From 2d06095447b972c8c7239277428e2c67c8b7ca86 Mon Sep 17 00:00:00 2001
From: LukePulverenti <luke.pulverenti@gmail.com>
Date: Mon, 25 Feb 2013 22:43:04 -0500
Subject: plugin security fixes and other abstractions

---
 .../BaseApplicationHost.cs                         | 295 +++++++++++++++++++++
 1 file changed, 295 insertions(+)
 create mode 100644 MediaBrowser.Common.Implementations/BaseApplicationHost.cs

(limited to 'MediaBrowser.Common.Implementations/BaseApplicationHost.cs')

diff --git a/MediaBrowser.Common.Implementations/BaseApplicationHost.cs b/MediaBrowser.Common.Implementations/BaseApplicationHost.cs
new file mode 100644
index 0000000000..c5af5059f3
--- /dev/null
+++ b/MediaBrowser.Common.Implementations/BaseApplicationHost.cs
@@ -0,0 +1,295 @@
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using MediaBrowser.Model.Logging;
+using MediaBrowser.Model.Serialization;
+using SimpleInjector;
+using System;
+using System.Collections.Generic;
+using System.Threading;
+
+namespace MediaBrowser.Common.Implementations
+{
+    public abstract class BaseApplicationHost : IDisposable
+    {
+        /// <summary>
+        /// Gets or sets the logger.
+        /// </summary>
+        /// <value>The logger.</value>
+        public ILogger Logger { get; protected set; }
+
+        /// <summary>
+        /// The container
+        /// </summary>
+        protected readonly Container Container = new Container();
+      
+        /// <summary>
+        /// Gets assemblies that failed to load
+        /// </summary>
+        public List<string> FailedAssemblies { get; protected set; }
+
+        /// <summary>
+        /// Gets all types within all running assemblies
+        /// </summary>
+        /// <value>All types.</value>
+        public Type[] AllTypes { get; protected set; }
+
+        /// <summary>
+        /// Gets all concrete types.
+        /// </summary>
+        /// <value>All concrete types.</value>
+        public Type[] AllConcreteTypes { get; protected set; }
+
+        /// <summary>
+        /// The disposable parts
+        /// </summary>
+        protected readonly List<IDisposable> DisposableParts = new List<IDisposable>();
+
+        /// <summary>
+        /// The _protobuf serializer initialized
+        /// </summary>
+        private bool _protobufSerializerInitialized;
+        /// <summary>
+        /// The _protobuf serializer sync lock
+        /// </summary>
+        private object _protobufSerializerSyncLock = new object();
+        /// <summary>
+        /// Gets a dynamically compiled generated serializer that can serialize protocontracts without reflection
+        /// </summary>
+        private IProtobufSerializer _protobufSerializer;
+        /// <summary>
+        /// Gets the protobuf serializer.
+        /// </summary>
+        /// <value>The protobuf serializer.</value>
+        protected IProtobufSerializer ProtobufSerializer
+        {
+            get
+            {
+                // Lazy load
+                LazyInitializer.EnsureInitialized(ref _protobufSerializer, ref _protobufSerializerInitialized, ref _protobufSerializerSyncLock, () => Serialization.ProtobufSerializer.Create(AllTypes));
+                return _protobufSerializer;
+            }
+            private set
+            {
+                _protobufSerializer = value;
+                _protobufSerializerInitialized = value != null;
+            }
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="BaseApplicationHost" /> class.
+        /// </summary>
+        protected BaseApplicationHost()
+        {
+            FailedAssemblies = new List<string>();
+        }
+
+        /// <summary>
+        /// Gets the composable part assemblies.
+        /// </summary>
+        /// <returns>IEnumerable{Assembly}.</returns>
+        protected abstract IEnumerable<Assembly> GetComposablePartAssemblies();
+
+        /// <summary>
+        /// Discovers the types.
+        /// </summary>
+        protected void DiscoverTypes()
+        {
+            FailedAssemblies.Clear();
+
+            AllTypes = GetComposablePartAssemblies().SelectMany(GetTypes).ToArray();
+
+            AllConcreteTypes = AllTypes.Where(t => t.IsClass && !t.IsAbstract && !t.IsInterface && !t.IsGenericType).ToArray();
+        }
+
+        /// <summary>
+        /// Gets a list of types within an assembly
+        /// This will handle situations that would normally throw an exception - such as a type within the assembly that depends on some other non-existant reference
+        /// </summary>
+        /// <param name="assembly">The assembly.</param>
+        /// <returns>IEnumerable{Type}.</returns>
+        /// <exception cref="System.ArgumentNullException">assembly</exception>
+        protected IEnumerable<Type> GetTypes(Assembly assembly)
+        {
+            if (assembly == null)
+            {
+                throw new ArgumentNullException("assembly");
+            }
+
+            try
+            {
+                return assembly.GetTypes();
+            }
+            catch (ReflectionTypeLoadException ex)
+            {
+                // If it fails we can still get a list of the Types it was able to resolve
+                return ex.Types.Where(t => t != null);
+            }
+        }
+
+        /// <summary>
+        /// Creates an instance of type and resolves all constructor dependancies
+        /// </summary>
+        /// <param name="type">The type.</param>
+        /// <returns>System.Object.</returns>
+        public object CreateInstance(Type type)
+        {
+            try
+            {
+                return Container.GetInstance(type);
+            }
+            catch
+            {
+                Logger.Error("Error creating {0}", type.Name);
+
+                throw;
+            }
+        }
+
+        /// <summary>
+        /// Registers the specified obj.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="obj">The obj.</param>
+        protected void RegisterSingleInstance<T>(T obj)
+            where T : class
+        {
+            Container.RegisterSingle(obj);
+        }
+
+        /// <summary>
+        /// Registers the specified func.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="func">The func.</param>
+        protected void Register<T>(Func<T> func)
+            where T : class
+        {
+            Container.Register(func);
+        }
+
+        /// <summary>
+        /// Registers the single instance.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="func">The func.</param>
+        protected void RegisterSingleInstance<T>(Func<T> func)
+            where T : class
+        {
+            Container.RegisterSingle(func);
+        }
+
+        /// <summary>
+        /// Resolves this instance.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <returns>``0.</returns>
+        public T Resolve<T>()
+        {
+            return (T)Container.GetRegistration(typeof(T), true).GetInstance();
+        }
+
+        /// <summary>
+        /// Resolves this instance.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <returns>``0.</returns>
+        public T TryResolve<T>()
+        {
+            var result = Container.GetRegistration(typeof(T), false);
+
+            if (result == null)
+            {
+                return default(T);
+            }
+            return (T)result.GetInstance();
+        }
+
+        /// <summary>
+        /// Registers the specified service type.
+        /// </summary>
+        /// <param name="serviceType">Type of the service.</param>
+        /// <param name="implementation">Type of the concrete.</param>
+        protected void Register(Type serviceType, Type implementation)
+        {
+            Container.Register(serviceType, implementation);
+        }
+
+        /// <summary>
+        /// Loads the assembly.
+        /// </summary>
+        /// <param name="file">The file.</param>
+        /// <returns>Assembly.</returns>
+        protected Assembly LoadAssembly(string file)
+        {
+            try
+            {
+                return Assembly.Load(File.ReadAllBytes((file)));
+            }
+            catch (Exception ex)
+            {
+                FailedAssemblies.Add(file);
+                Logger.ErrorException("Error loading assembly {0}", ex, file);
+                return null;
+            }
+        }
+
+        /// <summary>
+        /// Gets the exports.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="manageLiftime">if set to <c>true</c> [manage liftime].</param>
+        /// <returns>IEnumerable{``0}.</returns>
+        public IEnumerable<T> GetExports<T>(bool manageLiftime = true)
+        {
+            var currentType = typeof(T);
+
+            Logger.Info("Composing instances of " + currentType.Name);
+
+            var parts = AllConcreteTypes.Where(currentType.IsAssignableFrom).Select(CreateInstance).Cast<T>().ToArray();
+
+            if (manageLiftime)
+            {
+                DisposableParts.AddRange(parts.OfType<IDisposable>());
+            }
+
+            return parts;
+        }
+
+        /// <summary>
+        /// Gets the current application version
+        /// </summary>
+        /// <value>The application version.</value>
+        public Version ApplicationVersion
+        {
+            get
+            {
+                return GetType().Assembly.GetName().Version;
+            }
+        }
+
+        /// <summary>
+        /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
+        /// </summary>
+        public void Dispose()
+        {
+            Dispose(true);
+        }
+
+        /// <summary>
+        /// Releases unmanaged and - optionally - managed resources.
+        /// </summary>
+        /// <param name="dispose"><c>true</c> to release both managed and unmanaged resources; <c>false</c> to release only unmanaged resources.</param>
+        protected virtual void Dispose(bool dispose)
+        {
+            foreach (var part in DisposableParts)
+            {
+                part.Dispose();
+            }
+
+            var b = Container.GetCurrentRegistrations();
+
+            DisposableParts.Clear();
+        }
+    }
+}
-- 
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