[PATCH v3 25/30] qom: Add user_creatable_add_from_str()

[Kevin Wolf <kwolf@redhat.com>]

This is a version of user_creatable_process_cmdline() with an Error
parameter that never calls exit() and is therefore usable in HMP.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 include/qom/object_interfaces.h | 16 ++++++++++++++++
 qom/object_interfaces.c         | 29 ++++++++++++++++++++++++-----
 2 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/include/qom/object_interfaces.h b/include/qom/object_interfaces.h
index 1e6c51b541..07511e6cff 100644
--- a/include/qom/object_interfaces.h
+++ b/include/qom/object_interfaces.h
@@ -144,6 +144,22 @@ typedef bool (*user_creatable_add_opts_predicate)(const char *type);
 int user_creatable_add_opts_foreach(void *opaque,
                                     QemuOpts *opts, Error **errp);
 
+/**
+ * user_creatable_add_from_str:
+ * @optarg: the object definition string as passed on the command line
+ * @errp: if an error occurs, a pointer to an area to store the error
+ *
+ * Create an instance of the user creatable object by parsing optarg
+ * with a keyval parser and implicit key 'qom-type', converting the
+ * result to ObjectOptions and calling into qmp_object_add().
+ *
+ * If a help option is given, print help instead.
+ *
+ * Returns: true when an object was successfully created, false when an error
+ * occurred (*errp is set then) or help was printed (*errp is not set).
+ */
+bool user_creatable_add_from_str(const char *optarg, Error **errp);
+
 /**
  * user_creatable_process_cmdline:
  * @optarg: the object definition string as passed on the command line
diff --git a/qom/object_interfaces.c b/qom/object_interfaces.c
index 2eaf9971f5..bf9f8cd2c6 100644
--- a/qom/object_interfaces.c
+++ b/qom/object_interfaces.c
@@ -291,26 +291,45 @@ static void user_creatable_print_help_from_qdict(QDict *args)
     }
 }
 
-void user_creatable_process_cmdline(const char *optarg)
+bool user_creatable_add_from_str(const char *optarg, Error **errp)
 {
+    ERRP_GUARD();
     QDict *args;
     bool help;
     Visitor *v;
     ObjectOptions *options;
 
-    args = keyval_parse(optarg, "qom-type", &help, &error_fatal);
+    args = keyval_parse(optarg, "qom-type", &help, errp);
+    if (*errp) {
+        return false;
+    }
     if (help) {
         user_creatable_print_help_from_qdict(args);
-        exit(EXIT_SUCCESS);
+        qobject_unref(args);
+        return false;
     }
 
     v = qobject_input_visitor_new_keyval(QOBJECT(args));
-    visit_type_ObjectOptions(v, NULL, &options, &error_fatal);
+    visit_type_ObjectOptions(v, NULL, &options, errp);
     visit_free(v);
     qobject_unref(args);
 
-    user_creatable_add_qapi(options, &error_fatal);
+    if (*errp) {
+        goto out;
+    }
+
+    user_creatable_add_qapi(options, errp);
+out:
     qapi_free_ObjectOptions(options);
+    return !*errp;
+}
+
+void user_creatable_process_cmdline(const char *optarg)
+{
+    if (!user_creatable_add_from_str(optarg, &error_fatal)) {
+        /* Help was printed */
+        exit(EXIT_SUCCESS);
+    }
 }
 
 bool user_creatable_del(const char *id, Error **errp)
-- 
2.29.2