qapi: Add qobject_is_equal()

This generic function (along with its implementations for different
types) determines whether two QObjects are equal.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-id: 20171114180128.17076-4-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/qobject/qlist.c b/qobject/qlist.c
index 86b60cb..3ef57d3 100644
--- a/qobject/qlist.c
+++ b/qobject/qlist.c
@@ -140,6 +140,38 @@ QList *qobject_to_qlist(const QObject *obj)
 }
 
 /**
+ * qlist_is_equal(): Test whether the two QLists are equal
+ *
+ * In order to be considered equal, the respective two objects at each
+ * index of the two lists have to compare equal (regarding
+ * qobject_is_equal()), and both lists have to have the same number of
+ * elements.
+ * That means both lists have to contain equal objects in equal order.
+ */
+bool qlist_is_equal(const QObject *x, const QObject *y)
+{
+    const QList *list_x = qobject_to_qlist(x);
+    const QList *list_y = qobject_to_qlist(y);
+    const QListEntry *entry_x, *entry_y;
+
+    entry_x = qlist_first(list_x);
+    entry_y = qlist_first(list_y);
+
+    while (entry_x && entry_y) {
+        if (!qobject_is_equal(qlist_entry_obj(entry_x),
+                              qlist_entry_obj(entry_y)))
+        {
+            return false;
+        }
+
+        entry_x = qlist_next(entry_x);
+        entry_y = qlist_next(entry_y);
+    }
+
+    return !entry_x && !entry_y;
+}
+
+/**
  * qlist_destroy_obj(): Free all the memory allocated by a QList
  */
 void qlist_destroy_obj(QObject *obj)