qom: Add user_creatable_print_help_from_qdict()

This adds a function that, given a QDict of non-help options, prints
help for user creatable objects.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20201007164903.282198-4-kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

diff --git a/include/qom/object_interfaces.h b/include/qom/object_interfaces.h
index f118fb5..07d5cc8 100644 (file)
--- a/include/qom/object_interfaces.h
+++ b/include/qom/object_interfaces.h
@@ -154,14 +154,29 @@ int user_creatable_add_opts_foreach(void *opaque,
  * @type: the QOM type to be added
  * @opts: options to create
  *
- * Prints help if requested in @opts.
+ * Prints help if requested in @type or @opts. Note that if @type is neither
+ * "help"/"?" nor a valid user creatable type, no help will be printed
+ * regardless of @opts.
  *
- * Returns: true if @opts contained a help option and help was printed, false
- * if no help option was found.
+ * Returns: true if a help option was found and help was printed, false
+ * otherwise.
  */
 bool user_creatable_print_help(const char *type, QemuOpts *opts);
 
 /**
+ * user_creatable_print_help_from_qdict:
+ * @args: options to create
+ *
+ * Prints help considering the other options given in @args (if "qom-type" is
+ * given and valid, print properties for the type, otherwise print valid types)
+ *
+ * In contrast to user_creatable_print_help(), this function can't return that
+ * no help was requested. It should only be called if we know that help is
+ * requested and it will always print some help.
+ */
+void user_creatable_print_help_from_qdict(QDict *args);
+
+/**
  * user_creatable_del:
  * @id: the unique ID for the object
  * @errp: if an error occurs, a pointer to an area to store the error

diff --git a/qom/object_interfaces.c b/qom/object_interfaces.c
index 3fd1da1..ed896fe 100644 (file)
--- a/qom/object_interfaces.c
+++ b/qom/object_interfaces.c
@@ -279,6 +279,15 @@ bool user_creatable_print_help(const char *type, QemuOpts *opts)
     return false;
 }
 
+void user_creatable_print_help_from_qdict(QDict *args)
+{
+    const char *type = qdict_get_try_str(args, "qom-type");
+
+    if (!type || !user_creatable_print_type_properites(type)) {
+        user_creatable_print_types();
+    }
+}
+
 bool user_creatable_del(const char *id, Error **errp)
 {
     Object *container;