Qt tx dialog: allow setting custom locktime

closes #2405
closes #1685

electrum/bitcoin.py

@@ -44,6 +44,10 @@ COINBASE_MATURITY = 100
 COIN = 100000000
 TOTAL_COIN_SUPPLY_LIMIT_IN_BTC = 21000000
 
+NLOCKTIME_MIN = 0
+NLOCKTIME_BLOCKHEIGHT_MAX = 500_000_000 - 1
+NLOCKTIME_MAX = 2 ** 32 - 1
+
 # supported types of transaction outputs
 # TODO kill these with fire
 TYPE_ADDRESS = 0

electrum/gui/qt/locktimeedit.py

@@ -0,0 +1,173 @@
+# Copyright (C) 2020 The Electrum developers
+# Distributed under the MIT software license, see the accompanying
+# file LICENCE or http://www.opensource.org/licenses/mit-license.php
+
+import time
+from datetime import datetime
+from typing import Optional, Any
+
+from PyQt5.QtCore import Qt, QDateTime
+from PyQt5.QtGui import QPalette, QPainter
+from PyQt5.QtWidgets import (QWidget, QLineEdit, QStyle, QStyleOptionFrame, QComboBox,
+                             QHBoxLayout, QDateTimeEdit)
+
+from electrum.i18n import _
+from electrum.bitcoin import NLOCKTIME_MIN, NLOCKTIME_MAX, NLOCKTIME_BLOCKHEIGHT_MAX
+
+from .util import char_width_in_lineedit
+
+
+class LockTimeEdit(QWidget):
+
+    def __init__(self, parent=None):
+        QWidget.__init__(self, parent)
+
+        hbox = QHBoxLayout()
+        self.setLayout(hbox)
+        hbox.setContentsMargins(0, 0, 0, 0)
+        hbox.setSpacing(0)
+
+        self.locktime_raw_e = LockTimeRawEdit()
+        self.locktime_height_e = LockTimeHeightEdit()
+        self.locktime_date_e = LockTimeDateEdit()
+        self.editors = [self.locktime_raw_e, self.locktime_height_e, self.locktime_date_e]
+
+        self.combo = QComboBox()
+        options = [_("Raw"), _("Block height"), _("Date")]
+        option_index_to_editor_map = {
+            0: self.locktime_raw_e,
+            1: self.locktime_height_e,
+            2: self.locktime_date_e,
+        }
+        default_index = 1
+        self.combo.addItems(options)
+
+        def on_current_index_changed(i):
+            for w in self.editors:
+                w.setVisible(False)
+                w.setEnabled(False)
+            prev_locktime = self.editor.get_locktime()
+            self.editor = option_index_to_editor_map[i]
+            if self.editor.is_acceptable_locktime(prev_locktime):
+                self.editor.set_locktime(prev_locktime)
+            self.editor.setVisible(True)
+            self.editor.setEnabled(True)
+
+        self.editor = option_index_to_editor_map[default_index]
+        self.combo.currentIndexChanged.connect(on_current_index_changed)
+        self.combo.setCurrentIndex(default_index)
+        on_current_index_changed(default_index)
+
+        hbox.addWidget(self.combo)
+        for w in self.editors:
+            hbox.addWidget(w)
+        hbox.addStretch(1)
+
+    def get_locktime(self) -> Optional[int]:
+        return self.editor.get_locktime()
+
+    def set_locktime(self, x: Any) -> None:
+        self.editor.set_locktime(x)
+
+
+class _LockTimeEditor:
+    min_allowed_value = NLOCKTIME_MIN
+    max_allowed_value = NLOCKTIME_MAX
+
+    def get_locktime(self) -> Optional[int]:
+        raise NotImplementedError()
+
+    def set_locktime(self, x: Any) -> None:
+        raise NotImplementedError()
+
+    @classmethod
+    def is_acceptable_locktime(cls, x: Any) -> bool:
+        if not x:  # e.g. empty string
+            return True
+        try:
+            x = int(x)
+        except:
+            return False
+        return cls.min_allowed_value <= x <= cls.max_allowed_value
+
+
+class LockTimeRawEdit(QLineEdit, _LockTimeEditor):
+
+    def __init__(self, parent=None):
+        QLineEdit.__init__(self, parent)
+        self.setFixedWidth(14 * char_width_in_lineedit())
+        self.textChanged.connect(self.numbify)
+
+    def numbify(self):
+        text = self.text().strip()
+        chars = '0123456789'
+        pos = self.cursorPosition()
+        pos = len(''.join([i for i in text[:pos] if i in chars]))
+        s = ''.join([i for i in text if i in chars])
+        self.set_locktime(s)
+        # setText sets Modified to False.  Instead we want to remember
+        # if updates were because of user modification.
+        self.setModified(self.hasFocus())
+        self.setCursorPosition(pos)
+
+    def get_locktime(self) -> Optional[int]:
+        try:
+            return int(str(self.text()))
+        except:
+            return None
+
+    def set_locktime(self, x: Any) -> None:
+        try:
+            x = int(x)
+        except:
+            self.setText('')
+            return
+        x = max(x, self.min_allowed_value)
+        x = min(x, self.max_allowed_value)
+        self.setText(str(x))
+
+
+class LockTimeHeightEdit(LockTimeRawEdit):
+    max_allowed_value = NLOCKTIME_BLOCKHEIGHT_MAX
+
+    def __init__(self, parent=None):
+        LockTimeRawEdit.__init__(self, parent)
+        self.setFixedWidth(20 * char_width_in_lineedit())
+        self.help_palette = QPalette()
+
+    def paintEvent(self, event):
+        super().paintEvent(event)
+        panel = QStyleOptionFrame()
+        self.initStyleOption(panel)
+        textRect = self.style().subElementRect(QStyle.SE_LineEditContents, panel, self)
+        textRect.adjust(2, 0, -10, 0)
+        painter = QPainter(self)
+        painter.setPen(self.help_palette.brush(QPalette.Disabled, QPalette.Text).color())
+        painter.drawText(textRect, Qt.AlignRight | Qt.AlignVCenter, "height")
+
+
+class LockTimeDateEdit(QDateTimeEdit, _LockTimeEditor):
+    min_allowed_value = NLOCKTIME_BLOCKHEIGHT_MAX + 1
+
+    def __init__(self, parent=None):
+        QDateTimeEdit.__init__(self, parent)
+        self.setMinimumDateTime(datetime.fromtimestamp(self.min_allowed_value))
+        self.setMaximumDateTime(datetime.fromtimestamp(self.max_allowed_value))
+        self.setDateTime(QDateTime.currentDateTime())
+
+    def get_locktime(self) -> Optional[int]:
+        dt = self.dateTime().toPyDateTime()
+        locktime = int(time.mktime(dt.timetuple()))
+        return locktime
+
+    def set_locktime(self, x: Any) -> None:
+        if not self.is_acceptable_locktime(x):
+            self.setDateTime(QDateTime.currentDateTime())
+            return
+        try:
+            x = int(x)
+        except:
+            self.setDateTime(QDateTime.currentDateTime())
+            return
+        dt = datetime.fromtimestamp(x)
+        self.setDateTime(dt)

electrum/gui/qt/transaction_dialog.py

@@ -41,7 +41,7 @@ from qrcode import exceptions
 
 from electrum.simple_config import SimpleConfig
 from electrum.util import quantize_feerate
-from electrum.bitcoin import base_encode
+from electrum.bitcoin import base_encode, NLOCKTIME_BLOCKHEIGHT_MAX
 from electrum.i18n import _
 from electrum.plugin import run_hook
 from electrum import simple_config
@@ -58,6 +58,7 @@ from .util import (MessageBoxMixin, read_QIcon, Buttons, icon_path,
 from .fee_slider import FeeSlider
 from .confirm_tx_dialog import TxEditor
 from .amountedit import FeerateEdit, BTCAmountEdit
+from .locktimeedit import LockTimeEdit
 
 if TYPE_CHECKING:
     from .main_window import ElectrumWindow
@@ -434,7 +435,13 @@ class BaseTxDialog(QDialog, MessageBoxMixin):
             self.date_label.show()
         else:
             self.date_label.hide()
-        self.locktime_label.setText(f"LockTime: {self.tx.locktime}")
+        if self.tx.locktime <= NLOCKTIME_BLOCKHEIGHT_MAX:
+            locktime_final_str = f"LockTime: {self.tx.locktime} (height)"
+        else:
+            locktime_final_str = f"LockTime: {self.tx.locktime} ({datetime.datetime.fromtimestamp(self.tx.locktime)})"
+        self.locktime_final_label.setText(locktime_final_str)
+        if self.locktime_e.get_locktime() is None:
+            self.locktime_e.set_locktime(self.tx.locktime)
         self.rbf_label.setText(_('Replace by fee') + f": {not self.tx.is_final()}")
 
         if tx_mined_status.header_hash:
@@ -611,8 +618,22 @@ class BaseTxDialog(QDialog, MessageBoxMixin):
         self.rbf_cb.setChecked(bool(self.config.get('use_rbf', True)))
         vbox_right.addWidget(self.rbf_cb)
 
-        self.locktime_label = TxDetailLabel()
-        vbox_right.addWidget(self.locktime_label)
+        self.locktime_final_label = TxDetailLabel()
+        vbox_right.addWidget(self.locktime_final_label)
+
+        locktime_setter_hbox = QHBoxLayout()
+        locktime_setter_hbox.setContentsMargins(0, 0, 0, 0)
+        locktime_setter_hbox.setSpacing(0)
+        locktime_setter_label = TxDetailLabel()
+        locktime_setter_label.setText("LockTime: ")
+        self.locktime_e = LockTimeEdit()
+        locktime_setter_hbox.addWidget(locktime_setter_label)
+        locktime_setter_hbox.addWidget(self.locktime_e)
+        locktime_setter_hbox.addStretch(1)
+        self.locktime_setter_widget = QWidget()
+        self.locktime_setter_widget.setLayout(locktime_setter_hbox)
+        vbox_right.addWidget(self.locktime_setter_widget)
+
         self.block_height_label = TxDetailLabel()
         vbox_right.addWidget(self.block_height_label)
         vbox_right.addStretch(1)
@@ -620,12 +641,15 @@ class BaseTxDialog(QDialog, MessageBoxMixin):
 
         vbox.addLayout(hbox_stats)
 
+        # below columns
         self.block_hash_label = TxDetailLabel(word_wrap=True)
         vbox.addWidget(self.block_hash_label)
 
         # set visibility after parenting can be determined by Qt
         self.rbf_label.setVisible(self.finalized)
         self.rbf_cb.setVisible(not self.finalized)
+        self.locktime_final_label.setVisible(self.finalized)
+        self.locktime_setter_widget.setVisible(not self.finalized)
 
     def set_title(self):
         self.setWindowTitle(_("Create transaction") if not self.finalized else _("Transaction"))
@@ -838,10 +862,12 @@ class PreviewTxDialog(BaseTxDialog, TxEditor):
             return
         self.finalized = True
         self.tx.set_rbf(self.rbf_cb.isChecked())
-        for widget in [self.fee_slider, self.feecontrol_fields, self.rbf_cb]:
+        self.tx.locktime = self.locktime_e.get_locktime()
+        for widget in [self.fee_slider, self.feecontrol_fields, self.rbf_cb,
+                       self.locktime_setter_widget, self.locktime_e]:
             widget.setEnabled(False)
             widget.setVisible(False)
-        for widget in [self.rbf_label]:
+        for widget in [self.rbf_label, self.locktime_final_label]:
             widget.setVisible(True)
         self.set_title()
         self.set_buttons_visibility()

electrum/lnpeer.py

@@ -1135,9 +1135,9 @@ class Peer(Logger):
         processed_onion = process_onion_packet(onion_packet, associated_data=payment_hash, our_onion_private_key=self.privkey)
         if chan.get_state() != channel_states.OPEN:
             raise RemoteMisbehaving(f"received update_add_htlc while chan.get_state() != OPEN. state was {chan.get_state()}")
-        if cltv_expiry >= 500_000_000:
+        if cltv_expiry > bitcoin.NLOCKTIME_BLOCKHEIGHT_MAX:
             asyncio.ensure_future(self.lnworker.force_close_channel(channel_id))
-            raise RemoteMisbehaving(f"received update_add_htlc with cltv_expiry >= 500_000_000. value was {cltv_expiry}")
+            raise RemoteMisbehaving(f"received update_add_htlc with cltv_expiry > BLOCKHEIGHT_MAX. value was {cltv_expiry}")
         # add htlc
         htlc = UpdateAddHtlc(amount_msat=amount_msat_htlc,
                              payment_hash=payment_hash,