summaryrefslogtreecommitdiffstats
path: root/src/core/hle/result.h
diff options
context:
space:
mode:
Diffstat (limited to 'src/core/hle/result.h')
-rw-r--r--src/core/hle/result.h210
1 files changed, 68 insertions, 142 deletions
diff --git a/src/core/hle/result.h b/src/core/hle/result.h
index 2c6b24848..3807b9aa8 100644
--- a/src/core/hle/result.h
+++ b/src/core/hle/result.h
@@ -4,11 +4,10 @@
#pragma once
-#include <new>
-#include <utility>
#include "common/assert.h"
#include "common/bit_field.h"
#include "common/common_types.h"
+#include "common/expected.h"
// All the constants in this file come from http://switchbrew.org/index.php?title=Error_codes
@@ -155,203 +154,130 @@ constexpr ResultCode ResultSuccess(0);
constexpr ResultCode ResultUnknown(UINT32_MAX);
/**
- * This is an optional value type. It holds a `ResultCode` and, if that code is a success code,
- * also holds a result of type `T`. If the code is an error code then trying to access the inner
- * value fails, thus ensuring that the ResultCode of functions is always checked properly before
- * their return value is used. It is similar in concept to the `std::optional` type
- * (http://en.cppreference.com/w/cpp/experimental/optional) originally proposed for inclusion in
- * C++14, or the `Result` type in Rust (http://doc.rust-lang.org/std/result/index.html).
+ * This is an optional value type. It holds a `ResultCode` 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 ResultCode(ErrorDescription::OutOfRange, ErrorModule::Common,
- * ErrorSummary::InvalidArgument, ErrorLevel::Permanent);
+ * return ResultCode{ErrorModule::Common, 1};
* } else {
* // Frobnicated! Give caller a cookie
- * return MakeResult<int>(42);
+ * return 42;
* }
* }
* \endcode
*
* \code
- * ResultVal<int> frob_result = Frobnicate(0.75f);
+ * 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().hex);
+ * printf("Guess I overdid it. :( Error code: %ux\n", frob_result.Code().raw);
* }
* \endcode
*/
template <typename T>
class ResultVal {
public:
- /// Constructs an empty `ResultVal` with the given error code. The code must not be a success
- /// code.
- ResultVal(ResultCode error_code = ResultUnknown) : result_code(error_code) {
- ASSERT(error_code.IsError());
- }
+ constexpr ResultVal() : expected{} {}
+
+ constexpr ResultVal(ResultCode code) : expected{Common::Unexpected(code)} {}
+
+ template <typename U>
+ constexpr ResultVal(U&& val) : expected{std::forward<U>(val)} {}
- /**
- * Similar to the non-member function `MakeResult`, with the exception that you can manually
- * specify the success code. `success_code` must not be an error code.
- */
template <typename... Args>
- [[nodiscard]] static ResultVal WithCode(ResultCode success_code, Args&&... args) {
- ResultVal<T> result;
- result.emplace(success_code, std::forward<Args>(args)...);
- return result;
- }
+ constexpr ResultVal(Args&&... args) : expected{std::in_place, std::forward<Args>(args)...} {}
- ResultVal(const ResultVal& o) noexcept : result_code(o.result_code) {
- if (!o.empty()) {
- new (&object) T(o.object);
- }
- }
+ ~ResultVal() = default;
- ResultVal(ResultVal&& o) noexcept : result_code(o.result_code) {
- if (!o.empty()) {
- new (&object) T(std::move(o.object));
- }
- }
+ constexpr ResultVal(const ResultVal&) = default;
+ constexpr ResultVal(ResultVal&&) = default;
- ~ResultVal() {
- if (!empty()) {
- object.~T();
- }
- }
+ ResultVal& operator=(const ResultVal&) = default;
+ ResultVal& operator=(ResultVal&&) = default;
- ResultVal& operator=(const ResultVal& o) noexcept {
- if (this == &o) {
- return *this;
- }
- if (!empty()) {
- if (!o.empty()) {
- object = o.object;
- } else {
- object.~T();
- }
- } else {
- if (!o.empty()) {
- new (&object) T(o.object);
- }
- }
- result_code = o.result_code;
-
- return *this;
+ [[nodiscard]] constexpr explicit operator bool() const noexcept {
+ return expected.has_value();
}
- ResultVal& operator=(ResultVal&& o) noexcept {
- if (this == &o) {
- return *this;
- }
- if (!empty()) {
- if (!o.empty()) {
- object = std::move(o.object);
- } else {
- object.~T();
- }
- } else {
- if (!o.empty()) {
- new (&object) T(std::move(o.object));
- }
- }
- result_code = o.result_code;
-
- return *this;
+ [[nodiscard]] constexpr ResultCode Code() const {
+ return expected.has_value() ? ResultSuccess : expected.error();
}
- /**
- * Replaces the current result with a new constructed result value in-place. The code must not
- * be an error code.
- */
- template <typename... Args>
- void emplace(ResultCode success_code, Args&&... args) {
- ASSERT(success_code.IsSuccess());
- if (!empty()) {
- object.~T();
- }
- new (&object) T(std::forward<Args>(args)...);
- result_code = success_code;
+ [[nodiscard]] constexpr bool Succeeded() const {
+ return expected.has_value();
}
- /// Returns true if the `ResultVal` contains an error code and no value.
- [[nodiscard]] bool empty() const {
- return result_code.IsError();
+ [[nodiscard]] constexpr bool Failed() const {
+ return !expected.has_value();
}
- /// Returns true if the `ResultVal` contains a return value.
- [[nodiscard]] bool Succeeded() const {
- return result_code.IsSuccess();
+ [[nodiscard]] constexpr T* operator->() {
+ return std::addressof(expected.value());
}
- /// Returns true if the `ResultVal` contains an error code and no value.
- [[nodiscard]] bool Failed() const {
- return empty();
+
+ [[nodiscard]] constexpr const T* operator->() const {
+ return std::addressof(expected.value());
}
- [[nodiscard]] ResultCode Code() const {
- return result_code;
+ [[nodiscard]] constexpr T& operator*() & {
+ return *expected;
}
- [[nodiscard]] const T& operator*() const {
- return object;
+ [[nodiscard]] constexpr const T& operator*() const& {
+ return *expected;
}
- [[nodiscard]] T& operator*() {
- return object;
+
+ [[nodiscard]] constexpr T&& operator*() && {
+ return *expected;
}
- [[nodiscard]] const T* operator->() const {
- return &object;
+
+ [[nodiscard]] constexpr const T&& operator*() const&& {
+ return *expected;
}
- [[nodiscard]] T* operator->() {
- return &object;
+
+ [[nodiscard]] constexpr T& Unwrap() & {
+ ASSERT_MSG(Succeeded(), "Tried to Unwrap empty ResultVal");
+ return expected.value();
}
- /// Returns the value contained in this `ResultVal`, or the supplied default if it is missing.
- template <typename U>
- [[nodiscard]] T ValueOr(U&& value) const {
- return !empty() ? object : std::move(value);
+ [[nodiscard]] constexpr const T& Unwrap() const& {
+ ASSERT_MSG(Succeeded(), "Tried to Unwrap empty ResultVal");
+ return expected.value();
}
- /// Asserts that the result succeeded and returns a reference to it.
- [[nodiscard]] T& Unwrap() & {
+ [[nodiscard]] constexpr T&& Unwrap() && {
ASSERT_MSG(Succeeded(), "Tried to Unwrap empty ResultVal");
- return **this;
+ return std::move(expected.value());
}
- [[nodiscard]] T&& Unwrap() && {
+ [[nodiscard]] constexpr const T&& Unwrap() const&& {
ASSERT_MSG(Succeeded(), "Tried to Unwrap empty ResultVal");
- return std::move(**this);
+ return std::move(expected.value());
}
-private:
- // A union is used to allocate the storage for the value, while allowing us to construct and
- // destruct it at will.
- union {
- T object;
- };
- ResultCode result_code;
-};
+ template <typename U>
+ [[nodiscard]] constexpr T ValueOr(U&& v) const& {
+ return expected.value_or(v);
+ }
-/**
- * This function is a helper used to construct `ResultVal`s. It receives the arguments to construct
- * `T` with and creates a success `ResultVal` contained the constructed value.
- */
-template <typename T, typename... Args>
-[[nodiscard]] ResultVal<T> MakeResult(Args&&... args) {
- return ResultVal<T>::WithCode(ResultSuccess, std::forward<Args>(args)...);
-}
+ template <typename U>
+ [[nodiscard]] constexpr T ValueOr(U&& v) && {
+ return expected.value_or(v);
+ }
-/**
- * Deducible overload of MakeResult, allowing the template parameter to be ommited if you're just
- * copy or move constructing.
- */
-template <typename Arg>
-[[nodiscard]] ResultVal<std::remove_cvref_t<Arg>> MakeResult(Arg&& arg) {
- return ResultVal<std::remove_cvref_t<Arg>>::WithCode(ResultSuccess, std::forward<Arg>(arg));
-}
+private:
+ // TODO: Replace this with std::expected once it is standardized in the STL.
+ Common::Expected<T, ResultCode> expected;
+};
/**
* Check for the success of `source` (which must evaluate to a ResultVal). If it succeeds, unwraps