[RFC PATCH v1 7/8] libcamera: ipa_data_serializer: Add specialization for enums
Jacopo Mondi
jacopo.mondi at ideasonboard.com
Tue May 20 15:11:42 CEST 2025
Hi Barnabás
On Thu, May 15, 2025 at 02:00:11PM +0200, Barnabás Pőcze wrote:
> Instead of handling enums specially in the code generation templates,
> create a specialization of `IPADataSerializer` that handles enums.
>
> To stay compatible, encode every enum as a `uint32_t`, and also
> static_assert that the given enum type is smaller.
>
> Signed-off-by: Barnabás Pőcze <barnabas.pocze at ideasonboard.com>
> ---
> .../libcamera/internal/ipa_data_serializer.h | 48 ++++++++++++++++++-
> .../libcamera_templates/proxy_functions.tmpl | 17 +------
> .../libcamera_templates/serializer.tmpl | 14 ------
> 3 files changed, 48 insertions(+), 31 deletions(-)
>
> diff --git a/include/libcamera/internal/ipa_data_serializer.h b/include/libcamera/internal/ipa_data_serializer.h
> index b1fefba58..564f59e25 100644
> --- a/include/libcamera/internal/ipa_data_serializer.h
> +++ b/include/libcamera/internal/ipa_data_serializer.h
> @@ -61,7 +61,7 @@ T readPOD(std::vector<uint8_t> &vec, size_t pos)
>
> } /* namespace */
>
> -template<typename T>
> +template<typename T, typename = void>
It took me a bit of time to understand why, give the above
> class IPADataSerializer
> {
> public:
> @@ -344,6 +344,52 @@ public:
> }
> };
>
> +template<typename E>
> +class IPADataSerializer<E, std::enable_if_t<std::is_enum_v<E>>>
This could work for other E that are not enums, or in other words, I
was expecting that we need to have an overload for !std::is_enum<>
Later I realized that all other specializations here are for containers
like vector<E> map<K, E> and Flag<E>, and all other types will have a
generated specialization.
Do you know how many copies of this function will be generated by the
compiler ? One for each enum type specified in the interface file ?
Anyway, looks good to me
Reviewed-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>
> +{
> + using U = uint32_t;
> + static_assert(sizeof(E) <= sizeof(U));
> +
> +public:
> + static std::tuple<std::vector<uint8_t>, std::vector<SharedFD>>
> + serialize(const E &data, [[maybe_unused]] ControlSerializer *cs = nullptr)
> + {
> + std::vector<uint8_t> dataVec;
> + appendPOD<U>(dataVec, static_cast<U>(data));
> +
> + return { dataVec, {} };
> + }
> +
> + static E deserialize(std::vector<uint8_t> &data,
> + [[maybe_unused]] ControlSerializer *cs = nullptr)
> + {
> + return deserialize(data.cbegin(), data.cend());
> + }
> +
> + static E deserialize(std::vector<uint8_t>::const_iterator dataBegin,
> + std::vector<uint8_t>::const_iterator dataEnd,
> + [[maybe_unused]] ControlSerializer *cs = nullptr)
> + {
> + return static_cast<E>(readPOD<U>(dataBegin, 0, dataEnd));
> + }
> +
> + static E deserialize(std::vector<uint8_t> &data,
> + [[maybe_unused]] std::vector<SharedFD> &fds,
> + [[maybe_unused]] ControlSerializer *cs = nullptr)
> + {
> + return deserialize(data.cbegin(), data.cend());
> + }
> +
> + static E deserialize(std::vector<uint8_t>::const_iterator dataBegin,
> + std::vector<uint8_t>::const_iterator dataEnd,
> + [[maybe_unused]] std::vector<SharedFD>::const_iterator fdsBegin,
> + [[maybe_unused]] std::vector<SharedFD>::const_iterator fdsEnd,
> + [[maybe_unused]] ControlSerializer *cs = nullptr)
> + {
> + return deserialize(dataBegin, dataEnd);
> + }
> +};
> +
> #endif /* __DOXYGEN__ */
>
> } /* namespace libcamera */
> diff --git a/utils/codegen/ipc/generators/libcamera_templates/proxy_functions.tmpl b/utils/codegen/ipc/generators/libcamera_templates/proxy_functions.tmpl
> index 25476990e..01e2567ca 100644
> --- a/utils/codegen/ipc/generators/libcamera_templates/proxy_functions.tmpl
> +++ b/utils/codegen/ipc/generators/libcamera_templates/proxy_functions.tmpl
> @@ -52,9 +52,6 @@
> #}
> {%- macro serialize_call(params, buf, fds) %}
> {%- for param in params %}
> -{%- if param|is_enum %}
> - static_assert(sizeof({{param|name_full}}) <= 4);
> -{%- endif %}
> std::vector<uint8_t> {{param.mojom_name}}Buf;
> {%- if param|has_fd %}
> std::vector<SharedFD> {{param.mojom_name}}Fds;
> @@ -62,13 +59,7 @@
> {%- else %}
> std::tie({{param.mojom_name}}Buf, std::ignore) =
> {%- endif %}
> -{%- if param|is_flags %}
> IPADataSerializer<{{param|name_full}}>::serialize({{param.mojom_name}}
> -{%- elif param|is_enum %}
> - IPADataSerializer<uint32_t>::serialize(static_cast<uint32_t>({{param.mojom_name}})
> -{%- else %}
> - IPADataSerializer<{{param|name}}>::serialize({{param.mojom_name}}
> -{% endif -%}
> {{- ", &controlSerializer_" if param|needs_control_serializer -}}
> );
> {%- endfor %}
> @@ -107,13 +98,7 @@
> #}
> {%- macro deserialize_param(param, pointer, loop, buf, fds, iter, data_size) -%}
> {{"*" if pointer}}{{param.mojom_name}} =
> -{%- if param|is_flags %}
> IPADataSerializer<{{param|name_full}}>::deserialize(
> -{%- elif param|is_enum %}
> -static_cast<{{param|name_full}}>(IPADataSerializer<uint32_t>::deserialize(
> -{%- else %}
> -IPADataSerializer<{{param|name}}>::deserialize(
> -{%- endif %}
> {{buf}}{{- ".cbegin()" if not iter}} + {{param.mojom_name}}Start,
> {%- if loop.last and not iter %}
> {{buf}}.cend()
> @@ -137,7 +122,7 @@ IPADataSerializer<{{param|name}}>::deserialize(
> {%- if param|needs_control_serializer %}
> &controlSerializer_
> {%- endif -%}
> -){{")" if param|is_enum and not param|is_flags}};
> +);
> {%- endmacro -%}
>
>
> diff --git a/utils/codegen/ipc/generators/libcamera_templates/serializer.tmpl b/utils/codegen/ipc/generators/libcamera_templates/serializer.tmpl
> index d07836cc1..e316dd88a 100644
> --- a/utils/codegen/ipc/generators/libcamera_templates/serializer.tmpl
> +++ b/utils/codegen/ipc/generators/libcamera_templates/serializer.tmpl
> @@ -32,15 +32,7 @@
> {%- if field|is_pod or field|is_enum %}
> std::vector<uint8_t> {{field.mojom_name}};
> std::tie({{field.mojom_name}}, std::ignore) =
> - {%- if field|is_pod %}
> - IPADataSerializer<{{field|name}}>::serialize(data.{{field.mojom_name}});
> - {%- elif field|is_flags %}
> IPADataSerializer<{{field|name_full}}>::serialize(data.{{field.mojom_name}});
> - {%- elif field|is_enum_scoped %}
> - IPADataSerializer<uint{{field|bit_width}}_t>::serialize(static_cast<uint{{field|bit_width}}_t>(data.{{field.mojom_name}}));
> - {%- elif field|is_enum %}
> - IPADataSerializer<uint{{field|bit_width}}_t>::serialize(data.{{field.mojom_name}});
> - {%- endif %}
> retData.insert(retData.end(), {{field.mojom_name}}.begin(), {{field.mojom_name}}.end());
> {%- elif field|is_fd %}
> std::vector<uint8_t> {{field.mojom_name}};
> @@ -98,13 +90,7 @@
> {% if field|is_pod or field|is_enum %}
> {%- set field_size = (field|bit_width|int / 8)|int %}
> {{- check_data_size(field_size, 'dataSize', field.mojom_name, 'data')}}
> - {%- if field|is_pod %}
> - ret.{{field.mojom_name}} = IPADataSerializer<{{field|name}}>::deserialize(m, m + {{field_size}});
> - {%- elif field|is_flags %}
> ret.{{field.mojom_name}} = IPADataSerializer<{{field|name_full}}>::deserialize(m, m + {{field_size}});
> - {%- else %}
> - ret.{{field.mojom_name}} = static_cast<{{field|name_full}}>(IPADataSerializer<uint{{field|bit_width}}_t>::deserialize(m, m + {{field_size}}));
> - {%- endif %}
> {%- if not loop.last %}
> m += {{field_size}};
> dataSize -= {{field_size}};
> --
> 2.49.0
>
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