DynamicClassLoaderFactory.cs

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/*
  Copyright (C) 2002-2014 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
  
*/
using System;
using System.Runtime.CompilerServices;
using System.Collections.Concurrent;
 
 
#if IMPORTER
using IKVM.Reflection;
using IKVM.Reflection.Emit;
using IKVM.Tools.Importer;
 
using Type = IKVM.Reflection.Type;
using ProtectionDomain = System.Object;
#else
using System.Reflection;
#endif
 
namespace IKVM.Runtime
{
    class DynamicClassLoaderFactory
    {
 
        readonly RuntimeContext context;
        internal readonly ConcurrentDictionary<string, RuntimeJavaType> dynamicTypes = new();
        DynamicClassLoader instance;
 
        public DynamicClassLoaderFactory(RuntimeContext context)
        {
            this.context = context ?? throw new ArgumentNullException(nameof(context));
 
#if IMPORTER == false
            // we attach to the AppDomain.TypeResolve event to be notified when the CLR cannot find a type, and we must provide it
            AppDomain.CurrentDomain.TypeResolve += new ResolveEventHandler(OnTypeResolve);
 
            // exclude '<Module>' as a valid type name, as it overlaps with the pseudo-type for global fields and methods
            dynamicTypes.TryAdd("<Module>", null);
#endif
        }
 
#if IMPORTER == false
 
        Assembly OnTypeResolve(object sender, ResolveEventArgs args)
        {
            return Resolve(dynamicTypes, args.Name);
        }
 
        Assembly Resolve(ConcurrentDictionary<string, RuntimeJavaType> dict, string name)
        {
            if (dict.TryGetValue(name, out var type))
            {
                try
                {
                    type.Finish();
                    return type.TypeAsTBD.Assembly;
                }
                catch (RetargetableJavaException e)
                {
                    throw e.ToJava();
                }
            }
 
            return null;
        }
 
#endif
 
        [System.Security.SecuritySafeCritical]
        public DynamicClassLoader GetOrCreate(RuntimeClassLoader loader)
        {
#if IMPORTER
            // importer uses only one class loader, and we can just return a single dynamic class loader
            return new DynamicClassLoader(context, loader.Diagnostics, ((ImportClassLoader)loader).CreateModuleBuilder(), false);
#else
            // each assembly class loader gets its own dynamic class loader
            if (loader is RuntimeAssemblyClassLoader acl)
            {
                var name = acl.MainAssembly.GetName().Name + context.Options.DynamicAssemblySuffixAndPublicKey;
                foreach (var attr in acl.MainAssembly.GetCustomAttributes<InternalsVisibleToAttribute>())
                {
                    if (attr.AssemblyName == name)
                    {
                        var n = new AssemblyName(name);
#if NETFRAMEWORK
                        n.KeyPair = DynamicClassLoader.ForgedKeyPair.Instance;
#endif
                        return new DynamicClassLoader(context, loader.Diagnostics, DynamicClassLoader.CreateModuleBuilder(context, n), true);
                    }
                }
            }
 
            return instance ??= new DynamicClassLoader(context, loader.Diagnostics, DynamicClassLoader.CreateModuleBuilder(context), false);
#endif
        }
 
        public bool ReserveName(string name)
        {
            return dynamicTypes.TryAdd(name, null);
        }
 
        public static string TypeNameMangleImpl(ConcurrentDictionary<string, RuntimeJavaType> dict, string name, RuntimeJavaType javaType)
        {
            // the CLR maximum type name length is 1023 characters, but we need to leave some room for the suffix that we may need to append to make the name unique
            const int MaxLength = 1000;
 
            if (name.Length > MaxLength)
                name = name.Substring(0, MaxLength) + "/truncated";
 
            var mangledTypeName = TypeNameUtil.ReplaceIllegalCharacters(name);
            var baseTypeName = mangledTypeName;
            int instanceId = 0;
 
            // advance through unique type names until we find a free one
            while (dict.TryAdd(mangledTypeName, javaType) == false)
            {
                javaType.ClassLoader.Diagnostics.GenericCompilerWarning($"Class name clash: {mangledTypeName}");
                mangledTypeName = baseTypeName + "/" + (++instanceId);
            }
 
            return mangledTypeName;
        }
 
    }
 
}