Everyday Scripting with Ruby 读书笔记(2)

---
Churn项目：轻松编写脚本
The Churn Project: Writing Scripts without Fuss
---

subversion安装包下载： svn-1.4.5-setup.rar

#---
# Excerpted from "Everyday Scripting in Ruby"
# We make no guarantees that this code is fit for any purpose. 
# Visit http://www.pragmaticprogrammer.com/titles/bmsft for more book information.
#---

# This is the same as churn.v7.rb. It's a different file because
# of the mechanics of book production. 

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

# 处理打印标题信息
def header(an_svn_date)
  "Changes since #{an_svn_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)
  # 注释②
  "#{subsystem_name.rjust(14)} #{asterisks} (#{change_count})"
end

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

# 计算修改次数
def change_count_for(name, start_date)
  extract_change_count_from(svn_log(name, 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 |  # 注释③   
    line.include?('--------')     
  end
  dashed_lines.length - 1         
end

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

# 格式化时间
def svn_date(a_time)
  a_time.strftime("%Y-%m-%d")  # 注释①
end

if $0 == __FILE__
  subsystem_names = ['audit', 'fulfillment', 'persistence',
                     'ui', 'util', 'inventory']
  start_date = svn_date(month_before(Time.mktime(2005,9,2,0,0,0,0)))

  puts header(start_date)
  subsystem_names.each do | name |          
    puts subsystem_line(name, change_count_for(name, start_date))
  end
end

** 运行结果 **
>ruby churn.v7copy.rb
Changes since 2005-08-05:
         audit * (5)
   fulfillment  (2)
   persistence * (3)
            ui ** (8)
          util * (4)
     inventory  (2)
>Exit code: 0
** **


① Time对象的strftime用于格式化时间..
irb(main):005:0> Time.now.strftime('%m-%d %Y')
=> "10-28 2008"

② rjust用于实现右对齐..
irb(main):007:0> 'right'.rjust(2)
=> "right"
irb(main):008:0> 'right'.rjust(8)
=> "   right"

③ find_all: 获取代码块返回为真的所有元素, 然后放入一个新的数组作为返回值..
irb(main):009:0> ['abxc', 'xx', 'b', 'ycx'].find_all do | ele |
irb(main):010:1*   ele.include?('x')
irb(main):011:1>   end
=> ["abxc", "xx", "ycx"]

require 'test/unit'
require 'churn.v7copy'

class ChurnMyTests < Test::Unit::TestCase
  
  def test_month_before
    assert_equal(Time.local(2008,9,30), month_before(Time.local(2008,10,28)))
  end
  
  def test_svn_date
    assert_equal("2008-10-28",svn_date(Time.now))
  end
  
  def test_header
    assert_equal("Changes since 2008-10-28:", header(svn_date(Time.mktime(2008,10,28,0,0,0,0))))
  end
  
  def test_extract_change_count_from
    assert_equal(2,extract_change_count_from("------------------------------------------------------------------------
r2 | marick | 2005-08-07 14:26:21 -0500 (Mon, 07 Aug 2005) | 1 line

added code to handle merger
------------------------------------------------------------------------
r1 | marick | 2005-08-07 14:21:47 -0500 (Mon, 07 Aug 2005) | 1 line

first touches
No commit for revision 0.
------------------------------------------------------------------------"))
  end
  
  def test_asterisks_for
    assert_equal("*********", asterisks_for(46))
  end
  
end

** 运行结果 **
>ruby churn-mytest-v7copy.rb
Loaded suite churn-mytest-v7copy
Started
.....
Finished in 0.0 seconds.

5 tests, 5 assertions, 0 failures, 0 errors
>Exit code: 0
** **

# Exercises

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

# 处理打印标题信息
def header(an_svn_start_date, an_svn_today_date)
  "Changes between #{an_svn_start_date} and #{an_svn_today_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)
  change_text = change_text_from(change_count)
  unless change_count == 0
    return "#{subsystem_name.ljust(14)} #{change_text.ljust(14)} #{asterisks}"
  end
  return "#{subsystem_name.ljust(14)} #{'-'.ljust(14)} -"
end

# 计算星号
def asterisks_for(an_integer)
  if(an_integer < 3)
    '*'
  else
    '*' * (an_integer / 5.0).round
  end
end

# 处理修改次数信息
def change_text_from(an_integer)
  return "(#{an_integer} changes)"
end

# 计算修改次数
def change_count_for(name, start_date)
  extract_change_count_from(svn_log(name, 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 svn_log(subsystem, start_date)
  timespan = "--revision HEAD:{#{start_date}}"
  root = "svn://rubyforge.org//var/svn/churn-demo"
  
  `svn log #{timespan} #{root}/#{subsystem}`
end

# 格式化时间
def svn_date(a_time)
  a_time.strftime("%Y-%m-%d")
end

if $0 == __FILE__
  subsystem_names = ['audit', 'fulfillment', 'persistence',
                     'ui', 'util', 'inventory']
  start_date = svn_date(month_before(Time.mktime(2005,9,2,0,0,0,0)))
  today_date = svn_date(Time.now)

  puts header(start_date, today_date)
  subsystem_names.each do | name |          
    puts subsystem_line(name, change_count_for(name, start_date))
  end
end

** 运行结果 **
>ruby churn.v7copy.rb
Changes between 2005-08-05 and 2008-10-28:
audit          (5 changes)    *
fulfillment    (2 changes)    *
persistence    (3 changes)    *
ui             (8 changes)    **
util           (4 changes)    *
inventory      (2 changes)    *
>Exit code: 0
** **