hw wallets: introduce HardwareHandlerBase

previously, client.handler was sometimes
- an InstallWizard
- a QtHandlerBase where win was an ElectrumWindow
- a QtHandlerBase where win was an InstallWizard
- a CmdLineHandler

That's just too much dynamic untyped undocumented polymorphism...
Now it will never be an InstallWizard (replaced with QtHandlerBase where win is an InstallWizard),
and now in all cases client.handler is an instance of HardwareHandlerBase, yay.

related: #6063

electrum/base_wizard.py

@@ -535,6 +535,7 @@ class BaseWizard(Logger):
         if self.wallet_type == 'standard' and isinstance(self.keystores[0], Hardware_KeyStore):
             # offer encrypting with a pw derived from the hw device
             k = self.keystores[0]  # type: Hardware_KeyStore
+            assert isinstance(self.plugin, HW_PluginBase)
             try:
                 k.handler = self.plugin.create_handler(self)
                 password = k.get_password_for_storage_encryption()

electrum/gui/qt/installwizard.py

@@ -358,10 +358,6 @@ class InstallWizard(QDialog, MessageBoxMixin, BaseWizard):
 
         return db
 
-    def finished(self):
-        """Called in hardware client wrapper, in order to close popups."""
-        return
-
     def on_error(self, exc_info):
         if not isinstance(exc_info[1], UserCancelled):
             self.logger.error("on_error", exc_info=exc_info)

electrum/keystore.py

@@ -48,7 +48,7 @@ from .logging import Logger
 
 if TYPE_CHECKING:
     from .gui.qt.util import TaskThread
-    from .plugins.hw_wallet import HW_PluginBase, HardwareClientBase
+    from .plugins.hw_wallet import HW_PluginBase, HardwareClientBase, HardwareHandlerBase
 
 
 class KeyStore(Logger, ABC):
@@ -723,7 +723,7 @@ class Hardware_KeyStore(Xpub, KeyStore):
         # device reconnects
         self.xpub = d.get('xpub')
         self.label = d.get('label')
-        self.handler = None
+        self.handler = None  # type: Optional[HardwareHandlerBase]
         run_hook('init_keystore', self)
 
     def set_label(self, label):

electrum/plugin.py

@@ -39,7 +39,7 @@ from .simple_config import SimpleConfig
 from .logging import get_logger, Logger
 
 if TYPE_CHECKING:
-    from .plugins.hw_wallet import HW_PluginBase, HardwareClientBase
+    from .plugins.hw_wallet import HW_PluginBase, HardwareClientBase, HardwareHandlerBase
     from .keystore import Hardware_KeyStore
 
 
@@ -386,7 +386,8 @@ class DeviceMgr(ThreadJob):
     def register_enumerate_func(self, func):
         self.enumerate_func.add(func)
 
-    def create_client(self, device: 'Device', handler, plugin: 'HW_PluginBase') -> Optional['HardwareClientBase']:
+    def create_client(self, device: 'Device', handler: Optional['HardwareHandlerBase'],
+                      plugin: 'HW_PluginBase') -> Optional['HardwareClientBase']:
         # Get from cache first
         client = self.client_lookup(device.id_)
         if client:
@@ -447,7 +448,8 @@ class DeviceMgr(ThreadJob):
         self.scan_devices()
         return self.client_lookup(id_)
 
-    def client_for_keystore(self, plugin: 'HW_PluginBase', handler, keystore: 'Hardware_KeyStore',
+    def client_for_keystore(self, plugin: 'HW_PluginBase', handler: Optional['HardwareHandlerBase'],
+                            keystore: 'Hardware_KeyStore',
                             force_pair: bool) -> Optional['HardwareClientBase']:
         self.logger.info("getting client for keystore")
         if handler is None:
@@ -468,7 +470,7 @@ class DeviceMgr(ThreadJob):
         self.logger.info("end client for keystore")
         return client
 
-    def client_by_xpub(self, plugin: 'HW_PluginBase', xpub, handler,
+    def client_by_xpub(self, plugin: 'HW_PluginBase', xpub, handler: 'HardwareHandlerBase',
                        devices: Iterable['Device']) -> Optional['HardwareClientBase']:
         _id = self.xpub_id(xpub)
         client = self.client_lookup(_id)
@@ -482,7 +484,7 @@ class DeviceMgr(ThreadJob):
             if device.id_ == _id:
                 return self.create_client(device, handler, plugin)
 
-    def force_pair_xpub(self, plugin: 'HW_PluginBase', handler,
+    def force_pair_xpub(self, plugin: 'HW_PluginBase', handler: 'HardwareHandlerBase',
                         info: 'DeviceInfo', xpub, derivation) -> Optional['HardwareClientBase']:
         # The wallet has not been previously paired, so let the user
         # choose an unpaired device and compare its first address.
@@ -510,7 +512,8 @@ class DeviceMgr(ThreadJob):
               'its seed (and passphrase, if any).  Otherwise all bitcoins you '
               'receive will be unspendable.').format(plugin.device))
 
-    def unpaired_device_infos(self, handler, plugin: 'HW_PluginBase', devices: List['Device'] = None,
+    def unpaired_device_infos(self, handler: Optional['HardwareHandlerBase'], plugin: 'HW_PluginBase',
+                              devices: List['Device'] = None,
                               include_failing_clients=False) -> List['DeviceInfo']:
         '''Returns a list of DeviceInfo objects: one for each connected,
         unpaired device accepted by the plugin.'''
@@ -539,7 +542,7 @@ class DeviceMgr(ThreadJob):
 
         return infos
 
-    def select_device(self, plugin: 'HW_PluginBase', handler,
+    def select_device(self, plugin: 'HW_PluginBase', handler: 'HardwareHandlerBase',
                       keystore: 'Hardware_KeyStore', devices: List['Device'] = None) -> 'DeviceInfo':
         '''Ask the user to select a device to use if there is more than one,
         and return the DeviceInfo for the device.'''
@@ -581,8 +584,9 @@ class DeviceMgr(ThreadJob):
         info = infos[c]
         # save new label
         keystore.set_label(info.label)
-        if handler.win.wallet is not None:
+        wallet = handler.get_wallet()
-            handler.win.wallet.save_keystore()
+        if wallet is not None:
+            wallet.save_keystore()
         return info
 
     def _scan_devices_with_hid(self) -> List['Device']:

electrum/plugins/coldcard/cmdline.py

@@ -2,13 +2,15 @@ from electrum.plugin import hook
 from electrum.util import print_msg, raw_input, print_stderr
 from electrum.logging import get_logger
 
+from ..hw_wallet.cmdline import CmdLineHandler
+
 from .coldcard import ColdcardPlugin
 
 
 _logger = get_logger(__name__)
 
 
-class ColdcardCmdLineHandler:
+class ColdcardCmdLineHandler(CmdLineHandler):
 
     def get_passphrase(self, msg, confirm):
         raise NotImplementedError

electrum/plugins/hw_wallet/__init__.py

@@ -1,2 +1,2 @@
-from .plugin import HW_PluginBase, HardwareClientBase
+from .plugin import HW_PluginBase, HardwareClientBase, HardwareHandlerBase
 from .cmdline import CmdLineHandler

electrum/plugins/hw_wallet/cmdline.py

@@ -1,11 +1,13 @@
 from electrum.util import print_stderr, raw_input
 from electrum.logging import get_logger
 
+from .plugin import HardwareHandlerBase
+
 
 _logger = get_logger(__name__)
 
 
-class CmdLineHandler:
+class CmdLineHandler(HardwareHandlerBase):
 
     def get_passphrase(self, msg, confirm):
         import getpass

electrum/plugins/hw_wallet/plugin.py

@@ -37,6 +37,7 @@ from electrum.keystore import Xpub, Hardware_KeyStore
 
 if TYPE_CHECKING:
     from electrum.wallet import Abstract_Wallet
+    from electrum.base_wizard import BaseWizard
 
 
 class HW_PluginBase(BasePlugin):
@@ -63,7 +64,7 @@ class HW_PluginBase(BasePlugin):
             if isinstance(keystore, self.keystore_class):
                 self.device_manager().unpair_xpub(keystore.xpub)
 
-    def setup_device(self, device_info, wizard, purpose):
+    def setup_device(self, device_info, wizard: 'BaseWizard', purpose):
         """Called when creating a new wallet or when using the device to decrypt
         an existing wallet. Select the device to use.  If the device is
         uninitialized, go through the initialization process.
@@ -139,15 +140,23 @@ class HW_PluginBase(BasePlugin):
     def is_outdated_fw_ignored(self) -> bool:
         return self._ignore_outdated_fw
 
-    def create_client(self, device: 'Device', handler) -> Optional['HardwareClientBase']:
+    def create_client(self, device: 'Device',
+                      handler: Optional['HardwareHandlerBase']) -> Optional['HardwareClientBase']:
         raise NotImplementedError()
 
-    def get_xpub(self, device_id, derivation: str, xtype, wizard) -> str:
+    def get_xpub(self, device_id, derivation: str, xtype, wizard: 'BaseWizard') -> str:
+        raise NotImplementedError()
+
+    def create_handler(self, window) -> 'HardwareHandlerBase':
+        # note: in Qt GUI, 'window' is either an ElectrumWindow or an InstallWizard
         raise NotImplementedError()
 
 
 class HardwareClientBase:
 
+    plugin: 'HW_PluginBase'
+    handler: Optional['HardwareHandlerBase']
+
     def is_pairable(self) -> bool:
         raise NotImplementedError()
 
@@ -191,6 +200,41 @@ class HardwareClientBase:
         return password
 
 
+class HardwareHandlerBase:
+    """An interface between the GUI and the device handling logic for handling I/O."""
+    win = None
+    device: str
+
+    def get_wallet(self) -> Optional['Abstract_Wallet']:
+        if self.win is not None:
+            if hasattr(self.win, 'wallet'):
+                return self.win.wallet
+
+    def update_status(self, paired: bool) -> None:
+        pass
+
+    def query_choice(self, msg: str, labels: Sequence[str]) -> Optional[int]:
+        raise NotImplementedError()
+
+    def yes_no_question(self, msg: str) -> bool:
+        raise NotImplementedError()
+
+    def show_message(self, msg: str, on_cancel=None) -> None:
+        raise NotImplementedError()
+
+    def show_error(self, msg: str, blocking: bool = False) -> None:
+        raise NotImplementedError()
+
+    def finished(self) -> None:
+        pass
+
+    def get_word(self, msg: str) -> str:
+        raise NotImplementedError()
+
+    def get_passphrase(self, msg: str, confirm: bool) -> Optional[str]:
+        raise NotImplementedError()
+
+
 def is_any_tx_output_on_change_branch(tx: PartialTransaction) -> bool:
     return any([txout.is_change for txout in tx.outputs()])
 

electrum/plugins/hw_wallet/qt.py

@@ -35,13 +35,14 @@ from electrum.gui.qt.password_dialog import PasswordLayout, PW_PASSPHRASE
 from electrum.gui.qt.util import (read_QIcon, WWLabel, OkButton, WindowModalDialog,
                                   Buttons, CancelButton, TaskThread, char_width_in_lineedit)
 from electrum.gui.qt.main_window import StatusBarButton, ElectrumWindow
+from electrum.gui.qt.installwizard import InstallWizard
 
 from electrum.i18n import _
 from electrum.logging import Logger
 from electrum.util import parse_URI, InvalidBitcoinURI, UserCancelled
 from electrum.plugin import hook, DeviceUnpairableError
 
-from .plugin import OutdatedHwFirmwareException, HW_PluginBase
+from .plugin import OutdatedHwFirmwareException, HW_PluginBase, HardwareHandlerBase
 
 if TYPE_CHECKING:
     from electrum.wallet import Abstract_Wallet
@@ -50,7 +51,7 @@ if TYPE_CHECKING:
 
 # The trickiest thing about this handler was getting windows properly
 # parented on macOS.
-class QtHandlerBase(QObject, Logger):
+class QtHandlerBase(HardwareHandlerBase, QObject, Logger):
     '''An interface between the GUI (here, QT) and the device handling
     logic for handling I/O.'''
 
@@ -63,7 +64,7 @@ class QtHandlerBase(QObject, Logger):
     yes_no_signal = pyqtSignal(object)
     status_signal = pyqtSignal(object)
 
-    def __init__(self, win, device):
+    def __init__(self, win: Union[ElectrumWindow, InstallWizard], device: str):
         QObject.__init__(self)
         Logger.__init__(self)
         self.clear_signal.connect(self.clear_dialog)
@@ -267,5 +268,5 @@ class QtPluginBase(object):
         dev_name = f"{plugin.device} ({keystore.label})"
         receive_address_e.addButton("eye1.png", show_address, _("Show on {}").format(dev_name))
 
-    def create_handler(self, window: ElectrumWindow) -> 'QtHandlerBase':
+    def create_handler(self, window: Union[ElectrumWindow, InstallWizard]) -> 'QtHandlerBase':
         raise NotImplementedError()

electrum/plugins/keepkey/keepkey.py

@@ -282,7 +282,6 @@ class KeepKeyPlugin(HW_PluginBase):
         if client is None:
             raise UserFacingException(_('Failed to create a client for this device.') + '\n' +
                                       _('Make sure it is in the correct state.'))
-        # fixme: we should use: client.handler = wizard
         client.handler = self.create_handler(wizard)
         if not device_info.initialized:
             self.initialize_device(device_id, wizard, client.handler)
@@ -294,7 +293,7 @@ class KeepKeyPlugin(HW_PluginBase):
             raise ScriptTypeNotSupported(_('This type of script is not supported with {}.').format(self.device))
         devmgr = self.device_manager()
         client = devmgr.client_by_id(device_id)
-        client.handler = wizard
+        client.handler = self.create_handler(wizard)
         xpub = client.get_xpub(derivation, xtype)
         client.used()
         return xpub

electrum/plugins/keepkey/qt.py

@@ -195,9 +195,6 @@ class QtPlugin(QtPluginBase):
     #   icon_file
     #   pin_matrix_widget_class
 
-    def create_handler(self, window):
-        return QtHandler(window, self.pin_matrix_widget_class(), self.device)
-
     @only_hook_if_libraries_available
     @hook
     def receive_menu(self, menu, addrs, wallet):
@@ -302,6 +299,9 @@ class Plugin(KeepKeyPlugin, QtPlugin):
     icon_paired = "keepkey.png"
     icon_unpaired = "keepkey_unpaired.png"
 
+    def create_handler(self, window):
+        return QtHandler(window, self.pin_matrix_widget_class(), self.device)
+
     @classmethod
     def pin_matrix_widget_class(self):
         from keepkeylib.qt.pinmatrix import PinMatrixWidget

electrum/plugins/safe_t/qt.py

@@ -71,9 +71,6 @@ class QtPlugin(QtPluginBase):
     #   icon_file
     #   pin_matrix_widget_class
 
-    def create_handler(self, window):
-        return QtHandler(window, self.pin_matrix_widget_class(), self.device)
-
     @only_hook_if_libraries_available
     @hook
     def receive_menu(self, menu, addrs, wallet):
@@ -176,6 +173,9 @@ class Plugin(SafeTPlugin, QtPlugin):
     icon_unpaired = "safe-t_unpaired.png"
     icon_paired = "safe-t.png"
 
+    def create_handler(self, window):
+        return QtHandler(window, self.pin_matrix_widget_class(), self.device)
+
     @classmethod
     def pin_matrix_widget_class(self):
         from safetlib.qt.pinmatrix import PinMatrixWidget

electrum/plugins/safe_t/safe_t.py

@@ -256,7 +256,6 @@ class SafeTPlugin(HW_PluginBase):
         if client is None:
             raise UserFacingException(_('Failed to create a client for this device.') + '\n' +
                                       _('Make sure it is in the correct state.'))
-        # fixme: we should use: client.handler = wizard
         client.handler = self.create_handler(wizard)
         if not device_info.initialized:
             self.initialize_device(device_id, wizard, client.handler)
@@ -268,7 +267,7 @@ class SafeTPlugin(HW_PluginBase):
             raise ScriptTypeNotSupported(_('This type of script is not supported with {}.').format(self.device))
         devmgr = self.device_manager()
         client = devmgr.client_by_id(device_id)
-        client.handler = wizard
+        client.handler = self.create_handler(wizard)
         xpub = client.get_xpub(derivation, xtype)
         client.used()
         return xpub

electrum/plugins/trezor/qt.py

@@ -169,9 +169,6 @@ class QtPlugin(QtPluginBase):
     #   icon_file
     #   pin_matrix_widget_class
 
-    def create_handler(self, window):
-        return QtHandler(window, self.pin_matrix_widget_class(), self.device)
-
     @only_hook_if_libraries_available
     @hook
     def receive_menu(self, menu, addrs, wallet):
@@ -377,6 +374,9 @@ class Plugin(TrezorPlugin, QtPlugin):
     icon_unpaired = "trezor_unpaired.png"
     icon_paired = "trezor.png"
 
+    def create_handler(self, window):
+        return QtHandler(window, self.pin_matrix_widget_class(), self.device)
+
     @classmethod
     def pin_matrix_widget_class(self):
         from trezorlib.qt.pinmatrix import PinMatrixWidget

electrum/plugins/trezor/trezor.py

@@ -282,7 +282,6 @@ class TrezorPlugin(HW_PluginBase):
                    .format(self.device, client.label(), self.firmware_URL))
             raise OutdatedHwFirmwareException(msg)
 
-        # fixme: we should use: client.handler = wizard
         client.handler = self.create_handler(wizard)
         if not device_info.initialized:
             self.initialize_device(device_id, wizard, client.handler)
@@ -295,7 +294,7 @@ class TrezorPlugin(HW_PluginBase):
             raise ScriptTypeNotSupported(_('This type of script is not supported with {}.').format(self.device))
         devmgr = self.device_manager()
         client = devmgr.client_by_id(device_id)
-        client.handler = wizard
+        client.handler = self.create_handler(wizard)
         xpub = client.get_xpub(derivation, xtype)
         client.used()
         return xpub