Function _windows_shell_split

awscli/botocore/compat.py:186–277

Splits up a windows command as the built-in command parser would. Windows has potentially bizarre rules depending on where you look. When spawning a process via the Windows C runtime (which is what python does when you call popen) the rules are as follows: https://docs.microsoft.co

(s)

def _windows_shell_split(s):
    """Splits up a windows command as the built-in command parser would.

    Windows has potentially bizarre rules depending on where you look. When
    spawning a process via the Windows C runtime (which is what python does
    when you call popen) the rules are as follows:

    https://docs.microsoft.com/en-us/cpp/cpp/parsing-cpp-command-line-arguments

    To summarize:

    * Only space and tab are valid delimiters
    * Double quotes are the only valid quotes
    * Backslash is interpreted literally unless it is part of a chain that
      leads up to a double quote. Then the backslashes escape the backslashes,
      and if there is an odd number the final backslash escapes the quote.

    :param s: The command string to split up into parts.
    :return: A list of command components.
    """
    if not s:
        return []

    components = []
    buff = []
    is_quoted = False
    num_backslashes = 0
    for character in s:
        if character == '\\':
            # We can't simply append backslashes because we don't know if
            # they are being used as escape characters or not. Instead we
            # keep track of how many we've encountered and handle them when
            # we encounter a different character.
            num_backslashes += 1
        elif character == '"':
            if num_backslashes > 0:
                # The backslashes are in a chain leading up to a double
                # quote, so they are escaping each other.
                buff.append('\\' * int(floor(num_backslashes / 2)))
                remainder = num_backslashes % 2
                num_backslashes = 0
                if remainder == 1:
                    # The number of backslashes is uneven, so they are also
                    # escaping the double quote, so it needs to be added to
                    # the current component buffer.
                    buff.append('"')
                    continue

            # We've encountered a double quote that is not escaped,
            # so we toggle is_quoted.
            is_quoted = not is_quoted

            # If there are quotes, then we may want an empty string. To be
            # safe, we add an empty string to the buffer so that we make
            # sure it sticks around if there's nothing else between quotes.
            # If there is other stuff between quotes, the empty string will
            # disappear during the joining process.
            buff.append('')