1、cocoapods/lib/cocoapods/command/setup.rb

require 'fileutils' # ruby系统库

module Pod
  class Command
    class Setup < Command
      # 1、基本描述
      self.summary = 'Setup the CocoaPods environment'
      self.description = <<-DESC
        Creates a directory at `~/.cocoapods/repos` which will hold your spec-repos.
        This is where it will create a clone of the public `master` spec-repo from:

            https://github.com/CocoaPods/Specs

        If the clone already exists, it will ensure that it is up-to-date.
      DESC

      # 2、拷贝调用外部git可执行程序的代码
      # 已经在 cocoapods/lib/cocoapods/command.rb 文件中，
      # 执行 require 'cocoapods/command/setup' 符号导入，
      # 所以再次扩展打开 class Command 时，可以直接使用 cocoapods/command/setup.rb
      extend Executable # cocoapods/lib/cocoapods/executable.rb
      executable :git   # executable(:git) 生成调用git可执行程序的操作

      # 3、claide解析完命令行参数的回调处理
      def run
        # 3.1、提示：Setting up CocoaPods master repo...
        UI.section 'Setting up CocoaPods master repo' do
          if master_repo_dir.exist? # master repo dir 存在
            set_master_repo_url       # set_master_repo_url()
            set_master_repo_branch    # set_master_repo_branch()
            update_master_repo        # update_master_repo()
          else                      # master repo dir 不存在
            add_master_repo           # add_master_repo()
          end
        end

        # 3.2、提示：Setup completed
        UI.puts 'Setup completed'.green
      end

      #--------------------------------------#

      # @!group Setup steps

      # Sets the url of the master repo according to whether it is push.
      #
      # @return [void]
      #
      def set_master_repo_url
        Dir.chdir(master_repo_dir) do
          git('remote', 'set-url', 'origin', url)
          # git('remote', 'set-url', 'origin', url())
          # => git remote set-url origin 'https://github.com/CocoaPods/Specs.git'
        end
      end

      # Adds the master repo from the remote.
      #
      # @return [void]
      #
      def add_master_repo
        cmd = ['master', url, 'master', '--progress']
        # cmd = ['master', url(), 'master', '--progress']

        # cocoapods-1.5.3/lib/cocoapods/command/repo/add.rb
        # /Users/xiongzenghui/.rvm/rubies/ruby-2.3.0/lib/ruby/gems/2.3.0/gems/cocoapods-1.5.3/lib/cocoapods/command/repo/add.rb
        # 同样已经在 cocoapods/lib/cocoapods/command.rb 文件中，
        # 执行 require 'cocoapods/command/setup' 导入，
        # 执行 require 'cocoapods/command/repo' 符号导入
        Repo::Add.parse(cmd).run 
      end

      # Updates the master repo against the remote.
      #
      # @return [void]
      #
      def update_master_repo
        show_output = !config.silent?
        config.sources_manager.update('master', show_output) # 更新 master pod repo
      end

      # Sets the repo to the master branch.
      #
      # @note   This is not needed anymore as it was used for CocoaPods 0.6
      #         release candidates.
      #
      # @return [void]
      #
      def set_master_repo_branch
        Dir.chdir(master_repo_dir) do
          git %w(checkout master) # git checkout master 
        end
      end

      #--------------------------------------#

      # @!group Private helpers

      # @return [String] the url to use according to whether push mode should
      #         be enabled.
      #
      def url
        self.class.read_only_url # return 'https://github.com/CocoaPods/Specs.git'
      end

      # @return [String] the read only url of the master repo.
      #
      def self.read_only_url
        'https://github.com/CocoaPods/Specs.git'
      end

      # @return [Pathname] the directory of the master repo.
      #
      def master_repo_dir
        config.sources_manager.master_repo_dir
      end
    end
  end
end

2、pod setup 干的事情

• 1、master pod repo 不存在

  • 1）add_master_repo()

• 2、master pod repo 存在

  • 1）set_master_repo_url()
  • 2）set_master_repo_branch()
  • 3）update_master_repo()