virtual-device: Make cancellation support toggable

We may want to have the device to sleep while releasing an operation,
this will allow to do it.

libfprint/drivers/virtual-device-private.h

@@ -80,6 +80,7 @@ struct _FpDeviceVirtualDevice
   guint                    wait_command_id;
   guint                    sleep_timeout_id;
   guint                    enroll_stages_passed;
+  gboolean                 supports_cancellation;
 };
 
 /* Not really final here, but we can do this to share the FpDeviceVirtualDevice

libfprint/drivers/virtual-device.c

@@ -43,6 +43,7 @@ G_DEFINE_TYPE (FpDeviceVirtualDevice, fpi_device_virtual_device, FP_TYPE_DEVICE)
 #define SLEEP_CMD_PREFIX "SLEEP "
 #define SET_ENROLL_STAGES_PREFIX "SET_ENROLL_STAGES "
 #define SET_SCAN_TYPE_PREFIX "SET_SCAN_TYPE "
+#define SET_CANCELLATION_PREFIX "SET_CANCELLATION_ENABLED "
 
 #define LIST_CMD "LIST"
 #define UNPLUG_CMD "UNPLUG"
@@ -257,6 +258,14 @@ recv_instruction_cb (GObject      *source_object,
           else
             g_warning ("Scan type '%s' not found", scan_type);
         }
+      else if (g_str_has_prefix (cmd, SET_CANCELLATION_PREFIX))
+        {
+          self->supports_cancellation = g_ascii_strtoull (
+            cmd + strlen (SET_CANCELLATION_PREFIX), NULL, 10) != 0;
+
+          g_debug ("Cancellation support toggled: %d",
+                   self->supports_cancellation);
+        }
       else
         {
           g_ptr_array_add (self->pending_commands, g_steal_pointer (&cmd));
@@ -471,6 +480,9 @@ dev_cancel (FpDevice *dev)
 {
   FpDeviceVirtualDevice *self = FP_DEVICE_VIRTUAL_DEVICE (dev);
 
+  if (!self->supports_cancellation)
+    return;
+
   g_debug ("Got cancellation!");
   g_clear_handle_id (&self->sleep_timeout_id, g_source_remove);
 
@@ -505,6 +517,7 @@ fpi_device_virtual_device_finalize (GObject *object)
 static void
 fpi_device_virtual_device_init (FpDeviceVirtualDevice *self)
 {
+  self->supports_cancellation = TRUE;
   self->pending_commands = g_ptr_array_new_with_free_func (g_free);
 }
 

tests/virtual-device.py

@@ -96,7 +96,8 @@ class VirtualDevice(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'])
+            'FINGER', 'UNPLUG', 'SLEEP', 'SET_ENROLL_STAGES', 'SET_SCAN_TYPE',
+            'SET_CANCELLATION_ENABLED'])
 
         with Connection(self.sockaddr) as con:
             params = ' '.join(str(p) for p in args)
@@ -453,6 +454,43 @@ class VirtualDevice(unittest.TestCase):
         while not timeout_reached:
             ctx.iteration(False)
 
+        self.assertFalse(self._verify_completed)
+
+        timeout_reached = False
+        self._cancellable.cancel()
+        GLib.timeout_add(200, on_timeout)
+
+        while not timeout_reached:
+            ctx.iteration(False)
+
+        self.assertTrue(self._verify_completed)
+        self.cancel_verify()
+
+    def test_device_sleep_on_cancellation(self):
+        timeout_reached = False
+        def on_timeout():
+            nonlocal timeout_reached
+            timeout_reached = True
+
+        self.send_command('SET_CANCELLATION_ENABLED', int(False))
+        self.send_command('SLEEP', 1500)
+        self.send_command('SCAN', 'foo-print')
+        GLib.timeout_add(300, on_timeout)
+
+        self.start_verify(FPrint.Print.new(self.dev),
+            identify=self.dev.supports_identify())
+        while not timeout_reached:
+            ctx.iteration(False)
+
+        self.assertFalse(self._verify_completed)
+
+        timeout_reached = False
+        self._cancellable.cancel()
+        GLib.timeout_add(300, on_timeout)
+
+        while not timeout_reached:
+            ctx.iteration(False)
+
         self.assertFalse(self._verify_completed)
         self.cancel_verify()