Implement qdict_flatten()

qdict_flatten(): For each nested QDict with key x, all fields with key y
are moved to this QDict and their key is renamed to "x.y". This operation
is applied recursively for nested QDicts.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

include/qapi/qmp/qdict.h

@@ -65,5 +65,6 @@ int qdict_get_try_bool(const QDict *qdict, const char *key, int def_value);
 const char *qdict_get_try_str(const QDict *qdict, const char *key);
 
 QDict *qdict_clone_shallow(const QDict *src);
+void qdict_flatten(QDict *qdict);
 
 #endif /* QDICT_H */

qobject/qdict.c

@@ -476,3 +476,54 @@ static void qdict_destroy_obj(QObject *obj)
 
     g_free(qdict);
 }
+
+static void qdict_do_flatten(QDict *qdict, QDict *target, const char *prefix)
+{
+    QObject *value;
+    const QDictEntry *entry, *next;
+    const char *new_key;
+    bool delete;
+
+    entry = qdict_first(qdict);
+
+    while (entry != NULL) {
+
+        next = qdict_next(qdict, entry);
+        value = qdict_entry_value(entry);
+        new_key = NULL;
+        delete = false;
+
+        if (prefix) {
+            qobject_incref(value);
+            new_key = g_strdup_printf("%s.%s", prefix, entry->key);
+            qdict_put_obj(target, new_key, value);
+            delete = true;
+        }
+
+        if (qobject_type(value) == QTYPE_QDICT) {
+            qdict_do_flatten(qobject_to_qdict(value), target,
+                             new_key ? new_key : entry->key);
+            delete = true;
+        }
+
+        if (delete) {
+            qdict_del(qdict, entry->key);
+
+            /* Restart loop after modifying the iterated QDict */
+            entry = qdict_first(qdict);
+            continue;
+        }
+
+        entry = next;
+    }
+}
+
+/**
+ * qdict_flatten(): For each nested QDict with key x, all fields with key y
+ * are moved to this QDict and their key is renamed to "x.y". This operation
+ * is applied recursively for nested QDicts.
+ */
+void qdict_flatten(QDict *qdict)
+{
+    qdict_do_flatten(qdict, qdict, NULL);
+}