utils: ipc: Do not define variables in signal handler up front

Defining the variables at the beginning of the function forces the types
to be default constructible, which may not be desirable; furthermore, it
also forces the move/copy assignment operator to be used when the
deserialized value is retrieved.

Having `T val = f()` has the advantage of benefitting from potential RVO
as well as not requiring `T` to be default constructible, so generate
code in that form by calling `deserialize_call()` with `declare=true`.

Signed-off-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 1 insertions, 4 deletions

diff --git a/utils/codegen/ipc/generators/libcamera_templates/module_ipa_proxy.cpp.tmpl b/utils/codegen/ipc/generators/libcamera_templates/module_ipa_proxy.cpp.tmpl
index ce3cc5ab..07165821 100644
--- a/utils/codegen/ipc/generators/libcamera_templates/module_ipa_proxy.cpp.tmpl
+++ b/utils/codegen/ipc/generators/libcamera_templates/module_ipa_proxy.cpp.tmpl
@@ -239,10 +239,7 @@ void {{proxy_name}}::{{method.mojom_name}}IPC(
 	[[maybe_unused]] size_t dataSize,
 	[[maybe_unused]] const std::vector<SharedFD> &fds)
 {
-{%- for param in method.parameters %}
-	{{param|name}} {{param.mojom_name}};
-{%- endfor %}
-{{proxy_funcs.deserialize_call(method.parameters, 'data', 'fds', false, false, true, 'dataSize')}}
+{{proxy_funcs.deserialize_call(method.parameters, 'data', 'fds', false, true, true, 'dataSize')}}
 	{{method.mojom_name}}.emit({{method.parameters|params_comma_sep}});
 }
 {% endfor %}