From 6ae8d084b418b6f7863d46e5998e39dc8baccd9d Mon Sep 17 00:00:00 2001
From: wheremyfoodat <44909372+wheremyfoodat@users.noreply.github.com>
Date: Sat, 7 Oct 2023 22:10:10 +0300
Subject: [PATCH] Use mutex for synchronizing the UI with the emulator thread

---
 include/panda_qt/main_window.hpp |  7 +++--
 src/panda_qt/main_window.cpp     | 48 ++++++++++++++++++++++++--------
 2 files changed, 41 insertions(+), 14 deletions(-)

diff --git a/include/panda_qt/main_window.hpp b/include/panda_qt/main_window.hpp
index e4a45487..3bbabf35 100644
--- a/include/panda_qt/main_window.hpp
+++ b/include/panda_qt/main_window.hpp
@@ -6,8 +6,9 @@
 #include <QPalette>
 #include <QtWidgets>
 #include <atomic>
-#include <thread>
 #include <filesystem>
+#include <thread>
+#include <mutex>
 
 #include "emulator.hpp"
 #include "panda_qt/screen.hpp"
@@ -27,9 +28,11 @@ class MainWindow : public QMainWindow {
 	std::thread emuThread;
 
 	std::atomic<bool> appRunning = true; // Is the application itself running?
-	std::atomic<bool> needToLoadROM = false;
+	std::mutex messageQueueMutex; // Used for synchronizing messages between the emulator and UI
 	std::filesystem::path romToLoad = "";
 
+	bool needToLoadROM = false;
+
 	ScreenWidget screen;
 	QComboBox* themeSelect = nullptr;
 	QMenuBar* menuBar = nullptr;
diff --git a/src/panda_qt/main_window.cpp b/src/panda_qt/main_window.cpp
index 8c57e335..809f56e0 100644
--- a/src/panda_qt/main_window.cpp
+++ b/src/panda_qt/main_window.cpp
@@ -70,13 +70,17 @@ MainWindow::MainWindow(QApplication* app, QWidget* parent) : QMainWindow(parent)
 
 void MainWindow::emuThreadMainLoop() {
 	while (appRunning) {
-		if (needToLoadROM.load()) {
-			bool success = emu->loadROM(romToLoad);
-			if (!success) {
-				printf("Failed to load ROM");
-			}
+		{
+			std::unique_lock lock(messageQueueMutex);
 
-			needToLoadROM.store(false, std::memory_order::seq_cst);
+			if (needToLoadROM) {
+				needToLoadROM = false;
+
+				bool success = emu->loadROM(romToLoad);
+				if (!success) {
+					printf("Failed to load ROM");
+				}
+			}
 		}
 
 		emu->runFrame();
@@ -99,17 +103,22 @@ void MainWindow::swapEmuBuffer() {
 
 void MainWindow::selectROM() {
 	// Are we already waiting for a ROM to be loaded? Then complain about it!
-	if (needToLoadROM.load()) {
-		QMessageBox::warning(this, tr("Already loading ROM"), tr("Panda3DS is already busy loading a ROM, please wait"));
-		return;
+	{
+		std::unique_lock lock(messageQueueMutex);
+		if (needToLoadROM) {
+			QMessageBox::warning(this, tr("Already loading ROM"), tr("Panda3DS is already busy loading a ROM, please wait"));
+			return;
+		}
 	}
 
 	auto path =
 		QFileDialog::getOpenFileName(this, tr("Select 3DS ROM to load"), "", tr("Nintendo 3DS ROMs (*.3ds *.cci *.cxi *.app *.3dsx *.elf *.axf)"));
 
 	if (!path.isEmpty()) {
+		std::unique_lock lock(messageQueueMutex);
+
 		romToLoad = path.toStdU16String();
-		needToLoadROM.store(true, std::memory_order_seq_cst);
+		needToLoadROM = true;
 	}
 }
 
@@ -184,7 +193,6 @@ void MainWindow::setTheme(Theme theme) {
 }
 
 void MainWindow::dumpRomFS() {
-	// TODO: LOCK FILE MUTEX HERE
 	auto folder = QFileDialog::getExistingDirectory(
 		this, tr("Select folder to dump RomFS files to"), "", QFileDialog::ShowDirsOnly | QFileDialog::DontResolveSymlinks
 	);
@@ -192,7 +200,23 @@ void MainWindow::dumpRomFS() {
 	if (folder.isEmpty()) {
 		return;
 	}
-
 	std::filesystem::path path(folder.toStdU16String());
+	
+	// TODO: This might break if the game accesses RomFS while we're dumping, we should move it to the emulator thread when we've got a message queue going
+	messageQueueMutex.lock();
 	RomFS::DumpingResult res = emu->dumpRomFS(path);
+	messageQueueMutex.unlock();
+
+	switch (res) {
+		case RomFS::DumpingResult::Success: break; // Yay!
+		case RomFS::DumpingResult::InvalidFormat:
+			QMessageBox::warning(
+				this, tr("Invalid format for RomFS dumping"), tr("The currently loaded app is not in a format that supports RomFS!")
+			);
+			break;
+
+		case RomFS::DumpingResult::NoRomFS:
+			QMessageBox::warning(this, tr("No RomFS found"), tr("No RomFS partition was found in the loaded app"));
+			break;
+	}
 }
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