diff options
author | Daniel P. Berrange <berrange@redhat.com> | 2015-05-13 17:14:06 +0100 |
---|---|---|
committer | Andreas Färber <afaerber@suse.de> | 2015-06-19 18:42:18 +0200 |
commit | a31bdae5a76ecc060c1eb8a66be1896072c1e8b2 (patch) | |
tree | f09410fa5d0fbdb196e461be8662c57ec4e9ff6f /include/qom | |
parent | bc2256c4ae86308a1521c89456b599d441119418 (diff) | |
download | qemu-a31bdae5a76ecc060c1eb8a66be1896072c1e8b2.zip qemu-a31bdae5a76ecc060c1eb8a66be1896072c1e8b2.tar.gz qemu-a31bdae5a76ecc060c1eb8a66be1896072c1e8b2.tar.bz2 |
qom: Add object_new_with_props() / object_new_withpropv() helpers
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>
Diffstat (limited to 'include/qom')
-rw-r--r-- | include/qom/object.h | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/include/qom/object.h b/include/qom/object.h index b03ede0..018e27e 100644 --- a/include/qom/object.h +++ b/include/qom/object.h @@ -607,6 +607,134 @@ Object *object_new(const char *typename); Object *object_new_with_type(Type type); /** + * object_new_with_props: + * @typename: The name of the type of the object to instantiate. + * @parent: the parent object + * @id: The unique ID of the object + * @errp: pointer to error object + * @...: list of property names and values + * + * This function will initialize a new object using heap allocated memory. + * The returned object has a reference count of 1, and will be freed when + * the last reference is dropped. + * + * The @id parameter will be used when registering the object as a + * child of @parent in the composition tree. + * + * The variadic parameters are a list of pairs of (propname, propvalue) + * strings. The propname of %NULL indicates the end of the property + * list. If the object implements the user creatable interface, the + * object will be marked complete once all the properties have been + * processed. + * + * <example> + * <title>Creating an object with properties</title> + * <programlisting> + * Error *err = NULL; + * Object *obj; + * + * obj = object_new_with_props(TYPE_MEMORY_BACKEND_FILE, + * object_get_objects_root(), + * "hostmem0", + * &err, + * "share", "yes", + * "mem-path", "/dev/shm/somefile", + * "prealloc", "yes", + * "size", "1048576", + * NULL); + * + * if (!obj) { + * g_printerr("Cannot create memory backend: %s\n", + * error_get_pretty(err)); + * } + * </programlisting> + * </example> + * + * The returned object will have one stable reference maintained + * for as long as it is present in the object hierarchy. + * + * Returns: The newly allocated, instantiated & initialized object. + */ +Object *object_new_with_props(const char *typename, + Object *parent, + const char *id, + Error **errp, + ...) QEMU_SENTINEL; + +/** + * object_new_with_propv: + * @typename: The name of the type of the object to instantiate. + * @parent: the parent object + * @id: The unique ID of the object + * @errp: pointer to error object + * @vargs: list of property names and values + * + * See object_new_with_props() for documentation. + */ +Object *object_new_with_propv(const char *typename, + Object *parent, + const char *id, + Error **errp, + va_list vargs); + +/** + * object_set_props: + * @obj: the object instance to set properties on + * @errp: pointer to error object + * @...: list of property names and values + * + * This function will set a list of properties on an existing object + * instance. + * + * The variadic parameters are a list of pairs of (propname, propvalue) + * strings. The propname of %NULL indicates the end of the property + * list. + * + * <example> + * <title>Update an object's properties</title> + * <programlisting> + * Error *err = NULL; + * Object *obj = ...get / create object...; + * + * obj = object_set_props(obj, + * &err, + * "share", "yes", + * "mem-path", "/dev/shm/somefile", + * "prealloc", "yes", + * "size", "1048576", + * NULL); + * + * if (!obj) { + * g_printerr("Cannot set properties: %s\n", + * error_get_pretty(err)); + * } + * </programlisting> + * </example> + * + * The returned object will have one stable reference maintained + * for as long as it is present in the object hierarchy. + * + * Returns: -1 on error, 0 on success + */ +int object_set_props(Object *obj, + Error **errp, + ...) QEMU_SENTINEL; + +/** + * object_set_propv: + * @obj: the object instance to set properties on + * @errp: pointer to error object + * @vargs: list of property names and values + * + * See object_set_props() for documentation. + * + * Returns: -1 on error, 0 on success + */ +int object_set_propv(Object *obj, + Error **errp, + va_list vargs); + +/** * object_initialize_with_type: * @data: A pointer to the memory to be used for the object. * @size: The maximum size available at @data for the object. |