qom: Add check() argument to object_property_add_link()

There are currently three types of object_property_add_link() callers:

1. The link property may be set at any time.
2. The link property of a DeviceState instance may only be set before
   realize.
3. The link property may never be set, it is read-only.

Something similar can already be achieved with
object_property_add_str()'s set() argument.  Follow its example and add
a check() argument to object_property_add_link().

Also provide default check() functions for case #1 and #2.  Case #3 is
covered by passing a NULL function pointer.

Cc: Peter Crosthwaite <peter.crosthwaite@petalogix.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: Anthony Liguori <aliguori@amazon.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
[AF: Tweaked documentation comment]
Signed-off-by: Andreas Färber <afaerber@suse.de>
This commit is contained in:
Stefan Hajnoczi 2014-03-19 08:58:56 +01:00 committed by Andreas Färber
parent 9561fda8d9
commit 39f72ef94b
13 changed files with 80 additions and 4 deletions

View file

@ -1072,12 +1072,23 @@ typedef enum {
OBJ_PROP_LINK_UNREF_ON_RELEASE = 0x1,
} ObjectPropertyLinkFlags;
/**
* object_property_allow_set_link:
*
* The default implementation of the object_property_add_link() check()
* callback function. It allows the link property to be set and never returns
* an error.
*/
void object_property_allow_set_link(Object *, const char *,
Object *, Error **);
/**
* object_property_add_link:
* @obj: the object to add a property to
* @name: the name of the property
* @type: the qobj type of the link
* @child: a pointer to where the link object reference is stored
* @check: callback to veto setting or NULL if the property is read-only
* @flags: additional options for the link
* @errp: if an error occurs, a pointer to an area to store the area
*
@ -1087,6 +1098,11 @@ typedef enum {
*
* Links form the graph in the object model.
*
* The <code>@check()</code> callback is invoked when
* object_property_set_link() is called and can raise an error to prevent the
* link being set. If <code>@check</code> is NULL, the property is read-only
* and cannot be set.
*
* Ownership of the pointer that @child points to is transferred to the
* link property. The reference count for <code>*@child</code> is
* managed by the property from after the function returns till the
@ -1096,6 +1112,8 @@ typedef enum {
*/
void object_property_add_link(Object *obj, const char *name,
const char *type, Object **child,
void (*check)(Object *obj, const char *name,
Object *val, Error **errp),
ObjectPropertyLinkFlags flags,
Error **errp);