[PATCH 24/26] qom: introduce object_property_help()

[Marc-André Lureau]

Let's factor out the code to format a help string for a property. We
are going to reuse it in qdev next, which will bring some consistency.

Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com>
---
 include/qom/object.h    | 14 ++++++++++++++
 qom/object_interfaces.c | 39 +++++++++++++++++++++++----------------
 2 files changed, 37 insertions(+), 16 deletions(-)

diff --git a/include/qom/object.h b/include/qom/object.h
index aa2cf1ca75..adbccb7705 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -1834,4 +1834,18 @@ Object *container_get(Object *root, const char *path);
  * Returns the instance_size of the given @typename.
  */
 size_t object_type_get_instance_size(const char *typename);
+
+/**
+ * object_property_help:
+ * @name: the name of the property
+ * @type: the type of the property
+ * @defval: the default value
+ * @description: description of the property
+ *
+ * Returns: a user-friendly formatted string describing the property
+ * for help purposes.
+ */
+char *object_property_help(const char *name, const char *type,
+                           const char *defval, const char *description);
+
 #endif
diff --git a/qom/object_interfaces.c b/qom/object_interfaces.c
index edb4cc4a3d..b7157d6ab0 100644
--- a/qom/object_interfaces.c
+++ b/qom/object_interfaces.c
@@ -158,6 +158,25 @@ int user_creatable_add_opts_foreach(void *opaque, QemuOpts 
*opts, Error **errp)
     return 0;
 }
 
+char *object_property_help(const char *name, const char *type,
+                           const char *defval, const char *description)
+{
+    GString *str = g_string_new(NULL);
+
+    g_string_append_printf(str, "  %s=<%s>", name, type);
+    if (defval) {
+        g_string_append_printf(str, " (default: %s)", defval);
+    }
+    if (description) {
+        if (str->len < 24) {
+            g_string_append_printf(str, "%*s", 24 - (int)str->len, "");
+        }
+        g_string_append_printf(str, " - %s", description);
+    }
+
+    return g_string_free(str, false);
+}
+
 bool user_creatable_print_help(const char *type, QemuOpts *opts)
 {
     ObjectClass *klass;
@@ -184,27 +203,15 @@ bool user_creatable_print_help(const char *type, QemuOpts 
*opts)
 
         object_class_property_iter_init(&iter, klass);
         while ((prop = object_property_iter_next(&iter))) {
-            GString *str;
-            char *defval;
+            g_autofree char *defval = object_property_get_default(prop);
 
             if (!prop->set) {
                 continue;
             }
 
-            str = g_string_new(NULL);
-            g_string_append_printf(str, "  %s=<%s>", prop->name, prop->type);
-            defval = object_property_get_default(prop);
-            if (defval) {
-                g_string_append_printf(str, " (default: %s)", defval);
-                g_free(defval);
-            }
-            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_add(array,
+                            object_property_help(prop->name, prop->type,
+                                                 defval, prop->description));
         }
         g_ptr_array_sort(array, (GCompareFunc)qemu_pstrcmp0);
         if (array->len > 0) {
-- 
2.24.0