Scripting?

Core/Scripting/ScriptingEngine.cs

@@ -0,0 +1,154 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.IO;
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using RageCoop.Core.Logging;
+using System.Linq;
+
+[assembly: InternalsVisibleTo("RageCoop.Server")]
+[assembly: InternalsVisibleTo("RageCoop.Client")]
+namespace RageCoop.Core.Scripting
+{
+    internal class ScriptingEngine
+    {
+		private Type BaseScriptType;
+		public Logger Logger { get; set; }
+        public ScriptingEngine(Type baseScriptType,Logger logger)
+        {
+			BaseScriptType = baseScriptType;
+			Logger = logger;
+        }
+		/// <summary>
+		/// Loads scripts from the specified assembly file.
+		/// </summary>
+		/// <param name="filename">The path to the assembly file to load.</param>
+		/// <returns><see langword="true" /> on success, <see langword="false" /> otherwise</returns>
+		private bool LoadScriptsFromAssembly(string filename)
+		{
+			if (!IsManagedAssembly(filename))
+				return false;
+
+			Logger?.Debug($"Loading assembly {Path.GetFileName(filename)} ...");
+
+			Assembly assembly;
+
+			try
+			{
+				assembly = Assembly.LoadFrom(filename);
+			}
+			catch (Exception ex)
+			{
+				Logger?.Error( "Unable to load "+Path.GetFileName(filename));
+				Logger?.Error(ex);
+				return false;
+			}
+
+			return LoadScriptsFromAssembly(assembly, filename);
+		}
+		/// <summary>
+		/// Loads scripts from the specified assembly object.
+		/// </summary>
+		/// <param name="filename">The path to the file associated with this assembly.</param>
+		/// <param name="assembly">The assembly to load.</param>
+		/// <returns><see langword="true" /> on success, <see langword="false" /> otherwise</returns>
+		private bool LoadScriptsFromAssembly(Assembly assembly, string filename)
+		{
+			int count = 0;
+
+			try
+			{
+				// Find all script types in the assembly
+				foreach (var type in assembly.GetTypes().Where(x => IsSubclassOf(x,nameof(BaseScriptType))))
+				{
+					ConstructorInfo constructor = type.GetConstructor(System.Type.EmptyTypes);
+					if (constructor != null && constructor.IsPublic)
+					{
+						try
+						{
+							// Invoke script constructor
+							constructor.Invoke(null);
+							count++;
+						}
+						catch (Exception ex)
+						{
+							Logger?.Error($"Error occurred when loading script: {type.FullName}.");
+							Logger?.Error(ex);
+						}
+					}
+					else
+					{
+						Logger?.Error($"Script {type.FullName} has an invalid contructor.");
+					}
+				}
+			}
+			catch (ReflectionTypeLoadException ex)
+			{
+				Logger?.Error($"Failed to load assembly {Path.GetFileName(filename)}: ");
+				Logger?.Error(ex);
+
+				return false;
+			}
+
+			Logger?.Info($"Loaded {count.ToString()} script(s) in {Path.GetFileName(filename)}");
+			return count != 0;
+		}
+		private bool IsManagedAssembly(string filename)
+		{
+			try
+			{
+				using (Stream file = new FileStream(filename, FileMode.Open, FileAccess.Read))
+				{
+					if (file.Length < 64)
+						return false;
+
+					using (BinaryReader bin = new BinaryReader(file))
+					{
+						// PE header starts at offset 0x3C (60). Its a 4 byte header.
+						file.Position = 0x3C;
+						uint offset = bin.ReadUInt32();
+						if (offset == 0)
+							offset = 0x80;
+
+						// Ensure there is at least enough room for the following structures:
+						//     24 byte PE Signature & Header
+						//     28 byte Standard Fields         (24 bytes for PE32+)
+						//     68 byte NT Fields               (88 bytes for PE32+)
+						// >= 128 byte Data Dictionary Table
+						if (offset > file.Length - 256)
+							return false;
+
+						// Check the PE signature. Should equal 'PE\0\0'.
+						file.Position = offset;
+						if (bin.ReadUInt32() != 0x00004550)
+							return false;
+
+						// Read PE magic number from Standard Fields to determine format.
+						file.Position += 20;
+						var peFormat = bin.ReadUInt16();
+						if (peFormat != 0x10b /* PE32 */ && peFormat != 0x20b /* PE32Plus */)
+							return false;
+
+						// Read the 15th Data Dictionary RVA field which contains the CLI header RVA.
+						// When this is non-zero then the file contains CLI data otherwise not.
+						file.Position = offset + (peFormat == 0x10b ? 232 : 248);
+						return bin.ReadUInt32() != 0;
+					}
+				}
+			}
+			catch
+			{
+				// This is likely not a valid assembly if any IO exceptions occur during reading
+				return false;
+			}
+		}
+		private bool IsSubclassOf(Type type, string baseTypeName)
+		{
+			for (Type t = type.BaseType; t != null; t = t.BaseType)
+				if (t.FullName == baseTypeName)
+					return true;
+			return false;
+		}
+	}
+}