early-access version 4088

README.md

@@ -1,7 +1,7 @@
 yuzu emulator early access
 =============
 
-This is the source code for early-access 4087.
+This is the source code for early-access 4088.
 
 ## Legal Notice
 

src/android/app/src/main/java/org/yuzu/yuzu_emu/NativeLibrary.kt

@@ -303,6 +303,11 @@ object NativeLibrary {
      */
     external fun getCpuBackend(): String
 
+    /**
+     * Returns the current GPU Driver.
+     */
+    external fun getGpuDriver(): String
+
     external fun applySettings()
 
     external fun logSettings()
@@ -614,6 +619,11 @@ object NativeLibrary {
      */
     external fun clearFilesystemProvider()
 
+    /**
+     * Checks if all necessary keys are present for decryption
+     */
+    external fun areKeysPresent(): Boolean
+
     /**
      * Button type for use in onTouchEvent
      */

src/android/app/src/main/java/org/yuzu/yuzu_emu/adapters/AbstractDiffAdapter.kt

@@ -14,16 +14,21 @@ import androidx.recyclerview.widget.RecyclerView
  * Generic adapter that implements an [AsyncDifferConfig] and covers some of the basic boilerplate
  * code used in every [RecyclerView].
  * Type assigned to [Model] must inherit from [Object] in order to be compared properly.
+ * @param exact Decides whether each item will be compared by reference or by their contents
  */
-abstract class AbstractDiffAdapter<Model : Any, Holder : AbstractViewHolder<Model>> :
+abstract class AbstractDiffAdapter<Model : Any, Holder : AbstractViewHolder<Model>>(
-    ListAdapter<Model, Holder>(AsyncDifferConfig.Builder(DiffCallback<Model>()).build()) {
+    exact: Boolean = true
+) : ListAdapter<Model, Holder>(AsyncDifferConfig.Builder(DiffCallback<Model>(exact)).build()) {
     override fun onBindViewHolder(holder: Holder, position: Int) =
         holder.bind(currentList[position])
 
-    private class DiffCallback<Model> : DiffUtil.ItemCallback<Model>() {
+    private class DiffCallback<Model>(val exact: Boolean) : DiffUtil.ItemCallback<Model>() {
         override fun areItemsTheSame(oldItem: Model & Any, newItem: Model & Any): Boolean {
+            if (exact) {
                 return oldItem === newItem
             }
+            return oldItem == newItem
+        }
 
         @SuppressLint("DiffUtilEquals")
         override fun areContentsTheSame(oldItem: Model & Any, newItem: Model & Any): Boolean {

src/android/app/src/main/java/org/yuzu/yuzu_emu/adapters/GameAdapter.kt

@@ -30,7 +30,7 @@ import org.yuzu.yuzu_emu.utils.GameIconUtils
 import org.yuzu.yuzu_emu.viewholder.AbstractViewHolder
 
 class GameAdapter(private val activity: AppCompatActivity) :
-    AbstractDiffAdapter<Game, GameAdapter.GameViewHolder>() {
+    AbstractDiffAdapter<Game, GameAdapter.GameViewHolder>(exact = false) {
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): GameViewHolder {
         CardGameBinding.inflate(LayoutInflater.from(parent.context), parent, false)
             .also { return GameViewHolder(it) }

src/android/app/src/main/java/org/yuzu/yuzu_emu/fragments/EmulationFragment.kt

@@ -38,7 +38,6 @@ import androidx.window.layout.WindowLayoutInfo
 import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import com.google.android.material.slider.Slider
 import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.launch
 import org.yuzu.yuzu_emu.HomeNavigationDirections
@@ -141,7 +140,9 @@ class EmulationFragment : Fragment(), SurfaceHolder.Callback {
 
         // So this fragment doesn't restart on configuration changes; i.e. rotation.
         retainInstance = true
-        emulationState = EmulationState(game.path)
+        emulationState = EmulationState(game.path) {
+            return@EmulationState driverViewModel.isInteractionAllowed.value
+        }
     }
 
     /**
@@ -370,6 +371,15 @@ class EmulationFragment : Fragment(), SurfaceHolder.Callback {
                     }
                 }
             }
+            launch {
+                repeatOnLifecycle(Lifecycle.State.RESUMED) {
+                    driverViewModel.isInteractionAllowed.collect {
+                        if (it) {
+                            startEmulation()
+                        }
+                    }
+                }
+            }
             launch {
                 repeatOnLifecycle(Lifecycle.State.CREATED) {
                     emulationViewModel.emulationStarted.collectLatest {
@@ -398,19 +408,10 @@ class EmulationFragment : Fragment(), SurfaceHolder.Callback {
                     }
                 }
             }
-            launch {
-                repeatOnLifecycle(Lifecycle.State.RESUMED) {
-                    driverViewModel.isInteractionAllowed.collect {
-                        if (it) {
-                            onEmulationStart()
-                        }
-                    }
-                }
-            }
         }
     }
 
-    private fun onEmulationStart() {
+    private fun startEmulation() {
         if (!NativeLibrary.isRunning() && !NativeLibrary.isPaused()) {
             if (!DirectoryInitialization.areDirectoriesReady) {
                 DirectoryInitialization.start()
@@ -485,12 +486,15 @@ class EmulationFragment : Fragment(), SurfaceHolder.Callback {
             val FRAMETIME = 2
             val SPEED = 3
             perfStatsUpdater = {
-                if (emulationViewModel.emulationStarted.value) {
+                if (emulationViewModel.emulationStarted.value &&
+                    !emulationViewModel.isEmulationStopping.value
+                ) {
                     val perfStats = NativeLibrary.getPerfStats()
                     val cpuBackend = NativeLibrary.getCpuBackend()
+                    val gpuDriver = NativeLibrary.getGpuDriver()
                     if (_binding != null) {
                         binding.showFpsText.text =
-                            String.format("FPS: %.1f\n%s", perfStats[FPS], cpuBackend)
+                            String.format("FPS: %.1f\n%s/%s", perfStats[FPS], cpuBackend, gpuDriver)
                     }
                     perfStatsUpdateHandler.postDelayed(perfStatsUpdater!!, 800)
                 }
@@ -807,7 +811,10 @@ class EmulationFragment : Fragment(), SurfaceHolder.Callback {
         }
     }
 
-    private class EmulationState(private val gamePath: String) {
+    private class EmulationState(
+        private val gamePath: String,
+        private val emulationCanStart: () -> Boolean
+    ) {
         private var state: State
         private var surface: Surface? = null
 
@@ -901,6 +908,7 @@ class EmulationFragment : Fragment(), SurfaceHolder.Callback {
                     State.PAUSED -> Log.warning(
                         "[EmulationFragment] Surface cleared while emulation paused."
                     )
+
                     else -> Log.warning(
                         "[EmulationFragment] Surface cleared while emulation stopped."
                     )
@@ -910,6 +918,10 @@ class EmulationFragment : Fragment(), SurfaceHolder.Callback {
 
         private fun runWithValidSurface() {
             NativeLibrary.surfaceChanged(surface)
+            if (!emulationCanStart.invoke()) {
+                return
+            }
+
             when (state) {
                 State.STOPPED -> {
                     val emulationThread = Thread({

src/android/app/src/main/java/org/yuzu/yuzu_emu/fragments/MessageDialogFragment.kt

@@ -26,9 +26,15 @@ class MessageDialogFragment : DialogFragment() {
         val descriptionId = requireArguments().getInt(DESCRIPTION_ID)
         val descriptionString = requireArguments().getString(DESCRIPTION_STRING)!!
         val helpLinkId = requireArguments().getInt(HELP_LINK)
+        val dismissible = requireArguments().getBoolean(DISMISSIBLE)
+        val clearPositiveAction = requireArguments().getBoolean(CLEAR_POSITIVE_ACTION)
 
         val builder = MaterialAlertDialogBuilder(requireContext())
 
+        if (clearPositiveAction) {
+            messageDialogViewModel.positiveAction = null
+        }
+
         if (messageDialogViewModel.positiveAction == null) {
             builder.setPositiveButton(R.string.close, null)
         } else {
@@ -51,6 +57,8 @@ class MessageDialogFragment : DialogFragment() {
             }
         }
 
+        isCancelable = dismissible
+
         return builder.show()
     }
 
@@ -67,6 +75,8 @@ class MessageDialogFragment : DialogFragment() {
         private const val DESCRIPTION_ID = "DescriptionId"
         private const val DESCRIPTION_STRING = "DescriptionString"
         private const val HELP_LINK = "Link"
+        private const val DISMISSIBLE = "Dismissible"
+        private const val CLEAR_POSITIVE_ACTION = "ClearPositiveAction"
 
         fun newInstance(
             activity: FragmentActivity? = null,
@@ -75,22 +85,28 @@ class MessageDialogFragment : DialogFragment() {
             descriptionId: Int = 0,
             descriptionString: String = "",
             helpLinkId: Int = 0,
+            dismissible: Boolean = true,
             positiveAction: (() -> Unit)? = null
         ): MessageDialogFragment {
-            val dialog = MessageDialogFragment()
+            var clearPositiveAction = false
-            val bundle = Bundle()
-            bundle.apply {
-                putInt(TITLE_ID, titleId)
-                putString(TITLE_STRING, titleString)
-                putInt(DESCRIPTION_ID, descriptionId)
-                putString(DESCRIPTION_STRING, descriptionString)
-                putInt(HELP_LINK, helpLinkId)
-            }
             if (activity != null) {
                 ViewModelProvider(activity)[MessageDialogViewModel::class.java].apply {
                     clear()
                     this.positiveAction = positiveAction
                 }
+            } else {
+                clearPositiveAction = true
+            }
+
+            val dialog = MessageDialogFragment()
+            val bundle = Bundle().apply {
+                putInt(TITLE_ID, titleId)
+                putString(TITLE_STRING, titleString)
+                putInt(DESCRIPTION_ID, descriptionId)
+                putString(DESCRIPTION_STRING, descriptionString)
+                putInt(HELP_LINK, helpLinkId)
+                putBoolean(DISMISSIBLE, dismissible)
+                putBoolean(CLEAR_POSITIVE_ACTION, clearPositiveAction)
             }
             dialog.arguments = bundle
             return dialog

src/android/app/src/main/java/org/yuzu/yuzu_emu/fragments/SetupFragment.kt

@@ -31,6 +31,7 @@ import androidx.preference.PreferenceManager
 import androidx.viewpager2.widget.ViewPager2.OnPageChangeCallback
 import com.google.android.material.transition.MaterialFadeThrough
 import kotlinx.coroutines.launch
+import org.yuzu.yuzu_emu.NativeLibrary
 import java.io.File
 import org.yuzu.yuzu_emu.R
 import org.yuzu.yuzu_emu.YuzuApplication
@@ -162,7 +163,7 @@ class SetupFragment : Fragment() {
                     R.string.install_prod_keys_warning_help,
                     {
                         val file = File(DirectoryInitialization.userDirectory + "/keys/prod.keys")
-                        if (file.exists()) {
+                        if (file.exists() && NativeLibrary.areKeysPresent()) {
                             StepState.COMPLETE
                         } else {
                             StepState.INCOMPLETE
@@ -347,7 +348,8 @@ class SetupFragment : Fragment() {
     val getProdKey =
         registerForActivityResult(ActivityResultContracts.OpenDocument()) { result ->
             if (result != null) {
-                if (mainActivity.processKey(result)) {
+                mainActivity.processKey(result)
+                if (NativeLibrary.areKeysPresent()) {
                     keyCallback.onStepCompleted()
                 }
             }

src/android/app/src/main/java/org/yuzu/yuzu_emu/model/DriverViewModel.kt

@@ -144,6 +144,7 @@ class DriverViewModel : ViewModel() {
         val selectedDriverFile = File(StringSetting.DRIVER_PATH.getString())
         val selectedDriverMetadata = GpuDriverHelper.customDriverSettingData
         if (GpuDriverHelper.installedCustomDriverData == selectedDriverMetadata) {
+            setDriverReady()
             return
         }
 

src/android/app/src/main/java/org/yuzu/yuzu_emu/model/Game.kt

@@ -70,11 +70,19 @@ class Game(
         }
 
     override fun equals(other: Any?): Boolean {
-        if (other !is Game) {
+        if (this === other) return true
-            return false
+        if (javaClass != other?.javaClass) return false
-        }
 
-        return hashCode() == other.hashCode()
+        other as Game
+
+        if (title != other.title) return false
+        if (path != other.path) return false
+        if (programId != other.programId) return false
+        if (developer != other.developer) return false
+        if (version != other.version) return false
+        if (isHomebrew != other.isHomebrew) return false
+
+        return true
     }
 
     override fun hashCode(): Int {

src/android/app/src/main/java/org/yuzu/yuzu_emu/model/HomeViewModel.kt

@@ -31,6 +31,9 @@ class HomeViewModel : ViewModel() {
     private val _reloadPropertiesList = MutableStateFlow(false)
     val reloadPropertiesList get() = _reloadPropertiesList.asStateFlow()
 
+    private val _checkKeys = MutableStateFlow(false)
+    val checkKeys = _checkKeys.asStateFlow()
+
     var navigatedToSetup = false
 
     fun setNavigationVisibility(visible: Boolean, animated: Boolean) {
@@ -66,4 +69,8 @@ class HomeViewModel : ViewModel() {
     fun reloadPropertiesList(reload: Boolean) {
         _reloadPropertiesList.value = reload
     }
+
+    fun setCheckKeys(value: Boolean) {
+        _checkKeys.value = value
+    }
 }

src/android/app/src/main/java/org/yuzu/yuzu_emu/ui/main/MainActivity.kt

@@ -64,6 +64,9 @@ class MainActivity : AppCompatActivity(), ThemeProvider {
 
     override var themeId: Int = 0
 
+    private val CHECKED_DECRYPTION = "CheckedDecryption"
+    private var checkedDecryption = false
+
     override fun onCreate(savedInstanceState: Bundle?) {
         val splashScreen = installSplashScreen()
         splashScreen.setKeepOnScreenCondition { !DirectoryInitialization.areDirectoriesReady }
@@ -75,6 +78,18 @@ class MainActivity : AppCompatActivity(), ThemeProvider {
         binding = ActivityMainBinding.inflate(layoutInflater)
         setContentView(binding.root)
 
+        if (savedInstanceState != null) {
+            checkedDecryption = savedInstanceState.getBoolean(CHECKED_DECRYPTION)
+        }
+        if (!checkedDecryption) {
+            val firstTimeSetup = PreferenceManager.getDefaultSharedPreferences(applicationContext)
+                .getBoolean(Settings.PREF_FIRST_APP_LAUNCH, true)
+            if (!firstTimeSetup) {
+                checkKeys()
+            }
+            checkedDecryption = true
+        }
+
         WindowCompat.setDecorFitsSystemWindows(window, false)
         window.setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_NOTHING)
 
@@ -150,6 +165,16 @@ class MainActivity : AppCompatActivity(), ThemeProvider {
                     }
                 }
             }
+            launch {
+                repeatOnLifecycle(Lifecycle.State.CREATED) {
+                    homeViewModel.checkKeys.collect {
+                        if (it) {
+                            checkKeys()
+                            homeViewModel.setCheckKeys(false)
+                        }
+                    }
+                }
+            }
         }
 
         // Dismiss previous notifications (should not happen unless a crash occurred)
@@ -158,6 +183,21 @@ class MainActivity : AppCompatActivity(), ThemeProvider {
         setInsets()
     }
 
+    private fun checkKeys() {
+        if (!NativeLibrary.areKeysPresent()) {
+            MessageDialogFragment.newInstance(
+                titleId = R.string.keys_missing,
+                descriptionId = R.string.keys_missing_description,
+                helpLinkId = R.string.keys_missing_help
+            ).show(supportFragmentManager, MessageDialogFragment.TAG)
+        }
+    }
+
+    override fun onSaveInstanceState(outState: Bundle) {
+        super.onSaveInstanceState(outState)
+        outState.putBoolean(CHECKED_DECRYPTION, checkedDecryption)
+    }
+
     fun finishSetup(navController: NavController) {
         navController.navigate(R.id.action_firstTimeSetupFragment_to_gamesFragment)
         (binding.navigationView as NavigationBarView).setupWithNavController(navController)
@@ -349,6 +389,7 @@ class MainActivity : AppCompatActivity(), ThemeProvider {
                     R.string.install_keys_success,
                     Toast.LENGTH_SHORT
                 ).show()
+                homeViewModel.setCheckKeys(true)
                 gamesViewModel.reloadGames(true)
                 return true
             } else {
@@ -399,6 +440,7 @@ class MainActivity : AppCompatActivity(), ThemeProvider {
                         firmwarePath.deleteRecursively()
                         cacheFirmwareDir.copyRecursively(firmwarePath, true)
                         NativeLibrary.initializeSystem(true)
+                        homeViewModel.setCheckKeys(true)
                         getString(R.string.save_file_imported_success)
                     }
                 } catch (e: Exception) {

src/android/app/src/main/jni/game_metadata.cpp

@@ -1,12 +1,12 @@
 // SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
-#include <core/core.h>
+#include "core/core.h"
-#include <core/file_sys/mode.h>
+#include "core/file_sys/fs_filesystem.h"
-#include <core/file_sys/patch_manager.h>
+#include "core/file_sys/patch_manager.h"
-#include <core/loader/nro.h>
-#include <jni.h>
 #include "core/loader/loader.h"
+#include "core/loader/nro.h"
+#include "jni.h"
 #include "jni/android_common/android_common.h"
 #include "native.h"
 
@@ -79,7 +79,7 @@ extern "C" {
 jboolean Java_org_yuzu_yuzu_1emu_utils_GameMetadata_getIsValid(JNIEnv* env, jobject obj,
                                                                jstring jpath) {
     const auto file = EmulationSession::GetInstance().System().GetFilesystem()->OpenFile(
-        GetJString(env, jpath), FileSys::Mode::Read);
+        GetJString(env, jpath), FileSys::OpenMode::Read);
     if (!file) {
         return false;
     }

src/android/app/src/main/jni/native.cpp

@@ -35,9 +35,10 @@
 #include "core/crypto/key_manager.h"
 #include "core/file_sys/card_image.h"
 #include "core/file_sys/content_archive.h"
+#include "core/file_sys/fs_filesystem.h"
 #include "core/file_sys/submission_package.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
-#include "core/file_sys/vfs_real.h"
+#include "core/file_sys/vfs/vfs_real.h"
 #include "core/frontend/applets/cabinet.h"
 #include "core/frontend/applets/controller.h"
 #include "core/frontend/applets/error.h"
@@ -154,7 +155,7 @@ void EmulationSession::SurfaceChanged() {
 }
 
 void EmulationSession::ConfigureFilesystemProvider(const std::string& filepath) {
-    const auto file = m_system.GetFilesystem()->OpenFile(filepath, FileSys::Mode::Read);
+    const auto file = m_system.GetFilesystem()->OpenFile(filepath, FileSys::OpenMode::Read);
     if (!file) {
         return;
     }
@@ -247,6 +248,7 @@ Core::SystemResultStatus EmulationSession::InitializeEmulation(const std::string
     m_system.GetCpuManager().OnGpuReady();
     m_system.RegisterExitCallback([&] { HaltEmulation(); });
 
+    OnEmulationStarted();
     return Core::SystemResultStatus::Success;
 }
 
@@ -463,8 +465,8 @@ int Java_org_yuzu_yuzu_1emu_NativeLibrary_installFileToNand(JNIEnv* env, jobject
     };
 
     return static_cast<int>(
-        ContentManager::InstallNSP(&EmulationSession::GetInstance().System(),
+        ContentManager::InstallNSP(EmulationSession::GetInstance().System(),
-                                   EmulationSession::GetInstance().System().GetFilesystem().get(),
+                                   *EmulationSession::GetInstance().System().GetFilesystem(),
                                    GetJString(env, j_file), callback));
 }
 
@@ -474,8 +476,8 @@ jboolean Java_org_yuzu_yuzu_1emu_NativeLibrary_doesUpdateMatchProgram(JNIEnv* en
     u64 program_id = EmulationSession::GetProgramId(env, jprogramId);
     std::string updatePath = GetJString(env, jupdatePath);
     std::shared_ptr<FileSys::NSP> nsp = std::make_shared<FileSys::NSP>(
-        EmulationSession::GetInstance().System().GetFilesystem()->OpenFile(updatePath,
+        EmulationSession::GetInstance().System().GetFilesystem()->OpenFile(
-                                                                           FileSys::Mode::Read));
+            updatePath, FileSys::OpenMode::Read));
     for (const auto& item : nsp->GetNCAs()) {
         for (const auto& nca_details : item.second) {
             if (nca_details.second->GetName().ends_with(".cnmt.nca")) {
@@ -674,6 +676,11 @@ jstring Java_org_yuzu_yuzu_1emu_NativeLibrary_getCpuBackend(JNIEnv* env, jclass
     return ToJString(env, "JIT");
 }
 
+jstring Java_org_yuzu_yuzu_1emu_NativeLibrary_getGpuDriver(JNIEnv* env, jobject jobj) {
+    return ToJString(env,
+                     EmulationSession::GetInstance().System().GPU().Renderer().GetDeviceVendor());
+}
+
 void Java_org_yuzu_yuzu_1emu_NativeLibrary_applySettings(JNIEnv* env, jobject jobj) {
     EmulationSession::GetInstance().System().ApplySettings();
 }
@@ -713,7 +720,7 @@ void Java_org_yuzu_yuzu_1emu_NativeLibrary_initializeEmptyUserDirectory(JNIEnv*
                                                                         jobject instance) {
     const auto nand_dir = Common::FS::GetYuzuPath(Common::FS::YuzuPath::NANDDir);
     auto vfs_nand_dir = EmulationSession::GetInstance().System().GetFilesystem()->OpenDirectory(
-        Common::FS::PathToUTF8String(nand_dir), FileSys::Mode::Read);
+        Common::FS::PathToUTF8String(nand_dir), FileSys::OpenMode::Read);
 
     const auto user_id = EmulationSession::GetInstance().System().GetProfileManager().GetUser(
         static_cast<std::size_t>(0));
@@ -819,7 +826,7 @@ void Java_org_yuzu_yuzu_1emu_NativeLibrary_removeUpdate(JNIEnv* env, jobject job
 void Java_org_yuzu_yuzu_1emu_NativeLibrary_removeDLC(JNIEnv* env, jobject jobj,
                                                      jstring jprogramId) {
     auto program_id = EmulationSession::GetProgramId(env, jprogramId);
-    ContentManager::RemoveAllDLC(&EmulationSession::GetInstance().System(), program_id);
+    ContentManager::RemoveAllDLC(EmulationSession::GetInstance().System(), program_id);
 }
 
 void Java_org_yuzu_yuzu_1emu_NativeLibrary_removeMod(JNIEnv* env, jobject jobj, jstring jprogramId,
@@ -829,7 +836,8 @@ void Java_org_yuzu_yuzu_1emu_NativeLibrary_removeMod(JNIEnv* env, jobject jobj,
                               program_id, GetJString(env, jname));
 }
 
-jobject Java_org_yuzu_yuzu_1emu_NativeLibrary_verifyInstalledContents(JNIEnv* env, jobject jobj,
+jobjectArray Java_org_yuzu_yuzu_1emu_NativeLibrary_verifyInstalledContents(JNIEnv* env,
+                                                                           jobject jobj,
                                                                            jobject jcallback) {
     auto jlambdaClass = env->GetObjectClass(jcallback);
     auto jlambdaInvokeMethod = env->GetMethodID(
@@ -842,7 +850,7 @@ jobject Java_org_yuzu_yuzu_1emu_NativeLibrary_verifyInstalledContents(JNIEnv* en
 
     auto& session = EmulationSession::GetInstance();
     std::vector<std::string> result = ContentManager::VerifyInstalledContents(
-        &session.System(), session.GetContentProvider(), callback);
+        session.System(), *session.GetContentProvider(), callback);
     jobjectArray jresult =
         env->NewObjectArray(result.size(), IDCache::GetStringClass(), ToJString(env, ""));
     for (size_t i = 0; i < result.size(); ++i) {
@@ -863,7 +871,7 @@ jint Java_org_yuzu_yuzu_1emu_NativeLibrary_verifyGameContents(JNIEnv* env, jobje
     };
     auto& session = EmulationSession::GetInstance();
     return static_cast<jint>(
-        ContentManager::VerifyGameContents(&session.System(), GetJString(env, jpath), callback));
+        ContentManager::VerifyGameContents(session.System(), GetJString(env, jpath), callback));
 }
 
 jstring Java_org_yuzu_yuzu_1emu_NativeLibrary_getSavePath(JNIEnv* env, jobject jobj,
@@ -882,7 +890,7 @@ jstring Java_org_yuzu_yuzu_1emu_NativeLibrary_getSavePath(JNIEnv* env, jobject j
 
     const auto nandDir = Common::FS::GetYuzuPath(Common::FS::YuzuPath::NANDDir);
     auto vfsNandDir = system.GetFilesystem()->OpenDirectory(Common::FS::PathToUTF8String(nandDir),
-                                                            FileSys::Mode::Read);
+                                                            FileSys::OpenMode::Read);
 
     const auto user_save_data_path = FileSys::SaveDataFactory::GetFullPath(
         {}, vfsNandDir, FileSys::SaveDataSpaceId::NandUser, FileSys::SaveDataType::SaveData,
@@ -912,4 +920,10 @@ void Java_org_yuzu_yuzu_1emu_NativeLibrary_clearFilesystemProvider(JNIEnv* env,
     EmulationSession::GetInstance().GetContentProvider()->ClearAllEntries();
 }
 
+jboolean Java_org_yuzu_yuzu_1emu_NativeLibrary_areKeysPresent(JNIEnv* env, jobject jobj) {
+    auto& system = EmulationSession::GetInstance().System();
+    system.GetFileSystemController().CreateFactories(*system.GetFilesystem());
+    return ContentManager::AreKeysPresent();
+}
+
 } // extern "C"

src/android/app/src/main/res/values/strings.xml

@@ -144,6 +144,9 @@
     <string name="no_save_data_found">No save data found</string>
     <string name="verify_installed_content">Verify installed content</string>
     <string name="verify_installed_content_description">Checks all installed content for corruption</string>
+    <string name="keys_missing">Encryption keys are missing</string>
+    <string name="keys_missing_description">Firmware and retail games cannot be decrypted</string>
+    <string name="keys_missing_help">https://yuzu-emu.org/help/quickstart/#dumping-decryption-keys</string>
 
     <!-- Applet launcher strings -->
     <string name="applets">Applet launcher</string>

src/common/overflow.h

@@ -3,6 +3,7 @@
 
 #pragma once
 
+#include <algorithm>
 #include <type_traits>
 #include "bit_cast.h"
 
@@ -19,4 +20,21 @@ inline T WrappingAdd(T lhs, T rhs) {
     return BitCast<T>(lhs_u + rhs_u);
 }
 
+template <typename T>
+    requires(std::is_integral_v<T> && std::is_signed_v<T>)
+inline bool CanAddWithoutOverflow(T lhs, T rhs) {
+#ifdef _MSC_VER
+    if (lhs >= 0 && rhs >= 0) {
+        return WrappingAdd(lhs, rhs) >= std::max(lhs, rhs);
+    } else if (lhs < 0 && rhs < 0) {
+        return WrappingAdd(lhs, rhs) <= std::min(lhs, rhs);
+    } else {
+        return true;
+    }
+#else
+    T res;
+    return !__builtin_add_overflow(lhs, rhs, &res);
+#endif
+}
+
 } // namespace Common

src/core/CMakeLists.txt

@@ -20,28 +20,49 @@ add_library(core STATIC
     cpu_manager.h
     crypto/aes_util.cpp
     crypto/aes_util.h
+    crypto/ctr_encryption_layer.cpp
+    crypto/ctr_encryption_layer.h
     crypto/encryption_layer.cpp
     crypto/encryption_layer.h
     crypto/key_manager.cpp
     crypto/key_manager.h
     crypto/partition_data_manager.cpp
     crypto/partition_data_manager.h
-    crypto/ctr_encryption_layer.cpp
-    crypto/ctr_encryption_layer.h
     crypto/xts_encryption_layer.cpp
     crypto/xts_encryption_layer.h
-    debugger/debugger_interface.h
     debugger/debugger.cpp
     debugger/debugger.h
-    debugger/gdbstub_arch.cpp
+    debugger/debugger_interface.h
-    debugger/gdbstub_arch.h
     debugger/gdbstub.cpp
     debugger/gdbstub.h
+    debugger/gdbstub_arch.cpp
+    debugger/gdbstub_arch.h
     device_memory_manager.h
     device_memory_manager.inc
     device_memory.cpp
     device_memory.h
+    file_sys/bis_factory.cpp
+    file_sys/bis_factory.h
+    file_sys/card_image.cpp
+    file_sys/card_image.h
+    file_sys/common_funcs.h
+    file_sys/content_archive.cpp
+    file_sys/content_archive.h
+    file_sys/control_metadata.cpp
+    file_sys/control_metadata.h
+    file_sys/errors.h
+    file_sys/fs_directory.h
+    file_sys/fs_file.h
+    file_sys/fs_filesystem.h
+    file_sys/fs_memory_management.h
+    file_sys/fs_operate_range.h
+    file_sys/fs_path.h
+    file_sys/fs_path_utility.h
+    file_sys/fs_string_util.h
+    file_sys/fsmitm_romfsbuild.cpp
+    file_sys/fsmitm_romfsbuild.h
     file_sys/fssystem/fs_i_storage.h
+    file_sys/fssystem/fs_types.h
     file_sys/fssystem/fssystem_aes_ctr_counter_extended_storage.cpp
     file_sys/fssystem/fssystem_aes_ctr_counter_extended_storage.h
     file_sys/fssystem/fssystem_aes_ctr_storage.cpp
@@ -83,25 +104,10 @@ add_library(core STATIC
     file_sys/fssystem/fssystem_switch_storage.h
     file_sys/fssystem/fssystem_utility.cpp
     file_sys/fssystem/fssystem_utility.h
-    file_sys/fssystem/fs_types.h
-    file_sys/bis_factory.cpp
-    file_sys/bis_factory.h
-    file_sys/card_image.cpp
-    file_sys/card_image.h
-    file_sys/common_funcs.h
-    file_sys/content_archive.cpp
-    file_sys/content_archive.h
-    file_sys/control_metadata.cpp
-    file_sys/control_metadata.h
-    file_sys/directory.h
-    file_sys/errors.h
-    file_sys/fsmitm_romfsbuild.cpp
-    file_sys/fsmitm_romfsbuild.h
     file_sys/ips_layer.cpp
     file_sys/ips_layer.h
     file_sys/kernel_executable.cpp
     file_sys/kernel_executable.h
-    file_sys/mode.h
     file_sys/nca_metadata.cpp
     file_sys/nca_metadata.h
     file_sys/partition_filesystem.cpp
@@ -146,22 +152,22 @@ add_library(core STATIC
     file_sys/system_archive/system_version.h
     file_sys/system_archive/time_zone_binary.cpp
     file_sys/system_archive/time_zone_binary.h
-    file_sys/vfs.cpp
+    file_sys/vfs/vfs.cpp
-    file_sys/vfs.h
+    file_sys/vfs/vfs.h
-    file_sys/vfs_cached.cpp
+    file_sys/vfs/vfs_cached.cpp
-    file_sys/vfs_cached.h
+    file_sys/vfs/vfs_cached.h
-    file_sys/vfs_concat.cpp
+    file_sys/vfs/vfs_concat.cpp
-    file_sys/vfs_concat.h
+    file_sys/vfs/vfs_concat.h
-    file_sys/vfs_layered.cpp
+    file_sys/vfs/vfs_layered.cpp
-    file_sys/vfs_layered.h
+    file_sys/vfs/vfs_layered.h
-    file_sys/vfs_offset.cpp
+    file_sys/vfs/vfs_offset.cpp
-    file_sys/vfs_offset.h
+    file_sys/vfs/vfs_offset.h
-    file_sys/vfs_real.cpp
+    file_sys/vfs/vfs_real.cpp
-    file_sys/vfs_real.h
+    file_sys/vfs/vfs_real.h
-    file_sys/vfs_static.h
+    file_sys/vfs/vfs_static.h
-    file_sys/vfs_types.h
+    file_sys/vfs/vfs_types.h
-    file_sys/vfs_vector.cpp
+    file_sys/vfs/vfs_vector.cpp
-    file_sys/vfs_vector.h
+    file_sys/vfs/vfs_vector.h
     file_sys/xts_archive.cpp
     file_sys/xts_archive.h
     frontend/applets/cabinet.cpp
@@ -194,7 +200,6 @@ add_library(core STATIC
     hle/kernel/board/nintendo/nx/secure_monitor.h
     hle/kernel/code_set.cpp
     hle/kernel/code_set.h
-    hle/kernel/svc_results.h
     hle/kernel/global_scheduler_context.cpp
     hle/kernel/global_scheduler_context.h
     hle/kernel/init/init_slab_setup.cpp
@@ -204,11 +209,11 @@ add_library(core STATIC
     hle/kernel/k_address_arbiter.h
     hle/kernel/k_address_space_info.cpp
     hle/kernel/k_address_space_info.h
+    hle/kernel/k_affinity_mask.h
     hle/kernel/k_auto_object.cpp
     hle/kernel/k_auto_object.h
     hle/kernel/k_auto_object_container.cpp
     hle/kernel/k_auto_object_container.h
-    hle/kernel/k_affinity_mask.h
     hle/kernel/k_capabilities.cpp
     hle/kernel/k_capabilities.h
     hle/kernel/k_class_token.cpp
@@ -232,9 +237,9 @@ add_library(core STATIC
     hle/kernel/k_event_info.h
     hle/kernel/k_handle_table.cpp
     hle/kernel/k_handle_table.h
-    hle/kernel/k_hardware_timer_base.h
     hle/kernel/k_hardware_timer.cpp
     hle/kernel/k_hardware_timer.h
+    hle/kernel/k_hardware_timer_base.h
     hle/kernel/k_interrupt_manager.cpp
     hle/kernel/k_interrupt_manager.h
     hle/kernel/k_light_client_session.cpp
@@ -261,10 +266,10 @@ add_library(core STATIC
     hle/kernel/k_page_bitmap.h
     hle/kernel/k_page_buffer.cpp
     hle/kernel/k_page_buffer.h
-    hle/kernel/k_page_heap.cpp
-    hle/kernel/k_page_heap.h
     hle/kernel/k_page_group.cpp
     hle/kernel/k_page_group.h
+    hle/kernel/k_page_heap.cpp
+    hle/kernel/k_page_heap.h
     hle/kernel/k_page_table.h
     hle/kernel/k_page_table_base.cpp
     hle/kernel/k_page_table_base.h
@@ -329,8 +334,6 @@ add_library(core STATIC
     hle/kernel/slab_helpers.h
     hle/kernel/svc.cpp
     hle/kernel/svc.h
-    hle/kernel/svc_common.h
-    hle/kernel/svc_types.h
     hle/kernel/svc/svc_activity.cpp
     hle/kernel/svc/svc_address_arbiter.cpp
     hle/kernel/svc/svc_address_translation.cpp
@@ -368,6 +371,9 @@ add_library(core STATIC
     hle/kernel/svc/svc_thread_profiler.cpp
     hle/kernel/svc/svc_tick.cpp
     hle/kernel/svc/svc_transfer_memory.cpp
+    hle/kernel/svc_common.h
+    hle/kernel/svc_results.h
+    hle/kernel/svc_types.h
     hle/result.h
     hle/service/acc/acc.cpp
     hle/service/acc/acc.h
@@ -472,6 +478,8 @@ add_library(core STATIC
     hle/service/caps/caps_types.h
     hle/service/caps/caps_u.cpp
     hle/service/caps/caps_u.h
+    hle/service/cmif_serialization.h
+    hle/service/cmif_types.h
     hle/service/erpt/erpt.cpp
     hle/service/erpt/erpt.h
     hle/service/es/es.cpp
@@ -484,14 +492,25 @@ add_library(core STATIC
     hle/service/fatal/fatal_p.h
     hle/service/fatal/fatal_u.cpp
     hle/service/fatal/fatal_u.h
+    hle/service/fgm/fgm.cpp
+    hle/service/fgm/fgm.h
     hle/service/filesystem/filesystem.cpp
     hle/service/filesystem/filesystem.h
-    hle/service/filesystem/fsp_ldr.cpp
+    hle/service/filesystem/fsp/fs_i_directory.cpp
-    hle/service/filesystem/fsp_ldr.h
+    hle/service/filesystem/fsp/fs_i_directory.h
-    hle/service/filesystem/fsp_pr.cpp
+    hle/service/filesystem/fsp/fs_i_file.cpp
-    hle/service/filesystem/fsp_pr.h
+    hle/service/filesystem/fsp/fs_i_file.h
-    hle/service/filesystem/fsp_srv.cpp
+    hle/service/filesystem/fsp/fs_i_filesystem.cpp
-    hle/service/filesystem/fsp_srv.h
+    hle/service/filesystem/fsp/fs_i_filesystem.h
+    hle/service/filesystem/fsp/fs_i_storage.cpp
+    hle/service/filesystem/fsp/fs_i_storage.h
+    hle/service/filesystem/fsp/fsp_ldr.cpp
+    hle/service/filesystem/fsp/fsp_ldr.h
+    hle/service/filesystem/fsp/fsp_pr.cpp
+    hle/service/filesystem/fsp/fsp_pr.h
+    hle/service/filesystem/fsp/fsp_srv.cpp
+    hle/service/filesystem/fsp/fsp_srv.h
+    hle/service/filesystem/fsp/fsp_util.h
     hle/service/filesystem/romfs_controller.cpp
     hle/service/filesystem/romfs_controller.h
     hle/service/filesystem/save_data_controller.cpp
@@ -549,13 +568,18 @@ add_library(core STATIC
     hle/service/hid/irs.h
     hle/service/hid/xcd.cpp
     hle/service/hid/xcd.h
+    hle/service/hle_ipc.cpp
+    hle/service/hle_ipc.h
+    hle/service/ipc_helpers.h
+    hle/service/kernel_helpers.cpp
+    hle/service/kernel_helpers.h
     hle/service/lbl/lbl.cpp
     hle/service/lbl/lbl.h
     hle/service/ldn/lan_discovery.cpp
     hle/service/ldn/lan_discovery.h
-    hle/service/ldn/ldn_results.h
     hle/service/ldn/ldn.cpp
     hle/service/ldn/ldn.h
+    hle/service/ldn/ldn_results.h
     hle/service/ldn/ldn_types.h
     hle/service/ldr/ldr.cpp
     hle/service/ldr/ldr.h
@@ -563,16 +587,6 @@ add_library(core STATIC
     hle/service/lm/lm.h
     hle/service/mig/mig.cpp
     hle/service/mig/mig.h
-    hle/service/mii/types/char_info.cpp
-    hle/service/mii/types/char_info.h
-    hle/service/mii/types/core_data.cpp
-    hle/service/mii/types/core_data.h
-    hle/service/mii/types/raw_data.cpp
-    hle/service/mii/types/raw_data.h
-    hle/service/mii/types/store_data.cpp
-    hle/service/mii/types/store_data.h
-    hle/service/mii/types/ver3_store_data.cpp
-    hle/service/mii/types/ver3_store_data.h
     hle/service/mii/mii.cpp
     hle/service/mii/mii.h
     hle/service/mii/mii_database.cpp
@@ -584,10 +598,22 @@ add_library(core STATIC
     hle/service/mii/mii_result.h
     hle/service/mii/mii_types.h
     hle/service/mii/mii_util.h
+    hle/service/mii/types/char_info.cpp
+    hle/service/mii/types/char_info.h
+    hle/service/mii/types/core_data.cpp
+    hle/service/mii/types/core_data.h
+    hle/service/mii/types/raw_data.cpp
+    hle/service/mii/types/raw_data.h
+    hle/service/mii/types/store_data.cpp
+    hle/service/mii/types/store_data.h
+    hle/service/mii/types/ver3_store_data.cpp
+    hle/service/mii/types/ver3_store_data.h
     hle/service/mm/mm_u.cpp
     hle/service/mm/mm_u.h
     hle/service/mnpp/mnpp_app.cpp
     hle/service/mnpp/mnpp_app.h
+    hle/service/mutex.cpp
+    hle/service/mutex.h
     hle/service/ncm/ncm.cpp
     hle/service/ncm/ncm.h
     hle/service/nfc/common/amiibo_crypto.cpp
@@ -757,19 +783,12 @@ add_library(core STATIC
     hle/service/ptm/ptm.h
     hle/service/ptm/ts.cpp
     hle/service/ptm/ts.h
-    hle/service/hle_ipc.cpp
+    hle/service/ro/ro.cpp
-    hle/service/hle_ipc.h
+    hle/service/ro/ro.h
-    hle/service/ipc_helpers.h
-    hle/service/kernel_helpers.cpp
-    hle/service/kernel_helpers.h
-    hle/service/mutex.cpp
-    hle/service/mutex.h
     hle/service/ro/ro_nro_utils.cpp
     hle/service/ro/ro_nro_utils.h
     hle/service/ro/ro_results.h
     hle/service/ro/ro_types.h
-    hle/service/ro/ro.cpp
-    hle/service/ro/ro.h
     hle/service/server_manager.cpp
     hle/service/server_manager.h
     hle/service/service.cpp
@@ -836,9 +855,9 @@ add_library(core STATIC
     internal_network/network.h
     internal_network/network_interface.cpp
     internal_network/network_interface.h
-    internal_network/sockets.h
     internal_network/socket_proxy.cpp
     internal_network/socket_proxy.h
+    internal_network/sockets.h
     loader/deconstructed_rom_directory.cpp
     loader/deconstructed_rom_directory.h
     loader/kip.cpp
@@ -857,13 +876,13 @@ add_library(core STATIC
     loader/nsp.h
     loader/xci.cpp
     loader/xci.h
+    memory.cpp
+    memory.h
     memory/cheat_engine.cpp
     memory/cheat_engine.h
     memory/dmnt_cheat_types.h
     memory/dmnt_cheat_vm.cpp
     memory/dmnt_cheat_vm.h
-    memory.cpp
-    memory.h
     perf_stats.cpp
     perf_stats.h
     precompiled_headers.h

src/core/core.cpp

@@ -21,13 +21,13 @@
 #include "core/debugger/debugger.h"
 #include "core/device_memory.h"
 #include "core/file_sys/bis_factory.h"
-#include "core/file_sys/mode.h"
+#include "core/file_sys/fs_filesystem.h"
 #include "core/file_sys/patch_manager.h"
 #include "core/file_sys/registered_cache.h"
 #include "core/file_sys/romfs_factory.h"
 #include "core/file_sys/savedata_factory.h"
-#include "core/file_sys/vfs_concat.h"
+#include "core/file_sys/vfs/vfs_concat.h"
-#include "core/file_sys/vfs_real.h"
+#include "core/file_sys/vfs/vfs_real.h"
 #include "core/gpu_dirty_memory_manager.h"
 #include "core/hle/kernel/k_memory_manager.h"
 #include "core/hle/kernel/k_process.h"
@@ -102,7 +102,7 @@ FileSys::VirtualFile GetGameFileFromPath(const FileSys::VirtualFilesystem& vfs,
     Common::SplitPath(path, &dir_name, &filename, nullptr);
 
     if (filename == "00") {
-        const auto dir = vfs->OpenDirectory(dir_name, FileSys::Mode::Read);
+        const auto dir = vfs->OpenDirectory(dir_name, FileSys::OpenMode::Read);
         std::vector<FileSys::VirtualFile> concat;
 
         for (u32 i = 0; i < 0x10; ++i) {
@@ -127,10 +127,10 @@ FileSys::VirtualFile GetGameFileFromPath(const FileSys::VirtualFilesystem& vfs,
     }
 
     if (Common::FS::IsDir(path)) {
-        return vfs->OpenFile(path + "/main", FileSys::Mode::Read);
+        return vfs->OpenFile(path + "/main", FileSys::OpenMode::Read);
     }
 
-    return vfs->OpenFile(path, FileSys::Mode::Read);
+    return vfs->OpenFile(path, FileSys::OpenMode::Read);
 }
 
 struct System::Impl {

src/core/core.h

@@ -13,7 +13,7 @@
 #include <vector>
 
 #include "common/common_types.h"
-#include "core/file_sys/vfs_types.h"
+#include "core/file_sys/vfs/vfs_types.h"
 
 namespace Core::Frontend {
 class EmuWindow;

src/core/crypto/aes_util.h

@@ -7,7 +7,7 @@
 #include <span>
 #include <type_traits>
 #include "common/common_types.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 
 namespace Core::Crypto {
 

src/core/crypto/encryption_layer.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #include "common/common_types.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 
 namespace Core::Crypto {
 

src/core/crypto/partition_data_manager.cpp

@@ -21,9 +21,9 @@
 #include "core/crypto/partition_data_manager.h"
 #include "core/crypto/xts_encryption_layer.h"
 #include "core/file_sys/kernel_executable.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
-#include "core/file_sys/vfs_offset.h"
+#include "core/file_sys/vfs/vfs_offset.h"
-#include "core/file_sys/vfs_vector.h"
+#include "core/file_sys/vfs/vfs_vector.h"
 #include "core/loader/loader.h"
 
 using Common::AsArray;

src/core/crypto/partition_data_manager.h

@@ -5,7 +5,7 @@
 
 #include <vector>
 #include "common/common_types.h"
-#include "core/file_sys/vfs_types.h"
+#include "core/file_sys/vfs/vfs_types.h"
 
 namespace Core::Crypto {
 

src/core/file_sys/bis_factory.cpp

@@ -4,9 +4,8 @@
 #include <fmt/format.h>
 #include "common/fs/path_util.h"
 #include "core/file_sys/bis_factory.h"
-#include "core/file_sys/mode.h"
 #include "core/file_sys/registered_cache.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 
 namespace FileSys {
 
@@ -84,7 +83,7 @@ VirtualFile BISFactory::OpenPartitionStorage(BisPartitionId id,
                                              VirtualFilesystem file_system) const {
     auto& keys = Core::Crypto::KeyManager::Instance();
     Core::Crypto::PartitionDataManager pdm{file_system->OpenDirectory(
-        Common::FS::GetYuzuPathString(Common::FS::YuzuPath::NANDDir), Mode::Read)};
+        Common::FS::GetYuzuPathString(Common::FS::YuzuPath::NANDDir), OpenMode::Read)};
     keys.PopulateFromPartitionData(pdm);
 
     switch (id) {

src/core/file_sys/bis_factory.h

@@ -6,7 +6,7 @@
 #include <memory>
 
 #include "common/common_types.h"
-#include "core/file_sys/vfs_types.h"
+#include "core/file_sys/vfs/vfs_types.h"
 
 namespace FileSys {
 

src/core/file_sys/card_image.cpp

@@ -13,8 +13,8 @@
 #include "core/file_sys/nca_metadata.h"
 #include "core/file_sys/partition_filesystem.h"
 #include "core/file_sys/submission_package.h"
-#include "core/file_sys/vfs_offset.h"
+#include "core/file_sys/vfs/vfs_offset.h"
-#include "core/file_sys/vfs_vector.h"
+#include "core/file_sys/vfs/vfs_vector.h"
 #include "core/loader/loader.h"
 
 namespace FileSys {

src/core/file_sys/card_image.h

@@ -8,7 +8,7 @@
 #include <vector>
 #include "common/common_types.h"
 #include "common/swap.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 
 namespace Core::Crypto {
 class KeyManager;

src/core/file_sys/content_archive.cpp

@@ -13,7 +13,7 @@
 #include "core/crypto/key_manager.h"
 #include "core/file_sys/content_archive.h"
 #include "core/file_sys/partition_filesystem.h"
-#include "core/file_sys/vfs_offset.h"
+#include "core/file_sys/vfs/vfs_offset.h"
 #include "core/loader/loader.h"
 
 #include "core/file_sys/fssystem/fssystem_compression_configuration.h"

src/core/file_sys/content_archive.h

@@ -13,7 +13,7 @@
 #include "common/common_types.h"
 #include "common/swap.h"
 #include "core/crypto/key_manager.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 
 namespace Loader {
 enum class ResultStatus : u16;

src/core/file_sys/control_metadata.cpp

@@ -5,7 +5,7 @@
 #include "common/string_util.h"
 #include "common/swap.h"
 #include "core/file_sys/control_metadata.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 
 namespace FileSys {
 

src/core/file_sys/control_metadata.h

@@ -8,7 +8,7 @@
 #include "common/common_funcs.h"
 #include "common/common_types.h"
 #include "common/swap.h"
-#include "core/file_sys/vfs_types.h"
+#include "core/file_sys/vfs/vfs_types.h"
 
 namespace FileSys {
 

src/core/file_sys/errors.h

@@ -7,18 +7,13 @@
 
 namespace FileSys {
 
-constexpr Result ERROR_PATH_NOT_FOUND{ErrorModule::FS, 1};
+constexpr Result ResultPathNotFound{ErrorModule::FS, 1};
-constexpr Result ERROR_PATH_ALREADY_EXISTS{ErrorModule::FS, 2};
+constexpr Result ResultPathAlreadyExists{ErrorModule::FS, 2};
-constexpr Result ERROR_ENTITY_NOT_FOUND{ErrorModule::FS, 1002};
-constexpr Result ERROR_SD_CARD_NOT_FOUND{ErrorModule::FS, 2001};
-constexpr Result ERROR_OUT_OF_BOUNDS{ErrorModule::FS, 3005};
-constexpr Result ERROR_FAILED_MOUNT_ARCHIVE{ErrorModule::FS, 3223};
-constexpr Result ERROR_INVALID_ARGUMENT{ErrorModule::FS, 6001};
-constexpr Result ERROR_INVALID_OFFSET{ErrorModule::FS, 6061};
-constexpr Result ERROR_INVALID_SIZE{ErrorModule::FS, 6062};
-
 constexpr Result ResultUnsupportedSdkVersion{ErrorModule::FS, 50};
 constexpr Result ResultPartitionNotFound{ErrorModule::FS, 1001};
+constexpr Result ResultTargetNotFound{ErrorModule::FS, 1002};
+constexpr Result ResultPortSdCardNoDevice{ErrorModule::FS, 2001};
+constexpr Result ResultNotImplemented{ErrorModule::FS, 3001};
 constexpr Result ResultUnsupportedVersion{ErrorModule::FS, 3002};
 constexpr Result ResultOutOfRange{ErrorModule::FS, 3005};
 constexpr Result ResultAllocationMemoryFailedInFileSystemBuddyHeapA{ErrorModule::FS, 3294};
@@ -78,10 +73,21 @@ constexpr Result ResultUnexpectedInCompressedStorageA{ErrorModule::FS, 5324};
 constexpr Result ResultUnexpectedInCompressedStorageB{ErrorModule::FS, 5325};
 constexpr Result ResultUnexpectedInCompressedStorageC{ErrorModule::FS, 5326};
 constexpr Result ResultUnexpectedInCompressedStorageD{ErrorModule::FS, 5327};
+constexpr Result ResultUnexpectedInPathA{ErrorModule::FS, 5328};
 constexpr Result ResultInvalidArgument{ErrorModule::FS, 6001};
+constexpr Result ResultInvalidPath{ErrorModule::FS, 6002};
+constexpr Result ResultTooLongPath{ErrorModule::FS, 6003};
+constexpr Result ResultInvalidCharacter{ErrorModule::FS, 6004};
+constexpr Result ResultInvalidPathFormat{ErrorModule::FS, 6005};
+constexpr Result ResultDirectoryUnobtainable{ErrorModule::FS, 6006};
+constexpr Result ResultNotNormalized{ErrorModule::FS, 6007};
 constexpr Result ResultInvalidOffset{ErrorModule::FS, 6061};
 constexpr Result ResultInvalidSize{ErrorModule::FS, 6062};
 constexpr Result ResultNullptrArgument{ErrorModule::FS, 6063};
+constexpr Result ResultInvalidOpenMode{ErrorModule::FS, 6072};
+constexpr Result ResultFileExtensionWithoutOpenModeAllowAppend{ErrorModule::FS, 6201};
+constexpr Result ResultReadNotPermitted{ErrorModule::FS, 6202};
+constexpr Result ResultWriteNotPermitted{ErrorModule::FS, 6203};
 constexpr Result ResultUnsupportedSetSizeForIndirectStorage{ErrorModule::FS, 6325};
 constexpr Result ResultUnsupportedWriteForCompressedStorage{ErrorModule::FS, 6387};
 constexpr Result ResultUnsupportedOperateRangeForCompressedStorage{ErrorModule::FS, 6388};

src/core/file_sys/fs_directory.h

@@ -0,0 +1,33 @@
+// SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+namespace FileSys {
+
+constexpr inline size_t EntryNameLengthMax = 0x300;
+
+struct DirectoryEntry {
+    DirectoryEntry(std::string_view view, s8 entry_type, u64 entry_size)
+        : type{entry_type}, file_size{static_cast<s64>(entry_size)} {
+        const std::size_t copy_size = view.copy(name, std::size(name) - 1);
+        name[copy_size] = '\0';
+    }
+
+    char name[EntryNameLengthMax + 1];
+    INSERT_PADDING_BYTES(3);
+    s8 type;
+    INSERT_PADDING_BYTES(3);
+    s64 file_size;
+};
+
+static_assert(sizeof(DirectoryEntry) == 0x310,
+              "Directory Entry struct isn't exactly 0x310 bytes long!");
+static_assert(offsetof(DirectoryEntry, type) == 0x304, "Wrong offset for type in Entry.");
+static_assert(offsetof(DirectoryEntry, file_size) == 0x308, "Wrong offset for file_size in Entry.");
+
+struct DirectoryHandle {
+    void* handle;
+};
+
+} // namespace FileSys

src/core/file_sys/fs_file.h

@@ -0,0 +1,65 @@
+// SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "common/common_types.h"
+
+namespace FileSys {
+
+struct ReadOption {
+    u32 value;
+
+    static const ReadOption None;
+};
+
+enum ReadOptionFlag : u32 {
+    ReadOptionFlag_None = (0 << 0),
+};
+
+inline constexpr const ReadOption ReadOption::None = {ReadOptionFlag_None};
+
+inline constexpr bool operator==(const ReadOption& lhs, const ReadOption& rhs) {
+    return lhs.value == rhs.value;
+}
+
+inline constexpr bool operator!=(const ReadOption& lhs, const ReadOption& rhs) {
+    return !(lhs == rhs);
+}
+
+static_assert(sizeof(ReadOption) == sizeof(u32));
+
+enum WriteOptionFlag : u32 {
+    WriteOptionFlag_None = (0 << 0),
+    WriteOptionFlag_Flush = (1 << 0),
+};
+
+struct WriteOption {
+    u32 value;
+
+    constexpr inline bool HasFlushFlag() const {
+        return value & WriteOptionFlag_Flush;
+    }
+
+    static const WriteOption None;
+    static const WriteOption Flush;
+};
+
+inline constexpr const WriteOption WriteOption::None = {WriteOptionFlag_None};
+inline constexpr const WriteOption WriteOption::Flush = {WriteOptionFlag_Flush};
+
+inline constexpr bool operator==(const WriteOption& lhs, const WriteOption& rhs) {
+    return lhs.value == rhs.value;
+}
+
+inline constexpr bool operator!=(const WriteOption& lhs, const WriteOption& rhs) {
+    return !(lhs == rhs);
+}
+
+static_assert(sizeof(WriteOption) == sizeof(u32));
+
+struct FileHandle {
+    void* handle;
+};
+
+} // namespace FileSys

src/core/file_sys/fs_filesystem.h

@@ -0,0 +1,39 @@
+// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "common/common_funcs.h"
+#include "common/common_types.h"
+
+namespace FileSys {
+
+enum class OpenMode : u32 {
+    Read = (1 << 0),
+    Write = (1 << 1),
+    AllowAppend = (1 << 2),
+
+    ReadWrite = (Read | Write),
+    All = (ReadWrite | AllowAppend),
+};
+DECLARE_ENUM_FLAG_OPERATORS(OpenMode)
+
+enum class OpenDirectoryMode : u64 {
+    Directory = (1 << 0),
+    File = (1 << 1),
+
+    All = (Directory | File),
+};
+DECLARE_ENUM_FLAG_OPERATORS(OpenDirectoryMode)
+
+enum class DirectoryEntryType : u8 {
+    Directory = 0,
+    File = 1,
+};
+
+enum class CreateOption : u8 {
+    None = (0 << 0),
+    BigFile = (1 << 0),
+};
+
+} // namespace FileSys

src/core/file_sys/fs_memory_management.h

@@ -0,0 +1,40 @@
+// SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <mutex>
+#include "common/alignment.h"
+
+namespace FileSys {
+
+constexpr size_t RequiredAlignment = alignof(u64);
+
+void* AllocateUnsafe(size_t size) {
+    // Allocate
+    void* const ptr = ::operator new(size, std::align_val_t{RequiredAlignment});
+
+    // Check alignment
+    ASSERT(Common::IsAligned(reinterpret_cast<uintptr_t>(ptr), RequiredAlignment));
+
+    // Return allocated pointer
+    return ptr;
+}
+
+void DeallocateUnsafe(void* ptr, size_t size) {
+    // Deallocate the pointer
+    ::operator delete(ptr, std::align_val_t{RequiredAlignment});
+}
+
+void* Allocate(size_t size) {
+    return AllocateUnsafe(size);
+}
+
+void Deallocate(void* ptr, size_t size) {
+    // If the pointer is non-null, deallocate it
+    if (ptr != nullptr) {
+        DeallocateUnsafe(ptr, size);
+    }
+}
+
+} // namespace FileSys

src/core/file_sys/fs_operate_range.h

@@ -0,0 +1,22 @@
+// SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "common/common_types.h"
+
+namespace FileSys {
+
+enum class OperationId : s64 {
+    FillZero = 0,
+    DestroySignature = 1,
+    Invalidate = 2,
+    QueryRange = 3,
+    QueryUnpreparedRange = 4,
+    QueryLazyLoadCompletionRate = 5,
+    SetLazyLoadPriority = 6,
+
+    ReadLazyLoadFileForciblyForDebug = 10001,
+};
+
+} // namespace FileSys

src/core/file_sys/fs_path.h

@@ -0,0 +1,566 @@
+// SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "common/alignment.h"
+#include "common/common_funcs.h"
+#include "core/file_sys/errors.h"
+#include "core/file_sys/fs_memory_management.h"
+#include "core/file_sys/fs_path_utility.h"
+#include "core/file_sys/fs_string_util.h"
+#include "core/hle/result.h"
+
+namespace FileSys {
+class DirectoryPathParser;
+
+class Path {
+    YUZU_NON_COPYABLE(Path);
+    YUZU_NON_MOVEABLE(Path);
+
+private:
+    static constexpr const char* EmptyPath = "";
+    static constexpr size_t WriteBufferAlignmentLength = 8;
+
+private:
+    friend class DirectoryPathParser;
+
+public:
+    class WriteBuffer {
+        YUZU_NON_COPYABLE(WriteBuffer);
+
+    private:
+        char* m_buffer;
+        size_t m_length_and_is_normalized;
+
+    public:
+        constexpr WriteBuffer() : m_buffer(nullptr), m_length_and_is_normalized(0) {}
+
+        constexpr ~WriteBuffer() {
+            if (m_buffer != nullptr) {
+                Deallocate(m_buffer, this->GetLength());
+                this->ResetBuffer();
+            }
+        }
+
+        constexpr WriteBuffer(WriteBuffer&& rhs)
+            : m_buffer(rhs.m_buffer), m_length_and_is_normalized(rhs.m_length_and_is_normalized) {
+            rhs.ResetBuffer();
+        }
+
+        constexpr WriteBuffer& operator=(WriteBuffer&& rhs) {
+            if (m_buffer != nullptr) {
+                Deallocate(m_buffer, this->GetLength());
+            }
+
+            m_buffer = rhs.m_buffer;
+            m_length_and_is_normalized = rhs.m_length_and_is_normalized;
+
+            rhs.ResetBuffer();
+
+            return *this;
+        }
+
+        constexpr void ResetBuffer() {
+            m_buffer = nullptr;
+            this->SetLength(0);
+        }
+
+        constexpr char* Get() const {
+            return m_buffer;
+        }
+
+        constexpr size_t GetLength() const {
+            return m_length_and_is_normalized >> 1;
+        }
+
+        constexpr bool IsNormalized() const {
+            return static_cast<bool>(m_length_and_is_normalized & 1);
+        }
+
+        constexpr void SetNormalized() {
+            m_length_and_is_normalized |= static_cast<size_t>(1);
+        }
+
+        constexpr void SetNotNormalized() {
+            m_length_and_is_normalized &= ~static_cast<size_t>(1);
+        }
+
+    private:
+        constexpr WriteBuffer(char* buffer, size_t length)
+            : m_buffer(buffer), m_length_and_is_normalized(0) {
+            this->SetLength(length);
+        }
+
+    public:
+        static WriteBuffer Make(size_t length) {
+            if (void* alloc = Allocate(length); alloc != nullptr) {
+                return WriteBuffer(static_cast<char*>(alloc), length);
+            } else {
+                return WriteBuffer();
+            }
+        }
+
+    private:
+        constexpr void SetLength(size_t size) {
+            m_length_and_is_normalized = (m_length_and_is_normalized & 1) | (size << 1);
+        }
+    };
+
+private:
+    const char* m_str;
+    WriteBuffer m_write_buffer;
+
+public:
+    constexpr Path() : m_str(EmptyPath), m_write_buffer() {}
+
+    constexpr Path(const char* s) : m_str(s), m_write_buffer() {
+        m_write_buffer.SetNormalized();
+    }
+
+    constexpr ~Path() = default;
+
+    constexpr Result SetShallowBuffer(const char* buffer) {
+        // Check pre-conditions
+        ASSERT(m_write_buffer.GetLength() == 0);
+
+        // Check the buffer is valid
+        R_UNLESS(buffer != nullptr, ResultNullptrArgument);
+
+        // Set buffer
+        this->SetReadOnlyBuffer(buffer);
+
+        // Note that we're normalized
+        this->SetNormalized();
+
+        R_SUCCEED();
+    }
+
+    constexpr const char* GetString() const {
+        // Check pre-conditions
+        ASSERT(this->IsNormalized());
+
+        return m_str;
+    }
+
+    constexpr size_t GetLength() const {
+        if (std::is_constant_evaluated()) {
+            return Strlen(this->GetString());
+        } else {
+            return std::strlen(this->GetString());
+        }
+    }
+
+    constexpr bool IsEmpty() const {
+        return *m_str == '\x00';
+    }
+
+    constexpr bool IsMatchHead(const char* p, size_t len) const {
+        return Strncmp(this->GetString(), p, len) == 0;
+    }
+
+    Result Initialize(const Path& rhs) {
+        // Check the other path is normalized
+        const bool normalized = rhs.IsNormalized();
+        R_UNLESS(normalized, ResultNotNormalized);
+
+        // Allocate buffer for our path
+        const auto len = rhs.GetLength();
+        R_TRY(this->Preallocate(len + 1));
+
+        // Copy the path
+        const size_t copied = Strlcpy<char>(m_write_buffer.Get(), rhs.GetString(), len + 1);
+        R_UNLESS(copied == len, ResultUnexpectedInPathA);
+
+        // Set normalized
+        this->SetNormalized();
+        R_SUCCEED();
+    }
+
+    Result Initialize(const char* path, size_t len) {
+        // Check the path is valid
+        R_UNLESS(path != nullptr, ResultNullptrArgument);
+
+        // Initialize
+        R_TRY(this->InitializeImpl(path, len));
+
+        // Set not normalized
+        this->SetNotNormalized();
+
+        R_SUCCEED();
+    }
+
+    Result Initialize(const char* path) {
+        // Check the path is valid
+        R_UNLESS(path != nullptr, ResultNullptrArgument);
+
+        R_RETURN(this->Initialize(path, std::strlen(path)));
+    }
+
+    Result InitializeWithReplaceBackslash(const char* path) {
+        // Check the path is valid
+        R_UNLESS(path != nullptr, ResultNullptrArgument);
+
+        // Initialize
+        R_TRY(this->InitializeImpl(path, std::strlen(path)));
+
+        // Replace slashes as desired
+        if (const auto write_buffer_length = m_write_buffer.GetLength(); write_buffer_length > 1) {
+            Replace(m_write_buffer.Get(), write_buffer_length - 1, '\\', '/');
+        }
+
+        // Set not normalized
+        this->SetNotNormalized();
+
+        R_SUCCEED();
+    }
+
+    Result InitializeWithReplaceForwardSlashes(const char* path) {
+        // Check the path is valid
+        R_UNLESS(path != nullptr, ResultNullptrArgument);
+
+        // Initialize
+        R_TRY(this->InitializeImpl(path, std::strlen(path)));
+
+        // Replace slashes as desired
+        if (m_write_buffer.GetLength() > 1) {
+            if (auto* p = m_write_buffer.Get(); p[0] == '/' && p[1] == '/') {
+                p[0] = '\\';
+                p[1] = '\\';
+            }
+        }
+
+        // Set not normalized
+        this->SetNotNormalized();
+
+        R_SUCCEED();
+    }
+
+    Result InitializeWithNormalization(const char* path, size_t size) {
+        // Check the path is valid
+        R_UNLESS(path != nullptr, ResultNullptrArgument);
+
+        // Initialize
+        R_TRY(this->InitializeImpl(path, size));
+
+        // Set not normalized
+        this->SetNotNormalized();
+
+        // Perform normalization
+        PathFlags path_flags;
+        if (IsPathRelative(m_str)) {
+            path_flags.AllowRelativePath();
+        } else if (IsWindowsPath(m_str, true)) {
+            path_flags.AllowWindowsPath();
+        } else {
+            /* NOTE: In this case, Nintendo checks is normalized, then sets is normalized, then
+             * returns success. */
+            /* This seems like a bug. */
+            size_t dummy;
+            bool normalized;
+            R_TRY(PathFormatter::IsNormalized(std::addressof(normalized), std::addressof(dummy),
+                                              m_str));
+
+            this->SetNormalized();
+            R_SUCCEED();
+        }
+
+        // Normalize
+        R_TRY(this->Normalize(path_flags));
+
+        this->SetNormalized();
+        R_SUCCEED();
+    }
+
+    Result InitializeWithNormalization(const char* path) {
+        // Check the path is valid
+        R_UNLESS(path != nullptr, ResultNullptrArgument);
+
+        R_RETURN(this->InitializeWithNormalization(path, std::strlen(path)));
+    }
+
+    Result InitializeAsEmpty() {
+        // Clear our buffer
+        this->ClearBuffer();
+
+        // Set normalized
+        this->SetNormalized();
+
+        R_SUCCEED();
+    }
+
+    Result AppendChild(const char* child) {
+        // Check the path is valid
+        R_UNLESS(child != nullptr, ResultNullptrArgument);
+
+        // Basic checks. If we have a path and the child is empty, we have nothing to do
+        const char* c = child;
+        if (m_str[0]) {
+            // Skip an early separator
+            if (*c == '/') {
+                ++c;
+            }
+
+            R_SUCCEED_IF(*c == '\x00');
+        }
+
+        // If we don't have a string, we can just initialize
+        auto cur_len = std::strlen(m_str);
+        if (cur_len == 0) {
+            R_RETURN(this->Initialize(child));
+        }
+
+        // Remove a trailing separator
+        if (m_str[cur_len - 1] == '/' || m_str[cur_len - 1] == '\\') {
+            --cur_len;
+        }
+
+        // Get the child path's length
+        auto child_len = std::strlen(c);
+
+        // Reset our write buffer
+        WriteBuffer old_write_buffer;
+        if (m_write_buffer.Get() != nullptr) {
+            old_write_buffer = std::move(m_write_buffer);
+            this->ClearBuffer();
+        }
+
+        // Pre-allocate the new buffer
+        R_TRY(this->Preallocate(cur_len + 1 + child_len + 1));
+
+        // Get our write buffer
+        auto* dst = m_write_buffer.Get();
+        if (old_write_buffer.Get() != nullptr && cur_len > 0) {
+            Strlcpy<char>(dst, old_write_buffer.Get(), cur_len + 1);
+        }
+
+        // Add separator
+        dst[cur_len] = '/';
+
+        // Copy the child path
+        const size_t copied = Strlcpy<char>(dst + cur_len + 1, c, child_len + 1);
+        R_UNLESS(copied == child_len, ResultUnexpectedInPathA);
+
+        R_SUCCEED();
+    }
+
+    Result AppendChild(const Path& rhs) {
+        R_RETURN(this->AppendChild(rhs.GetString()));
+    }
+
+    Result Combine(const Path& parent, const Path& child) {
+        // Get the lengths
+        const auto p_len = parent.GetLength();
+        const auto c_len = child.GetLength();
+
+        // Allocate our buffer
+        R_TRY(this->Preallocate(p_len + c_len + 1));
+
+        // Initialize as parent
+        R_TRY(this->Initialize(parent));
+
+        // If we're empty, we can just initialize as child
+        if (this->IsEmpty()) {
+            R_TRY(this->Initialize(child));
+        } else {
+            // Otherwise, we should append the child
+            R_TRY(this->AppendChild(child));
+        }
+
+        R_SUCCEED();
+    }
+
+    Result RemoveChild() {
+        // If we don't have a write-buffer, ensure that we have one
+        if (m_write_buffer.Get() == nullptr) {
+            if (const auto len = std::strlen(m_str); len > 0) {
+                R_TRY(this->Preallocate(len));
+                Strlcpy<char>(m_write_buffer.Get(), m_str, len + 1);
+            }
+        }
+
+        // Check that it's possible for us to remove a child
+        auto* p = m_write_buffer.Get();
+        s32 len = std::strlen(p);
+        R_UNLESS(len != 1 || (p[0] != '/' && p[0] != '.'), ResultNotImplemented);
+
+        // Handle a trailing separator
+        if (len > 0 && (p[len - 1] == '\\' || p[len - 1] == '/')) {
+            --len;
+        }
+
+        // Remove the child path segment
+        while ((--len) >= 0 && p[len]) {
+            if (p[len] == '/' || p[len] == '\\') {
+                if (len > 0) {
+                    p[len] = 0;
+                } else {
+                    p[1] = 0;
+                    len = 1;
+                }
+                break;
+            }
+        }
+
+        // Check that length remains > 0
+        R_UNLESS(len > 0, ResultNotImplemented);
+
+        R_SUCCEED();
+    }
+
+    Result Normalize(const PathFlags& flags) {
+        // If we're already normalized, nothing to do
+        R_SUCCEED_IF(this->IsNormalized());
+
+        // Check if we're normalized
+        bool normalized;
+        size_t dummy;
+        R_TRY(PathFormatter::IsNormalized(std::addressof(normalized), std::addressof(dummy), m_str,
+                                          flags));
+
+        // If we're not normalized, normalize
+        if (!normalized) {
+            // Determine necessary buffer length
+            auto len = m_write_buffer.GetLength();
+            if (flags.IsRelativePathAllowed() && IsPathRelative(m_str)) {
+                len += 2;
+            }
+            if (flags.IsWindowsPathAllowed() && IsWindowsPath(m_str, true)) {
+                len += 1;
+            }
+
+            // Allocate a new buffer
+            const size_t size = Common::AlignUp(len, WriteBufferAlignmentLength);
+            auto buf = WriteBuffer::Make(size);
+            R_UNLESS(buf.Get() != nullptr, ResultAllocationMemoryFailedMakeUnique);
+
+            // Normalize into it
+            R_TRY(PathFormatter::Normalize(buf.Get(), size, m_write_buffer.Get(),
+                                           m_write_buffer.GetLength(), flags));
+
+            // Set the normalized buffer as our buffer
+            this->SetModifiableBuffer(std::move(buf));
+        }
+
+        // Set normalized
+        this->SetNormalized();
+        R_SUCCEED();
+    }
+
+private:
+    void ClearBuffer() {
+        m_write_buffer.ResetBuffer();
+        m_str = EmptyPath;
+    }
+
+    void SetModifiableBuffer(WriteBuffer&& buffer) {
+        // Check pre-conditions
+        ASSERT(buffer.Get() != nullptr);
+        ASSERT(buffer.GetLength() > 0);
+        ASSERT(Common::IsAligned(buffer.GetLength(), WriteBufferAlignmentLength));
+
+        // Get whether we're normalized
+        if (m_write_buffer.IsNormalized()) {
+            buffer.SetNormalized();
+        } else {
+            buffer.SetNotNormalized();
+        }
+
+        // Set write buffer
+        m_write_buffer = std::move(buffer);
+        m_str = m_write_buffer.Get();
+    }
+
+    constexpr void SetReadOnlyBuffer(const char* buffer) {
+        m_str = buffer;
+        m_write_buffer.ResetBuffer();
+    }
+
+    Result Preallocate(size_t length) {
+        // Allocate additional space, if needed
+        if (length > m_write_buffer.GetLength()) {
+            // Allocate buffer
+            const size_t size = Common::AlignUp(length, WriteBufferAlignmentLength);
+            auto buf = WriteBuffer::Make(size);
+            R_UNLESS(buf.Get() != nullptr, ResultAllocationMemoryFailedMakeUnique);
+
+            // Set write buffer
+            this->SetModifiableBuffer(std::move(buf));
+        }
+
+        R_SUCCEED();
+    }
+
+    Result InitializeImpl(const char* path, size_t size) {
+        if (size > 0 && path[0]) {
+            // Pre allocate a buffer for the path
+            R_TRY(this->Preallocate(size + 1));
+
+            // Copy the path
+            const size_t copied = Strlcpy<char>(m_write_buffer.Get(), path, size + 1);
+            R_UNLESS(copied >= size, ResultUnexpectedInPathA);
+        } else {
+            // We can just clear the buffer
+            this->ClearBuffer();
+        }
+
+        R_SUCCEED();
+    }
+
+    constexpr char* GetWriteBuffer() {
+        ASSERT(m_write_buffer.Get() != nullptr);
+        return m_write_buffer.Get();
+    }
+
+    constexpr size_t GetWriteBufferLength() const {
+        return m_write_buffer.GetLength();
+    }
+
+    constexpr bool IsNormalized() const {
+        return m_write_buffer.IsNormalized();
+    }
+
+    constexpr void SetNormalized() {
+        m_write_buffer.SetNormalized();
+    }
+
+    constexpr void SetNotNormalized() {
+        m_write_buffer.SetNotNormalized();
+    }
+
+public:
+    bool operator==(const FileSys::Path& rhs) const {
+        return std::strcmp(this->GetString(), rhs.GetString()) == 0;
+    }
+    bool operator!=(const FileSys::Path& rhs) const {
+        return !(*this == rhs);
+    }
+    bool operator==(const char* p) const {
+        return std::strcmp(this->GetString(), p) == 0;
+    }
+    bool operator!=(const char* p) const {
+        return !(*this == p);
+    }
+};
+
+inline Result SetUpFixedPath(FileSys::Path* out, const char* s) {
+    // Verify the path is normalized
+    bool normalized;
+    size_t dummy;
+    R_TRY(PathNormalizer::IsNormalized(std::addressof(normalized), std::addressof(dummy), s));
+
+    R_UNLESS(normalized, ResultInvalidPathFormat);
+
+    // Set the fixed path
+    R_RETURN(out->SetShallowBuffer(s));
+}
+
+constexpr inline bool IsWindowsDriveRootPath(const FileSys::Path& path) {
+    const char* const str = path.GetString();
+    return IsWindowsDrive(str) &&
+           (str[2] == StringTraits::DirectorySeparator ||
+            str[2] == StringTraits::AlternateDirectorySeparator) &&
+           str[3] == StringTraits::NullTerminator;
+}
+
+} // namespace FileSys

src/core/file_sys/fs_string_util.h

@@ -0,0 +1,226 @@
+// SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "common/assert.h"
+
+namespace FileSys {
+
+template <typename T>
+constexpr int Strlen(const T* str) {
+    ASSERT(str != nullptr);
+
+    int length = 0;
+    while (*str++) {
+        ++length;
+    }
+
+    return length;
+}
+
+template <typename T>
+constexpr int Strnlen(const T* str, int count) {
+    ASSERT(str != nullptr);
+    ASSERT(count >= 0);
+
+    int length = 0;
+    while (count-- && *str++) {
+        ++length;
+    }
+
+    return length;
+}
+
+template <typename T>
+constexpr int Strncmp(const T* lhs, const T* rhs, int count) {
+    ASSERT(lhs != nullptr);
+    ASSERT(rhs != nullptr);
+    ASSERT(count >= 0);
+
+    if (count == 0) {
+        return 0;
+    }
+
+    T l, r;
+    do {
+        l = *(lhs++);
+        r = *(rhs++);
+    } while (l && (l == r) && (--count));
+
+    return l - r;
+}
+
+template <typename T>
+static constexpr int Strlcpy(T* dst, const T* src, int count) {
+    ASSERT(dst != nullptr);
+    ASSERT(src != nullptr);
+
+    const T* cur = src;
+    if (count > 0) {
+        while ((--count) && *cur) {
+            *(dst++) = *(cur++);
+        }
+        *dst = 0;
+    }
+
+    while (*cur) {
+        cur++;
+    }
+
+    return static_cast<int>(cur - src);
+}
+
+enum CharacterEncodingResult {
+    CharacterEncodingResult_Success = 0,
+    CharacterEncodingResult_InsufficientLength = 1,
+    CharacterEncodingResult_InvalidFormat = 2,
+};
+
+namespace impl {
+
+class CharacterEncodingHelper {
+public:
+    static constexpr int8_t Utf8NBytesInnerTable[0x100 + 1] = {
+        -1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+        1,  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+        1,  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+        1,  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+        1,  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+        2,  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3,
+        3,  3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 7, 8,
+    };
+
+    static constexpr char GetUtf8NBytes(size_t i) {
+        return static_cast<char>(Utf8NBytesInnerTable[1 + i]);
+    }
+};
+
+} // namespace impl
+
+constexpr inline CharacterEncodingResult ConvertCharacterUtf8ToUtf32(u32* dst, const char* src) {
+    // Check pre-conditions
+    ASSERT(dst != nullptr);
+    ASSERT(src != nullptr);
+
+    // Perform the conversion
+    const auto* p = src;
+    switch (impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[0]))) {
+    case 1:
+        *dst = static_cast<u32>(p[0]);
+        return CharacterEncodingResult_Success;
+    case 2:
+        if ((static_cast<u32>(p[0]) & 0x1E) != 0) {
+            if (impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[1])) ==
+                0) {
+                *dst = (static_cast<u32>(p[0] & 0x1F) << 6) | (static_cast<u32>(p[1] & 0x3F) << 0);
+                return CharacterEncodingResult_Success;
+            }
+        }
+        break;
+    case 3:
+        if (impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[1])) == 0 &&
+            impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[2])) == 0) {
+            const u32 c = (static_cast<u32>(p[0] & 0xF) << 12) |
+                          (static_cast<u32>(p[1] & 0x3F) << 6) |
+                          (static_cast<u32>(p[2] & 0x3F) << 0);
+            if ((c & 0xF800) != 0 && (c & 0xF800) != 0xD800) {
+                *dst = c;
+                return CharacterEncodingResult_Success;
+            }
+        }
+        return CharacterEncodingResult_InvalidFormat;
+    case 4:
+        if (impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[1])) == 0 &&
+            impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[2])) == 0 &&
+            impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[3])) == 0) {
+            const u32 c =
+                (static_cast<u32>(p[0] & 0x7) << 18) | (static_cast<u32>(p[1] & 0x3F) << 12) |
+                (static_cast<u32>(p[2] & 0x3F) << 6) | (static_cast<u32>(p[3] & 0x3F) << 0);
+            if (c >= 0x10000 && c < 0x110000) {
+                *dst = c;
+                return CharacterEncodingResult_Success;
+            }
+        }
+        return CharacterEncodingResult_InvalidFormat;
+    default:
+        break;
+    }
+
+    // We failed to convert
+    return CharacterEncodingResult_InvalidFormat;
+}
+
+constexpr inline CharacterEncodingResult PickOutCharacterFromUtf8String(char* dst,
+                                                                        const char** str) {
+    // Check pre-conditions
+    ASSERT(dst != nullptr);
+    ASSERT(str != nullptr);
+    ASSERT(*str != nullptr);
+
+    // Clear the output
+    dst[0] = 0;
+    dst[1] = 0;
+    dst[2] = 0;
+    dst[3] = 0;
+
+    // Perform the conversion
+    const auto* p = *str;
+    u32 c = static_cast<u32>(*p);
+    switch (impl::CharacterEncodingHelper::GetUtf8NBytes(c)) {
+    case 1:
+        dst[0] = (*str)[0];
+        ++(*str);
+        break;
+    case 2:
+        if ((p[0] & 0x1E) != 0) {
+            if (impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[1])) ==
+                0) {
+                c = (static_cast<u32>(p[0] & 0x1F) << 6) | (static_cast<u32>(p[1] & 0x3F) << 0);
+                dst[0] = (*str)[0];
+                dst[1] = (*str)[1];
+                (*str) += 2;
+                break;
+            }
+        }
+        return CharacterEncodingResult_InvalidFormat;
+    case 3:
+        if (impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[1])) == 0 &&
+            impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[2])) == 0) {
+            c = (static_cast<u32>(p[0] & 0xF) << 12) | (static_cast<u32>(p[1] & 0x3F) << 6) |
+                (static_cast<u32>(p[2] & 0x3F) << 0);
+            if ((c & 0xF800) != 0 && (c & 0xF800) != 0xD800) {
+                dst[0] = (*str)[0];
+                dst[1] = (*str)[1];
+                dst[2] = (*str)[2];
+                (*str) += 3;
+                break;
+            }
+        }
+        return CharacterEncodingResult_InvalidFormat;
+    case 4:
+        if (impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[1])) == 0 &&
+            impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[2])) == 0 &&
+            impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[3])) == 0) {
+            c = (static_cast<u32>(p[0] & 0x7) << 18) | (static_cast<u32>(p[1] & 0x3F) << 12) |
+                (static_cast<u32>(p[2] & 0x3F) << 6) | (static_cast<u32>(p[3] & 0x3F) << 0);
+            if (c >= 0x10000 && c < 0x110000) {
+                dst[0] = (*str)[0];
+                dst[1] = (*str)[1];
+                dst[2] = (*str)[2];
+                dst[3] = (*str)[3];
+                (*str) += 4;
+                break;
+            }
+        }
+        return CharacterEncodingResult_InvalidFormat;
+    default:
+        return CharacterEncodingResult_InvalidFormat;
+    }
+
+    return CharacterEncodingResult_Success;
+}
+
+} // namespace FileSys

src/core/file_sys/fsmitm_romfsbuild.cpp

@@ -8,8 +8,8 @@
 #include "common/assert.h"
 #include "core/file_sys/fsmitm_romfsbuild.h"
 #include "core/file_sys/ips_layer.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
-#include "core/file_sys/vfs_vector.h"
+#include "core/file_sys/vfs/vfs_vector.h"
 
 namespace FileSys {
 

src/core/file_sys/fsmitm_romfsbuild.h

@@ -7,7 +7,7 @@
 #include <memory>
 #include <string>
 #include "common/common_types.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 
 namespace FileSys {
 

src/core/file_sys/fssystem/fs_i_storage.h

@@ -5,7 +5,7 @@
 
 #include "common/overflow.h"
 #include "core/file_sys/errors.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 
 namespace FileSys {
 

src/core/file_sys/fssystem/fssystem_aes_ctr_counter_extended_storage.cpp

@@ -4,7 +4,7 @@
 #include "core/file_sys/fssystem/fssystem_aes_ctr_counter_extended_storage.h"
 #include "core/file_sys/fssystem/fssystem_aes_ctr_storage.h"
 #include "core/file_sys/fssystem/fssystem_nca_header.h"
-#include "core/file_sys/vfs_offset.h"
+#include "core/file_sys/vfs/vfs_offset.h"
 
 namespace FileSys {
 

src/core/file_sys/fssystem/fssystem_aes_ctr_storage.h

@@ -9,7 +9,7 @@
 #include "core/crypto/key_manager.h"
 #include "core/file_sys/errors.h"
 #include "core/file_sys/fssystem/fs_i_storage.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 
 namespace FileSys {
 

src/core/file_sys/fssystem/fssystem_bucket_tree.h

@@ -10,7 +10,7 @@
 #include "common/common_types.h"
 #include "common/literals.h"
 
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 #include "core/hle/result.h"
 
 namespace FileSys {

src/core/file_sys/fssystem/fssystem_compressed_storage.h

@@ -10,7 +10,7 @@
 #include "core/file_sys/fssystem/fssystem_bucket_tree.h"
 #include "core/file_sys/fssystem/fssystem_compression_common.h"
 #include "core/file_sys/fssystem/fssystem_pooled_buffer.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 
 namespace FileSys {
 

src/core/file_sys/fssystem/fssystem_hierarchical_integrity_verification_storage.cpp

@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #include "core/file_sys/fssystem/fssystem_hierarchical_integrity_verification_storage.h"
-#include "core/file_sys/vfs_offset.h"
+#include "core/file_sys/vfs/vfs_offset.h"
 
 namespace FileSys {
 

src/core/file_sys/fssystem/fssystem_hierarchical_integrity_verification_storage.h

@@ -8,7 +8,7 @@
 #include "core/file_sys/fssystem/fs_types.h"
 #include "core/file_sys/fssystem/fssystem_alignment_matching_storage.h"
 #include "core/file_sys/fssystem/fssystem_integrity_verification_storage.h"
-#include "core/file_sys/vfs_offset.h"
+#include "core/file_sys/vfs/vfs_offset.h"
 
 namespace FileSys {
 

src/core/file_sys/fssystem/fssystem_hierarchical_sha256_storage.h

@@ -7,7 +7,7 @@
 
 #include "core/file_sys/errors.h"
 #include "core/file_sys/fssystem/fs_i_storage.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 
 namespace FileSys {
 

src/core/file_sys/fssystem/fssystem_indirect_storage.h

@@ -7,8 +7,8 @@
 #include "core/file_sys/fssystem/fs_i_storage.h"
 #include "core/file_sys/fssystem/fssystem_bucket_tree.h"
 #include "core/file_sys/fssystem/fssystem_bucket_tree_template_impl.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
-#include "core/file_sys/vfs_offset.h"
+#include "core/file_sys/vfs/vfs_offset.h"
 
 namespace FileSys {
 

src/core/file_sys/fssystem/fssystem_integrity_romfs_storage.h

@@ -5,7 +5,7 @@
 
 #include "core/file_sys/fssystem/fssystem_hierarchical_integrity_verification_storage.h"
 #include "core/file_sys/fssystem/fssystem_nca_header.h"
-#include "core/file_sys/vfs_vector.h"
+#include "core/file_sys/vfs/vfs_vector.h"
 
 namespace FileSys {
 

src/core/file_sys/fssystem/fssystem_nca_file_system_driver.cpp

@@ -14,8 +14,8 @@
 #include "core/file_sys/fssystem/fssystem_nca_file_system_driver.h"
 #include "core/file_sys/fssystem/fssystem_sparse_storage.h"
 #include "core/file_sys/fssystem/fssystem_switch_storage.h"
-#include "core/file_sys/vfs_offset.h"
+#include "core/file_sys/vfs/vfs_offset.h"
-#include "core/file_sys/vfs_vector.h"
+#include "core/file_sys/vfs/vfs_vector.h"
 
 namespace FileSys {
 

src/core/file_sys/fssystem/fssystem_nca_file_system_driver.h

@@ -5,7 +5,7 @@
 
 #include "core/file_sys/fssystem/fssystem_compression_common.h"
 #include "core/file_sys/fssystem/fssystem_nca_header.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 
 namespace FileSys {
 

src/core/file_sys/fssystem/fssystem_nca_reader.cpp

@@ -3,7 +3,7 @@
 
 #include "core/file_sys/fssystem/fssystem_aes_xts_storage.h"
 #include "core/file_sys/fssystem/fssystem_nca_file_system_driver.h"
-#include "core/file_sys/vfs_offset.h"
+#include "core/file_sys/vfs/vfs_offset.h"
 
 namespace FileSys {
 

src/core/file_sys/ips_layer.cpp

@@ -12,7 +12,7 @@
 #include "common/logging/log.h"
 #include "common/swap.h"
 #include "core/file_sys/ips_layer.h"
-#include "core/file_sys/vfs_vector.h"
+#include "core/file_sys/vfs/vfs_vector.h"
 
 namespace FileSys {
 

src/core/file_sys/ips_layer.h

@@ -8,7 +8,7 @@
 #include <vector>
 
 #include "common/common_types.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 
 namespace FileSys {
 

src/core/file_sys/kernel_executable.cpp

@@ -5,7 +5,7 @@
 
 #include "common/string_util.h"
 #include "core/file_sys/kernel_executable.h"
-#include "core/file_sys/vfs_offset.h"
+#include "core/file_sys/vfs/vfs_offset.h"
 #include "core/loader/loader.h"
 
 namespace FileSys {

src/core/file_sys/kernel_executable.h

@@ -10,7 +10,7 @@
 #include "common/common_funcs.h"
 #include "common/common_types.h"
 #include "common/swap.h"
-#include "core/file_sys/vfs_types.h"
+#include "core/file_sys/vfs/vfs_types.h"
 
 namespace Loader {
 enum class ResultStatus : u16;

src/core/file_sys/nca_metadata.cpp

@@ -6,7 +6,7 @@
 #include "common/logging/log.h"
 #include "common/swap.h"
 #include "core/file_sys/nca_metadata.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 
 namespace FileSys {
 

src/core/file_sys/nca_metadata.h

@@ -8,7 +8,7 @@
 #include "common/common_funcs.h"
 #include "common/common_types.h"
 #include "common/swap.h"
-#include "core/file_sys/vfs_types.h"
+#include "core/file_sys/vfs/vfs_types.h"
 
 namespace FileSys {
 class CNMT;

src/core/file_sys/partition_filesystem.cpp

@@ -9,7 +9,7 @@
 
 #include "common/logging/log.h"
 #include "core/file_sys/partition_filesystem.h"
-#include "core/file_sys/vfs_offset.h"
+#include "core/file_sys/vfs/vfs_offset.h"
 #include "core/loader/loader.h"
 
 namespace FileSys {

src/core/file_sys/partition_filesystem.h

@@ -9,7 +9,7 @@
 #include "common/common_funcs.h"
 #include "common/common_types.h"
 #include "common/swap.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 
 namespace Loader {
 enum class ResultStatus : u16;

src/core/file_sys/patch_manager.cpp

@@ -21,9 +21,9 @@
 #include "core/file_sys/patch_manager.h"
 #include "core/file_sys/registered_cache.h"
 #include "core/file_sys/romfs.h"
-#include "core/file_sys/vfs_cached.h"
+#include "core/file_sys/vfs/vfs_cached.h"
-#include "core/file_sys/vfs_layered.h"
+#include "core/file_sys/vfs/vfs_layered.h"
-#include "core/file_sys/vfs_vector.h"
+#include "core/file_sys/vfs/vfs_vector.h"
 #include "core/hle/service/filesystem/filesystem.h"
 #include "core/hle/service/ns/language.h"
 #include "core/hle/service/set/settings_server.h"

src/core/file_sys/patch_manager.h

@@ -9,7 +9,7 @@
 #include <string>
 #include "common/common_types.h"
 #include "core/file_sys/nca_metadata.h"
-#include "core/file_sys/vfs_types.h"
+#include "core/file_sys/vfs/vfs_types.h"
 #include "core/memory/dmnt_cheat_types.h"
 
 namespace Core {

src/core/file_sys/program_metadata.cpp

@@ -7,7 +7,7 @@
 #include "common/logging/log.h"
 #include "common/scope_exit.h"
 #include "core/file_sys/program_metadata.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 #include "core/loader/loader.h"
 
 namespace FileSys {

src/core/file_sys/program_metadata.h

@@ -10,7 +10,7 @@
 #include "common/common_funcs.h"
 #include "common/common_types.h"
 #include "common/swap.h"
-#include "core/file_sys/vfs_types.h"
+#include "core/file_sys/vfs/vfs_types.h"
 
 namespace Loader {
 enum class ResultStatus : u16;

src/core/file_sys/registered_cache.cpp

@@ -17,7 +17,7 @@
 #include "core/file_sys/nca_metadata.h"
 #include "core/file_sys/registered_cache.h"
 #include "core/file_sys/submission_package.h"
-#include "core/file_sys/vfs_concat.h"
+#include "core/file_sys/vfs/vfs_concat.h"
 #include "core/loader/loader.h"
 
 namespace FileSys {

src/core/file_sys/registered_cache.h

@@ -11,7 +11,7 @@
 #include <boost/container/flat_map.hpp>
 #include "common/common_types.h"
 #include "core/crypto/key_manager.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 
 namespace FileSys {
 class CNMT;

src/core/file_sys/romfs.cpp

@@ -9,11 +9,11 @@
 #include "common/swap.h"
 #include "core/file_sys/fsmitm_romfsbuild.h"
 #include "core/file_sys/romfs.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
-#include "core/file_sys/vfs_cached.h"
+#include "core/file_sys/vfs/vfs_cached.h"
-#include "core/file_sys/vfs_concat.h"
+#include "core/file_sys/vfs/vfs_concat.h"
-#include "core/file_sys/vfs_offset.h"
+#include "core/file_sys/vfs/vfs_offset.h"
-#include "core/file_sys/vfs_vector.h"
+#include "core/file_sys/vfs/vfs_vector.h"
 
 namespace FileSys {
 namespace {

src/core/file_sys/romfs.h

@@ -3,7 +3,7 @@
 
 #pragma once
 
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 
 namespace FileSys {
 

src/core/file_sys/romfs_factory.h

@@ -6,7 +6,7 @@
 #include <memory>
 
 #include "common/common_types.h"
-#include "core/file_sys/vfs_types.h"
+#include "core/file_sys/vfs/vfs_types.h"
 #include "core/hle/result.h"
 
 namespace Loader {

src/core/file_sys/savedata_factory.cpp

@@ -8,7 +8,7 @@
 #include "common/uuid.h"
 #include "core/core.h"
 #include "core/file_sys/savedata_factory.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 
 namespace FileSys {
 

src/core/file_sys/savedata_factory.h

@@ -7,7 +7,7 @@
 #include <string>
 #include "common/common_funcs.h"
 #include "common/common_types.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 #include "core/hle/result.h"
 
 namespace Core {

src/core/file_sys/sdmc_factory.cpp

@@ -4,7 +4,7 @@
 #include <memory>
 #include "core/file_sys/registered_cache.h"
 #include "core/file_sys/sdmc_factory.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 #include "core/file_sys/xts_archive.h"
 
 namespace FileSys {

src/core/file_sys/sdmc_factory.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #include <memory>
-#include "core/file_sys/vfs_types.h"
+#include "core/file_sys/vfs/vfs_types.h"
 #include "core/hle/result.h"
 
 namespace FileSys {

src/core/file_sys/submission_package.h

@@ -9,7 +9,7 @@
 #include <vector>
 #include "common/common_types.h"
 #include "core/file_sys/nca_metadata.h"
-#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs/vfs.h"
 
 namespace Core::Crypto {
 class KeyManager;

src/core/file_sys/system_archive/mii_model.cpp

@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #include "core/file_sys/system_archive/mii_model.h"
-#include "core/file_sys/vfs_vector.h"
+#include "core/file_sys/vfs/vfs_vector.h"
 
 namespace FileSys::SystemArchive {
 

src/core/file_sys/system_archive/mii_model.h

@@ -3,7 +3,7 @@
 
 #pragma once
 
-#include "core/file_sys/vfs_types.h"
+#include "core/file_sys/vfs/vfs_types.h"
 
 namespace FileSys::SystemArchive {
 

src/core/file_sys/system_archive/ng_word.cpp

@@ -4,7 +4,7 @@
 #include <fmt/format.h>
 #include "common/common_types.h"
 #include "core/file_sys/system_archive/ng_word.h"
-#include "core/file_sys/vfs_vector.h"
+#include "core/file_sys/vfs/vfs_vector.h"
 
 namespace FileSys::SystemArchive {
 

src/core/file_sys/system_archive/ng_word.h

@@ -3,7 +3,7 @@
 
 #pragma once
 
-#include "core/file_sys/vfs_types.h"
+#include "core/file_sys/vfs/vfs_types.h"
 
 namespace FileSys::SystemArchive {
 

src/core/file_sys/system_archive/shared_font.cpp

@@ -8,7 +8,7 @@
 #include "core/file_sys/system_archive/data/font_nintendo_extended.h"
 #include "core/file_sys/system_archive/data/font_standard.h"
 #include "core/file_sys/system_archive/shared_font.h"
-#include "core/file_sys/vfs_vector.h"
+#include "core/file_sys/vfs/vfs_vector.h"
 #include "core/hle/service/ns/iplatform_service_manager.h"
 
 namespace FileSys::SystemArchive {

src/core/file_sys/system_archive/shared_font.h

@@ -3,7 +3,7 @@
 
 #pragma once
 
-#include "core/file_sys/vfs_types.h"
+#include "core/file_sys/vfs/vfs_types.h"
 
 namespace FileSys::SystemArchive {
 

src/core/file_sys/system_archive/system_archive.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #include "common/common_types.h"
-#include "core/file_sys/vfs_types.h"
+#include "core/file_sys/vfs/vfs_types.h"
 
 namespace FileSys::SystemArchive {
 

src/core/file_sys/system_archive/system_version.cpp

@@ -3,7 +3,7 @@
 
 #include "common/logging/log.h"
 #include "core/file_sys/system_archive/system_version.h"
-#include "core/file_sys/vfs_vector.h"
+#include "core/file_sys/vfs/vfs_vector.h"
 #include "core/hle/api_version.h"
 
 namespace FileSys::SystemArchive {

src/core/file_sys/system_archive/system_version.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #include <string>
-#include "core/file_sys/vfs_types.h"
+#include "core/file_sys/vfs/vfs_types.h"
 
 namespace FileSys::SystemArchive {
 

src/core/file_sys/system_archive/time_zone_binary.cpp

@@ -5,7 +5,7 @@
 
 #include "common/swap.h"
 #include "core/file_sys/system_archive/time_zone_binary.h"
-#include "core/file_sys/vfs_vector.h"
+#include "core/file_sys/vfs/vfs_vector.h"
 
 #include "nx_tzdb.h"
 

src/core/file_sys/system_archive/time_zone_binary.h

@@ -3,7 +3,7 @@
 
 #pragma once
 
-#include "core/file_sys/vfs_types.h"
+#include "core/file_sys/vfs/vfs_types.h"
 
 namespace FileSys::SystemArchive {
 

src/core/file_sys/vfs/vfs.cpp

@@ -0,0 +1,551 @@
+// SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <algorithm>
+#include <numeric>
+#include <string>
+#include "common/fs/path_util.h"
+#include "core/file_sys/vfs/vfs.h"
+
+namespace FileSys {
+
+VfsFilesystem::VfsFilesystem(VirtualDir root_) : root(std::move(root_)) {}
+
+VfsFilesystem::~VfsFilesystem() = default;
+
+std::string VfsFilesystem::GetName() const {
+    return root->GetName();
+}
+
+bool VfsFilesystem::IsReadable() const {
+    return root->IsReadable();
+}
+
+bool VfsFilesystem::IsWritable() const {
+    return root->IsWritable();
+}
+
+VfsEntryType VfsFilesystem::GetEntryType(std::string_view path_) const {
+    const auto path = Common::FS::SanitizePath(path_);
+    if (root->GetFileRelative(path) != nullptr)
+        return VfsEntryType::File;
+    if (root->GetDirectoryRelative(path) != nullptr)
+        return VfsEntryType::Directory;
+
+    return VfsEntryType::None;
+}
+
+VirtualFile VfsFilesystem::OpenFile(std::string_view path_, OpenMode perms) {
+    const auto path = Common::FS::SanitizePath(path_);
+    return root->GetFileRelative(path);
+}
+
+VirtualFile VfsFilesystem::CreateFile(std::string_view path_, OpenMode perms) {
+    const auto path = Common::FS::SanitizePath(path_);
+    return root->CreateFileRelative(path);
+}
+
+VirtualFile VfsFilesystem::CopyFile(std::string_view old_path_, std::string_view new_path_) {
+    const auto old_path = Common::FS::SanitizePath(old_path_);
+    const auto new_path = Common::FS::SanitizePath(new_path_);
+
+    // VfsDirectory impls are only required to implement copy across the current directory.
+    if (Common::FS::GetParentPath(old_path) == Common::FS::GetParentPath(new_path)) {
+        if (!root->Copy(Common::FS::GetFilename(old_path), Common::FS::GetFilename(new_path)))
+            return nullptr;
+        return OpenFile(new_path, OpenMode::ReadWrite);
+    }
+
+    // Do it using RawCopy. Non-default impls are encouraged to optimize this.
+    const auto old_file = OpenFile(old_path, OpenMode::Read);
+    if (old_file == nullptr)
+        return nullptr;
+    auto new_file = OpenFile(new_path, OpenMode::Read);
+    if (new_file != nullptr)
+        return nullptr;
+    new_file = CreateFile(new_path, OpenMode::Write);
+    if (new_file == nullptr)
+        return nullptr;
+    if (!VfsRawCopy(old_file, new_file))
+        return nullptr;
+    return new_file;
+}
+
+VirtualFile VfsFilesystem::MoveFile(std::string_view old_path, std::string_view new_path) {
+    const auto sanitized_old_path = Common::FS::SanitizePath(old_path);
+    const auto sanitized_new_path = Common::FS::SanitizePath(new_path);
+
+    // Again, non-default impls are highly encouraged to provide a more optimized version of this.
+    auto out = CopyFile(sanitized_old_path, sanitized_new_path);
+    if (out == nullptr)
+        return nullptr;
+    if (DeleteFile(sanitized_old_path))
+        return out;
+    return nullptr;
+}
+
+bool VfsFilesystem::DeleteFile(std::string_view path_) {
+    const auto path = Common::FS::SanitizePath(path_);
+    auto parent = OpenDirectory(Common::FS::GetParentPath(path), OpenMode::Write);
+    if (parent == nullptr)
+        return false;
+    return parent->DeleteFile(Common::FS::GetFilename(path));
+}
+
+VirtualDir VfsFilesystem::OpenDirectory(std::string_view path_, OpenMode perms) {
+    const auto path = Common::FS::SanitizePath(path_);
+    return root->GetDirectoryRelative(path);
+}
+
+VirtualDir VfsFilesystem::CreateDirectory(std::string_view path_, OpenMode perms) {
+    const auto path = Common::FS::SanitizePath(path_);
+    return root->CreateDirectoryRelative(path);
+}
+
+VirtualDir VfsFilesystem::CopyDirectory(std::string_view old_path_, std::string_view new_path_) {
+    const auto old_path = Common::FS::SanitizePath(old_path_);
+    const auto new_path = Common::FS::SanitizePath(new_path_);
+
+    // Non-default impls are highly encouraged to provide a more optimized version of this.
+    auto old_dir = OpenDirectory(old_path, OpenMode::Read);
+    if (old_dir == nullptr)
+        return nullptr;
+    auto new_dir = OpenDirectory(new_path, OpenMode::Read);
+    if (new_dir != nullptr)
+        return nullptr;
+    new_dir = CreateDirectory(new_path, OpenMode::Write);
+    if (new_dir == nullptr)
+        return nullptr;
+
+    for (const auto& file : old_dir->GetFiles()) {
+        const auto x = CopyFile(old_path + '/' + file->GetName(), new_path + '/' + file->GetName());
+        if (x == nullptr)
+            return nullptr;
+    }
+
+    for (const auto& dir : old_dir->GetSubdirectories()) {
+        const auto x =
+            CopyDirectory(old_path + '/' + dir->GetName(), new_path + '/' + dir->GetName());
+        if (x == nullptr)
+            return nullptr;
+    }
+
+    return new_dir;
+}
+
+VirtualDir VfsFilesystem::MoveDirectory(std::string_view old_path, std::string_view new_path) {
+    const auto sanitized_old_path = Common::FS::SanitizePath(old_path);
+    const auto sanitized_new_path = Common::FS::SanitizePath(new_path);
+
+    // Non-default impls are highly encouraged to provide a more optimized version of this.
+    auto out = CopyDirectory(sanitized_old_path, sanitized_new_path);
+    if (out == nullptr)
+        return nullptr;
+    if (DeleteDirectory(sanitized_old_path))
+        return out;
+    return nullptr;
+}
+
+bool VfsFilesystem::DeleteDirectory(std::string_view path_) {
+    const auto path = Common::FS::SanitizePath(path_);
+    auto parent = OpenDirectory(Common::FS::GetParentPath(path), OpenMode::Write);
+    if (parent == nullptr)
+        return false;
+    return parent->DeleteSubdirectoryRecursive(Common::FS::GetFilename(path));
+}
+
+VfsFile::~VfsFile() = default;
+
+std::string VfsFile::GetExtension() const {
+    return std::string(Common::FS::GetExtensionFromFilename(GetName()));
+}
+
+VfsDirectory::~VfsDirectory() = default;
+
+std::optional<u8> VfsFile::ReadByte(std::size_t offset) const {
+    u8 out{};
+    const std::size_t size = Read(&out, sizeof(u8), offset);
+    if (size == 1) {
+        return out;
+    }
+
+    return std::nullopt;
+}
+
+std::vector<u8> VfsFile::ReadBytes(std::size_t size, std::size_t offset) const {
+    std::vector<u8> out(size);
+    std::size_t read_size = Read(out.data(), size, offset);
+    out.resize(read_size);
+    return out;
+}
+
+std::vector<u8> VfsFile::ReadAllBytes() const {
+    return ReadBytes(GetSize());
+}
+
+bool VfsFile::WriteByte(u8 data, std::size_t offset) {
+    return Write(&data, 1, offset) == 1;
+}
+
+std::size_t VfsFile::WriteBytes(const std::vector<u8>& data, std::size_t offset) {
+    return Write(data.data(), data.size(), offset);
+}
+
+std::string VfsFile::GetFullPath() const {
+    if (GetContainingDirectory() == nullptr)
+        return '/' + GetName();
+
+    return GetContainingDirectory()->GetFullPath() + '/' + GetName();
+}
+
+VirtualFile VfsDirectory::GetFileRelative(std::string_view path) const {
+    auto vec = Common::FS::SplitPathComponents(path);
+    if (vec.empty()) {
+        return nullptr;
+    }
+
+    if (vec.size() == 1) {
+        return GetFile(vec[0]);
+    }
+
+    auto dir = GetSubdirectory(vec[0]);
+    for (std::size_t component = 1; component < vec.size() - 1; ++component) {
+        if (dir == nullptr) {
+            return nullptr;
+        }
+
+        dir = dir->GetSubdirectory(vec[component]);
+    }
+
+    if (dir == nullptr) {
+        return nullptr;
+    }
+
+    return dir->GetFile(vec.back());
+}
+
+VirtualFile VfsDirectory::GetFileAbsolute(std::string_view path) const {
+    if (IsRoot()) {
+        return GetFileRelative(path);
+    }
+
+    return GetParentDirectory()->GetFileAbsolute(path);
+}
+
+VirtualDir VfsDirectory::GetDirectoryRelative(std::string_view path) const {
+    auto vec = Common::FS::SplitPathComponents(path);
+    if (vec.empty()) {
+        // TODO(DarkLordZach): Return this directory if path is '/' or similar. Can't currently
+        // because of const-ness
+        return nullptr;
+    }
+
+    auto dir = GetSubdirectory(vec[0]);
+    for (std::size_t component = 1; component < vec.size(); ++component) {
+        if (dir == nullptr) {
+            return nullptr;
+        }
+
+        dir = dir->GetSubdirectory(vec[component]);
+    }
+
+    return dir;
+}
+
+VirtualDir VfsDirectory::GetDirectoryAbsolute(std::string_view path) const {
+    if (IsRoot()) {
+        return GetDirectoryRelative(path);
+    }
+
+    return GetParentDirectory()->GetDirectoryAbsolute(path);
+}
+
+VirtualFile VfsDirectory::GetFile(std::string_view name) const {
+    const auto& files = GetFiles();
+    const auto iter = std::find_if(files.begin(), files.end(),
+                                   [&name](const auto& file1) { return name == file1->GetName(); });
+    return iter == files.end() ? nullptr : *iter;
+}
+
+FileTimeStampRaw VfsDirectory::GetFileTimeStamp([[maybe_unused]] std::string_view path) const {
+    return {};
+}
+
+VirtualDir VfsDirectory::GetSubdirectory(std::string_view name) const {
+    const auto& subs = GetSubdirectories();
+    const auto iter = std::find_if(subs.begin(), subs.end(),
+                                   [&name](const auto& file1) { return name == file1->GetName(); });
+    return iter == subs.end() ? nullptr : *iter;
+}
+
+bool VfsDirectory::IsRoot() const {
+    return GetParentDirectory() == nullptr;
+}
+
+std::size_t VfsDirectory::GetSize() const {
+    const auto& files = GetFiles();
+    const auto sum_sizes = [](const auto& range) {
+        return std::accumulate(range.begin(), range.end(), 0ULL,
+                               [](const auto& f1, const auto& f2) { return f1 + f2->GetSize(); });
+    };
+
+    const auto file_total = sum_sizes(files);
+    const auto& sub_dir = GetSubdirectories();
+    const auto subdir_total = sum_sizes(sub_dir);
+
+    return file_total + subdir_total;
+}
+
+VirtualFile VfsDirectory::CreateFileRelative(std::string_view path) {
+    auto vec = Common::FS::SplitPathComponents(path);
+    if (vec.empty()) {
+        return nullptr;
+    }
+
+    if (vec.size() == 1) {
+        return CreateFile(vec[0]);
+    }
+
+    auto dir = GetSubdirectory(vec[0]);
+    if (dir == nullptr) {
+        dir = CreateSubdirectory(vec[0]);
+        if (dir == nullptr) {
+            return nullptr;
+        }
+    }
+
+    return dir->CreateFileRelative(Common::FS::GetPathWithoutTop(path));
+}
+
+VirtualFile VfsDirectory::CreateFileAbsolute(std::string_view path) {
+    if (IsRoot()) {
+        return CreateFileRelative(path);
+    }
+
+    return GetParentDirectory()->CreateFileAbsolute(path);
+}
+
+VirtualDir VfsDirectory::CreateDirectoryRelative(std::string_view path) {
+    auto vec = Common::FS::SplitPathComponents(path);
+    if (vec.empty()) {
+        return nullptr;
+    }
+
+    if (vec.size() == 1) {
+        return CreateSubdirectory(vec[0]);
+    }
+
+    auto dir = GetSubdirectory(vec[0]);
+    if (dir == nullptr) {
+        dir = CreateSubdirectory(vec[0]);
+        if (dir == nullptr) {
+            return nullptr;
+        }
+    }
+
+    return dir->CreateDirectoryRelative(Common::FS::GetPathWithoutTop(path));
+}
+
+VirtualDir VfsDirectory::CreateDirectoryAbsolute(std::string_view path) {
+    if (IsRoot()) {
+        return CreateDirectoryRelative(path);
+    }
+
+    return GetParentDirectory()->CreateDirectoryAbsolute(path);
+}
+
+bool VfsDirectory::DeleteSubdirectoryRecursive(std::string_view name) {
+    auto dir = GetSubdirectory(name);
+    if (dir == nullptr) {
+        return false;
+    }
+
+    bool success = true;
+    for (const auto& file : dir->GetFiles()) {
+        if (!DeleteFile(file->GetName())) {
+            success = false;
+        }
+    }
+
+    for (const auto& sdir : dir->GetSubdirectories()) {
+        if (!dir->DeleteSubdirectoryRecursive(sdir->GetName())) {
+            success = false;
+        }
+    }
+
+    return success;
+}
+
+bool VfsDirectory::CleanSubdirectoryRecursive(std::string_view name) {
+    auto dir = GetSubdirectory(name);
+    if (dir == nullptr) {
+        return false;
+    }
+
+    bool success = true;
+    for (const auto& file : dir->GetFiles()) {
+        if (!dir->DeleteFile(file->GetName())) {
+            success = false;
+        }
+    }
+
+    for (const auto& sdir : dir->GetSubdirectories()) {
+        if (!dir->DeleteSubdirectoryRecursive(sdir->GetName())) {
+            success = false;
+        }
+    }
+
+    return success;
+}
+
+bool VfsDirectory::Copy(std::string_view src, std::string_view dest) {
+    const auto f1 = GetFile(src);
+    auto f2 = CreateFile(dest);
+    if (f1 == nullptr || f2 == nullptr) {
+        return false;
+    }
+
+    if (!f2->Resize(f1->GetSize())) {
+        DeleteFile(dest);
+        return false;
+    }
+
+    return f2->WriteBytes(f1->ReadAllBytes()) == f1->GetSize();
+}
+
+std::map<std::string, VfsEntryType, std::less<>> VfsDirectory::GetEntries() const {
+    std::map<std::string, VfsEntryType, std::less<>> out;
+    for (const auto& dir : GetSubdirectories())
+        out.emplace(dir->GetName(), VfsEntryType::Directory);
+    for (const auto& file : GetFiles())
+        out.emplace(file->GetName(), VfsEntryType::File);
+    return out;
+}
+
+std::string VfsDirectory::GetFullPath() const {
+    if (IsRoot())
+        return GetName();
+
+    return GetParentDirectory()->GetFullPath() + '/' + GetName();
+}
+
+bool ReadOnlyVfsDirectory::IsWritable() const {
+    return false;
+}
+
+bool ReadOnlyVfsDirectory::IsReadable() const {
+    return true;
+}
+
+VirtualDir ReadOnlyVfsDirectory::CreateSubdirectory(std::string_view name) {
+    return nullptr;
+}
+
+VirtualFile ReadOnlyVfsDirectory::CreateFile(std::string_view name) {
+    return nullptr;
+}
+
+VirtualFile ReadOnlyVfsDirectory::CreateFileAbsolute(std::string_view path) {
+    return nullptr;
+}
+
+VirtualFile ReadOnlyVfsDirectory::CreateFileRelative(std::string_view path) {
+    return nullptr;
+}
+
+VirtualDir ReadOnlyVfsDirectory::CreateDirectoryAbsolute(std::string_view path) {
+    return nullptr;
+}
+
+VirtualDir ReadOnlyVfsDirectory::CreateDirectoryRelative(std::string_view path) {
+    return nullptr;
+}
+
+bool ReadOnlyVfsDirectory::DeleteSubdirectory(std::string_view name) {
+    return false;
+}
+
+bool ReadOnlyVfsDirectory::DeleteSubdirectoryRecursive(std::string_view name) {
+    return false;
+}
+
+bool ReadOnlyVfsDirectory::CleanSubdirectoryRecursive(std::string_view name) {
+    return false;
+}
+
+bool ReadOnlyVfsDirectory::DeleteFile(std::string_view name) {
+    return false;
+}
+
+bool ReadOnlyVfsDirectory::Rename(std::string_view name) {
+    return false;
+}
+
+bool DeepEquals(const VirtualFile& file1, const VirtualFile& file2, std::size_t block_size) {
+    if (file1->GetSize() != file2->GetSize())
+        return false;
+
+    std::vector<u8> f1_v(block_size);
+    std::vector<u8> f2_v(block_size);
+    for (std::size_t i = 0; i < file1->GetSize(); i += block_size) {
+        auto f1_vs = file1->Read(f1_v.data(), block_size, i);
+        auto f2_vs = file2->Read(f2_v.data(), block_size, i);
+
+        if (f1_vs != f2_vs)
+            return false;
+        auto iters = std::mismatch(f1_v.begin(), f1_v.end(), f2_v.begin(), f2_v.end());
+        if (iters.first != f1_v.end() && iters.second != f2_v.end())
+            return false;
+    }
+
+    return true;
+}
+
+bool VfsRawCopy(const VirtualFile& src, const VirtualFile& dest, std::size_t block_size) {
+    if (src == nullptr || dest == nullptr || !src->IsReadable() || !dest->IsWritable())
+        return false;
+    if (!dest->Resize(src->GetSize()))
+        return false;
+
+    std::vector<u8> temp(std::min(block_size, src->GetSize()));
+    for (std::size_t i = 0; i < src->GetSize(); i += block_size) {
+        const auto read = std::min(block_size, src->GetSize() - i);
+
+        if (src->Read(temp.data(), read, i) != read) {
+            return false;
+        }
+
+        if (dest->Write(temp.data(), read, i) != read) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+bool VfsRawCopyD(const VirtualDir& src, const VirtualDir& dest, std::size_t block_size) {
+    if (src == nullptr || dest == nullptr || !src->IsReadable() || !dest->IsWritable())
+        return false;
+
+    for (const auto& file : src->GetFiles()) {
+        const auto out = dest->CreateFile(file->GetName());
+        if (!VfsRawCopy(file, out, block_size))
+            return false;
+    }
+
+    for (const auto& dir : src->GetSubdirectories()) {
+        const auto out = dest->CreateSubdirectory(dir->GetName());
+        if (!VfsRawCopyD(dir, out, block_size))
+            return false;
+    }
+
+    return true;
+}
+
+VirtualDir GetOrCreateDirectoryRelative(const VirtualDir& rel, std::string_view path) {
+    const auto res = rel->GetDirectoryRelative(path);
+    if (res == nullptr)
+        return rel->CreateDirectoryRelative(path);
+    return res;
+}
+} // namespace FileSys

src/core/file_sys/vfs/vfs.h

@@ -0,0 +1,326 @@
+// SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <functional>
+#include <map>
+#include <memory>
+#include <optional>
+#include <string>
+#include <type_traits>
+#include <vector>
+
+#include "common/common_funcs.h"
+#include "common/common_types.h"
+#include "core/file_sys/fs_filesystem.h"
+#include "core/file_sys/vfs/vfs_types.h"
+
+namespace FileSys {
+
+// An enumeration representing what can be at the end of a path in a VfsFilesystem
+enum class VfsEntryType {
+    None,
+    File,
+    Directory,
+};
+
+// A class representing an abstract filesystem. A default implementation given the root VirtualDir
+// is provided for convenience, but if the Vfs implementation has any additional state or
+// functionality, they will need to override.
+class VfsFilesystem {
+public:
+    YUZU_NON_COPYABLE(VfsFilesystem);
+    YUZU_NON_MOVEABLE(VfsFilesystem);
+
+    explicit VfsFilesystem(VirtualDir root);
+    virtual ~VfsFilesystem();
+
+    // Gets the friendly name for the filesystem.
+    virtual std::string GetName() const;
+
+    // Return whether or not the user has read permissions on this filesystem.
+    virtual bool IsReadable() const;
+    // Return whether or not the user has write permission on this filesystem.
+    virtual bool IsWritable() const;
+
+    // Determine if the entry at path is non-existent, a file, or a directory.
+    virtual VfsEntryType GetEntryType(std::string_view path) const;
+
+    // Opens the file with path relative to root. If it doesn't exist, returns nullptr.
+    virtual VirtualFile OpenFile(std::string_view path, OpenMode perms);
+    // Creates a new, empty file at path
+    virtual VirtualFile CreateFile(std::string_view path, OpenMode perms);
+    // Copies the file from old_path to new_path, returning the new file on success and nullptr on
+    // failure.
+    virtual VirtualFile CopyFile(std::string_view old_path, std::string_view new_path);
+    // Moves the file from old_path to new_path, returning the moved file on success and nullptr on
+    // failure.
+    virtual VirtualFile MoveFile(std::string_view old_path, std::string_view new_path);
+    // Deletes the file with path relative to root, returning true on success.
+    virtual bool DeleteFile(std::string_view path);
+
+    // Opens the directory with path relative to root. If it doesn't exist, returns nullptr.
+    virtual VirtualDir OpenDirectory(std::string_view path, OpenMode perms);
+    // Creates a new, empty directory at path
+    virtual VirtualDir CreateDirectory(std::string_view path, OpenMode perms);
+    // Copies the directory from old_path to new_path, returning the new directory on success and
+    // nullptr on failure.
+    virtual VirtualDir CopyDirectory(std::string_view old_path, std::string_view new_path);
+    // Moves the directory from old_path to new_path, returning the moved directory on success and
+    // nullptr on failure.
+    virtual VirtualDir MoveDirectory(std::string_view old_path, std::string_view new_path);
+    // Deletes the directory with path relative to root, returning true on success.
+    virtual bool DeleteDirectory(std::string_view path);
+
+protected:
+    // Root directory in default implementation.
+    VirtualDir root;
+};
+
+// A class representing a file in an abstract filesystem.
+class VfsFile {
+public:
+    YUZU_NON_COPYABLE(VfsFile);
+    YUZU_NON_MOVEABLE(VfsFile);
+
+    VfsFile() = default;
+    virtual ~VfsFile();
+
+    // Retrieves the file name.
+    virtual std::string GetName() const = 0;
+    // Retrieves the extension of the file name.
+    virtual std::string GetExtension() const;
+    // Retrieves the size of the file.
+    virtual std::size_t GetSize() const = 0;
+    // Resizes the file to new_size. Returns whether or not the operation was successful.
+    virtual bool Resize(std::size_t new_size) = 0;
+    // Gets a pointer to the directory containing this file, returning nullptr if there is none.
+    virtual VirtualDir GetContainingDirectory() const = 0;
+
+    // Returns whether or not the file can be written to.
+    virtual bool IsWritable() const = 0;
+    // Returns whether or not the file can be read from.
+    virtual bool IsReadable() const = 0;
+
+    // The primary method of reading from the file. Reads length bytes into data starting at offset
+    // into file. Returns number of bytes successfully read.
+    virtual std::size_t Read(u8* data, std::size_t length, std::size_t offset = 0) const = 0;
+    // The primary method of writing to the file. Writes length bytes from data starting at offset
+    // into file. Returns number of bytes successfully written.
+    virtual std::size_t Write(const u8* data, std::size_t length, std::size_t offset = 0) = 0;
+
+    // Reads exactly one byte at the offset provided, returning std::nullopt on error.
+    virtual std::optional<u8> ReadByte(std::size_t offset = 0) const;
+    // Reads size bytes starting at offset in file into a vector.
+    virtual std::vector<u8> ReadBytes(std::size_t size, std::size_t offset = 0) const;
+    // Reads all the bytes from the file into a vector. Equivalent to 'file->Read(file->GetSize(),
+    // 0)'
+    virtual std::vector<u8> ReadAllBytes() const;
+
+    // Reads an array of type T, size number_elements starting at offset.
+    // Returns the number of bytes (sizeof(T)*number_elements) read successfully.
+    template <typename T>
+    std::size_t ReadArray(T* data, std::size_t number_elements, std::size_t offset = 0) const {
+        static_assert(std::is_trivially_copyable_v<T>, "Data type must be trivially copyable.");
+
+        return Read(reinterpret_cast<u8*>(data), number_elements * sizeof(T), offset);
+    }
+
+    // Reads size bytes into the memory starting at data starting at offset into the file.
+    // Returns the number of bytes read successfully.
+    template <typename T>
+    std::size_t ReadBytes(T* data, std::size_t size, std::size_t offset = 0) const {
+        static_assert(std::is_trivially_copyable_v<T>, "Data type must be trivially copyable.");
+        return Read(reinterpret_cast<u8*>(data), size, offset);
+    }
+
+    // Reads one object of type T starting at offset in file.
+    // Returns the number of bytes read successfully (sizeof(T)).
+    template <typename T>
+    std::size_t ReadObject(T* data, std::size_t offset = 0) const {
+        static_assert(std::is_trivially_copyable_v<T>, "Data type must be trivially copyable.");
+        return Read(reinterpret_cast<u8*>(data), sizeof(T), offset);
+    }
+
+    // Writes exactly one byte to offset in file and returns whether or not the byte was written
+    // successfully.
+    virtual bool WriteByte(u8 data, std::size_t offset = 0);
+    // Writes a vector of bytes to offset in file and returns the number of bytes successfully
+    // written.
+    virtual std::size_t WriteBytes(const std::vector<u8>& data, std::size_t offset = 0);
+
+    // Writes an array of type T, size number_elements to offset in file.
+    // Returns the number of bytes (sizeof(T)*number_elements) written successfully.
+    template <typename T>
+    std::size_t WriteArray(const T* data, std::size_t number_elements, std::size_t offset = 0) {
+        static_assert(std::is_trivially_copyable_v<T>, "Data type must be trivially copyable.");
+        return Write(reinterpret_cast<const u8*>(data), number_elements * sizeof(T), offset);
+    }
+
+    // Writes size bytes starting at memory location data to offset in file.
+    // Returns the number of bytes written successfully.
+    template <typename T>
+    std::size_t WriteBytes(const T* data, std::size_t size, std::size_t offset = 0) {
+        static_assert(std::is_trivially_copyable_v<T>, "Data type must be trivially copyable.");
+        return Write(reinterpret_cast<const u8*>(data), size, offset);
+    }
+
+    // Writes one object of type T to offset in file.
+    // Returns the number of bytes written successfully (sizeof(T)).
+    template <typename T>
+    std::size_t WriteObject(const T& data, std::size_t offset = 0) {
+        static_assert(std::is_trivially_copyable_v<T>, "Data type must be trivially copyable.");
+        return Write(reinterpret_cast<const u8*>(&data), sizeof(T), offset);
+    }
+
+    // Renames the file to name. Returns whether or not the operation was successful.
+    virtual bool Rename(std::string_view name) = 0;
+
+    // Returns the full path of this file as a string, recursively
+    virtual std::string GetFullPath() const;
+};
+
+// A class representing a directory in an abstract filesystem.
+class VfsDirectory {
+public:
+    YUZU_NON_COPYABLE(VfsDirectory);
+    YUZU_NON_MOVEABLE(VfsDirectory);
+
+    VfsDirectory() = default;
+    virtual ~VfsDirectory();
+
+    // Retrieves the file located at path as if the current directory was root. Returns nullptr if
+    // not found.
+    virtual VirtualFile GetFileRelative(std::string_view path) const;
+    // Calls GetFileRelative(path) on the root of the current directory.
+    virtual VirtualFile GetFileAbsolute(std::string_view path) const;
+
+    // Retrieves the directory located at path as if the current directory was root. Returns nullptr
+    // if not found.
+    virtual VirtualDir GetDirectoryRelative(std::string_view path) const;
+    // Calls GetDirectoryRelative(path) on the root of the current directory.
+    virtual VirtualDir GetDirectoryAbsolute(std::string_view path) const;
+
+    // Returns a vector containing all of the files in this directory.
+    virtual std::vector<VirtualFile> GetFiles() const = 0;
+    // Returns the file with filename matching name. Returns nullptr if directory doesn't have a
+    // file with name.
+    virtual VirtualFile GetFile(std::string_view name) const;
+
+    // Returns a struct containing the file's timestamp.
+    virtual FileTimeStampRaw GetFileTimeStamp(std::string_view path) const;
+
+    // Returns a vector containing all of the subdirectories in this directory.
+    virtual std::vector<VirtualDir> GetSubdirectories() const = 0;
+    // Returns the directory with name matching name. Returns nullptr if directory doesn't have a
+    // directory with name.
+    virtual VirtualDir GetSubdirectory(std::string_view name) const;
+
+    // Returns whether or not the directory can be written to.
+    virtual bool IsWritable() const = 0;
+    // Returns whether of not the directory can be read from.
+    virtual bool IsReadable() const = 0;
+
+    // Returns whether or not the directory is the root of the current file tree.
+    virtual bool IsRoot() const;
+
+    // Returns the name of the directory.
+    virtual std::string GetName() const = 0;
+    // Returns the total size of all files and subdirectories in this directory.
+    virtual std::size_t GetSize() const;
+    // Returns the parent directory of this directory. Returns nullptr if this directory is root or
+    // has no parent.
+    virtual VirtualDir GetParentDirectory() const = 0;
+
+    // Creates a new subdirectory with name name. Returns a pointer to the new directory or nullptr
+    // if the operation failed.
+    virtual VirtualDir CreateSubdirectory(std::string_view name) = 0;
+    // Creates a new file with name name. Returns a pointer to the new file or nullptr if the
+    // operation failed.
+    virtual VirtualFile CreateFile(std::string_view name) = 0;
+
+    // Creates a new file at the path relative to this directory. Also creates directories if
+    // they do not exist and is supported by this implementation. Returns nullptr on any failure.
+    virtual VirtualFile CreateFileRelative(std::string_view path);
+
+    // Creates a new file at the path relative to root of this directory. Also creates directories
+    // if they do not exist and is supported by this implementation. Returns nullptr on any failure.
+    virtual VirtualFile CreateFileAbsolute(std::string_view path);
+
+    // Creates a new directory at the path relative to this directory. Also creates directories if
+    // they do not exist and is supported by this implementation. Returns nullptr on any failure.
+    virtual VirtualDir CreateDirectoryRelative(std::string_view path);
+
+    // Creates a new directory at the path relative to root of this directory. Also creates
+    // directories if they do not exist and is supported by this implementation. Returns nullptr on
+    // any failure.
+    virtual VirtualDir CreateDirectoryAbsolute(std::string_view path);
+
+    // Deletes the subdirectory with the given name and returns true on success.
+    virtual bool DeleteSubdirectory(std::string_view name) = 0;
+
+    // Deletes all subdirectories and files within the provided directory and then deletes
+    // the directory itself. Returns true on success.
+    virtual bool DeleteSubdirectoryRecursive(std::string_view name);
+
+    // Deletes all subdirectories and files within the provided directory.
+    // Unlike DeleteSubdirectoryRecursive, this does not delete the provided directory.
+    virtual bool CleanSubdirectoryRecursive(std::string_view name);
+
+    // Returns whether or not the file with name name was deleted successfully.
+    virtual bool DeleteFile(std::string_view name) = 0;
+
+    // Returns whether or not this directory was renamed to name.
+    virtual bool Rename(std::string_view name) = 0;
+
+    // Returns whether or not the file with name src was successfully copied to a new file with name
+    // dest.
+    virtual bool Copy(std::string_view src, std::string_view dest);
+
+    // Gets all of the entries directly in the directory (files and dirs), returning a map between
+    // item name -> type.
+    virtual std::map<std::string, VfsEntryType, std::less<>> GetEntries() const;
+
+    // Returns the full path of this directory as a string, recursively
+    virtual std::string GetFullPath() const;
+};
+
+// A convenience partial-implementation of VfsDirectory that stubs out methods that should only work
+// if writable. This is to avoid redundant empty methods everywhere.
+class ReadOnlyVfsDirectory : public VfsDirectory {
+public:
+    bool IsWritable() const override;
+    bool IsReadable() const override;
+    VirtualDir CreateSubdirectory(std::string_view name) override;
+    VirtualFile CreateFile(std::string_view name) override;
+    VirtualFile CreateFileAbsolute(std::string_view path) override;
+    VirtualFile CreateFileRelative(std::string_view path) override;
+    VirtualDir CreateDirectoryAbsolute(std::string_view path) override;
+    VirtualDir CreateDirectoryRelative(std::string_view path) override;
+    bool DeleteSubdirectory(std::string_view name) override;
+    bool DeleteSubdirectoryRecursive(std::string_view name) override;
+    bool CleanSubdirectoryRecursive(std::string_view name) override;
+    bool DeleteFile(std::string_view name) override;
+    bool Rename(std::string_view name) override;
+};
+
+// Compare the two files, byte-for-byte, in increments specified by block_size
+bool DeepEquals(const VirtualFile& file1, const VirtualFile& file2,
+                std::size_t block_size = 0x1000);
+
+// A method that copies the raw data between two different implementations of VirtualFile. If you
+// are using the same implementation, it is probably better to use the Copy method in the parent
+// directory of src/dest.
+bool VfsRawCopy(const VirtualFile& src, const VirtualFile& dest, std::size_t block_size = 0x1000);
+
+// A method that performs a similar function to VfsRawCopy above, but instead copies entire
+// directories. It suffers the same performance penalties as above and an implementation-specific
+// Copy should always be preferred.
+bool VfsRawCopyD(const VirtualDir& src, const VirtualDir& dest, std::size_t block_size = 0x1000);
+
+// Checks if the directory at path relative to rel exists. If it does, returns that. If it does not
+// it attempts to create it and returns the new dir or nullptr on failure.
+VirtualDir GetOrCreateDirectoryRelative(const VirtualDir& rel, std::string_view path);
+
+} // namespace FileSys

src/core/file_sys/vfs/vfs_cached.cpp

@@ -0,0 +1,63 @@
+// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "core/file_sys/vfs/vfs_cached.h"
+#include "core/file_sys/vfs/vfs_types.h"
+
+namespace FileSys {
+
+CachedVfsDirectory::CachedVfsDirectory(VirtualDir&& source_dir)
+    : name(source_dir->GetName()), parent(source_dir->GetParentDirectory()) {
+    for (auto& dir : source_dir->GetSubdirectories()) {
+        dirs.emplace(dir->GetName(), std::make_shared<CachedVfsDirectory>(std::move(dir)));
+    }
+    for (auto& file : source_dir->GetFiles()) {
+        files.emplace(file->GetName(), std::move(file));
+    }
+}
+
+CachedVfsDirectory::~CachedVfsDirectory() = default;
+
+VirtualFile CachedVfsDirectory::GetFile(std::string_view file_name) const {
+    auto it = files.find(file_name);
+    if (it != files.end()) {
+        return it->second;
+    }
+
+    return nullptr;
+}
+
+VirtualDir CachedVfsDirectory::GetSubdirectory(std::string_view dir_name) const {
+    auto it = dirs.find(dir_name);
+    if (it != dirs.end()) {
+        return it->second;
+    }
+
+    return nullptr;
+}
+
+std::vector<VirtualFile> CachedVfsDirectory::GetFiles() const {
+    std::vector<VirtualFile> out;
+    for (auto& [file_name, file] : files) {
+        out.push_back(file);
+    }
+    return out;
+}
+
+std::vector<VirtualDir> CachedVfsDirectory::GetSubdirectories() const {
+    std::vector<VirtualDir> out;
+    for (auto& [dir_name, dir] : dirs) {
+        out.push_back(dir);
+    }
+    return out;
+}
+
+std::string CachedVfsDirectory::GetName() const {
+    return name;
+}
+
+VirtualDir CachedVfsDirectory::GetParentDirectory() const {
+    return parent;
+}
+
+} // namespace FileSys

src/core/file_sys/vfs/vfs_cached.h

@@ -0,0 +1,31 @@
+// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <string_view>
+#include <vector>
+#include "core/file_sys/vfs/vfs.h"
+
+namespace FileSys {
+
+class CachedVfsDirectory : public ReadOnlyVfsDirectory {
+public:
+    CachedVfsDirectory(VirtualDir&& source_directory);
+
+    ~CachedVfsDirectory() override;
+    VirtualFile GetFile(std::string_view file_name) const override;
+    VirtualDir GetSubdirectory(std::string_view dir_name) const override;
+    std::vector<VirtualFile> GetFiles() const override;
+    std::vector<VirtualDir> GetSubdirectories() const override;
+    std::string GetName() const override;
+    VirtualDir GetParentDirectory() const override;
+
+private:
+    std::string name;
+    VirtualDir parent;
+    std::map<std::string, VirtualDir, std::less<>> dirs;
+    std::map<std::string, VirtualFile, std::less<>> files;
+};
+
+} // namespace FileSys

src/core/file_sys/vfs/vfs_concat.cpp

@@ -0,0 +1,192 @@
+// SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <algorithm>
+#include <utility>
+
+#include "common/assert.h"
+#include "core/file_sys/vfs/vfs_concat.h"
+#include "core/file_sys/vfs/vfs_static.h"
+
+namespace FileSys {
+
+ConcatenatedVfsFile::ConcatenatedVfsFile(std::string&& name_, ConcatenationMap&& concatenation_map_)
+    : concatenation_map(std::move(concatenation_map_)), name(std::move(name_)) {
+    DEBUG_ASSERT(this->VerifyContinuity());
+}
+
+bool ConcatenatedVfsFile::VerifyContinuity() const {
+    u64 last_offset = 0;
+    for (auto& entry : concatenation_map) {
+        if (entry.offset != last_offset) {
+            return false;
+        }
+
+        last_offset = entry.offset + entry.file->GetSize();
+    }
+
+    return true;
+}
+
+ConcatenatedVfsFile::~ConcatenatedVfsFile() = default;
+
+VirtualFile ConcatenatedVfsFile::MakeConcatenatedFile(std::string&& name,
+                                                      std::vector<VirtualFile>&& files) {
+    // Fold trivial cases.
+    if (files.empty()) {
+        return nullptr;
+    }
+    if (files.size() == 1) {
+        return files.front();
+    }
+
+    // Make the concatenation map from the input.
+    std::vector<ConcatenationEntry> concatenation_map;
+    concatenation_map.reserve(files.size());
+    u64 last_offset = 0;
+
+    for (auto& file : files) {
+        const auto size = file->GetSize();
+
+        concatenation_map.emplace_back(ConcatenationEntry{
+            .offset = last_offset,
+            .file = std::move(file),
+        });
+
+        last_offset += size;
+    }
+
+    return VirtualFile(new ConcatenatedVfsFile(std::move(name), std::move(concatenation_map)));
+}
+
+VirtualFile ConcatenatedVfsFile::MakeConcatenatedFile(
+    u8 filler_byte, std::string&& name, std::vector<std::pair<u64, VirtualFile>>&& files) {
+    // Fold trivial cases.
+    if (files.empty()) {
+        return nullptr;
+    }
+    if (files.size() == 1) {
+        return files.begin()->second;
+    }
+
+    // Make the concatenation map from the input.
+    std::vector<ConcatenationEntry> concatenation_map;
+
+    concatenation_map.reserve(files.size());
+    u64 last_offset = 0;
+
+    // Iteration of a multimap is ordered, so offset will be strictly non-decreasing.
+    for (auto& [offset, file] : files) {
+        const auto size = file->GetSize();
+
+        if (offset > last_offset) {
+            concatenation_map.emplace_back(ConcatenationEntry{
+                .offset = last_offset,
+                .file = std::make_shared<StaticVfsFile>(filler_byte, offset - last_offset),
+            });
+        }
+
+        concatenation_map.emplace_back(ConcatenationEntry{
+            .offset = offset,
+            .file = std::move(file),
+        });
+
+        last_offset = offset + size;
+    }
+
+    return VirtualFile(new ConcatenatedVfsFile(std::move(name), std::move(concatenation_map)));
+}
+
+std::string ConcatenatedVfsFile::GetName() const {
+    if (concatenation_map.empty()) {
+        return "";
+    }
+    if (!name.empty()) {
+        return name;
+    }
+    return concatenation_map.front().file->GetName();
+}
+
+std::size_t ConcatenatedVfsFile::GetSize() const {
+    if (concatenation_map.empty()) {
+        return 0;
+    }
+    return concatenation_map.back().offset + concatenation_map.back().file->GetSize();
+}
+
+bool ConcatenatedVfsFile::Resize(std::size_t new_size) {
+    return false;
+}
+
+VirtualDir ConcatenatedVfsFile::GetContainingDirectory() const {
+    if (concatenation_map.empty()) {
+        return nullptr;
+    }
+    return concatenation_map.front().file->GetContainingDirectory();
+}
+
+bool ConcatenatedVfsFile::IsWritable() const {
+    return false;
+}
+
+bool ConcatenatedVfsFile::IsReadable() const {
+    return true;
+}
+
+std::size_t ConcatenatedVfsFile::Read(u8* data, std::size_t length, std::size_t offset) const {
+    const ConcatenationEntry key{
+        .offset = offset,
+        .file = nullptr,
+    };
+
+    // Read nothing if the map is empty.
+    if (concatenation_map.empty()) {
+        return 0;
+    }
+
+    // Binary search to find the iterator to the first position we can check.
+    // It must exist, since we are not empty and are comparing unsigned integers.
+    auto it = std::prev(std::upper_bound(concatenation_map.begin(), concatenation_map.end(), key));
+    u64 cur_length = length;
+    u64 cur_offset = offset;
+
+    while (cur_length > 0 && it != concatenation_map.end()) {
+        // Check if we can read the file at this position.
+        const auto& file = it->file;
+        const u64 map_offset = it->offset;
+        const u64 file_size = file->GetSize();
+
+        if (cur_offset > map_offset + file_size) {
+            // Entirely out of bounds read.
+            break;
+        }
+
+        // Read the file at this position.
+        const u64 file_seek = cur_offset - map_offset;
+        const u64 intended_read_size = std::min<u64>(cur_length, file_size - file_seek);
+        const u64 actual_read_size =
+            file->Read(data + (cur_offset - offset), intended_read_size, file_seek);
+
+        // Update tracking.
+        cur_offset += actual_read_size;
+        cur_length -= actual_read_size;
+        it++;
+
+        // If we encountered a short read, we're done.
+        if (actual_read_size < intended_read_size) {
+            break;
+        }
+    }
+
+    return cur_offset - offset;
+}
+
+std::size_t ConcatenatedVfsFile::Write(const u8* data, std::size_t length, std::size_t offset) {
+    return 0;
+}
+
+bool ConcatenatedVfsFile::Rename(std::string_view new_name) {
+    return false;
+}
+
+} // namespace FileSys

src/core/file_sys/vfs/vfs_concat.h

@@ -0,0 +1,57 @@
+// SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <compare>
+#include <map>
+#include <memory>
+#include "core/file_sys/vfs/vfs.h"
+
+namespace FileSys {
+
+// Class that wraps multiple vfs files and concatenates them, making reads seamless. Currently
+// read-only.
+class ConcatenatedVfsFile : public VfsFile {
+private:
+    struct ConcatenationEntry {
+        u64 offset;
+        VirtualFile file;
+
+        auto operator<=>(const ConcatenationEntry& other) const {
+            return this->offset <=> other.offset;
+        }
+    };
+    using ConcatenationMap = std::vector<ConcatenationEntry>;
+
+    explicit ConcatenatedVfsFile(std::string&& name,
+                                 std::vector<ConcatenationEntry>&& concatenation_map);
+    bool VerifyContinuity() const;
+
+public:
+    ~ConcatenatedVfsFile() override;
+
+    /// Wrapper function to allow for more efficient handling of files.size() == 0, 1 cases.
+    static VirtualFile MakeConcatenatedFile(std::string&& name, std::vector<VirtualFile>&& files);
+
+    /// Convenience function that turns a map of offsets to files into a concatenated file, filling
+    /// gaps with a given filler byte.
+    static VirtualFile MakeConcatenatedFile(u8 filler_byte, std::string&& name,
+                                            std::vector<std::pair<u64, VirtualFile>>&& files);
+
+    std::string GetName() const override;
+    std::size_t GetSize() const override;
+    bool Resize(std::size_t new_size) override;
+    VirtualDir GetContainingDirectory() const override;
+    bool IsWritable() const override;
+    bool IsReadable() const override;
+    std::size_t Read(u8* data, std::size_t length, std::size_t offset) const override;
+    std::size_t Write(const u8* data, std::size_t length, std::size_t offset) override;
+    bool Rename(std::string_view new_name) override;
+
+private:
+    ConcatenationMap concatenation_map;
+    std::string name;
+};
+
+} // namespace FileSys

src/core/file_sys/vfs/vfs_layered.cpp

@@ -0,0 +1,132 @@
+// SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <algorithm>
+#include <set>
+#include <unordered_set>
+#include <utility>
+#include "core/file_sys/vfs/vfs_layered.h"
+
+namespace FileSys {
+
+LayeredVfsDirectory::LayeredVfsDirectory(std::vector<VirtualDir> dirs_, std::string name_)
+    : dirs(std::move(dirs_)), name(std::move(name_)) {}
+
+LayeredVfsDirectory::~LayeredVfsDirectory() = default;
+
+VirtualDir LayeredVfsDirectory::MakeLayeredDirectory(std::vector<VirtualDir> dirs,
+                                                     std::string name) {
+    if (dirs.empty())
+        return nullptr;
+    if (dirs.size() == 1)
+        return dirs[0];
+
+    return VirtualDir(new LayeredVfsDirectory(std::move(dirs), std::move(name)));
+}
+
+VirtualFile LayeredVfsDirectory::GetFileRelative(std::string_view path) const {
+    for (const auto& layer : dirs) {
+        const auto file = layer->GetFileRelative(path);
+        if (file != nullptr)
+            return file;
+    }
+
+    return nullptr;
+}
+
+VirtualDir LayeredVfsDirectory::GetDirectoryRelative(std::string_view path) const {
+    std::vector<VirtualDir> out;
+    for (const auto& layer : dirs) {
+        auto dir = layer->GetDirectoryRelative(path);
+        if (dir != nullptr) {
+            out.emplace_back(std::move(dir));
+        }
+    }
+
+    return MakeLayeredDirectory(std::move(out));
+}
+
+VirtualFile LayeredVfsDirectory::GetFile(std::string_view file_name) const {
+    return GetFileRelative(file_name);
+}
+
+VirtualDir LayeredVfsDirectory::GetSubdirectory(std::string_view subdir_name) const {
+    return GetDirectoryRelative(subdir_name);
+}
+
+std::string LayeredVfsDirectory::GetFullPath() const {
+    return dirs[0]->GetFullPath();
+}
+
+std::vector<VirtualFile> LayeredVfsDirectory::GetFiles() const {
+    std::vector<VirtualFile> out;
+    std::unordered_set<std::string> out_names;
+
+    for (const auto& layer : dirs) {
+        for (auto& file : layer->GetFiles()) {
+            const auto [it, is_new] = out_names.emplace(file->GetName());
+            if (is_new) {
+                out.emplace_back(std::move(file));
+            }
+        }
+    }
+
+    return out;
+}
+
+std::vector<VirtualDir> LayeredVfsDirectory::GetSubdirectories() const {
+    std::vector<VirtualDir> out;
+    std::unordered_set<std::string> out_names;
+
+    for (const auto& layer : dirs) {
+        for (const auto& sd : layer->GetSubdirectories()) {
+            out_names.emplace(sd->GetName());
+        }
+    }
+
+    out.reserve(out_names.size());
+    for (const auto& subdir : out_names) {
+        out.emplace_back(GetSubdirectory(subdir));
+    }
+
+    return out;
+}
+
+bool LayeredVfsDirectory::IsWritable() const {
+    return false;
+}
+
+bool LayeredVfsDirectory::IsReadable() const {
+    return true;
+}
+
+std::string LayeredVfsDirectory::GetName() const {
+    return name.empty() ? dirs[0]->GetName() : name;
+}
+
+VirtualDir LayeredVfsDirectory::GetParentDirectory() const {
+    return dirs[0]->GetParentDirectory();
+}
+
+VirtualDir LayeredVfsDirectory::CreateSubdirectory(std::string_view subdir_name) {
+    return nullptr;
+}
+
+VirtualFile LayeredVfsDirectory::CreateFile(std::string_view file_name) {
+    return nullptr;
+}
+
+bool LayeredVfsDirectory::DeleteSubdirectory(std::string_view subdir_name) {
+    return false;
+}
+
+bool LayeredVfsDirectory::DeleteFile(std::string_view file_name) {
+    return false;
+}
+
+bool LayeredVfsDirectory::Rename(std::string_view new_name) {
+    name = new_name;
+    return true;
+}
+
+} // namespace FileSys

src/core/file_sys/vfs/vfs_layered.h

@@ -0,0 +1,46 @@
+// SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <memory>
+#include "core/file_sys/vfs/vfs.h"
+
+namespace FileSys {
+
+// Class that stacks multiple VfsDirectories on top of each other, attempting to read from the first
+// one and falling back to the one after. The highest priority directory (overwrites all others)
+// should be element 0 in the dirs vector.
+class LayeredVfsDirectory : public VfsDirectory {
+    explicit LayeredVfsDirectory(std::vector<VirtualDir> dirs_, std::string name_);
+
+public:
+    ~LayeredVfsDirectory() override;
+
+    /// Wrapper function to allow for more efficient handling of dirs.size() == 0, 1 cases.
+    static VirtualDir MakeLayeredDirectory(std::vector<VirtualDir> dirs, std::string name = "");
+
+    VirtualFile GetFileRelative(std::string_view path) const override;
+    VirtualDir GetDirectoryRelative(std::string_view path) const override;
+    VirtualFile GetFile(std::string_view file_name) const override;
+    VirtualDir GetSubdirectory(std::string_view subdir_name) const override;
+    std::string GetFullPath() const override;
+
+    std::vector<VirtualFile> GetFiles() const override;
+    std::vector<VirtualDir> GetSubdirectories() const override;
+    bool IsWritable() const override;
+    bool IsReadable() const override;
+    std::string GetName() const override;
+    VirtualDir GetParentDirectory() const override;
+    VirtualDir CreateSubdirectory(std::string_view subdir_name) override;
+    VirtualFile CreateFile(std::string_view file_name) override;
+    bool DeleteSubdirectory(std::string_view subdir_name) override;
+    bool DeleteFile(std::string_view file_name) override;
+    bool Rename(std::string_view new_name) override;
+
+private:
+    std::vector<VirtualDir> dirs;
+    std::string name;
+};
+
+} // namespace FileSys

src/core/file_sys/vfs/vfs_offset.cpp

@@ -0,0 +1,98 @@
+// SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <algorithm>
+#include <utility>
+
+#include "core/file_sys/vfs/vfs_offset.h"
+
+namespace FileSys {
+
+OffsetVfsFile::OffsetVfsFile(VirtualFile file_, std::size_t size_, std::size_t offset_,
+                             std::string name_, VirtualDir parent_)
+    : file(file_), offset(offset_), size(size_), name(std::move(name_)),
+      parent(parent_ == nullptr ? file->GetContainingDirectory() : std::move(parent_)) {}
+
+OffsetVfsFile::~OffsetVfsFile() = default;
+
+std::string OffsetVfsFile::GetName() const {
+    return name.empty() ? file->GetName() : name;
+}
+
+std::size_t OffsetVfsFile::GetSize() const {
+    return size;
+}
+
+bool OffsetVfsFile::Resize(std::size_t new_size) {
+    if (offset + new_size < file->GetSize()) {
+        size = new_size;
+    } else {
+        auto res = file->Resize(offset + new_size);
+        if (!res)
+            return false;
+        size = new_size;
+    }
+
+    return true;
+}
+
+VirtualDir OffsetVfsFile::GetContainingDirectory() const {
+    return parent;
+}
+
+bool OffsetVfsFile::IsWritable() const {
+    return file->IsWritable();
+}
+
+bool OffsetVfsFile::IsReadable() const {
+    return file->IsReadable();
+}
+
+std::size_t OffsetVfsFile::Read(u8* data, std::size_t length, std::size_t r_offset) const {
+    return file->Read(data, TrimToFit(length, r_offset), offset + r_offset);
+}
+
+std::size_t OffsetVfsFile::Write(const u8* data, std::size_t length, std::size_t r_offset) {
+    return file->Write(data, TrimToFit(length, r_offset), offset + r_offset);
+}
+
+std::optional<u8> OffsetVfsFile::ReadByte(std::size_t r_offset) const {
+    if (r_offset >= size) {
+        return std::nullopt;
+    }
+
+    return file->ReadByte(offset + r_offset);
+}
+
+std::vector<u8> OffsetVfsFile::ReadBytes(std::size_t r_size, std::size_t r_offset) const {
+    return file->ReadBytes(TrimToFit(r_size, r_offset), offset + r_offset);
+}
+
+std::vector<u8> OffsetVfsFile::ReadAllBytes() const {
+    return file->ReadBytes(size, offset);
+}
+
+bool OffsetVfsFile::WriteByte(u8 data, std::size_t r_offset) {
+    if (r_offset < size)
+        return file->WriteByte(data, offset + r_offset);
+
+    return false;
+}
+
+std::size_t OffsetVfsFile::WriteBytes(const std::vector<u8>& data, std::size_t r_offset) {
+    return file->Write(data.data(), TrimToFit(data.size(), r_offset), offset + r_offset);
+}
+
+bool OffsetVfsFile::Rename(std::string_view new_name) {
+    return file->Rename(new_name);
+}
+
+std::size_t OffsetVfsFile::GetOffset() const {
+    return offset;
+}
+
+std::size_t OffsetVfsFile::TrimToFit(std::size_t r_size, std::size_t r_offset) const {
+    return std::clamp(r_size, std::size_t{0}, size - r_offset);
+}
+
+} // namespace FileSys

src/core/file_sys/vfs/vfs_offset.h

@@ -0,0 +1,50 @@
+// SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <memory>
+
+#include "core/file_sys/vfs/vfs.h"
+
+namespace FileSys {
+
+// An implementation of VfsFile that wraps around another VfsFile at a certain offset.
+// Similar to seeking to an offset.
+// If the file is writable, operations that would write past the end of the offset file will expand
+// the size of this wrapper.
+class OffsetVfsFile : public VfsFile {
+public:
+    OffsetVfsFile(VirtualFile file, std::size_t size, std::size_t offset = 0,
+                  std::string new_name = "", VirtualDir new_parent = nullptr);
+    ~OffsetVfsFile() override;
+
+    std::string GetName() const override;
+    std::size_t GetSize() const override;
+    bool Resize(std::size_t new_size) override;
+    VirtualDir GetContainingDirectory() const override;
+    bool IsWritable() const override;
+    bool IsReadable() const override;
+    std::size_t Read(u8* data, std::size_t length, std::size_t offset) const override;
+    std::size_t Write(const u8* data, std::size_t length, std::size_t offset) override;
+    std::optional<u8> ReadByte(std::size_t offset) const override;
+    std::vector<u8> ReadBytes(std::size_t size, std::size_t offset) const override;
+    std::vector<u8> ReadAllBytes() const override;
+    bool WriteByte(u8 data, std::size_t offset) override;
+    std::size_t WriteBytes(const std::vector<u8>& data, std::size_t offset) override;
+
+    bool Rename(std::string_view new_name) override;
+
+    std::size_t GetOffset() const;
+
+private:
+    std::size_t TrimToFit(std::size_t r_size, std::size_t r_offset) const;
+
+    VirtualFile file;
+    std::size_t offset;
+    std::size_t size;
+    std::string name;
+    VirtualDir parent;
+};
+
+} // namespace FileSys

src/core/file_sys/vfs/vfs_real.cpp

@@ -0,0 +1,527 @@
+// SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <algorithm>
+#include <cstddef>
+#include <iterator>
+#include <utility>
+#include "common/assert.h"
+#include "common/fs/file.h"
+#include "common/fs/fs.h"
+#include "common/fs/path_util.h"
+#include "common/logging/log.h"
+#include "core/file_sys/vfs/vfs.h"
+#include "core/file_sys/vfs/vfs_real.h"
+
+// For FileTimeStampRaw
+#include <sys/stat.h>
+
+#ifdef _MSC_VER
+#define stat _stat64
+#endif
+
+namespace FileSys {
+
+namespace FS = Common::FS;
+
+namespace {
+
+constexpr size_t MaxOpenFiles = 512;
+
+constexpr FS::FileAccessMode ModeFlagsToFileAccessMode(OpenMode mode) {
+    switch (mode) {
+    case OpenMode::Read:
+        return FS::FileAccessMode::Read;
+    case OpenMode::Write:
+    case OpenMode::ReadWrite:
+    case OpenMode::AllowAppend:
+    case OpenMode::All:
+        return FS::FileAccessMode::ReadWrite;
+    default:
+        return {};
+    }
+}
+
+} // Anonymous namespace
+
+RealVfsFilesystem::RealVfsFilesystem() : VfsFilesystem(nullptr) {}
+RealVfsFilesystem::~RealVfsFilesystem() = default;
+
+std::string RealVfsFilesystem::GetName() const {
+    return "Real";
+}
+
+bool RealVfsFilesystem::IsReadable() const {
+    return true;
+}
+
+bool RealVfsFilesystem::IsWritable() const {
+    return true;
+}
+
+VfsEntryType RealVfsFilesystem::GetEntryType(std::string_view path_) const {
+    const auto path = FS::SanitizePath(path_, FS::DirectorySeparator::PlatformDefault);
+    if (!FS::Exists(path)) {
+        return VfsEntryType::None;
+    }
+    if (FS::IsDir(path)) {
+        return VfsEntryType::Directory;
+    }
+
+    return VfsEntryType::File;
+}
+
+VirtualFile RealVfsFilesystem::OpenFileFromEntry(std::string_view path_, std::optional<u64> size,
+                                                 OpenMode perms) {
+    const auto path = FS::SanitizePath(path_, FS::DirectorySeparator::PlatformDefault);
+    std::scoped_lock lk{list_lock};
+
+    if (auto it = cache.find(path); it != cache.end()) {
+        if (auto file = it->second.lock(); file) {
+            return file;
+        }
+    }
+
+    if (!size && !FS::IsFile(path)) {
+        return nullptr;
+    }
+
+    auto reference = std::make_unique<FileReference>();
+    this->InsertReferenceIntoListLocked(*reference);
+
+    auto file = std::shared_ptr<RealVfsFile>(
+        new RealVfsFile(*this, std::move(reference), path, perms, size));
+    cache[path] = file;
+
+    return file;
+}
+
+VirtualFile RealVfsFilesystem::OpenFile(std::string_view path_, OpenMode perms) {
+    return OpenFileFromEntry(path_, {}, perms);
+}
+
+VirtualFile RealVfsFilesystem::CreateFile(std::string_view path_, OpenMode perms) {
+    const auto path = FS::SanitizePath(path_, FS::DirectorySeparator::PlatformDefault);
+    {
+        std::scoped_lock lk{list_lock};
+        cache.erase(path);
+    }
+
+    // Current usages of CreateFile expect to delete the contents of an existing file.
+    if (FS::IsFile(path)) {
+        FS::IOFile temp{path, FS::FileAccessMode::Write, FS::FileType::BinaryFile};
+
+        if (!temp.IsOpen()) {
+            return nullptr;
+        }
+
+        temp.Close();
+
+        return OpenFile(path, perms);
+    }
+
+    if (!FS::NewFile(path)) {
+        return nullptr;
+    }
+
+    return OpenFile(path, perms);
+}
+
+VirtualFile RealVfsFilesystem::CopyFile(std::string_view old_path_, std::string_view new_path_) {
+    // Unused
+    return nullptr;
+}
+
+VirtualFile RealVfsFilesystem::MoveFile(std::string_view old_path_, std::string_view new_path_) {
+    const auto old_path = FS::SanitizePath(old_path_, FS::DirectorySeparator::PlatformDefault);
+    const auto new_path = FS::SanitizePath(new_path_, FS::DirectorySeparator::PlatformDefault);
+    {
+        std::scoped_lock lk{list_lock};
+        cache.erase(old_path);
+        cache.erase(new_path);
+    }
+    if (!FS::RenameFile(old_path, new_path)) {
+        return nullptr;
+    }
+    return OpenFile(new_path, OpenMode::ReadWrite);
+}
+
+bool RealVfsFilesystem::DeleteFile(std::string_view path_) {
+    const auto path = FS::SanitizePath(path_, FS::DirectorySeparator::PlatformDefault);
+    {
+        std::scoped_lock lk{list_lock};
+        cache.erase(path);
+    }
+    return FS::RemoveFile(path);
+}
+
+VirtualDir RealVfsFilesystem::OpenDirectory(std::string_view path_, OpenMode perms) {
+    const auto path = FS::SanitizePath(path_, FS::DirectorySeparator::PlatformDefault);
+    return std::shared_ptr<RealVfsDirectory>(new RealVfsDirectory(*this, path, perms));
+}
+
+VirtualDir RealVfsFilesystem::CreateDirectory(std::string_view path_, OpenMode perms) {
+    const auto path = FS::SanitizePath(path_, FS::DirectorySeparator::PlatformDefault);
+    if (!FS::CreateDirs(path)) {
+        return nullptr;
+    }
+    return std::shared_ptr<RealVfsDirectory>(new RealVfsDirectory(*this, path, perms));
+}
+
+VirtualDir RealVfsFilesystem::CopyDirectory(std::string_view old_path_,
+                                            std::string_view new_path_) {
+    // Unused
+    return nullptr;
+}
+
+VirtualDir RealVfsFilesystem::MoveDirectory(std::string_view old_path_,
+                                            std::string_view new_path_) {
+    const auto old_path = FS::SanitizePath(old_path_, FS::DirectorySeparator::PlatformDefault);
+    const auto new_path = FS::SanitizePath(new_path_, FS::DirectorySeparator::PlatformDefault);
+
+    if (!FS::RenameDir(old_path, new_path)) {
+        return nullptr;
+    }
+    return OpenDirectory(new_path, OpenMode::ReadWrite);
+}
+
+bool RealVfsFilesystem::DeleteDirectory(std::string_view path_) {
+    const auto path = FS::SanitizePath(path_, FS::DirectorySeparator::PlatformDefault);
+    return FS::RemoveDirRecursively(path);
+}
+
+std::unique_lock<std::mutex> RealVfsFilesystem::RefreshReference(const std::string& path,
+                                                                 OpenMode perms,
+                                                                 FileReference& reference) {
+    std::unique_lock lk{list_lock};
+
+    // Temporarily remove from list.
+    this->RemoveReferenceFromListLocked(reference);
+
+    // Restore file if needed.
+    if (!reference.file) {
+        this->EvictSingleReferenceLocked();
+
+        reference.file =
+            FS::FileOpen(path, ModeFlagsToFileAccessMode(perms), FS::FileType::BinaryFile);
+        if (reference.file) {
+            num_open_files++;
+        }
+    }
+
+    // Reinsert into list.
+    this->InsertReferenceIntoListLocked(reference);
+
+    return lk;
+}
+
+void RealVfsFilesystem::DropReference(std::unique_ptr<FileReference>&& reference) {
+    std::scoped_lock lk{list_lock};
+
+    // Remove from list.
+    this->RemoveReferenceFromListLocked(*reference);
+
+    // Close the file.
+    if (reference->file) {
+        reference->file.reset();
+        num_open_files--;
+    }
+}
+
+void RealVfsFilesystem::EvictSingleReferenceLocked() {
+    if (num_open_files < MaxOpenFiles || open_references.empty()) {
+        return;
+    }
+
+    // Get and remove from list.
+    auto& reference = open_references.back();
+    this->RemoveReferenceFromListLocked(reference);
+
+    // Close the file.
+    if (reference.file) {
+        reference.file.reset();
+        num_open_files--;
+    }
+
+    // Reinsert into closed list.
+    this->InsertReferenceIntoListLocked(reference);
+}
+
+void RealVfsFilesystem::InsertReferenceIntoListLocked(FileReference& reference) {
+    if (reference.file) {
+        open_references.push_front(reference);
+    } else {
+        closed_references.push_front(reference);
+    }
+}
+
+void RealVfsFilesystem::RemoveReferenceFromListLocked(FileReference& reference) {
+    if (reference.file) {
+        open_references.erase(open_references.iterator_to(reference));
+    } else {
+        closed_references.erase(closed_references.iterator_to(reference));
+    }
+}
+
+RealVfsFile::RealVfsFile(RealVfsFilesystem& base_, std::unique_ptr<FileReference> reference_,
+                         const std::string& path_, OpenMode perms_, std::optional<u64> size_)
+    : base(base_), reference(std::move(reference_)), path(path_),
+      parent_path(FS::GetParentPath(path_)), path_components(FS::SplitPathComponentsCopy(path_)),
+      size(size_), perms(perms_) {}
+
+RealVfsFile::~RealVfsFile() {
+    base.DropReference(std::move(reference));
+}
+
+std::string RealVfsFile::GetName() const {
+    return path_components.empty() ? "" : std::string(path_components.back());
+}
+
+std::size_t RealVfsFile::GetSize() const {
+    if (size) {
+        return *size;
+    }
+    auto lk = base.RefreshReference(path, perms, *reference);
+    return reference->file ? reference->file->GetSize() : 0;
+}
+
+bool RealVfsFile::Resize(std::size_t new_size) {
+    size.reset();
+    auto lk = base.RefreshReference(path, perms, *reference);
+    return reference->file ? reference->file->SetSize(new_size) : false;
+}
+
+VirtualDir RealVfsFile::GetContainingDirectory() const {
+    return base.OpenDirectory(parent_path, perms);
+}
+
+bool RealVfsFile::IsWritable() const {
+    return True(perms & OpenMode::Write);
+}
+
+bool RealVfsFile::IsReadable() const {
+    return True(perms & OpenMode::Read);
+}
+
+std::size_t RealVfsFile::Read(u8* data, std::size_t length, std::size_t offset) const {
+    auto lk = base.RefreshReference(path, perms, *reference);
+    if (!reference->file || !reference->file->Seek(static_cast<s64>(offset))) {
+        return 0;
+    }
+    return reference->file->ReadSpan(std::span{data, length});
+}
+
+std::size_t RealVfsFile::Write(const u8* data, std::size_t length, std::size_t offset) {
+    size.reset();
+    auto lk = base.RefreshReference(path, perms, *reference);
+    if (!reference->file || !reference->file->Seek(static_cast<s64>(offset))) {
+        return 0;
+    }
+    return reference->file->WriteSpan(std::span{data, length});
+}
+
+bool RealVfsFile::Rename(std::string_view name) {
+    return base.MoveFile(path, parent_path + '/' + std::string(name)) != nullptr;
+}
+
+// TODO(DarkLordZach): MSVC would not let me combine the following two functions using 'if
+// constexpr' because there is a compile error in the branch not used.
+
+template <>
+std::vector<VirtualFile> RealVfsDirectory::IterateEntries<RealVfsFile, VfsFile>() const {
+    if (perms == OpenMode::AllowAppend) {
+        return {};
+    }
+
+    std::vector<VirtualFile> out;
+
+    const FS::DirEntryCallable callback = [this,
+                                           &out](const std::filesystem::directory_entry& entry) {
+        const auto full_path_string = FS::PathToUTF8String(entry.path());
+
+        out.emplace_back(base.OpenFileFromEntry(full_path_string, entry.file_size(), perms));
+
+        return true;
+    };
+
+    FS::IterateDirEntries(path, callback, FS::DirEntryFilter::File);
+
+    return out;
+}
+
+template <>
+std::vector<VirtualDir> RealVfsDirectory::IterateEntries<RealVfsDirectory, VfsDirectory>() const {
+    if (perms == OpenMode::AllowAppend) {
+        return {};
+    }
+
+    std::vector<VirtualDir> out;
+
+    const FS::DirEntryCallable callback = [this,
+                                           &out](const std::filesystem::directory_entry& entry) {
+        const auto full_path_string = FS::PathToUTF8String(entry.path());
+
+        out.emplace_back(base.OpenDirectory(full_path_string, perms));
+
+        return true;
+    };
+
+    FS::IterateDirEntries(path, callback, FS::DirEntryFilter::Directory);
+
+    return out;
+}
+
+RealVfsDirectory::RealVfsDirectory(RealVfsFilesystem& base_, const std::string& path_,
+                                   OpenMode perms_)
+    : base(base_), path(FS::RemoveTrailingSlash(path_)), parent_path(FS::GetParentPath(path)),
+      path_components(FS::SplitPathComponentsCopy(path)), perms(perms_) {
+    if (!FS::Exists(path) && True(perms & OpenMode::Write)) {
+        void(FS::CreateDirs(path));
+    }
+}
+
+RealVfsDirectory::~RealVfsDirectory() = default;
+
+VirtualFile RealVfsDirectory::GetFileRelative(std::string_view relative_path) const {
+    const auto full_path = FS::SanitizePath(path + '/' + std::string(relative_path));
+    if (!FS::Exists(full_path) || FS::IsDir(full_path)) {
+        return nullptr;
+    }
+    return base.OpenFile(full_path, perms);
+}
+
+VirtualDir RealVfsDirectory::GetDirectoryRelative(std::string_view relative_path) const {
+    const auto full_path = FS::SanitizePath(path + '/' + std::string(relative_path));
+    if (!FS::Exists(full_path) || !FS::IsDir(full_path)) {
+        return nullptr;
+    }
+    return base.OpenDirectory(full_path, perms);
+}
+
+VirtualFile RealVfsDirectory::GetFile(std::string_view name) const {
+    return GetFileRelative(name);
+}
+
+VirtualDir RealVfsDirectory::GetSubdirectory(std::string_view name) const {
+    return GetDirectoryRelative(name);
+}
+
+VirtualFile RealVfsDirectory::CreateFileRelative(std::string_view relative_path) {
+    const auto full_path = FS::SanitizePath(path + '/' + std::string(relative_path));
+    if (!FS::CreateParentDirs(full_path)) {
+        return nullptr;
+    }
+    return base.CreateFile(full_path, perms);
+}
+
+VirtualDir RealVfsDirectory::CreateDirectoryRelative(std::string_view relative_path) {
+    const auto full_path = FS::SanitizePath(path + '/' + std::string(relative_path));
+    return base.CreateDirectory(full_path, perms);
+}
+
+bool RealVfsDirectory::DeleteSubdirectoryRecursive(std::string_view name) {
+    const auto full_path = FS::SanitizePath(this->path + '/' + std::string(name));
+    return base.DeleteDirectory(full_path);
+}
+
+std::vector<VirtualFile> RealVfsDirectory::GetFiles() const {
+    return IterateEntries<RealVfsFile, VfsFile>();
+}
+
+FileTimeStampRaw RealVfsDirectory::GetFileTimeStamp(std::string_view path_) const {
+    const auto full_path = FS::SanitizePath(path + '/' + std::string(path_));
+    const auto fs_path = std::filesystem::path{FS::ToU8String(full_path)};
+    struct stat file_status;
+
+#ifdef _WIN32
+    const auto stat_result = _wstat64(fs_path.c_str(), &file_status);
+#else
+    const auto stat_result = stat(fs_path.c_str(), &file_status);
+#endif
+
+    if (stat_result != 0) {
+        return {};
+    }
+
+    return {
+        .created{static_cast<u64>(file_status.st_ctime)},
+        .accessed{static_cast<u64>(file_status.st_atime)},
+        .modified{static_cast<u64>(file_status.st_mtime)},
+    };
+}
+
+std::vector<VirtualDir> RealVfsDirectory::GetSubdirectories() const {
+    return IterateEntries<RealVfsDirectory, VfsDirectory>();
+}
+
+bool RealVfsDirectory::IsWritable() const {
+    return True(perms & OpenMode::Write);
+}
+
+bool RealVfsDirectory::IsReadable() const {
+    return True(perms & OpenMode::Read);
+}
+
+std::string RealVfsDirectory::GetName() const {
+    return path_components.empty() ? "" : std::string(path_components.back());
+}
+
+VirtualDir RealVfsDirectory::GetParentDirectory() const {
+    if (path_components.size() <= 1) {
+        return nullptr;
+    }
+
+    return base.OpenDirectory(parent_path, perms);
+}
+
+VirtualDir RealVfsDirectory::CreateSubdirectory(std::string_view name) {
+    const std::string subdir_path = (path + '/').append(name);
+    return base.CreateDirectory(subdir_path, perms);
+}
+
+VirtualFile RealVfsDirectory::CreateFile(std::string_view name) {
+    const std::string file_path = (path + '/').append(name);
+    return base.CreateFile(file_path, perms);
+}
+
+bool RealVfsDirectory::DeleteSubdirectory(std::string_view name) {
+    const std::string subdir_path = (path + '/').append(name);
+    return base.DeleteDirectory(subdir_path);
+}
+
+bool RealVfsDirectory::DeleteFile(std::string_view name) {
+    const std::string file_path = (path + '/').append(name);
+    return base.DeleteFile(file_path);
+}
+
+bool RealVfsDirectory::Rename(std::string_view name) {
+    const std::string new_name = (parent_path + '/').append(name);
+    return base.MoveFile(path, new_name) != nullptr;
+}
+
+std::string RealVfsDirectory::GetFullPath() const {
+    auto out = path;
+    std::replace(out.begin(), out.end(), '\\', '/');
+    return out;
+}
+
+std::map<std::string, VfsEntryType, std::less<>> RealVfsDirectory::GetEntries() const {
+    if (perms == OpenMode::AllowAppend) {
+        return {};
+    }
+
+    std::map<std::string, VfsEntryType, std::less<>> out;
+
+    const FS::DirEntryCallable callback = [&out](const std::filesystem::directory_entry& entry) {
+        const auto filename = FS::PathToUTF8String(entry.path().filename());
+        out.insert_or_assign(filename,
+                             entry.is_directory() ? VfsEntryType::Directory : VfsEntryType::File);
+        return true;
+    };
+
+    FS::IterateDirEntries(path, callback);
+
+    return out;
+}
+
+} // namespace FileSys

src/core/file_sys/vfs/vfs_real.h

@@ -0,0 +1,148 @@
+// SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <map>
+#include <mutex>
+#include <optional>
+#include <string_view>
+#include "common/intrusive_list.h"
+#include "core/file_sys/fs_filesystem.h"
+#include "core/file_sys/vfs/vfs.h"
+
+namespace Common::FS {
+class IOFile;
+}
+
+namespace FileSys {
+
+struct FileReference : public Common::IntrusiveListBaseNode<FileReference> {
+    std::shared_ptr<Common::FS::IOFile> file{};
+};
+
+class RealVfsFile;
+class RealVfsDirectory;
+
+class RealVfsFilesystem : public VfsFilesystem {
+public:
+    RealVfsFilesystem();
+    ~RealVfsFilesystem() override;
+
+    std::string GetName() const override;
+    bool IsReadable() const override;
+    bool IsWritable() const override;
+    VfsEntryType GetEntryType(std::string_view path) const override;
+    VirtualFile OpenFile(std::string_view path, OpenMode perms = OpenMode::Read) override;
+    VirtualFile CreateFile(std::string_view path, OpenMode perms = OpenMode::ReadWrite) override;
+    VirtualFile CopyFile(std::string_view old_path, std::string_view new_path) override;
+    VirtualFile MoveFile(std::string_view old_path, std::string_view new_path) override;
+    bool DeleteFile(std::string_view path) override;
+    VirtualDir OpenDirectory(std::string_view path, OpenMode perms = OpenMode::Read) override;
+    VirtualDir CreateDirectory(std::string_view path,
+                               OpenMode perms = OpenMode::ReadWrite) override;
+    VirtualDir CopyDirectory(std::string_view old_path, std::string_view new_path) override;
+    VirtualDir MoveDirectory(std::string_view old_path, std::string_view new_path) override;
+    bool DeleteDirectory(std::string_view path) override;
+
+private:
+    using ReferenceListType = Common::IntrusiveListBaseTraits<FileReference>::ListType;
+    std::map<std::string, std::weak_ptr<VfsFile>, std::less<>> cache;
+    ReferenceListType open_references;
+    ReferenceListType closed_references;
+    std::mutex list_lock;
+    size_t num_open_files{};
+
+private:
+    friend class RealVfsFile;
+    std::unique_lock<std::mutex> RefreshReference(const std::string& path, OpenMode perms,
+                                                  FileReference& reference);
+    void DropReference(std::unique_ptr<FileReference>&& reference);
+
+private:
+    friend class RealVfsDirectory;
+    VirtualFile OpenFileFromEntry(std::string_view path, std::optional<u64> size,
+                                  OpenMode perms = OpenMode::Read);
+
+private:
+    void EvictSingleReferenceLocked();
+    void InsertReferenceIntoListLocked(FileReference& reference);
+    void RemoveReferenceFromListLocked(FileReference& reference);
+};
+
+// An implementation of VfsFile that represents a file on the user's computer.
+class RealVfsFile : public VfsFile {
+    friend class RealVfsDirectory;
+    friend class RealVfsFilesystem;
+
+public:
+    ~RealVfsFile() override;
+
+    std::string GetName() const override;
+    std::size_t GetSize() const override;
+    bool Resize(std::size_t new_size) override;
+    VirtualDir GetContainingDirectory() const override;
+    bool IsWritable() const override;
+    bool IsReadable() const override;
+    std::size_t Read(u8* data, std::size_t length, std::size_t offset) const override;
+    std::size_t Write(const u8* data, std::size_t length, std::size_t offset) override;
+    bool Rename(std::string_view name) override;
+
+private:
+    RealVfsFile(RealVfsFilesystem& base, std::unique_ptr<FileReference> reference,
+                const std::string& path, OpenMode perms = OpenMode::Read,
+                std::optional<u64> size = {});
+
+    RealVfsFilesystem& base;
+    std::unique_ptr<FileReference> reference;
+    std::string path;
+    std::string parent_path;
+    std::vector<std::string> path_components;
+    std::optional<u64> size;
+    OpenMode perms;
+};
+
+// An implementation of VfsDirectory that represents a directory on the user's computer.
+class RealVfsDirectory : public VfsDirectory {
+    friend class RealVfsFilesystem;
+
+public:
+    ~RealVfsDirectory() override;
+
+    VirtualFile GetFileRelative(std::string_view relative_path) const override;
+    VirtualDir GetDirectoryRelative(std::string_view relative_path) const override;
+    VirtualFile GetFile(std::string_view name) const override;
+    VirtualDir GetSubdirectory(std::string_view name) const override;
+    VirtualFile CreateFileRelative(std::string_view relative_path) override;
+    VirtualDir CreateDirectoryRelative(std::string_view relative_path) override;
+    bool DeleteSubdirectoryRecursive(std::string_view name) override;
+    std::vector<VirtualFile> GetFiles() const override;
+    FileTimeStampRaw GetFileTimeStamp(std::string_view path) const override;
+    std::vector<VirtualDir> GetSubdirectories() const override;
+    bool IsWritable() const override;
+    bool IsReadable() const override;
+    std::string GetName() const override;
+    VirtualDir GetParentDirectory() const override;
+    VirtualDir CreateSubdirectory(std::string_view name) override;
+    VirtualFile CreateFile(std::string_view name) override;
+    bool DeleteSubdirectory(std::string_view name) override;
+    bool DeleteFile(std::string_view name) override;
+    bool Rename(std::string_view name) override;
+    std::string GetFullPath() const override;
+    std::map<std::string, VfsEntryType, std::less<>> GetEntries() const override;
+
+private:
+    RealVfsDirectory(RealVfsFilesystem& base, const std::string& path,
+                     OpenMode perms = OpenMode::Read);
+
+    template <typename T, typename R>
+    std::vector<std::shared_ptr<R>> IterateEntries() const;
+
+    RealVfsFilesystem& base;
+    std::string path;
+    std::string parent_path;
+    std::vector<std::string> path_components;
+    OpenMode perms;
+};
+
+} // namespace FileSys

src/core/file_sys/vfs/vfs_static.h

@@ -0,0 +1,80 @@
+// SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <algorithm>
+#include <memory>
+#include <string_view>
+
+#include "core/file_sys/vfs/vfs.h"
+
+namespace FileSys {
+
+class StaticVfsFile : public VfsFile {
+public:
+    explicit StaticVfsFile(u8 value_, std::size_t size_ = 0, std::string name_ = "",
+                           VirtualDir parent_ = nullptr)
+        : value{value_}, size{size_}, name{std::move(name_)}, parent{std::move(parent_)} {}
+
+    std::string GetName() const override {
+        return name;
+    }
+
+    std::size_t GetSize() const override {
+        return size;
+    }
+
+    bool Resize(std::size_t new_size) override {
+        size = new_size;
+        return true;
+    }
+
+    VirtualDir GetContainingDirectory() const override {
+        return parent;
+    }
+
+    bool IsWritable() const override {
+        return false;
+    }
+
+    bool IsReadable() const override {
+        return true;
+    }
+
+    std::size_t Read(u8* data, std::size_t length, std::size_t offset) const override {
+        const auto read = std::min(length, size - offset);
+        std::fill(data, data + read, value);
+        return read;
+    }
+
+    std::size_t Write(const u8* data, std::size_t length, std::size_t offset) override {
+        return 0;
+    }
+
+    std::optional<u8> ReadByte(std::size_t offset) const override {
+        if (offset >= size) {
+            return std::nullopt;
+        }
+
+        return value;
+    }
+
+    std::vector<u8> ReadBytes(std::size_t length, std::size_t offset) const override {
+        const auto read = std::min(length, size - offset);
+        return std::vector<u8>(read, value);
+    }
+
+    bool Rename(std::string_view new_name) override {
+        name = new_name;
+        return true;
+    }
+
+private:
+    u8 value;
+    std::size_t size;
+    std::string name;
+    VirtualDir parent;
+};
+
+} // namespace FileSys