core: remove ResultVal type

This commit is contained in:
Liam 2023-07-14 20:16:39 -04:00
parent 85e3575496
commit 84cb20bc72
32 changed files with 374 additions and 483 deletions

View file

@ -283,159 +283,6 @@ private:
u32 description_end;
};
/**
* This is an optional value type. It holds a `Result` and, if that code is ResultSuccess, it
* also holds a result of type `T`. If the code is an error code (not ResultSuccess), then trying
* to access the inner value with operator* is undefined behavior and will assert with Unwrap().
* Users of this class must be cognizant to check the status of the ResultVal with operator bool(),
* Code(), Succeeded() or Failed() prior to accessing the inner value.
*
* An example of how it could be used:
* \code
* ResultVal<int> Frobnicate(float strength) {
* if (strength < 0.f || strength > 1.0f) {
* // Can't frobnicate too weakly or too strongly
* return Result{ErrorModule::Common, 1};
* } else {
* // Frobnicated! Give caller a cookie
* return 42;
* }
* }
* \endcode
*
* \code
* auto frob_result = Frobnicate(0.75f);
* if (frob_result) {
* // Frobbed ok
* printf("My cookie is %d\n", *frob_result);
* } else {
* printf("Guess I overdid it. :( Error code: %ux\n", frob_result.Code().raw);
* }
* \endcode
*/
template <typename T>
class ResultVal {
public:
constexpr ResultVal() : expected{} {}
constexpr ResultVal(Result code) : expected{Common::Unexpected(code)} {}
constexpr ResultVal(ResultRange range) : expected{Common::Unexpected(range)} {}
template <typename U>
constexpr ResultVal(U&& val) : expected{std::forward<U>(val)} {}
template <typename... Args>
constexpr ResultVal(Args&&... args) : expected{std::in_place, std::forward<Args>(args)...} {}
~ResultVal() = default;
constexpr ResultVal(const ResultVal&) = default;
constexpr ResultVal(ResultVal&&) = default;
ResultVal& operator=(const ResultVal&) = default;
ResultVal& operator=(ResultVal&&) = default;
[[nodiscard]] constexpr explicit operator bool() const noexcept {
return expected.has_value();
}
[[nodiscard]] constexpr Result Code() const {
return expected.has_value() ? ResultSuccess : expected.error();
}
[[nodiscard]] constexpr bool Succeeded() const {
return expected.has_value();
}
[[nodiscard]] constexpr bool Failed() const {
return !expected.has_value();
}
[[nodiscard]] constexpr T* operator->() {
return std::addressof(expected.value());
}
[[nodiscard]] constexpr const T* operator->() const {
return std::addressof(expected.value());
}
[[nodiscard]] constexpr T& operator*() & {
return *expected;
}
[[nodiscard]] constexpr const T& operator*() const& {
return *expected;
}
[[nodiscard]] constexpr T&& operator*() && {
return *expected;
}
[[nodiscard]] constexpr const T&& operator*() const&& {
return *expected;
}
[[nodiscard]] constexpr T& Unwrap() & {
ASSERT_MSG(Succeeded(), "Tried to Unwrap empty ResultVal");
return expected.value();
}
[[nodiscard]] constexpr const T& Unwrap() const& {
ASSERT_MSG(Succeeded(), "Tried to Unwrap empty ResultVal");
return expected.value();
}
[[nodiscard]] constexpr T&& Unwrap() && {
ASSERT_MSG(Succeeded(), "Tried to Unwrap empty ResultVal");
return std::move(expected.value());
}
[[nodiscard]] constexpr const T&& Unwrap() const&& {
ASSERT_MSG(Succeeded(), "Tried to Unwrap empty ResultVal");
return std::move(expected.value());
}
template <typename U>
[[nodiscard]] constexpr T ValueOr(U&& v) const& {
return expected.value_or(v);
}
template <typename U>
[[nodiscard]] constexpr T ValueOr(U&& v) && {
return expected.value_or(v);
}
private:
// TODO (Morph): Replace this with C++23 std::expected.
Common::Expected<T, Result> expected;
};
/**
* Check for the success of `source` (which must evaluate to a ResultVal). If it succeeds, unwraps
* the contained value and assigns it to `target`, which can be either an l-value expression or a
* variable declaration. If it fails the return code is returned from the current function. Thus it
* can be used to cascade errors out, achieving something akin to exception handling.
*/
#define CASCADE_RESULT(target, source) \
auto CONCAT2(check_result_L, __LINE__) = source; \
if (CONCAT2(check_result_L, __LINE__).Failed()) { \
return CONCAT2(check_result_L, __LINE__).Code(); \
} \
target = std::move(*CONCAT2(check_result_L, __LINE__))
/**
* Analogous to CASCADE_RESULT, but for a bare Result. The code will be propagated if
* non-success, or discarded otherwise.
*/
#define CASCADE_CODE(source) \
do { \
auto CONCAT2(check_result_L, __LINE__) = source; \
if (CONCAT2(check_result_L, __LINE__).IsError()) { \
return CONCAT2(check_result_L, __LINE__); \
} \
} while (false)
#define R_SUCCEEDED(res) (static_cast<Result>(res).IsSuccess())
#define R_FAILED(res) (static_cast<Result>(res).IsFailure())