Enrollment tweaks

upekts will need to know when the first enrollment stage is attempted for
the first time, so add an __enroll_stage counter which actually indicates
the next stage to enroll. -1 is a special value and it means 0 is next *and*
it is the initial attemt.

Added more debug output to the enroll handler.
Added new fp_enroll_status codes for too short or uncentered scans.

Changed the print_data allocator to consider the device rather than the
driver, this feels more natural. Added missing return value.

Make fp_enroll_status codes start at 1. 0 can now be used as a
special/temporary value by the drivers. Also check that we aren't exceeding
the number of enroll stages.

Also add a missing exit() call to the verify example and update for the
above.

examples/verify.c

@@ -60,6 +60,13 @@ struct fp_print_data *enroll(struct fp_dev *dev) {
 		case FP_ENROLL_RETRY:
 			printf("Didn't quite catch that. Please try again.\n");
 			break;
+		case FP_ENROLL_RETRY_TOO_SHORT:
+			printf("Your swipe was too short, please try again.\n");
+			break;
+		case FP_ENROLL_RETRY_CENTER_FINGER:
+			printf("Didn't catch that, please center your finger on the "
+				"sensor and try again.\n");
+			break;
 		}
 	} while (status != FP_ENROLL_COMPLETE);
 
@@ -103,6 +110,7 @@ int main(void)
 	fp_dscv_devs_free(discovered_devs);
 	if (!dev) {
 		fprintf(stderr, "Could not open device.\n");
+		exit(1);
 	}
 
 	printf("Opened device. It's now time to enroll your finger.\n\n");

libfprint/core.c

@@ -178,6 +178,7 @@ API_EXPORTED struct fp_dev *fp_dev_open(struct fp_dscv_dev *ddev)
 	dev = g_malloc0(sizeof(*dev));
 	dev->drv = drv;
 	dev->udev = udevh;
+	dev->__enroll_stage = -1;
 
 	if (drv->init) {
 		r = drv->init(dev);
@@ -226,13 +227,58 @@ API_EXPORTED enum fp_enroll_status fp_enroll_finger(struct fp_dev *dev,
 	struct fp_print_data **print_data)
 {
 	const struct fp_driver *drv = dev->drv;
+	enum fp_enroll_status ret;
+	int stage = dev->__enroll_stage;
+	gboolean initial = FALSE;
+
 	if (!dev->nr_enroll_stages || !drv->enroll) {
 		fp_err("driver %s has 0 enroll stages or no enroll func",
 			dev->drv->name);
 		return FP_ENROLL_FAIL;
 	}
 
-	return drv->enroll(dev, print_data);
+	if (stage == -1) {
+		initial = TRUE;
+		dev->__enroll_stage = ++stage;
+	}
+
+	if (stage >= dev->nr_enroll_stages) {
+		fp_err("exceeding number of enroll stages for device claimed by "
+			"driver %s (%d stages)", dev->drv->name, dev->nr_enroll_stages);
+		return FP_ENROLL_FAIL;
+	}
+	fp_dbg("%s will handle enroll stage %d/%d%s", drv->name, stage,
+		dev->nr_enroll_stages - 1, initial ? " (initial)" : "");
+
+	ret = drv->enroll(dev, initial, stage, print_data);
+	switch (ret) {
+	case FP_ENROLL_PASS:
+		fp_dbg("enroll stage passed");
+		dev->__enroll_stage = stage + 1;
+		break;
+	case FP_ENROLL_COMPLETE:
+		fp_dbg("enroll complete");
+		dev->__enroll_stage = -1;
+		break;
+	case FP_ENROLL_RETRY:
+		fp_dbg("enroll should retry");
+		break;
+	case FP_ENROLL_RETRY_TOO_SHORT:
+		fp_dbg("swipe was too short, enroll should retry");
+		break;
+	case FP_ENROLL_RETRY_CENTER_FINGER:
+		fp_dbg("finger was not centered, enroll should retry");
+		break;
+	case FP_ENROLL_FAIL:
+		fp_err("enroll failed");
+		dev->__enroll_stage = -1;
+		break;
+	default:
+		fp_err("unrecognised return code %d", ret);
+		dev->__enroll_stage = -1;
+		return FP_ENROLL_FAIL;
+	}
+	return ret;
 }
 
 API_EXPORTED int fp_init(void)

libfprint/data.c

@@ -24,12 +24,13 @@
 
 #include "fp_internal.h"
 
-struct fp_print_data *fpi_print_data_new(struct fp_driver *drv, size_t length)
+struct fp_print_data *fpi_print_data_new(struct fp_dev *dev, size_t length)
 {
 	struct fp_print_data *data = g_malloc(sizeof(*data) + length);
-	fp_dbg("length=%z", length);
-	data->driver_name = drv->name;
+	fp_dbg("length=%zd", length);
+	data->driver_name = dev->drv->name;
 	data->length = length;
+	return data;
 }
 
 unsigned char *fpi_print_data_get_buffer(struct fp_print_data *data)

libfprint/fp_internal.h

@@ -22,6 +22,7 @@
 
 #include <stdint.h>
 
+#include <glib.h>
 #include <usb.h>
 
 #ifdef __DARWIN_NULL
@@ -65,6 +66,9 @@ struct fp_dev {
 	void *priv;
 
 	int nr_enroll_stages;
+
+	/* drivers should not mess with these */
+	int __enroll_stage;
 };
 
 struct usb_id {
@@ -81,8 +85,8 @@ struct fp_driver {
 	/* Device operations */
 	int (*init)(struct fp_dev *dev);
 	void (*exit)(struct fp_dev *dev);
-	enum fp_enroll_status (*enroll)(struct fp_dev *dev,
-		struct fp_print_data **print_data);
+	enum fp_enroll_status (*enroll)(struct fp_dev *dev, gboolean initial,
+		int stage, struct fp_print_data **print_data);
 };
 
 extern const struct fp_driver upekts_driver;
@@ -98,7 +102,7 @@ struct fp_print_data {
 	unsigned char buffer[0];
 };
 
-struct fp_print_data *fpi_print_data_new(struct fp_driver *drv, size_t length);
+struct fp_print_data *fpi_print_data_new(struct fp_dev *dev, size_t length);
 unsigned char *fpi_print_data_get_buffer(struct fp_print_data *data);
 int fpi_print_data_compatible(struct fp_dev *dev, struct fp_print_data *data);
 

libfprint/fprint.h

@@ -43,10 +43,12 @@ const char *fp_driver_get_full_name(const struct fp_driver *drv);
 
 /* Enrolment */
 enum fp_enroll_status {
-	FP_ENROLL_COMPLETE,
+	FP_ENROLL_COMPLETE = 1,
 	FP_ENROLL_FAIL,
 	FP_ENROLL_PASS,
 	FP_ENROLL_RETRY,
+	FP_ENROLL_RETRY_TOO_SHORT,
+	FP_ENROLL_RETRY_CENTER_FINGER,
 };
 
 enum fp_enroll_status fp_enroll_finger(struct fp_dev *dev,