TrezorClient: should be in a separate thread

First steps; get show_address working.
Client is not responsible for showing exceptions.
Suppress uninteresting exceptions.

gui/qt/main_window.py

@@ -37,9 +37,10 @@ import icons_rc
 from electrum.bitcoin import COIN, is_valid, TYPE_ADDRESS
 from electrum.plugins import run_hook
 from electrum.i18n import _
-from electrum.util import block_explorer, block_explorer_info, block_explorer_URL
-from electrum.util import format_satoshis, format_satoshis_plain, format_time
-from electrum.util import PrintError, NotEnoughFunds, StoreDict
+from electrum.util import (block_explorer, block_explorer_info, format_time,
+                           block_explorer_URL, format_satoshis, PrintError,
+                           format_satoshis_plain, NotEnoughFunds, StoreDict,
+                           SilentException)
 from electrum import Transaction, mnemonic
 from electrum import util, bitcoin, commands
 from electrum import SimpleConfig, COIN_CHOOSERS, paymentrequest
@@ -198,8 +199,9 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, PrintError):
         self.raise_()
 
     def on_error(self, exc_info):
-        traceback.print_exception(*exc_info)
-        self.show_error(str(exc_info[1]))
+        if not isinstance(exc_info[1], SilentException):
+            traceback.print_exception(*exc_info)
+            self.show_error(str(exc_info[1]))
 
     def on_network(self, event, *args):
         if event == 'updated':
@@ -254,6 +256,7 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, PrintError):
         run_hook('close_wallet', self.wallet)
 
     def load_wallet(self, wallet):
+        wallet.thread = TaskThread(self, self.on_error)
         self.wallet = wallet
         self.update_recently_visited(wallet.storage.path)
         self.import_old_contacts()
@@ -2856,6 +2859,7 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, PrintError):
         event.accept()
 
     def clean_up(self):
+        self.wallet.thread.stop()
         if self.network:
             self.network.unregister_callback(self.on_network)
         self.config.set_key("is_maximized", self.isMaximized())

lib/util.py

@@ -21,6 +21,10 @@ class InvalidPassword(Exception):
     def __str__(self):
         return _("Incorrect password")
 
+class SilentException(Exception):
+    '''An exception that should probably be suppressed from the user'''
+    pass
+
 class MyEncoder(json.JSONEncoder):
     def default(self, obj):
         from transaction import Transaction

plugins/trezor/clientbase.py

@@ -1,7 +1,7 @@
 from sys import stderr
 
 from electrum.i18n import _
-from electrum.util import PrintError
+from electrum.util import PrintError, SilentException
 
 
 class GuiMixin(object):
@@ -20,6 +20,16 @@ class GuiMixin(object):
         'passphrase': _("Confirm on %s device to continue"),
     }
 
+    def callback_Failure(self, msg):
+        # BaseClient's unfortunate call() implementation forces us to
+        # raise exceptions on failure in order to unwind the stack.
+        # However, making the user acknowledge they cancelled
+        # gets old very quickly, so we suppress those.
+        if msg.code in (self.types.Failure_PinCancelled,
+                        self.types.Failure_ActionCancelled):
+            raise SilentException()
+        raise RuntimeError(msg.message)
+
     def callback_ButtonRequest(self, msg):
         msg_code = self.msg_code_override or msg.code
         message = self.messages.get(msg_code, self.messages['default'])
@@ -65,6 +75,7 @@ class TrezorClientBase(GuiMixin, PrintError):
         self.handler = handler
         self.hid_id_ = hid_id
         self.tx_api = plugin
+        self.types = plugin.types
         self.msg_code_override = None
 
     def __str__(self):
@@ -172,9 +183,6 @@ class TrezorClientBase(GuiMixin, PrintError):
         def wrapped(self, *args, **kwargs):
             try:
                 return func(self, *args, **kwargs)
-            except BaseException as e:
-                self.handler.show_error(str(e))
-                raise e
             finally:
                 self.handler.finished()
 

plugins/trezor/plugin.py

@@ -1,5 +1,6 @@
 import base64
 import re
+import threading
 import time
 
 from binascii import unhexlify
@@ -172,6 +173,7 @@ class TrezorCompatiblePlugin(BasePlugin, ThreadJob):
 
     def __init__(self, parent, config, name):
         BasePlugin.__init__(self, parent, config, name)
+        self.main_thread = threading.current_thread()
         self.device = self.wallet_class.device
         self.wallet_class.plugin = self
         self.prevent_timeout = time.time() + 3600 * 24 * 365
@@ -216,6 +218,8 @@ class TrezorCompatiblePlugin(BasePlugin, ThreadJob):
         return self.client_class(transport, handler, self, hid_id)
 
     def get_client(self, wallet, force_pair=True, check_firmware=True):
+        assert self.main_thread != threading.current_thread()
+
         '''check_firmware is ignored unless force_pair is True.'''
         client = self.device_manager().get_client(wallet, force_pair)
 

plugins/trezor/qt_generic.py

@@ -231,7 +231,7 @@ def qt_plugin_class(base_plugin_class):
         window.statusBar().addPermanentWidget(window.tzb)
         wallet.handler = self.create_handler(window)
         # Trigger a pairing
-        self.get_client(wallet)
+        wallet.thread.add(partial(self.get_client, wallet))
 
     def on_create_wallet(self, wallet, wizard):
         assert type(wallet) == self.wallet_class
@@ -242,8 +242,9 @@ def qt_plugin_class(base_plugin_class):
     @hook
     def receive_menu(self, menu, addrs, wallet):
         if type(wallet) == self.wallet_class and len(addrs) == 1:
-            menu.addAction(_("Show on %s") % self.device,
-                           lambda: self.show_address(wallet, addrs[0]))
+            def show_address():
+                wallet.thread.add(partial(self.show_address, wallet, addrs[0]))
+            menu.addAction(_("Show on %s") % self.device, show_address)
 
     def settings_dialog(self, window):
         hid_id = self.choose_device(window)