object: add object_property_set_default

Add a default value to ObjectProperty and an implementation of
ObjectPropertyInit that uses it.  This will make it easier to show the
default in help messages.

Also provide convenience functions object_property_set_default_{bool,
str, int, uint}().

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20200110153039.1379601-11-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/include/qom/object.h b/include/qom/object.h
index afe658c969..82cf20f441 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -378,6 +378,7 @@ struct ObjectProperty
     ObjectPropertyRelease *release;
     ObjectPropertyInit *init;
     void *opaque;
+    QObject *defval;
 };
 
 /**
@@ -1056,6 +1057,42 @@ ObjectProperty *object_class_property_add(ObjectClass *klass, const char *name,
                                           void *opaque, Error **errp);
 
 /**
+ * object_property_set_default_bool:
+ * @prop: the property to set
+ * @value: the value to be written to the property
+ *
+ * Set the property default value.
+ */
+void object_property_set_default_bool(ObjectProperty *prop, bool value);
+
+/**
+ * object_property_set_default_str:
+ * @prop: the property to set
+ * @value: the value to be written to the property
+ *
+ * Set the property default value.
+ */
+void object_property_set_default_str(ObjectProperty *prop, const char *value);
+
+/**
+ * object_property_set_default_int:
+ * @prop: the property to set
+ * @value: the value to be written to the property
+ *
+ * Set the property default value.
+ */
+void object_property_set_default_int(ObjectProperty *prop, int64_t value);
+
+/**
+ * object_property_set_default_uint:
+ * @prop: the property to set
+ * @value: the value to be written to the property
+ *
+ * Set the property default value.
+ */
+void object_property_set_default_uint(ObjectProperty *prop, uint64_t value);
+
+/**
  * object_property_find:
  * @obj: the object
  * @name: the name of the property