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Contents
require 'tsort'
module Dynflow
class Middleware::Resolver
include TSort
include Algebrick::TypeCheck
def initialize(register)
@register = Type! register, Middleware::Register
end
def result
@result ||= begin
@deps = normalize_rules(@register.rules)
self.tsort
end
end
private
# Takes eliminate :replace and :before rules.
# Returns hash, that maps middleware classes to their dependencies
def normalize_rules(rules)
deps = Hash.new { |h, k| h[k] = [] }
substitutions = {}
# replace before with after on oposite direction and build the
# substitutions dictionary
rules.each do |middleware_class, middleware_rules|
deps[middleware_class].concat(middleware_rules[:after])
middleware_rules[:before].each do |dependent_class|
deps[dependent_class] << middleware_class
end
middleware_rules[:replace].each do |replaced|
substitutions[replaced] = middleware_class
end
end
# replace the middleware to be substituted
substitutions.each do |old, new|
deps[new].concat(deps[old])
deps.delete(old)
end
# ignore deps, that are not present in the stack
deps.each do |middleware_class, middleware_deps|
middleware_deps.reject! { |dep| !deps.has_key?(dep) }
end
return deps
end
def tsort_each_node(&block)
@deps.each_key(&block)
end
def tsort_each_child(node, &block)
@deps.fetch(node).each(&block)
end
end
end
Version data entries
26 entries across 26 versions & 1 rubygems