diff options
Diffstat (limited to 'src/compat')
-rw-r--r-- | src/compat/result.hpp | 78 | ||||
-rw-r--r-- | src/compat/result_test.cpp | 79 |
2 files changed, 157 insertions, 0 deletions
diff --git a/src/compat/result.hpp b/src/compat/result.hpp new file mode 100644 index 0000000..f03c026 --- /dev/null +++ b/src/compat/result.hpp @@ -0,0 +1,78 @@ +#pragma once +// result.hpp - A possibly failed return value +// +// Copyright © 2014 Ben Longbons <b.r.longbons@gmail.com> +// +// This file is part of The Mana World (Athena server) +// +// This program is free software: you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation, either version 3 of the License, or +// (at your option) any later version. +// +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License +// along with this program. If not, see <http://www.gnu.org/licenses/>. + +#include "fwd.hpp" + +#include "../strings/rstring.hpp" + +#include "option.hpp" + +namespace tmwa +{ + namespace result + { + enum ResultMagicFlag { magic_flag }; + + template<class T> + class Result + { + Option<T> success; + RString failure; + public: + Result(ResultMagicFlag, T v) + : success(Some(std::move(v))), failure() + {} + Result(ResultMagicFlag, RString msg) + : success(None), failure(std::move(msg)) + {} + + bool is_ok() { return success.is_some(); } + bool is_err() { return !is_ok(); } + + Option<T>& get_success() { return success; } + RString& get_failure() { return failure; } + }; + + template<class T> + Result<T> Ok(T v) + { + return Result<T>(magic_flag, std::move(v)); + } + + struct Err + { + RString message; + Err(RString m) : message(std::move(m)) {} + + template<class T> + operator Result<T>() + { + return Result<T>(magic_flag, message); + } + }; + } // namespace result + using result::Result; + using result::Ok; + using result::Err; + +#define TRY(r) ({ auto _res = r; TRY_UNWRAP(_res.get_success(), return ::tmwa::Err(_res.get_failure())); }) + // TODO the existence of this as a separate macro is a bug. +#define TRY_MOVE(r) ({ auto _res = r; TRY_UNWRAP(std::move(_res.get_success()), return ::tmwa::Err(_res.get_failure())); }) +} // namespace tmwa diff --git a/src/compat/result_test.cpp b/src/compat/result_test.cpp new file mode 100644 index 0000000..0fcc181 --- /dev/null +++ b/src/compat/result_test.cpp @@ -0,0 +1,79 @@ +#include "result.hpp" +// result_test.cpp - Testsuite for possibly failing return values +// +// Copyright © 2014 Ben Longbons <b.r.longbons@gmail.com> +// +// This file is part of The Mana World (Athena server) +// +// This program is free software: you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation, either version 3 of the License, or +// (at your option) any later version. +// +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License +// along with this program. If not, see <http://www.gnu.org/licenses/>. + +#include <gtest/gtest.h> + +#include "../strings/literal.hpp" + +//#include "../poison.hpp" + + +namespace tmwa +{ +TEST(Result, inspect) +{ + struct Foo + { + int val; + + Foo(int v) : val(v) {} + Foo(Foo&&) = default; + Foo(const Foo&) = delete; + Foo& operator = (Foo&&) = default; + Foo& operator = (const Foo&) = delete; + + bool operator == (const Foo& other) const + { + return this->val == other.val; + } + }; + + Result<Foo> foo = Ok(Foo(1)); + EXPECT_TRUE(foo.is_ok()); + EXPECT_FALSE(foo.is_err()); + EXPECT_EQ(foo.get_success(), Some(Foo(1))); + EXPECT_EQ(foo.get_failure(), ""_s); + foo = Err("oops"_s); + EXPECT_FALSE(foo.is_ok()); + EXPECT_TRUE(foo.is_err()); + EXPECT_EQ(foo.get_success(), None<Foo>()); + EXPECT_EQ(foo.get_failure(), "oops"_s); +} + +static +Result<int> try_you(bool b) +{ + return b ? Ok(0) : Err("die"_s); +} + +static +Result<int> try_me(bool b) +{ + return Ok(TRY(try_you(b)) + 1); +} + +TEST(Result, try) +{ + Result<int> t = try_me(true); + EXPECT_EQ(t.get_success(), Some(1)); + Result<int> f = try_me(false); + EXPECT_EQ(f.get_failure(), "die"_s); +} +} // namespace tmwa |