Add a hash function specifically designed for unique-ids

3 files changed, 112 insertions, 1 deletions

diff --git a/libappstream-glib/as-self-test.c b/libappstream-glib/as-self-test.c
index ea5b2af..c80ed1d 100644
--- a/libappstream-glib/as-self-test.c
+++ b/libappstream-glib/as-self-test.c
@@ -4866,6 +4866,73 @@ as_test_store_merge_func (void)
 	g_assert_cmpstr (as_app_get_source_file (app2), ==, NULL);
 }
 
+/* shows the unique-id globbing functions at work */
+static void
+as_test_utils_unique_id_hash_func (void)
+{
+	AsApp *found;
+	g_autoptr(AsApp) app = NULL;
+	g_autoptr(GHashTable) hash = NULL;
+
+	/* create new app */
+	app = as_app_new ();
+	as_app_set_id (app, "org.gnome.Software.desktop");
+	as_app_set_branch (app, "master");
+	g_assert_cmpstr (as_app_get_unique_id (app), ==,
+			 "*/*/*/*/org.gnome.Software.desktop/master");
+
+	/* add to hash table using the unique ID as a key */
+	hash = g_hash_table_new ((GHashFunc) as_utils_unique_id_hash,
+				 (GEqualFunc) as_utils_unique_id_equal);
+	g_hash_table_insert (hash, (gpointer) as_app_get_unique_id (app), app);
+
+	/* get with exact key */
+	found = g_hash_table_lookup (hash, "*/*/*/*/org.gnome.Software.desktop/master");
+	g_assert (found != NULL);
+
+	/* get with more details specified */
+	found = g_hash_table_lookup (hash, "system/*/*/*/org.gnome.Software.desktop/master");
+	g_assert (found != NULL);
+
+	/* get with less details specified */
+	found = g_hash_table_lookup (hash, "*/*/*/*/org.gnome.Software.desktop/*");
+	g_assert (found != NULL);
+
+	/* different key */
+	found = g_hash_table_lookup (hash, "*/*/*/*/gimp.desktop/*");
+	g_assert (found == NULL);
+
+	/* different branch */
+	found = g_hash_table_lookup (hash, "*/*/*/*/org.gnome.Software.desktop/stable");
+	g_assert (found == NULL);
+}
+
+/* shows the as_utils_unique_id_*_safe functions are safe with bare text */
+static void
+as_test_utils_unique_id_hash_safe_func (void)
+{
+	AsApp *found;
+	g_autoptr(AsApp) app = NULL;
+	g_autoptr(GHashTable) hash = NULL;
+
+	/* create new app */
+	app = as_app_new ();
+	as_app_set_id (app, "org.gnome.Software.desktop");
+
+	/* add to hash table using the unique ID as a key */
+	hash = g_hash_table_new ((GHashFunc) as_utils_unique_id_hash,
+				 (GEqualFunc) as_utils_unique_id_equal);
+	g_hash_table_insert (hash, "dave", app);
+
+	/* get with exact key */
+	found = g_hash_table_lookup (hash, "dave");
+	g_assert (found != NULL);
+
+	/* different key */
+	found = g_hash_table_lookup (hash, "frank");
+	g_assert (found == NULL);
+}
+
 int
 main (int argc, char **argv)
 {
@@ -4875,6 +4942,8 @@ main (int argc, char **argv)
 	g_log_set_fatal_mask (NULL, G_LOG_LEVEL_ERROR | G_LOG_LEVEL_CRITICAL);
 
 	/* tests go here */
+	g_test_add_func ("/AppStream/utils{unique_id-hash}", as_test_utils_unique_id_hash_func);
+	g_test_add_func ("/AppStream/utils{unique_id-hash2}", as_test_utils_unique_id_hash_safe_func);
 	g_test_add_func ("/AppStream/utils{unique_id}", as_test_utils_unique_id_func);
 	g_test_add_func ("/AppStream/utils{locale-compat}", as_test_utils_locale_compat_func);
 	g_test_add_func ("/AppStream/utils{string-replace}", as_test_utils_string_replace_func);
diff --git a/libappstream-glib/as-utils.c b/libappstream-glib/as-utils.c
index c959677..6ec25cf 100644
--- a/libappstream-glib/as-utils.c
+++ b/libappstream-glib/as-utils.c
@@ -1828,7 +1828,7 @@ as_utils_unique_id_equal (const gchar *unique_id1, const gchar *unique_id2)
 	/* invalid */
 	if (!as_utils_unique_id_valid (unique_id1) ||
 	    !as_utils_unique_id_valid (unique_id2))
-		return FALSE;
+		return g_strcmp0 (unique_id1, unique_id2) == 0;
 
 	/* look at each part */
 	for (i = 0; i < AS_UTILS_UNIQUE_ID_PARTS; i++) {
@@ -1855,3 +1855,44 @@ as_utils_unique_id_equal (const gchar *unique_id1, const gchar *unique_id2)
 	}
 	return TRUE;
 }
+
+/**
+ * as_utils_unique_id_hash:
+ * @unique_id: a unique ID
+ *
+ * Converts a unique-id to a hash value.
+ *
+ * This function implements the widely used DJB hash on the ID subset of the
+ * unique-id string.
+ *
+ * It can be passed to g_hash_table_new() as the hash_func parameter,
+ * when using non-NULL strings or unique_ids as keys in a GHashTable.
+ *
+ * Returns: a hash value corresponding to the key
+ *
+ * Since: 0.6.2
+ */
+guint
+as_utils_unique_id_hash (const gchar *unique_id)
+{
+	gsize i;
+	guint hash = 5381;
+	guint section_cnt = 0;
+
+	/* not a unique ID */
+	if (!as_utils_unique_id_valid (unique_id))
+		return g_str_hash (unique_id);
+
+	/* only include the app-id */
+	for (i = 0; unique_id[i] != '\0'; i++) {
+		if (unique_id[i] == '/') {
+			if (++section_cnt > 4)
+				break;
+			continue;
+		}
+		if (section_cnt < 4)
+			continue;
+		hash = (guint) ((hash << 5) + hash) + (guint) (unique_id[i]);
+	}
+	return hash;
+}
diff --git a/libappstream-glib/as-utils.h b/libappstream-glib/as-utils.h
index e38c412..7f7cde1 100644
--- a/libappstream-glib/as-utils.h
+++ b/libappstream-glib/as-utils.h
@@ -141,6 +141,7 @@ gchar		*as_utils_unique_id_build	(AsAppScope	 scope,
 gboolean	 as_utils_unique_id_equal	(const gchar	*unique_id1,
 						 const gchar	*unique_id2);
 gboolean	 as_utils_unique_id_valid	(const gchar	*unique_id);
+guint		 as_utils_unique_id_hash	(const gchar	*unique_id);
 
 G_END_DECLS