motorhead/qemu
1
0
Fork 0
mirror of https://github.com/Motorhead1991/qemu.git synced 2025-08-01 23:03:54 -06:00
Code Issues Projects Releases Packages Wiki Activity Actions

qom: Add an object_property_add_enum() helper function

Browse source 
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>
This commit is contained in:
Daniel P. Berrange 2015-05-13 17:14:08 +01:00 • committed by Andreas Färber
parent 2e4450ff43
commit a8e3fbedc8
3 changed files with 150 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

19
include/qom/object.h
View file

@ -1343,6 +1343,25 @@ void object_property_add_bool(Object *obj, const char *name,
void (*set)(Object *, bool, Error **),
Error **errp);
/**
* object_property_add_enum:
* @obj: the object to add a property to
* @name: the name of the property
* @typename: the name of the enum data type
* @get: the getter or %NULL if the property is write-only.
* @set: the setter or %NULL if the property is read-only
* @errp: if an error occurs, a pointer to an area to store the error
*
* Add an enum property using getters/setters. This function will add a
* property of type '@typename'.
*/
void object_property_add_enum(Object *obj, const char *name,
const char *typename,
const char * const *strings,
int (*get)(Object *, Error **),
void (*set)(Object *, int, Error **),
Error **errp);
/**
* object_property_add_tm:
* @obj: the object to add a property to