Re: [libvirt] [PATCH v2 04/10] qemu: capabilities: Detect active block commit via QMP schema probing if possible

On Thu, Aug 23, 2018 at 14:45:35 -0400, John Ferlan wrote: [...] Some of them may be selected using the '*' modifier. The modifier is meant to select optional only arguments. For arguments which are not optional or if you don't care if it's optional no modifier still should be used. This is useful only in cases where some argument became optional later on. The documentation for virQEMUCapsQMPSchemaQueries says: /* see documentation for virQEMUQAPISchemaPathGet for the query format */ static struct virQEMUCapsStringFlags virQEMUCapsQMPSchemaQueries[] = { { "blockdev-add/arg-type/options/+gluster/debug-level", QEMU_CAPS_GLUSTER_DEBUG_LEVEL}, { "blockdev-add/arg-type/+gluster/debug", QEMU_CAPS_GLUSTER_DEBUG_LEVEL}, { "blockdev-add/arg-type/+vxhs", QEMU_CAPS_VXHS}, Where we document the format of the query string: /** * virQEMUQAPISchemaPathGet: * @query: string specifying the required data type (see below) * @schema: hash table containing the schema data * @entry: filled with the located schema object requested by @query * * Retrieves the requested schema entry specified by @query to @entry. The * @query parameter has the following syntax which is very closely tied to the * qemu schema syntax entries separated by slashes with a few special characters: * * "command_or_event/attribute/subattribute/+variant_discriminator/subattribute" * * command_or_event: name of the event or attribute to introspect * attribute: selects whether arguments or return type should be introspected * ("arg-type" or "ret-type" for commands, "arg-type" for events) * subattribute: specifies member name of object types * *subattribute: same as above but must be optional (has a property named * 'default' field in the schema) * +variant_discriminator: In the case of unionized objects, select a * specific case to introspect. * * If the name of any (sub)attribute starts with non-alphabetical symbols it * needs to be prefixed by a single space. * * Array types are automatically flattened to the singular type. Alternate * types are currently not supported. * * The above types can be chained arbitrarily using slashes to construct any * path into the schema tree. * * Returns 0 on success (including if the requested schema was not found) and * fills @entry appropriately. On failure returns -1 and sets an appropriate * error message. */