Re: [Qemu-devel] [PATCH 01/10] qom: Make object_resolve_path_component() path argument const

["Andreas Färber" <afaerber@suse.de>]

Am 14.01.2013 13:19, schrieb Markus Armbruster:
> Andreas Färber <afaerber@suse.de> writes:
> 
>> This allows to navigate partial well-known paths from an object.
> 
> Why does making the argument const allow such navigation?

Without const, object_resolve_path_component(foo, "bar") results in a
compile error (09/10 accesses "ide[1]" etc. to avoid exposing the full
MacIOState).

Apparently this function was so far only used on dynamically generated
(non-const) arrays:

qom/container.c:        child = object_resolve_path_component(obj,
parts[i]);
qom/object.c:    child = object_resolve_path_component(parent,
parts[index]);

>> Signed-off-by: Andreas Färber <afaerber@suse.de>
>> Cc: Anthony Liguori <anthony@codemonkey.ws>
>> ---
>>  include/qom/object.h |    2 +-
>>  qom/object.c         |    2 +-
>>  2 Dateien geändert, 2 Zeilen hinzugefügt(+), 2 Zeilen entfernt(-)
>>
>> diff --git a/include/qom/object.h b/include/qom/object.h
>> index d43b289..1ef2f0e 100644
>> --- a/include/qom/object.h
>> +++ b/include/qom/object.h
>> @@ -900,7 +900,7 @@ Object *object_resolve_path_type(const char *path, const char *typename,
>>   *
>>   * Returns: The resolved object or NULL on path lookup failure.
>>   */
>> -Object *object_resolve_path_component(Object *parent, gchar *part);
>> +Object *object_resolve_path_component(Object *parent, const gchar *part);
>>  /**
>>   * object_property_add_child:
>> diff --git a/qom/object.c b/qom/object.c
>> index 351b88c..03e6f24 100644
>> --- a/qom/object.c
>> +++ b/qom/object.c
>> @@ -1017,7 +1017,7 @@ gchar *object_get_canonical_path(Object *obj)
>>      return newpath;
>>  }
>>  
>> -Object *object_resolve_path_component(Object *parent, gchar *part)
>> +Object *object_resolve_path_component(Object *parent, const gchar *part)
>>  {
>>      ObjectProperty *prop = object_property_find(parent, part, NULL);
>>      if (prop == NULL) {
> 
> Unrelated: do we really want to go along with glib's basic type typedef
> silliness?

Elsewhere I have adopted the exact GLib signature since typedefs can be
changed at any time. In particular the GCompareFunc using gconstpointer,
gint, etc. Not saying I find their GLib usage useful.

I admit I didn't review object_property_find(), which uses const char*.
So I wouldn't mind sending a v2 if non-g is preferred. Or Anthony or
Stefan could just edit the patch in my name before applying. :)

Andreas

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