def Init(self):
"""Initializes the payload object.
This is a prerequisite for any other public API call.
Raises:
PayloadError if object already initialized or fails to initialize
correctly.
"""
if self.is_init:
raise PayloadError('payload object already initialized')
self.manifest_hasher = hashlib.sha256()
# Read the file header.
self.payload_file.seek(self.payload_file_offset)
self.header = self._ReadHeader()
# Read the manifest.
manifest_raw = self._ReadManifest()
self.manifest = update_metadata_pb2.DeltaArchiveManifest()
self.manifest.ParseFromString(manifest_raw)
# Read the metadata signature (if any).
metadata_signature_raw = self._ReadMetadataSignature()
if metadata_signature_raw:
self.metadata_signature = update_metadata_pb2.Signatures()
self.metadata_signature.ParseFromString(metadata_signature_raw)
self.metadata_size = self.header.size + self.header.manifest_len
self.data_offset = self.metadata_size + self.header.metadata_signature_len
self.is_init = True
file_format_version = u64(args.payloadfile.read(8))
assert file_format_version == 2
manifest_size = u64(args.payloadfile.read(8))
metadata_signature_size = 0
if file_format_version > 1:
metadata_signature_size = u32(args.payloadfile.read(4))
manifest = args.payloadfile.read(manifest_size)
metadata_signature = args.payloadfile.read(metadata_signature_size)
data_offset = args.payloadfile.tell()
dam = um.DeltaArchiveManifest()
dam.ParseFromString(manifest)
block_size = dam.block_size
plobj = MyPayload(args.payloadfile, block_size, data_offset)
apobj = MyApplier(plobj)
for part in dam.partitions:
# for op in part.operations:
# assert op.type in (op.REPLACE, op.REPLACE_BZ, op.REPLACE_XZ), \
# 'unsupported op'
# extents = flatten([op.dst_extents for op in part.operations])
# assert verify_contiguous(extents), 'operations do not span full image'
dump_part(apobj, part)
def __init__(self, version=1): self.manifest = update_metadata_pb2.DeltaArchiveManifest() self.version = version self.block_size = 0