Everyday Scripting with Ruby 读书笔记(4)

---
用类捆绑数据和方法
Classes Bundle Data and Methods
---

# churn-classes.Sub.mine.rb

class SubversionRepository

  def initialize(root)
    @root = root
  end

  # 格式化时间
  def date(a_time)
    a_time.strftime("%Y-%m-%d")
  end
  
  # 计算修改次数 
  def change_count_for(name, start_date)
    extract_change_count_from(log(name, date(start_date)))
  end
  
  # 根据文本信息(解析字符串) 
  def extract_change_count_from(log_text)
    lines = log_text.split("\n")
    dashed_lines = lines.find_all do | line |
      line.include?('--------') 
    end
    dashed_lines.length - 1     
  end

  # 使用外部程序获取文本信息 
  def log(subsystem, start_date)
    timespan = "--revision HEAD:{#{start_date}}"
    
    `svn log #{timespan} #{@root}/#{subsystem}`
  end
end

# churn-classes.For.mine.rb

class Formatter
  
  def initialize
    @lines = []
  end
  
  #def use_date(date_string)
  #  @date_string = date_string
  #end
  
  def report_range(from_date, to_date)
    @from_date = from_date  # 通过实例变量实现封装
    @to_date = to_date
  end
  
  # 格式化时间
  def date(a_time)
    a_time.strftime("%Y-%m-%d")
  end
  
  def use_subsystem_with_change_count(name, count)
    @lines.push(subsystem_line(name, count))
  end
  
  def output
    ordered_lines = order_by_descending_change_count(@lines)
    return ([header] + ordered_lines).join("\n")  # 组成字符串数组,并通过join转换成字符串
  end
  
  # 处理打印标题信息
  def header
    "Changes between #{date(@from_date)} and #{date(@to_date)}:"
  end

  # 组成打印主体信息(参数:子项目,修改次数)
  def subsystem_line(subsystem_name, change_count)
    asterisks = asterisks_for(change_count)
    "#{subsystem_name.rjust(14)} #{asterisks} (#{change_count})"
  end

  # 计算星号 
  def asterisks_for(an_integer)
    '*' * (an_integer / 5.0).round
  end

  # 排序
  def order_by_descending_change_count(lines)
    lines.sort do | first, second |
      first_count = churn_line_to_int(first)
      second_count = churn_line_to_int(second)
      - (first_count <=> second_count)
    end
  end

  def churn_line_to_int(line)
    /\((\d+)\)/.match(line)[1].to_i
  end
end

# Exercise
# churn-classes.Churn.mine.rb

require 'churn-classes.Sub.mine'
require 'churn-classes.For.mine'

# 处理时间(过去一个月)   
def month_before(a_time)
  a_time - 28 * 24 * 60 * 60
end


if $0 == __FILE__
  subsystem_names = ['audit', 'fulfillment', 'persistence',
                     'ui', 'util', 'inventory']
  root="svn://rubyforge.org//var/svn/churn-demo"
  repository = SubversionRepository.new(root)
  
  #start_date = repository.date(month_before(Time.mktime(2005,9,2,0,0,0,0)))
  last_month = month_before(Time.mktime(2005,9,2,0,0,0,0))
  
  formatter = Formatter.new
  #formatter.use_date(start_date)
  formatter.report_range(last_month, Time.mktime(2005,9,2,0,0,0,0))

  subsystem_names.each do | name |
    formatter.use_subsystem_with_change_count(name,
                   repository.change_count_for(name, last_month))
  end
  puts formatter.output
end

** 运行结果 **
>ruby churn-classes.Churn.mine.rb
Changes between 2005-08-05 and 2005-09-02:
            ui ** (8)
         audit * (5)
          util * (4)
   persistence * (3)
   fulfillment  (2)
     inventory  (2)
>Exit code: 0
** **