Hook up a ButtonPressRequired signal

When the nordic communication requires us to notify the user to press the
button, emit a signal and pass that up.

README.md

@@ -154,6 +154,12 @@ org.freedesktop.tuhi1.Device
 
       Returns a string representing the JSON data from the last drawings or
       the empty string if no data is available or the index is invalid.
+
+  Signal: ButtonPressRequired()
+      Sent when the user is expected to press the physical button on the
+      device. A client should display a notification in response, if the
+      user does not press the button during the (firmware-specific) timeout
+      the current operation will fail.
 ```
 
 JSON File Format

tuhi.py

@@ -75,12 +75,14 @@ class TuhiDevice(GObject.Object):
     real device) with the frontend DBusServer object that exports the device
     over Tuhi's DBus interface
     """
+
     def __init__(self, bluez_device, tuhi_dbus_device, paired=True):
         GObject.Object.__init__(self)
         self._tuhi_dbus_device = tuhi_dbus_device
         self._wacom_device = WacomDevice(bluez_device)
         self._wacom_device.connect('drawing', self._on_drawing_received)
         self._wacom_device.connect('done', self._on_fetching_finished, bluez_device)
+        self._wacom_device.connect('button-press-required', self._on_button_press_required)
         self.drawings = []
         self.paired = paired
 
@@ -139,6 +141,9 @@ class TuhiDevice(GObject.Object):
     def _on_fetching_finished(self, device, bluez_device):
         bluez_device.disconnect_device()
 
+    def _on_button_press_required(self, device):
+        self._tuhi_dbus_device.notify_button_press_required()
+
 
 class Tuhi(GObject.Object):
     __gsignals__ = {

tuhi/dbusserver.py

@@ -61,6 +61,8 @@ INTROSPECTION_XML = """
       <arg name='json' type='s' direction='out'/>
     </method>
 
+    <signal name='ButtonPressRequired' />
+
     <signal name='ListenComplete'>
        <arg name='status' type='i' />
     </signal>
@@ -162,6 +164,11 @@ class TuhiDBusDevice(GObject.Object):
     def add_drawing(self, drawing):
         self.drawings.append(drawing)
 
+    def notify_button_press_required(self):
+        logger.debug("Sending ButtonPressRequired signal")
+        self._connection.emit_signal(None, self.objpath, INTF_DEVICE,
+                                     "ButtonPressRequired", None)
+
 
 class TuhiDBusServer(GObject.Object):
     """

tuhi/wacom.py

@@ -124,6 +124,8 @@ class WacomDevice(GObject.Object):
             (GObject.SIGNAL_RUN_FIRST, None, (GObject.TYPE_PYOBJECT,)),
         "done":
             (GObject.SIGNAL_RUN_FIRST, None, ()),
+        "button-press-required":
+            (GObject.SIGNAL_RUN_FIRST, None, ()),
     }
 
     def __init__(self, device):
@@ -578,6 +580,7 @@ class WacomDevice(GObject.Object):
     def pair_device_slate(self):
         self.register_connection()
         logger.info("Press the button now to confirm")
+        self.emit('button-press-required')
         data = self.wait_nordic_data([0xe4, 0xb3], 10)
         if data.opcode == 0xb3:
             # generic ACK
@@ -604,6 +607,7 @@ class WacomDevice(GObject.Object):
         self.send_nordic_command(command=0xe3,
                                  arguments=[0x01])
         logger.info("Press the button now to confirm")
+        self.emit('button-press-required')
         # Wait for the button confirmation event, or any error
         data = self.wait_nordic_data([0xe4, 0xb3], 10)
         if data.opcode == 0xb3: