device: add g_udev_device_get_current_tags

Starting with systemd-udevd 247 tags are "sticky" meaning that once
a tag is assigned to a device it will not be removed from the device
again until the device itself is removed.

New property CURRENT_TAGS has been added that works similar to the
existing TAGS property but only lists tags set by the most recent
uevent/database update.

https://lists.freedesktop.org/archives/systemd-devel/2020-November/045646.html

5 files changed, 47 insertions, 1 deletions

diff --git a/gudev/gudevdevice.c b/gudev/gudevdevice.c
index 248d272..25af9d1 100644
--- a/gudev/gudevdevice.c
+++ b/gudev/gudevdevice.c
@@ -76,6 +76,7 @@ struct _GUdevDevicePrivate
   gchar **property_keys;
   gchar **sysfs_attr_keys;
   gchar **tags;
+  gchar **current_tags;
   GHashTable *prop_strvs;
   GHashTable *sysfs_attr_strvs;
 };
@@ -91,6 +92,7 @@ g_udev_device_finalize (GObject *object)
   g_strfreev (device->priv->property_keys);
   g_strfreev (device->priv->sysfs_attr_keys);
   g_strfreev (device->priv->tags);
+  g_strfreev (device->priv->current_tags);
 
   if (device->priv->udevice != NULL)
     udev_device_unref (device->priv->udevice);
@@ -119,6 +121,20 @@ g_udev_device_init (GUdevDevice *device)
   device->priv = g_udev_device_get_instance_private (device);
 }
 
+static void
+fetch_current_tags (GUdevDevice *device)
+{
+  struct udev_list_entry *l;
+  GPtrArray *p;
+
+  p = g_ptr_array_new ();
+  for (l = udev_device_get_current_tags_list_entry (device->priv->udevice); l != NULL; l = udev_list_entry_get_next (l))
+    {
+      g_ptr_array_add (p, g_strdup (udev_list_entry_get_name (l)));
+    }
+  g_ptr_array_add (p, NULL);
+  device->priv->current_tags = (gchar **) g_ptr_array_free (p, FALSE);
+}
 
 GUdevDevice *
 _g_udev_device_new (struct udev_device *udevice)
@@ -128,6 +144,8 @@ _g_udev_device_new (struct udev_device *udevice)
   device =  G_UDEV_DEVICE (g_object_new (G_UDEV_TYPE_DEVICE, NULL));
   device->priv->udevice = udev_device_ref (udevice);
 
+  fetch_current_tags (device);
+
   return device;
 }
 
@@ -1207,6 +1225,26 @@ g_udev_device_get_tags (GUdevDevice  *device)
 }
 
 /**
+ * g_udev_device_get_current_tags:
+ * @device: A #GUdevDevice.
+ *
+ * Gets all current tags for @device.
+ *
+ * https://www.freedesktop.org/software/systemd/man/udev_device_has_current_tag.html
+ *
+ * Returns: (transfer none) (array zero-terminated=1) (element-type utf8): A %NULL terminated string array of current tags. This array is owned by @device and should not be freed by the caller.
+ *
+ * Since: 238
+ */
+const gchar* const *
+g_udev_device_get_current_tags (GUdevDevice *device)
+{
+  g_return_val_if_fail (G_UDEV_IS_DEVICE (device), NULL);
+
+  return (const gchar * const *) device->priv->current_tags;
+}
+
+/**
  * g_udev_device_get_is_initialized:
  * @device: A #GUdevDevice.
  *
diff --git a/gudev/gudevdevice.h b/gudev/gudevdevice.h
index 69ecc0a..7d674f9 100644
--- a/gudev/gudevdevice.h
+++ b/gudev/gudevdevice.h
@@ -115,6 +115,7 @@ gboolean            g_udev_device_get_sysfs_attr_as_boolean (GUdevDevice  *devic
 const gchar* const *g_udev_device_get_sysfs_attr_as_strv    (GUdevDevice  *device,
                                                              const gchar  *name);
 const gchar* const *g_udev_device_get_tags                  (GUdevDevice  *device);
+const gchar* const *g_udev_device_get_current_tags          (GUdevDevice  *device);
 
 gboolean            g_udev_device_has_sysfs_attr_uncached            (GUdevDevice  *device,
                                                                       const gchar  *key);
diff --git a/libgudev-1.0.sym b/libgudev-1.0.sym
index ab9cccf..170f202 100644
--- a/libgudev-1.0.sym
+++ b/libgudev-1.0.sym
@@ -44,6 +44,7 @@ global:
         g_udev_device_get_sysfs_attr_keys;
         g_udev_device_get_sysfs_path;
         g_udev_device_get_tags;
+        g_udev_device_get_current_tags;
         g_udev_device_get_type;
         g_udev_device_get_usec_since_initialized;
         g_udev_device_has_property;
diff --git a/meson.build b/meson.build
index f547a6d..3a1ec98 100644
--- a/meson.build
+++ b/meson.build
@@ -41,7 +41,7 @@ vapidir = join_paths(datadir, 'vala', 'vapi')
 cc = meson.get_compiler('c')
 
 glib_req = '>= 2.38.0'
-libudev_req = '>= 199'
+libudev_req = '>= 251'
 
 glib_dep = dependency('glib-2.0', version: glib_req)
 gobject_dep = dependency('gobject-2.0', version: glib_req)
diff --git a/tests/test-gudevdevice.c b/tests/test-gudevdevice.c
index a197c22..9639058 100644
--- a/tests/test-gudevdevice.c
+++ b/tests/test-gudevdevice.c
@@ -19,6 +19,7 @@ static void
 test_tags ()
 {
 	const char *expected_tags[] = { "tag1", "tag2", "tag3", NULL };
+	const char *expected_current_tags[] = { "tag2", "tag3", NULL };
 	struct udev *udev = NULL;
 	struct udev_device *udev_device = NULL;
 	g_autoptr(GUdevDevice) dev = NULL;
@@ -30,6 +31,7 @@ test_tags ()
 	g_setenv ("SEQNUM", "1", TRUE);
 	g_setenv ("TAGS", "tag1:tag2:tag3", TRUE);
 	g_setenv ("CURRENT_TAGS", "tag2:tag3", TRUE);
+	g_setenv ("UDEV_DATABASE_VERSION", "1", TRUE);
 
 	udev = udev_new ();
 	udev_device = udev_device_new_from_environment (udev);
@@ -38,8 +40,12 @@ test_tags ()
 
 	dev = _g_udev_device_new (udev_device);
 
+	g_assert_nonnull (g_udev_device_get_tags (dev));
 	g_assert_cmpstrv (expected_tags, g_udev_device_get_tags (dev));
 
+	g_assert_nonnull (g_udev_device_get_current_tags (dev));
+	g_assert_cmpstrv (expected_current_tags, g_udev_device_get_current_tags (dev));
+
 	g_clear_pointer (&udev, udev_unref);
 	g_clear_pointer (&udev_device, udev_device_unref);
 }