text: #!/usr/bin/env python
  # Copyright (c) 2009, Willow Garage, Inc.
  # All rights reserved.
  # 
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions are met:
  # 
  #     * Redistributions of source code must retain the above copyright
  #       notice, this list of conditions and the following disclaimer.
  #     * Redistributions in binary form must reproduce the above copyright
  #       notice, this list of conditions and the following disclaimer in the
  #       documentation and/or other materials provided with the distribution.
  #     * Neither the name of the Willow Garage, Inc. nor the names of its
  #       contributors may be used to endorse or promote products derived from
  #       this software without specific prior written permission.
  # 
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  # ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  # LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  # CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  # SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  # INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  # CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  # POSSIBILITY OF SUCH DAMAGE.
  
  # Author Tully Foote/tfoote@willowgarage.com
  
  import subprocess
  
  from ..installers import PackageManagerInstaller
  from .source import SOURCE_INSTALLER
  
  ARCH_OS_NAME = 'arch'
  PACMAN_INSTALLER = 'pacman'
  
  def register_installers(context):
      context.set_installer(PACMAN_INSTALLER, PacmanInstaller())
      
  def register_platforms(context):
      context.add_os_installer_key(ARCH_OS_NAME, SOURCE_INSTALLER)
      context.add_os_installer_key(ARCH_OS_NAME, PACMAN_INSTALLER)
      context.set_default_os_installer_key(ARCH_OS_NAME, PACMAN_INSTALLER)
  
  def pacman_detect_single(p):
      return not subprocess.call(['pacman', '-Q', p], stdout=subprocess.PIPE, stderr=subprocess.PIPE)    
  
  def pacman_detect(packages):
      return [p for p in packages if pacman_detect_single(p)]
  
  class PacmanInstaller(PackageManagerInstaller):
  
      def __init__(self):
          super(PacmanInstaller, self).__init__(pacman_detect)
  
      def get_install_command(self, resolved, interactive=True, reinstall=False):
          #TODO: interactive switch
          packages = self.get_packages_to_install(resolved, reinstall=reinstall)        
          if not packages:
              return []
          else:
              return [['sudo', 'pacman', '-Sy', '--needed', p] for p in packages]
  