From 704c19b87aea15abc03290f61f97f760f03da527 Mon Sep 17 00:00:00 2001
From: Bastien Nocera <hadess@hadess.net>
Date: Wed, 7 Aug 2019 15:27:37 +0200
Subject: [PATCH] device: Restart verification if error is "retry"

fprintd's API docs say that "retry" errors for verification
"the verification is still ongoing" and that "[the] user should retry
scanning their finger.

Unfortunately, retry errors are fatal in libfprint. Make fprintd restart
operations when "retry" is the error for either identification or
verification purposes.

We need to also make sure that a "*Stop" D-Bus call will return as
normal if called while we're stopping a verification or identification
in order to restart it.

Closes: #22
---
 src/device.c | 93 +++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 85 insertions(+), 8 deletions(-)

diff --git a/src/device.c b/src/device.c
index a305c9f..d4d9b53 100644
--- a/src/device.c
+++ b/src/device.c
@@ -749,8 +749,30 @@ static void fprint_device_release(FprintDevice *rdev,
 	}
 }
 
-static void verify_cb(struct fp_dev *dev, int r, struct fp_img *img,
-		      void *user_data)
+static void verify_cb(struct fp_dev *dev,
+		      int            r,
+		      struct fp_img *img,
+		      void          *user_data);
+
+static void
+verify_restart_cb(struct fp_dev *dev,
+		  void          *user_data)
+{
+	struct FprintDevice *rdev = user_data;
+	FprintDevicePrivate *priv = DEVICE_GET_PRIVATE(rdev);
+
+	if (priv->current_action != ACTION_VERIFY)
+		return;
+
+	g_debug("verify_restart_cb: restarting verification");
+	fp_async_verify_start(priv->dev, priv->verify_data, verify_cb, rdev);
+}
+
+static void
+verify_cb(struct fp_dev *dev,
+	  int            r,
+	  struct fp_img *img,
+	  void          *user_data)
 {
 	struct FprintDevice *rdev = user_data;
 	FprintDevicePrivate *priv = DEVICE_GET_PRIVATE(rdev);
@@ -761,8 +783,20 @@ static void verify_cb(struct fp_dev *dev, int r, struct fp_img *img,
 
 	g_debug("verify_cb: result %s (%d)", name, r);
 
-	if (r == FP_VERIFY_NO_MATCH || r == FP_VERIFY_MATCH || r < 0)
-		priv->action_done = TRUE;
+	if (r == FP_VERIFY_RETRY ||
+	    r == FP_VERIFY_RETRY_TOO_SHORT ||
+	    r == FP_VERIFY_RETRY_CENTER_FINGER ||
+	    r == FP_VERIFY_RETRY_REMOVE_FINGER) {
+		g_debug ("verify_cb: stopping current verification to retry");
+		fp_img_free(img);
+		if (fp_async_verify_stop(priv->dev, verify_restart_cb, user_data) == 0) {
+			g_signal_emit(rdev, signals[SIGNAL_VERIFY_STATUS], 0, name, priv->action_done);
+			return;
+		}
+		/* fallthrough to error out if restarting failed */
+	}
+
+	priv->action_done = TRUE;
 	set_disconnected (priv, name);
 	g_signal_emit(rdev, signals[SIGNAL_VERIFY_STATUS], 0, name, priv->action_done);
 	fp_img_free(img);
@@ -773,8 +807,32 @@ static void verify_cb(struct fp_dev *dev, int r, struct fp_img *img,
 	}
 }
 
-static void identify_cb(struct fp_dev *dev, int r,
-			 size_t match_offset, struct fp_img *img, void *user_data)
+static void identify_cb(struct fp_dev *dev,
+			int            r,
+			size_t         match_offset,
+			struct fp_img *img,
+			void          *user_data);
+
+static void
+identify_restart_cb(struct fp_dev *dev,
+		    void          *user_data)
+{
+	struct FprintDevice *rdev = user_data;
+	FprintDevicePrivate *priv = DEVICE_GET_PRIVATE(rdev);
+
+	if (priv->current_action != ACTION_IDENTIFY)
+		return;
+
+	g_debug("identify_restart_cb: restarting identification");
+	fp_async_identify_start (priv->dev, priv->identify_data, identify_cb, rdev);
+}
+
+static void
+identify_cb(struct fp_dev *dev,
+	    int            r,
+	    size_t         match_offset,
+	    struct fp_img *img,
+	    void          *user_data)
 {
 	struct FprintDevice *rdev = user_data;
 	FprintDevicePrivate *priv = DEVICE_GET_PRIVATE(rdev);
@@ -785,8 +843,20 @@ static void identify_cb(struct fp_dev *dev, int r,
 
 	g_debug("identify_cb: result %s (%d)", name, r);
 
-	if (r == FP_VERIFY_NO_MATCH || r == FP_VERIFY_MATCH || r < 0)
-		priv->action_done = TRUE;
+	if (r == FP_VERIFY_RETRY ||
+	    r == FP_VERIFY_RETRY_TOO_SHORT ||
+	    r == FP_VERIFY_RETRY_CENTER_FINGER ||
+	    r == FP_VERIFY_RETRY_REMOVE_FINGER) {
+		g_debug ("identify_cb: stopping current identification to retry");
+		fp_img_free(img);
+		if (fp_async_identify_stop(priv->dev, identify_restart_cb, user_data) == 0) {
+			g_signal_emit(rdev, signals[SIGNAL_VERIFY_STATUS], 0, name, priv->action_done);
+			return;
+		}
+		/* fallthrough to error out if restarting failed */
+	}
+
+	priv->action_done = TRUE;
 	set_disconnected (priv, name);
 	g_signal_emit(rdev, signals[SIGNAL_VERIFY_STATUS], 0, name, priv->action_done);
 	fp_img_free(img);
@@ -990,6 +1060,13 @@ static void fprint_device_verify_stop(FprintDevice *rdev,
 		return;
 	}
 
+	if (r == -EINPROGRESS) {
+		g_debug ("%s stop already in progress",
+			 priv->current_action == ACTION_VERIFY ? "verification" : "identification");
+		dbus_g_method_return(context);
+		r = 0;
+	}
+
 	if (r < 0) {
 		g_set_error(&error, FPRINT_ERROR, FPRINT_ERROR_INTERNAL,
 			"Verify stop failed with error %d", r);