Allow `AREngine` to be used independently of `ARCodeFile` (#2108)

* Make `EmuInstance::cheatFile` use a `unique_ptr`

- Fixes a memory leak, as the cheat file wasn't cleaned up in the destructor

* Split `AREngine` and `ARCodeFile` apart

- Suitable for frontends that have their own way of storing cheats
- Store the cheats in `AREngine` in a `std::vector`
- Apparently cheats are _supposed_ to be executed each frame; I didn't understand this until recently

src/ARCodeFile.cpp

@@ -33,17 +33,26 @@ ARCodeFile::ARCodeFile(const std::string& filename)
 {
     Filename = filename;
 
-    Error = false;
-
-    Categories.clear();
-
     if (!Load())
         Error = true;
 }
 
-ARCodeFile::~ARCodeFile()
+std::vector<ARCode> ARCodeFile::GetCodes() const noexcept
 {
-    Categories.clear();
+    if (Error)
+        return {};
+
+    std::vector<ARCode> codes;
+
+    for (const ARCodeCat& cat : Categories)
+    {
+        for (const ARCode& code : cat.Codes)
+        {
+            codes.push_back(code);
+        }
+    }
+
+    return codes;
 }
 
 bool ARCodeFile::Load()

src/ARCodeFile.h

@@ -48,14 +48,16 @@ class ARCodeFile
 {
 public:
     ARCodeFile(const std::string& filename);
-    ~ARCodeFile();
+    ~ARCodeFile() noexcept = default;
 
-    bool Error;
+    [[nodiscard]] std::vector<ARCode> GetCodes() const noexcept;
+
+    bool Error = false;
 
     bool Load();
     bool Save();
 
-    ARCodeCatList Categories;
+    ARCodeCatList Categories {};
 
 private:
     std::string Filename;

src/AREngine.cpp

@@ -31,7 +31,6 @@ using Platform::LogLevel;
 
 AREngine::AREngine(melonDS::NDS& nds) : NDS(nds)
 {
-    CodeFile = nullptr;
 }
 
 #define case16(x) \
@@ -388,19 +387,12 @@ void AREngine::RunCheat(const ARCode& arcode)
 
 void AREngine::RunCheats()
 {
-    if (!CodeFile) return;
+    if (Cheats.empty()) return;
 
-    for (ARCodeCatList::iterator i = CodeFile->Categories.begin(); i != CodeFile->Categories.end(); i++)
+    for (const ARCode& code : Cheats)
     {
-        ARCodeCat& cat = *i;
-
-        for (ARCodeList::iterator j = cat.Codes.begin(); j != cat.Codes.end(); j++)
-        {
-            ARCode& code = *j;
-
         if (code.Enabled)
             RunCheat(code);
     }
-    }
 }
 }

src/AREngine.h

@@ -19,6 +19,7 @@
 #ifndef ARENGINE_H
 #define ARENGINE_H
 
+#include <vector>
 #include "ARCodeFile.h"
 
 namespace melonDS
@@ -29,14 +30,13 @@ class AREngine
 public:
     AREngine(melonDS::NDS& nds);
 
-    ARCodeFile* GetCodeFile() { return CodeFile; }
-    void SetCodeFile(ARCodeFile* file) { CodeFile = file; }
-
+    std::vector<ARCode> Cheats {};
+private:
+    friend class ARM;
     void RunCheats();
     void RunCheat(const ARCode& arcode);
-private:
+
     melonDS::NDS& NDS;
-    ARCodeFile* CodeFile; // AR code file - frontend is responsible for managing this
 };
 
 }

src/frontend/qt_sdl/EmuInstance.cpp

@@ -686,12 +686,8 @@ void EmuInstance::undoStateLoad()
 
 void EmuInstance::unloadCheats()
 {
-    if (cheatFile)
-    {
-        delete cheatFile;
-        cheatFile = nullptr;
-        nds->AREngine.SetCodeFile(nullptr);
-    }
+    cheatFile = nullptr; // cleaned up by unique_ptr
+    nds->AREngine.Cheats.clear();
 }
 
 void EmuInstance::loadCheats()
@@ -701,9 +697,16 @@ void EmuInstance::loadCheats()
     std::string filename = getAssetPath(false, globalCfg.GetString("CheatFilePath"), ".mch");
 
     // TODO: check for error (malformed cheat file, ...)
-    cheatFile = new ARCodeFile(filename);
+    cheatFile = std::make_unique<ARCodeFile>(filename);
 
-    nds->AREngine.SetCodeFile(cheatsOn ? cheatFile : nullptr);
+    if (cheatsOn)
+    {
+        nds->AREngine.Cheats = cheatFile->GetCodes();
+    }
+    else
+    {
+        nds->AREngine.Cheats.clear();
+    }
 }
 
 std::unique_ptr<ARM9BIOSImage> EmuInstance::loadARM9BIOS() noexcept
@@ -1013,12 +1016,14 @@ void EmuInstance::enableCheats(bool enable)
 {
     cheatsOn = enable;
     if (cheatFile)
-        nds->AREngine.SetCodeFile(cheatsOn ? cheatFile : nullptr);
+        nds->AREngine.Cheats = cheatFile->GetCodes();
+    else
+        nds->AREngine.Cheats.clear();
 }
 
 ARCodeFile* EmuInstance::getCheatFile()
 {
-    return cheatFile;
+    return cheatFile.get();
 }
 
 void EmuInstance::setBatteryLevels()

src/frontend/qt_sdl/EmuInstance.h

@@ -256,7 +256,7 @@ private:
     bool savestateLoaded;
     std::string previousSaveFile;
 
-    melonDS::ARCodeFile* cheatFile;
+    std::unique_ptr<melonDS::ARCodeFile> cheatFile;
     bool cheatsOn;
 
     SDL_AudioDeviceID audioDevice;