libfprint/libfprint/fpi-device.c

/*
 * FpDevice - A fingerprint reader device - Private APIs
 * Copyright (C) 2019 Benjamin Berg <bberg@redhat.com>
 * Copyright (C) 2019 Marco Trevisan <marco.trevisan@canonical.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#define FP_COMPONENT "device"
#include "fpi-log.h"

#include "fp-device-private.h"

/**
 * SECTION: fpi-device
 * @title: Internal FpDevice
 * @short_description: Internal device routines
 *
 * The methods that are available for drivers to manipulate a device. See
 * #FpDeviceClass for more information. Also note that most of these are
 * not relevant for image based devices, see #FpImageDeviceClass in that
 * case.
 *
 * Also see the public #FpDevice routines.
 */

/* Manually redefine what G_DEFINE_* macro does */
static inline gpointer
fp_device_get_instance_private (FpDevice *self)
{
  FpDeviceClass *dev_class = g_type_class_peek_static (FP_TYPE_DEVICE);

  return G_STRUCT_MEMBER_P (self,
                            g_type_class_get_instance_private_offset (dev_class));
}

/**
 * fpi_device_retry_new:
 * @error: The #FpDeviceRetry error value describing the issue
 *
 * Create a new retry error code for use with fpi_device_verify_complete()
 * and similar calls.
 */
GError *
fpi_device_retry_new (FpDeviceRetry error)
{
  const gchar *msg;

  switch (error)
    {
    case FP_DEVICE_RETRY_GENERAL:
      msg = "Please try again.";
      break;

    case FP_DEVICE_RETRY_TOO_SHORT:
      msg = "The swipe was too short, please try again.";
      break;

    case FP_DEVICE_RETRY_CENTER_FINGER:
      msg = "The finger was not centered properly, please try again.";
      break;

    case FP_DEVICE_RETRY_REMOVE_FINGER:
      msg = "Please try again after removing the finger first.";
      break;

    default:
      g_warning ("Unsupported error, returning general error instead!");
      error = FP_DEVICE_RETRY_GENERAL;
      msg = "Please try again.";
    }

  return g_error_new_literal (FP_DEVICE_RETRY, error, msg);
}

/**
 * fpi_device_error_new:
 * @error: The #FpDeviceRetry error value describing the issue
 *
 * Create a new error code for use with fpi_device_verify_complete() and
 * similar calls.
 */
GError *
fpi_device_error_new (FpDeviceError error)
{
  const gchar *msg;

  switch (error)
    {
    case FP_DEVICE_ERROR_GENERAL:
      msg = "An unspecified error occurred!";
      break;

    case FP_DEVICE_ERROR_NOT_SUPPORTED:
      msg = "The operation is not supported on this device!";
      break;

    case FP_DEVICE_ERROR_NOT_OPEN:
      msg = "The device needs to be opened first!";
      break;

    case FP_DEVICE_ERROR_ALREADY_OPEN:
      msg = "The device has already been opened!";
      break;

    case FP_DEVICE_ERROR_BUSY:
      msg = "The device is still busy with another operation, please try again later.";
      break;

    case FP_DEVICE_ERROR_PROTO:
      msg = "The driver encountered a protocol error with the device.";
      break;

    case FP_DEVICE_ERROR_DATA_INVALID:
      msg = "Passed (print) data is not valid.";
      break;

    case FP_DEVICE_ERROR_DATA_FULL:
      msg = "On device storage space is full.";
      break;

    case FP_DEVICE_ERROR_DATA_NOT_FOUND:
      msg = "Print was not found on the devices storage.";
      break;

    case FP_DEVICE_ERROR_DATA_DUPLICATE:
      msg = "This finger has already enrolled, please try a different finger";
      break;

    default:
      g_warning ("Unsupported error, returning general error instead!");
      error = FP_DEVICE_ERROR_GENERAL;
      msg = "An unspecified error occurred!";
    }

  return g_error_new_literal (FP_DEVICE_ERROR, error, msg);
}

/**
 * fpi_device_retry_new_msg:
 * @error: The #FpDeviceRetry error value describing the issue
 * @msg: Custom message to use with printf-style formatting
 * @...: args for @msg
 *
 * Create a new retry error code for use with fpi_device_verify_complete()
 * and similar calls.
 */
GError *
fpi_device_retry_new_msg (FpDeviceRetry device_error,
                          const gchar  *msg,
                          ...)
{
  GError *error;
  va_list args;

  va_start (args, msg);
  error = g_error_new_valist (FP_DEVICE_RETRY, device_error, msg, args);
  va_end (args);

  return error;
}

/**
 * fpi_device_error_new_msg:
 * @error: The #FpDeviceRetry error value describing the issue
 * @msg: Custom message to use with printf-style formatting
 * @...: args for @msg
 *
 * Create a new error code for use with fpi_device_verify_complete()
 * and similar calls.
 */
GError *
fpi_device_error_new_msg (FpDeviceError device_error,
                          const gchar  *msg,
                          ...)
{
  GError *error;
  va_list args;

  va_start (args, msg);
  error = g_error_new_valist (FP_DEVICE_ERROR, device_error, msg, args);
  va_end (args);

  return error;
}

/**
 * fpi_device_set_nr_enroll_stages:
 * @device: The #FpDevice
 * @enroll_stages: The number of enroll stages
 *
 * Updates the reported number of enroll stages that the device needs.
 * If all supported devices have the same number of stages, then the
 * value can simply be set in the class.
 */
void
fpi_device_set_nr_enroll_stages (FpDevice *device,
                                 gint      enroll_stages)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);

  g_return_if_fail (FP_IS_DEVICE (device));

  priv->nr_enroll_stages = enroll_stages;
  g_object_notify (G_OBJECT (device), "nr-enroll-stages");
}

/**
 * fpi_device_set_scan_type:
 * @device: The #FpDevice
 * @scan_type: The scan type of the device
 *
 * Updates the the scan type of the device from the default.
 * If all supported devices have the same scan type, then the
 * value can simply be set in the class.
 */
void
fpi_device_set_scan_type (FpDevice  *device,
                          FpScanType scan_type)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);

  g_return_if_fail (FP_IS_DEVICE (device));

  priv->scan_type = scan_type;
  g_object_notify (G_OBJECT (device), "scan-type");
}

typedef struct
{
  GSource   source;
  FpDevice *device;
} FpDeviceTimeoutSource;

static void
timeout_finalize (GSource *source)
{
  FpDeviceTimeoutSource *timeout_source = (FpDeviceTimeoutSource *) source;
  FpDevicePrivate *priv;

  priv = fp_device_get_instance_private (timeout_source->device);
  priv->sources = g_slist_remove (priv->sources, source);
}

static gboolean
timeout_dispatch (GSource *source, GSourceFunc gsource_func, gpointer user_data)
{
  FpDeviceTimeoutSource *timeout_source = (FpDeviceTimeoutSource *) source;
  FpTimeoutFunc callback = (FpTimeoutFunc) gsource_func;

  callback (timeout_source->device, user_data);

  return G_SOURCE_REMOVE;
}

static GSourceFuncs timeout_funcs = {
  NULL, /* prepare */
  NULL, /* check */
  timeout_dispatch,
  timeout_finalize,
  NULL, NULL
};

/**
 * fpi_device_add_timeout:
 * @device: The #FpDevice
 * @interval: The interval in milliseconds
 * @func: The #FpTimeoutFunc to call on timeout
 * @user_data: (nullable): User data to pass to the callback
 * @destroy_notify: (nullable): #GDestroyNotify for @user_data
 *
 * Register a timeout to run. Drivers should always make sure that timers are
 * cancelled when appropriate.
 *
 * Returns: (transfer none): A newly created and attached #GSource
 */
GSource *
fpi_device_add_timeout (FpDevice      *device,
                        gint           interval,
                        FpTimeoutFunc  func,
                        gpointer       user_data,
                        GDestroyNotify destroy_notify)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);
  FpDeviceTimeoutSource *source;

  source = (FpDeviceTimeoutSource *) g_source_new (&timeout_funcs,
                                                   sizeof (FpDeviceTimeoutSource));
  source->device = device;

  g_source_attach (&source->source, NULL);
  g_source_set_callback (&source->source, (GSourceFunc) func, user_data, destroy_notify);
  g_source_set_ready_time (&source->source,
                           g_source_get_time (&source->source) + interval * (guint64) 1000);
  priv->sources = g_slist_prepend (priv->sources, source);
  g_source_unref (&source->source);

  return &source->source;
}

/**
 * fpi_device_get_usb_device:
 * @device: The #FpDevice
 *
 * Get the #GUsbDevice for this #FpDevice. Only permissible to call if the
 * #FpDevice is of type %FP_DEVICE_TYPE_USB.
 *
 * Returns: The #GUsbDevice
 */
GUsbDevice *
fpi_device_get_usb_device (FpDevice *device)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);

  g_return_val_if_fail (FP_IS_DEVICE (device), NULL);
  g_return_val_if_fail (priv->type == FP_DEVICE_TYPE_USB, NULL);

  return priv->usb_device;
}

/**
 * fpi_device_get_virtual_env:
 * @device: The #FpDevice
 *
 * Get the value of the environment variable that caused the virtual #FpDevice to be
 * generated. Only permissible to call if the #FpDevice is of type %FP_DEVICE_TYPE_VIRTUAL.
 *
 * Returns: The value of the environment variable
 */
const gchar *
fpi_device_get_virtual_env (FpDevice *device)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);

  g_return_val_if_fail (FP_IS_DEVICE (device), NULL);
  g_return_val_if_fail (priv->type == FP_DEVICE_TYPE_VIRTUAL, NULL);

  return priv->virtual_env;
}

/**
 * fpi_device_get_current_action:
 * @device: The #FpDevice
 *
 * Get the currently ongoing action or %FPI_DEVICE_ACTION_NONE if there
 * is no operation at this time.
 *
 * This is useful for drivers that might share code paths between different
 * actions (e.g. verify and identify) and want to find out again later which
 * action was started in the beginning.
 *
 * Returns: The ongoing #FpiDeviceAction
 */
FpiDeviceAction
fpi_device_get_current_action (FpDevice *device)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);

  g_return_val_if_fail (FP_IS_DEVICE (device), FPI_DEVICE_ACTION_NONE);

  return priv->current_action;
}

/**
 * fpi_device_action_is_cancelled:
 * @device: The #FpDevice
 *
 * Checks whether the current action has been cancelled by the user.
 * This is equivalent to first getting the cancellable using
 * fpi_device_get_cancellable() and then checking whether it has been
 * cancelled (if it is non-NULL).
 *
 * Returns: %TRUE if action should be cancelled
 */
gboolean
fpi_device_action_is_cancelled (FpDevice *device)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);
  GCancellable *cancellable;

  g_return_val_if_fail (FP_IS_DEVICE (device), TRUE);
  g_return_val_if_fail (priv->current_action != FPI_DEVICE_ACTION_NONE, TRUE);

  cancellable = g_task_get_cancellable (priv->current_task);

  return g_cancellable_is_cancelled (cancellable);
}

/**
 * fpi_device_get_driver_data:
 * @device: The #FpDevice
 *
 * Returns: The driver data from the #FpIdEntry table entry
 */
guint64
fpi_device_get_driver_data (FpDevice *device)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);

  g_return_val_if_fail (FP_IS_DEVICE (device), 0);

  return priv->driver_data;
}

void
enroll_data_free (FpEnrollData *data)
{
  if (data->enroll_progress_destroy)
    data->enroll_progress_destroy (data->enroll_progress_data);
  data->enroll_progress_data = NULL;
  g_clear_object (&data->print);
  g_free (data);
}

void
match_data_free (FpMatchData *data)
{
  g_clear_object (&data->print);
  g_clear_object (&data->match);
  g_clear_error (&data->error);

  if (data->match_destroy)
    data->match_destroy (data->match_data);
  data->match_data = NULL;

  g_clear_object (&data->enrolled_print);
  g_clear_pointer (&data->gallery, g_ptr_array_unref);

  g_free (data);
}

/**
 * fpi_device_get_enroll_data:
 * @device: The #FpDevice
 * @print: (out) (transfer none): The user provided template print
 *
 * Get data for enrollment.
 */
void
fpi_device_get_enroll_data (FpDevice *device,
                            FpPrint **print)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);
  FpEnrollData *data;

  g_return_if_fail (FP_IS_DEVICE (device));
  g_return_if_fail (priv->current_action == FPI_DEVICE_ACTION_ENROLL);

  data = g_task_get_task_data (priv->current_task);
  g_assert (data);

  if (print)
    *print = data->print;
}

/**
 * fpi_device_get_capture_data:
 * @device: The #FpDevice
 * @wait_for_finger: (out): Whether to wait for finger or not
 *
 * Get data for capture.
 */
void
fpi_device_get_capture_data (FpDevice *device,
                             gboolean *wait_for_finger)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);

  g_return_if_fail (FP_IS_DEVICE (device));
  g_return_if_fail (priv->current_action == FPI_DEVICE_ACTION_CAPTURE);

  if (wait_for_finger)
    *wait_for_finger = priv->wait_for_finger;
}

/**
 * fpi_device_get_verify_data:
 * @device: The #FpDevice
 * @print: (out) (transfer none): The enrolled print
 *
 * Get data for verify.
 */
void
fpi_device_get_verify_data (FpDevice *device,
                            FpPrint **print)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);
  FpMatchData *data;

  g_return_if_fail (FP_IS_DEVICE (device));
  g_return_if_fail (priv->current_action == FPI_DEVICE_ACTION_VERIFY);

  data = g_task_get_task_data (priv->current_task);
  g_assert (data);

  if (print)
    *print = data->enrolled_print;
}

/**
 * fpi_device_get_identify_data:
 * @device: The #FpDevice
 * @prints: (out) (transfer none) (element-type FpPrint): The gallery of prints
 *
 * Get data for identify.
 */
void
fpi_device_get_identify_data (FpDevice   *device,
                              GPtrArray **prints)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);
  FpMatchData *data;

  g_return_if_fail (FP_IS_DEVICE (device));
  g_return_if_fail (priv->current_action == FPI_DEVICE_ACTION_IDENTIFY);

  data = g_task_get_task_data (priv->current_task);
  g_assert (data);

  if (prints)
    *prints = data->gallery;
}

/**
 * fpi_device_get_delete_data:
 * @device: The #FpDevice
 * @print: (out) (transfer none): The print to delete
 *
 * Get data for delete.
 */
void
fpi_device_get_delete_data (FpDevice *device,
                            FpPrint **print)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);

  g_return_if_fail (FP_IS_DEVICE (device));
  g_return_if_fail (priv->current_action == FPI_DEVICE_ACTION_DELETE);

  if (print)
    *print = g_task_get_task_data (priv->current_task);
}

/**
 * fpi_device_get_cancellable:
 * @device: The #FpDevice
 *
 * Retrieve the #GCancellable that may cancel the currently ongoing operation. This
 * is primarily useful to pass directly to e.g. fpi_usb_transfer_submit() for cancellable
 * transfers.
 * In many cases the cancel vfunc may be more convenient to react to cancellation in some
 * way.
 *
 * Returns: (transfer none): The #GCancellable for the current action.
 */
GCancellable *
fpi_device_get_cancellable (FpDevice *device)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);

  g_return_val_if_fail (FP_IS_DEVICE (device), NULL);
  g_return_val_if_fail (priv->current_action != FPI_DEVICE_ACTION_NONE, NULL);

  return g_task_get_cancellable (priv->current_task);
}

/**
 * fpi_device_action_error:
 * @device: The #FpDevice
 * @error: The #GError to return
 *
 * Finish an ongoing action with an error. This is the same as calling
 * the corresponding complete function such as fpi_device_open_complete()
 * with an error set. If possible, use the correct complete function as
 * that results in improved error detection.
 */
void
fpi_device_action_error (FpDevice *device,
                         GError   *error)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);

  g_return_if_fail (FP_IS_DEVICE (device));
  g_return_if_fail (priv->current_action != FPI_DEVICE_ACTION_NONE);

  if (error != NULL)
    {
      g_autofree char *action_str = NULL;

      action_str = g_enum_to_string (FPI_TYPE_DEVICE_ACTION, priv->current_action);
      g_debug ("Device reported generic error (%s) during action; action was: %s",
               error->message, action_str);
    }
  else
    {
      g_warning ("Device failed to pass an error to generic action error function");
      error = fpi_device_error_new_msg (FP_DEVICE_ERROR_GENERAL, "Device reported error but did not provide an error condition");
    }


  switch (priv->current_action)
    {
    case FPI_DEVICE_ACTION_PROBE:
      fpi_device_probe_complete (device, NULL, NULL, error);
      break;

    case FPI_DEVICE_ACTION_OPEN:
      fpi_device_open_complete (device, error);
      break;

    case FPI_DEVICE_ACTION_CLOSE:
      fpi_device_close_complete (device, error);
      break;

    case FPI_DEVICE_ACTION_ENROLL:
      fpi_device_enroll_complete (device, NULL, error);
      break;

    case FPI_DEVICE_ACTION_VERIFY:
      fpi_device_verify_complete (device, error);
      break;

    case FPI_DEVICE_ACTION_IDENTIFY:
      fpi_device_identify_complete (device, error);
      break;

    case FPI_DEVICE_ACTION_CAPTURE:
      fpi_device_capture_complete (device, NULL, error);
      break;

    case FPI_DEVICE_ACTION_DELETE:
      fpi_device_delete_complete (device, error);
      break;

    case FPI_DEVICE_ACTION_LIST:
      fpi_device_list_complete (device, NULL, error);
      break;

    default:
    case FPI_DEVICE_ACTION_NONE:
      g_return_if_reached ();
      break;
    }
}

static void
clear_device_cancel_action (FpDevice *device)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);

  g_clear_pointer (&priv->current_idle_cancel_source, g_source_destroy);

  if (priv->current_cancellable_id)
    {
      g_cancellable_disconnect (g_task_get_cancellable (priv->current_task),
                                priv->current_cancellable_id);
      priv->current_cancellable_id = 0;
    }
}

typedef enum _FpDeviceTaskReturnType {
  FP_DEVICE_TASK_RETURN_INT,
  FP_DEVICE_TASK_RETURN_BOOL,
  FP_DEVICE_TASK_RETURN_OBJECT,
  FP_DEVICE_TASK_RETURN_PTR_ARRAY,
  FP_DEVICE_TASK_RETURN_ERROR,
} FpDeviceTaskReturnType;

typedef struct _FpDeviceTaskReturnData
{
  FpDevice              *device;
  FpDeviceTaskReturnType type;
  gpointer               result;
} FpDeviceTaskReturnData;

static gboolean
fp_device_task_return_in_idle_cb (gpointer user_data)
{
  FpDeviceTaskReturnData *data = user_data;
  FpDevicePrivate *priv = fp_device_get_instance_private (data->device);
  g_autofree char *action_str = NULL;

  g_autoptr(GTask) task = NULL;


  action_str = g_enum_to_string (FPI_TYPE_DEVICE_ACTION, priv->current_action);
  g_debug ("Completing action %s in idle!", action_str);

  task = g_steal_pointer (&priv->current_task);
  priv->current_action = FPI_DEVICE_ACTION_NONE;
  priv->current_task_idle_return_source = NULL;

  switch (data->type)
    {
    case FP_DEVICE_TASK_RETURN_INT:
      g_task_return_int (task, GPOINTER_TO_INT (data->result));
      break;

    case FP_DEVICE_TASK_RETURN_BOOL:
      g_task_return_boolean (task, GPOINTER_TO_UINT (data->result));
      break;

    case FP_DEVICE_TASK_RETURN_OBJECT:
      g_task_return_pointer (task, data->result, g_object_unref);
      break;

    case FP_DEVICE_TASK_RETURN_PTR_ARRAY:
      g_task_return_pointer (task, data->result,
                             (GDestroyNotify) g_ptr_array_unref);
      break;

    case FP_DEVICE_TASK_RETURN_ERROR:
      g_task_return_error (task, data->result);
      break;

    default:
      g_assert_not_reached ();
    }

  return G_SOURCE_REMOVE;
}

static void
fpi_device_task_return_data_free (FpDeviceTaskReturnData *data)
{
  g_object_unref (data->device);
  g_free (data);
}

static void
fpi_device_return_task_in_idle (FpDevice              *device,
                                FpDeviceTaskReturnType return_type,
                                gpointer               return_data)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);
  FpDeviceTaskReturnData *data;

  data = g_new0 (FpDeviceTaskReturnData, 1);
  data->device = g_object_ref (device);
  data->type = return_type;
  data->result = return_data;

  priv->current_task_idle_return_source = g_idle_source_new ();
  g_source_set_priority (priv->current_task_idle_return_source,
                         g_task_get_priority (priv->current_task));
  g_source_set_callback (priv->current_task_idle_return_source,
                         fp_device_task_return_in_idle_cb,
                         data,
                         (GDestroyNotify) fpi_device_task_return_data_free);

  g_source_attach (priv->current_task_idle_return_source, NULL);
  g_source_unref (priv->current_task_idle_return_source);
}

/**
 * fpi_device_probe_complete:
 * @device: The #FpDevice
 * @device_id: Unique ID for the device or %NULL
 * @device_name: Human readable name or %NULL for driver name
 * @error: The #GError or %NULL on success
 *
 * Finish an ongoing probe operation. If error is %NULL success is assumed.
 */
void
fpi_device_probe_complete (FpDevice    *device,
                           const gchar *device_id,
                           const gchar *device_name,
                           GError      *error)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);

  g_return_if_fail (FP_IS_DEVICE (device));
  g_return_if_fail (priv->current_action == FPI_DEVICE_ACTION_PROBE);

  g_debug ("Device reported probe completion");

  clear_device_cancel_action (device);

  if (!error)
    {
      if (device_id)
        {
          g_clear_pointer (&priv->device_id, g_free);
          priv->device_id = g_strdup (device_id);
          g_object_notify (G_OBJECT (device), "device-id");
        }
      if (device_name)
        {
          g_clear_pointer (&priv->device_name, g_free);
          priv->device_name = g_strdup (device_name);
          g_object_notify (G_OBJECT (device), "name");
        }
      fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_BOOL,
                                      GUINT_TO_POINTER (TRUE));
    }
  else
    {
      fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_ERROR, error);
    }
}

/**
 * fpi_device_open_complete:
 * @device: The #FpDevice
 * @error: The #GError or %NULL on success
 *
 * Finish an ongoing open operation. If error is %NULL success is assumed.
 */
void
fpi_device_open_complete (FpDevice *device, GError *error)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);

  g_return_if_fail (FP_IS_DEVICE (device));
  g_return_if_fail (priv->current_action == FPI_DEVICE_ACTION_OPEN);

  g_debug ("Device reported open completion");

  clear_device_cancel_action (device);

  if (!error)
    {
      priv->is_open = TRUE;
      g_object_notify (G_OBJECT (device), "open");
    }

  if (!error)
    fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_BOOL,
                                    GUINT_TO_POINTER (TRUE));
  else
    fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_ERROR, error);
}

/**
 * fpi_device_close_complete:
 * @device: The #FpDevice
 * @error: The #GError or %NULL on success
 *
 * Finish an ongoing close operation. If error is %NULL success is assumed.
 */
void
fpi_device_close_complete (FpDevice *device, GError *error)
{
  GError *nested_error = NULL;
  FpDevicePrivate *priv = fp_device_get_instance_private (device);

  g_return_if_fail (FP_IS_DEVICE (device));
  g_return_if_fail (priv->current_action == FPI_DEVICE_ACTION_CLOSE);

  g_debug ("Device reported close completion");

  clear_device_cancel_action (device);

  switch (priv->type)
    {
    case FP_DEVICE_TYPE_USB:
      if (!g_usb_device_close (priv->usb_device, &nested_error))
        {
          if (error == NULL)
            error = nested_error;
          fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_ERROR, error);
          return;
        }
      break;

    case FP_DEVICE_TYPE_VIRTUAL:
      break;

    default:
      g_assert_not_reached ();
      fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_ERROR,
                                      fpi_device_error_new (FP_DEVICE_ERROR_GENERAL));
      return;
    }

  if (!error)
    {
      priv->is_open = FALSE;
      g_object_notify (G_OBJECT (device), "open");
      fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_BOOL,
                                      GUINT_TO_POINTER (TRUE));
    }
  else
    {
      fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_ERROR, error);
    }
}

/**
 * fpi_device_enroll_complete:
 * @device: The #FpDevice
 * @print: (nullable) (transfer full): The #FpPrint or %NULL on failure
 * @error: The #GError or %NULL on success
 *
 * Finish an ongoing enroll operation. The #FpPrint can be stored by the
 * caller for later verification.
 */
void
fpi_device_enroll_complete (FpDevice *device, FpPrint *print, GError *error)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);

  g_return_if_fail (FP_IS_DEVICE (device));
  g_return_if_fail (priv->current_action == FPI_DEVICE_ACTION_ENROLL);

  g_debug ("Device reported enroll completion");

  clear_device_cancel_action (device);

  if (!error)
    {
      if (FP_IS_PRINT (print))
        {
          FpiPrintType print_type;

          g_object_get (print, "fpi-type", &print_type, NULL);
          if (print_type == FPI_PRINT_UNDEFINED)
            {
              g_warning ("Driver did not set the type on the returned print!");
              g_clear_object (&print);

              error = fpi_device_error_new_msg (FP_DEVICE_ERROR_GENERAL,
                                                "Driver provided incorrect print data!");
              fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_ERROR, error);
              return;
            }

          fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_OBJECT, print);
        }
      else
        {
          g_warning ("Driver did not provide a valid print and failed to provide an error!");
          error = fpi_device_error_new_msg (FP_DEVICE_ERROR_GENERAL,
                                            "Driver failed to provide print data!");
          fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_ERROR, error);
        }
    }
  else
    {
      fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_ERROR, error);
      if (FP_IS_PRINT (print))
        {
          g_warning ("Driver passed an error but also provided a print, returning error!");
          g_object_unref (print);
        }
    }
}

/**
 * fpi_device_verify_complete:
 * @device: The #FpDevice
 * @error: A #GError if result is %FPI_MATCH_ERROR
 *
 * Finish an ongoing verify operation. The returned print should be
 * representing the new scan and not the one passed for verification.
 *
 * Note that @error should only be set for actual errors. In the case
 * of retry errors, report these using fpi_device_verify_report()
 * and then call this function without any error argument.
 */
void
fpi_device_verify_complete (FpDevice *device,
                            GError   *error)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);
  FpMatchData *data;

  g_return_if_fail (FP_IS_DEVICE (device));
  g_return_if_fail (priv->current_action == FPI_DEVICE_ACTION_VERIFY);

  g_debug ("Device reported verify completion");

  data = g_task_get_task_data (priv->current_task);

  clear_device_cancel_action (device);

  if (!error)
    {
      if (!data->result_reported)
        {
          g_warning ("Driver reported successful verify complete but did not report the result earlier. Reporting error instead");
          fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_ERROR,
                                          fpi_device_error_new (FP_DEVICE_ERROR_GENERAL));
        }
      else if (data->error)
        {
          fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_ERROR, g_steal_pointer (&data->error));
        }
      else
        {
          fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_INT,
                                          GINT_TO_POINTER (data->match != NULL ? FPI_MATCH_SUCCESS : FPI_MATCH_FAIL));
        }
    }
  else
    {
      /* Replace a retry error with a general error, this is a driver bug. */
      if (error->domain == FP_DEVICE_RETRY)
        {
          g_warning ("Driver reported a retry error to fpi_device_verify_complete. "
                     "This is not permissible and needs to be reported using "
                     "fpi_device_verify_report, reporting general verification "
                     "failure instead.");
          g_clear_error (&error);
          error = fpi_device_error_new (FP_DEVICE_ERROR_GENERAL);
        }
      fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_ERROR, error);
    }
}

/**
 * fpi_device_identify_complete:
 * @device: The #FpDevice
 * @error: The #GError or %NULL on success
 *
 * Finish an ongoing identify operation. The match that was identified is
 * returned in @match. The @print parameter returns the newly created scan
 * that was used for matching.
 */
void
fpi_device_identify_complete (FpDevice *device,
                              GError   *error)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);
  FpMatchData *data;

  g_return_if_fail (FP_IS_DEVICE (device));
  g_return_if_fail (priv->current_action == FPI_DEVICE_ACTION_IDENTIFY);

  g_debug ("Device reported identify completion");

  data = g_task_get_task_data (priv->current_task);

  clear_device_cancel_action (device);

  if (!error)
    {
      if (!data->result_reported)
        {
          g_warning ("Driver reported successful identify complete but did not report the result earlier. Reporting error instead");
          fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_ERROR,
                                          fpi_device_error_new (FP_DEVICE_ERROR_GENERAL));
        }
      else if (data->error)
        {
          fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_ERROR, g_steal_pointer (&data->error));
        }
      else
        {
          fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_INT, GINT_TO_POINTER (TRUE));
        }
    }
  else
    {
      /* Replace a retry error with a general error, this is a driver bug. */
      if (error->domain == FP_DEVICE_RETRY)
        {
          g_warning ("Driver reported a retry error to fpi_device_identify_complete. "
                     "This is not permissible and needs to be reported using "
                     "fpi_device_identify_report, reporting general identification "
                     "failure instead.");
          g_clear_error (&error);
          error = fpi_device_error_new (FP_DEVICE_ERROR_GENERAL);
        }
      fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_ERROR, error);
    }
}


/**
 * fpi_device_capture_complete:
 * @device: The #FpDevice
 * @image: The #FpImage, or %NULL on error
 * @error: The #GError or %NULL on success
 *
 * Finish an ongoing capture operation.
 */
void
fpi_device_capture_complete (FpDevice *device,
                             FpImage  *image,
                             GError   *error)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);

  g_return_if_fail (FP_IS_DEVICE (device));
  g_return_if_fail (priv->current_action == FPI_DEVICE_ACTION_CAPTURE);

  g_debug ("Device reported capture completion");

  clear_device_cancel_action (device);

  if (!error)
    {
      if (image)
        {
          fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_OBJECT, image);
        }
      else
        {
          g_warning ("Driver did not provide an error for a failed capture operation!");
          error = fpi_device_error_new_msg (FP_DEVICE_ERROR_GENERAL,
                                            "Driver failed to provide an error!");
          fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_ERROR, error);
        }
    }
  else
    {
      fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_ERROR, error);
      if (image)
        {
          g_warning ("Driver passed an error but also provided an image, returning error!");
          g_clear_object (&image);
        }
    }
}

/**
 * fpi_device_delete_complete:
 * @device: The #FpDevice
 * @error: The #GError or %NULL on success
 *
 * Finish an ongoing delete operation.
 */
void
fpi_device_delete_complete (FpDevice *device,
                            GError   *error)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);

  g_return_if_fail (FP_IS_DEVICE (device));
  g_return_if_fail (priv->current_action == FPI_DEVICE_ACTION_DELETE);

  g_debug ("Device reported deletion completion");

  clear_device_cancel_action (device);

  if (!error)
    fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_BOOL,
                                    GUINT_TO_POINTER (TRUE));
  else
    fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_ERROR, error);
}

/**
 * fpi_device_list_complete:
 * @device: The #FpDevice
 * @prints: (element-type FpPrint) (transfer container): Possibly empty array of prints or %NULL on error
 * @error: The #GError or %NULL on success
 *
 * Finish an ongoing list operation.
 *
 * Please note that the @prints array will be free'ed using
 * g_ptr_array_unref() and the elements are destroyed automatically.
 * As such, you must use g_ptr_array_new_with_free_func() with
 * g_object_unref() as free func to create the array.
 */
void
fpi_device_list_complete (FpDevice  *device,
                          GPtrArray *prints,
                          GError    *error)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);

  g_return_if_fail (FP_IS_DEVICE (device));
  g_return_if_fail (priv->current_action == FPI_DEVICE_ACTION_LIST);

  g_debug ("Device reported listing completion");

  clear_device_cancel_action (device);

  if (prints && error)
    {
      g_warning ("Driver reported back prints and error, ignoring prints");
      g_clear_pointer (&prints, g_ptr_array_unref);
    }
  else if (!prints && !error)
    {
      g_warning ("Driver did not pass array but failed to provide an error");
      error = fpi_device_error_new_msg (FP_DEVICE_ERROR_GENERAL,
                                        "Driver failed to provide a list of prints");
    }

  if (!error)
    fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_PTR_ARRAY, prints);
  else
    fpi_device_return_task_in_idle (device, FP_DEVICE_TASK_RETURN_ERROR, error);
}

/**
 * fpi_device_enroll_progress:
 * @device: The #FpDevice
 * @completed_stages: The number of stages that are completed at this point
 * @print: (transfer floating): The #FpPrint for the newly completed stage or %NULL on failure
 * @error: (transfer full): The #GError or %NULL on success
 *
 * Notify about the progress of the enroll operation. This is important for UI interaction.
 * The passed error may be used if a scan needs to be retried, use fpi_device_retry_new().
 */
void
fpi_device_enroll_progress (FpDevice *device,
                            gint      completed_stages,
                            FpPrint  *print,
                            GError   *error)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);
  FpEnrollData *data;

  g_return_if_fail (FP_IS_DEVICE (device));
  g_return_if_fail (priv->current_action == FPI_DEVICE_ACTION_ENROLL);
  g_return_if_fail (error == NULL || error->domain == FP_DEVICE_RETRY);

  g_debug ("Device reported enroll progress, reported %i of %i have been completed", completed_stages, priv->nr_enroll_stages);

  if (print)
    g_object_ref_sink (print);

  if (error && print)
    {
      g_warning ("Driver passed an error and also provided a print, returning error!");
      g_clear_object (&print);
    }

  data = g_task_get_task_data (priv->current_task);

  if (data->enroll_progress_cb)
    {
      data->enroll_progress_cb (device,
                                completed_stages,
                                print,
                                data->enroll_progress_data,
                                error);
    }

  g_clear_error (&error);
  g_clear_object (&print);
}

/**
 * fpi_device_verify_report:
 * @device: The #FpDevice
 * @result: The #FpiMatchResult of the operation
 * @print: (transfer floating) The scanned #FpPrint
 * @error: A #GError if result is %FPI_MATCH_ERROR
 *
 * Report the result of a verify operation. Note that the passed @error must be
 * a retry error with the %FP_DEVICE_RETRY domain. For all other error cases,
 * the error should passed to fpi_device_verify_complete().
 */
void
fpi_device_verify_report (FpDevice      *device,
                          FpiMatchResult result,
                          FpPrint       *print,
                          GError        *error)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);
  FpMatchData *data = g_task_get_task_data (priv->current_task);
  gboolean call_cb = TRUE;

  g_return_if_fail (FP_IS_DEVICE (device));
  g_return_if_fail (priv->current_action == FPI_DEVICE_ACTION_VERIFY);
  g_return_if_fail (data->result_reported == FALSE);

  data->result_reported = TRUE;

  g_debug ("Device reported verify result");

  if (print)
    print = g_object_ref_sink (print);

  if (error || result == FPI_MATCH_ERROR)
    {
      if (result != FPI_MATCH_ERROR)
        g_warning ("Driver reported an error code without setting match result to error!");

      if (error == NULL)
        {
          g_warning ("Driver reported an error without specifying a retry code, assuming general retry error!");
          error = fpi_device_retry_new (FP_DEVICE_RETRY_GENERAL);
        }

      if (print)
        {
          g_warning ("Driver reported a print together with an error!");
          g_clear_object (&print);
        }

      data->error = error;

      if (error->domain != FP_DEVICE_RETRY)
        {
          g_warning ("Driver reported a verify error that was not in the retry domain, delaying report!");
          call_cb = FALSE;
        }
    }
  else
    {
      if (result == FPI_MATCH_SUCCESS)
        {
          fpi_device_get_verify_data (device, &data->match);
          g_object_ref (data->match);
        }

      data->print = g_steal_pointer (&print);
    }

  if (call_cb && data->match_cb)
    data->match_cb (device, data->match, data->print, data->match_data, data->error);
}

/**
 * fpi_device_identify_report:
 * @device: The #FpDevice
 * @match: (transfer none): The #FpPrint from the gallery that matched
 * @print: (transfer floating): The scanned #FpPrint
 * @error: A #GError if result is %FPI_MATCH_ERROR
 *
 * Report the result of a identify operation. Note that the passed @error must be
 * a retry error with the %FP_DEVICE_RETRY domain. For all other error cases,
 * the error should passed to fpi_device_identify_complete().
 */
void
fpi_device_identify_report (FpDevice *device,
                            FpPrint  *match,
                            FpPrint  *print,
                            GError   *error)
{
  FpDevicePrivate *priv = fp_device_get_instance_private (device);
  FpMatchData *data = g_task_get_task_data (priv->current_task);
  gboolean call_cb = TRUE;

  g_return_if_fail (FP_IS_DEVICE (device));
  g_return_if_fail (priv->current_action == FPI_DEVICE_ACTION_IDENTIFY);
  g_return_if_fail (data->result_reported == FALSE);

  data->result_reported = TRUE;

  if (match)
    g_object_ref (match);

  if (print)
    print = g_object_ref_sink (print);

  if (match && !g_ptr_array_find (data->gallery, match, NULL))
    {
      g_warning ("Driver reported a match to a print that was not in the gallery, ignoring match.");
      g_clear_object (&match);
    }

  g_debug ("Device reported identify result");

  if (error)
    {
      if (match != NULL)
        {
          g_warning ("Driver reported an error code but also provided a match!");
          g_clear_object (&match);
        }

      if (print)
        {
          g_warning ("Driver reported a print together with an error!");
          g_clear_object (&print);
        }

      data->error = error;

      if (error->domain != FP_DEVICE_RETRY)
        {
          g_warning ("Driver reported a verify error that was not in the retry domain, delaying report!");
          call_cb = FALSE;
        }
    }
  else
    {
      if (match)
        data->match = g_steal_pointer (&match);

      if (print)
        data->print = g_steal_pointer (&print);
    }

  if (call_cb && data->match_cb)
    data->match_cb (device, data->match, data->print, data->match_data, data->error);
}