utils: codegen: ipc: Generate templated constructor

Forcing the "non-pod" members to be initialized from `const T&` is not the
ideal solution because it disallows e.g. move constructors. So generate a
templated constructor, which members to be initialized more freely, e.g.
using move constructors.

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>

utils/codegen/ipc/generators/libcamera_templates/core_ipa_interface.h.tmpl

@@ -16,6 +16,8 @@
 
 {% if has_map %}#include <map>{% endif %}
 {% if has_string %}#include <string>{% endif %}
+#include <type_traits>
+#include <utility>
 {% if has_array %}#include <vector>{% endif %}
 
 #include <libcamera/controls.h>

utils/codegen/ipc/generators/libcamera_templates/definition_functions.tmpl

@@ -28,14 +28,21 @@ public:
 #ifndef __DOXYGEN__
 	{{struct.mojom_name}}() = default;
 
+	template<
+	{%- for field in struct.fields %}
+		typename T{{loop.index}} = {{field|name}},
+	{%- endfor %}
+	{%- for field in struct.fields %}
+		std::enable_if_t<std::is_convertible_v<T{{loop.index}}&&, {{field|name}}>> * = nullptr{{"," if not loop.last}}
+	{%- endfor %}
+	>
 	{{struct.mojom_name}}(
 {%- for field in struct.fields -%}
-{{"const " if not field|is_pod}}{{field|name}} {{"&" if not field|is_pod}}_{{field.mojom_name}}{{", " if not loop.last}}
+		T{{loop.index}} &&_{{field.mojom_name}}{{ ", " if not loop.last }}
 {%- endfor -%}
 )
-		:
-{%- for field in struct.fields -%}
-{{" " if loop.first}}{{field.mojom_name}}(_{{field.mojom_name}}){{", " if not loop.last}}
+{%- for field in struct.fields %}
+		{{": " if loop.first else ", "}}{{field.mojom_name}}(std::forward<T{{loop.index}}>(_{{field.mojom_name}}))
 {%- endfor %}
 	{
 	}

utils/codegen/ipc/generators/libcamera_templates/module_ipa_interface.h.tmpl

@@ -16,6 +16,8 @@
 
 {% if has_map %}#include <map>{% endif %}
 {% if has_string %}#include <string>{% endif %}
+#include <type_traits>
+#include <utility>
 {% if has_array %}#include <vector>{% endif %}
 
 #include <libcamera/base/flags.h>