[libcamera-devel] [PATCH v5 8/9] utils: ipc: Allow the skipHeader attribute on enums

[Jacopo Mondi]

Hi Paul

On Tue, Oct 11, 2022 at 07:58:58PM +0900, Paul Elder via libcamera-devel wrote:
> Currently, enums that are passed between pipeline handlers and their IPA
> must be defined in a mojom file. However, there is a use case for
> enum/flags to be defined in a C++ header, such that the enum can be used
> in a component other than the pipeline handler and its IPA.
>
> To support this, add support for the skipHeader attribute for enums.
> Like structs, it is only allowed in core.mojom.
>
> Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
>
> ---
> New in v5
> ---
>  include/libcamera/ipa/core.mojom                              | 4 +++-
>  include/libcamera/ipa/ipa_interface.h                         | 4 ++--
>  .../generators/libcamera_templates/core_ipa_interface.h.tmpl  | 2 +-
>  utils/ipc/generators/mojom_libcamera_generator.py             | 2 +-
>  4 files changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/include/libcamera/ipa/core.mojom b/include/libcamera/ipa/core.mojom
> index ef28ff2d..1ff674b0 100644
> --- a/include/libcamera/ipa/core.mojom
> +++ b/include/libcamera/ipa/core.mojom
> @@ -14,7 +14,7 @@ module libcamera;
>   * - structs
>   *
>   * Attributes:
> - * - skipHeader - structs only, and only in core.mojom
> + * - skipHeader - allowed only for structs and enums in core.mojom
>   *   - Do not generate a C++ definition for the structure

s/structure/type ?

>   *   - Any type used in a mojom interface definition must have a corresponding
>   *     definition in a mojom file for the code generator to accept it, except

I guess we don't want [skipSerdes] for enums ? Or do we ?

> @@ -52,6 +52,8 @@ module libcamera;
>   *   then the type definition in the core.mojom file should have the
>   *   [skipHeader] attribute only
>   *   - A (de)serializer will be generated for the type
> + *   - enums that are defined in a libcamera C++ header also fall in this
> + *     category

Is this necessary, as we already claimed the attribute applies to
struct and enums ?

>   * - If a type definition has [skipHeader], then the header where the type is
>   *   defined must be included in ipa_interface.h
>   * - Types that are solely used as array/map members do not require a mojom
> diff --git a/include/libcamera/ipa/ipa_interface.h b/include/libcamera/ipa/ipa_interface.h
> index 8afcfe21..8884f0ed 100644
> --- a/include/libcamera/ipa/ipa_interface.h
> +++ b/include/libcamera/ipa/ipa_interface.h
> @@ -23,8 +23,8 @@
>  namespace libcamera {
>
>  /*
> - * Structs that are defined in core.mojom and have the skipHeader tag must be
> - * #included here.
> + * Structs and enums that are defined in core.mojom that have the skipHeader
> + * tag must be #included here.

I would take the occasion to re-phrase this:

    * The header file where symbols used in core.mojom are defined
    * must be #included here

If my understanding is correct

>   */
>
>  class IPAInterface
> diff --git a/utils/ipc/generators/libcamera_templates/core_ipa_interface.h.tmpl b/utils/ipc/generators/libcamera_templates/core_ipa_interface.h.tmpl
> index a565b59a..c60b99b8 100644
> --- a/utils/ipc/generators/libcamera_templates/core_ipa_interface.h.tmpl
> +++ b/utils/ipc/generators/libcamera_templates/core_ipa_interface.h.tmpl
> @@ -26,7 +26,7 @@ namespace libcamera {
>  static const {{const.kind|name}} {{const.mojom_name}} = {{const.value}};
>  {% endfor %}
>
> -{% for enum in enums %}
> +{% for enum in enums_gen_header %}
>  {{funcs.define_enum(enum)}}
>  {% endfor %}
>
> diff --git a/utils/ipc/generators/mojom_libcamera_generator.py b/utils/ipc/generators/mojom_libcamera_generator.py
> index 6c176aba..64987ccd 100644
> --- a/utils/ipc/generators/mojom_libcamera_generator.py
> +++ b/utils/ipc/generators/mojom_libcamera_generator.py
> @@ -483,7 +483,7 @@ class Generator(generator.Generator):
>      def _GetJinjaExportsForCore(self):
>          return {
>              'consts': self.module.constants,
> -            'enums': self.module.enums,
> +            'enums_gen_header': [x for x in self.module.enums if x.attributes is None or 'skipHeader' not in x.attributes],
>              'has_array': len([x for x in self.module.kinds.keys() if x[0] == 'a']) > 0,
>              'has_map': len([x for x in self.module.kinds.keys() if x[0] == 'm']) > 0,
>              'structs_gen_header': [x for x in self.module.structs if x.attributes is None or 'skipHeader' not in x.attributes],
> --
> 2.30.2
>