plugin security fixes and other abstractions

MediaBrowser.Server.Implementations/Reflection/TypeMapper.cs

@@ -0,0 +1,47 @@
+using System;
+using System.Collections.Concurrent;
+using System.Linq;
+
+namespace MediaBrowser.Server.Implementations.Reflection
+{
+    /// <summary>
+    /// Class TypeMapper
+    /// </summary>
+    public class TypeMapper
+    {
+        /// <summary>
+        /// This holds all the types in the running assemblies so that we can de-serialize properly when we don't have strong types
+        /// </summary>
+        private readonly ConcurrentDictionary<string, Type> _typeMap = new ConcurrentDictionary<string, Type>();
+
+        /// <summary>
+        /// Gets the type.
+        /// </summary>
+        /// <param name="typeName">Name of the type.</param>
+        /// <returns>Type.</returns>
+        /// <exception cref="System.ArgumentNullException"></exception>
+        public Type GetType(string typeName)
+        {
+            if (string.IsNullOrEmpty(typeName))
+            {
+                throw new ArgumentNullException();
+            }
+
+            return _typeMap.GetOrAdd(typeName, LookupType);
+        }
+
+        /// <summary>
+        /// Lookups the type.
+        /// </summary>
+        /// <param name="typeName">Name of the type.</param>
+        /// <returns>Type.</returns>
+        private Type LookupType(string typeName)
+        {
+            return AppDomain
+                        .CurrentDomain
+                        .GetAssemblies()
+                        .Select(a => a.GetType(typeName, false))
+                        .FirstOrDefault(t => t != null);
+        }
+    }
+}