lib/git_repository/cloning.rb

	cloning.rb revision e6c44954655c89ba1d2a653055377e63b7f5a98d
require 'subprocess'

module GitRepository::Cloning
  extend ActiveSupport::Concern

  # Struct for old and new OID
  Ref = Struct.new(:previous, :current)

  def clone(url)
    set_section %w(remote origin),
      url:    url,
      fetch:  '+refs/*:refs/*',
      mirror: 'true'

    result = pull
    set_group_permissions
    result
  end

  def clone_svn(url)
    options = {url: url}

    # Do we have a standard layout?
    if self.class.svn_ls(url).split("\n") == %w( branches/ tags/ trunk/ )
      options.merge! \
        fetch:    'trunk:refs/remotes/trunk',
        branches: 'branches/*:refs/remotes/*',
        tags:     'tags/*:refs/remotes/tags/*'
    else
      options.merge! \
        fetch:    ':refs/remotes/git-svn'
    end

    set_section %w(svn-remote svn), options
    result = pull_svn
    set_group_permissions
    result
  end

  def pull
    with_head_change head_oid do
      git_exec('remote', 'update')
    end
  end

  # Fetches the latest commits and resets the local master
  def pull_svn
    old_head_oid = head_oid
    git_exec('svn', 'fetch')

    if svn_has_trunk?
      reset_branch(old_head_oid, 'master', "remotes/trunk")
    else
      reset_branch(old_head_oid, 'master', "remotes/git-svn")
    end

  end

  def svn_has_trunk?
    get_config('svn-remote.svn.fetch').starts_with?('trunk:')
  end

  # Sets the reference of a local branch
  def reset_branch(old_head_oid, branch, ref)
    with_head_change(old_head_oid) do
      git_exec('branch', '-f', branch, ref)
    end
  end

  module ClassMethods
    def is_git_repository?(address)
      # GIT_ASKPASS is set to the 'true' executable. It simply returns
      # successfully. This way, no credentials are supplied.
      !! exec('git', 'ls-remote', '-h', address, 'GIT_ASKPASS' => 'true')
    rescue Subprocess::Error => e
      if e.status == 128
        false
      else
        raise e
      end
    end

    def svn_ls(address)
      exec('svn', 'ls', address)
    end

    def is_svn_repository?(address)
      svn_ls address
      true
    rescue Subprocess::Error
      false
    end

    def exec(*args)
      Subprocess.run *args
    end
  end

  protected

  # Executes a git command
  def git_exec(*args)
    args.unshift 'git'
    args.push \
      GIT_DIR: local_path.to_s,
      LANG:    'C'

    Subprocess.run *args
  end

  # Yields the given block and returns the head OID
  # before and after yielding the block.
  def with_head_change(old_head_oid, *args)
    yield
    Ref.new(old_head_oid, head_oid)
  end

  def local_path
    repo.path
  end
end