)
parts = @parts.dup
@parameters.each do |index|
param = parts[index]
value = hash[param.name]
return ''.freeze unless value
parts[index] = param.escape value
end
@children.each { |index| parts[index] = parts[index].evaluate(hash) }
parts.join
end
end
module Visitors # :nodoc:
class Visitor # :nodoc:
DISPATCH_CACHE = {}
def accept(node)
visit(node)
end
private
def visit node
send(DISPATCH_CACHE[node.type], node)
end
def binary(node)
visit(node.left)
visit(node.right)
end
def visit_CAT(n); binary(n); end
def nary(node)
node.children.each { |c| visit(c) }
end
def visit_OR(n); nary(n); end
def unary(node)
visit(node.left)
end
def visit_GROUP(n); unary(n); end
def visit_STAR(n); unary(n); end
def terminal(node); end
def visit_LITERAL(n); terminal(n); end
def visit_SYMBOL(n); terminal(n); end
def visit_SLASH(n); terminal(n); end
def visit_DOT(n); terminal(n); end
private_instance_methods(false).each do |pim|
next unless pim =~ /^visit_(.*)$/
DISPATCH_CACHE[$1.to_sym] = pim
end
end
class FormatBuilder < Visitor # :nodoc:
def accept(node); Journey::Format.new(super); end
def terminal(node); [node.left]; end
def binary(node)
visit(node.left) + visit(node.right)
end
def visit_GROUP(n); [Journey::Format.new(unary(n))]; end
def visit_STAR(n)
[Journey::Format.required_path(n.left.to_sym)]
end
def visit_SYMBOL(n)
symbol = n.to_sym
if symbol == :controller
[Journey::Format.required_path(symbol)]
else
[Journey::Format.required_segment(symbol)]
end
end
end
# Loop through the requirements AST
class Each < Visitor # :nodoc:
attr_reader :block
def initialize(block)
@block = block
end
def visit(node)
block.call(node)
super
end
end
class String < Visitor # :nodoc:
private
def binary(node)
[visit(node.left), visit(node.right)].join
end
def nary(node)
node.children.map { |c| visit(c) }.join '|'
end
def terminal(node)
node.left
end
def visit_GROUP(node)
"(#{visit(node.left)})"
end
end
class Dot < Visitor # :nodoc:
def initialize
@nodes = []
@edges = []
end
def accept(node)
super
<<-eodot
digraph parse_tree {
size="8,5"
node [shape = none];
edge [dir = none];
#{@nodes.join "\n"}
#{@edges.join("\n")}
}
eodot
end
private
def binary(node)
node.children.each do |c|
@edges << "#{node.object_id} -> #{c.object_id};"
end
super
end
def nary(node)
node.children.each do |c|
@edges << "#{node.object_id} -> #{c.object_id};"
end
super
end
def unary(node)
@edges << "#{node.object_id} -> #{node.left.object_id};"
super
end
def visit_GROUP(node)
@nodes << "#{node.object_id} [label=\"()\"];"
super
end
def visit_CAT(node)
@nodes << "#{node.object_id} [label=\"\"];"
super
end
def visit_STAR(node)
@nodes << "#{node.object_id} [label=\"*\"];"
super
end
def visit_OR(node)
@nodes << "#{node.object_id} [label=\"|\"];"
super
end
def terminal(node)
value = node.left
@nodes << "#{node.object_id} [label=\"#{value}\"];"
end
end
end
end
end