opencv_binding_generator/writer/rust_native/

smart_ptr.rs

use std::borrow::Cow;
use std::collections::HashMap;
use std::sync::LazyLock;

use super::class::ClassExt;
use super::element::RustElement;
use super::type_ref::TypeRefExt;
use super::RustNativeGeneratedElement;
use crate::class::ClassDesc;
use crate::field::{Field, FieldDesc};
use crate::func::{FuncCppBody, FuncDesc, FuncKind, ReturnKind};
use crate::smart_ptr::SmartPtrDesc;
use crate::type_ref::{Constness, CppNameStyle, FishStyle, NameStyle, TypeRef, TypeRefKind};
use crate::writer::rust_native::class::rust_generate_debug_fields;
use crate::{Class, CompiledInterpolation, Element, Func, IteratorExt, SmartPtr, StrExt, StringExt, SupportedModule};

impl RustElement for SmartPtr<'_, '_> {
	fn rust_module(&self) -> SupportedModule {
		self.pointee().rust_module()
	}

	// fixme, we shouldn't override the rust_module_reference and rely on rust_module to provide the correct module
	fn rust_module_reference(&self) -> Cow<'_, str> {
		"core".into()
	}

	fn rust_name(&self, style: NameStyle) -> Cow<'_, str> {
		let decl_name = self.rust_leafname(style.turbo_fish_style());
		match style {
			NameStyle::Declaration => decl_name,
			NameStyle::Reference(_) => {
				let mut out = self.rust_module_reference().into_owned();
				out.extend_sep("::", &decl_name);
				out.into()
			}
		}
	}

	fn rust_leafname(&self, fish_style: FishStyle) -> Cow<'_, str> {
		format!(
			"Ptr{fish}<{typ}>",
			fish = fish_style.rust_qual(),
			typ = self.pointee().rust_name(NameStyle::ref_()),
		)
		.into()
	}
}

impl RustNativeGeneratedElement for SmartPtr<'_, '_> {
	fn element_safe_id(&self) -> String {
		format!("{}-{}", self.rust_module().opencv_name(), self.rust_localalias())
	}

	fn gen_rust(&self, _opencv_version: &str) -> String {
		static TPL: LazyLock<CompiledInterpolation> =
			LazyLock::new(|| include_str!("tpl/smart_ptr/rust.tpl.rs").compile_interpolation());

		static TRAIT_RAW_TPL: LazyLock<CompiledInterpolation> =
			LazyLock::new(|| include_str!("tpl/smart_ptr/trait_raw.tpl.rs").compile_interpolation());

		static BASE_CAST_TPL: LazyLock<CompiledInterpolation> =
			LazyLock::new(|| include_str!("tpl/smart_ptr/base_cast.tpl.rs").compile_interpolation());

		static IMPL_DEBUG_TPL: LazyLock<CompiledInterpolation> =
			LazyLock::new(|| include_str!("tpl/smart_ptr/impl_debug.rs").compile_interpolation());

		static CTOR_TPL: LazyLock<CompiledInterpolation> =
			LazyLock::new(|| include_str!("tpl/smart_ptr/ctor.tpl.rs").compile_interpolation());

		let rust_localalias = self.rust_localalias();
		let rust_full = self.rust_name(NameStyle::ref_());
		let pointee_type = self.pointee();
		let pointee_kind = pointee_type.kind();
		let inner_rust_full = pointee_type.rust_name(NameStyle::ref_());
		let type_ref = self.type_ref();
		let smartptr_class = smartptr_class(&type_ref);

		let extern_get_inner_ptr = method_get_inner_ptr(
			smartptr_class.clone(),
			pointee_type.as_ref().clone().with_inherent_constness(Constness::Const),
		)
		.identifier();
		let extern_get_inner_ptr_mut = method_get_inner_ptr(
			smartptr_class.clone(),
			pointee_type.as_ref().clone().with_inherent_constness(Constness::Mut),
		)
		.identifier();

		let mut impls = String::with_capacity(1024);
		if let Some(cls) = pointee_kind.as_class().filter(|cls| cls.kind().is_trait()) {
			TRAIT_RAW_TPL.interpolate_into(
				&mut impls,
				&HashMap::from([
					("rust_full", rust_full.as_ref()),
					("base_rust_as_raw_const", &cls.rust_as_raw_name(Constness::Const)),
					("base_rust_as_raw_mut", &cls.rust_as_raw_name(Constness::Mut)),
					("base_rust_full_mut", &cls.rust_trait_name(NameStyle::ref_(), Constness::Mut)),
					(
						"base_rust_full_const",
						&cls.rust_trait_name(NameStyle::ref_(), Constness::Const),
					),
				]),
			);
			let mut debug_fields = rust_generate_debug_fields(
				cls.field_methods(&cls.fields(|f| f.exclude_kind().is_included()), Some(Constness::Const)),
			);
			for base in all_bases(&cls) {
				let base_rust_local = base.rust_name(NameStyle::decl());
				TRAIT_RAW_TPL.interpolate_into(
					&mut impls,
					&HashMap::from([
						("rust_full", rust_full.as_ref()),
						("base_rust_as_raw_const", &base.rust_as_raw_name(Constness::Const)),
						("base_rust_as_raw_mut", &base.rust_as_raw_name(Constness::Mut)),
						("base_rust_full_mut", &base.rust_trait_name(NameStyle::ref_(), Constness::Mut)),
						(
							"base_rust_full_const",
							&base.rust_trait_name(NameStyle::ref_(), Constness::Const),
						),
					]),
				);

				let extern_cast_to_base = method_cast_to_base(smartptr_class.clone(), base.type_ref(), &base_rust_local).identifier();
				BASE_CAST_TPL.interpolate_into(
					&mut impls,
					&HashMap::from([
						("rust_full", rust_full.as_ref()),
						("base_rust_full_ref", &base.rust_name(NameStyle::ref_())),
						("extern_cast_to_base", &extern_cast_to_base),
					]),
				);
				let base_fields = base.fields(|f| f.exclude_kind().is_included());
				let base_field_const_methods = base.field_methods(&base_fields, Some(Constness::Const));
				debug_fields.push_str(&rust_generate_debug_fields(base_field_const_methods));
			}
			IMPL_DEBUG_TPL.interpolate_into(
				&mut impls,
				&HashMap::from([
					("rust_full", rust_full.as_ref()),
					("rust_localalias", &rust_localalias),
					("debug_fields", &debug_fields),
				]),
			);
		};

		let rust_as_raw_const = type_ref.rust_as_raw_name(Constness::Const);
		let rust_as_raw_mut = type_ref.rust_as_raw_name(Constness::Mut);

		let ctor = if gen_ctor(&pointee_kind) {
			let extern_new = method_new(smartptr_class.clone(), type_ref.clone(), pointee_type.as_ref().clone()).identifier();
			CTOR_TPL.interpolate(&HashMap::from([
				("inner_rust_full", inner_rust_full.as_ref()),
				("extern_new", &extern_new),
			]))
		} else {
			"".to_string()
		};

		let extern_new_null = method_new_null(smartptr_class.clone(), type_ref).identifier();
		let extern_delete = FuncDesc::method_delete(smartptr_class).identifier();
		TPL.interpolate(&HashMap::from([
			("rust_localalias", rust_localalias.as_ref()),
			("rust_as_raw_const", &rust_as_raw_const),
			("rust_as_raw_mut", &rust_as_raw_mut),
			("rust_full", &rust_full),
			("inner_rust_full", &inner_rust_full),
			("extern_new_null", &extern_new_null),
			("extern_delete", &extern_delete),
			("extern_get_inner_ptr", &extern_get_inner_ptr),
			("extern_get_inner_ptr_mut", &extern_get_inner_ptr_mut),
			("ctor", &ctor),
			("impls", &impls),
		]))
	}

	fn gen_rust_externs(&self) -> String {
		extern_functions(self).iter().map(Func::gen_rust_externs).join("")
	}

	fn gen_cpp(&self) -> String {
		static TPL: LazyLock<CompiledInterpolation> =
			LazyLock::new(|| include_str!("tpl/smart_ptr/cpp.tpl.cpp").compile_interpolation());

		TPL.interpolate(&[("methods", extern_functions(self).iter().map(Func::gen_cpp).join(""))].into())
	}
}

fn extern_functions<'tu, 'ge>(ptr: &SmartPtr<'tu, 'ge>) -> Vec<Func<'tu, 'ge>> {
	let type_ref = ptr.type_ref();
	let pointee_type = ptr.pointee();
	let pointee_kind = pointee_type.kind();
	let smartptr_class = smartptr_class(&type_ref);

	let mut out = Vec::with_capacity(6);
	out.push(method_get_inner_ptr(
		smartptr_class.clone(),
		pointee_type.as_ref().clone().with_inherent_constness(Constness::Const),
	));
	out.push(method_get_inner_ptr(
		smartptr_class.clone(),
		pointee_type.as_ref().clone().with_inherent_constness(Constness::Mut),
	));
	out.push(method_new_null(smartptr_class.clone(), type_ref.clone()));
	out.push(FuncDesc::method_delete(smartptr_class.clone()));
	if let Some(cls) = pointee_kind.as_class().filter(|cls| cls.kind().is_trait()) {
		for base in all_bases(&cls) {
			out.push(method_cast_to_base(
				smartptr_class.clone(),
				base.type_ref(),
				&base.rust_name(NameStyle::decl()),
			));
		}
	}
	if gen_ctor(&pointee_kind) {
		out.push(method_new(smartptr_class, type_ref, pointee_type.into_owned()));
	}
	out
}

fn gen_ctor(pointee_kind: &TypeRefKind) -> bool {
	match pointee_kind.canonical().as_ref() {
		TypeRefKind::Primitive(_, _) => true,
		TypeRefKind::Class(cls) => !cls.is_abstract(),
		_ => false,
	}
}

fn all_bases<'tu, 'ge>(cls: &Class<'tu, 'ge>) -> Vec<Class<'tu, 'ge>> {
	let mut out = cls
		.all_bases()
		.into_iter()
		.filter(|b| b.exclude_kind().is_included())
		.collect::<Vec<_>>();
	out.sort_unstable_by(|left, right| {
		left
			.cpp_name(CppNameStyle::Reference)
			.cmp(&right.cpp_name(CppNameStyle::Reference))
	});
	out
}

pub trait SmartPtrExt {
	fn rust_localalias(&self) -> Cow<'_, str>;
}

impl SmartPtrExt for SmartPtr<'_, '_> {
	fn rust_localalias(&self) -> Cow<'_, str> {
		/*
		let pointee = self.pointee();
		let pointee_alias = pointee.rust_safe_id(true);
		let pointee_alias = if let Some(rem) = pointee_alias.strip_prefix("const_") {
			format!("Const{rem}").into()
		} else {
			pointee_alias
		};
		format!("PtrOf{pointee_alias}").into()
		*/
		// fixme: Not adding const here in rust_safe_id() leads to some smart pointers losing the const qualifier on the internal
		// type (e.g. cv::Ptr<const cv::optflow::PCAPrior>). If we add it (see commented code above) it leads to problems with casting
		// because casting doesn't take constness into account. This might not be a problem per se (e.g. if we own Ptr<PCAPrior> there is
		// no problem to pass it as Ptr<const PCAPrior>), otherwise fix it so that it works with add_const = true in rust_safe_id().
		format!("PtrOf{typ}", typ = self.pointee().rust_safe_id(false)).into()
	}
}

fn smartptr_class<'tu, 'ge>(smart_ptr_type_ref: &TypeRef<'tu, 'ge>) -> Class<'tu, 'ge> {
	Class::new_desc(ClassDesc::boxed(
		smart_ptr_type_ref.cpp_name(CppNameStyle::Reference),
		SupportedModule::Core,
	))
}

fn method_new<'tu, 'ge>(
	smartptr_class: Class<'tu, 'ge>,
	smartptr_type_ref: TypeRef<'tu, 'ge>,
	pointee_type: TypeRef<'tu, 'ge>,
) -> Func<'tu, 'ge> {
	let pointee_kind = pointee_type.kind();
	let val = if pointee_kind.is_copy(pointee_type.type_hint()) {
		if pointee_kind.as_class().is_some_and(|cls| cls.kind().is_simple()) {
			panic!("Ptr with simple class is not supported");
		} else {
			format!("new {typ}(val)", typ = pointee_type.cpp_name(CppNameStyle::Reference)).into()
		}
	} else {
		Cow::Borrowed("val")
	};
	Func::new_desc(
		FuncDesc::new(
			FuncKind::Constructor(smartptr_class),
			Constness::Const,
			ReturnKind::InfallibleNaked,
			"new",
			SupportedModule::Core,
			[Field::new_desc(FieldDesc::new("val", pointee_type))],
			smartptr_type_ref,
		)
		.cpp_body(FuncCppBody::ManualCallReturn(
			format!("return new {{{{ret_type}}}}({val});").into(),
		)),
	)
}

fn method_new_null<'tu, 'ge>(smartptr_class: Class<'tu, 'ge>, smartptr_type_ref: TypeRef<'tu, 'ge>) -> Func<'tu, 'ge> {
	Func::new_desc(
		FuncDesc::new(
			FuncKind::Constructor(smartptr_class),
			Constness::Const,
			ReturnKind::InfallibleNaked,
			"new_null",
			SupportedModule::Core,
			[],
			smartptr_type_ref,
		)
		.cpp_body(FuncCppBody::ManualCallReturn("return new {{ret_type}}();".into())),
	)
}

fn method_cast_to_base<'tu, 'ge>(
	smartptr_class: Class<'tu, 'ge>,
	base_type_ref: TypeRef<'tu, 'ge>,
	base_rust_local: &str,
) -> Func<'tu, 'ge> {
	let cpp_body = FuncCppBody::ManualCallReturn(
		format!(
			"return new {{{{ret_type}}}}(instance->dynamicCast<{base_type}>());",
			base_type = base_type_ref.cpp_name(CppNameStyle::Reference)
		)
		.into(),
	);
	Func::new_desc(
		FuncDesc::new(
			FuncKind::InstanceMethod(smartptr_class),
			Constness::Mut,
			ReturnKind::InfallibleNaked,
			format!("to_PtrOf{base_rust_local}"),
			SupportedModule::Core,
			[],
			TypeRef::new_smartptr(SmartPtr::new_desc(SmartPtrDesc::new(base_type_ref))),
		)
		.cpp_body(cpp_body),
	)
}

fn method_get_inner_ptr<'tu, 'ge>(smartptr_class: Class<'tu, 'ge>, pointee_type: TypeRef<'tu, 'ge>) -> Func<'tu, 'ge> {
	// if the pointee type is actually const make sure to also generate a const function, needed for
	// Ptr<const cv::optflow::PCAPrior*>
	let constness = pointee_type.constness();
	let return_type_ref = if pointee_type.kind().extern_pass_kind().is_by_ptr() {
		pointee_type
	} else {
		TypeRef::new_pointer(pointee_type)
	};
	Func::new_desc(
		FuncDesc::new(
			FuncKind::InstanceMethod(smartptr_class),
			constness,
			ReturnKind::InfallibleNaked,
			format!("getInnerPtr{}", constness.rust_name_qual()),
			SupportedModule::Core,
			[],
			return_type_ref,
		)
		.cpp_body(FuncCppBody::ManualCallReturn("return instance->get();".into())),
	)
}