def _fold(self, name, value, sanitize):
parts = []
parts.append("%s: " % name)
if isinstance(value, str):
if _has_surrogates(value):
if sanitize:
h = header.Header(
value, charset=_charset.UNKNOWN8BIT, header_name=name
)
else:
# If we have raw 8bit data in a byte string, we have no idea
# what the encoding is. There is no safe way to split this
# string. If it's ascii-subset, then we could do a normal
# ascii split, but if it's multibyte then we could break the
# string. There's no way to know so the least harm seems to
# be to not split the string and risk it being too long.
parts.append(value)
h = None
else:
h = header.Header(value, header_name=name)
else:
# Assume it is a Header-like object.
h = value
if h is not None:
parts.append(
h.encode(linesep=self.linesep, maxlinelen=self.max_line_length)
)
parts.append(self.linesep)
return "".join(parts)
def _sanitize_header(self, name, value):
# If the header value contains surrogates, return a Header using
# the unknown-8bit charset to encode the bytes as encoded words.
if not isinstance(value, str):
# Assume it is already a header object
return value
if _has_surrogates(value):
return header.Header(value, charset=_charset.UNKNOWN8BIT, header_name=name)
else:
return value