def validate_transfer_inputs()

in resdb_driver/transaction.py [0:0]

• 51 lines of code
• 15 McCabe index (conditional complexity)

    def validate_transfer_inputs(self, resdb, current_transactions=[]):
        # store the inputs so that we can check if the asset ids match
        input_txs = []
        input_conditions = []
        for input_ in self.inputs:
            input_txid = input_.fulfills.txid

            input_tx = resdb.get_transaction(input_txid)

            if input_tx is None:
                for ctxn in current_transactions:
                    if ctxn.id == input_txid:
                        input_tx = ctxn

            if input_tx is None:
                raise InputDoesNotExist(
                    "input `{}` doesn't exist".format(input_txid))

            spent = resdb.get_spent(
                input_txid, input_.fulfills.output, current_transactions
            )
            if spent:
                raise DoubleSpend(
                    "input `{}` was already spent".format(input_txid))

            output = input_tx.outputs[input_.fulfills.output]
            input_conditions.append(output)
            input_txs.append(input_tx)

        # Validate that all inputs are distinct
        links = [i.fulfills.to_uri() for i in self.inputs]
        if len(links) != len(set(links)):
            raise DoubleSpend('tx "{}" spends inputs twice'.format(self.id))

        # validate asset id
        asset_id = self.get_asset_id(input_txs)
        if asset_id != self.asset["id"]:
            raise AssetIdMismatch(
                (
                    "The asset id of the input does not"
                    " match the asset id of the"
                    " transaction"
                )
            )

        input_amount = sum(
            [input_condition.amount for input_condition in input_conditions]
        )
        output_amount = sum(
            [output_condition.amount for output_condition in self.outputs]
        )

        if output_amount != input_amount:
            raise AmountError(
                (
                    "The amount used in the inputs `{}`"
                    " needs to be same as the amount used"
                    " in the outputs `{}`"
                ).format(input_amount, output_amount)
            )

        if not self.inputs_valid(input_conditions):
            raise InvalidSignature("Transaction signature is invalid.")

        return True