# Copyright (C) 2001-2006 Python Software Foundation

# Author: Barry Warsaw

# Contact: email-sig@python.org

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"""Various types of useful iterators and generators."""

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__all__ = [

    'body_line_iterator',

    'typed_subpart_iterator',

    'walk',

    # Do not include _structure() since it's part of the debugging API.

    ]

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import sys

from io import StringIO

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# This function will become a method of the Message class

def walk(self):

    """Walk over the message tree, yielding each subpart.

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    The walk is performed in depth-first order.  This method is a

    generator.

    """

    yield self

    if self.is_multipart():

        for subpart in self.get_payload():

            yield from subpart.walk()

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# These two functions are imported into the Iterators.py interface module.

def body_line_iterator(msg, decode=False):

    """Iterate over the parts, returning string payloads line-by-line.

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    Optional decode (default False) is passed through to .get_payload().

    """

    for subpart in msg.walk():

        payload = subpart.get_payload(decode=decode)

        if isinstance(payload, str):

            yield from StringIO(payload)

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