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python getopt详解及简单实例

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这篇文章主要介绍了 python getopt详解及简单实例的相关资料,需要的朋友可以参考下

 python getopt详解

函数原型:

getopt.getopt(args, shortopts, longopts=[])

参数解释:

返回值:

源码分析

在Android生成OTA的build系统中,common.py文件中的ParseOptions函数就是用来解析输入参数的,我们来通过该函数的实现来分析一下getopt的使用。

函数源码如下:

def ParseOptions(argv, docstring, extra_opts="", extra_long_opts=(), extra_option_handler=None):
  try:
    opts, args = getopt.getopt(
      argv, "hvp:s:x" + extra_opts,
      ["help", "verbose", "path=", "signapk_path=", "extra_signapk_args=", "java_path=", "public_key_suffix=", "private_key_suffix=", "device_specific=", "extra="] + list(extra_long_opts))
  except getopt.GetoptError, err:
    Usage(docstring)
    print "**", str(err), "**"
    sys.exit(2)

  path_specified = False

  for o, a in opts:
    if o in ("-h", "--help"):
      Usage(docstring)
      sys.exit()
    elif o in ("-v", "--verbose"):
      OPTIONS.verbose = True
    elif o in ("-p", "--path"):
      OPTIONS.search_path = a
    elif o in ("--signapk_path",):
      OPTIONS.signapk_path = a
    elif o in ("--extra_singapk_args",):
      OPTIONS.extra_signapk_args = shlex.split(a)
    elif o in ("--java_path",):
      OPTIONS.java_path = a
    else:
      if extra_option_handler is None or not extra_option_handler(o, a):
      assert False, "unknown option \"%s\"" % (o,)

  os.environ["PATH"] = (os.path.join(OPTIONS.search_path, "bin") + os.pathsep + os.environ["PATH"])

  return args

其中,extra_option_handler可以理解为函数指针,它的功能也是解析opts的键值对。

extra_option_handler源码如下:

 def option_handler(o, a):
  if o in ("-b", "--board_config"):
   pass  # deprecated
  elif o in ("-k", "--package_key"):
   OPTIONS.package_key = a
  elif o in ("-i", "--incremental_from"):
   OPTIONS.incremental_source = a
  elif o in ("-w", "--wipe_user_data"):
   OPTIONS.wipe_user_data = True
  elif o in ("-n", "--no_prereq"):
   OPTIONS.omit_prereq = True
  elif o in ("-e", "--extra_script"):
   OPTIONS.extra_script = a
  elif o in ("-a", "--aslr_mode"):
   if a in ("on", "On", "true", "True", "yes", "Yes"):
    OPTIONS.aslr_mode = True
   else:
    OPTIONS.aslr_mode = False
  elif o in ("--worker_threads"):
   OPTIONS.worker_threads = int(a)
  else:
   return False
  return True

一般生成OAT全量包的参数argv如下:

argv = ['-v', '-p', 'out/host/linux-xxx', '-k', 'build/target/product/security/testkey',
 'out/target/product/xxx/obj/PACKAGING/target_files_intermediates/xxx-target_files.zip', 
'out/target/product/xxx/xxx_20150723.1340-ota.zip']

首先,对参数进行分析,其中短参数包括:

-v,-p,-k,

经过解析后,生成的结果如下所示:

opts = [('-v', ''), ('-p', 'out/host/linux-x86'), 
('-k', 'build/target/product/security/testkey')]
args =['out/target/product/xxx/obj/PACKAGING/target_files_intermediates/xxx-target_files.zip',
 'out/target/product/xxx/xxx_20150723.1340-ota.zip']

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