#!/usr/bin/env python3 # Copyright (c) 2020 The Bitcoin Core developers # Distributed under the MIT software license, see the accompanying # file COPYING or http://www.opensource.org/licenses/mit-license.php. """A limited-functionality wallet, which may replace a real wallet in tests""" from decimal import Decimal from enum import Enum from typing import Optional from test_framework.address import ADDRESS_BCRT1_P2WSH_OP_TRUE from test_framework.key import ECKey from test_framework.messages import ( COIN, COutPoint, CTransaction, CTxIn, CTxInWitness, CTxOut, ) from test_framework.script import ( CScript, LegacySignatureHash, OP_CHECKSIG, OP_TRUE, OP_NOP, SIGHASH_ALL, ) from test_framework.util import ( assert_equal, hex_str_to_bytes, satoshi_round, ) class MiniWalletMode(Enum): """Determines the transaction type the MiniWallet is creating and spending. For most purposes, the default mode ADDRESS_OP_TRUE should be sufficient; it simply uses a fixed bech32 P2WSH address whose coins are spent with a witness stack of OP_TRUE, i.e. following an anyone-can-spend policy. However, if the transactions need to be modified by the user (e.g. prepending scriptSig for testing opcodes that are activated by a soft-fork), or the txs should contain an actual signature, the raw modes RAW_OP_TRUE and RAW_P2PK can be useful. Summary of modes: | output | | tx is | can modify | needs mode | description | address | standard | scriptSig | signing ----------------+-------------------+-----------+----------+------------+---------- ADDRESS_OP_TRUE | anyone-can-spend | bech32 | yes | no | no RAW_OP_TRUE | anyone-can-spend | - (raw) | no | yes | no RAW_P2PK | pay-to-public-key | - (raw) | yes | yes | yes """ ADDRESS_OP_TRUE = 1 RAW_OP_TRUE = 2 RAW_P2PK = 3 class MiniWallet: def __init__(self, test_node, *, mode=MiniWalletMode.ADDRESS_OP_TRUE): self._test_node = test_node self._utxos = [] self._priv_key = None self._address = None assert isinstance(mode, MiniWalletMode) if mode == MiniWalletMode.RAW_OP_TRUE: self._scriptPubKey = bytes(CScript([OP_TRUE])) elif mode == MiniWalletMode.RAW_P2PK: # use simple deterministic private key (k=1) self._priv_key = ECKey() self._priv_key.set((1).to_bytes(32, 'big'), True) pub_key = self._priv_key.get_pubkey() self._scriptPubKey = bytes(CScript([pub_key.get_bytes(), OP_CHECKSIG])) elif mode == MiniWalletMode.ADDRESS_OP_TRUE: self._address = ADDRESS_BCRT1_P2WSH_OP_TRUE self._scriptPubKey = hex_str_to_bytes(self._test_node.validateaddress(self._address)['scriptPubKey']) def scan_blocks(self, *, start=1, num): """Scan the blocks for self._address outputs and add them to self._utxos""" for i in range(start, start + num): block = self._test_node.getblock(blockhash=self._test_node.getblockhash(i), verbosity=2) for tx in block['tx']: self.scan_tx(tx) def scan_tx(self, tx): """Scan the tx for self._scriptPubKey outputs and add them to self._utxos""" for out in tx['vout']: if out['scriptPubKey']['hex'] == self._scriptPubKey.hex(): self._utxos.append({'txid': tx['txid'], 'vout': out['n'], 'value': out['value']}) def sign_tx(self, tx, fixed_length=True): """Sign tx that has been created by MiniWallet in P2PK mode""" assert self._priv_key is not None (sighash, err) = LegacySignatureHash(CScript(self._scriptPubKey), tx, 0, SIGHASH_ALL) assert err is None # for exact fee calculation, create only signatures with fixed size by default (>49.89% probability): # 65 bytes: high-R val (33 bytes) + low-S val (32 bytes) # with the DER header/skeleton data of 6 bytes added, this leads to a target size of 71 bytes der_sig = b'' while not len(der_sig) == 71: der_sig = self._priv_key.sign_ecdsa(sighash) if not fixed_length: break tx.vin[0].scriptSig = CScript([der_sig + bytes(bytearray([SIGHASH_ALL]))]) def generate(self, num_blocks): """Generate blocks with coinbase outputs to the internal address, and append the outputs to the internal list""" blocks = self._test_node.generatetodescriptor(num_blocks, f'raw({self._scriptPubKey.hex()})') for b in blocks: cb_tx = self._test_node.getblock(blockhash=b, verbosity=2)['tx'][0] self._utxos.append({'txid': cb_tx['txid'], 'vout': 0, 'value': cb_tx['vout'][0]['value']}) return blocks def get_address(self): return self._address def get_utxo(self, *, txid: Optional[str]='', mark_as_spent=True): """ Returns a utxo and marks it as spent (pops it from the internal list) Args: txid: get the first utxo we find from a specific transaction Note: Can be used to get the change output immediately after a send_self_transfer """ index = -1 # by default the last utxo if txid: utxo = next(filter(lambda utxo: txid == utxo['txid'], self._utxos)) index = self._utxos.index(utxo) if mark_as_spent: return self._utxos.pop(index) else: return self._utxos[index] def send_self_transfer(self, **kwargs): """Create and send a tx with the specified fee_rate. Fee may be exact or at most one satoshi higher than needed.""" tx = self.create_self_transfer(**kwargs) self.sendrawtransaction(from_node=kwargs['from_node'], tx_hex=tx['hex']) return tx def create_self_transfer(self, *, fee_rate=Decimal("0.003"), from_node, utxo_to_spend=None, mempool_valid=True, locktime=0, sequence=0): """Create and return a tx with the specified fee_rate. Fee may be exact or at most one satoshi higher than needed.""" self._utxos = sorted(self._utxos, key=lambda k: k['value']) utxo_to_spend = utxo_to_spend or self._utxos.pop() # Pick the largest utxo (if none provided) and hope it covers the fee if self._priv_key is None: vsize = Decimal(96) # anyone-can-spend else: vsize = Decimal(168) # P2PK (73 bytes scriptSig + 35 bytes scriptPubKey + 60 bytes other) send_value = satoshi_round(utxo_to_spend['value'] - fee_rate * (vsize / 1000)) fee = utxo_to_spend['value'] - send_value assert send_value > 0 tx = CTransaction() tx.vin = [CTxIn(COutPoint(int(utxo_to_spend['txid'], 16), utxo_to_spend['vout']), nSequence=sequence)] tx.vout = [CTxOut(int(send_value * COIN), self._scriptPubKey)] tx.nLockTime = locktime if not self._address: # raw script if self._priv_key is not None: # P2PK, need to sign self.sign_tx(tx) else: # anyone-can-spend tx.vin[0].scriptSig = CScript([OP_NOP] * 35) # pad to identical size else: tx.wit.vtxinwit = [CTxInWitness()] tx.wit.vtxinwit[0].scriptWitness.stack = [CScript([OP_TRUE])] tx_hex = tx.serialize().hex() tx_info = from_node.testmempoolaccept([tx_hex])[0] assert_equal(mempool_valid, tx_info['allowed']) if mempool_valid: assert_equal(tx_info['vsize'], vsize) assert_equal(tx_info['fees']['base'], fee) return {'txid': tx_info['txid'], 'wtxid': tx_info['wtxid'], 'hex': tx_hex, 'tx': tx} def sendrawtransaction(self, *, from_node, tx_hex): from_node.sendrawtransaction(tx_hex) self.scan_tx(from_node.decoderawtransaction(tx_hex))