feat(object): add public type query APIs

Author: chenglong

include/miniqom/object.h

@@ -23,6 +23,9 @@ void object_free(Object *obj);
 
 bool object_is_instance_of(const Object *obj, const char *type_name);
 
+const char *object_get_type_name(const Object *obj);
+bool object_is_a(const Object *obj, const char *type_name);
+
 bool object_add_child(Object *parent, const char *name,
                       Object *child, Error *err);
 

src/main.c

@@ -16,7 +16,7 @@ static void dump_tree(const Object *obj, unsigned depth)
 
     printf("%s (%s)\n",
            obj->name ? obj->name : "<root>",
-           type_get_info(obj->klass->type)->name);
+           object_get_type_name(obj));
 
     for (size_t i = 0; i < obj->child_count; i++)
     {

src/qom/object.c

@@ -83,9 +83,26 @@ void object_free(Object *obj)
     free(obj);
 }
 
-bool object_is_instance_of(const Object *obj, const char *type_name)
+const char *object_get_type_name(const Object *obj)
+{
+    if (!obj || !obj->klass || !obj->klass->type)
+    {
+        return NULL;
+    }
+
+    return type_get_info(obj->klass->type)->name;
+}
+
+bool object_is_a(const Object *obj, const char *type_name)
 {
-    for (Type *type = obj->klass->type; type; type = type_get_parent(type))
+    Type *type;
+
+    if (!obj || !type_name || !obj->klass || !obj->klass->type)
+    {
+        return false;
+    }
+
+    for (type = obj->klass->type; type; type = type_get_parent(type))
     {
         if (!strcmp(type_get_info(type)->name, type_name))
         {
@@ -96,6 +113,11 @@ bool object_is_instance_of(const Object *obj, const char *type_name)
     return false;
 }
 
+bool object_is_instance_of(const Object *obj, const char *type_name)
+{
+    return object_is_a(obj, type_name);
+}
+
 bool object_add_child(Object *parent, const char *name,
                       Object *child, Error *err)
 {

tests/test_qom.c

@@ -25,6 +25,15 @@ int main(void)
     assert(object_is_instance_of(mem0, TYPE_MEMORY_BACKEND_MEMFD));
     assert(object_is_instance_of(mem0, TYPE_MEMORY_BACKEND));
     assert(object_is_instance_of(mem0, "object"));
+    assert(!strcmp(object_get_type_name(mem0),
+                   TYPE_MEMORY_BACKEND_MEMFD));
+
+    assert(object_is_a(mem0, TYPE_MEMORY_BACKEND_MEMFD));
+    assert(object_is_a(mem0, TYPE_MEMORY_BACKEND));
+    assert(object_is_a(mem0, "object"));
+    assert(!object_is_a(mem0, "unknown-type"));
+    assert(object_get_type_name(NULL) == NULL);
+    assert(!object_is_a(NULL, "object"));
 
     backend = (HostMemoryBackendMemfd *)mem0;
     assert(backend->seal);