Internal FpDevice

Internal FpDevice — Internal device routines

Functions

void (*FpTimeoutFunc) ()
GUsbDevice * fpi_device_get_usb_device ()
gpointer fpi_device_get_udev_data ()
const gchar * fpi_device_get_virtual_env ()
FpiDeviceAction fpi_device_get_current_action ()
GError * fpi_device_retry_new ()
GError * fpi_device_error_new ()
GError * fpi_device_retry_new_msg ()
GError * fpi_device_error_new_msg ()
guint64 fpi_device_get_driver_data ()
void fpi_device_get_enroll_data ()
void fpi_device_get_capture_data ()
void fpi_device_get_verify_data ()
void fpi_device_get_identify_data ()
void fpi_device_get_delete_data ()
GCancellable * fpi_device_get_cancellable ()
gboolean fpi_device_action_is_cancelled ()
GSource * fpi_device_add_timeout ()
void fpi_device_set_nr_enroll_stages ()
void fpi_device_set_scan_type ()
void fpi_device_update_features ()
void fpi_device_critical_enter ()
void fpi_device_critical_leave ()
void fpi_device_remove ()
gboolean fpi_device_report_finger_status ()
gboolean fpi_device_report_finger_status_changes ()
void fpi_device_action_error ()
void fpi_device_probe_complete ()
void fpi_device_open_complete ()
void fpi_device_close_complete ()
void fpi_device_enroll_complete ()
void fpi_device_verify_complete ()
void fpi_device_identify_complete ()
void fpi_device_capture_complete ()
void fpi_device_clear_storage_complete ()
void fpi_device_delete_complete ()
void fpi_device_list_complete ()
void fpi_device_suspend_complete ()
void fpi_device_resume_complete ()
void fpi_device_enroll_progress ()
void fpi_device_verify_report ()
void fpi_device_identify_report ()
void fpi_device_class_auto_initialize_features ()

Types and Values

Description

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.

Functions

FpTimeoutFunc ()

void
(*FpTimeoutFunc) (FpDevice *device,
                  gpointer user_data);

The prototype of the callback function for fpi_device_add_timeout().

Parameters

device

The FpDevice passed to fpi_device_add_timeout()

 

user_data

the data passed to fpi_device_add_timeout()

 

fpi_device_get_usb_device ()

GUsbDevice *
fpi_device_get_usb_device (FpDevice *device);

Get the GUsbDevice for this FpDevice. Only permissible to call if the FpDevice is of type FP_DEVICE_TYPE_USB.

Parameters

device

The FpDevice

 

Returns

The GUsbDevice


fpi_device_get_udev_data ()

gpointer
fpi_device_get_udev_data (FpDevice *device,
                          FpiDeviceUdevSubtypeFlags subtype);

Get a subtype-specific hardware resource for this FpDevice. Only permissible to call if the FpDevice is of type FP_DEVICE_TYPE_UDEV.

Parameters

device

The FpDevice

 

subtype

Which subtype to get information about

 

Returns

Depends on subtype ; for SPIDEV/HIDRAW returns a path to the relevant device.


fpi_device_get_virtual_env ()

const gchar *
fpi_device_get_virtual_env (FpDevice *device);

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.

Parameters

device

The FpDevice

 

Returns

The value of the environment variable


fpi_device_get_current_action ()

FpiDeviceAction
fpi_device_get_current_action (FpDevice *device);

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.

Parameters

device

The FpDevice

 

Returns

The ongoing FpiDeviceAction


fpi_device_retry_new ()

GError *
fpi_device_retry_new (FpDeviceRetry error);

Create a new retry error code for use with fpi_device_verify_complete() and similar calls.

Parameters

error

The FpDeviceRetry error value describing the issue

 

fpi_device_error_new ()

GError *
fpi_device_error_new (FpDeviceError error);

Create a new error code for use with fpi_device_verify_complete() and similar calls.

Parameters

error

The FpDeviceRetry error value describing the issue

 

fpi_device_retry_new_msg ()

GError *
fpi_device_retry_new_msg (FpDeviceRetry error,
                          const gchar *msg,
                          ...);

Create a new retry error code for use with fpi_device_verify_complete() and similar calls.

Parameters

error

The FpDeviceRetry error value describing the issue

 

msg

Custom message to use with printf-style formatting

 

...

args for msg

 

fpi_device_error_new_msg ()

GError *
fpi_device_error_new_msg (FpDeviceError error,
                          const gchar *msg,
                          ...);

Create a new error code for use with fpi_device_verify_complete() and similar calls.

Parameters

error

The FpDeviceRetry error value describing the issue

 

msg

Custom message to use with printf-style formatting

 

...

args for msg

 

fpi_device_get_driver_data ()

guint64
fpi_device_get_driver_data (FpDevice *device);

Parameters

device

The FpDevice

 

Returns

The driver data from the FpIdEntry table entry


fpi_device_get_enroll_data ()

void
fpi_device_get_enroll_data (FpDevice *device,
                            FpPrint **print);

Get data for enrollment.

Parameters

device

The FpDevice

 

print

The user provided template print.

[out][transfer none]

fpi_device_get_capture_data ()

void
fpi_device_get_capture_data (FpDevice *device,
                             gboolean *wait_for_finger);

Get data for capture.

Parameters

device

The FpDevice

 

wait_for_finger

Whether to wait for finger or not.

[out]

fpi_device_get_verify_data ()

void
fpi_device_get_verify_data (FpDevice *device,
                            FpPrint **print);

Get data for verify.

Parameters

device

The FpDevice

 

print

The enrolled print.

[out][transfer none]

fpi_device_get_identify_data ()

void
fpi_device_get_identify_data (FpDevice *device,
                              GPtrArray **prints);

Get data for identify.

Parameters

device

The FpDevice

 

prints

The gallery of prints.

[out][transfer none][element-type FpPrint]

fpi_device_get_delete_data ()

void
fpi_device_get_delete_data (FpDevice *device,
                            FpPrint **print);

Get data for delete.

Parameters

device

The FpDevice

 

print

The print to delete.

[out][transfer none]

fpi_device_get_cancellable ()

GCancellable *
fpi_device_get_cancellable (FpDevice *device);

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.

Parameters

device

The FpDevice

 

Returns

The GCancellable for the current action.

[transfer none]


fpi_device_action_is_cancelled ()

gboolean
fpi_device_action_is_cancelled (FpDevice *device);

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).

Parameters

device

The FpDevice

 

Returns

TRUE if action should be cancelled


fpi_device_add_timeout ()

GSource *
fpi_device_add_timeout (FpDevice *device,
                        gint interval,
                        FpTimeoutFunc func,
                        gpointer user_data,
                        GDestroyNotify destroy_notify);

Register a timeout to run. Drivers should always make sure that timers are cancelled when appropriate.

Parameters

device

The FpDevice

 

interval

The interval in milliseconds

 

func

The FpTimeoutFunc to call on timeout

 

user_data

User data to pass to the callback.

[nullable]

destroy_notify

GDestroyNotify for user_data .

[nullable]

Returns

A newly created and attached GSource.

[transfer none]


fpi_device_set_nr_enroll_stages ()

void
fpi_device_set_nr_enroll_stages (FpDevice *device,
                                 gint 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.

Parameters

device

The FpDevice

 

enroll_stages

The number of enroll stages

 

fpi_device_set_scan_type ()

void
fpi_device_set_scan_type (FpDevice *device,
                          FpScanType scan_type);

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.

Parameters

device

The FpDevice

 

scan_type

The scan type of the device

 

fpi_device_update_features ()

void
fpi_device_update_features (FpDevice *device,
                            FpDeviceFeature update,
                            FpDeviceFeature value);

Updates the feature flags for the device. This can be used to runtime detect features that are supported by the device.

Parameters

device

The FpDevice

 

update

The feature flags to update

 

value

The value to set the flags to

 

fpi_device_critical_enter ()

void
fpi_device_critical_enter (FpDevice *device);

Enter a critical section in the driver code where no outside calls from libfprint should happen. Drivers can already assume that everything happens from the same thread, however, that still allows e.g. the cancel vfunc to be called at any point in time.

Using this kind of critical section, the driver can assume that libfprint will not forward any external requests to the driver for the time being. This is for example useful to prevent cancellation while the device is being set up. Or, said differently, using this feature means that the cancel handler is able to make more assumptions about the current state.

Please note that the driver is not shielded from all external changes. For example the cancellable as returned by fpi_device_get_cancellable() will still change immediately.

The driver may call this function multiple times, but must also ensure that fpi_device_critical_leave() is called an equal amount of times and that all critical sections are left before command completion.

Parameters

device

The FpDevice

 

fpi_device_critical_leave ()

void
fpi_device_critical_leave (FpDevice *device);

Leave a critical section started by fpi_device_critical_enter().

Once all critical sections have been left, libfprint will start flushing out the queued up requests. This is done from the mainloop and the driver is protected from reentrency issues.

Parameters

device

The FpDevice

 

fpi_device_remove ()

void
fpi_device_remove (FpDevice *device);

Called to signal to the FpDevice that it has been unplugged (physically removed from the system).

For USB devices, this API is called automatically by FpContext.

Parameters

device

The FpDevice

 

fpi_device_report_finger_status ()

gboolean
fpi_device_report_finger_status (FpDevice *device,
                                 FpFingerStatusFlags finger_status);

Report the finger status for the device . This can be used by UI to give a feedback

Parameters

device

The FpDevice

 

finger_status

The current FpFingerStatusFlags to report

 

Returns

TRUE if changed


fpi_device_report_finger_status_changes ()

gboolean
fpi_device_report_finger_status_changes
                               (FpDevice *device,
                                FpFingerStatusFlags added_status,
                                FpFingerStatusFlags removed_status);

Report the finger status for the device adding the added_status flags and removing the removed_status flags.

This can be used by UI to give a feedback

Parameters

device

The FpDevice

 

added_status

The FpFingerStatusFlags to add

 

removed_status

The FpFingerStatusFlags to remove

 

Returns

TRUE if changed


fpi_device_action_error ()

void
fpi_device_action_error (FpDevice *device,
                         GError *error);

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.

Parameters

device

The FpDevice

 

error

The GError to return

 

fpi_device_probe_complete ()

void
fpi_device_probe_complete (FpDevice *device,
                           const gchar *device_id,
                           const gchar *device_name,
                           GError *error);

Finish an ongoing probe operation. If error is NULL success is assumed.

Parameters

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

 

fpi_device_open_complete ()

void
fpi_device_open_complete (FpDevice *device,
                          GError *error);

Finish an ongoing open operation. If error is NULL success is assumed.

Parameters

device

The FpDevice

 

error

The GError or NULL on success

 

fpi_device_close_complete ()

void
fpi_device_close_complete (FpDevice *device,
                           GError *error);

Finish an ongoing close operation. If error is NULL success is assumed.

Parameters

device

The FpDevice

 

error

The GError or NULL on success

 

fpi_device_enroll_complete ()

void
fpi_device_enroll_complete (FpDevice *device,
                            FpPrint *print,
                            GError *error);

Finish an ongoing enroll operation. The FpPrint can be stored by the caller for later verification.

Parameters

device

The FpDevice

 

print

The FpPrint or NULL on failure.

[nullable][transfer full]

error

The GError or NULL on success

 

fpi_device_verify_complete ()

void
fpi_device_verify_complete (FpDevice *device,
                            GError *error);

Finish an ongoing verify operation.

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.

If error is not set, we expect that a result (and print, in case) have been already reported via fpi_device_verify_report().

Parameters

device

The FpDevice

 

error

A GError if result is FPI_MATCH_ERROR

 

fpi_device_identify_complete ()

void
fpi_device_identify_complete (FpDevice *device,
                              GError *error);

Finish an ongoing identify operation.

Note that error should only be set for actual errors. In the case of retry errors, report these using fpi_device_identify_report() and then call this function without any error argument.

If error is not set, we expect that a match and / or a print have been already reported via fpi_device_identify_report()

Parameters

device

The FpDevice

 

error

The GError or NULL on success

 

fpi_device_capture_complete ()

void
fpi_device_capture_complete (FpDevice *device,
                             FpImage *image,
                             GError *error);

Finish an ongoing capture operation.

Parameters

device

The FpDevice

 

image

The FpImage, or NULL on error

 

error

The GError or NULL on success

 

fpi_device_clear_storage_complete ()

void
fpi_device_clear_storage_complete (FpDevice *device,
                                   GError *error);

Finish an ongoing clear_storage operation.

Parameters

device

The FpDevice

 

error

The GError or NULL on success

 

fpi_device_delete_complete ()

void
fpi_device_delete_complete (FpDevice *device,
                            GError *error);

Finish an ongoing delete operation.

Parameters

device

The FpDevice

 

error

The GError or NULL on success

 

fpi_device_list_complete ()

void
fpi_device_list_complete (FpDevice *device,
                          GPtrArray *prints,
                          GError *error);

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.

Parameters

device

The FpDevice

 

prints

Possibly empty array of prints or NULL on error.

[element-type FpPrint][transfer container]

error

The GError or NULL on success

 

fpi_device_suspend_complete ()

void
fpi_device_suspend_complete (FpDevice *device,
                             GError *error);

Finish a suspend request. Only return a NULL error if suspend has been correctly configured and the current action as returned by fpi_device_get_current_action() will continue to run after resume.

In all other cases an error must be returned. Should this happen, the current action will be cancelled before the error is forwarded to the application.

It is recommended to set error to FP_ERROR_NOT_IMPLEMENTED.

Parameters

device

The FpDevice

 

error

The GError or NULL on success

 

fpi_device_resume_complete ()

void
fpi_device_resume_complete (FpDevice *device,
                            GError *error);

Finish a resume request.

Parameters

device

The FpDevice

 

error

The GError or NULL on success

 

fpi_device_enroll_progress ()

void
fpi_device_enroll_progress (FpDevice *device,
                            gint completed_stages,
                            FpPrint *print,
                            GError *error);

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().

Parameters

device

The FpDevice

 

completed_stages

The number of stages that are completed at this point

 

print

The FpPrint for the newly completed stage or NULL on failure.

[transfer floating]

error

The GError or NULL on success.

[transfer full]

fpi_device_verify_report ()

void
fpi_device_verify_report (FpDevice *device,
                          FpiMatchResult result,
                          FpPrint *print,
                          GError *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().

Parameters

device

The FpDevice

 

result

The FpiMatchResult of the operation

 

print

(transfer floating) The scanned FpPrint

 

error

A GError if result is FPI_MATCH_ERROR

 

fpi_device_identify_report ()

void
fpi_device_identify_report (FpDevice *device,
                            FpPrint *match,
                            FpPrint *print,
                            GError *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().

Parameters

device

The FpDevice

 

match

The FpPrint from the gallery that matched.

[transfer none]

print

The scanned FpPrint.

[transfer floating]

error

A GError if result is FPI_MATCH_ERROR

 

fpi_device_class_auto_initialize_features ()

void
fpi_device_class_auto_initialize_features
                               (FpDeviceClass *device_class);

Initializes the FpDeviceClass features flags checking what device vfuncs are implemented. Drivers should call this at the end of the class initialization.

Types and Values

FpDeviceClass

typedef struct {
  /* Static information about the driver. */
  const gchar     *id;
  const gchar     *full_name;
  FpDeviceType     type;
  const FpIdEntry *id_table;
  FpDeviceFeature  features;

  /* Defaults for device properties */
  gint       nr_enroll_stages;
  FpScanType scan_type;

  /* Simple device temperature model constants */
  gint32 temp_hot_seconds;
  gint32 temp_cold_seconds;

  /* Callbacks */
  gint (*usb_discover) (GUsbDevice *usb_device);
  void (*probe)    (FpDevice *device);
  void (*open)     (FpDevice *device);
  void (*close)    (FpDevice *device);
  void (*enroll)   (FpDevice *device);
  void (*verify)   (FpDevice *device);
  void (*identify) (FpDevice *device);
  void (*capture)  (FpDevice *device);
  void (*list)     (FpDevice *device);
  void (*delete)   (FpDevice * device);
  void (*clear_storage)  (FpDevice * device);

  void (*cancel)   (FpDevice *device);
  void (*suspend)  (FpDevice *device);
  void (*resume)   (FpDevice *device);
} FpDeviceClass;

NOTE: If your driver is image based, then you should subclass FpImageDevice instead. FpImageDevice based drivers use a different way of interacting with libfprint.

These are the main entry points for drivers to implement. Drivers may not implement all of these entry points if they do not support the operation (or a default implementation is sufficient).

Drivers must eventually call the corresponding function to finish the operation. It is also acceptable to call the generic fpi_device_action_error() function but doing so is not recommended in most usecases.

Drivers must also handle cancellation properly for any long running operation (i.e. any operation that requires capturing). It is entirely fine to ignore cancellation requests for short operations (e.g. open/close).

Note that cancel , suspend and resume will not be called while the device is within a fpi_device_critical_enter()/fpi_device_critical_leave() block.

This API is solely intended for drivers. It is purely internal and neither API nor ABI stable.

Members

const gchar *id;

ID string for the driver. Should be a valid C identifier and should match the drivers file name.

 

const gchar *full_name;

Human readable description of the driver

 

FpDeviceType type;

The type of driver

 

const FpIdEntry *id_table;

The table of IDs to bind the driver to

 

FpDeviceFeature features;

The features the device supports, it can be initialized using fpi_device_class_auto_initialize_features() on class_init .

 

gint nr_enroll_stages;

The number of enroll stages supported devices need; use fpi_device_set_nr_enroll_stages() from probe if this is dynamic.

 

FpScanType scan_type;

The scan type of supported devices; use fpi_device_set_scan_type() from probe if this is dynamic.

 

gint32 temp_hot_seconds;

Assumed time in seconds for the device to become too hot after being mostly cold. Set to -1 if the device can be always-on.

 

gint32 temp_cold_seconds;

Assumed time in seconds for the device to be mostly cold after having been too hot to operate.

 

usb_discover ()

Class method to check whether a USB device is supported by the driver. Should return 0 if the device is unsupported and a positive score otherwise. The default score is 50 and the driver with the highest score will be loaded.

 

probe ()

Called immediately for all devices. Most drivers will not need to implement this. Drivers should setup the device identifier from the probe callback which will be used to verify the compatibility of stored FpPrint's. It is permissible to temporarily open the USB device if this is required for the operation. If an error is returned, then the device will be destroyed again immediately and never reported to the API user.

 

open ()

Open the device for further operations. Any of the normal actions are guaranteed to only happen when the device is open (this includes delete).

 

close ()

Close the device again

 

enroll ()

Start an enroll operation

 

verify ()

Start a verify operation

 

identify ()

Start an identify operation

 

capture ()

Start a capture operation

 

list ()

List prints stored on the device

 

delete ()

Delete a print from the device

 

clear_storage ()

Delete all prints from the device

 

cancel ()

Called on cancellation, this is a convenience to not need to handle the GCancellable directly by using fpi_device_get_cancellable().

 

suspend ()

Called when an interactive action is running (ENROLL, VERIFY, IDENTIFY or CAPTURE) and the system is about to go into suspend.

 

resume ()

Called to resume an ongoing interactive action after the system has resumed from suspend.

 

enum FpiDeviceAction

Current active action of the device. A driver can retrieve the action.

Members

FPI_DEVICE_ACTION_NONE

No action is active.

 

FPI_DEVICE_ACTION_PROBE

Probe device for support and information.

 

FPI_DEVICE_ACTION_OPEN

Device is currently being opened.

 

FPI_DEVICE_ACTION_CLOSE

Device is currently being closed.

 

FPI_DEVICE_ACTION_ENROLL

Device is currently enrolling.

 

FPI_DEVICE_ACTION_VERIFY

Device is currently verifying.

 

FPI_DEVICE_ACTION_IDENTIFY

Device is currently identifying.

 

FPI_DEVICE_ACTION_CAPTURE

Device is currently capturing an image.

 

FPI_DEVICE_ACTION_LIST

Device stored prints are being queried.

 

FPI_DEVICE_ACTION_DELETE

Device stored print is being deleted.

 

FPI_DEVICE_ACTION_CLEAR_STORAGE

Device stored prints are being deleted.

 

struct FpIdEntry

struct FpIdEntry {
  union
  {
    struct
    {
      guint pid;
      guint vid;
    };
    const gchar *virtual_envvar;
    struct
    {
      FpiDeviceUdevSubtypeFlags udev_types;
      const gchar              *spi_acpi_id;
      struct
      {
        guint pid;
        guint vid;
      } hid_id;
    };
  };
  guint64 driver_data;
};

An entry in the table of supported hardware. For USB devices, the product ID and vendor ID should be provided. The optional driver_data field defaults to 0 and can be used as a simple flag for device quirks.


enum FpiDeviceUdevSubtypeFlags

Bitfield of required hardware resources for a udev-backed device.

Members

FPI_DEVICE_UDEV_SUBTYPE_SPIDEV

The device requires an spidev node

 

FPI_DEVICE_UDEV_SUBTYPE_HIDRAW

The device requires a hidraw node