@samitouri / QOSamiQemu / commits / 23ece6f887

qom/object: Add object_resolve_and_typecheck()

Add a new function object_resolve_and_typecheck(), whose purpose is to look up the object at a given QOM path, confirm that it is the expected type, and return it. This is similar to the existing object_resolve_path_type(), but it insists on a non-ambiguous path. We were already using this functionality internally to object.c as part of the object_resolve_link() function, so this patch implements the new function by pulling the link-property specific parts out of the more generic resolve-and-typecheck part. The motivation for this function is that we want to allow devices to provide an array of link properties; for that we will need to be able to provide the expected type of the linked object in a different way to the single-item link properties. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 20260327111700.795099-2-peter.maydell@linaro.org

Peter Maydell committed Mar 27, 2026 at 11:15 UTC 23ece6f88752167296c9525f15ef5935a469d374

2 files changed +40 -18

include/qom/object.h

+17

@@ -1742,6 +1742,23 @@ ObjectProperty *object_class_property_add_link(ObjectClass *oc,

1742 Object *val, Error **errp),

1743 ObjectPropertyLinkFlags flags);

1744

1745 +/**

1746 + * object_resolve_and_typecheck:

1747 + * @path: path to look up

1748 + * @name: name of property we are resolving for (used only in error messages)

1749 + * @target_type: QOM type we expect @path to resolve to

1750 + * @errp: error

1751 + *

1752 + * Look up the object at @path and return it. If it does not have the

1753 + * correct type @target_type, return NULL and set @errp.

1754 + *

1755 + * This is similar to object_resolve_path_type(), but it insists on a

1756 + * non-ambiguous path and it produces error messages that are

1757 + * specialised to the use case of setting a link property on an object.

1758 + */

1759 +Object *object_resolve_and_typecheck(const char *path, const char *name,

1760 + const char *target_type, Error **errp);

1761 +

1762 /**

1763 * object_property_add_str:

1764 * @obj: the object to add a property to

qom/object.c

+23 -18

@@ -1835,26 +1835,12 @@ static void object_get_link_property(Object *obj, Visitor *v,

1835 }

1836 }

1837

1838 -/*

1839 - * object_resolve_link:

1840 - *

1841 - * Lookup an object and ensure its type matches the link property type. This

1842 - * is similar to object_resolve_path() except type verification against the

1843 - * link property is performed.

1844 - *

1845 - * Returns: The matched object or NULL on path lookup failures.

1846 - */

1847 -static Object *object_resolve_link(Object *obj, const char *name,

1848 - const char *path, Error **errp)

1838 +Object *object_resolve_and_typecheck(const char *path, const char *name,

1839 + const char *target_type, Error **errp)

1840 {

1850 - const char *type;

1851 - char *target_type;

1841 bool ambiguous = false;

1842 Object *target;

1843

1855 - /* Go from link<FOO> to FOO. */

1856 - type = object_property_get_type(obj, name, NULL);

1857 - target_type = g_strndup(&type[5], strlen(type) - 6);

1844 target = object_resolve_path_type(path, target_type, &ambiguous);

1845

1846 if (ambiguous) {

@@ -1871,11 +1857,30 @@ static Object *object_resolve_link(Object *obj, const char *name,

1857 }

1858 target = NULL;

1859 }

1874 - g_free(target_type);

1875 -

1860 return target;

1861 }

1862

1863 +/*

1864 + * object_resolve_link:

1865 + *

1866 + * Lookup an object and ensure its type matches the link property type. This

1867 + * is similar to object_resolve_path() except type verification against the

1868 + * link property is performed.

1869 + *

1870 + * Returns: The matched object or NULL on path lookup failures.

1871 + */

1872 +static Object *object_resolve_link(Object *obj, const char *name,

1873 + const char *path, Error **errp)

1874 +{

1875 + const char *type;

1876 + g_autofree char *target_type = NULL;

1877 +

1878 + /* Go from link<FOO> to FOO. */

1879 + type = object_property_get_type(obj, name, NULL);

1880 + target_type = g_strndup(&type[5], strlen(type) - 6);

1881 + return object_resolve_and_typecheck(path, name, target_type, errp);

1882 +}

1883 +

1884 static void object_set_link_property(Object *obj, Visitor *v,

1885 const char *name, void *opaque,

1886 Error **errp)