A QOM property can be parsed as enum using the visit_type_enum()
helper method, 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;
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->endpoint = value;
}
object_property_add_enum(obj, "devtype",
mydevtypemap,
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 <berra...@redhat.com>
---
include/qom/object.h | 17 ++++++++++++++++
qom/object.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 74 insertions(+)
diff --git a/include/qom/object.h b/include/qom/object.h
index dfdba2f..3462821 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -1262,6 +1262,23 @@ void object_property_add_bool(Object *obj, const char
*name,
Error **errp);
/**
+ * object_property_add_enum:
+ * @obj: the object to add a property to
+ * @name: the name of the property
+ * @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 a enum property using getters/setters. This function will add a
+ * property of type 'enum'.
+ */
+void object_property_add_enum(Object *obj, const char *name,
+ 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
* @name: the name of the property
diff --git a/qom/object.c b/qom/object.c
index 2534398..543cc57 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -1607,6 +1607,63 @@ void object_property_add_bool(Object *obj, const char
*name,
}
}
+typedef struct EnumProperty {
+ const char * const *strings;
+ int (*get)(Object *, Error **);
+ void (*set)(Object *, int, Error **);
+} EnumProperty;
+
+static void property_get_enum(Object *obj, Visitor *v, void *opaque,
+ const char *name, Error **errp)
+{
+ EnumProperty *prop = opaque;
+ int value;
+
+ value = prop->get(obj, errp);
+ visit_type_enum(v, &value, prop->strings, NULL, name, errp);
+}
+
+static void property_set_enum(Object *obj, Visitor *v, void *opaque,
+ const char *name, Error **errp)
+{
+ EnumProperty *prop = opaque;
+ int value;
+
+ visit_type_enum(v, &value, prop->strings, NULL, name, errp);
+ prop->set(obj, value, errp);
+}
+
+static void property_release_enum(Object *obj, const char *name,
+ void *opaque)
+{
+ EnumProperty *prop = opaque;
+ g_free(prop);
+}
+
+void object_property_add_enum(Object *obj, const char *name,
+ const char * const *strings,
+ int (*get)(Object *, Error **),
+ void (*set)(Object *, int, Error **),
+ Error **errp)
+{
+ Error *local_err = NULL;
+ EnumProperty *prop = g_malloc0(sizeof(*prop));
+
+ prop->strings = strings;
+ prop->get = get;
+ prop->set = set;
+
+ object_property_add(obj, name, "enum",
+ get ? property_get_enum : NULL,
+ set ? property_set_enum : NULL,
+ property_release_enum,
+ prop, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ g_free(prop);
+ }
+}
+
typedef struct TMProperty {
void (*get)(Object *, struct tm *, Error **);
} TMProperty;
--
2.1.0
