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result: Add [[nodiscard]] specifiers where applicable

The result code classes are used quite extensively throughout both the
kernel and service HLE code. We can mark these member functions as
[[nodiscard]] to prevent a few logic bugs from slipping through.
This commit is contained in:
Lioncash 2021-06-05 06:05:39 -04:00
parent fefc76e5da
commit 25b73e135f

View file

@ -124,21 +124,21 @@ union ResultCode {
constexpr ResultCode(ErrorModule module_, u32 description_) constexpr ResultCode(ErrorModule module_, u32 description_)
: raw(module.FormatValue(module_) | description.FormatValue(description_)) {} : raw(module.FormatValue(module_) | description.FormatValue(description_)) {}
constexpr bool IsSuccess() const { [[nodiscard]] constexpr bool IsSuccess() const {
return raw == 0; return raw == 0;
} }
constexpr bool IsError() const { [[nodiscard]] constexpr bool IsError() const {
return raw != 0; return !IsSuccess();
} }
}; };
constexpr bool operator==(const ResultCode& a, const ResultCode& b) { [[nodiscard]] constexpr bool operator==(const ResultCode& a, const ResultCode& b) {
return a.raw == b.raw; return a.raw == b.raw;
} }
constexpr bool operator!=(const ResultCode& a, const ResultCode& b) { [[nodiscard]] constexpr bool operator!=(const ResultCode& a, const ResultCode& b) {
return a.raw != b.raw; return !operator==(a, b);
} }
// Convenience functions for creating some common kinds of errors: // Convenience functions for creating some common kinds of errors:
@ -200,7 +200,7 @@ public:
* specify the success code. `success_code` must not be an error code. * specify the success code. `success_code` must not be an error code.
*/ */
template <typename... Args> template <typename... Args>
static ResultVal WithCode(ResultCode success_code, Args&&... args) { [[nodiscard]] static ResultVal WithCode(ResultCode success_code, Args&&... args) {
ResultVal<T> result; ResultVal<T> result;
result.emplace(success_code, std::forward<Args>(args)...); result.emplace(success_code, std::forward<Args>(args)...);
return result; return result;
@ -259,49 +259,49 @@ public:
} }
/// Returns true if the `ResultVal` contains an error code and no value. /// Returns true if the `ResultVal` contains an error code and no value.
bool empty() const { [[nodiscard]] bool empty() const {
return result_code.IsError(); return result_code.IsError();
} }
/// Returns true if the `ResultVal` contains a return value. /// Returns true if the `ResultVal` contains a return value.
bool Succeeded() const { [[nodiscard]] bool Succeeded() const {
return result_code.IsSuccess(); return result_code.IsSuccess();
} }
/// Returns true if the `ResultVal` contains an error code and no value. /// Returns true if the `ResultVal` contains an error code and no value.
bool Failed() const { [[nodiscard]] bool Failed() const {
return empty(); return empty();
} }
ResultCode Code() const { [[nodiscard]] ResultCode Code() const {
return result_code; return result_code;
} }
const T& operator*() const { [[nodiscard]] const T& operator*() const {
return object; return object;
} }
T& operator*() { [[nodiscard]] T& operator*() {
return object; return object;
} }
const T* operator->() const { [[nodiscard]] const T* operator->() const {
return &object; return &object;
} }
T* operator->() { [[nodiscard]] T* operator->() {
return &object; return &object;
} }
/// Returns the value contained in this `ResultVal`, or the supplied default if it is missing. /// Returns the value contained in this `ResultVal`, or the supplied default if it is missing.
template <typename U> template <typename U>
T ValueOr(U&& value) const { [[nodiscard]] T ValueOr(U&& value) const {
return !empty() ? object : std::move(value); return !empty() ? object : std::move(value);
} }
/// Asserts that the result succeeded and returns a reference to it. /// Asserts that the result succeeded and returns a reference to it.
T& Unwrap() & { [[nodiscard]] T& Unwrap() & {
ASSERT_MSG(Succeeded(), "Tried to Unwrap empty ResultVal"); ASSERT_MSG(Succeeded(), "Tried to Unwrap empty ResultVal");
return **this; return **this;
} }
T&& Unwrap() && { [[nodiscard]] T&& Unwrap() && {
ASSERT_MSG(Succeeded(), "Tried to Unwrap empty ResultVal"); ASSERT_MSG(Succeeded(), "Tried to Unwrap empty ResultVal");
return std::move(**this); return std::move(**this);
} }
@ -320,7 +320,7 @@ private:
* `T` with and creates a success `ResultVal` contained the constructed value. * `T` with and creates a success `ResultVal` contained the constructed value.
*/ */
template <typename T, typename... Args> template <typename T, typename... Args>
ResultVal<T> MakeResult(Args&&... args) { [[nodiscard]] ResultVal<T> MakeResult(Args&&... args) {
return ResultVal<T>::WithCode(ResultSuccess, std::forward<Args>(args)...); return ResultVal<T>::WithCode(ResultSuccess, std::forward<Args>(args)...);
} }
@ -329,7 +329,7 @@ ResultVal<T> MakeResult(Args&&... args) {
* copy or move constructing. * copy or move constructing.
*/ */
template <typename Arg> template <typename Arg>
ResultVal<std::remove_reference_t<Arg>> MakeResult(Arg&& arg) { [[nodiscard]] ResultVal<std::remove_reference_t<Arg>> MakeResult(Arg&& arg) {
return ResultVal<std::remove_reference_t<Arg>>::WithCode(ResultSuccess, std::forward<Arg>(arg)); return ResultVal<std::remove_reference_t<Arg>>::WithCode(ResultSuccess, std::forward<Arg>(arg));
} }