Added `ptr::Unique<T>`: `NonNull<T>` that cannot be aliased.

Fortune for libexopt's current commit: Future small blessing − 末小吉

include/error.hh

@@ -1,5 +1,9 @@
 #pragma once
 
+#include <stdexcept>
+#include <stacktrace>
+#include <source_location>
+
 #include "exopt.h"
 
 #include "optional.h"
@@ -7,16 +11,24 @@
 
 
 namespace exopt {
+	// Report generated from an error. (virtual base, not abstract.)
 	class Report {
+	public:
 		virtual ~Report();
 	};
+	// This is propagated returned (base, abstract)
 	class Error {
-		constexpr Error() = default;
+	public:
 		constexpr Error(Error const&) = default;
 		constexpr Error(Error &&) = default;
 		constexpr Error& operator=(Error &&) = default;
 		constexpr Error& operator=(Error const&) = default;
 
+
+		constexpr virtual std::source_location const& location() const noexcept { return m_location; }
+
+		constexpr operator std::string_view() const noexcept { return message(); }
+
 		constexpr virtual std::string_view message() const noexcept =0;
 
 		constexpr virtual MaybeOwnedRef<Error> inner() noexcept { return {}; } //TODO: Maybe just use `std::optional<std::reference_wrapper<Error>>`
@@ -25,7 +37,37 @@ namespace exopt {
 
 		constexpr virtual ~Error() = default;
 	protected:
+		constexpr Error(std::source_location loc = std::source_location::current()) noexcept
+			: m_location(std::move(loc)) {}
+	private:
+		std::source_location m_location;
+		//Moved this to non-constexpr subclass `TracedError` \
+			std::unique_ptr<std::stacktrace> m_trace{nullptr}; //TODO: Change to exopt::types::Box<> to make copy ctor/assign work
+	};
 
+	// This is propagated returned, along with a stack trace. (base, abstract)
+	class TracedError : Error {
+	public:
+		TracedError(TracedError const &) = default;
+		TracedError(TracedError &&) = default;
+		TracedError& operator=(TracedError &&) = default;
+		TracedError& operator=(TracedError const&) = default;
+		virtual ~TracedError() = default;
+
+		inline virtual std::stacktrace const& stacktrace() const noexcept { return m_trace; }
+
+	protected:
+		inline TracedError(
+				std::source_location loc = std::source_location::current()
+				, std::stacktrace trace = std::stacktrace::current()) noexcept
+			: Error(std::move(loc)), m_trace(std::move(trace)) {}
 	private:
+		std::stacktrace m_trace; //TODO: Maybe box this? idk how big it is...
+	};
+
+	// This is thrown. (virtual base, abstract)
+	class Panic : /*virtual?? I think it should be XXX*/ Error {
+		//TODO: How to make a `constexpr` deduced panic that has stack-trace at runtime only? Is it needed? Hnm...
 	};
+	//TODO: Fatal(string) : public virtual Panic
 }

include/optional.h

@@ -21,6 +21,16 @@ namespace exopt::types { namespace optional [[gnu::visibility("internal")]] {
 		constexpr static inline auto sentinel = nullptr;
 	};
 
+	template<typename T>
+	struct null_optimise<ptr::Unique<T> > { constexpr static inline bool value = true;
+		using held_type = T __restrict__*;
+		using type = ptr::Unique<T>;
+		constexpr static decltype(auto) convert_to_held(std::add_rvalue_reference_t<type> t) noexcept { return t.get(); }
+		constexpr static decltype(auto) convert_from_held(std::add_rvalue_reference_t<held_type> t) noexcept { return ptr::Unique<T>::new_unchecked(t); }
+
+		constexpr static inline auto sentinel = nullptr;
+	};
+
 	template<typename T>
 	struct null_optimise<T&> { constexpr static inline bool value = true;
 		using held_type = T*;
@@ -535,6 +545,8 @@ namespace exopt::types { namespace optional [[gnu::visibility("internal")]] {
 	static_assert(alignof(Option<void*>) == alignof(void*), "Option<T*>: Bad null_opt align");
 	static_assert(sizeof(Option<ptr::NonNull<int>>) == sizeof(int*), "Option<NonNull<T>>: Bad null_opt size");
 	static_assert(alignof(Option<ptr::NonNull<int>>) == alignof(int*), "Option<NonNull<T>>: Bad null_opt align");
+	static_assert(sizeof(Option<ptr::Unique<int>>) == sizeof(int*), "Option<Unique<T>>: Bad null_opt size");
+	static_assert(alignof(Option<ptr::Unique<int>>) == alignof(int*), "Option<Unique<T>>: Bad null_opt align");
 	static_assert(sizeof(Option<double&>) == sizeof(double&), "Option<T&>: Bad null_opt size");
 	static_assert(alignof(Option<double&>) == alignof(double*), "Option<T&>: Bad null_opt align");
 	static_assert(sizeof(Option<long long int&&>) == sizeof(char*), "Option<T&&>: Bad null_opt size");

include/pointer.h

@@ -13,9 +13,11 @@ namespace exopt::ptr {
 	using RawRef = T&;
 
 	template<typename T>
-	using UniquePtr = T* __restrict__;
+	using UniquePtr = T __restrict__*;
 	template<typename T>
-	using UniqueRef = T& __restrict__;
+	using UniqueRef = T __restrict__&;
+	template<typename T>
+	using UniqueMoveRef = T __restrict__&&;
 
 	template<typename T>
 	using AliasedPtr = T __attribute__((__may_alias__))*;
@@ -136,6 +138,8 @@ namespace exopt::ptr {
 		constexpr virtual ~NullException() noexcept {}
 
 		constexpr std::string_view message() const noexcept /*override*/ { return "pointer was null"; }
+
+		std::runtime_error as_runtime() &&noexcept; /*TODO: override*/ 
 	};
 
 	template<typename T> requires(!std::is_reference_v<T>)
@@ -158,7 +162,7 @@ namespace exopt::ptr {
 		constexpr ~NonNull() noexcept = default;
 
 		constexpr static NonNull<T> try_new(T* ptr) {
-			if(!ptr) _throw_null();
+			if(__builtin_expect(!ptr, false)) _throw_null();
 			return NonNull<T>{ptr};
 		}
 #ifdef DEBUG
@@ -235,14 +239,95 @@ namespace exopt::ptr {
 		constexpr const T* operator->() const noexcept { return ptr_; }
 	private:	
 		[[noreturn, gnu::noinline, gnu::cold]]
-		constexpr void _throw_null() {
+		constexpr static void _throw_null() {
 			if consteval {
 				throw NullException{};
 			} else {
-				throw std::runtime_error(NullException{}.message());
+				//std::terminate();
+				throw NullException{}.as_runtime();
+				//::exopt::util::throw_runtime(NullException{}); //XXX: Wut?
 			}
 			//throw error::as_runtime_error(error::comptime_fail<NullException>());
 		}
 		T* ptr_;
 	};
+
+	/// Holds a *unique reference* that cannot be aliased, and cannot be null.
+	template<typename T> requires(!std::is_reference_v<T>)
+	struct Unique {	
+		using value_type = std::remove_cv_t<std::decay_t<T>>;
+
+		using reference_type = UniqueRef<value_type>;
+		using const_reference_type = UniqueRef<value_type const>;
+		using move_reference_type = UniqueMoveRef<value_type>;
+
+		using pointer_type = UniquePtr<value_type>;
+		using const_pointer_type = UniquePtr<value_type const>;
+
+		constexpr static inline bool is_mutable = !std::is_same_v<pointer_type, const_pointer_type>;
+
+		constexpr static Unique<T> try_new(pointer_type const&& ptr)
+		{
+			return { NonNull<T>::try_new(ptr) };
+		}
+#ifdef DEBUG
+		[[gnu::nonnull(1)]]
+#endif
+		constexpr static Unique<T> new_unchecked(pointer_type ptr) noexcept { 
+#ifndef DEBUG
+			_EO_ASSUME(ptr!=nullptr); 
+#endif
+		return { NonNull<T>{ ptr } }; }
+	
+		constexpr Unique(std::convertible_to<NonNull<value_type>> auto const&& ptr) noexcept
+			: m_ptr(ptr) {}
+		[[gnu::nonnull(1,2)]]
+		constexpr explicit Unique(T* __restrict__ ptr) noexcept
+			: m_ptr(ptr) {}
+
+		constexpr Unique(Unique&&) noexcept = default;
+		constexpr Unique& operator=(Unique&&) noexcept = default;
+
+		constexpr Unique(const Unique&) = delete;
+		constexpr Unique& operator=(const Unique&) = delete;
+
+		constexpr ~Unique() noexcept = default;
+
+		constexpr friend bool operator==(std::nullptr_t, const Unique& __restrict__) noexcept { return false; }
+		constexpr friend bool operator==(const Unique& __restrict__, std::nullptr_t) noexcept { return false; }
+
+		constexpr friend bool operator!=(std::nullptr_t, const Unique& __restrict__) noexcept { return true; }
+		constexpr friend bool operator!=(const Unique& __restrict__, std::nullptr_t) noexcept { return true; }
+
+		constexpr friend auto operator<=>(const Unique& __restrict__ a, const Unique& __restrict__ b) noexcept { return a.get() <=> b.get(); }
+		constexpr friend auto operator<=>(const Unique& __restrict__ a, T* __restrict__ b) noexcept { return (!b) ? (true<=>false) : (a.get() <=> b); }
+		constexpr friend auto operator<=>(T* __restrict__ a, const Unique& __restrict__ b) noexcept { return (!a) ? (false<=>true) : (a <=> b.get()); }
+
+		[[gnu::returns_nonnull]]
+		constexpr pointer_type get() const __restrict__ noexcept { return m_ptr.get(); }
+
+		[[gnu::returns_nonnull]]
+		constexpr operator pointer_type() const __restrict__ noexcept { return get(); }
+		constexpr explicit operator NonNull<T>() const  noexcept { return m_ptr; }
+
+		constexpr reference_type operator*() __restrict__ & noexcept { return *get(); }
+		constexpr const_reference_type operator*() const __restrict__& noexcept { return *get(); }
+		constexpr move_reference_type operator*() __restrict__ &&noexcept { return std::move(*get()); }
+		constexpr decltype(auto) operator*() const __restrict__ &&noexcept { return *get(); }
+
+		[[gnu::returns_nonnull]]
+		constexpr pointer_type operator->() __restrict__ noexcept { return get(); }
+		[[gnu::returns_nonnull]]
+		constexpr const_pointer_type operator->() const __restrict__ noexcept { return get(); }
+	private:
+		NonNull<T> m_ptr;
+	};
+#if 0
+	consteval bool uniq_check() noexcept {
+		int ptr = 0;
+		int* const ptr0 = &ptr;
+		return Unique<int>::try_new(std::move(ptr0)).get() == &ptr;
+	}
+	static_assert(uniq_check(), "Invalid Unique<>.get()");
+#endif
 }

include/util.hh

@@ -63,4 +63,41 @@ namespace exopt { namespace util [[gnu::visibility("internal")]] {
 		};
 		return _array_create(std::move(a), _I{});
 	}
+
+	struct [[gnu::visibility("internal")]]  CTInternalFatalError  {
+		constexpr CTInternalFatalError() noexcept = default;
+		constexpr CTInternalFatalError(CTInternalFatalError const&) noexcept = default;
+		constexpr CTInternalFatalError(CTInternalFatalError &&) noexcept = default;
+		constexpr CTInternalFatalError& operator=(CTInternalFatalError const&) noexcept = default;
+		constexpr CTInternalFatalError& operator=(CTInternalFatalError&&) noexcept = default;
+		constexpr virtual ~CTInternalFatalError() noexcept = default;
+
+		constexpr operator std::string_view() const noexcept { return message(); }
+
+		consteval virtual std::string_view message() const noexcept =0;
+	};
+
+	[[noreturn, gnu::noinline, gnu::cold]]
+	void throw_runtime(std::string_view&&);	
+
+	[[noreturn]]//, gnu::noinline, gnu::cold]]
+	constexpr void throw_runtime(std::convertible_to<std::string_view> auto&& msg) {
+		std::string_view view{msg};
+		if consteval {
+			using CTE = CTInternalFatalError; 
+			struct CTIFRuntimeError : public CTE {
+				using CTE::CTE;
+				consteval CTIFRuntimeError(std::string_view&& view) noexcept
+					: CTE(), m_message(std::move(view)) {}
+				consteval std::string_view message() const noexcept override { return m_message; }
+				constexpr virtual ~CTIFRuntimeError() noexcept {}
+			private:
+				std::string_view m_message;
+			};
+			throw CTIFRuntimeError(std::move(view));
+		} else {
+			throw_runtime(std::move(view));
+		}
+		__builtin_unreachable();
+	}
 } }

src/ptr.cpp

@@ -0,0 +1,9 @@
+
+
+#include <string>
+
+#include "pointer.h"
+
+namespace exopt::ptr {
+	std::runtime_error NullException::as_runtime() &&noexcept { return std::runtime_error{std::string{message()} }; }
+}

src/util.cpp

@@ -0,0 +1,15 @@
+
+#include <string>
+#include <stdexcept>
+
+#include <util.hh>
+
+namespace exopt {
+	namespace util [[gnu::visibility("internal")]] {
+	
+		[[noreturn, gnu::noinline, gnu::cold]]
+		void throw_runtime(std::string_view&& msg) {
+			throw std::runtime_error(std::string{std::move(msg)});
+		}
+	}
+}