Contents

module Ruco
  class History
    def initialize(options)
      @options = options
      @stack = [@options.delete(:state)]
      @position = 0
    end

    def state
      @stack[@position]
    end

    def add(state)
      return unless tracked_field_changes?(state)
      remove_undone_states
      @position += 1
      @stack << state
      limit_stack
    end

    def undo
      @position = [@position - 1, 0].max
    end

    def redo
      @position = [@position + 1, @stack.size - 1].min
    end

    private

    def remove_undone_states
      @stack.slice!(@position + 1, 9999999)
    end

    def tracked_field_changes?(data)
      @options[:track].any? do |field|
        state[field] != data[field]
      end
    end

    def limit_stack
      to_remove = @stack.size - @options[:entries]
      return if to_remove < 1
      @stack.slice!(0, to_remove)
      @position -= to_remove
    end
  end
end

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
ruco-0.0.34	lib/ruco/history.rb
ruco-0.0.33	lib/ruco/history.rb