1 files changed, 63 insertions, 18 deletions

diff --git a/src/core/hle/result.h b/src/core/hle/result.h
index 3807b9aa8..47a1b829b 100644
--- a/src/core/hle/result.h
+++ b/src/core/hle/result.h
@@ -1,6 +1,5 @@
-// Copyright 2014 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2014 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
@@ -112,15 +111,16 @@ enum class ErrorModule : u32 {
 };
 
 /// Encapsulates a Horizon OS error code, allowing it to be separated into its constituent fields.
-union ResultCode {
+union Result {
     u32 raw;
 
     BitField<0, 9, ErrorModule> module;
     BitField<9, 13, u32> description;
 
-    constexpr explicit ResultCode(u32 raw_) : raw(raw_) {}
+    Result() = default;
+    constexpr explicit Result(u32 raw_) : raw(raw_) {}
 
-    constexpr ResultCode(ErrorModule module_, u32 description_)
+    constexpr Result(ErrorModule module_, u32 description_)
         : raw(module.FormatValue(module_) | description.FormatValue(description_)) {}
 
     [[nodiscard]] constexpr bool IsSuccess() const {
@@ -131,19 +131,20 @@ union ResultCode {
         return !IsSuccess();
     }
 };
+static_assert(std::is_trivial_v<Result>);
 
-[[nodiscard]] constexpr bool operator==(const ResultCode& a, const ResultCode& b) {
+[[nodiscard]] constexpr bool operator==(const Result& a, const Result& b) {
     return a.raw == b.raw;
 }
 
-[[nodiscard]] constexpr bool operator!=(const ResultCode& a, const ResultCode& b) {
+[[nodiscard]] constexpr bool operator!=(const Result& a, const Result& b) {
     return !operator==(a, b);
 }
 
 // Convenience functions for creating some common kinds of errors:
 
-/// The default success `ResultCode`.
-constexpr ResultCode ResultSuccess(0);
+/// The default success `Result`.
+constexpr Result ResultSuccess(0);
 
 /**
  * Placeholder result code used for unknown error codes.
@@ -151,10 +152,52 @@ constexpr ResultCode ResultSuccess(0);
  * @note This should only be used when a particular error code
  *       is not known yet.
  */
-constexpr ResultCode ResultUnknown(UINT32_MAX);
+constexpr Result ResultUnknown(UINT32_MAX);
 
 /**
- * This is an optional value type. It holds a `ResultCode` and, if that code is ResultSuccess, it
+ * A ResultRange defines an inclusive range of error descriptions within an error module.
+ * This can be used to check whether the description of a given Result falls within the range.
+ * The conversion function returns a Result with its description set to description_start.
+ *
+ * An example of how it could be used:
+ * \code
+ * constexpr ResultRange ResultCommonError{ErrorModule::Common, 0, 9999};
+ *
+ * Result Example(int value) {
+ *     const Result result = OtherExample(value);
+ *
+ *     // This will only evaluate to true if result.module is ErrorModule::Common and
+ *     // result.description is in between 0 and 9999 inclusive.
+ *     if (ResultCommonError.Includes(result)) {
+ *         // This returns Result{ErrorModule::Common, 0};
+ *         return ResultCommonError;
+ *     }
+ *
+ *     return ResultSuccess;
+ * }
+ * \endcode
+ */
+class ResultRange {
+public:
+    consteval ResultRange(ErrorModule module, u32 description_start, u32 description_end_)
+        : code{module, description_start}, description_end{description_end_} {}
+
+    [[nodiscard]] constexpr operator Result() const {
+        return code;
+    }
+
+    [[nodiscard]] constexpr bool Includes(Result other) const {
+        return code.module == other.module && code.description <= other.description &&
+               other.description <= description_end;
+    }
+
+private:
+    Result code;
+    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(),
@@ -165,7 +208,7 @@ constexpr ResultCode ResultUnknown(UINT32_MAX);
  * ResultVal<int> Frobnicate(float strength) {
  *     if (strength < 0.f || strength > 1.0f) {
  *         // Can't frobnicate too weakly or too strongly
- *         return ResultCode{ErrorModule::Common, 1};
+ *         return Result{ErrorModule::Common, 1};
  *     } else {
  *         // Frobnicated! Give caller a cookie
  *         return 42;
@@ -188,7 +231,9 @@ class ResultVal {
 public:
     constexpr ResultVal() : expected{} {}
 
-    constexpr ResultVal(ResultCode code) : expected{Common::Unexpected(code)} {}
+    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)} {}
@@ -208,7 +253,7 @@ public:
         return expected.has_value();
     }
 
-    [[nodiscard]] constexpr ResultCode Code() const {
+    [[nodiscard]] constexpr Result Code() const {
         return expected.has_value() ? ResultSuccess : expected.error();
     }
 
@@ -275,8 +320,8 @@ public:
     }
 
 private:
-    // TODO: Replace this with std::expected once it is standardized in the STL.
-    Common::Expected<T, ResultCode> expected;
+    // TODO (Morph): Replace this with C++23 std::expected.
+    Common::Expected<T, Result> expected;
 };
 
 /**
@@ -293,7 +338,7 @@ private:
     target = std::move(*CONCAT2(check_result_L, __LINE__))
 
 /**
- * Analogous to CASCADE_RESULT, but for a bare ResultCode. The code will be propagated if
+ * Analogous to CASCADE_RESULT, but for a bare Result. The code will be propagated if
  * non-success, or discarded otherwise.
  */
 #define CASCADE_CODE(source)                                                                       \