feat: view::edges customization point

DNKpp · Oct 5, 2023 · 1669886 · 1669886
1 parent c6d4edd
commit 1669886
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Showing 2 changed files with 169 additions and 25 deletions.
diff --git a/include/Simple-Utility/graph/View.hpp b/include/Simple-Utility/graph/View.hpp
@@ -13,46 +13,116 @@
 #include "Simple-Utility/graph/Node.hpp"
 
 #include <concepts>
-#include <ranges>
+// ReSharper disable once CppUnusedIncludeDirective
+#include <ranges>	// std::ranges::input_range, etc.
 
 namespace sl::graph::view
 {
-	template <class>
+	template <typename>
 	struct traits;
+
+	template <typename T>
+	using edge_t = typename traits<T>::edge_type;
+
+	template <typename T>
+		requires requires { typename T::edge_type; }
+				&& concepts::edge<typename T::edge_type>
+	struct traits<T>
+	{
+		using edge_type = typename T::edge_type;
+	};
+}
+
+namespace sl::graph::customize
+{
+	template <typename>
+	struct edges_fn;
+}
+
+namespace sl::graph::detail
+{
+	template <typename View, typename Node>
+		requires requires { customize::edges_fn<View>{}; }
+				&& std::ranges::input_range<std::invoke_result_t<customize::edges_fn<View>, const View&, const Node&>>
+				&& std::convertible_to<
+					std::ranges::range_reference_t<std::invoke_result_t<customize::edges_fn<View>, const View&, const Node&>>,
+					view::edge_t<View>>
+	constexpr decltype(auto) edges(
+		const View& view,
+		const Node& node,
+		const priority_tag<2>
+	) noexcept(noexcept(customize::edges_fn<View>{}(view, node)))
+	{
+		return customize::edges_fn<View>{}(view, node);
+	}
+
+	template <typename View, typename Node>
+		requires requires(const View& view, const Node& node)
+		{
+			{ view.edges(node) } -> std::ranges::input_range;
+			requires std::convertible_to<
+				std::ranges::range_reference_t<decltype(view.edges(node))>,
+				view::edge_t<View>>;
+		}
+	constexpr decltype(auto) edges(const View& view, const Node& node, const priority_tag<1>) noexcept(noexcept(view.edges(node)))
+	{
+		return view.edges(node);
+	}
+
+	template <typename View, typename Node>
+		requires requires(const View& view, const Node& node)
+		{
+			{ edges(view, node) } -> std::ranges::input_range;
+			requires std::convertible_to<
+				std::ranges::range_reference_t<decltype(edges(view, node))>,
+				view::edge_t<View>>;
+		}
+	constexpr decltype(auto) edges(const View& view, const Node& node, const priority_tag<0>) noexcept(noexcept(edges(view, node)))
+	{
+		return edges(view, node);
+	}
+
+	struct edges_fn
+	{
+		template <typename View, typename Node>
+			requires requires(const View& view, const Node& node, const priority_tag<2> tag)
+			{
+				{ detail::edges(view, node, tag) } -> std::ranges::input_range;
+				requires std::convertible_to<
+					std::ranges::range_reference_t<decltype(detail::edges(view, node, tag))>,
+					view::edge_t<View>>;
+			}
+		constexpr decltype(auto) operator ()(
+			const View& view,
+			const Node& node
+		) const noexcept(noexcept(detail::edges(view, node, priority_tag<2>{})))
+		{
+			return detail::edges(view, node, priority_tag<2>{});
+		}
+	};
+}
+
+namespace sl::graph::view
+{
+	inline constexpr detail::edges_fn edges{};
 }
 
 namespace sl::graph::concepts
 {
-	template <class T, class Node>
+	template <typename T, typename Node>
 	concept view_for = basic_node<Node>
 						&& sl::concepts::unqualified<T>
 						&& requires(const T& view, const Node& node)
 						{
 							// fixes compile error on msvc v142
 							// ReSharper disable once CppRedundantTemplateKeyword
 							typename view::template traits<T>::edge_type;
-							// ReSharper disable once CppRedundantTemplateKeyword
-							requires edge_for<typename view::template traits<T>::edge_type, Node>;
-							{ view.edges(node) } -> std::ranges::input_range;
+							requires edge_for<view::edge_t<T>, Node>;
+							{ view::edges(view, node) } -> std::ranges::input_range;
 							requires std::convertible_to<
-								std::ranges::range_value_t<decltype(view.edges(node))>,
-								// ReSharper disable once CppRedundantTemplateKeyword
-								typename view::template traits<T>::edge_type>;
+								std::ranges::range_value_t<std::invoke_result_t<detail::edges_fn, const T&, const Node&>>,
+								view::edge_t<T>>;
 						};
 }
 
-namespace sl::graph::view
-{
-	template <class T>
-	using edge_t = typename traits<T>::edge_type;
-
-	template <class T>
-		requires requires { typename T::edge_type; }
-				&& concepts::edge<typename T::edge_type>
-	struct traits<T>
-	{
-		using edge_type = typename T::edge_type;
-	};
-}
-
 #endif
diff --git a/tests/graph/View.cpp b/tests/graph/View.cpp
@@ -11,6 +11,32 @@
 
 namespace
 {
+	struct member_fun_get_edges
+	{
+		using edge_type = GenericBasicEdge<std::string>;
+
+		MAKE_CONST_MOCK1(edges, std::vector<edge_type>(const GenericBasicNode<std::string>&));
+	};
+
+	struct free_fun_get_edges
+	{
+		using edge_type = GenericBasicEdge<std::string>;
+
+		MAKE_CONST_MOCK1(get_edges, std::vector<edge_type>(const GenericBasicNode<std::string>&));
+
+		friend std::vector<edge_type> edges(const free_fun_get_edges& obj, const GenericBasicNode<std::string>& node)
+		{
+			return obj.get_edges(node);
+		}
+	};
+
+	struct customized_get_edges
+	{
+		using edge_type = GenericBasicEdge<std::string>;
+
+		MAKE_CONST_MOCK1(get_edges, std::vector<edge_type>(const GenericBasicNode<std::string>&));
+	};
+
 	template <sg::concepts::vertex Vertex>
 	struct GenericBasicView
 	{
@@ -19,9 +45,11 @@ namespace
 		template <sg::concepts::basic_node Node>
 			requires sg::concepts::edge_for<edge_type, Node>
 		// ReSharper disable once CppFunctionIsNotImplemented
-		static std::vector<edge_type> edges(const Node&);
+		static std::vector<edge_type> edges(const Node&); // NOLINT(clang-diagnostic-undefined-internal)
 	};
 
+	static_assert(sg::concepts::view_for<GenericBasicView<std::string>, GenericBasicNode<std::string>>);
+
 	template <sg::concepts::vertex Vertex, sg::concepts::weight Weight>
 	struct GenericWeightedView
 	{
@@ -30,10 +58,56 @@ namespace
 		template <sg::concepts::basic_node Node>
 			requires sg::concepts::edge_for<edge_type, Node>
 		// ReSharper disable once CppFunctionIsNotImplemented
-		static std::vector<edge_type> edges(const Node&);
+		static std::vector<edge_type> edges(const Node&); // NOLINT(clang-diagnostic-undefined-internal)
 	};
 }
 
+template <>
+struct sl::graph::customize::edges_fn<customized_get_edges>
+{
+	[[nodiscard]]
+	auto operator ()(const customized_get_edges& e, const GenericBasicNode<std::string>& node) const
+	{
+		return e.get_edges(node);
+	}
+};
+
+TEST_CASE(
+	"graph::view::edges serves as a customization point, returning the outgoing edges of the given node.",
+	"[graph][graph::view]")
+{
+	const GenericBasicNode<std::string> node{"Hello, World!"};
+	const std::vector<GenericBasicEdge<std::string>> expected{
+		{"Edge0"},
+		{"Edge1"},
+		{"Edge2"}
+	};
+
+	SECTION("Access via the member function.")
+	{
+		const member_fun_get_edges mock{};
+		REQUIRE_CALL(mock, edges(node))
+			.RETURN(expected);
+		REQUIRE(expected == sg::view::edges(mock, node));
+	}
+
+	SECTION("Access via the free function.")
+	{
+		const free_fun_get_edges mock{};
+		REQUIRE_CALL(mock, get_edges(node))
+			.RETURN(expected);
+		REQUIRE(expected == sg::view::edges(mock, node));
+	}
+
+	SECTION("Access via customized function.")
+	{
+		const customized_get_edges mock{};
+		REQUIRE_CALL(mock, get_edges(node))
+			.RETURN(expected);
+		REQUIRE(expected == sg::view::edges(mock, node));
+	}
+}
+
 TEMPLATE_TEST_CASE_SIG(
 	"view::traits extracts edge type.",
 	"[graph][graph::view]",