Implement ExtraVFS for extended VFS usage such as redirecting savegames

EntryPoint.cs

@@ -6,6 +6,7 @@
 using System.Runtime.ExceptionServices;
 using System.Runtime.InteropServices;
 using System.Threading;
+using Andraste.Payload.ExtraVFS;
 using Andraste.Payload.ModManagement;
 using Andraste.Payload.Native;
 using Andraste.Shared.Lifecycle;
@@ -52,13 +53,15 @@ public abstract class EntryPoint : IEntryPoint
         protected readonly Dictionary<string, IFeatureParser> FeatureParser = new Dictionary<string, IFeatureParser>();
         public readonly ManagerContainer Container;
         private readonly ModLoader _modLoader;
+        private readonly ExtraVFSLoader _extraVFSLoader;
 
         protected EntryPoint(RemoteHooking.IContext context)
         {
             GameFolder = Directory.GetCurrentDirectory();
             ModFolder = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
             Container = new ManagerContainer();
             _modLoader = new ModLoader(this);
+            _extraVFSLoader = new ExtraVFSLoader(this);
         }
 
         public virtual void Run(RemoteHooking.IContext context)
@@ -91,7 +94,9 @@ public virtual void Run(RemoteHooking.IContext context)
 
             Logger.Trace("Implementing Mods");
             ImplementMods();
-
+
+            ImplementExtraVFS();
+
             Logger.Trace("Waking up the Application");
             RemoteHooking.WakeUpProcess();
             Logger.Trace("Calling Post-Wakeup");
@@ -189,7 +194,14 @@ protected virtual void LoadFeatureParsers()
             FeatureParser.Add("andraste.builtin.plugin", new PluginFeatureParser());
         }
         #endregion
-
+
+        #region ExtraVFS
+        protected virtual void ImplementExtraVFS()
+        {
+            _extraVFSLoader.LoadExtraVFSFromJson(ModFolder);
+        }
+        #endregion
+
         #region Lifecycle
         /// <summary>
         /// This is called when Andraste has been loaded so far and the user

ExtraVFS/ExtraVFSLoader.cs

@@ -0,0 +1,98 @@
+using Andraste.Payload.VFS;
+using System;
+using System.IO;
+using System.Text.Json;
+using NLog;
+
+namespace Andraste.Payload.ExtraVFS
+{
+    public class ExtraVFSPairs
+    {
+        public ExtraVFSPair[] PathPairs { get; set; }
+    }
+    public class ExtraVFSPair
+    {
+        public string Source { get; set; }
+        public string Dest { get; set; }
+        public bool DestHasToExist { get; set; }
+    }
+    public class ExtraVFSLoader
+    {
+        private EntryPoint _entryPoint;
+        private static readonly Logger Logger = LogManager.GetCurrentClassLogger();
+
+        public ExtraVFSLoader(EntryPoint entryPoint)
+        {
+            _entryPoint = entryPoint;
+        }
+
+        public void LoadExtraVFSFromJson(string modFolder)
+        {
+            var vfs = _entryPoint.Container.GetManager<BasicFileRedirectingManager>();
+            if (vfs != null)
+            {
+                var jsonFile = Path.Combine(modFolder, "extra_vfs.json");
+                if (!File.Exists(jsonFile))
+                {
+                    var empty_template = new ExtraVFSPairs();
+                    empty_template.PathPairs = new ExtraVFSPair[1];
+                    empty_template.PathPairs[0] = new ExtraVFSPair();
+                    empty_template.PathPairs[0].Source = "C:\\Some\\Savegame\\Path";
+                    empty_template.PathPairs[0].Dest = "C:\\Some\\Savegame\\Path";
+                    empty_template.PathPairs[0].DestHasToExist = false;
+                    var empty_template_string = JsonSerializer.SerializeToUtf8Bytes(empty_template, new JsonSerializerOptions { WriteIndented = true});
+                    try
+                    {
+                        File.WriteAllBytes(jsonFile, empty_template_string);
+                    }
+                    catch(Exception ex)
+                    {
+                        Logger.Warn("Couldn't create template extra_vfs.json, " + ex);
+                    }
+                }
+
+                try
+                {
+                    var pairs = JsonSerializer.Deserialize<ExtraVFSPairs>(File.ReadAllText(jsonFile));
+                    if (pairs == null)
+                    {
+                        Logger.Warn("Couldn't properly parse extra_vfs.json");
+                        return;
+                    }
+
+                    if (pairs.PathPairs == null)
+                    {
+                        return;
+                    }
+
+                    foreach (var pair in pairs.PathPairs)
+                    {
+                        if (!Directory.Exists(pair.Dest) && pair.DestHasToExist)
+                        {
+                            try
+                            {
+                                Directory.CreateDirectory(pair.Dest);
+                            }
+                            catch (Exception ex)
+                            {
+                                Logger.Error("Destination " + pair.Dest + " does not exist and cannot be created, " + ex);
+                                throw ex;
+                            }
+                        }
+                        Logger.Trace("adding pair " + pair.Source + ", " + pair.Dest);
+                        vfs.AddPrefixMapping(pair.Source.Replace('/', '\\'), pair.Dest.Replace('/', '\\'));
+                    }
+                }
+                catch(Exception ex)
+                {
+                    Logger.Warn("ExtraVFS: Couldn't properly parse extra_vfs.json, " + ex);
+                }
+                return;
+            }
+            else
+            {
+                Logger.Info($"The Framework {_entryPoint.FrameworkName} has not enabled VFS Features");
+            }
+        }
+    }
+}

Native/Kernel32.cs

@@ -26,7 +26,22 @@ public static extern IntPtr CreateFileA(string lpFileName, uint dwDesiredAccess,
         public delegate IntPtr Delegate_CreateFileA(string lpFileName, uint dwDesiredAccess,
             uint dwShareMode, IntPtr lpSecurityAttributes, uint dwCreationDisposition,
             uint dwFlagsAndAttributes, IntPtr hTemplateFile);
-
+
+        [DllImport("kernel32.dll", CharSet = CharSet.Ansi)]
+        public static extern bool CreateDirectoryA(string lpFileName, IntPtr lpSecurityAttributes);
+
+        public delegate bool Delegate_CreateDirectoryA(string lpFileName, IntPtr lpSecurityAttribute);
+
+        [DllImport("kernel32.dll", CharSet = CharSet.Ansi)]
+        public static extern bool DeleteFileA(string lpFileName);
+
+        public delegate bool Delegate_DeleteFileA(string lpFileName);
+
+        [DllImport("kernel32.dll", CharSet = CharSet.Ansi)]
+        public static extern bool RemoveDirectoryA(string lpFileName);
+
+        public delegate bool Delegate_RemoveDirectoryA(string lpFileName);
+
         [DllImport("kernel32.dll")]
         public static extern bool VirtualProtect(IntPtr lpAddress, IntPtr dwSize, uint flNewProtect, out uint lpflOldProtect);
 

Native/Shell32.cs

@@ -0,0 +1,12 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace Andraste.Payload.Native
+{
+    public static class Shell32
+    {
+        [DllImport("shell32.dll", CharSet = CharSet.Ansi)]
+        public static extern int SHFileOperationA(IntPtr lpFileOp);
+        public delegate int Delegate_SHFileOperationA(IntPtr lpFileOp);
+    }
+}