源码高速定位工具-qwandry

https://github.com/adamsanderson/qwandry

qwandry 能高速定位到我们须要找到库文件，项目的工具。

Ruby中实现高速定位的方法有好多种。我知道的有三个:

使用bundle
命令是
```
cd `bundle show activerecord`
```
这种方法不方便的地方是仅仅能在支持bundle的环境下执行，并且仅仅能打开指定的gem文件夹
通过tag方法(tag 定位更精确，能够定位到方法级别)

局限: 仅仅能在相应的编辑器里执行
或者通过 qwandry

安装

gem install qwandry

使用

qw matrix        # opens ruby's matrix class in your editor
qw rails         # will ask you which version of rails you want to open
qw activerec 3.1 # will find the gem activerecord 3.1 and open it
You can also use Qwandry with other common languages:
qw -r python numpy # opens python's numpy library
qw -r perl URI     # open perl's URI library
qw -r node express # open express if it is installed for node

指定编辑器打开

EDITOR=subl qw activerecord 3.2.14

怎样自己定义?

touch ~/.qwandry/init.rb

然后copy例如以下内容到文件里

register 'projects' do
  add 'your project path'
end

default :ruby, :gem, :projects

解释

register 方法是将指定的文件夹打包
add 将文件夹增加到搜索中

default 是设置默认的搜索范围

实现的基本原理

通过配置 config 将非常多文件夹打包成 Package, 然后将 Package 打包成 Repository(仓库)
初始化一个Launcher(有Editor等)
依据输入的名称找到相应的Repository中的package(实际上是一个文件夹地址)
运行系统命令: editor(vim) path

源码分析

qwandry中比較重要的几个类

Repository

是一个基类，职责是存储全部的能够搜索的库文件夹和名称. 继承与它的子类必须实现 scan 方法。

它有两个子类: LibraryRepository 和 FlatRepository

Configuration

是一个用于配置搜索库的文件夹的类，能够动态的加入新的搜索路径。实现的方法比較track, 用的是万恶得 eval 方法。

Launcher

是用于打开指定文件夹的关键类。它有两个关键方法: find 和 launch

find方法的实现

    # Searches all of the loaded repositories for `name`
    def find(*pattern)
      # Create a glob pattern from the user's input, for instance
      # ["rails","2.3"] => "rails*2.3*"
      pattern = pattern.join('*')
      pattern << '*' unless pattern =~ /*$/
      
      packages = []
      repositories = Qwandry::Configuration.repositories
      repositories.each do |repo|
        packages.concat(repo.scan(pattern))
      end
      
      differentiate packages
      packages
    end

就是从仓库中找到合适得 Package

launch 方法的实现

    # Launches a Package or path represented by a String. Unless `editor` will
    # check against the environment by default.
    def launch(package, editor=nil)
      editor ||= @editor || ENV['QWANDRY_EDITOR'] || ENV['VISUAL'] || ENV['EDITOR']
      
      if (!editor) || (editor =~ /^s*$/) # if the editor is not set, or is blank, exit with a message:
        puts "Please set QWANDRY_EDITOR, VISUAL or EDITOR, or pass in an editor to use"
        exit 1
      end
      
      paths = package.is_a?
(String) ? [package] : package.paths
      # Editors may have options, 'mate -w' for instance
      editor_and_options = editor.strip.split(/s+/)
      
      Dir.chdir(File.dirname paths.first) do
        # Launch the editor with its options and any paths that we have been passed
        system(*(editor_and_options + paths))
      end
    end

主要的思路就是找到相应的editor打开指定的文件夹，打开文件夹的方法非常easy

system(*(editor_and_options + paths))