commit f816134a0623cf464282ae1053e58edf312aa7a7 Author: Damian Johnson atagar@torproject.org Date: Thu Nov 15 10:18:16 2018 -0800

Internal _content_range() helper

Our new digest type and encoding arguments make our _digest_for_content() helper a poor fit. The only useful thing this helper does is narrow our content to a specific range. As such adding a helper that does only that.

This doesn't yet change any of our _digest_for_content() callers. That's next. --- stem/descriptor/__init__.py | 39 +++++++++++++++++++++++++++++---------- 1 file changed, 29 insertions(+), 10 deletions(-)

diff --git a/stem/descriptor/__init__.py b/stem/descriptor/__init__.py index cf661c58..07ed5b1b 100644 --- a/stem/descriptor/__init__.py +++ b/stem/descriptor/__init__.py @@ -929,19 +929,38 @@ class Descriptor(object): :raises: ValueError if the digest canot be calculated """

- raw_descriptor = self.get_bytes() + digest_content = self._content_range(start, end) + digest_hash = hashlib.sha1(stem.util.str_tools._to_bytes(digest_content)) + return stem.util.str_tools._to_unicode(digest_hash.hexdigest().upper())

- start_index = raw_descriptor.find(start) - end_index = raw_descriptor.find(end, start_index) + def _content_range(self, start = None, end = None): + """ + Provides the descriptor content inclusively between two substrings.

- if start_index == -1: - raise ValueError("Digest is for the range starting with '%s' but that isn't in our descriptor" % start) - elif end_index == -1: - raise ValueError("Digest is for the range ending with '%s' but that isn't in our descriptor" % end) + :param bytes start: start of the content range to get + :param bytes end: end of the content range to get

- digest_content = raw_descriptor[start_index:end_index + len(end)] - digest_hash = hashlib.sha1(stem.util.str_tools._to_bytes(digest_content)) - return stem.util.str_tools._to_unicode(digest_hash.hexdigest().upper()) + :raises: ValueError if either the start or end substring are not within our content + """ + + content = self.get_bytes() + start_index, end_index = None, None + + if start is not None: + start_index = content.find(start) + + if start_index == -1: + raise ValueError("'%s' is not present within our descriptor content" % start) + + if end is not None: + end_index = content.find(end, start_index) + + if end_index == -1: + raise ValueError("'%s' is not present within our descriptor content" % end) + + end_index += len(end) # make the ending index inclusive + + return content[start_index:end_index]

def __getattr__(self, name): # We can't use standard hasattr() since it calls this function, recursing.