mirror of
https://github.com/ToruNiina/toml11.git
synced 2025-09-17 09:08:08 +08:00
add result<T, E> struct to handle errors
aiming later updates and refactoring of parsers
This commit is contained in:
ToruNiina
414
toml/result.hpp
Normal file
414
toml/result.hpp
Normal file
@@ -0,0 +1,414 @@
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#ifndef TOML11_RESULT_H
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#define TOML11_RESULT_H
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#include <type_traits>
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#include <utility>
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#include <new>
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#include <cassert>
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namespace toml
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{
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template<typename T>
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struct success
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{
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using value_type = T;
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value_type value;
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explicit success(const value_type& v)
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noexcept(std::is_nothrow_copy_constructible<value_type>::value)
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: value(v)
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{}
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explicit success(value_type&& v)
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noexcept(std::is_nothrow_move_constructible<value_type>::value)
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: value(std::move(v))
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{}
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template<typename U>
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explicit success(U&& v): value(std::forward<U>(v)) {}
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template<typename U>
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explicit success(const success<U>& v): value(v.value) {}
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template<typename U>
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explicit success(success<U>&& v): value(std::move(v.value)) {}
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~success() = default;
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success(const success&) = default;
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success(success&&) = default;
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success& operator=(const success&) = default;
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success& operator=(success&&) = default;
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};
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template<typename T>
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struct failure
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{
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using value_type = T;
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value_type value;
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explicit failure(const value_type& v)
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noexcept(std::is_nothrow_copy_constructible<value_type>::value)
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: value(v)
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{}
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explicit failure(value_type&& v)
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noexcept(std::is_nothrow_move_constructible<value_type>::value)
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: value(std::move(v))
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{}
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template<typename U>
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explicit failure(U&& v): value(std::forward<U>(v)) {}
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template<typename U>
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explicit failure(const failure<U>& v): value(v.value) {}
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template<typename U>
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explicit failure(failure<U>&& v): value(std::move(v.value)) {}
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~failure() = default;
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failure(const failure&) = default;
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failure(failure&&) = default;
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failure& operator=(const failure&) = default;
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failure& operator=(failure&&) = default;
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};
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template<typename T>
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success<typename std::remove_cv<typename std::remove_reference<T>::type>::type>
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ok(T&& v)
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{
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return success<
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typename std::remove_cv<typename std::remove_reference<T>::type>::type
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>(std::forward<T>(v));
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}
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template<typename T>
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failure<typename std::remove_cv<typename std::remove_reference<T>::type>::type>
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err(T&& v)
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{
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return failure<
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typename std::remove_cv<typename std::remove_reference<T>::type>::type
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>(std::forward<T>(v));
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}
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inline success<std::string> ok(const char* literal)
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{
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return success<std::string>(std::string(literal));
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}
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inline failure<std::string> err(const char* literal)
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{
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return failure<std::string>(std::string(literal));
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}
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template<typename T, typename E>
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struct result
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{
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using value_type = T;
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using error_type = E;
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using success_type = success<value_type>;
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using failure_type = failure<error_type>;
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result(const success_type& s): is_ok_(true)
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{
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auto tmp = ::new(std::addressof(this->succ)) success_type(s);
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assert(tmp == std::addressof(this->succ));
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}
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result(const failure_type& f): is_ok_(false)
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{
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auto tmp = ::new(std::addressof(this->fail)) failure_type(f);
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assert(tmp == std::addressof(this->fail));
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}
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result(success_type&& s): is_ok_(true)
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{
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auto tmp = ::new(std::addressof(this->succ)) success_type(std::move(s));
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assert(tmp == std::addressof(this->succ));
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}
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result(failure_type&& f): is_ok_(false)
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{
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auto tmp = ::new(std::addressof(this->fail)) failure_type(std::move(f));
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assert(tmp == std::addressof(this->fail));
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}
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template<typename U>
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result(const success<U>& s): is_ok_(true)
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{
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auto tmp = ::new(std::addressof(this->succ)) success_type(s.value);
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assert(tmp == std::addressof(this->succ));
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}
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template<typename U>
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result(const failure<U>& f): is_ok_(false)
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{
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auto tmp = ::new(std::addressof(this->fail)) failure_type(f.value);
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assert(tmp == std::addressof(this->fail));
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}
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template<typename U>
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result(success<U>&& s): is_ok_(true)
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{
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auto tmp = ::new(std::addressof(this->succ)) success_type(std::move(s.value));
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assert(tmp == std::addressof(this->succ));
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}
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template<typename U>
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result(failure<U>&& f): is_ok_(false)
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{
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auto tmp = ::new(std::addressof(this->fail)) failure_type(std::move(f.value));
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assert(tmp == std::addressof(this->fail));
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}
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result& operator=(const success_type& s)
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{
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this->cleanup();
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this->is_ok_ = true;
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auto tmp = ::new(std::addressof(this->succ)) success_type(s);
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assert(tmp == std::addressof(this->succ));
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return *this;
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}
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result& operator=(const failure_type& f)
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{
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this->cleanup();
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this->is_ok_ = false;
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auto tmp = ::new(std::addressof(this->fail)) failure_type(f);
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assert(tmp == std::addressof(this->fail));
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return *this;
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}
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result& operator=(success_type&& s)
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{
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this->cleanup();
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this->is_ok_ = true;
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auto tmp = ::new(std::addressof(this->succ)) success_type(std::move(s));
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assert(tmp == std::addressof(this->succ));
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return *this;
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}
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result& operator=(failure_type&& f)
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{
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this->cleanup();
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this->is_ok_ = false;
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auto tmp = ::new(std::addressof(this->fail)) failure_type(std::move(f));
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assert(tmp == std::addressof(this->fail));
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return *this;
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}
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template<typename U>
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result& operator=(const success<U>& s)
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{
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this->cleanup();
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this->is_ok_ = true;
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auto tmp = ::new(std::addressof(this->succ)) success_type(s.value);
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assert(tmp == std::addressof(this->succ));
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return *this;
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}
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template<typename U>
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result& operator=(const failure<U>& f)
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{
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this->cleanup();
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this->is_ok_ = false;
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auto tmp = ::new(std::addressof(this->fail)) failure_type(f.value);
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assert(tmp == std::addressof(this->fail));
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return *this;
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}
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template<typename U>
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result& operator=(success<U>&& s)
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{
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this->cleanup();
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this->is_ok_ = true;
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auto tmp = ::new(std::addressof(this->succ)) success_type(std::move(s.value));
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assert(tmp == std::addressof(this->succ));
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return *this;
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}
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template<typename U>
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result& operator=(failure<U>&& f)
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{
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this->cleanup();
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this->is_ok_ = false;
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auto tmp = ::new(std::addressof(this->fail)) failure_type(std::move(f.value));
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assert(tmp == std::addressof(this->fail));
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return *this;
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}
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~result() noexcept {this->cleanup();}
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result(const result& other): is_ok_(other.is_ok())
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{
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if(other.is_ok())
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{
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auto tmp = ::new(std::addressof(this->succ)) success_type(other.as_ok());
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assert(tmp == std::addressof(this->succ));
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}
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else
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{
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auto tmp = ::new(std::addressof(this->fail)) failure_type(other.as_err());
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assert(tmp == std::addressof(this->fail));
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}
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}
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result(result&& other): is_ok_(other.is_ok())
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{
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if(other.is_ok())
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{
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auto tmp = ::new(std::addressof(this->succ)) success_type(other.as_ok());
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assert(tmp == std::addressof(this->succ));
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}
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else
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{
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auto tmp = ::new(std::addressof(this->fail)) failure_type(other.as_err());
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assert(tmp == std::addressof(this->fail));
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}
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}
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template<typename U, typename F>
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result(const result<U, F>& other): is_ok_(other.is_ok())
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{
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if(other.is_ok())
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{
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auto tmp = ::new(std::addressof(this->succ)) success_type(other.as_ok());
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assert(tmp == std::addressof(this->succ));
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}
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else
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{
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auto tmp = ::new(std::addressof(this->fail)) failure_type(other.as_err());
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assert(tmp == std::addressof(this->fail));
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}
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}
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template<typename U, typename F>
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result(result<U, F>&& other): is_ok_(other.is_ok())
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{
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if(other.is_ok())
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{
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auto tmp = ::new(std::addressof(this->succ)) success_type(other.as_ok());
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assert(tmp == std::addressof(this->succ));
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}
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else
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{
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auto tmp = ::new(std::addressof(this->fail)) failure_type(other.as_err());
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assert(tmp == std::addressof(this->fail));
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}
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}
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result& operator=(const result& other)
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{
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this->cleanup();
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if(other.is_ok())
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{
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auto tmp = ::new(std::addressof(this->succ)) success_type(other.as_ok());
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assert(tmp == std::addressof(this->succ));
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}
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else
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{
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auto tmp = ::new(std::addressof(this->fail)) failure_type(other.as_err());
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assert(tmp == std::addressof(this->fail));
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}
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is_ok_ = other.is_ok();
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return *this;
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}
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result& operator=(result&& other)
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{
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this->cleanup();
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if(other.is_ok())
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{
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auto tmp = ::new(std::addressof(this->succ)) success_type(std::move(other.as_ok()));
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assert(tmp == std::addressof(this->succ));
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}
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else
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{
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auto tmp = ::new(std::addressof(this->fail)) failure_type(std::move(other.as_err()));
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assert(tmp == std::addressof(this->fail));
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}
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is_ok_ = other.is_ok();
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return *this;
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}
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template<typename U, typename F>
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result& operator=(const result<U, F>& other)
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{
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this->cleanup();
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if(other.is_ok())
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{
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auto tmp = ::new(std::addressof(this->succ)) success_type(other.as_ok());
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assert(tmp == std::addressof(this->succ));
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}
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else
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{
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auto tmp = ::new(std::addressof(this->fail)) failure_type(other.as_err());
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assert(tmp == std::addressof(this->fail));
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}
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is_ok_ = other.is_ok();
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return *this;
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}
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template<typename U, typename F>
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result& operator=(result<U, F>&& other)
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{
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this->cleanup();
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if(other.is_ok())
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{
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auto tmp = ::new(std::addressof(this->succ)) success_type(std::move(other.as_ok()));
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assert(tmp == std::addressof(this->succ));
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}
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else
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{
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auto tmp = ::new(std::addressof(this->fail)) failure_type(std::move(other.as_err()));
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assert(tmp == std::addressof(this->fail));
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}
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is_ok_ = other.is_ok();
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return *this;
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}
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bool is_ok() const noexcept {return is_ok_;}
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bool is_err() const noexcept {return !is_ok_;}
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operator bool() const noexcept {return is_ok_;}
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value_type& unwrap() &
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{
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if(is_err()) {throw std::runtime_error("result: bad unwrap");}
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return this->succ.value;
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}
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value_type const& unwrap() const&
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{
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if(is_err()) {throw std::runtime_error("result: bad unwrap");}
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return this->succ.value;
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}
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value_type&& unwrap() &&
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{
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if(is_err()) {throw std::runtime_error("result: bad unwrap");}
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return std::move(this->succ.value);
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}
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error_type& unwrap_err() &
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{
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if(is_ok()) {throw std::runtime_error("result: bad unwrap_err");}
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return this->fail.value;
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}
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error_type const& unwrap_err() const&
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{
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if(is_ok()) {throw std::runtime_error("result: bad unwrap_err");}
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return this->fail.value;
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}
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error_type&& unwrap_err() &&
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{
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if(is_ok()) {throw std::runtime_error("result: bad unwrap_err");}
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return std::move(this->fail.value);
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}
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value_type& as_ok() & noexcept {return this->succ.value;}
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value_type const& as_ok() const& noexcept {return this->succ.value;}
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value_type&& as_ok() && noexcept {return std::move(this->succ.value);}
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error_type& as_err() & noexcept {return this->fail.value;}
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error_type const& as_err() const& noexcept {return this->fail.value;}
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error_type&& as_err() && noexcept {return std::move(this->fail.value);}
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private:
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void cleanup() noexcept
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{
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if(this->is_ok_) {this->succ.~success_type();}
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else {this->fail.~failure_type();}
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return;
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}
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private:
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bool is_ok_;
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union
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{
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success_type succ;
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failure_type fail;
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};
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};
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} // toml11
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#endif// TOML11_RESULT_H
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