Add support for registering foreign methods that return foreign objects

Still a bit work in progress but functioning

examples/calendar/main.cpp

@@ -123,7 +123,7 @@ int main() {
 	vm.callback_manager().add_callback(true, "calendar", "Calendar", "today()", &Calendar::today)
 		.add_callback(false, "calendar", "Calendar", "add_appointment(_)", wren::make_method_bindable<&Calendar::add_appointment>())
 		.add_callback(false, "calendar", "Calendar", "appointment_count()", wren::make_method_bindable<&Calendar::appointment_count>());
-	vm.class_manager().add_class_maker("calendar", "Calendar", &wren::make_foreign_class<Calendar>);
+	vm.class_manager().add_class_maker("calendar", "Calendar", wren::make_foreign_class<Calendar>);
 
 	vm.interpret("main", g_test_script);
 

examples/math_vector/main.cpp

@@ -112,7 +112,7 @@ int main() {
 		.add_callback(false, "math_vector", "MathVector", "z", make_method_bindable<&Vector<double>::z>());
 
 	vm.class_manager()
-		.add_class_maker("math_vector", "MathVector", &make_foreign_class<Vector<double>,
+		.add_class_maker("math_vector", "MathVector", make_foreign_class<Vector<double>,
 			double, //single value constructor
 			std::tuple<double, double, double>, //x,y,z constructor
 			std::tuple<> //default constructor

include/wrenpp/class_manager.hpp

@@ -19,10 +19,13 @@
 
 #include "detail/wren_types.hpp"
 #include "detail/strings_in_vector.hpp"
+#include "detail/construct_foreign_class.hpp"
+#include "detail/wren_class_name_from_type.hpp"
 #include <unordered_map>
 #include <string>
 #include <type_traits>
 #include <functional>
+#include <utility>
 
 namespace wren {
 	namespace detail {
@@ -47,6 +50,7 @@ namespace wren {
 
 			std::string_view module_name() const { return this->as_string_view<0>(); }
 			std::string_view class_name() const { return this->as_string_view<1>(); }
+			operator ModuleAndName() const;
 
 			using StringsInVector<2>::operator<;
 			bool operator== (const ClassNameOwning& other) const;
@@ -58,6 +62,9 @@ namespace wren {
 			TempClassName (const ClassNameOwning& model);
 			bool operator== (const TempClassName& other) const;
 
+			std::string_view module_name() const { return m_module_name; }
+			std::string_view class_name() const { return m_class_name; }
+
 		private:
 			std::string_view m_module_name, m_class_name;
 		};
@@ -71,19 +78,73 @@ namespace wren {
 			using is_transparent = std::true_type;
 			std::size_t operator()(TempClassName value) const;
 		};
+
+		template <typename F>
+		struct CppClassTypeHelper {
+			static void register_ifp(ClassManager&, const ClassNameOwning* name);
+		};
+
+		template <typename T, typename... Args>
+		struct CppClassTypeHelper<MakeForeignClass<T, Args...>> {
+			static void register_ifp(ClassManager& classman, const ClassNameOwning* name);
+		};
 	} //namespace detail
 
 	class ClassManager {
+		template <typename F> friend struct detail::CppClassTypeHelper;
 		typedef std::function<foreign_class_t()> make_foreign_class_t;
 		typedef std::unordered_map<detail::ClassNameOwning, make_foreign_class_t, detail::ClassNameHash, detail::ClassNameEqual> ClassMap;
+		typedef std::unordered_map<ClassManagerNameHashType, const detail::ClassNameOwning*> TypeMap;
 	public:
 		ClassManager();
 		~ClassManager() noexcept;
 
-		ClassManager& add_class_maker (std::string_view module_name, std::string_view class_name, make_foreign_class_t);
+		template <typename F>
+		ClassManager& add_class_maker (std::string module_name, std::string_view class_name, F&& maker);
 		foreign_class_t make_class(std::string_view module_name, std::string_view class_name);
+		ModuleAndName wren_class_name_from_hash(ClassManagerNameHashType hash) const;
+		template <typename T>
+		ModuleAndName wren_class_name_from_type() const;
 
 	private:
+		ClassMap::const_iterator add_class_maker_implem (
+			std::string_view module_name,
+			std::string_view class_name,
+			make_foreign_class_t
+		);
+
+		void add_type (ClassManagerNameHashType hash, const detail::ClassNameOwning* name);
+
 		ClassMap m_classes;
+		TypeMap m_types; //refers to memory in m_classes
 	};
+
+	namespace detail {
+		template <typename F>
+		inline void CppClassTypeHelper<F>::register_ifp(ClassManager&, const ClassNameOwning*) {
+			//Nothing to do
+		}
+
+		template <typename T, typename... Args>
+		inline void CppClassTypeHelper<MakeForeignClass<T, Args...>>::register_ifp(
+			ClassManager& classman,
+			const ClassNameOwning* name
+		) {
+			const auto new_hash = type_hash<T>();
+			classman.add_type(new_hash, name);
+		}
+	} //namespace detail
+
+	template <typename F>
+	inline ClassManager& ClassManager::add_class_maker (std::string module_name, std::string_view class_name, F&& maker) {
+		auto it_new = this->add_class_maker_implem(module_name, class_name, std::forward<F>(maker));
+		const auto& owning_name = it_new->first;
+		detail::CppClassTypeHelper<std::decay_t<F>>::register_ifp(*this, &owning_name);
+		return *this;
+	}
+
+	template <typename T>
+	inline ModuleAndName ClassManager::wren_class_name_from_type() const {
+		return detail::wren_class_name_from_type<T>(*this);
+	}
 } //namespace wren

include/wrenpp/detail/construct_foreign_class.hpp

@@ -17,7 +17,7 @@
 
 #pragma once
 
-#include "wrenpp/vm.hpp"
+#include "../vm.hpp"
 #include "setters_getters.hpp"
 #if defined(WRENPP_WITH_NAME_GUESSING)
 #	include "guess_class_name.hpp"
@@ -123,33 +123,46 @@ namespace wren {
 				static_assert(dummy == 1); //always true
 			}
 		}
+
+		//This is named from the perspective of the user - they say
+		//MakeForeignClass<X> and it will "produce" object of type X. In
+		//reality it produces a functor that does that, and it's that functor
+		//that gets registered into wren, so from the library perspective it
+		//should be called MakeForeignClassMaker
+		template <typename T, typename... Args>
+		class MakeForeignClass {
+		public:
+			MakeForeignClass() = default;
+
+			foreign_class_t operator()() const {
+				detail::static_assert_all_packs_are_unique<Args...>();
+
+				foreign_class_t ret;
+				ret.allocate = [](VM& vm, ModuleAndName mn) {
+					void* const mem = vm.set_slot_new_foreign(0, 0, sizeof(T));
+
+					const auto result = detail::ForeignClassHelper<T, Args...>::construct(vm, vm.slot_count() - 1, mem);
+					if (not result.success) {
+						set(vm, 1, std::string{"No registered c++ constructor "} +
+#if defined(WRENPP_WITH_NAME_GUESSING)
+							"for class " + guess_class_name<T>() + " " +
+#endif
+							"takes " + std::to_string(result.parameter_count) +
+							" parameter" + (result.parameter_count == 1 ? "" : "s")
+						);
+						vm.abort_fiber(1);
+					}
+				};
+				ret.finalize = [](void* mem) {
+					const auto cale = static_cast<T*>(mem);
+					cale->~T();
+				};
+
+				return ret;
+			}
+		};
 	} //namespace detail
 
 	template <typename T, typename... Args>
-	inline foreign_class_t make_foreign_class() {
+	constexpr detail::MakeForeignClass<T, Args...> make_foreign_class;
-		detail::static_assert_all_packs_are_unique<Args...>();
-
-		foreign_class_t ret;
-		ret.allocate = [](VM& vm, ModuleAndName mn) {
-			void* const mem = vm.set_slot_new_foreign(0, 0, sizeof(T));
-
-			const auto result = detail::ForeignClassHelper<T, Args...>::construct(vm, vm.slot_count() - 1, mem);
-			if (not result.success) {
-				set(vm, 1, std::string{"No registered c++ constructor "} +
-#if defined(WRENPP_WITH_NAME_GUESSING)
-					"for class " + guess_class_name<T>() + " " +
-#endif
-					"takes " + std::to_string(result.parameter_count) +
-					" parameter" + (result.parameter_count == 1 ? "" : "s")
-				);
-				vm.abort_fiber(1);
-			}
-		};
-		ret.finalize = [](void* mem) {
-			const auto cale = static_cast<T*>(mem);
-			cale->~T();
-		};
-
-		return ret;
-	}
 } //namespace wren

include/wrenpp/detail/meson.build

@@ -8,6 +8,7 @@ include_files = [
   'string_bt.hpp',
   'StringCRC32.hpp',
   'strings_in_vector.hpp',
+  'wren_class_name_from_type.hpp',
   'wren_types.hpp',
 ]
 

include/wrenpp/detail/module_and_name.hpp

@@ -41,6 +41,7 @@ namespace wren {
 	//spits out.
 	class ModuleAndName {
 	public:
+		constexpr ModuleAndName();
 		constexpr ModuleAndName (const char* base, std::uint32_t hash, std::size_t mod_name_len, std::size_t class_name_len);
 
 		constexpr const char* module_name_char() const noexcept { return m_base; }
@@ -73,6 +74,10 @@ namespace wren {
 		static_assert(sizeof(raw) == sizeof(module_and_name));
 	};
 
+	constexpr ModuleAndName::ModuleAndName() :
+		ModuleAndName(nullptr, 0, 0, 0)
+	{}
+
 	constexpr ModuleAndName::ModuleAndName (const char* base, std::uint32_t hash, std::size_t mod_name_len, std::size_t class_name_len) :
 		m_base(base),
 		m_hash(hash),

include/wrenpp/detail/setters_getters.hpp

@@ -17,7 +17,7 @@
 
 #pragma once
 
-#include "wrenpp/vm.hpp"
+#include "../vm.hpp"
 #include <string_view>
 #include <vector>
 #include <tuple>

include/wrenpp/detail/strings_in_vector.hpp

@@ -81,6 +81,10 @@ namespace wren {
 		bool operator== (const StringsInVectorImplem& other) const;
 		bool operator< (const StringsInVectorImplem& other) const;
 
+	protected:
+		const char* raw_buffer() const;
+		std::size_t raw_buffer_size() const;
+
 	private:
 		std::vector<char> m_memory;
 	};
@@ -132,6 +136,16 @@ namespace wren {
 		return this_memory < other_memory;
 	}
 
+	template <std::size_t Count, std::size_t... Indices>
+	inline const char* StringsInVectorImplem<Count, std::index_sequence<Indices...>>::raw_buffer() const {
+		return m_memory.data();
+	}
+
+	template <std::size_t Count, std::size_t... Indices>
+	inline std::size_t StringsInVectorImplem<Count, std::index_sequence<Indices...>>::raw_buffer_size() const {
+		return m_memory.size();
+	}
+
 	template <std::size_t Count>
 	using StringsInVector = StringsInVectorImplem<Count, decltype(std::make_index_sequence<Count>())>;
 

include/wrenpp/detail/wren_class_name_from_type.hpp

@@ -0,0 +1,51 @@
+/* Copyright 2020-2022, Michele Santullo
+ * This file is part of wrenpp.
+ *
+ * Wrenpp is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Wrenpp is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with wrenpp.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "module_and_name.hpp"
+#include <utility>
+#include <string_view>
+#include <cstddef>
+
+namespace wren {
+	typedef std::size_t ClassManagerNameHashType;
+	class VM;
+
+	namespace detail {
+		//TODO: work in progress, make it take a type T and hash that for real
+		template<typename T>
+		inline ClassManagerNameHashType type_hash() {
+			static const ClassManagerNameHashType my_hash = 0;
+			return static_cast<ClassManagerNameHashType>(reinterpret_cast<std::uintptr_t>(&my_hash));
+		}
+
+		//Just an utility function to call a method on the class manager in vm
+		//and return its return value without including the header for the
+		//class manager. Useful in inline functions in header files where
+		//including class_manager.hpp would propagate it everywhere.
+		ModuleAndName fetch_class_name_from_manager (
+			const VM& vm,
+			ClassManagerNameHashType hash
+		);
+
+		template <typename T>
+		inline ModuleAndName wren_class_name_from_type (const VM& vm) {
+			return fetch_class_name_from_manager(vm, type_hash<T>());
+		}
+	} //namespace detail
+} //namespace wren

include/wrenpp/vm.hpp

@@ -109,7 +109,9 @@ namespace wren {
 		void reset (Configuration* conf);
 
 		CallbackManager& callback_manager();
+		const CallbackManager& callback_manager() const;
 		ClassManager& class_manager();
+		const ClassManager& class_manager() const;
 
 	private:
 		struct LocalData;

include/wrenpp/vm_fun.hpp

@@ -25,6 +25,7 @@
 #include "detail/wren_types.hpp"
 #include "detail/construct_foreign_class.hpp"
 #include "detail/setters_getters.hpp"
+#include "detail/wren_class_name_from_type.hpp"
 #include <string>
 #include <string_view>
 #include <type_traits>
@@ -103,8 +104,15 @@ namespace wren {
 					}
 					else {
 						auto ret = call_implem(std::make_integer_sequence<int, sizeof...(Args)>(), vm);
+						//TODO: check for errors
 						vm.ensure_slots(1);
-						set(vm, 0, ret);
+						if constexpr (std::is_fundamental<R>::value) {
+							set(vm, 0, ret);
+						}
+						else {
+							ModuleAndName wren_name = wren_class_name_from_type<R>(vm);
+							R* const new_object = make_wren_object<R>(vm, wren_name, std::move(ret));
+						}
 					}
 				};
 			}

meson.build

@@ -68,6 +68,7 @@ wrenpp = library(meson.project_name(),
   'src/vm_fun.cpp',
   'src/callback_manager.cpp',
   'src/class_manager.cpp',
+  'src/wren_class_name_from_type.cpp',
   dependencies: [wren_dep],
   include_directories: public_incl,
   install: (not meson.is_subproject() or get_option('default_library')=='shared'),

src/class_manager.cpp

@@ -16,6 +16,7 @@
  */
 
 #include "wrenpp/class_manager.hpp"
+#include <cassert>
 
 namespace wren {
 	namespace detail {
@@ -36,6 +37,15 @@ namespace wren {
 		{
 		}
 
+		ClassNameOwning::operator ModuleAndName() const {
+			return ModuleAndName{
+				this->raw_buffer(),
+				0, //TODO: replace with hash
+				this->module_name().size(),
+				this->class_name().size()
+			};
+		}
+
 		bool ClassNameOwning::operator== (const ClassNameOwning& other) const {
 			return
 				*static_cast<const ClassNameBase*>(this) == static_cast<const ClassNameBase&>(other) or
@@ -74,19 +84,6 @@ namespace wren {
 	ClassManager::ClassManager() = default;
 	ClassManager::~ClassManager() noexcept = default;
 
-	ClassManager& ClassManager::add_class_maker (std::string_view module_name, std::string_view class_name, make_foreign_class_t maker) {
-		using detail::TempClassName;
-		using detail::ClassNameOwning;
-
-		auto it_found = m_classes.find(TempClassName{module_name, class_name});
-		if (m_classes.cend() == it_found)
-			m_classes.insert(it_found, std::make_pair(ClassNameOwning{module_name, class_name}, maker));
-		else
-			it_found->second = maker;
-
-		return *this;
-	}
-
 	foreign_class_t ClassManager::make_class (std::string_view module_name, std::string_view class_name) {
 		using detail::TempClassName;
 
@@ -96,4 +93,47 @@ namespace wren {
 		else
 			return {nullptr, nullptr};
 	}
+
+	auto ClassManager::add_class_maker_implem (
+		std::string_view module_name,
+		std::string_view class_name,
+		make_foreign_class_t maker
+	) -> ClassMap::const_iterator {
+		using detail::TempClassName;
+		using detail::ClassNameOwning;
+
+		auto it_found = m_classes.find(TempClassName{module_name, class_name});
+		ClassMap::const_iterator retval;
+		if (m_classes.cend() == it_found) {
+			retval = m_classes.insert(
+				it_found,
+				std::make_pair(ClassNameOwning{module_name, class_name}, maker)
+			);
+		}
+		else {
+			it_found->second = maker;
+			retval = it_found;
+		}
+
+		return retval;
+	}
+
+	void ClassManager::add_type (ClassManagerNameHashType hash, const detail::ClassNameOwning* name) {
+		using detail::TempClassName;
+
+		assert(m_types.count(hash) == 0 or m_types.at(hash) == name);
+		//insert if not present, leave old value if hash is already there
+		m_types.insert(std::make_pair(hash, name));
+	}
+
+	ModuleAndName ClassManager::wren_class_name_from_hash(ClassManagerNameHashType hash) const {
+		const auto it_found = m_types.find(hash);
+		if (m_types.cend() != it_found) {
+			const detail::ClassNameOwning* const name = it_found->second;
+			return *name;
+		}
+		else {
+			return {};
+		}
+	}
 } //namespace wren

src/vm.cpp

@@ -289,6 +289,7 @@ namespace wren {
 	}
 
 	bool VM::has_module(const char* module) const noexcept {
+		assert(module);
 		return wrenHasModule(m_local->wvm, module);
 	}
 
@@ -348,10 +349,18 @@ namespace wren {
 		return m_local->callback_manager;
 	}
 
+	const CallbackManager& VM::callback_manager() const {
+		return m_local->callback_manager;
+	}
+
 	ClassManager& VM::class_manager() {
 		return m_local->class_manager;
 	}
 
+	const ClassManager& VM::class_manager() const {
+		return m_local->class_manager;
+	}
+
 	void VM::ensure_slots (int num_slots) {
 		wrenEnsureSlots(m_local->wvm, num_slots);
 	}

src/wren_class_name_from_type.cpp

@@ -0,0 +1,14 @@
+#include "wrenpp/detail/wren_class_name_from_type.hpp"
+#include "wrenpp/vm.hpp"
+#include "wrenpp/class_manager.hpp"
+
+namespace wren {
+	namespace detail {
+		ModuleAndName fetch_class_name_from_manager (
+			const VM& vm,
+			ClassManagerNameHashType hash
+		) {
+			return vm.class_manager().wren_class_name_from_hash(hash);
+		}
+	} //namespace detail
+} //namespace wren