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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