trezor: move the transport-related reimplemented parts into a separate module. disable the bridge transport.

The bridge transport uses requests.post, which uses socket.getaddrinfo under the hood, which on some OSes (MacOS, Windows) in CPython takes a lock. The enumerate method for the bridge transport can block for 10-30 seconds while waiting for this lock.

plugins/trezor/transport.py

@@ -0,0 +1,95 @@
+from electrum.util import PrintError
+
+
+class TrezorTransport(PrintError):
+
+    @staticmethod
+    def all_transports():
+        """Reimplemented trezorlib.transport.all_transports so that we can
+        enable/disable specific transports.
+        """
+        try:
+            # only to detect trezorlib version
+            from trezorlib.transport import all_transports
+        except ImportError:
+            # old trezorlib. compat for trezorlib < 0.9.2
+            transports = []
+            #try:
+            #    from trezorlib.transport_bridge import BridgeTransport
+            #    transports.append(BridgeTransport)
+            #except BaseException:
+            #    pass
+            try:
+                from trezorlib.transport_hid import HidTransport
+                transports.append(HidTransport)
+            except BaseException:
+                pass
+            try:
+                from trezorlib.transport_udp import UdpTransport
+                transports.append(UdpTransport)
+            except BaseException:
+                pass
+            try:
+                from trezorlib.transport_webusb import WebUsbTransport
+                transports.append(WebUsbTransport)
+            except BaseException:
+                pass
+        else:
+            # new trezorlib.
+            transports = []
+            #try:
+            #    from trezorlib.transport.bridge import BridgeTransport
+            #    transports.append(BridgeTransport)
+            #except BaseException:
+            #    pass
+            try:
+                from trezorlib.transport.hid import HidTransport
+                transports.append(HidTransport)
+            except BaseException:
+                pass
+            try:
+                from trezorlib.transport.udp import UdpTransport
+                transports.append(UdpTransport)
+            except BaseException:
+                pass
+            try:
+                from trezorlib.transport.webusb import WebUsbTransport
+                transports.append(WebUsbTransport)
+            except BaseException:
+                pass
+            return transports
+        return transports
+
+    def enumerate_devices(self):
+        """Just like trezorlib.transport.enumerate_devices,
+        but with exception catching, so that transports can fail separately.
+        """
+        devices = []
+        for transport in self.all_transports():
+            try:
+                new_devices = transport.enumerate()
+            except BaseException as e:
+                self.print_error('enumerate failed for {}. error {}'
+                                 .format(transport.__name__, str(e)))
+            else:
+                devices.extend(new_devices)
+        return devices
+
+    def get_transport(self, path=None):
+        """Reimplemented trezorlib.transport.get_transport,
+        (1) for old trezorlib
+        (2) to be able to disable specific transports
+        (3) to call our own enumerate_devices that catches exceptions
+        """
+        if path is None:
+            try:
+                return self.enumerate_devices()[0]
+            except IndexError:
+                raise Exception("No TREZOR device found") from None
+
+        def match_prefix(a, b):
+            return a.startswith(b) or b.startswith(a)
+        transports = [t for t in self.all_transports() if match_prefix(path, t.PATH_PREFIX)]
+        if transports:
+            return transports[0].find_by_path(path)
+        raise Exception("Unknown path prefix '%s'" % path)