dev-vibra: Allow to check if the device is busy

We accept `NULL` to make the case of no haptic easy to handle.

Signed-off-by: Guido Günther <agx@sigxcpu.org>

src/fbd-dev-vibra.c

@@ -219,6 +219,7 @@ fbd_dev_vibra_class_init (FbdDevVibraClass *klass)
 static void
 fbd_dev_vibra_init (FbdDevVibra *self)
 {
+  self->id = -1;
 }
 
 FbdDevVibra *
@@ -330,11 +331,16 @@ fbd_dev_vibra_remove_effect (FbdDevVibra *self)
 {
   g_return_val_if_fail (FBD_IS_DEV_VIBRA (self), FALSE);
 
+  if (self->id == -1)
+    return TRUE;
+
   g_debug("Erasing vibra effect (%d)", self->fd);
   if (ioctl(self->fd, EVIOCRMFF, self->id) == -1) {
     g_warning  ("Failed to erase vibra effect with id %d: %s", self->id, strerror(errno));
+    self->id = -1;
     return FALSE;
   }
+  self->id = -1;
   return TRUE;
 }
 
@@ -346,6 +352,9 @@ fbd_dev_vibra_stop (FbdDevVibra *self)
 
   g_return_val_if_fail (FBD_IS_DEV_VIBRA (self), FALSE);
 
+  if (self->id == -1)
+    return TRUE;
+
   stop.type = EV_FF;
   stop.code = self->id;
   stop.value = 0;
@@ -365,3 +374,22 @@ fbd_dev_vibra_get_device (FbdDevVibra *self)
 
   return self->device;
 }
+
+/**
+ * fbd_dev_vibra_is_busy:
+ * @self: The vibra device
+ *
+ * Check whether the device is currently in used
+ *
+ * Returns: `TRUE` when the device is in use, otherwise `FALSE`
+ */
+gboolean
+fbd_dev_vibra_is_busy (FbdDevVibra *self)
+{
+  if (self == NULL)
+    return FALSE;
+
+  g_return_val_if_fail (FBD_IS_DEV_VIBRA (self), TRUE);
+
+  return self->id != -1;
+}

src/fbd-dev-vibra.h

@@ -21,6 +21,6 @@ gboolean     fbd_dev_vibra_periodic (FbdDevVibra *self, guint duration, guint ma
 gboolean     fbd_dev_vibra_stop (FbdDevVibra *self);
 gboolean     fbd_dev_vibra_remove_effect (FbdDevVibra *self);
 GUdevDevice *fbd_dev_vibra_get_device(FbdDevVibra *self);
-
+gboolean     fbd_dev_vibra_is_busy (FbdDevVibra *self);
 
 G_END_DECLS