ikvm-fork/runtime/DynamicClassLoader.cs

/*
  Copyright (C) 2002, 2003, 2004, 2005, 2006 Jeroen Frijters

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.

  Jeroen Frijters
  jeroen@frijters.net
  
*/
#if !COMPACT_FRAMEWORK
using System;
using System.Collections;
using System.Diagnostics;
using System.Reflection;
using System.Reflection.Emit;

namespace IKVM.Internal
{
	[Flags]
	enum CodeGenOptions
	{
		None = 0,
		Debug = 1,
		NoStackTraceInfo = 2,
		StrictFinalFieldSemantics = 4,
		NoJNI = 8,
	}

	class DynamicClassLoader : TypeWrapperFactory
	{
#if !WHIDBEY
		internal static bool arrayConstructionHack;
		internal static readonly object arrayConstructionLock = new object();
#endif // !WHIDBEY
		private static readonly Hashtable dynamicTypes = Hashtable.Synchronized(new Hashtable());
		private static readonly char[] specialCharacters = { '\\', '+', ',', '[', ']', '*', '&', '\u0000' };
		private static readonly string specialCharactersString = new String(specialCharacters);
		// FXBUG moduleBuilder is static, because multiple dynamic assemblies is broken (TypeResolve doesn't fire)
		// so for the time being, we share one dynamic assembly among all classloaders
		private static ModuleBuilder moduleBuilder;
		private static bool saveDebugImage;
		private static ArrayList saveDebugAssemblies;
		private static int instanceCounter = 0;
		private int instanceId = System.Threading.Interlocked.Increment(ref instanceCounter);
		private ClassLoaderWrapper classLoader;
		private CodeGenOptions codegenoptions;

		static DynamicClassLoader()
		{
			// TODO AppDomain.TypeResolve requires ControlAppDomain permission, but if we don't have that,
			// we should handle that by disabling dynamic class loading
			AppDomain.CurrentDomain.TypeResolve += new ResolveEventHandler(OnTypeResolve);

			// Ref.Emit doesn't like the "<Module>" name for types
			// (since it already defines a pseudo-type named <Module> for global methods and fields)
			dynamicTypes.Add("<Module>", null);
		}

		internal DynamicClassLoader(ClassLoaderWrapper classLoader, CodeGenOptions codegenoptions)
		{
			this.classLoader = classLoader;
			this.codegenoptions = codegenoptions;
		}

		private static Assembly OnTypeResolve(object sender, ResolveEventArgs args)
		{
#if !WHIDBEY
			lock(arrayConstructionLock)
			{
				Tracer.Info(Tracer.ClassLoading, "OnTypeResolve: {0} (arrayConstructionHack = {1})", args.Name, arrayConstructionHack);
				if(arrayConstructionHack)
				{
					return null;
				}
			}
#endif // !WHIDBEY
			TypeWrapper type = (TypeWrapper)dynamicTypes[args.Name];
			if(type == null)
			{
				return null;
			}
			// During static compilation, a TypeResolve event should never trigger a finish.
#if STATIC_COMPILER
			JVM.CriticalFailure("Finish triggered during static compilation. Type = " + args.Name, null);
#else // STATIC_COMPILER
			try
			{
				type.Finish();
			}
			catch(RetargetableJavaException x)
			{
				throw x.ToJava();
			}
#endif // STATIC_COMPILER
			// NOTE We used to remove the type from the hashtable here, but that creates a race condition if
			// another thread also fires the OnTypeResolve event while we're baking the type.
			// I really would like to remove the type from the hashtable, but at the moment I don't see
			// any way of doing that that wouldn't cause this race condition.
			// UPDATE since we now also use the dynamicTypes hashtable to keep track of type names that
			// have been used already, we cannot remove the keys.
			return type.TypeAsTBD.Assembly;
		}

		internal static string EscapeName(string name)
		{
			// TODO the escaping of special characters is not required on .NET 2.0
			// (but it doesn't really hurt that much either, the only overhead is the
			// extra InnerClassAttribute to record the real name of the class)
			// Note that even though .NET 2.0 automatically escapes the special characters,
			// the name that gets passed in ResolveEventArgs.Name of the TypeResolve event
			// contains the unescaped type name.
			if(name.IndexOfAny(specialCharacters) >= 0)
			{
				System.Text.StringBuilder sb = new System.Text.StringBuilder();
				foreach(char c in name)
				{
					if(specialCharactersString.IndexOf(c) >= 0)
					{
						if(c == 0)
						{
							// we can't escape the NUL character, so we replace it with a space.
							sb.Append(' ');
							continue;
						}
						sb.Append('\\');
					}
					sb.Append(c);
				}
				name = sb.ToString();
			}
			return name;
		}

		internal override string AllocMangledName(string mangledTypeName)
		{
			lock(dynamicTypes.SyncRoot)
			{
				mangledTypeName = EscapeName(mangledTypeName);
				// FXBUG the CLR (both 1.1 and 2.0) doesn't like type names that end with a single period,
				// it loses the trailing period in the name that gets passed in the TypeResolve event.
				if(dynamicTypes.ContainsKey(mangledTypeName) || mangledTypeName.EndsWith("."))
				{
#if STATIC_COMPILER
					Tracer.Warning(Tracer.Compiler, "Class name clash: {0}", mangledTypeName);
#endif
					// Java class names cannot contain slashes (since they are converted into periods),
					// so we take advantage of that fact to create a unique name.
					mangledTypeName += "/" + instanceId;
				}
				dynamicTypes.Add(mangledTypeName, null);
			}
			return mangledTypeName;
		}

		internal override TypeWrapper DefineClassImpl(Hashtable types, ClassFile f, object protectionDomain)
		{
			DynamicTypeWrapper type = CreateDynamicTypeWrapper(f);
			// this step can throw a retargettable exception, if the class is incorrect
			bool hasclinit;
			type.CreateStep1(out hasclinit);
			// now we can allocate the mangledTypeName, because the next step cannot fail
			string mangledTypeName = AllocMangledName(f.Name);
			// This step actually creates the TypeBuilder. It is not allowed to throw any exceptions,
			// if an exception does occur, it is due to a programming error in the IKVM or CLR runtime
			// and will cause a CriticalFailure and exit the process.
			type.CreateStep2NoFail(hasclinit, mangledTypeName);
			lock(types.SyncRoot)
			{
				// in very extreme conditions another thread may have beaten us to it
				// and loaded (not defined) a class with the same name, in that case
				// we'll leak the the Reflection.Emit defined type. Also see the comment
				// in ClassLoaderWrapper.RegisterInitiatingLoader().
				TypeWrapper race = (TypeWrapper)types[f.Name];
				if(race == null)
				{
					Debug.Assert(dynamicTypes.ContainsKey(mangledTypeName) && dynamicTypes[mangledTypeName] == null);
					dynamicTypes[mangledTypeName] = type;
					types[f.Name] = type;
#if !STATIC_COMPILER
					type.SetClassObject(JVM.Library.newClass(type, protectionDomain, null));
#endif
				}
				else
				{
					throw new LinkageError("duplicate class definition: " + f.Name);
				}
			}
			return type;
		}

		protected virtual DynamicTypeWrapper CreateDynamicTypeWrapper(ClassFile f)
		{
			return new DynamicTypeWrapper(f, classLoader);
		}

		internal static void PrepareForSaveDebugImage()
		{
			Debug.Assert(moduleBuilder == null);
			saveDebugImage = true;
		}

		internal static bool IsSaveDebugImage
		{
			get
			{
				return saveDebugImage;
			}
		}

		internal override bool EmitDebugInfo
		{
			get
			{
				return (codegenoptions & CodeGenOptions.Debug) != 0;
			}
		}

		internal override bool EmitStackTraceInfo
		{
			get
			{
				// NOTE we're negating the flag here!
				return (codegenoptions & CodeGenOptions.NoStackTraceInfo) == 0;
			}
		}

		internal override bool StrictFinalFieldSemantics
		{
			get
			{
				return (codegenoptions & CodeGenOptions.StrictFinalFieldSemantics) != 0;
			}
		}

		internal override bool NoJNI
		{
			get
			{
				return (codegenoptions & CodeGenOptions.NoJNI) != 0;
			}
		}

		internal static void FinishAll(bool forDebug)
		{
#if !STATIC_COMPILER
			JVM.FinishingForDebugSave = forDebug;
#endif // !STATIC_COMPILER
			Hashtable done = new Hashtable();
			bool more = true;
			while(more)
			{
				more = false;
				ArrayList l = new ArrayList(dynamicTypes.Values);
				foreach(TypeWrapper tw in l)
				{
					if(tw != null && !done.ContainsKey(tw))
					{
						more = true;
						done.Add(tw, tw);
						Tracer.Info(Tracer.Runtime, "Finishing {0}", tw.TypeAsTBD.FullName);
						tw.Finish();
					}
				}
			}
		}

#if !STATIC_COMPILER
		internal static void SaveDebugImage(object mainClass)
		{
			FinishAll(true);
			TypeWrapper mainTypeWrapper = TypeWrapper.FromClass(mainClass);
			mainTypeWrapper.Finish();
			Type mainType = mainTypeWrapper.TypeAsTBD;
			MethodInfo main = mainType.GetMethod("main", BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic, null, new Type[] { typeof(string[]) }, null);
			AssemblyBuilder asm = ((AssemblyBuilder)moduleBuilder.Assembly);
			asm.SetEntryPoint(main, PEFileKinds.ConsoleApplication);
			asm.Save("ikvmdump.exe");
			if(saveDebugAssemblies != null)
			{
				foreach(AssemblyBuilder ab in saveDebugAssemblies)
				{
					ab.Save(ab.GetName().Name + ".dll");
				}
			}
		}
#endif

		internal static void RegisterForSaveDebug(AssemblyBuilder ab)
		{
			if(saveDebugAssemblies == null)
			{
				saveDebugAssemblies = new ArrayList();
			}
			saveDebugAssemblies.Add(ab);
		}

		internal override ModuleBuilder ModuleBuilder
		{
			get
			{
				lock(typeof(DynamicClassLoader))
				{
					if(moduleBuilder == null)
					{
						moduleBuilder = CreateModuleBuilder();
					}
					return moduleBuilder;
				}
			}
		}

		protected virtual ModuleBuilder CreateModuleBuilder()
		{
#if STATIC_COMPILER
			throw new InvalidOperationException();
#else // STATIC_COMPILER
			AssemblyName name = new AssemblyName();
			if(saveDebugImage)
			{
				name.Name = "ikvmdump";
			}
			else
			{
				name.Name = "ikvm_dynamic_assembly__" + instanceId + "__" + (uint)Environment.TickCount;
			}
			DateTime now = DateTime.Now;
			name.Version = new Version(now.Year, (now.Month * 100) + now.Day, (now.Hour * 100) + now.Minute, (now.Second * 1000) + now.Millisecond);
			AssemblyBuilder assemblyBuilder = AppDomain.CurrentDomain.DefineDynamicAssembly(name, saveDebugImage ? AssemblyBuilderAccess.RunAndSave : AssemblyBuilderAccess.Run, null, null, null, null, null, true);
			CustomAttributeBuilder debugAttr = new CustomAttributeBuilder(typeof(DebuggableAttribute).GetConstructor(new Type[] { typeof(bool), typeof(bool) }), new object[] { true, this.EmitDebugInfo });
			assemblyBuilder.SetCustomAttribute(debugAttr);
			return saveDebugImage ? assemblyBuilder.DefineDynamicModule("ikvmdump.exe", "ikvmdump.exe", this.EmitDebugInfo) : assemblyBuilder.DefineDynamicModule(name.Name, this.EmitDebugInfo);
#endif // STATIC_COMPILER
		}
	}
}
#endif //COMPACT_FRAMEWORK