To move towards explicit creations of containers, starting that by
providing a helper for creating container objects.
Signed-off-by: Peter Xu <peterx@redhat.com>
---
include/qom/object.h | 12 ++++++++++++
qom/container.c | 18 +++++++++++++++---
2 files changed, 27 insertions(+), 3 deletions(-)
diff --git a/include/qom/object.h b/include/qom/object.h
index 3ba370ce9b..41ef53241e 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -2033,6 +2033,18 @@ int object_child_foreach_recursive(Object *obj,
*/
Object *container_get(Object *root, const char *path);
+
+/**
+ * container_create:
+ * @root: root of the object to create the new container
+ * @name: name of the new container
+ *
+ * Create a container object under @root with @name.
+ *
+ * Returns: the newly created container object.
+ */
+Object *container_create(Object *root, const char *name);
+
/**
* object_property_help:
* @name: the name of the property
diff --git a/qom/container.c b/qom/container.c
index cfec92a944..da657754a4 100644
--- a/qom/container.c
+++ b/qom/container.c
@@ -24,6 +24,20 @@ static void container_register_types(void)
type_register_static(&container_info);
}
+Object *container_create(Object *obj, const char *name)
+{
+ Object *child = object_new(TYPE_CONTAINER);
+
+ object_property_add_child(obj, name, child);
+ /*
+ * Simplify the caller by always drop the refcount directly here, as
+ * containers are normally never destroyed after created anyway.
+ */
+ object_unref(child);
+
+ return child;
+}
+
Object *container_get(Object *root, const char *path)
{
Object *obj, *child;
@@ -37,9 +51,7 @@ Object *container_get(Object *root, const char *path)
for (i = 1; parts[i] != NULL; i++, obj = child) {
child = object_resolve_path_component(obj, parts[i]);
if (!child) {
- child = object_new(TYPE_CONTAINER);
- object_property_add_child(obj, parts[i], child);
- object_unref(child);
+ child = container_create(obj, parts[i]);
}
}
--
2.45.0Peter Xu <peterx@redhat.com> writes:
> To move towards explicit creations of containers, starting that by
> providing a helper for creating container objects.
>
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
> include/qom/object.h | 12 ++++++++++++
> qom/container.c | 18 +++++++++++++++---
> 2 files changed, 27 insertions(+), 3 deletions(-)
>
> diff --git a/include/qom/object.h b/include/qom/object.h
> index 3ba370ce9b..41ef53241e 100644
> --- a/include/qom/object.h
> +++ b/include/qom/object.h
> @@ -2033,6 +2033,18 @@ int object_child_foreach_recursive(Object *obj,
> */
> Object *container_get(Object *root, const char *path);
>
> +
> +/**
> + * container_create:
> + * @root: root of the object to create the new container
> + * @name: name of the new container
Is this the name of the property of @root to hold the new container?
Peeking ahead to the implementation... yes.
> + *
> + * Create a container object under @root with @name.
> + *
> + * Returns: the newly created container object.
> + */
> +Object *container_create(Object *root, const char *name);
No function in this file is named like FOO_create(). Hmm.
Compare:
/**
* object_property_try_add_child:
* @obj: the object to add a property to
* @name: the name of the property
* @child: the child object
* @errp: pointer to error object
*
* Child properties form the composition tree. All objects need to be a child
* of another object. Objects can only be a child of one object.
*
* There is no way for a child to determine what its parent is. It is not
* a bidirectional relationship. This is by design.
Aside: this is nonsense. While you're not supposed to simply use
obj->parent (it's documented as private), you can still get the child's
canonical path with object_get_canonical_path(), split off its last
component to get the parent's canonical path, then use
object_resolve_path() to get the parent.
*
* The value of a child property as a C string will be the child object's
* canonical path. It can be retrieved using object_property_get_str().
* The child object itself can be retrieved using object_property_get_link().
*
* Returns: The newly added property on success, or %NULL on failure.
*/
What about
/**
* object_property_add_new_container:
* @obj: the parent object
* @name: the name of the parent object's property to add
*
* Add a newly created container object to a parent object.
*
* Returns: the newly created container object. Its reference count
* is 1, and the reference is owned by the parent object.
*/
> +
> /**
> * object_property_help:
> * @name: the name of the property
> diff --git a/qom/container.c b/qom/container.c
> index cfec92a944..da657754a4 100644
> --- a/qom/container.c
> +++ b/qom/container.c
> @@ -24,6 +24,20 @@ static void container_register_types(void)
> type_register_static(&container_info);
> }
>
> +Object *container_create(Object *obj, const char *name)
> +{
> + Object *child = object_new(TYPE_CONTAINER);
> +
> + object_property_add_child(obj, name, child);
> + /*
> + * Simplify the caller by always drop the refcount directly here, as
> + * containers are normally never destroyed after created anyway.
> + */
> + object_unref(child);
Do we still need the comment if we document the reference count in the
function comment?
> +
> + return child;
> +}
> +
> Object *container_get(Object *root, const char *path)
> {
> Object *obj, *child;
> @@ -37,9 +51,7 @@ Object *container_get(Object *root, const char *path)
> for (i = 1; parts[i] != NULL; i++, obj = child) {
> child = object_resolve_path_component(obj, parts[i]);
> if (!child) {
> - child = object_new(TYPE_CONTAINER);
> - object_property_add_child(obj, parts[i], child);
> - object_unref(child);
> + child = container_create(obj, parts[i]);
> }
> }
On Thu, Nov 21, 2024 at 02:20:44PM +0100, Markus Armbruster wrote:
> Peter Xu <peterx@redhat.com> writes:
>
> > To move towards explicit creations of containers, starting that by
> > providing a helper for creating container objects.
> >
> > Signed-off-by: Peter Xu <peterx@redhat.com>
> > ---
> > include/qom/object.h | 12 ++++++++++++
> > qom/container.c | 18 +++++++++++++++---
> > 2 files changed, 27 insertions(+), 3 deletions(-)
> >
> > diff --git a/include/qom/object.h b/include/qom/object.h
> > index 3ba370ce9b..41ef53241e 100644
> > --- a/include/qom/object.h
> > +++ b/include/qom/object.h
> > @@ -2033,6 +2033,18 @@ int object_child_foreach_recursive(Object *obj,
> > */
> > Object *container_get(Object *root, const char *path);
> >
> > +
> > +/**
> > + * container_create:
> > + * @root: root of the object to create the new container
> > + * @name: name of the new container
>
> Is this the name of the property of @root to hold the new container?
> Peeking ahead to the implementation... yes.
>
> > + *
> > + * Create a container object under @root with @name.
> > + *
> > + * Returns: the newly created container object.
> > + */
> > +Object *container_create(Object *root, const char *name);
>
> No function in this file is named like FOO_create(). Hmm.
>
> Compare:
>
> /**
> * object_property_try_add_child:
> * @obj: the object to add a property to
> * @name: the name of the property
> * @child: the child object
> * @errp: pointer to error object
> *
> * Child properties form the composition tree. All objects need to be a child
> * of another object. Objects can only be a child of one object.
> *
> * There is no way for a child to determine what its parent is. It is not
> * a bidirectional relationship. This is by design.
>
> Aside: this is nonsense. While you're not supposed to simply use
> obj->parent (it's documented as private), you can still get the child's
> canonical path with object_get_canonical_path(), split off its last
> component to get the parent's canonical path, then use
> object_resolve_path() to get the parent.
>
> *
> * The value of a child property as a C string will be the child object's
> * canonical path. It can be retrieved using object_property_get_str().
> * The child object itself can be retrieved using object_property_get_link().
> *
> * Returns: The newly added property on success, or %NULL on failure.
> */
>
> What about
>
> /**
> * object_property_add_new_container:
> * @obj: the parent object
> * @name: the name of the parent object's property to add
> *
> * Add a newly created container object to a parent object.
> *
> * Returns: the newly created container object. Its reference count
> * is 1, and the reference is owned by the parent object.
> */
Sure, this may indeed align better with the rest function names.
>
> > +
> > /**
> > * object_property_help:
> > * @name: the name of the property
> > diff --git a/qom/container.c b/qom/container.c
> > index cfec92a944..da657754a4 100644
> > --- a/qom/container.c
> > +++ b/qom/container.c
> > @@ -24,6 +24,20 @@ static void container_register_types(void)
> > type_register_static(&container_info);
> > }
> >
> > +Object *container_create(Object *obj, const char *name)
> > +{
> > + Object *child = object_new(TYPE_CONTAINER);
> > +
> > + object_property_add_child(obj, name, child);
> > + /*
> > + * Simplify the caller by always drop the refcount directly here, as
> > + * containers are normally never destroyed after created anyway.
> > + */
> > + object_unref(child);
>
> Do we still need the comment if we document the reference count in the
> function comment?
Probably not. I'll drop this comment while taking above suggestion.
Thanks,
--
Peter Xu
On Wed, Nov 20, 2024 at 04:56:53PM -0500, Peter Xu wrote: > To move towards explicit creations of containers, starting that by > providing a helper for creating container objects. > > Signed-off-by: Peter Xu <peterx@redhat.com> > --- > include/qom/object.h | 12 ++++++++++++ > qom/container.c | 18 +++++++++++++++--- > 2 files changed, 27 insertions(+), 3 deletions(-) Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
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