qom: DECLARE_*_CHECKERS macros

Sometimes the typedefs are buried inside another header, but
we want to benefit from the automatic definition of type cast
functions.  Introduce macros that will let type checkers be
defined when typedefs are already available.

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20200831210740.126168-5-ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

include/qom/object.h

@@ -553,6 +553,62 @@ struct Object
     Object *parent;
 };
 
+/**
+ * DECLARE_INSTANCE_CHECKER:
+ * @InstanceType: instance struct name
+ * @OBJ_NAME: the object name in uppercase with underscore separators
+ * @TYPENAME: type name
+ *
+ * Direct usage of this macro should be avoided, and the complete
+ * OBJECT_DECLARE_TYPE macro is recommended instead.
+ *
+ * This macro will provide the three standard type cast functions for a
+ * QOM type.
+ */
+#define DECLARE_INSTANCE_CHECKER(InstanceType, OBJ_NAME, TYPENAME) \
+    static inline G_GNUC_UNUSED InstanceType * \
+    OBJ_NAME(void *obj) \
+    { return OBJECT_CHECK(InstanceType, obj, TYPENAME); }
+
+/**
+ * DECLARE_CLASS_CHECKERS:
+ * @ClassType: class struct name
+ * @OBJ_NAME: the object name in uppercase with underscore separators
+ * @TYPENAME: type name
+ *
+ * Direct usage of this macro should be avoided, and the complete
+ * OBJECT_DECLARE_TYPE macro is recommended instead.
+ *
+ * This macro will provide the three standard type cast functions for a
+ * QOM type.
+ */
+#define DECLARE_CLASS_CHECKERS(ClassType, OBJ_NAME, TYPENAME) \
+    static inline G_GNUC_UNUSED ClassType * \
+    OBJ_NAME##_GET_CLASS(void *obj) \
+    { return OBJECT_GET_CLASS(ClassType, obj, TYPENAME); } \
+    \
+    static inline G_GNUC_UNUSED ClassType * \
+    OBJ_NAME##_CLASS(void *klass) \
+    { return OBJECT_CLASS_CHECK(ClassType, klass, TYPENAME); }
+
+/**
+ * DECLARE_OBJ_CHECKERS:
+ * @InstanceType: instance struct name
+ * @ClassType: class struct name
+ * @OBJ_NAME: the object name in uppercase with underscore separators
+ * @TYPENAME: type name
+ *
+ * Direct usage of this macro should be avoided, and the complete
+ * OBJECT_DECLARE_TYPE macro is recommended instead.
+ *
+ * This macro will provide the three standard type cast functions for a
+ * QOM type.
+ */
+#define DECLARE_OBJ_CHECKERS(InstanceType, ClassType, OBJ_NAME, TYPENAME) \
+    DECLARE_INSTANCE_CHECKER(InstanceType, OBJ_NAME, TYPENAME) \
+    \
+    DECLARE_CLASS_CHECKERS(ClassType, OBJ_NAME, TYPENAME)
+
 /**
  * OBJECT_DECLARE_TYPE:
  * @InstanceType: instance struct name
@@ -574,20 +630,8 @@ struct Object
     \
     G_DEFINE_AUTOPTR_CLEANUP_FUNC(InstanceType, object_unref) \
     \
-    static inline G_GNUC_UNUSED ClassType * \
-    MODULE_OBJ_NAME##_GET_CLASS(void *obj) \
-    { return OBJECT_GET_CLASS(ClassType, obj, \
-                              TYPE_##MODULE_OBJ_NAME); } \
-    \
-    static inline G_GNUC_UNUSED ClassType * \
-    MODULE_OBJ_NAME##_CLASS(void *klass) \
-    { return OBJECT_CLASS_CHECK(ClassType, klass, \
-                                TYPE_##MODULE_OBJ_NAME); } \
-    \
-    static inline G_GNUC_UNUSED InstanceType * \
-    MODULE_OBJ_NAME(void *obj) \
-    { return OBJECT_CHECK(InstanceType, obj, \
-                          TYPE_##MODULE_OBJ_NAME); }
+    DECLARE_OBJ_CHECKERS(InstanceType, ClassType, \
+                         MODULE_OBJ_NAME, TYPE_##MODULE_OBJ_NAME)
 
 /**
  * OBJECT_DECLARE_SIMPLE_TYPE: