module RSpec::Core::Metadata::MetadataHash

def [](key)
  store_computed(key) unless has_key?(key)
  super
end

def build_description_from(*parts)
  parts.map {|p| p.to_s}.inject do |desc, p|
    p =~ /^(#|::|\.)/ ? "#{desc}#{p}" : "#{desc} #{p}"
  end || ""
end

def fetch(key, *args)
  store_computed(key) unless has_key?(key)
  super
end

def file_and_line_number
  first_caller_from_outside_rspec =~ /(.+?):(\d+)(|:\d+)/
  return [Metadata::relative_path($1), $2.to_i]
end

def first_caller_from_outside_rspec
  self[:caller].detect {|l| l !~ /\/lib\/rspec\/core/}
end

def location
  "#{self[:file_path]}:#{self[:line_number]}"
end

def store_computed(key)
  case key
  when :location
    store(:location, location)
  when :file_path, :line_number
    file_path, line_number = file_and_line_number
    store(:file_path, file_path)
    store(:line_number, line_number)
  when :execution_result
    store(:execution_result, {})
  when :describes, :described_class
    klass = described_class
    store(:described_class, klass)
    # TODO (2011-11-07 DC) deprecate :describes as a key
    store(:describes, klass)
  when :full_description
    store(:full_description, full_description)
  when :description
    store(:description, build_description_from(*self[:description_args]))
  end
end