Re: [Qemu-devel] [PATCH 1/2] qom: add a generic mechanism to resolve paths
On Thu, Jun 5, 2014 at 9:23 PM, Paolo Bonzini wrote:
> It may be desirable to have custom link<> properties that do more
> than just store an object. Even the addition of a "check"
> function is not enough if setting the link has side effects
> or if a non-standard reference counting is preferrable.
>
> Avoid the assumption that the opaque field of a link<> is a
> LinkProperty struct, by adding a generic "resolve" callback
> to ObjectProperty.
>
> Signed-off-by: Paolo Bonzini
> ---
> include/qom/object.h | 49 ++
> qom/object.c | 55
> ++--
> 2 files changed, 85 insertions(+), 19 deletions(-)
>
> diff --git a/include/qom/object.h b/include/qom/object.h
> index a641dcd..f8ab845 100644
> --- a/include/qom/object.h
> +++ b/include/qom/object.h
> @@ -304,6 +304,23 @@ typedef void (ObjectPropertyAccessor)(Object *obj,
>Error **errp);
>
> /**
> + * ObjectPropertyResolve:
> + * @obj: the object that owns the property
> + * @opaque: the opaque registered with the property
> + * @part: the name of the property
> + *
> + * If @path is the path that led to @obj, the function should
> + * return the Object corresponding to "@path/@part". If #NULL
> + * is returned, "@path/@part" is not a valid object path.
> + *
> + * The returned object can also be used as a starting point
> + * to resolve a relative path starting with "@part".
> + */
> +typedef Object *(ObjectPropertyResolve)(Object *obj,
> +void *opaque,
> +const char *part);
> +
> +/**
> * ObjectPropertyRelease:
> * @obj: the object that owns the property
> * @name: the name of the property
> @@ -321,6 +338,7 @@ typedef struct ObjectProperty
> gchar *type;
> ObjectPropertyAccessor *get;
> ObjectPropertyAccessor *set;
> +ObjectPropertyResolve *resolve;
> ObjectPropertyRelease *release;
> void *opaque;
>
> @@ -769,6 +787,37 @@ void object_ref(Object *obj);
> void object_unref(Object *obj);
>
> /**
> + * object_property_add_full:
> + * @obj: the object to add a property to
> + * @name: the name of the property. This can contain any character except
> for
> + * a forward slash. In general, you should use hyphens '-' instead of
> + * underscores '_' when naming properties.
> + * @type: the type name of the property. This namespace is pretty loosely
> + * defined. Sub namespaces are constructed by using a prefix and then
> + * to angle brackets. For instance, the type 'virtio-net-pci' in the
> + * 'link' namespace would be 'link'.
> + * @get: The getter to be called to read a property. If this is NULL, then
> + * the property cannot be read.
> + * @set: the setter to be called to write a property. If this is NULL,
> + * then the property cannot be written.
> + * @resolve: called when the property name is used as part of an object
> + * path. This is meant for cases when you want to have custom link
> + * properties. If it is NULL, the property name cannot be used as part
> + * of a valid object path.
> + * @release: called when the property is removed from the object. This is
> + * meant to allow a property to free its opaque upon object
> + * destruction. This may be NULL.
> + * @opaque: an opaque pointer to pass to the callbacks for the property
> + * @errp: returns an error if this function fails
> + */
> +void object_property_add_full(Object *obj, const char *name, const char
> *type,
> + ObjectPropertyAccessor *get,
> + ObjectPropertyAccessor *set,
> + ObjectPropertyResolve *resolve,
> + ObjectPropertyRelease *release,
> + void *opaque, Error **errp);
> +
> +/**
> * object_property_add:
> * @obj: the object to add a property to
> * @name: the name of the property. This can contain any character except
> for
> diff --git a/qom/object.c b/qom/object.c
> index e42b254..fcdd0da 100644
> --- a/qom/object.c
> +++ b/qom/object.c
> @@ -355,11 +355,6 @@ static inline bool
> object_property_is_child(ObjectProperty *prop)
> return strstart(prop->type, "child<", NULL);
> }
>
> -static inline bool object_property_is_link(ObjectProperty *prop)
> -{
> -return strstart(prop->type, "link<", NULL);
> -}
> -
> static void object_property_del_all(Object *obj)
> {
> while (!QTAILQ_EMPTY(&obj->properties)) {
> @@ -727,9 +722,10 @@ void object_unref(Object *obj)
> }
> }
>
> -void object_property_add(Object *obj, const char *name, const char *type,
> +void object_property_add_full(Object *obj, const char *name, const char
> *type,
> ObjectPropertyAccessor *get,
> ObjectPropertyAccessor *set,
> + ObjectPropertyResolve *resolve,
> ObjectPropertyRe
[Qemu-devel] [PATCH 1/2] qom: add a generic mechanism to resolve paths
It may be desirable to have custom link<> properties that do more
than just store an object. Even the addition of a "check"
function is not enough if setting the link has side effects
or if a non-standard reference counting is preferrable.
Avoid the assumption that the opaque field of a link<> is a
LinkProperty struct, by adding a generic "resolve" callback
to ObjectProperty.
Signed-off-by: Paolo Bonzini
---
include/qom/object.h | 49 ++
qom/object.c | 55 ++--
2 files changed, 85 insertions(+), 19 deletions(-)
diff --git a/include/qom/object.h b/include/qom/object.h
index a641dcd..f8ab845 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -304,6 +304,23 @@ typedef void (ObjectPropertyAccessor)(Object *obj,
Error **errp);
/**
+ * ObjectPropertyResolve:
+ * @obj: the object that owns the property
+ * @opaque: the opaque registered with the property
+ * @part: the name of the property
+ *
+ * If @path is the path that led to @obj, the function should
+ * return the Object corresponding to "@path/@part". If #NULL
+ * is returned, "@path/@part" is not a valid object path.
+ *
+ * The returned object can also be used as a starting point
+ * to resolve a relative path starting with "@part".
+ */
+typedef Object *(ObjectPropertyResolve)(Object *obj,
+void *opaque,
+const char *part);
+
+/**
* ObjectPropertyRelease:
* @obj: the object that owns the property
* @name: the name of the property
@@ -321,6 +338,7 @@ typedef struct ObjectProperty
gchar *type;
ObjectPropertyAccessor *get;
ObjectPropertyAccessor *set;
+ObjectPropertyResolve *resolve;
ObjectPropertyRelease *release;
void *opaque;
@@ -769,6 +787,37 @@ void object_ref(Object *obj);
void object_unref(Object *obj);
/**
+ * object_property_add_full:
+ * @obj: the object to add a property to
+ * @name: the name of the property. This can contain any character except for
+ * a forward slash. In general, you should use hyphens '-' instead of
+ * underscores '_' when naming properties.
+ * @type: the type name of the property. This namespace is pretty loosely
+ * defined. Sub namespaces are constructed by using a prefix and then
+ * to angle brackets. For instance, the type 'virtio-net-pci' in the
+ * 'link' namespace would be 'link'.
+ * @get: The getter to be called to read a property. If this is NULL, then
+ * the property cannot be read.
+ * @set: the setter to be called to write a property. If this is NULL,
+ * then the property cannot be written.
+ * @resolve: called when the property name is used as part of an object
+ * path. This is meant for cases when you want to have custom link
+ * properties. If it is NULL, the property name cannot be used as part
+ * of a valid object path.
+ * @release: called when the property is removed from the object. This is
+ * meant to allow a property to free its opaque upon object
+ * destruction. This may be NULL.
+ * @opaque: an opaque pointer to pass to the callbacks for the property
+ * @errp: returns an error if this function fails
+ */
+void object_property_add_full(Object *obj, const char *name, const char *type,
+ ObjectPropertyAccessor *get,
+ ObjectPropertyAccessor *set,
+ ObjectPropertyResolve *resolve,
+ ObjectPropertyRelease *release,
+ void *opaque, Error **errp);
+
+/**
* object_property_add:
* @obj: the object to add a property to
* @name: the name of the property. This can contain any character except for
diff --git a/qom/object.c b/qom/object.c
index e42b254..fcdd0da 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -355,11 +355,6 @@ static inline bool object_property_is_child(ObjectProperty
*prop)
return strstart(prop->type, "child<", NULL);
}
-static inline bool object_property_is_link(ObjectProperty *prop)
-{
-return strstart(prop->type, "link<", NULL);
-}
-
static void object_property_del_all(Object *obj)
{
while (!QTAILQ_EMPTY(&obj->properties)) {
@@ -727,9 +722,10 @@ void object_unref(Object *obj)
}
}
-void object_property_add(Object *obj, const char *name, const char *type,
+void object_property_add_full(Object *obj, const char *name, const char *type,
ObjectPropertyAccessor *get,
ObjectPropertyAccessor *set,
+ ObjectPropertyResolve *resolve,
ObjectPropertyRelease *release,
void *opaque, Error **errp)
{
@@ -751,12 +747,23 @@ void object_property_add(Object *obj, const char *name,
const char *type,
prop->get = get;
prop->set = set;
+prop->resolve = resolve;
prop->release = release;
prop->o
