mirror of https://github.com/tstack/lnav.git
984 lines
26 KiB
C++
984 lines
26 KiB
C++
/*
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Mathieu Stefani, 03 mai 2016
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This header provides a Result type that can be used to replace exceptions in code
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that has to handle error.
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Result<T, E> can be used to return and propagate an error to the caller. Result<T, E> is an algebraic
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data type that can either Ok(T) to represent success or Err(E) to represent an error.
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*/
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#pragma once
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#include <stdio.h>
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#include <exception>
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#include <functional>
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#include <type_traits>
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namespace types {
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template<typename T>
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struct Ok {
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Ok(const T& val) : val(val) { }
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Ok(T&& val) : val(std::move(val)) { }
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T val;
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};
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template<>
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struct Ok<void> { };
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template<typename E>
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struct Err {
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Err(const E& val) : val(val) { }
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Err(E&& val) : val(std::move(val)) { }
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E val;
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};
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template<>
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struct Err<void> { };
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};
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template<typename T, typename CleanT = typename std::decay<T>::type>
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types::Ok<CleanT> Ok(T&& val) {
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return types::Ok<CleanT>(std::forward<T>(val));
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}
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inline types::Ok<void> Ok() {
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return {};
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}
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template<typename E, typename CleanE = typename std::decay<E>::type>
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types::Err<CleanE> Err(E&& val) {
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return types::Err<CleanE>(std::forward<E>(val));
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}
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inline types::Err<void> Err() {
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return {};
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}
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template<typename T, typename E> struct Result;
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namespace details {
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template<typename ...> struct void_t { typedef void type; };
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namespace impl {
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template<typename Func> struct result_of;
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template<typename Ret, typename Cls, typename... Args>
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struct result_of<Ret (Cls::*)(Args...)> : public result_of<Ret (Args...)> { };
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template<typename Ret, typename... Args>
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struct result_of<std::function<Ret (Args...)>> {
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typedef Ret type;
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};
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}
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template<typename Func>
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struct result_of : public impl::result_of<decltype(&Func::operator())> { };
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template<typename Ret, typename Cls, typename... Args>
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struct result_of<Ret (Cls::*) (Args...) const> {
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typedef Ret type;
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};
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template<typename Ret, typename... Args>
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struct result_of<Ret (*)(Args...)> {
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typedef Ret type;
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};
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template<typename R>
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struct ResultOkType { typedef typename std::decay<R>::type type; };
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template<typename T, typename E>
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struct ResultOkType<Result<T, E>> {
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typedef T type;
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};
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template<typename R>
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struct ResultErrType { typedef R type; };
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template<typename T, typename E>
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struct ResultErrType<Result<T, E>> {
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typedef typename std::remove_reference<E>::type type;
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};
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template<typename R> struct IsResult : public std::false_type { };
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template<typename T, typename E>
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struct IsResult<Result<T, E>> : public std::true_type { };
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namespace ok {
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namespace impl {
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template<typename T> struct Map;
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template<typename Ret, typename Cls, typename Arg>
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struct Map<Ret (Cls::*)(Arg) const> : public Map<Ret (Arg)> { };
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template<typename Ret, typename Cls, typename Arg>
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struct Map<Ret (Cls::*)(Arg)> : public Map<Ret (Arg)> { };
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// General implementation
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template<typename Ret, typename Arg>
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struct Map<Ret (Arg)> {
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static_assert(!IsResult<Ret>::value,
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"Can not map a callback returning a Result, use then instead");
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template<typename T, typename E, typename Func>
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static Result<Ret, E> map(const Result<T, E>& result, Func func) {
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static_assert(
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std::is_same<T, Arg>::value ||
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std::is_convertible<T, Arg>::value,
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"Incompatible types detected");
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if (result.isOk()) {
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auto res = func(result.storage().template get<T>());
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return types::Ok<Ret>(std::move(res));
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}
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return types::Err<E>(result.storage().template get<E>());
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}
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};
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// Specialization for callback returning void
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template<typename Arg>
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struct Map<void (Arg)> {
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template<typename T, typename E, typename Func>
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static Result<void, E> map(const Result<T, E>& result, Func func) {
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if (result.isOk()) {
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func(result.storage().template get<T>());
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return types::Ok<void>();
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}
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return types::Err<E>(result.storage().template get<E>());
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}
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};
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// Specialization for a void Result
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template<typename Ret>
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struct Map<Ret (void)> {
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template<typename T, typename E, typename Func>
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static Result<Ret, E> map(const Result<T, E>& result, Func func) {
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static_assert(std::is_same<T, void>::value,
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"Can not map a void callback on a non-void Result");
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if (result.isOk()) {
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auto ret = func();
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return types::Ok<Ret>(std::move(ret));
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}
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return types::Err<E>(result.storage().template get<E>());
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}
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};
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// Specialization for callback returning void on a void Result
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template<>
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struct Map<void (void)> {
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template<typename T, typename E, typename Func>
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static Result<void, E> map(const Result<T, E>& result, Func func) {
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static_assert(std::is_same<T, void>::value,
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"Can not map a void callback on a non-void Result");
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if (result.isOk()) {
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func();
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return types::Ok<void>();
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}
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return types::Err<E>(result.storage().template get<E>());
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}
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};
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// General specialization for a callback returning a Result
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template<typename U, typename E, typename Arg>
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struct Map<Result<U, E> (Arg)> {
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template<typename T, typename Func>
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static Result<U, E> map(const Result<T, E>& result, Func func) {
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static_assert(
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std::is_same<T, Arg>::value ||
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std::is_convertible<T, Arg>::value,
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"Incompatible types detected");
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if (result.isOk()) {
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auto res = func(result.storage().template get<T>());
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return res;
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}
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return types::Err<E>(result.storage().template get<E>());
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}
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};
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// Specialization for a void callback returning a Result
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template<typename U, typename E>
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struct Map<Result<U, E> (void)> {
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template<typename T, typename Func>
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static Result<U, E> map(const Result<T, E>& result, Func func) {
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static_assert(std::is_same<T, void>::value, "Can not call a void-callback on a non-void Result");
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if (result.isOk()) {
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auto res = func();
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return res;
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}
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return types::Err<E>(result.storage().template get<E>());
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}
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};
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} // namespace impl
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template<typename Func> struct Map;
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template<typename Ret, typename... Args>
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struct Map<Ret (*) (Args...)> : public impl::Map<Ret (Args...)> { };
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template<typename Ret, typename... Args>
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struct Map<Ret (Args...)> : public impl::Map<Ret (Args...)> { };
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template<typename Ret, typename Cls, typename... Args>
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struct Map<Ret (Cls::*) (Args...)> : public impl::Map<Ret (Args...)> { };
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template<typename Ret, typename Cls, typename... Args>
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struct Map<Ret (Cls::*) (Args...) const> : public impl::Map<Ret (Args...)> { };
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template<typename Ret, typename... Args>
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struct Map<std::function<Ret (Args...)>> : public impl::Map<Ret (Args...)> { };
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} // namespace ok
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namespace err {
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namespace impl {
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template<typename T> struct Map;
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template<typename Ret, typename Cls, typename Arg>
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struct Map<Ret (Cls::*)(Arg) const> {
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static_assert(!IsResult<Ret>::value,
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"Can not map a callback returning a Result, use orElse instead");
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template<typename T, typename E, typename Func>
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static Result<T, Ret> map(const Result<T, E>& result, Func func) {
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if (result.isErr()) {
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auto res = func(result.storage().template get<E>());
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return types::Err<Ret>(res);
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}
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return types::Ok<T>(result.storage().template get<T>());
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}
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template<typename E, typename Func>
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static Result<void, Ret> map(const Result<void, E>& result, Func func) {
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if (result.isErr()) {
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auto res = func(result.storage().template get<E>());
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return types::Err<Ret>(res);
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}
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return types::Ok<void>();
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}
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};
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} // namespace impl
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template<typename Func> struct Map : public impl::Map<decltype(&Func::operator())> { };
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} // namespace err;
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namespace And {
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namespace impl {
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template<typename Func> struct Then;
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template<typename Ret, typename... Args>
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struct Then<Ret (*)(Args...)> : public Then<Ret (Args...)> { };
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template<typename Ret, typename Cls, typename... Args>
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struct Then<Ret (Cls::*)(Args...)> : public Then<Ret (Args...)> { };
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template<typename Ret, typename Cls, typename... Args>
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struct Then<Ret (Cls::*)(Args...) const> : public Then<Ret (Args...)> { };
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template<typename Ret, typename Arg>
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struct Then<Ret (Arg)> {
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static_assert(std::is_same<Ret, void>::value,
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"then() should not return anything, use map() instead");
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template<typename T, typename E, typename Func>
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static Result<T, E> then(const Result<T, E>& result, Func func) {
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if (result.isOk()) {
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func(result.storage().template get<T>());
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}
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return result;
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}
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};
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template<typename Ret>
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struct Then<Ret (void)> {
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static_assert(std::is_same<Ret, void>::value,
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"then() should not return anything, use map() instead");
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template<typename T, typename E, typename Func>
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static Result<T, E> then(const Result<T, E>& result, Func func) {
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static_assert(std::is_same<T, void>::value, "Can not call a void-callback on a non-void Result");
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if (result.isOk()) {
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func();
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}
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return result;
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}
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};
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} // namespace impl
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template<typename Func>
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struct Then : public impl::Then<decltype(&Func::operator())> { };
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template<typename Ret, typename... Args>
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struct Then<Ret (*) (Args...)> : public impl::Then<Ret (Args...)> { };
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template<typename Ret, typename Arg>
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struct Then<Ret (Arg)> : public impl::Then<Ret (Arg)> { };
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template<typename Ret, typename Cls, typename... Args>
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struct Then<Ret (Cls::*)(Args...)> : public impl::Then<Ret (Args...)> { };
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template<typename Ret, typename Cls, typename... Args>
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struct Then<Ret (Cls::*)(Args...) const> : public impl::Then<Ret (Args...)> { };
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template<typename Ret, typename... Args>
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struct Then<std::function<Ret (Args...)>> : public impl::Then<Ret (Args...)> { };
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} // namespace And
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namespace Or {
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namespace impl {
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template<typename Func> struct Else;
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template<typename Ret, typename... Args>
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struct Else<Ret (*)(Args...)> : public Else<Ret (Args...)> { };
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template<typename Ret, typename Cls, typename... Args>
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struct Else<Ret (Cls::*)(Args...)> : public Else<Ret (Args...)> { };
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template<typename Ret, typename Cls, typename... Args>
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struct Else<Ret (Cls::*)(Args...) const> : public Else<Ret (Args...)> { };
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template<typename T, typename F, typename Arg>
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struct Else<Result<T, F> (Arg)> {
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template<typename E, typename Func>
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static Result<T, F> orElse(const Result<T, E>& result, Func func) {
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static_assert(
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std::is_same<E, Arg>::value ||
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std::is_convertible<E, Arg>::value,
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"Incompatible types detected");
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if (result.isErr()) {
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auto res = func(result.storage().template get<E>());
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return res;
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}
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return types::Ok<T>(result.storage().template get<T>());
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}
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template<typename E, typename Func>
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static Result<void, F> orElse(const Result<void, E>& result, Func func) {
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if (result.isErr()) {
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auto res = func(result.storage().template get<E>());
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return res;
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}
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return types::Ok<void>();
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}
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};
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template<typename T, typename F>
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struct Else<Result<T, F> (void)> {
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template<typename E, typename Func>
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static Result<T, F> orElse(const Result<T, E>& result, Func func) {
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static_assert(std::is_same<T, void>::value,
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"Can not call a void-callback on a non-void Result");
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if (result.isErr()) {
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auto res = func();
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return res;
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}
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return types::Ok<T>(result.storage().template get<T>());
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}
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template<typename E, typename Func>
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static Result<void, F> orElse(const Result<void, E>& result, Func func) {
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if (result.isErr()) {
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auto res = func();
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return res;
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}
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return types::Ok<void>();
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}
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};
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} // namespace impl
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template<typename Func>
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struct Else : public impl::Else<decltype(&Func::operator())> { };
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template<typename Ret, typename... Args>
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struct Else<Ret (*) (Args...)> : public impl::Else<Ret (Args...)> { };
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template<typename Ret, typename Cls, typename... Args>
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struct Else<Ret (Cls::*)(Args...)> : public impl::Else<Ret (Args...)> { };
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template<typename Ret, typename Cls, typename... Args>
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struct Else<Ret (Cls::*)(Args...) const> : public impl::Else<Ret (Args...)> { };
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} // namespace Or
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namespace Other {
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namespace impl {
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template<typename Func> struct Wise;
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template<typename Ret, typename... Args>
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struct Wise<Ret (*)(Args...)> : public Wise<Ret (Args...)> { };
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template<typename Ret, typename Cls, typename... Args>
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struct Wise<Ret (Cls::*)(Args...)> : public Wise<Ret (Args...)> { };
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template<typename Ret, typename Cls, typename... Args>
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struct Wise<Ret (Cls::*)(Args...) const> : public Wise<Ret (Args...)> { };
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template<typename Ret, typename Arg>
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struct Wise<Ret (Arg)> {
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template<typename T, typename E, typename Func>
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static Result<T, E> otherwise(const Result<T, E>& result, Func func) {
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static_assert(
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std::is_same<E, Arg>::value ||
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std::is_convertible<E, Arg>::value,
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"Incompatible types detected");
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static_assert(std::is_same<Ret, void>::value,
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"callback should not return anything, use mapError() for that");
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if (result.isErr()) {
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func(result.storage().template get<E>());
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}
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return result;
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}
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};
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} // namespace impl
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template<typename Func>
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struct Wise : public impl::Wise<decltype(&Func::operator())> { };
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template<typename Ret, typename... Args>
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struct Wise<Ret (*) (Args...)> : public impl::Wise<Ret (Args...)> { };
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template<typename Ret, typename Cls, typename... Args>
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struct Wise<Ret (Cls::*)(Args...)> : public impl::Wise<Ret (Args...)> { };
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template<typename Ret, typename Cls, typename... Args>
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struct Wise<Ret (Cls::*)(Args...) const> : public impl::Wise<Ret (Args...)> { };
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} // namespace Other
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template<typename T, typename E, typename Func>
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decltype(auto) map(const Result<T, E>& result, Func func) {
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return ok::Map<Func>::map(result, func);
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}
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template<typename T, typename E, typename Func,
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typename Ret =
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Result<T,
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typename details::ResultErrType<
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typename details::result_of<Func>::type
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>::type
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>
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>
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Ret mapError(const Result<T, E>& result, Func func) {
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return err::Map<Func>::map(result, func);
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}
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template<typename T, typename E, typename Func>
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Result<T, E> then(const Result<T, E>& result, Func func) {
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return And::Then<Func>::then(result, func);
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}
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template<typename T, typename E, typename Func>
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Result<T, E> otherwise(const Result<T, E>& result, Func func) {
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return Other::Wise<Func>::otherwise(result, func);
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}
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template<typename T, typename E, typename Func,
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typename Ret =
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Result<T,
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typename details::ResultErrType<
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typename details::result_of<Func>::type
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>::type
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>
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>
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Ret orElse(const Result<T, E>& result, Func func) {
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return Or::Else<Func>::orElse(result, func);
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}
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struct ok_tag { };
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struct err_tag { };
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template<typename T, typename E>
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struct Storage {
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static constexpr size_t Size = sizeof(T) > sizeof(E) ? sizeof(T) : sizeof(E);
|
|
static constexpr size_t Align = sizeof(T) > sizeof(E) ? alignof(T) : alignof(E);
|
|
|
|
typedef typename std::aligned_storage<Size, Align>::type type;
|
|
|
|
Storage()
|
|
: initialized_(false)
|
|
{ }
|
|
|
|
void construct(types::Ok<T> ok)
|
|
{
|
|
new (&storage_) T(std::move(ok.val));
|
|
initialized_ = true;
|
|
}
|
|
void construct(types::Err<E> err)
|
|
{
|
|
new (&storage_) E(err.val);
|
|
initialized_ = true;
|
|
}
|
|
|
|
template<typename U>
|
|
void rawConstruct(U&& val) {
|
|
typedef typename std::decay<U>::type CleanU;
|
|
|
|
new (&storage_) CleanU(std::forward<U>(val));
|
|
initialized_ = true;
|
|
}
|
|
|
|
template<typename U>
|
|
const U& get() const {
|
|
return *reinterpret_cast<const U *>(&storage_);
|
|
}
|
|
|
|
template<typename U>
|
|
U& get() {
|
|
return *reinterpret_cast<U *>(&storage_);
|
|
}
|
|
|
|
void destroy(ok_tag) {
|
|
if (initialized_) {
|
|
get<T>().~T();
|
|
initialized_ = false;
|
|
}
|
|
}
|
|
|
|
void destroy(err_tag) {
|
|
if (initialized_) {
|
|
get<E>().~E();
|
|
initialized_ = false;
|
|
}
|
|
}
|
|
|
|
type storage_;
|
|
bool initialized_;
|
|
};
|
|
|
|
template<typename E>
|
|
struct Storage<void, E> {
|
|
typedef typename std::aligned_storage<sizeof(E), alignof(E)>::type type;
|
|
|
|
void construct(types::Ok<void>)
|
|
{
|
|
initialized_ = true;
|
|
}
|
|
|
|
void construct(types::Err<E> err)
|
|
{
|
|
new (&storage_) E(err.val);
|
|
initialized_ = true;
|
|
}
|
|
|
|
template<typename U>
|
|
void rawConstruct(U&& val) {
|
|
typedef typename std::decay<U>::type CleanU;
|
|
|
|
new (&storage_) CleanU(std::forward<U>(val));
|
|
initialized_ = true;
|
|
}
|
|
|
|
void destroy(ok_tag) { initialized_ = false; }
|
|
void destroy(err_tag) {
|
|
if (initialized_) {
|
|
get<E>().~E(); initialized_ = false;
|
|
}
|
|
}
|
|
|
|
template<typename U,
|
|
typename = std::enable_if_t<!std::is_same<U, void>::value>>
|
|
const U& get() const {
|
|
return *reinterpret_cast<const U *>(&storage_);
|
|
}
|
|
|
|
template<typename U,
|
|
typename = std::enable_if_t<!std::is_same<U, void>::value>>
|
|
typename std::add_lvalue_reference<U>::type get() {
|
|
return *reinterpret_cast<U *>(&storage_);
|
|
}
|
|
|
|
template<typename U,
|
|
typename = std::enable_if_t<std::is_same<U, void>::value>>
|
|
void get() {}
|
|
|
|
type storage_;
|
|
bool initialized_;
|
|
};
|
|
|
|
template<typename T, typename E>
|
|
struct Constructor {
|
|
|
|
static void move(Storage<T, E>&& src, Storage<T, E>& dst, ok_tag) {
|
|
dst.rawConstruct(std::move(src.template get<T>()));
|
|
src.destroy(ok_tag());
|
|
}
|
|
|
|
static void copy(const Storage<T, E>& src, Storage<T, E>& dst, ok_tag) {
|
|
dst.rawConstruct(src.template get<T>());
|
|
}
|
|
|
|
static void move(Storage<T, E>&& src, Storage<T, E>& dst, err_tag) {
|
|
dst.rawConstruct(std::move(src.template get<E>()));
|
|
src.destroy(err_tag());
|
|
}
|
|
|
|
static void copy(const Storage<T, E>& src, Storage<T, E>& dst, err_tag) {
|
|
dst.rawConstruct(src.template get<E>());
|
|
}
|
|
};
|
|
|
|
template<typename E>
|
|
struct Constructor<void, E> {
|
|
static void move(Storage<void, E>&& src, Storage<void, E>& dst, ok_tag) {
|
|
}
|
|
|
|
static void copy(const Storage<void, E>& src, Storage<void, E>& dst, ok_tag) {
|
|
}
|
|
|
|
static void move(Storage<void, E>&& src, Storage<void, E>& dst, err_tag) {
|
|
dst.rawConstruct(std::move(src.template get<E>()));
|
|
src.destroy(err_tag());
|
|
}
|
|
|
|
static void copy(const Storage<void, E>& src, Storage<void, E>& dst, err_tag) {
|
|
dst.rawConstruct(src.template get<E>());
|
|
}
|
|
};
|
|
|
|
} // namespace details
|
|
|
|
namespace concept {
|
|
|
|
template<typename T, typename = void> struct EqualityComparable : std::false_type { };
|
|
|
|
template<typename T>
|
|
struct EqualityComparable<T,
|
|
typename std::enable_if<
|
|
true,
|
|
typename details::void_t<decltype(std::declval<T>() == std::declval<T>())>::type
|
|
>::type
|
|
> : std::true_type
|
|
{
|
|
};
|
|
|
|
|
|
} // namespace concept
|
|
|
|
template<typename T, typename E>
|
|
struct Result {
|
|
|
|
static_assert(!std::is_same<E, void>::value, "void error type is not allowed");
|
|
|
|
typedef details::Storage<T, E> storage_type;
|
|
|
|
Result(types::Ok<T> ok)
|
|
: ok_(true)
|
|
{
|
|
storage_.construct(std::move(ok));
|
|
}
|
|
|
|
Result(types::Err<E> err)
|
|
: ok_(false)
|
|
{
|
|
storage_.construct(std::move(err));
|
|
}
|
|
|
|
Result(Result&& other) {
|
|
if (other.isOk()) {
|
|
details::Constructor<T, E>::move(std::move(other.storage_), storage_, details::ok_tag());
|
|
ok_ = true;
|
|
} else {
|
|
details::Constructor<T, E>::move(std::move(other.storage_), storage_, details::err_tag());
|
|
ok_ = false;
|
|
}
|
|
}
|
|
|
|
Result(const Result& other) {
|
|
if (other.isOk()) {
|
|
details::Constructor<T, E>::copy(other.storage_, storage_, details::ok_tag());
|
|
ok_ = true;
|
|
} else {
|
|
details::Constructor<T, E>::copy(other.storage_, storage_, details::err_tag());
|
|
ok_ = false;
|
|
}
|
|
}
|
|
|
|
~Result() {
|
|
if (ok_)
|
|
storage_.destroy(details::ok_tag());
|
|
else
|
|
storage_.destroy(details::err_tag());
|
|
}
|
|
|
|
bool isOk() const {
|
|
return ok_;
|
|
}
|
|
|
|
bool isErr() const {
|
|
return !ok_;
|
|
}
|
|
|
|
T expect(const char* str)
|
|
{
|
|
if (!isOk()) {
|
|
::fprintf(stderr, "%s\n", str);
|
|
abort();
|
|
}
|
|
return expect_impl(std::is_same<T, void>());
|
|
}
|
|
|
|
template<typename Func>
|
|
auto map(Func func)
|
|
{
|
|
using return_type = decltype(func(T{}));
|
|
|
|
if (this->isOk()) {
|
|
auto value = std::move(this->storage().template get<T>());
|
|
auto res = func(std::move(value));
|
|
return Result<return_type, E>(
|
|
types::Ok<return_type>(std::move(res)));
|
|
}
|
|
|
|
return Result<return_type, E>(
|
|
types::Err<E>(this->storage().template get<E>()));
|
|
}
|
|
|
|
template<typename Func,
|
|
typename Ret =
|
|
Result<T,
|
|
typename details::ResultErrType<
|
|
typename details::result_of<Func>::type
|
|
>::type
|
|
>
|
|
>
|
|
Ret mapError(Func func) const {
|
|
return details::mapError(*this, func);
|
|
}
|
|
|
|
template<typename Func>
|
|
Result<void, E> then(Func func) {
|
|
if (this->isOk()) {
|
|
func(std::move(this->storage().template get<T>()));
|
|
|
|
return Ok();
|
|
}
|
|
|
|
return Err(std::move(this->storage().template get<E>()));
|
|
}
|
|
|
|
template<typename Func>
|
|
Result<typename std::result_of<Func>::type, E> then(Func func) {
|
|
if (this->isOk()) {
|
|
return Ok(func(std::move(this->storage().template get<T>())));
|
|
}
|
|
|
|
return Err(std::move(this->storage().template get<E>()));
|
|
}
|
|
|
|
template<typename Func>
|
|
void otherwise(Func func) {
|
|
if (this->isOk()) {
|
|
return;
|
|
}
|
|
|
|
func(std::move(this->storage().template get<E>()));
|
|
}
|
|
|
|
template<typename Func,
|
|
typename Ret =
|
|
Result<T,
|
|
typename details::ResultErrType<
|
|
typename details::result_of<Func>::type
|
|
>::type
|
|
>
|
|
>
|
|
Ret orElse(Func func) const {
|
|
return details::orElse(*this, func);
|
|
}
|
|
|
|
storage_type& storage() {
|
|
return storage_;
|
|
}
|
|
|
|
const storage_type& storage() const {
|
|
return storage_;
|
|
}
|
|
|
|
template<typename U = T>
|
|
typename std::enable_if<
|
|
!std::is_same<U, void>::value,
|
|
T
|
|
>::type
|
|
unwrapOr(const U& defaultValue) const {
|
|
if (isOk()) {
|
|
return storage().template get<T>();
|
|
}
|
|
return defaultValue;
|
|
}
|
|
|
|
template<typename Func>
|
|
auto unwrapOrElse(Func func) const {
|
|
if (isOk()) {
|
|
return storage().template get<T>();
|
|
}
|
|
return func(this->storage().template get<E>());
|
|
}
|
|
|
|
template<typename U = T>
|
|
typename std::enable_if<
|
|
!std::is_same<U, void>::value,
|
|
U
|
|
>::type
|
|
unwrap() const {
|
|
if (isOk()) {
|
|
return std::move(storage().template get<U>());
|
|
}
|
|
|
|
::fprintf(stderr, "Attempting to unwrap an error Result\n");
|
|
abort();
|
|
}
|
|
|
|
template<typename U = T>
|
|
typename std::enable_if<
|
|
!std::is_same<U, void>::value,
|
|
U
|
|
>::type
|
|
unwrap() {
|
|
if (isOk()) {
|
|
return std::move(storage().template get<U>());
|
|
}
|
|
|
|
::fprintf(stderr, "Attempting to unwrap an error Result\n");
|
|
abort();
|
|
}
|
|
|
|
template<typename U = T>
|
|
typename std::enable_if<std::is_same<U, void>::value, U>::type unwrap()
|
|
const
|
|
{
|
|
if (isOk()) {
|
|
return;
|
|
}
|
|
|
|
::fprintf(stderr, "Attempting to unwrap an error Result\n");
|
|
abort();
|
|
}
|
|
|
|
E unwrapErr() const
|
|
{
|
|
if (isErr()) {
|
|
return storage().template get<E>();
|
|
}
|
|
|
|
::fprintf(stderr, "Attempting to unwrapErr an ok Result\n");
|
|
abort();
|
|
}
|
|
|
|
private:
|
|
T expect_impl(std::true_type) const {}
|
|
T expect_impl(std::false_type)
|
|
{
|
|
return std::move(storage_.template get<T>());
|
|
}
|
|
|
|
bool ok_;
|
|
storage_type storage_;
|
|
};
|
|
|
|
template<typename T, typename E>
|
|
bool operator==(const Result<T, E>& lhs, const Result<T, E>& rhs) {
|
|
static_assert(concept::EqualityComparable<T>::value, "T must be EqualityComparable for Result to be comparable");
|
|
static_assert(concept::EqualityComparable<E>::value, "E must be EqualityComparable for Result to be comparable");
|
|
|
|
if (lhs.isOk() && rhs.isOk()) {
|
|
return lhs.storage().template get<T>() == rhs.storage().template get<T>();
|
|
}
|
|
if (lhs.isErr() && rhs.isErr()) {
|
|
return lhs.storage().template get<E>() == rhs.storage().template get<E>();
|
|
}
|
|
}
|
|
|
|
template<typename T, typename E>
|
|
bool operator==(const Result<T, E>& lhs, types::Ok<T> ok) {
|
|
static_assert(concept::EqualityComparable<T>::value, "T must be EqualityComparable for Result to be comparable");
|
|
|
|
if (!lhs.isOk()) return false;
|
|
|
|
return lhs.storage().template get<T>() == ok.val;
|
|
}
|
|
|
|
template<typename E>
|
|
bool operator==(const Result<void, E>& lhs, types::Ok<void>) {
|
|
return lhs.isOk();
|
|
}
|
|
|
|
template<typename T, typename E>
|
|
bool operator==(const Result<T, E>& lhs, types::Err<E> err) {
|
|
static_assert(concept::EqualityComparable<E>::value, "E must be EqualityComparable for Result to be comparable");
|
|
if (!lhs.isErr()) return false;
|
|
|
|
return lhs.storage().template get<E>() == err.val;
|
|
}
|
|
|
|
#define TRY(...) \
|
|
({ \
|
|
auto res = __VA_ARGS__; \
|
|
if (!res.isOk()) { \
|
|
typedef typename ::details::ResultErrType<decltype(res)>::type E; \
|
|
return ::types::Err<E>(res.storage().template get<E>()); \
|
|
} \
|
|
res.unwrap(); \
|
|
})
|