A QOM property can be parsed as enum using the visit_type_enum()
helper function, but this forces callers to use the more complex
generic object_property_add() method when registering it. It
also requires that users of that object have access to the
string map when they want to read the property value.
This patch introduces a specialized object_property_add_enum()
method which simplifies the use of enum properties, so the
setters/getters directly get passed the int value.
typedef enum {
MYDEV_TYPE_FROG,
MYDEV_TYPE_ALLIGATOR,
MYDEV_TYPE_PLATYPUS,
MYDEV_TYPE_LAST
} MyDevType;
Then provide a table of enum <-> string mappings
static const char *const mydevtypemap[MYDEV_TYPE_LAST + 1] = {
[MYDEV_TYPE_FROG] = "frog",
[MYDEV_TYPE_ALLIGATOR] = "alligator",
[MYDEV_TYPE_PLATYPUS] = "platypus",
[MYDEV_TYPE_LAST] = NULL,
};
Assuming an object struct of
typedef struct {
Object parent_obj;
MyDevType devtype;
...other fields...
} MyDev;
The property can then be registered as follows:
static int mydev_prop_get_devtype(Object *obj,
Error **errp G_GNUC_UNUSED)
{
MyDev *dev = MYDEV(obj);
return dev->devtype;
}
static void mydev_prop_set_devtype(Object *obj,
int value,
Error **errp G_GNUC_UNUSED)
{
MyDev *dev = MYDEV(obj);
dev->devtype = value;
}
object_property_add_enum(obj, "devtype",
mydevtypemap, "MyDevType",
mydev_prop_get_devtype,
mydev_prop_set_devtype,
NULL);
Note there is no need to check the range of 'value' in
the setter, because the string->enum conversion code will
have already done that and reported an error as required.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
It is reasonably common to want to create an object, set a
number of properties, register it in the hierarchy and then
mark it as complete (if a user creatable type). This requires
quite a lot of error prone, verbose, boilerplate code to achieve.
First a pair of functions object_set_props() / object_set_propv()
are added which allow for a list of objects to be set in
one single API call.
Then object_new_with_props() / object_new_with_propv() constructors
are added which simplify the sequence of calls to create an
object, populate properties, register in the object composition
tree and mark the object complete, into a single method call.
Usage would be:
Error *err = NULL;
Object *obj;
obj = object_new_with_propv(TYPE_MEMORY_BACKEND_FILE,
object_get_objects_root(),
"hostmem0",
&err,
"share", "yes",
"mem-path", "/dev/shm/somefile",
"prealloc", "yes",
"size", "1048576",
NULL);
Note all property values are passed in string form and will
be parsed into their required data types, using normal QOM
semantics for parsing from string format.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Daniel P. Berrange