filelog: extract metadata parsing and packing...
filelog: extract metadata parsing and packing
_parsemeta returns the dictionary and a list of keys in the order they appear
in metadata. This can be used to repack the dictionary in the same order.
_packmeta creates metadata from a dictionary and an optional key-order list.
In _parsemeta, we use slices and re.search indead of str.index so we can accept
both buffers and strings.