virtual-device: Add SET_KEEP_ALIVE command, to keep the listener up

We may want to be able to talk with the device while it's closed to
queue commands to be performed once it opens (could be even a script),
so to do this we need to close the device first, send those commands and
eventually process them.

We used a trick to send an invalid command before that was ignored by
release, but having the device available is just easier to handle.

So, when keep alive is enabled we don't stop the listener when closing
but only on actual device disposition.

libfprint/drivers/virtual-device-private.h

@@ -84,6 +84,7 @@ struct _FpDeviceVirtualDevice
   gboolean                 supports_cancellation;
   gboolean                 injected_synthetic_cmd;
   gboolean                 ignore_wait;
+  gboolean                 keep_alive;
 };
 
 /* Not really final here, but we can do this to share the FpDeviceVirtualDevice

libfprint/drivers/virtual-device.c

@@ -44,6 +44,7 @@ G_DEFINE_TYPE (FpDeviceVirtualDevice, fpi_device_virtual_device, FP_TYPE_DEVICE)
 #define SET_ENROLL_STAGES_PREFIX "SET_ENROLL_STAGES "
 #define SET_SCAN_TYPE_PREFIX "SET_SCAN_TYPE "
 #define SET_CANCELLATION_PREFIX "SET_CANCELLATION_ENABLED "
+#define SET_KEEP_ALIVE_PREFIX "SET_KEEP_ALIVE "
 
 #define LIST_CMD "LIST"
 #define UNPLUG_CMD "UNPLUG"
@@ -289,6 +290,13 @@ recv_instruction_cb (GObject      *source_object,
           g_debug ("Cancellation support toggled: %d",
                    self->supports_cancellation);
         }
+      else if (g_str_has_prefix (cmd, SET_KEEP_ALIVE_PREFIX))
+        {
+          self->keep_alive = g_ascii_strtoull (
+            cmd + strlen (SET_KEEP_ALIVE_PREFIX), NULL, 10) != 0;
+
+          g_debug ("Keep alive toggled: %d", self->keep_alive);
+        }
       else
         {
           g_ptr_array_add (self->pending_commands, g_steal_pointer (&cmd));
@@ -692,6 +700,14 @@ dev_cancel (FpDevice *dev)
   maybe_continue_current_action (self);
 }
 
+static void
+stop_listener (FpDeviceVirtualDevice *self)
+{
+  g_cancellable_cancel (self->cancellable);
+  g_clear_object (&self->cancellable);
+  g_clear_object (&self->listener);
+}
+
 static void
 dev_deinit (FpDevice *dev)
 {
@@ -711,10 +727,9 @@ dev_deinit (FpDevice *dev)
 
   g_clear_handle_id (&self->wait_command_id, g_source_remove);
   g_clear_handle_id (&self->sleep_timeout_id, g_source_remove);
-  g_cancellable_cancel (self->cancellable);
-  g_clear_object (&self->cancellable);
-  g_clear_object (&self->listener);
-  g_clear_object (&self->listener);
+
+  if (!self->keep_alive)
+    stop_listener (self);
 
   fpi_device_close_complete (dev, NULL);
 }
@@ -725,6 +740,7 @@ fpi_device_virtual_device_finalize (GObject *object)
   FpDeviceVirtualDevice *self = FP_DEVICE_VIRTUAL_DEVICE (object);
 
   G_DEBUG_HERE ();
+  stop_listener (self);
   g_clear_pointer (&self->pending_commands, g_ptr_array_unref);
   G_OBJECT_CLASS (fpi_device_virtual_device_parent_class)->finalize (object);
 }

tests/virtual-device.py

@@ -123,7 +123,7 @@ class VirtualDeviceBase(unittest.TestCase):
     def send_command(self, command, *args):
         self.assertIn(command, ['INSERT', 'REMOVE', 'SCAN', 'ERROR', 'RETRY',
             'FINGER', 'UNPLUG', 'SLEEP', 'SET_ENROLL_STAGES', 'SET_SCAN_TYPE',
-            'SET_CANCELLATION_ENABLED', 'IGNORED_COMMAND'])
+            'SET_CANCELLATION_ENABLED', 'SET_KEEP_ALIVE', 'IGNORED_COMMAND'])
 
         with Connection(self.sockaddr) as con:
             params = ' '.join(str(p) for p in args)
@@ -162,6 +162,9 @@ class VirtualDeviceBase(unittest.TestCase):
         else:
             raise Exception('No known type found for {}'.format(obj))
 
+    def set_keep_alive(self, value):
+        self.send_command('SET_KEEP_ALIVE', 1 if value else 0)
+
     def send_sleep(self, interval):
         self.assertGreater(interval, 0)
         multiplier = 5 if 'UNDER_VALGRIND' in os.environ else 1
@@ -361,6 +364,17 @@ class VirtualDevice(VirtualDeviceBase):
         self.assertTrue(error.exception.matches(FPrint.DeviceError.quark(),
                                                 FPrint.DeviceError.PROTO))
 
+    def test_open_error_with_keep_alive(self):
+        self._close_on_teardown = False
+        self.set_keep_alive(True)
+        self.dev.close_sync()
+
+        self.send_error(FPrint.DeviceError.PROTO)
+        with self.assertRaises(GLib.Error) as error:
+            self.dev.open_sync()
+        self.assertTrue(error.exception.matches(FPrint.DeviceError.quark(),
+                                                FPrint.DeviceError.PROTO))
+
     def test_delayed_open(self):
         self.send_command('IGNORED_COMMAND') # This will be consumed by close
         self.send_sleep(500) # This will be consumed by open
@@ -386,6 +400,28 @@ class VirtualDevice(VirtualDeviceBase):
         while not opened:
             ctx.iteration(True)
 
+    def test_delayed_open_with_keep_alive(self):
+        self.set_keep_alive(True)
+        self.dev.close_sync()
+
+        opened = False
+        def on_opened(dev, res):
+            nonlocal opened
+            dev.open_finish(res)
+            opened = True
+
+        self.send_sleep(500)
+        self.dev.open(callback=on_opened)
+
+        self.wait_timeout(10)
+        self.assertFalse(self.dev.is_open())
+
+        self.wait_timeout(10)
+        self.assertFalse(self.dev.is_open())
+
+        while not opened:
+            ctx.iteration(True)
+
     def test_enroll(self):
         matching = self.enroll_print('testprint', FPrint.Finger.LEFT_LITTLE)
         self.assertEqual(matching.get_username(), 'testuser')
@@ -485,6 +521,7 @@ class VirtualDevice(VirtualDeviceBase):
             ctx.iteration(True)
 
         self.assertEqual(enrolled.get_driver(), self.dev.get_driver())
+        self.assertEqual(enrolled.props.fpi_data.unpack(), 'print-id')
 
     def test_enroll_script(self):
         self.send_command('SET_ENROLL_STAGES', 8)
@@ -507,6 +544,7 @@ class VirtualDevice(VirtualDeviceBase):
 
         enrolled = self.dev.enroll_sync(FPrint.Print.new(self.dev))
         self.assertEqual(enrolled.get_driver(), self.dev.get_driver())
+        self.assertEqual(enrolled.props.fpi_data.unpack(), 'print-id')
 
     def test_finger_status(self):
         self.start_verify(FPrint.Print.new(self.dev),
@@ -812,15 +850,13 @@ class VirtualDeviceBusyDeviceOperations(VirtualDeviceBase):
         super().tearDown()
 
     def test_open(self):
-        self.send_command('IGNORED_COMMAND')
-        self.send_sleep(100)
+        self.set_keep_alive(True)
 
-        with GLibErrorMessage('libfprint-virtual_device',
-            GLib.LogLevelFlags.LEVEL_WARNING, 'Could not process command: *'):
         while self.dev.is_open():
             ctx.iteration(True)
 
         self.assertFalse(self.dev.is_open())
+        self.send_sleep(100)
         self.dev.open()
         with self.assertRaises(GLib.Error) as error:
             self.dev.open_sync()