refactor(error): added guards to result and misc refactorings to error

core/src/error/error.cpp

@@ -1,17 +0,0 @@
-#include "error.h"
-#include "logger.h"
-
-Error::Error(std::string message) : message(message) {
-}
-
-std::string Error::getMessage() {
-    return this->message;
-}
-
-void Error::logMessage(Logger::LogLevel logLevel) {
-    Logger::log(this->message, logLevel);
-}
-
-void Error::logMessageFatal() {
-    Logger::fatalError(this->message);
-}

core/src/error/error.h

@@ -5,13 +5,15 @@
 
 // Base class for all errors
 class Error {
-    std::string message;
+    std::string _errorType;
+    std::string _message;
 
 protected:
-    Error(std::string message);
+    inline Error(std::string errorType, std::string message) : _errorType(errorType), _message(message) {}
 
 public:
-    std::string getMessage();
-    void logMessage(Logger::LogLevel logLevel = Logger::LogLevel::ERROR);
-    void logMessageFatal();
+    inline std::string errorType() { return this->_errorType; }
+    inline std::string message() { return this->_message; }
+    inline void logMessage(Logger::LogLevel logLevel = Logger::LogLevel::ERROR) { Logger::log(this->_message, logLevel); }
+    void logMessageFatal() { Logger::fatalError(this->_message); }
 };

core/src/error/instance.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include "error.h"
+
+class NoSuchInstance : public Error {
+    public:
+    inline NoSuchInstance(std::string className) : Error("NoSuchInstance", "Cannot create instance of unknown type " + className) {}
+};
+
+class NoSuchService : public Error {
+    public:
+    inline NoSuchService(std::string className) : Error("NoSuchService", "Cannot insert service of unknown type " + className) {}
+};
+
+class ServiceAlreadyExists : public Error {
+    public:
+    inline ServiceAlreadyExists(std::string className) : Error("ServiceAlreadyExists", "Service " + className + " is already inserted") {}
+};

core/src/error/result.h

@@ -1,59 +1,68 @@
 #pragma once
 
-#include "error.h"
+#include "error/error.h"
 #include "logger.h"
 #include "panic.h"
 #include <optional>
 #include <string>
+#include <type_traits>
 #include <variant>
 
 struct DUMMY_VALUE {};
 
-template <typename Result, typename ...E>
+template <typename T_Result, typename ...T_Errors>
 class [[nodiscard]] result {
-    struct ErrorContainer {
-        std::variant<E...> error;
+    static_assert(std::conjunction_v<std::is_base_of<Error, T_Errors>...>, "result<T_Errors...> requires T_Errors to derive from Error");
+
+    struct error_state {
+        std::variant<T_Errors...> error;
     };
 
-    struct SuccessContainer {
-        Result success;
+    struct success_state {
+        T_Result success;
     };
 
-    std::variant<SuccessContainer, ErrorContainer> value;
+    std::variant<success_state, error_state> value;
 public:
-    result(Result success) : value(SuccessContainer { success }) {}
-    result(std::variant<E...> error) : value(ErrorContainer { error }) {}
+    result(T_Result success) : value(success_state { success }) {}
+    result(std::variant<T_Errors...> error) : value(error_state { error }) {}
+    template <typename T_Error, std::enable_if_t<std::disjunction_v<std::is_same<T_Error, T_Errors>...>, int> = 0>
+    result(T_Error error) : value(error_state { error }) {}
 
     // Expects the result to be successful, otherwise panic with error message
-    Result expect(std::string errMsg = "Unwrapped a result with failure value") {
-        if (is_success())
-            return std::get<SuccessContainer>(value).success;
-        Logger::fatalError(errMsg);
+    T_Result expect(std::string errMsg = "Expected result to contain success") {
+        if (isSuccess())
+            return std::get<success_state>(value).success;
+        std::visit([&](auto&& it) {
+            Logger::fatalErrorf("Unwrapped a result with error value: [%s] %s\n\t%s", it.errorType(), it.message(), errMsg);
+        }, error().value());
         panic();
     }
 
-    bool is_success() { return std::holds_alternative<SuccessContainer>(value); }
-    bool is_error() { return std::holds_alternative<ErrorContainer>(value); }
+    bool isSuccess() { return std::holds_alternative<success_state>(value); }
+    bool isError() { return std::holds_alternative<error_state>(value); }
 
-    std::optional<Result> success() { return is_success() ? std::get<SuccessContainer>(value).success : std::nullopt; }
-    std::optional<std::variant<E...>> error() { return is_error() ? std::make_optional(std::get<ErrorContainer>(value).error) : std::nullopt; }
+    std::optional<T_Result> success() { return isSuccess() ? std::get<success_state>(value).success : std::nullopt; }
+    std::optional<std::variant<T_Errors...>> error() { return isError() ? std::make_optional(std::get<error_state>(value).error) : std::nullopt; }
 
     void logError(Logger::LogLevel logLevel = Logger::LogLevel::ERROR) {
-        if (is_success()) return;
+        if (isSuccess()) return;
         std::visit([&](auto&& it) {
             it.logMessage(logLevel);
         }, error().value());
     }
 
     // Equivalent to .success
-    operator std::optional<Result>() { return success(); }
-    operator bool() { return is_success(); }
-    bool operator !() { return is_error(); }
+    operator std::optional<T_Result>() { return success(); }
+    operator bool() { return isSuccess(); }
+    bool operator !() { return isError(); }
 };
 
-template <typename ...E>
-class fallible : public result<DUMMY_VALUE, E...> {
+template <typename ...T_Errors>
+class [[nodiscard]] fallible : public result<DUMMY_VALUE, T_Errors...> {
 public:
-    fallible() : result<DUMMY_VALUE, E...>(DUMMY_VALUE {}) {}
-    fallible(std::variant<E...> error) : result<DUMMY_VALUE, E...>(error) {}
+    fallible() : result<DUMMY_VALUE, T_Errors...>(DUMMY_VALUE {}) {}
+    fallible(std::variant<T_Errors...> error) : result<DUMMY_VALUE, T_Errors...>(error) {}
+    template <typename T_Error, std::enable_if_t<std::disjunction_v<std::is_same<T_Error, T_Errors>...>, int> = 0>
+    fallible(T_Error error) : result<DUMMY_VALUE, T_Errors...>(error) {}
 };

core/src/objects/base/instance.cpp

@@ -240,7 +240,7 @@ void Instance::Serialize(pugi::xml_node parent) {
 result<InstanceRef, NoSuchInstance> Instance::Deserialize(pugi::xml_node node) {
     std::string className = node.attribute("class").value();
     if (INSTANCE_MAP.count(className) == 0) {
-        return std::variant<NoSuchInstance>(NoSuchInstance(className));
+        return NoSuchInstance(className);
     }
     // This will error if an abstract instance is used in the file. Oh well, not my prob rn.
     // printf("What are you? A %s sandwich\n", className.c_str());
@@ -265,7 +265,7 @@ result<InstanceRef, NoSuchInstance> Instance::Deserialize(pugi::xml_node node) {
     // Read children
     for (pugi::xml_node childNode : node.children("Item")) {
         result<InstanceRef, NoSuchInstance> child = Instance::Deserialize(childNode);
-        if (child.is_error()) {
+        if (child.isError()) {
             std::get<NoSuchInstance>(child.error().value()).logMessage();
             continue;
         }

core/src/objects/base/instance.h

@@ -13,7 +13,7 @@
 #include <expected.hpp>
 #include <pugixml.hpp>
 
-#include "error/error.h"
+#include "error/instance.h"
 #include "error/result.h"
 #include "member.h"
 
@@ -38,11 +38,6 @@ struct InstanceType {
     InstanceFlags flags;
 };
 
-// Errors
-class NoSuchInstance : public Error {
-    public:
-    inline NoSuchInstance(std::string className) : Error("Cannot create instance of unknown type " + className) {}
-};
 
 class DescendantsIterator;
 

core/src/objects/datamodel.cpp

@@ -93,7 +93,7 @@ void DataModel::DeserializeService(pugi::xml_node node) {
     // Add children
     for (pugi::xml_node childNode : node.children("Item")) {
         result<InstanceRef, NoSuchInstance> child = Instance::Deserialize(childNode);
-        if (child.is_error()) {
+        if (child.isError()) {
             std::get<NoSuchInstance>(child.error().value()).logMessage();
             continue;
         }

core/src/objects/datamodel.h

@@ -1,6 +1,5 @@
 #pragma once
 
-#include "base.h"
 #include "error/result.h"
 #include "logger.h"
 #include "objects/base/instance.h"
@@ -14,16 +13,6 @@ class Workspace;
 class DataModel;
 class Service;
 
-class NoSuchService : public Error {
-    public:
-    inline NoSuchService(std::string className) : Error("Cannot insert service of unknown type " + className) {}
-};
-
-class ServiceAlreadyExists : public Error {
-    public:
-    inline ServiceAlreadyExists(std::string className) : Error("Service " + className + " is already inserted") {}
-};
-
 // The root instance to all objects in the hierarchy
 class DataModel : public Instance {
 private: