Allow FpPrint data to be extended on enrollment.

* Allow FPI_PRINT_NBIS to be extended rather than overridden if a user
  supplies an existing FpPrint template with data;
* Prints will only be extended if a device has the required feature.
  For image-based devices this feature is added by default since they
  typically do not have storage (this can be overridden at the child
  class level).

Extending an existing FpPrint requires passing a template print with
existing data during the enrollment process. This is done because the
caller is responsible for maintaining the fingerprint database and doing
the necessary deserialization operations if needed. The existing
example program is updated to show how to do that.

tests/virtual-image.py

@@ -136,6 +136,7 @@ class VirtualImage(unittest.TestCase):
         self.assertTrue(self.dev.has_feature(FPrint.DeviceFeature.CAPTURE))
         self.assertTrue(self.dev.has_feature(FPrint.DeviceFeature.IDENTIFY))
         self.assertTrue(self.dev.has_feature(FPrint.DeviceFeature.VERIFY))
+        self.assertTrue(self.dev.has_feature(FPrint.DeviceFeature.UPDATE_PRINT))
         self.assertFalse(self.dev.has_feature(FPrint.DeviceFeature.DUPLICATES_CHECK))
         self.assertFalse(self.dev.has_feature(FPrint.DeviceFeature.STORAGE))
         self.assertFalse(self.dev.has_feature(FPrint.DeviceFeature.STORAGE_LIST))
@@ -144,7 +145,8 @@ class VirtualImage(unittest.TestCase):
         self.assertEqual(self.dev.get_features(),
                          FPrint.DeviceFeature.CAPTURE |
                          FPrint.DeviceFeature.IDENTIFY |
-                         FPrint.DeviceFeature.VERIFY)
+                         FPrint.DeviceFeature.VERIFY |
+                         FPrint.DeviceFeature.UPDATE_PRINT)
 
     def test_capture_prevents_close(self):
         cancel = Gio.Cancellable()
@@ -167,7 +169,7 @@ class VirtualImage(unittest.TestCase):
         while not self._cancelled:
             ctx.iteration(True)
 
-    def enroll_print(self, image):
+    def enroll_print(self, image, template=None):
         self._step = 0
         self._enrolled = None
 
@@ -181,14 +183,15 @@ class VirtualImage(unittest.TestCase):
             self.assertEqual(self.dev.get_finger_status(), FPrint.FingerStatusFlags.NONE)
             self._enrolled = fp
 
-        template = FPrint.Print.new(self.dev)
-        template.props.finger = FPrint.Finger.LEFT_THUMB
-        template.props.username = "testuser"
-        template.props.description = "test print"
-        datetime = GLib.DateTime.new_now_local()
-        date = GLib.Date()
-        date.set_dmy(*datetime.get_ymd()[::-1])
-        template.props.enroll_date = date
+        if template is None:
+            template = FPrint.Print.new(self.dev)
+            template.props.finger = FPrint.Finger.LEFT_THUMB
+            template.props.username = "testuser"
+            template.props.description = "test print"
+            datetime = GLib.DateTime.new_now_local()
+            date = GLib.Date()
+            date.set_dmy(*datetime.get_ymd()[::-1])
+            template.props.enroll_date = date
         self.assertEqual(self.dev.get_finger_status(), FPrint.FingerStatusFlags.NONE)
         self.dev.enroll(template, None, progress_cb, tuple(), done_cb)
 
@@ -264,6 +267,28 @@ class VirtualImage(unittest.TestCase):
             ctx.iteration(True)
         assert(not self._verify_match)
 
+        # Test fingerprint updates
+        # Enroll a second print
+        fp_whorl_tended_arch = self.enroll_print('tented_arch', fp_whorl)
+
+        # Make sure the first print verifies successfully after the update
+        self._verify_match = None
+        self._verify_fp = None
+        self.dev.verify(fp_whorl_tended_arch, callback=verify_cb)
+        self.send_image('whorl')
+        while self._verify_match is None:
+            ctx.iteration(True)
+        assert(self._verify_match)
+
+        # Make sure the second print verifies successfully after the update
+        self._verify_match = None
+        self._verify_fp = None
+        self.dev.verify(fp_whorl_tended_arch, callback=verify_cb)
+        self.send_image('tented_arch')
+        while self._verify_match is None:
+            ctx.iteration(True)
+        assert(self._verify_match)
+
         # Test verify error cases
         self._verify_fp = None
         self._verify_error = None