vl: Split off user_creatable_print_help()

Printing help for --object is something that we not only want in the
system emulator, but also in tools that support --object. Move it into a
separate function in qom/object_interfaces.c to make the code accessible
for tools.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

include/qom/object_interfaces.h

@@ -132,6 +132,18 @@ typedef bool (*user_creatable_add_opts_predicate)(const char *type);
 int user_creatable_add_opts_foreach(void *opaque,
                                     QemuOpts *opts, Error **errp);
 
+/**
+ * user_creatable_print_help:
+ * @type: the QOM type to be added
+ * @opts: options to create
+ *
+ * Prints help if requested in @opts.
+ *
+ * Returns: true if @opts contained a help option and help was printed, false
+ * if no help option was found.
+ */
+bool user_creatable_print_help(const char *type, QemuOpts *opts);
+
 /**
  * user_creatable_del:
  * @id: the unique ID for the object

qom/object_interfaces.c

@@ -1,8 +1,11 @@
 #include "qemu/osdep.h"
+
+#include "qemu/cutils.h"
 #include "qapi/error.h"
 #include "qapi/qmp/qdict.h"
 #include "qapi/qmp/qerror.h"
 #include "qom/object_interfaces.h"
+#include "qemu/help_option.h"
 #include "qemu/module.h"
 #include "qemu/option.h"
 #include "qapi/opts-visitor.h"
@@ -155,6 +158,64 @@ int user_creatable_add_opts_foreach(void *opaque, QemuOpts *opts, Error **errp)
     return 0;
 }
 
+bool user_creatable_print_help(const char *type, QemuOpts *opts)
+{
+    ObjectClass *klass;
+
+    if (is_help_option(type)) {
+        GSList *l, *list;
+
+        printf("List of user creatable objects:\n");
+        list = object_class_get_list_sorted(TYPE_USER_CREATABLE, false);
+        for (l = list; l != NULL; l = l->next) {
+            ObjectClass *oc = OBJECT_CLASS(l->data);
+            printf("  %s\n", object_class_get_name(oc));
+        }
+        g_slist_free(list);
+        return true;
+    }
+
+    klass = object_class_by_name(type);
+    if (klass && qemu_opt_has_help_opt(opts)) {
+        ObjectPropertyIterator iter;
+        ObjectProperty *prop;
+        GPtrArray *array = g_ptr_array_new();
+        int i;
+
+        object_class_property_iter_init(&iter, klass);
+        while ((prop = object_property_iter_next(&iter))) {
+            GString *str;
+
+            if (!prop->set) {
+                continue;
+            }
+
+            str = g_string_new(NULL);
+            g_string_append_printf(str, "  %s=<%s>", prop->name, prop->type);
+            if (prop->description) {
+                if (str->len < 24) {
+                    g_string_append_printf(str, "%*s", 24 - (int)str->len, "");
+                }
+                g_string_append_printf(str, " - %s", prop->description);
+            }
+            g_ptr_array_add(array, g_string_free(str, false));
+        }
+        g_ptr_array_sort(array, (GCompareFunc)qemu_pstrcmp0);
+        if (array->len > 0) {
+            printf("%s options:\n", type);
+        } else {
+            printf("There are no options for %s.\n", type);
+        }
+        for (i = 0; i < array->len; i++) {
+            printf("%s\n", (char *)array->pdata[i]);
+        }
+        g_ptr_array_set_free_func(array, g_free);
+        g_ptr_array_free(array, true);
+        return true;
+    }
+
+    return false;
+}
 
 void user_creatable_del(const char *id, Error **errp)
 {

vl.c

@@ -2649,57 +2649,7 @@ static int machine_set_property(void *opaque,
  */
 static bool object_create_initial(const char *type, QemuOpts *opts)
 {
-    ObjectClass *klass;
+    if (user_creatable_print_help(type, opts)) {
-
-    if (is_help_option(type)) {
-        GSList *l, *list;
-
-        printf("List of user creatable objects:\n");
-        list = object_class_get_list_sorted(TYPE_USER_CREATABLE, false);
-        for (l = list; l != NULL; l = l->next) {
-            ObjectClass *oc = OBJECT_CLASS(l->data);
-            printf("  %s\n", object_class_get_name(oc));
-        }
-        g_slist_free(list);
-        exit(0);
-    }
-
-    klass = object_class_by_name(type);
-    if (klass && qemu_opt_has_help_opt(opts)) {
-        ObjectPropertyIterator iter;
-        ObjectProperty *prop;
-        GPtrArray *array = g_ptr_array_new();
-        int i;
-
-        object_class_property_iter_init(&iter, klass);
-        while ((prop = object_property_iter_next(&iter))) {
-            GString *str;
-
-            if (!prop->set) {
-                continue;
-            }
-
-            str = g_string_new(NULL);
-            g_string_append_printf(str, "  %s=<%s>", prop->name, prop->type);
-            if (prop->description) {
-                if (str->len < 24) {
-                    g_string_append_printf(str, "%*s", 24 - (int)str->len, "");
-                }
-                g_string_append_printf(str, " - %s", prop->description);
-            }
-            g_ptr_array_add(array, g_string_free(str, false));
-        }
-        g_ptr_array_sort(array, (GCompareFunc)qemu_pstrcmp0);
-        if (array->len > 0) {
-            printf("%s options:\n", type);
-        } else {
-            printf("There are no options for %s.\n", type);
-        }
-        for (i = 0; i < array->len; i++) {
-            printf("%s\n", (char *)array->pdata[i]);
-        }
-        g_ptr_array_set_free_func(array, g_free);
-        g_ptr_array_free(array, true);
         exit(0);
     }