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from debian import deb822
from dedup.arreader import ArReader
from dedup.hashing import hash_file
def process_control(control_contents):
"""Parses the contents of a control file from a control.tar of a Debian
package and returns a dictionary containing the fields relevant to dedup.
@type control_contents: bytes
@rtype: {str: object}
"""
control = deb822.Packages(control_contents)
package = control["package"]
try:
source = control["source"].split()[0]
except KeyError:
source = package
version = control["version"]
architecture = control["architecture"]
# deb822 currently returns :any dependencies raw. see #670679
depends = set(dep[0]["name"].split(u':', 1)[0]
for dep in control.relations.get("depends", ())
if len(dep) == 1)
return dict(package=package, source=source, version=version,
architecture=architecture, depends=depends)
class MultiHash(object):
def __init__(self, *hashes):
self.hashes = hashes
def update(self, data):
for hasher in self.hashes:
hasher.update(data)
def get_tar_hashes(tar, hash_functions):
"""Given a TarFile read all regular files and compute all of the given hash
functions on each file.
@type tar: tarfile.TarFile
@param hash_functions: a sequence of parameter-less functions each creating a
new hashlib-like object
@rtype: gen((str, int, {str: str}}
@returns: an iterable of (filename, filesize, hashes) tuples where
hashes is a dict mapping hash function names to hash values
"""
for elem in tar:
if not elem.isreg(): # excludes hard links as well
continue
hasher = MultiHash(*[func() for func in hash_functions])
hasher = hash_file(hasher, tar.extractfile(elem))
hashes = {}
for hashobj in hasher.hashes:
hashvalue = hashobj.hexdigest()
if hashvalue:
hashes[hashobj.name] = hashvalue
yield (elem.name, elem.size, hashes)
class DebExtractor(object):
"Base class for extracting desired features from a Debian package."
def process(self, filelike):
"""Process a Debian package.
@param filelike: is a file-like object containing the contents of the
Debian packge and can be read once without seeks.
"""
af = ArReader(filelike)
af.read_magic()
while True:
try:
name = af.read_entry()
except EOFError:
break
else:
self.handle_ar_member(name, af)
self.handle_ar_end()
def handle_ar_member(self, name, filelike):
"""Handle an ar archive member of the Debian package.
@type name: bytes
@param name: is the name of the member
@param filelike: is a file-like object containing the contents of the
member and can be read once without seeks.
"""
def handle_ar_end(self):
"Handle the end of the ar archive of the Debian package."
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