def readheaders(self):
    """Read header lines.

    Read header lines up to the entirely blank line that terminates them.
    The (normally blank) line that ends the headers is skipped, but not
    included in the returned list.  If a non-header line ends the headers,
    (which is an error), an attempt is made to backspace over it; it is
    never included in the returned list.

    The variable self.status is set to the empty string if all went well,
    otherwise it is an error message.  The variable self.headers is a
    completely uninterpreted list of lines contained in the header (so
    printing them will reproduce the header exactly as it appears in the
    file).

    If multiple header fields with the same name occur, they are combined
    according to the rules in RFC 2616 sec 4.2:

    Appending each subsequent field-value to the first, each separated
    by a comma. The order in which header fields with the same field-name
    are received is significant to the interpretation of the combined
    field value.
    """
    # XXX The implementation overrides the readheaders() method of
    # rfc822.Message.  The base class design isn't amenable to
    # customized behavior here so the method here is a copy of the
    # base class code with a few small changes.

    self.dict = {}
    self.unixfrom = ''
    self.headers = hlist = []
    self.status = ''
    headerseen = ""
    firstline = 1
    startofline = unread = tell = None
    if hasattr(self.fp, 'unread'):
      unread = self.fp.unread
    elif self.seekable:
      tell = self.fp.tell
    while True:
      if tell:
        try:
          startofline = tell()
        except __HOLE__:
          startofline = tell = None
          self.seekable = 0
      line = self.fp.readline(_MAXLINE + 1)
      if len(line) > _MAXLINE:
        raise LineTooLong("header line")
      if not line:
        self.status = 'EOF in headers'
        break
      # Skip unix From name time lines
      if firstline and line.startswith('From '):
        self.unixfrom = self.unixfrom + line
        continue
      firstline = 0
      if headerseen and line[0] in ' \t':
        # XXX Not sure if continuation lines are handled properly
        # for http and/or for repeating headers
        # It's a continuation line.
        hlist.append(line)
        self.addcontinue(headerseen, line.strip())
        continue
      elif self.iscomment(line):
        # It's a comment.  Ignore it.
        continue
      elif self.islast(line):
        # Note! No pushback here!  The delimiter line gets eaten.
        break
      headerseen = self.isheader(line)
      if headerseen:
        # It's a legal header line, save it.
        hlist.append(line)
        self.addheader(headerseen, line[len(headerseen)+1:].strip())
        continue
      else:
        # It's not a header line; throw it back and stop here.
        if not self.dict:
          self.status = 'No headers'
        else:
          self.status = 'Non-header line where header expected'
        # Try to undo the read.
        if unread:
          unread(line)
        elif tell:
          self.fp.seek(startofline)
        else:
          self.status = self.status + '; bad seek'
        break
dataset/ETHPy150Open GoogleCloudPlatform/python-compat-runtime/appengine-compat/exported_appengine_sdk/google/appengine/dist27/gae_override/httplib.py/HTTPMessage.readheaders