egis_etu905: Handle cancel as part of the device SSM return

Cancelling an operation does allow the driver to do perform async ops
at the moment, but rather we are supposed to just send the the cancel
commands while another action may running.

So we should handle this as part of the SSM final stage, if cancellation
happened.

libfprint/drivers/egismoc/egis_etu905.c

@@ -72,10 +72,13 @@ typedef struct egis_etu905_enroll_print
   int      stage;
 } EnrollPrint;
 
-static void egis_etu905_identify_send_cancel_result_cb (FpDevice *device,
-                                                        guchar   *buffer_in,
-                                                        gsize     length_in,
-                                                        GError   *error);
+static void egis_etu905_exec_cmd_full (FpDevice         *device,
+                                       const guchar     *cmd,
+                                       gsize             cmd_length,
+                                       SynCmdMsgCallback callback,
+                                       GCancellable     *cancellable);
+
+static void egis_etu905_cancel (FpDevice *device);
 
 static void
 egis_etu905_finger_on_sensor_cb (FpiUsbTransfer *transfer,
@@ -164,11 +167,30 @@ egis_etu905_validate_response_suffix (const guchar *buffer_in,
   return result;
 }
 
+static gboolean
+egis_etu905_maybe_cancel (FpDevice *device,
+                          GError   *error)
+{
+  FpiDeviceAction action = fpi_device_get_current_action (device);
+
+  if (!fpi_device_action_is_cancelled (device) &&
+      !g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
+    return FALSE;
+
+  if (action != FPI_DEVICE_ACTION_ENROLL &&
+      action != FPI_DEVICE_ACTION_IDENTIFY)
+    return FALSE;
+
+  egis_etu905_cancel (device);
+  return TRUE;
+}
+
 static void
 egis_etu905_task_ssm_done (FpiSsm   *ssm,
                            FpDevice *device,
                            GError   *error)
 {
+  g_autoptr(GError) task_error = g_steal_pointer (&error);
   FpiDeviceEgisEtu905 *self = FPI_DEVICE_EGIS_ETU905 (device);
 
   fp_dbg ("Task SSM done");
@@ -179,8 +201,14 @@ egis_etu905_task_ssm_done (FpiSsm   *ssm,
 
   g_clear_pointer (&self->enrolled_ids, g_ptr_array_unref);
 
-  if (error)
-    fpi_device_action_error (device, error);
+  /* On cancellation we need to send the device-side cancel command before
+   * reporting the error, as the idle ->cancel vfunc may not be called due
+   * to the operation already being completed by the cancellable abort. */
+  if (egis_etu905_maybe_cancel (device, task_error))
+    return;
+
+  if (task_error)
+    fpi_device_action_error (device, g_steal_pointer (&task_error));
 }
 
 static void
@@ -1643,6 +1671,24 @@ egis_etu905_close (FpDevice *device)
   fpi_device_close_complete (device, g_steal_pointer (&error));
 }
 
+static void
+egis_etu905_cancel_cb (FpDevice *device,
+                       guchar   *buffer_in,
+                       gsize     length_in,
+                       GError   *error)
+{
+  if (error)
+    {
+      g_warning ("Cancel command failed: %s", error->message);
+      g_clear_error (&error);
+    }
+
+  error = g_error_new_literal (G_IO_ERROR, G_IO_ERROR_CANCELLED,
+                               "Operation was cancelled");
+
+  fpi_device_action_error (device, g_steal_pointer (&error));
+}
+
 static void
 egis_etu905_cancel (FpDevice *device)
 {
@@ -1661,7 +1707,7 @@ egis_etu905_cancel (FpDevice *device)
       egis_etu905_exec_cmd_full (device,
                                  cmd_enroll_discard,
                                  G_N_ELEMENTS (cmd_enroll_discard),
-                                 NULL,
+                                 egis_etu905_cancel_cb,
                                  NULL);
     }
   else if (action == FPI_DEVICE_ACTION_IDENTIFY)
@@ -1669,9 +1715,13 @@ egis_etu905_cancel (FpDevice *device)
       egis_etu905_exec_cmd_full (device,
                                  cmd_identify_cancel,
                                  G_N_ELEMENTS (cmd_identify_cancel),
-                                 NULL,
+                                 egis_etu905_cancel_cb,
                                  NULL);
     }
+  else
+    {
+      g_warning ("Cancel called for unsupported action %d", action);
+    }
 }
 
 static void
@@ -1697,7 +1747,6 @@ fpi_device_egis_etu905_class_init (FpiDeviceEgisEtu905Class *klass)
   dev_class->probe = egis_etu905_probe;
   dev_class->open = egis_etu905_open;
   dev_class->close = egis_etu905_close;
-  dev_class->cancel = egis_etu905_cancel;
   dev_class->identify = egis_etu905_identify;
   dev_class->enroll = egis_etu905_enroll;
   dev_class->delete = egis_etu905_delete;