[PATCH 7/9] qapi: Generalize enum member policy checking

[John Snow]

On Mon, Oct 25, 2021 at 1:26 AM Markus Armbruster <armbru at redhat.com> wrote:

> The code to check enumeration value policy can see special feature
> flag 'deprecated' in QEnumLookup member flags[value].  I want to make
> feature flag 'unstable' visible there as well, so I can add policy for
> it.
>
> Instead of extending flags[], replace it by @special_features (a
> bitset of QapiSpecialFeature), because that's how special features get
> passed around elsewhere.
>
> Signed-off-by: Markus Armbruster <armbru at redhat.com>
> ---
>  include/qapi/util.h    |  5 +----
>  qapi/qapi-visit-core.c |  3 ++-
>  scripts/qapi/types.py  | 22 ++++++++++++----------
>  3 files changed, 15 insertions(+), 15 deletions(-)
>
> diff --git a/include/qapi/util.h b/include/qapi/util.h
> index 7a8d5c7d72..0cc98db9f9 100644
> --- a/include/qapi/util.h
> +++ b/include/qapi/util.h
> @@ -15,12 +15,9 @@ typedef enum {
>      QAPI_DEPRECATED,
>  } QapiSpecialFeature;
>
> -/* QEnumLookup flags */
> -#define QAPI_ENUM_DEPRECATED 1
> -
>  typedef struct QEnumLookup {
>      const char *const *array;
> -    const unsigned char *const flags;
> +    const unsigned char *const special_features;
>      const int size;
>  } QEnumLookup;
>
> diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
> index b4a81f1757..5572d90efb 100644
> --- a/qapi/qapi-visit-core.c
> +++ b/qapi/qapi-visit-core.c
> @@ -407,7 +407,8 @@ static bool input_type_enum(Visitor *v, const char
> *name, int *obj,
>          return false;
>      }
>
> -    if (lookup->flags && (lookup->flags[value] & QAPI_ENUM_DEPRECATED)) {
> +    if (lookup->special_features
> +        && (lookup->special_features[value] & QAPI_DEPRECATED)) {
>          switch (v->compat_policy.deprecated_input) {
>          case COMPAT_POLICY_INPUT_ACCEPT:
>              break;
> diff --git a/scripts/qapi/types.py b/scripts/qapi/types.py
> index ab2441adc9..3013329c24 100644
> --- a/scripts/qapi/types.py
> +++ b/scripts/qapi/types.py
> @@ -16,7 +16,7 @@
>  from typing import List, Optional
>
>  from .common import c_enum_const, c_name, mcgen
> -from .gen import QAPISchemaModularCVisitor, ifcontext
> +from .gen import QAPISchemaModularCVisitor, gen_special_features,
> ifcontext
>  from .schema import (
>      QAPISchema,
>      QAPISchemaEnumMember,
> @@ -39,7 +39,7 @@ def gen_enum_lookup(name: str,
>                      members: List[QAPISchemaEnumMember],
>                      prefix: Optional[str] = None) -> str:
>      max_index = c_enum_const(name, '_MAX', prefix)
> -    flags = ''
> +    feats = ''
>      ret = mcgen('''
>
>  const QEnumLookup %(c_name)s_lookup = {
> @@ -54,19 +54,21 @@ def gen_enum_lookup(name: str,
>  ''',
>                       index=index, name=memb.name)
>          ret += memb.ifcond.gen_endif()
> -        if 'deprecated' in (f.name for f in memb.features):
> -            flags += mcgen('''
> -        [%(index)s] = QAPI_ENUM_DEPRECATED,
> -''',
> -                           index=index)
>
> -    if flags:
> +        special_features = gen_special_features(memb.features)
> +        if special_features != '0':
>

Though, I have to admit the common reoccurrence of this pattern suggests to
me that gen_special_features really ought to be returning something false-y
in these cases. Something about testing for the empty case with something
that represents, but isn't empty, gives me a brief pause.

Not willing to wage war over it.


> +            feats += mcgen('''
> +        [%(index)s] = %(special_features)s,
> +''',
> +                           index=index, special_features=special_features)
> +
> +    if feats:
>          ret += mcgen('''
>      },
> -    .flags = (const unsigned char[%(max_index)s]) {
> +    .special_features = (const unsigned char[%(max_index)s]) {
>  ''',
>                       max_index=max_index)
> -        ret += flags
> +        ret += feats
>
>      ret += mcgen('''
>      },
> --
> 2.31.1
>
>
Python bits: Acked-by: John Snow <jsnow at redhat.com>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/libvir-list/attachments/20211025/3aaf1815/attachment-0001.htm>