wizard hww: scan devices fewer times and move away from GUI thread

electrum/base_wizard.py

@@ -348,7 +348,7 @@ class BaseWizard(Logger):
         assert isinstance(self.plugin, HW_PluginBase)
         devmgr = self.plugins.device_manager
         try:
-            self.plugin.setup_device(device_info, self, purpose)
+            client = self.plugin.setup_device(device_info, self, purpose)
         except OSError as e:
             self.show_error(_('We encountered an error while connecting to your device:')
                             + '\n' + str(e) + '\n'
@@ -376,19 +376,18 @@ class BaseWizard(Logger):
             self.show_error(str(e))
             self.choose_hw_device(purpose, storage=storage)
             return
+
         if purpose == HWD_SETUP_NEW_WALLET:
             def f(derivation, script_type):
                 derivation = normalize_bip32_derivation(derivation)
                 self.run('on_hw_derivation', name, device_info, derivation, script_type)
             self.derivation_and_script_type_dialog(f)
         elif purpose == HWD_SETUP_DECRYPT_WALLET:
-            client = devmgr.client_by_id(device_info.device.id_)
             password = client.get_password_for_storage_encryption()
             try:
                 storage.decrypt(password)
             except InvalidPassword:
                 # try to clear session so that user can type another passphrase
-                client = devmgr.client_by_id(device_info.device.id_)
                 if hasattr(client, 'clear_session'):  # FIXME not all hw wallet plugins have this
                     client.clear_session()
                 raise
@@ -435,7 +434,7 @@ class BaseWizard(Logger):
         assert isinstance(self.plugin, HW_PluginBase)
         try:
             xpub = self.plugin.get_xpub(device_info.device.id_, derivation, xtype, self)
-            client = devmgr.client_by_id(device_info.device.id_)
+            client = devmgr.client_by_id(device_info.device.id_, scan_now=False)
             if not client: raise Exception("failed to find client for device id")
             root_fingerprint = client.request_root_fingerprint_from_device()
             label = client.label()  # use this as device_info.label might be outdated!

electrum/plugin.py

@@ -401,7 +401,7 @@ class DeviceMgr(ThreadJob):
     def create_client(self, device: 'Device', handler: Optional['HardwareHandlerBase'],
                       plugin: 'HW_PluginBase') -> Optional['HardwareClientBase']:
         # Get from cache first
-        client = self.client_lookup(device.id_)
+        client = self._client_by_id(device.id_)
         if client:
             return client
         client = plugin.create_client(device, handler)
@@ -437,7 +437,7 @@ class DeviceMgr(ThreadJob):
             self._close_client(id_)
 
     def _close_client(self, id_):
-        client = self.client_lookup(id_)
+        client = self._client_by_id(id_)
         self.clients.pop(client, None)
         if client:
             client.close()
@@ -446,19 +446,20 @@ class DeviceMgr(ThreadJob):
         with self.lock:
             self.xpub_ids[xpub] = id_
 
-    def client_lookup(self, id_) -> Optional['HardwareClientBase']:
+    def _client_by_id(self, id_) -> Optional['HardwareClientBase']:
         with self.lock:
             for client, (path, client_id) in self.clients.items():
                 if client_id == id_:
                     return client
         return None
 
-    def client_by_id(self, id_) -> Optional['HardwareClientBase']:
+    def client_by_id(self, id_, *, scan_now: bool = True) -> Optional['HardwareClientBase']:
         '''Returns a client for the device ID if one is registered.  If
         a device is wiped or in bootloader mode pairing is impossible;
         in such cases we communicate by device ID and not wallet.'''
-        self.scan_devices()
-        return self.client_lookup(id_)
+        if scan_now:
+            self.scan_devices()
+        return self._client_by_id(id_)
 
     @with_scan_lock
     def client_for_keystore(self, plugin: 'HW_PluginBase', handler: Optional['HardwareHandlerBase'],
@@ -495,7 +496,7 @@ class DeviceMgr(ThreadJob):
     def client_by_xpub(self, plugin: 'HW_PluginBase', xpub, handler: 'HardwareHandlerBase',
                        devices: Sequence['Device']) -> Optional['HardwareClientBase']:
         _id = self.xpub_id(xpub)
-        client = self.client_lookup(_id)
+        client = self._client_by_id(_id)
         if client:
             # An unpaired client might have another wallet's handler
             # from a prior scan.  Replace to fix dialog parenting.
@@ -511,7 +512,7 @@ class DeviceMgr(ThreadJob):
         # The wallet has not been previously paired, so let the user
         # choose an unpaired device and compare its first address.
         xtype = bip32.xpub_type(xpub)
-        client = self.client_lookup(info.device.id_)
+        client = self._client_by_id(info.device.id_)
         if client and client.is_pairable():
             # See comment above for same code
             client.handler = handler

electrum/plugins/coldcard/coldcard.py

@@ -524,6 +524,7 @@ class ColdcardPlugin(HW_PluginBase):
     def setup_device(self, device_info, wizard, purpose):
         device_id = device_info.device.id_
         client = self.scan_and_create_client_for_device(device_id=device_id, wizard=wizard)
+        return client
 
     def get_xpub(self, device_id, derivation, xtype, wizard):
         # this seems to be part of the pairing process only, not during normal ops?

electrum/plugins/digitalbitbox/digitalbitbox.py

@@ -705,6 +705,7 @@ class DigitalBitboxPlugin(HW_PluginBase):
             client.setupRunning = True
         wizard.run_task_without_blocking_gui(
             task=lambda: client.get_xpub("m/44'/0'", 'standard'))
+        return client
 
 
     def is_mobile_paired(self):

electrum/plugins/hw_wallet/plugin.py

@@ -25,6 +25,7 @@
 # SOFTWARE.
 
 from typing import TYPE_CHECKING, Dict, List, Union, Tuple, Sequence, Optional, Type
+from functools import partial
 
 from electrum.plugin import BasePlugin, hook, Device, DeviceMgr, DeviceInfo
 from electrum.i18n import _
@@ -67,14 +68,15 @@ class HW_PluginBase(BasePlugin):
 
     def scan_and_create_client_for_device(self, *, device_id: str, wizard: 'BaseWizard') -> 'HardwareClientBase':
         devmgr = self.device_manager()
-        client = devmgr.client_by_id(device_id)
+        client = wizard.run_task_without_blocking_gui(
+            task=partial(devmgr.client_by_id, device_id))
         if client is None:
             raise UserFacingException(_('Failed to create a client for this device.') + '\n' +
                                       _('Make sure it is in the correct state.'))
         client.handler = self.create_handler(wizard)
         return client
 
-    def setup_device(self, device_info: DeviceInfo, wizard: 'BaseWizard', purpose):
+    def setup_device(self, device_info: DeviceInfo, wizard: 'BaseWizard', purpose) -> 'HardwareClientBase':
         """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.

electrum/plugins/keepkey/keepkey.py

@@ -283,6 +283,7 @@ class KeepKeyPlugin(HW_PluginBase):
         wizard.run_task_without_blocking_gui(
             task=lambda: client.get_xpub("m", 'standard'))
         client.used()
+        return client
 
     def get_xpub(self, device_id, derivation, xtype, wizard):
         if xtype not in self.SUPPORTED_XTYPES:

electrum/plugins/ledger/ledger.py

@@ -610,6 +610,7 @@ class LedgerPlugin(HW_PluginBase):
         client = self.scan_and_create_client_for_device(device_id=device_id, wizard=wizard)
         wizard.run_task_without_blocking_gui(
             task=lambda: client.get_xpub("m/44'/0'", 'standard'))  # TODO replace by direct derivation once Nano S > 1.1
+        return client
 
     def get_xpub(self, device_id, derivation, xtype, wizard):
         if xtype not in self.SUPPORTED_XTYPES:

electrum/plugins/safe_t/safe_t.py

@@ -257,6 +257,7 @@ class SafeTPlugin(HW_PluginBase):
         wizard.run_task_without_blocking_gui(
             task=lambda: client.get_xpub("m", 'standard'))
         client.used()
+        return client
 
     def get_xpub(self, device_id, derivation, xtype, wizard):
         if xtype not in self.SUPPORTED_XTYPES:

electrum/plugins/trezor/trezor.py

@@ -288,6 +288,7 @@ class TrezorPlugin(HW_PluginBase):
         wizard.run_task_without_blocking_gui(
             task=lambda: client.get_xpub('m', 'standard', creating=is_creating_wallet))
         client.used()
+        return client
 
     def get_xpub(self, device_id, derivation, xtype, wizard):
         if xtype not in self.SUPPORTED_XTYPES: