# -*- coding: utf-8 -*-
"""
Copyright (c) 2018 beyond-blockchain.org.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
"""
import sys
import os
import traceback
current_dir = os.path.abspath(os.path.dirname(__file__))
sys.path.append(os.path.join(current_dir, "../.."))
from bbclib import id_length_conf
import bbclib
from bbclib.libs import bbclib_utils
[docs]class BBcReference:
"""Reference part in a transaction"""
def __init__(self, asset_group_id, transaction, ref_transaction=None, event_index_in_ref=0, id_length=None):
if id_length is not None:
bbclib.configure_id_length_all(id_length)
if asset_group_id is not None:
self.asset_group_id = asset_group_id[:id_length_conf["asset_group_id"]]
else:
self.asset_group_id = None
self.transaction_id = None
self.transaction = transaction
self.ref_transaction = ref_transaction
self.event_index_in_ref = event_index_in_ref
self.sig_indices = []
self.mandatory_approvers = None
self.option_approvers = None
self.option_sig_ids = []
if ref_transaction is None:
return
self.prepare_reference(ref_transaction=ref_transaction)
def __str__(self):
ret = " asset_group_id: %s\n" % bbclib_utils.str_binary(self.asset_group_id)
ret += " transaction_id: %s\n" % bbclib_utils.str_binary(self.transaction_id)
ret += " event_index_in_ref: %d\n" % self.event_index_in_ref
ret += " sig_indices: %s\n" % self.sig_indices
return ret
[docs] def prepare_reference(self, ref_transaction):
"""Read the previous referencing transaction"""
self.ref_transaction = ref_transaction
try:
evt = ref_transaction.events[self.event_index_in_ref]
if len(self.sig_indices) == 0:
for user in evt.mandatory_approvers:
self.sig_indices.append(self.transaction.get_sig_index(user))
for i in range(evt.option_approver_num_numerator):
dummy_id = bbclib_utils.get_random_value(4)
self.option_sig_ids.append(dummy_id)
self.sig_indices.append(self.transaction.get_sig_index(dummy_id))
else:
i = 0
for user in evt.mandatory_approvers:
self.transaction.set_sig_index(user, self.sig_indices[i])
i += 1
for i in range(evt.option_approver_num_numerator):
dummy_id = bbclib_utils.get_random_value(4)
self.option_sig_ids.append(dummy_id)
self.transaction.set_sig_index(dummy_id, self.sig_indices[i])
i += 1
self.mandatory_approvers = evt.mandatory_approvers
self.option_approvers = evt.option_approvers
ref_transaction.digest()
self.transaction_id = ref_transaction.transaction_id
except Exception as e:
print(traceback.format_exc())
[docs] def add_signature(self, user_id=None, signature=None):
"""Add signature in the reserved space
Args:
user_id (bytes): user_id of the signature owner
signature (BBcSignature): signature
"""
if user_id in self.option_approvers:
if len(self.option_sig_ids) == 0:
return
user_id = self.option_sig_ids.pop(0)
elif user_id not in self.mandatory_approvers:
return
self.transaction.add_signature(user_id=user_id, signature=signature)
[docs] def get_destinations(self):
"""Return the list of approvers in the referred transaction"""
return self.mandatory_approvers+self.option_approvers
[docs] def pack(self):
"""Pack this object
Returns:
bytes: packed binary data
"""
dat = bytearray(bbclib_utils.to_bigint(self.asset_group_id, size=id_length_conf["asset_group_id"]))
dat.extend(bbclib_utils.to_bigint(self.transaction_id, size=id_length_conf["transaction_id"]))
dat.extend(bbclib_utils.to_2byte(self.event_index_in_ref))
dat.extend(bbclib_utils.to_2byte(len(self.sig_indices)))
for i in range(len(self.sig_indices)):
dat.extend(bbclib_utils.to_2byte(self.sig_indices[i]))
return bytes(dat)
[docs] def unpack(self, data):
"""unpack into this object
Args:
data (bytes): packed binary data
Returns:
bool: True if successful
"""
ptr = 0
data_size = len(data)
try:
ptr, self.asset_group_id = bbclib_utils.get_bigint(ptr, data)
ptr, self.transaction_id = bbclib_utils.get_bigint(ptr, data)
ptr, self.event_index_in_ref = bbclib_utils.get_n_byte_int(ptr, 2, data)
ptr, signum = bbclib_utils.get_n_byte_int(ptr, 2, data)
self.sig_indices = []
for i in range(signum):
ptr, idx = bbclib_utils.get_n_byte_int(ptr, 2, data)
self.sig_indices.append(idx)
if ptr > data_size:
return False
except:
return False
return True