124 lines
3.8 KiB
C++
124 lines
3.8 KiB
C++
/* -*- C++ -*-
|
|
* Serene Programming Language
|
|
*
|
|
* Copyright (c) 2019-2021 Sameer Rahmani <lxsameer@gnu.org>
|
|
*
|
|
* 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, version 2.
|
|
*
|
|
* 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/>.
|
|
*/
|
|
|
|
#ifndef SERENE_UTILS_H
|
|
#define SERENE_UTILS_H
|
|
|
|
#include "serene/export.h"
|
|
|
|
#include <llvm/Support/Error.h>
|
|
#include <variant>
|
|
|
|
// Sometimes we need this to make both analyzer happy
|
|
// and the fn signature right.
|
|
#define UNUSED(x) (void)(x)
|
|
|
|
// C++17 required. We can't go back to 14 any more :))
|
|
|
|
namespace serene {
|
|
|
|
/// A similar type to Rust's Result data structure. It either holds a value of
|
|
/// type `T` successfully or holds a value of type `E` errorfully. It is
|
|
/// designed to be used in situations which the return value of a function might
|
|
/// contains some errors. The official way to use this type is to use the
|
|
/// factory functions `Success` and `Error`. For example:
|
|
///
|
|
/// \code
|
|
/// auto successfulResult = Result<int>::success(3);
|
|
/// auto notOkResult = Result<int>::error(SomeLLVMError());
|
|
// \endcode
|
|
///
|
|
/// In order check for a value being errorful or successful checkout the `ok`
|
|
/// method or simply use the value as a conditiona.
|
|
template <typename T, typename E = llvm::Error>
|
|
class SERENE_EXPORT Result {
|
|
|
|
// The actual data container
|
|
std::variant<T, E> contents;
|
|
|
|
/// The main constructor which we made private to avoid ambiguousness in
|
|
/// input type. `Success` and `Error` call this ctor.
|
|
template <typename InPlace, typename Content>
|
|
Result(InPlace i, Content &&c) : contents(i, std::forward<Content>(c)){};
|
|
|
|
public:
|
|
/// Create a succesfull result with the given value of type `T`.
|
|
static Result success(T v) {
|
|
return Result(std::in_place_index_t<0>(), std::move(v));
|
|
}
|
|
|
|
/// Create an errorful result with the given value of type `E` (default
|
|
/// `llvm::Error`).
|
|
static Result error(E e) {
|
|
return Result(std::in_place_index_t<1>(), std::move(e));
|
|
}
|
|
|
|
/// Return the value if it's successful otherwise throw an error
|
|
T &&getValue() && { return std::move(std::get<0>(contents)); };
|
|
|
|
/// Return the error value if it's errorful otherwise throw an error
|
|
E &&getError() && { return std::move(std::get<1>(contents)); };
|
|
|
|
// using std::get, it'll throw if contents doesn't contain what you ask for
|
|
|
|
/// Return the value if it's successful otherwise throw an error
|
|
T &getValue() & { return std::get<0>(contents); };
|
|
|
|
/// Return the error value if it's errorful otherwise throw an error
|
|
E &getError() & { return std::get<1>(contents); };
|
|
|
|
const T &getValue() const & { return std::get<0>(contents); }
|
|
const E &getError() const & { return std::get<1>(contents); }
|
|
|
|
/// Return the a boolean value indicating whether the value is succesful
|
|
/// or errorful.
|
|
bool ok() const { return std::holds_alternative<T>(contents); };
|
|
|
|
operator bool() const { return ok(); }
|
|
|
|
const T &getValueOrFail(llvm::StringRef msg, int exitCode = 1) const & {
|
|
if (ok()) {
|
|
return getValue();
|
|
}
|
|
|
|
llvm::errs() << msg << "\n";
|
|
exit(exitCode);
|
|
}
|
|
|
|
T &getValueOrFail(llvm::StringRef msg, int exitCode = 1) & {
|
|
if (ok()) {
|
|
return getValue();
|
|
}
|
|
|
|
llvm::errs() << msg << "\n";
|
|
exit(exitCode);
|
|
}
|
|
|
|
T &&getValueOrFail(llvm::StringRef msg, int exitCode = 1) && {
|
|
if (ok()) {
|
|
return std::move(getValue());
|
|
}
|
|
|
|
llvm::errs() << msg << "\n";
|
|
exit(exitCode);
|
|
}
|
|
};
|
|
|
|
} // namespace serene
|
|
#endif
|