Python os 模块，exec() 实例源码

def test_exec(self):
        '''Test the `exec` example.'''
        filename = 'exec-{}.py'
        if six.PY2:
            filename = filename.format('py2')
            expect = {
                'SEVERITY': {'UNDEFINED': 0, 'LOW': 0, 'MEDIUM': 2, 'HIGH': 0},
                'CONFIDENCE': {'UNDEFINED': 0, 'LOW': 0, 'MEDIUM': 0,
                               'HIGH': 2}
            }
        else:
            filename = filename.format('py3')
            expect = {
                'SEVERITY': {'UNDEFINED': 0, 'LOW': 0, 'MEDIUM': 1, 'HIGH': 0},
                'CONFIDENCE': {'UNDEFINED': 0, 'LOW': 0, 'MEDIUM': 0,
                               'HIGH': 1}
            }
        self.check_example(filename, expect)

def test_exec_as_root(self):
        '''Test for the `run_as_root=True` keyword argument.'''
        expect = {
            'SEVERITY': {'UNDEFINED': 0, 'LOW': 5, 'MEDIUM': 0, 'HIGH': 0},
            'CONFIDENCE': {'UNDEFINED': 0, 'LOW': 0, 'MEDIUM': 5, 'HIGH': 0}
        }
        self.check_example('exec-as-root.py', expect)

def test_os_exec(self):
        '''Test for `os.exec*`.'''
        expect = {
            'SEVERITY': {'UNDEFINED': 0, 'LOW': 8, 'MEDIUM': 0, 'HIGH': 0},
            'CONFIDENCE': {'UNDEFINED': 0, 'LOW': 0, 'MEDIUM': 8, 'HIGH': 0}
        }
        self.check_example('os-exec.py', expect)

def encode_to_py3bytes_or_py2str(s):
    """ takes anything and attempts to return a py2 string or py3 bytes.  this
    is typically used when creating command + arguments to be executed via
    os.exec* """

    fallback_encoding = "utf8"

    if IS_PY3:
        # if we're already bytes, do nothing
        if isinstance(s, bytes):
            pass
        else:
            s = str(s)
            try:
                s = bytes(s, DEFAULT_ENCODING)
            except UnicodeEncodeError:
                s = bytes(s, fallback_encoding)
    else:
        # attempt to convert the thing to unicode from the system's encoding
        try:
            s = unicode(s, DEFAULT_ENCODING)
        # if the thing is already unicode, or it's a number, it can't be
        # coerced to unicode with an encoding argument, but if we leave out
        # the encoding argument, it will convert it to a string, then to unicode
        except TypeError:
            s = unicode(s)

        # now that we have guaranteed unicode, encode to our system encoding,
        # but attempt to fall back to something
        try:
            s = s.encode(DEFAULT_ENCODING)
        except:
            s = s.encode(fallback_encoding, "replace")
    return s

def compile_args(args, kwargs, sep, prefix):
    """ takes args and kwargs, as they were passed into the command instance
    being executed with __call__, and compose them into a flat list that
    will eventually be fed into exec.  example:

    with this call:

        sh.ls("-l", "/tmp", color="never")

    this function receives

        args = ['-l', '/tmp']
        kwargs = {'color': 'never'}

    and produces

        ['-l', '/tmp', '--color=never']

    """
    processed_args = []
    encode = encode_to_py3bytes_or_py2str

    # aggregate positional args
    for arg in args:
        if isinstance(arg, (list, tuple)):
            if isinstance(arg, GlobResults) and not arg:
                arg = [arg.path]

            for sub_arg in arg:
                processed_args.append(encode(sub_arg))
        elif isinstance(arg, dict):
            processed_args += aggregate_keywords(arg, sep, prefix, raw=True)
        else:
            processed_args.append(encode(arg))

    # aggregate the keyword arguments
    processed_args += aggregate_keywords(kwargs, sep, prefix)

    return processed_args

def run_repl(env): # pragma: no cover
    banner = "\n>> sh v{version}\n>> https://github.com/amoffat/sh\n"

    print(banner.format(version=__version__))
    while True:
        try:
            line = raw_input("sh> ")
        except (ValueError, EOFError):
            break

        try:
            exec(compile(line, "<dummy>", "single"), env, env)
        except SystemExit:
            break
        except:
            print(traceback.format_exc())

    # cleans up our last line
    print("")




# this is a thin wrapper around THIS module (we patch sys.modules[__name__]).
# this is in the case that the user does a "from sh import whatever"
# in other words, they only want to import certain programs, not the whole
# system PATH worth of commands.  in this case, we just proxy the
# import lookup to our Environment class