extract files from CAR file.
if the parent path is none, will use current path as root path.
cid is the root cid
extract files to current path from CAR file.
cid is the root cid
write ipld to output
file_cid is the file cid to write
output is the out the file write to.
the list file_name from car file by reader.
the list car file by reader.
reader is the CarReader
list_f is the list call function, first parameter is cid, the second is cid path.
the list_cid file_name from car file by reader.
archive the directory to the target CAR format file
path is the directory archived in to the CAR file.
to_carfile is the target file.
walk all directory, and record the directory informations.
WalkPath contain the index in children.