signtx: fixes, refactoring
This commit is contained in:
Jan Pochyla
parent
adc3dde19e
commit
44a3b7f9f1
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@ -1,6 +1,6 @@
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from trezor.crypto.hashlib import sha256, ripemd160
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from trezor.crypto.curve import secp256k1
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from trezor.crypto import HDNode, base58
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from trezor.crypto import base58
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from . import coins
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@ -14,19 +14,10 @@ from trezor.messages.RequestType import TXINPUT, TXOUTPUT, TXMETA, TXFINISHED
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from trezor.messages.TxRequestSerializedType import TxRequestSerializedType
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from trezor.messages import OutputScriptType, InputScriptType
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# pylint: disable=W0622
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# Machine instructions
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# ===
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# TODO: we might want to define these in terms of data instead
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# - like TxRequest, but also for deriving keys for example
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# - sign_tx would turn to more or less pure code
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# - PROBLEM: async defs in python cannot yield. we could ignore that,
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# or use wrappers anyway, or just make it an ordinary old-style coroutine
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# and use yield / yield from everywhere
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def request_tx_meta(prev_hash: bytes=None):
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ack = yield TxRequest(type=TXMETA, prev_hash=prev_hash)
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@ -40,10 +31,10 @@ def request_tx_input(index: int, prev_hash: bytes=None):
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def request_tx_output(index: int, prev_hash: bytes=None):
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ack = yield TxRequest(type=TXOUTPUT, prev_hash=prev_hash, index=index)
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if prev_hash is not None:
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return ack.bin_outputs[0]
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else:
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if prev_hash is None:
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return ack.outputs[0]
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else:
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return ack.bin_outputs[0]
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def request_tx_finish():
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@ -58,7 +49,7 @@ def send_serialized_tx(serialized: TxRequestSerializedType):
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# ===
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async def sign_tx(tx: SignTx, root: HDNode):
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async def sign_tx(tx: SignTx, root):
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coin = coins.by_name(tx.coin_name)
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# Phase 1
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@ -73,29 +64,31 @@ async def sign_tx(tx: SignTx, root: HDNode):
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# h_first is used to make sure the inputs and outputs streamed in Phase 1
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# are the same as in Phase 2. it is thus not required to fully hash the
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# tx, as the SignTx info is streamed only once
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h_first = tx_hash_init() # not a real tx hash
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h_first = HashWriter(sha256) # not a real tx hash
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# pre-allocate the serialization structure for outputs
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txo_bin = TxOutputBinType()
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for i in range(tx.inputs_count):
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# STAGE_REQUEST_1_INPUT
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input = await request_tx_input(i)
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tx_write_input(h_first, input)
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total_in += await get_prevtx_output_value(input.prev_hash, input.prev_index)
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txi = await request_tx_input(i)
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write_tx_input(h_first, txi)
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total_in += await get_prevtx_output_value(txi.prev_hash, txi.prev_index)
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for o in range(tx.outputs_count):
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# STAGE_REQUEST_3_OUTPUT
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output = await request_tx_output(o)
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if output_is_change(output):
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txo = await request_tx_output(o)
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if output_is_change(txo):
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if change_out != 0:
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raise ValueError('Only one change output allowed')
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change_out = output.amount
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outputbin = output_compile(output, coin, root)
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tx_write_output(h_first, outputbin)
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total_out += outputbin.amount
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raise ValueError('Only one change output is valid')
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change_out = txo.amount
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txo_bin.amount = txo.amount
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txo_bin.script_pubkey = output_derive_script(txo, coin, root)
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write_tx_output(h_first, txo_bin)
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total_out += txo_bin.amount
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# TODO: display output
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# TODO: confirm output
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h_first_dig = tx_hash_digest(h_first)
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# TODO: check funds and tx fee
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# TODO: ask for confirmation
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@ -103,148 +96,193 @@ async def sign_tx(tx: SignTx, root: HDNode):
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# - sign inputs
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# - check that nothing changed
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for i_sign in range(tx.inputs_count):
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h_sign = tx_hash_init() # hash of what we are signing with this input
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h_second = tx_hash_init() # should be the same as h_first
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# pre-allocated result structure for streaming out the signatures and
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# parts of the serialized tx
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tx_ser = TxRequestSerializedType()
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input_sign = None
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for i_sign in range(tx.inputs_count):
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# hash of what we are signing with this input
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h_sign = HashWriter(sha256)
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# same as h_first, checked at the end of this iteration
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h_second = HashWriter(sha256)
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txi_sign = None
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key_sign = None
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key_sign_pub = None
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for i in range(tx.inputs_count):
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# STAGE_REQUEST_4_INPUT
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input = await request_tx_input(i)
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tx_write_input(h_second, input)
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txi = await request_tx_input(i)
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write_tx_input(h_second, txi)
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if i == i_sign:
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key_sign = node_derive(root, input.address_n)
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txi_sign = txi
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key_sign = node_derive(root, txi.address_n)
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key_sign_pub = key_sign.public_key()
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script_sig = input_derive_script_pre_sign(input, key_sign_pub)
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input_sign = input
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txi.script_sig = input_derive_script_pre_sign(
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txi, key_sign_pub)
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else:
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script_sig = bytes()
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input.script_sig = script_sig
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tx_write_input(h_sign, input)
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txi.script_sig = bytes()
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write_tx_input(h_sign, txi)
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for o in range(tx.outputs_count):
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# STAGE_REQUEST_4_OUTPUT
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output = await request_tx_output(o)
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outputbin = output_compile(output, coin, root)
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tx_write_output(h_second, outputbin)
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tx_write_output(h_sign, outputbin)
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txo = await request_tx_output(o)
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txo_bin.amount = txo.amount
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txo_bin.script_pubkey = output_derive_script(txo, coin, root)
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write_tx_output(h_second, txo_bin)
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write_tx_output(h_sign, txo_bin)
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if h_first_dig != tx_hash_digest(h_second):
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h_first_dig = tx_hash_digest(h_first, False)
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h_second_dig = tx_hash_digest(h_second, False)
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if h_first_dig != h_second_dig:
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raise ValueError('Transaction has changed during signing')
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signature = ecdsa_sign(key_sign, tx_hash_digest(h_sign))
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script_sig = input_derive_script_post_sign(
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input, key_sign_pub, signature)
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input_sign.script_sig = script_sig
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h_sign_dig = tx_hash_digest(h_sign, True)
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signature = ecdsa_sign(key_sign, h_sign_dig)
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txi_sign.script_sig = input_derive_script_post_sign(
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txi_sign, key_sign_pub, signature)
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# TODO: serialize the whole input at once, including the script_sig
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input_sign_w = BufferWriter(bytearray(), 0)
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tx_write_input(input_sign_w, input_sign)
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input_sign_b = input_sign_w.getvalue()
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txi_sign_w = BufferWriter()
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write_tx_input(txi_sign_w, txi_sign)
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txi_sign_b = txi_sign_w.getvalue()
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serialized = TxRequestSerializedType(
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signature_index=i_sign, signature=signature, serialized_tx=input_sign_b)
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await send_serialized_tx(serialized)
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tx_ser.signature_index = i_sign
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tx_ser.signature = signature
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tx_ser.serialized_tx = txi_sign_b
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await send_serialized_tx(tx_ser)
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del tx_ser.signature_index
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del tx_ser.signature
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for o in range(tx.outputs_count):
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# STAGE_REQUEST_5_OUTPUT
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output = await request_tx_output(o)
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outputbin = output_compile(output, coin, root)
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txo = await request_tx_output(o)
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txo_bin.amount = txo.amount
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txo_bin.script_pubkey = output_derive_script(txo, coin, root)
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outputbin_w = BufferWriter(bytearray(), 0)
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tx_write_input(outputbin_w, outputbin)
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outputbin_b = outputbin_w.getvalue()
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w_txo_bin = BufferWriter()
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write_tx_output(w_txo_bin, txo_bin)
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serialized = TxRequestSerializedType(serialized_tx=outputbin_b)
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await send_serialized_tx(serialized)
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tx_ser.serialized_tx = w_txo_bin.getvalue()
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await send_serialized_tx(tx_ser)
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await request_tx_finish()
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async def get_prevtx_output_value(prev_hash: bytes, prev_index: int) -> int:
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total_in = 0
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total_out = 0 # sum of output amounts
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# STAGE_REQUEST_2_PREV_META
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tx = await request_tx_meta(prev_hash)
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txh = HashWriter(sha256)
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h = tx_hash_init()
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tx_write_header(h, tx.version, tx.inputs_count)
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write_tx_header(txh, tx.version, tx.inputs_count)
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for i in range(tx.inputs_count):
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# STAGE_REQUEST_2_PREV_INPUT
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input = await request_tx_input(i, prev_hash)
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tx_write_input(h, input)
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tx_write_middle(h, tx.outputs_count)
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txi = await request_tx_input(i, prev_hash)
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write_tx_input(txh, txi)
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write_tx_middle(txh, tx.outputs_count)
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for o in range(tx.outputs_count):
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# STAGE_REQUEST_2_PREV_OUTPUT
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outputbin = await request_tx_output(o, prev_hash)
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tx_write_output(h, outputbin)
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txo_bin = await request_tx_output(o, prev_hash)
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write_tx_output(txh, txo_bin)
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if o == prev_index:
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total_in += outputbin.value
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total_out += txo_bin.value
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tx_write_footer(h, tx.locktime, False)
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if tx_hash_digest(h) != prev_hash:
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raise ValueError('PrevTx mismatch')
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return total_in
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write_tx_footer(txh, tx.locktime, False)
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if tx_hash_digest(txh, True) != prev_hash:
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raise ValueError('Encountered invalid prev_hash')
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return total_out
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# TX Hashing
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# ===
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def tx_hash_init():
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return HashWriter(sha256)
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def tx_hash_digest(w):
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return sha256(w.getvalue()).digest()
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def tx_hash_digest(w, double: bool):
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d = w.getvalue()
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if double:
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d = sha256(d).digest()
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return d
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# TX Outputs
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# ===
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def output_compile(output: TxOutputType, coin: CoinType, root: HDNode) -> TxOutputBinType:
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bin = TxOutputBinType()
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bin.amount = output.amount
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bin.script_pubkey = output_derive_script(output, coin, root)
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return bin
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def output_derive_script(output: TxOutputType, coin: CoinType, root: HDNode) -> bytes:
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if output.script_type == OutputScriptType.PAYTOADDRESS:
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raw_address = output_paytoaddress_extract_raw_address(output, root)
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if raw_address[0] != coin.address_type: # TODO: do this properly
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raise ValueError('Invalid address type')
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return script_paytoaddress_new(raw_address)
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def output_derive_script(o: TxOutputType, coin: CoinType, root) -> bytes:
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if o.script_type == OutputScriptType.PAYTOADDRESS:
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return script_paytoaddress_new(
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output_paytoaddress_extract_raw_address(o, coin, root))
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else:
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# TODO: other output script types
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raise ValueError('Unknown output script type')
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raise ValueError('Invalid output script type')
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return
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def output_paytoaddress_extract_raw_address(o: TxOutputType, root: HDNode) -> bytes:
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def output_paytoaddress_extract_raw_address(o: TxOutputType, coin: CoinType, root) -> bytes:
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o_address_n = getattr(o, 'address_n', None)
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o_address = getattr(o, 'address', None)
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if o_address_n:
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node = node_derive(root, o_address_n)
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# TODO: dont encode and decode again
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raw_address = base58.decode_check(node.address())
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# TODO: dont encode/decode more then necessary
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# TODO: detect correct address type
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if o_address_n is not None:
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n = node_derive(root, o_address_n)
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raw_address = base58.decode_check(n.address())
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elif o_address:
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raw_address = base58.decode_check(o_address)
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else:
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raise ValueError('Missing address')
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if raw_address[0] != coin.address_type:
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raise ValueError('Invalid address type')
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return raw_address
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def output_is_change(output: TxOutputType):
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address_n = getattr(output, 'address_n', None)
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return bool(address_n)
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# Tx Inputs
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# ===
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def input_derive_script_pre_sign(i: TxInputType, pubkey: bytes) -> bytes:
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if i.script_type == InputScriptType.SPENDADDRESS:
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return script_paytoaddress_new(ecdsa_hash_pubkey(pubkey))
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else:
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raise ValueError('Unknown input script type')
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def input_derive_script_post_sign(i: TxInputType, pubkey: bytes, signature: bytes) -> bytes:
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if i.script_type == InputScriptType.SPENDADDRESS:
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return script_spendaddress_new(pubkey, signature)
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else:
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raise ValueError('Unknown input script type')
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def node_derive(root, address_n: list):
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node = root.clone()
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node.derive_path(address_n)
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return node
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def ecdsa_hash_pubkey(pubkey: bytes) -> bytes:
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if pubkey[0] == 0x04:
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assert len(pubkey) == 65 # uncompressed format
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elif pubkey[0] == 0x00:
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assert len(pubkey) == 1 # point at infinity
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else:
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assert len(pubkey) == 33 # compresssed format
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h = sha256(pubkey).digest()
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h = ripemd160(h).digest()
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return h
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def ecdsa_sign(privkey: bytes, digest: bytes) -> bytes:
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return secp256k1.sign(privkey, digest)
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# TX Scripts
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# ===
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def script_paytoaddress_new(raw_address: bytes) -> bytearray:
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s = bytearray(25)
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s[0] = 0x76 # OP_DUP
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@ -256,75 +294,26 @@ def script_paytoaddress_new(raw_address: bytes) -> bytearray:
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return s
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def output_is_change(output: TxOutputType):
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address_n = getattr(output, 'address_n', None)
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return bool(address_n)
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# Tx Inputs
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# ===
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def input_derive_script_pre_sign(input: TxInputType, pubkey: bytes) -> bytes:
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if input.script_type == InputScriptType.SPENDADDRESS:
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return script_paytoaddress_new(ecdsa_get_pubkeyhash(pubkey))
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else:
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# TODO: other input script types
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raise ValueError('Unknown input script type')
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def input_derive_script_post_sign(input: TxInputType, pubkey: bytes, signature: bytes) -> bytes:
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if input.script_type == InputScriptType.SPENDADDRESS:
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return script_spendaddress_new(pubkey, signature)
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else:
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# TODO: other input script types
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raise ValueError('Unknown input script type')
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def script_spendaddress_new(pubkey: bytes, signature: bytes) -> bytearray:
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s = bytearray(25)
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w = BufferWriter(s, 0)
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w = BufferWriter()
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write_op_push(w, len(signature) + 1)
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write_bytes(w, signature)
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w.writebyte(0x01)
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write_op_push(w, len(pubkey))
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write_bytes(w, pubkey)
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return
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def node_derive(root: HDNode, address_n: list) -> HDNode:
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# TODO: this will probably need to be a part of the machine instructions
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node = root.clone()
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node.derive_path(address_n)
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return node
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def ecdsa_get_pubkeyhash(pubkey: bytes) -> bytes:
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if pubkey[0] == 0x04:
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assert len(pubkey) == 65 # uncompressed format
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elif pubkey[0] == 0x00:
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assert len(pubkey) == 1 # point at infinity
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else:
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assert len(pubkey) == 33 # compresssed format
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h = sha256(pubkey).digest()
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h = ripemd160(h).digest()
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return h
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async def ecdsa_sign(privkey: bytes, digest: bytes) -> bytes:
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return secp256k1.sign(privkey, digest)
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return w.getvalue()
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# TX Serialization
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# ===
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def tx_write_header(w, version: int, inputs_count: int):
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def write_tx_header(w, version: int, inputs_count: int):
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write_uint32(w, version)
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write_varint(w, inputs_count)
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def tx_write_input(w, i: TxInputType):
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def write_tx_input(w, i: TxInputType):
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write_bytes_rev(w, i.prev_hash)
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write_uint32(w, i.prev_index)
|
||||
write_varint(w, len(i.script_sig))
|
||||
|
|
@ -332,17 +321,17 @@ def tx_write_input(w, i: TxInputType):
|
|||
write_uint32(w, i.sequence)
|
||||
|
||||
|
||||
def tx_write_middle(w, outputs_count: int):
|
||||
def write_tx_middle(w, outputs_count: int):
|
||||
write_varint(w, outputs_count)
|
||||
|
||||
|
||||
def tx_write_output(w, o: TxOutputBinType):
|
||||
def write_tx_output(w, o: TxOutputBinType):
|
||||
write_uint64(w, o.amount)
|
||||
write_varint(w, len(o.script_pubkey))
|
||||
write_bytes(w, o.script_pubkey)
|
||||
|
||||
|
||||
def tx_write_footer(w, locktime: int, add_hash_type: bool):
|
||||
def write_tx_footer(w, locktime: int, add_hash_type: bool):
|
||||
write_uint32(w, locktime)
|
||||
if add_hash_type:
|
||||
write_uint32(w, 1)
|
||||
|
|
@ -417,13 +406,15 @@ def write_bytes_rev(w, buf: bytearray):
|
|||
|
||||
class BufferWriter:
|
||||
|
||||
def __init__(self, buf: bytearray, ofs: int):
|
||||
def __init__(self, buf: bytearray=None, ofs: int=0):
|
||||
# TODO: re-think the use of bytearrays, buffers, and other byte IO
|
||||
# i think we should just pass a pre-allocation size here, allocate the
|
||||
# bytearray and then trim it to zero. in this case, write() would
|
||||
# correspond to extend(), and writebyte() to append(). of course, the
|
||||
# the use-case of non-destructively writing to existing bytearray still
|
||||
# exists.
|
||||
if buf is None:
|
||||
buf = bytearray()
|
||||
self.buf = buf
|
||||
self.ofs = ofs
|
||||
|
||||
Loading…
Reference in New Issue