Added CPFP Feature for Kivy GUI (#7487)

implements https://github.com/spesmilo/electrum/issues/5507

electrum/gui/kivy/uix/dialogs/cpfp_dialog.py

@@ -0,0 +1,153 @@
+from typing import TYPE_CHECKING, Optional
+
+from kivy.app import App
+from kivy.factory import Factory
+from kivy.properties import ObjectProperty
+from kivy.lang import Builder
+
+from electrum.gui.kivy.i18n import _
+
+if TYPE_CHECKING:
+    from ...main_window import ElectrumWindow
+
+from .fee_dialog import FeeSliderDialog
+from electrum.gui.qt.amountedit import BTCAmountEdit
+from electrum.util import format_satoshis_plain
+
+Builder.load_string('''
+<CPFPDialog@Popup>
+    title: _('Child Pays for Parent')
+    size_hint: 0.8, 0.8
+    pos_hint: {'top':0.9}
+    method: 0
+    BoxLayout:
+        orientation: 'vertical'
+        padding: '10dp'
+        GridLayout:
+            height: self.minimum_height
+            size_hint_y: None
+            cols: 1
+            spacing: '10dp'
+            TopLabel:
+                text:
+                    _(\
+                    "A CPFP is a transaction that sends an unconfirmed output back to "\
+                    "yourself, with a high fee. The goal is to have miners confirm "\
+                    "the parent transaction in order to get the fee attached to the "\
+                    "child transaction.")
+            BoxLabel:
+                id: total_size
+                text: _('Total Size')
+                value: ''
+            BoxLabel:
+                id: input_amount
+                text: _('Input amount')
+                value: ''
+            BoxLabel:
+                id: output_amount
+                text: _('Output amount')
+                value: ''
+            BoxLabel:
+                id: fee_for_child
+                text: _('Fee for child')
+                value: ''
+        BoxLayout:
+            orientation: 'horizontal'
+            size_hint: 1, 0.5
+            Label:
+                text: _('Target') + ' (%s):' % (_('mempool') if root.method == 2 else _('ETA') if root.method == 1 else _('static'))
+            Button:
+                id: fee_target
+                text: ''
+                background_color: (0,0,0,0)
+                bold: True
+                on_release:
+                    root.method  = (root.method + 1) % 3
+                    root.update_slider()
+                    root.on_slider(root.slider.value)
+
+        Slider:
+            id: slider
+            range: 0, 4
+            step: 1
+            on_value: root.on_slider(self.value)
+        GridLayout:
+            height: self.minimum_height
+            size_hint_y: None
+            cols: 1
+            spacing: '10dp'
+            BoxLabel:
+                id: total_fee
+                text: _('Total fee')
+                value: ''
+            BoxLabel:
+                id: total_feerate
+                text: _('Total feerate')
+                value: ''
+        Widget:
+            size_hint: 1, 1
+        BoxLayout:
+            orientation: 'horizontal'
+            size_hint: 1, 0.5
+            Button:
+                text: 'Cancel'
+                size_hint: 0.5, None
+                height: '48dp'
+                on_release: root.dismiss()
+            Button:
+                text: 'OK'
+                size_hint: 0.5, None
+                height: '48dp'
+                on_release:
+                    root.dismiss()
+                    root.on_ok()
+''')
+
+class CPFPDialog(FeeSliderDialog, Factory.Popup):
+
+    def __init__(self, app: 'ElectrumWindow', parent_fee, total_size, new_tx, callback):
+        self.app = app
+        self.parent_fee = parent_fee
+        self.total_size = total_size
+        self.new_tx = new_tx
+        self.max_fee = self.new_tx.output_value()
+        Factory.Popup.__init__(self)
+        FeeSliderDialog.__init__(self, app.electrum_config, self.ids.slider)
+        self.callback = callback
+        self.config = app.electrum_config
+        self.ids.total_size.value = ('%d bytes'% self.total_size)
+        self.ids.input_amount.value = self.app.format_amount(self.max_fee) + ' ' + self.app._get_bu()
+        self.update_slider()
+        self.update_text()
+
+    def get_child_fee_from_total_feerate(self, fee_per_kb: Optional[int]) -> Optional[int]:
+        if fee_per_kb is None:
+            return None
+        fee = fee_per_kb * self.total_size / 1000 - self.parent_fee
+        fee = round(fee)
+        fee = min(self.max_fee, fee)
+        fee = max(self.total_size, fee)  # pay at least 1 sat/byte for combined size
+        return fee
+
+    def update_text(self):
+        target, tooltip, dyn = self.config.get_fee_target()
+        self.ids.fee_target.text = target
+        fee_per_kb = self.config.fee_per_kb()
+        self.fee = self.get_child_fee_from_total_feerate(fee_per_kb)
+        if self.fee is None:
+            self.ids.fee_for_child.value = "unknown"
+        else:
+            comb_fee = self.fee + self.parent_fee
+            comb_feerate = 1000 * comb_fee / self.total_size
+            self.ids.fee_for_child.value = self.app.format_amount_and_units(self.fee)
+            self.ids.output_amount.value = self.app.format_amount_and_units(self.max_fee-self.fee) if self.max_fee > self.fee else ''
+            self.ids.total_fee.value = self.app.format_amount_and_units(self.fee+self.parent_fee)
+            self.ids.total_feerate.value = self.app.format_fee_rate(comb_feerate)
+
+    def on_ok(self):
+        fee = self.fee
+        self.callback(fee, self.max_fee)
+
+    def on_slider(self, value):
+        self.save_config()
+        self.update_text()

electrum/gui/kivy/uix/dialogs/tx_dialog.py

@@ -14,7 +14,7 @@ from kivy.uix.button import Button
 
 from electrum.util import InvalidPassword
 from electrum.address_synchronizer import TX_HEIGHT_LOCAL
-from electrum.wallet import CannotBumpFee, CannotDoubleSpendTx
+from electrum.wallet import CannotBumpFee, CannotCPFP, CannotDoubleSpendTx
 from electrum.transaction import Transaction, PartialTransaction
 from electrum.network import NetworkException
 
@@ -37,6 +37,7 @@ Builder.load_string('''
     can_sign: False
     can_broadcast: False
     can_rbf: False
+    can_cpfp: False
     fee_str: ''
     feerate_str: ''
     date_str: ''
@@ -145,6 +146,7 @@ class TxDialog(Factory.Popup):
         self.description = tx_details.label
         self.can_broadcast = tx_details.can_broadcast
         self.can_rbf = tx_details.can_bump
+        self.can_cpfp = tx_details.can_cpfp
         self.can_dscancel = tx_details.can_dscancel
         self.tx_hash = tx_details.txid or ''
         if tx_mined_status.timestamp:
@@ -192,6 +194,7 @@ class TxDialog(Factory.Popup):
             ActionButtonOption(text=_('Sign'), func=lambda btn: self.do_sign(), enabled=self.can_sign),
             ActionButtonOption(text=_('Broadcast'), func=lambda btn: self.do_broadcast(), enabled=self.can_broadcast),
             ActionButtonOption(text=_('Bump fee'), func=lambda btn: self.do_rbf(), enabled=self.can_rbf),
+            ActionButtonOption(text=_('Child pays\nfor parent'), func=lambda btn: self.do_cpfp(), enabled=(not self.can_rbf and self.can_cpfp)),
             ActionButtonOption(text=_('Cancel') + '\n(double-spend)', func=lambda btn: self.do_dscancel(), enabled=self.can_dscancel),
             ActionButtonOption(text=_('Remove'), func=lambda btn: self.remove_local_tx(), enabled=self.can_remove_tx),
         )
@@ -250,6 +253,40 @@ class TxDialog(Factory.Popup):
         self.update()
         self.do_sign()
 
+    def do_cpfp(self):
+        from .cpfp_dialog import CPFPDialog
+        parent_tx = self.tx
+        new_tx = self.wallet.cpfp(parent_tx, 0)
+        total_size = parent_tx.estimated_size() + new_tx.estimated_size()
+        parent_txid = parent_tx.txid()
+        assert parent_txid
+        parent_fee = self.wallet.get_tx_fee(parent_txid)
+        if parent_fee is None:
+            self.app.show_error(_("Can't CPFP: unknown fee for parent transaction."))
+            return
+        cb = partial(self._do_cpfp, parent_tx=parent_tx)
+        d = CPFPDialog(self.app, parent_fee, total_size, new_tx=new_tx, callback=cb)
+        d.open()
+
+    def _do_cpfp(
+            self,
+            fee,
+            max_fee,
+            *,
+            parent_tx: Transaction,
+    ):
+        if fee is None:
+            return  # fee left empty, treat is as "cancel"
+        if fee > max_fee:
+            self.show_error(_('Max fee exceeded'))
+            return
+        try:
+            new_tx = self.wallet.cpfp(parent_tx, fee)
+        except CannotCPFP as e:
+            self.app.show_error(str(e))
+            return
+        self.app.tx_dialog(new_tx)
+
     def do_dscancel(self):
         from .dscancel_dialog import DSCancelDialog
         tx = self.tx