python验证文件是否可读可写

# Import python libs
import os

def is_writeable(path,check_parent=False):
    '''
    Check if a given path is writeable by the current user.

    :param path: The path to check
    :param check_parent: If the path to check does not exist,check for the
           ability to write to the parent directory instead
    :returns: True or False
    '''

    if os.access(path,os.F_OK) and os.access(path,os.W_OK):
        # The path exists and is writeable
        return True

    if os.access(path,os.F_OK) and not os.access(path,os.W_OK):
        # The path exists and is not writeable
        return False

    # The path does not exists or is not writeable

    if check_parent is False:
        # We're not allowed to check the parent directory of the provided path
        return False

    # Lets get the parent directory of the provided path
    parent_dir = os.path.dirname(path)

    if not os.access(parent_dir,os.F_OK):
        # Parent directory does not exit
        return False

    # Finally,return if we're allowed to write in the parent directory of the
    # provided path
    return os.access(parent_dir,os.W_OK)

def is_readable(path):
    '''
    Check if a given path is readable by the current user.

    :param path: The path to check
    :returns: True or False
    '''

    if os.access(path,os.R_OK):
        # The path exists and is readable
        return True

    # The path does not exist
    return False