Re: [Qemu-devel] [PATCH v2 2/3] qemu-help: Sort devices by logical functionality

[Marcel Apfelbaum]

On Mon, 2013-07-29 at 11:04 +0300, Michael S. Tsirkin wrote:
> On Mon, Jul 29, 2013 at 10:07:34AM +0300, Marcel Apfelbaum wrote:
> > Categorize devices that appear as output to "-device ?" command
> > by logical functionality. Sort the devices by logical categories
> > before showing them to user.
> > 
> > The sort is done by functionality rather than alphabetical.
> > 
> > Signed-off-by: Marcel Apfelbaum <address@hidden>
> > ---
> > Changes from v1:
> > Addressed Michael Tsirkin review:
> > Used bitmap operations on categories
> > Moved category names into the header file
> > 
> >  include/hw/qdev-core.h | 33 +++++++++++++++++++++++++++++++++
> >  qdev-monitor.c         | 50 
> > ++++++++++++++++++++++++++++++++++++++++++++++----
> >  2 files changed, 79 insertions(+), 4 deletions(-)
> > 
> > diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
> > index e8b89b1..80b06ac 100644
> > --- a/include/hw/qdev-core.h
> > +++ b/include/hw/qdev-core.h
> > @@ -18,6 +18,38 @@ enum {
> >  #define DEVICE_CLASS(klass) OBJECT_CLASS_CHECK(DeviceClass, (klass), 
> > TYPE_DEVICE)
> >  #define DEVICE_GET_CLASS(obj) OBJECT_GET_CLASS(DeviceClass, (obj), 
> > TYPE_DEVICE)
> >  
> > +typedef enum DeviceCategory {
> > +    DEVICE_CATEGORY_ASSEMBLY,
> > +    DEVICE_CATEGORY_MANAGEMENT,
> > +    DEVICE_CATEGORY_STORAGE,
> > +    DEVICE_CATEGORY_NETWORK,
> > +    DEVICE_CATEGORY_INPUT,
> > +    DEVICE_CATEGORY_DISPLAY,
> > +    DEVICE_CATEGORY_SOUND,
> > +    DEVICE_CATEGORY_MISC,
> > +    DEVICE_CATEGORY_MAX
> > +} DeviceCategory;
> > +
> > +static inline const char *qdev_category_get_name(DeviceCategory category)
> > +{
> > +    /* Category names corresponding to DeviceCategory values
> > +     * The array elements must be in the same order as they
> > +     * appear in DeviceCategory enum.
> > +     */
> 
> I would simply do:
>      static const char *category_names[DEVICE_CATEGORY_MAX] = {
>          [DEVICE_CATEGORY_ASSEMBLY] = "Assembly",
>          [DEVICE_CATEGORY_MANAGEMENT] = "Management",
>          [DEVICE_CATEGORY_STORAGE] = "Storage",
>          [DEVICE_CATEGORY_NETWORK] = "Network",
>          [DEVICE_CATEGORY_INPUT] = "Input",
>          [DEVICE_CATEGORY_DISPLAY] = "Display",
>          [DEVICE_CATEGORY_SOUND] = "Sound",
>          [DEVICE_CATEGORY_MISC] = "Misc",
>      };
> 
> and drop the requirement to use same order.
OK
> 
> > +    static const char *category_names[] = {
> > +        "Assembly",
> > +        "Management",
> > +        "Storage",
> > +        "Network",
> > +        "Input",
> > +        "Display",
> > +        "Sound",
> > +        "Misc",
> > +    };
> 
> 
> > +
> > +    return category_names[category];
> > +}
> > +
> >  typedef int (*qdev_initfn)(DeviceState *dev);
> >  typedef int (*qdev_event)(DeviceState *dev);
> >  typedef void (*qdev_resetfn)(DeviceState *dev);
> > @@ -81,6 +113,7 @@ typedef struct DeviceClass {
> >      ObjectClass parent_class;
> >      /*< public >*/
> >  
> > +    DECLARE_BITMAP(categories, 20);
> 
> Why 20? Not DEVICE_CATEGORY_MAX ?
OK
> 
> 
> >      const char *fw_name;
> >      const char *desc;
> >      Property *props;
> > diff --git a/qdev-monitor.c b/qdev-monitor.c
> > index e54dbc2..c3a3550 100644
> > --- a/qdev-monitor.c
> > +++ b/qdev-monitor.c
> > @@ -75,14 +75,21 @@ static bool qdev_class_has_alias(DeviceClass *dc)
> >      return (qdev_class_get_alias(dc) != NULL);
> >  }
> >  
> > +typedef struct PrintDevInfoData {
> > +    bool show_no_user;
> > +    DeviceCategory category;
> > +} PrintDevInfoData ;
> > +
> >  static void qdev_print_devinfo(ObjectClass *klass, void *opaque)
> >  {
> >      DeviceClass *dc;
> > -    bool *show_no_user = opaque;
> > +    PrintDevInfoData *data = opaque;
> 
> So all callers of qdev_print_devinfo would have to be updated,
> but you only updated one caller.
> Lack of type checking here is nasty. It's required
> by the object_class_foreach but you are not using that
> anymore.
> 
> So please refactor this function: e.g.
> qdev_print_devinfo which gets void *,
> and qdev_print_class_devinfo which gets show_no_user and category.
> In fact, this way there won't be need for use of void *
> at all.
OK
> 
> 
> > +    DeviceCategory category;
> >  
> > +    category = data ? data->category : DEVICE_CATEGORY_MAX;
> >      dc = (DeviceClass *)object_class_dynamic_cast(klass, TYPE_DEVICE);
> >  
> > -    if (!dc || (show_no_user && !*show_no_user && dc->no_user)) {
> > +    if (!dc || (data && !data->show_no_user && dc->no_user)) {
> >          return;
> >      }
> >  
> > @@ -93,6 +100,18 @@ static void qdev_print_devinfo(ObjectClass *klass, void 
> > *opaque)
> >      if (qdev_class_has_alias(dc)) {
> >          error_printf(", alias \"%s\"", qdev_class_get_alias(dc));
> >      }
> > +    if (dc->categories) {
> 
> Is this sometimes unset? Some devices don't have a category?
All devices shall have a category
> 
> > +        if (test_bit(category, dc->categories)) {
> > +            error_printf(", category \"%s\"", 
> > qdev_category_get_name(category));
> > +        } else {
> > +            error_printf(", categories");
> > +            for (category = 0; category < DEVICE_CATEGORY_MAX; ++category) 
> > {
> > +                if (test_bit(category, dc->categories)) {
> > +                    error_printf(" \"%s\"", 
> > qdev_category_get_name(category));
> > +                }
> > +            }
> 
> Confused. Why different output format?
> Maybe add a comment with explanation.
> Also, testing DEVICE_CATEGORY_MAX will cause out of bounds
> access on bitmap - you want to special-case it
> explicitly.
> 
In RFC patches was possible to print a device that belonged
to a specific category, or print out all its categories.
In this series it can be done by passing DEVICE_CATEGORY_MAX

> Also, this overrides category parameter so if one tries to
> use it below one gets DEVICE_CATEGORY_MAX.
> Better use a different local variable for the loop.
OK
> 
> > +        }
> > +    }
> >      if (dc->desc) {
> >          error_printf(", desc \"%s\"", dc->desc);
> >      }
> > @@ -139,6 +158,23 @@ static const char *find_typename_by_alias(const char 
> > *alias)
> >      return NULL;
> >  }
> >  
> > +static GSList *qdev_get_devices_by_category(DeviceCategory category)
> > +{
> > +    DeviceClass *dc;
> > +    GSList *list, *curr, *ret_list = NULL;
> > +
> > +    list = object_class_get_list(TYPE_DEVICE, false);
> > +    for (curr = list; curr; curr = g_slist_next(curr)) {
> > +        dc = (DeviceClass *)object_class_dynamic_cast(curr->data, 
> > TYPE_DEVICE);
> > +        if (test_bit(category, dc->categories)) {
> > +            ret_list = g_slist_append(ret_list, dc);
> 
> So you build list here, then immediately scan it in
> the same order and free it.
> Wouldn't it be easier to just call qdev_print_devinfo here
> directly?
> 
> 
> > +        }
> > +    }
> > +    g_slist_free(list);
> > +
> > +    return ret_list;
> > +}
> > +
> >  int qdev_device_help(QemuOpts *opts)
> >  {
> >      const char *driver;
> > @@ -147,8 +183,14 @@ int qdev_device_help(QemuOpts *opts)
> >  
> >      driver = qemu_opt_get(opts, "driver");
> >      if (driver && is_help_option(driver)) {
> > -        bool show_no_user = false;
> > -        object_class_foreach(qdev_print_devinfo, TYPE_DEVICE, false, 
> > &show_no_user);
> > +        DeviceCategory category;
> > +        for (category = 0; category < DEVICE_CATEGORY_MAX; ++category) {
> > +            PrintDevInfoData data = { false, category };
> > +            GSList *list = qdev_get_devices_by_category(category);
> > +            g_slist_foreach(list, (GFunc)qdev_print_devinfo, &data);
> 
> This cast should be avoided. If function signatures do not match,
> you really don't want to work around it like this.
> Refactor code please.
OK
> 
> 
> > +            g_slist_free(list);
> > +        }
> > +
> >          return 1;
> >      }
> >  
> > -- 
> > 1.8.3.1