AssemblyResolver.cs

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/*
  Copyright (C) 2010-2013 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.Collections.Generic;
using System.IO;
 
using IKVM.Reflection;
using IKVM.Runtime;
 
namespace IKVM.Tools.Importer
{
 
    sealed class AssemblyResolver
    {
 
        readonly List<string> libpath = new List<string>();
        Universe universe;
        Version coreLibVersion;
 
        internal enum WarningId
        {
            HigherVersion = 1,
            LocationIgnored = 2,
            InvalidLibDirectoryOption = 3,
            InvalidLibDirectoryEnvironment = 4,
            LegacySearchRule = 5,
        }
 
        internal delegate void WarningEvent(WarningId warning, string message, string[] parameters);
        internal event WarningEvent Warning;
 
        private void EmitWarning(WarningId warning, string message, params string[] parameters)
        {
            if (Warning != null)
            {
                Warning(warning, message, parameters);
            }
            else
            {
                Console.Error.WriteLine("Warning: " + message, parameters);
            }
        }
 
        internal void Init(Universe universe, bool nostdlib, IList<string> references, IList<string> userLibPaths)
        {
            this.universe = universe;
 
            // like the C# compiler, the references are loaded from:
            // current directory, CLR directory, -lib: option, %LIB% environment
            // (note that, unlike the C# compiler, we don't add the CLR directory if -nostdlib has been specified)
            libpath.Add(Environment.CurrentDirectory);
 
            if (nostdlib == false)
                libpath.Add(System.Runtime.InteropServices.RuntimeEnvironment.GetRuntimeDirectory());
 
            foreach (var str in userLibPaths)
                AddLibraryPaths(str, true);
 
            AddLibraryPaths(Environment.GetEnvironmentVariable("LIB") ?? "", false);
 
            if (nostdlib)
            {
                coreLibVersion = LoadCoreLib(references).GetName().Version;
            }
            else
            {
                coreLibVersion = universe.Load(universe.CoreLibName).GetName().Version;
            }
 
#if IMPORTER
            universe.AssemblyResolve += AssemblyResolve;
#else
            universe.AssemblyResolve += LegacyAssemblyResolve;
#endif
        }
 
        internal Assembly LoadFile(string path)
        {
            string ex = null;
            try
            {
                using (RawModule module = universe.OpenRawModule(path))
                {
                    if (coreLibVersion != null)
                    {
                        // to avoid problems (i.e. weird exceptions), we don't allow assemblies to load that reference a newer version of mscorlib
                        foreach (AssemblyName asmref in module.GetReferencedAssemblies())
                        {
                            if (asmref.Name == universe.CoreLibName && asmref.Version > coreLibVersion)
                            {
                                Console.Error.WriteLine("Error: unable to load assembly '{0}' as it depends on a higher version of mscorlib than the one currently loaded", path);
                                Environment.Exit(1);
                            }
                        }
                    }
                    Assembly asm = universe.LoadAssembly(module);
                    if (asm.Location != module.Location && CanonicalizePath(asm.Location) != CanonicalizePath(module.Location))
                    {
                        EmitWarning(WarningId.LocationIgnored, "assembly \"{0}\" is ignored as previously loaded assembly \"{1}\" has the same identity \"{2}\"", path, asm.Location, asm.FullName);
                    }
                    return asm;
                }
            }
            catch (IOException x)
            {
                ex = x.Message;
            }
            catch (UnauthorizedAccessException x)
            {
                ex = x.Message;
            }
            catch (IKVM.Reflection.BadImageFormatException x)
            {
                ex = x.Message;
            }
            Console.Error.WriteLine("Error: unable to load assembly '{0}'" + Environment.NewLine + "    ({1})", path, ex);
            Environment.Exit(1);
            return null;
        }
 
        private static string CanonicalizePath(string path)
        {
            try
            {
                System.IO.FileInfo fi = new System.IO.FileInfo(path);
                if (fi.DirectoryName == null)
                {
                    return path.Length > 1 && path[1] == ':' ? path.ToUpper() : path;
                }
                string dir = CanonicalizePath(fi.DirectoryName);
                string name = fi.Name;
                try
                {
                    string[] arr = System.IO.Directory.GetFileSystemEntries(dir, name);
                    if (arr.Length == 1)
                    {
                        name = arr[0];
                    }
                }
                catch (System.UnauthorizedAccessException)
                {
                }
                catch (System.IO.IOException)
                {
                }
                return System.IO.Path.Combine(dir, name);
            }
            catch (System.UnauthorizedAccessException)
            {
            }
            catch (System.IO.IOException)
            {
            }
            catch (System.Security.SecurityException)
            {
            }
            catch (System.NotSupportedException)
            {
            }
            return path;
        }
 
        internal Assembly LoadWithPartialName(string name)
        {
            foreach (string path in FindAssemblyPath(name + ".dll"))
                return LoadFile(path);
 
            return null;
        }
 
        internal bool ResolveReference(Dictionary<string, Assembly> cache, ref Assembly[] references, string reference)
        {
            string[] files = new string[0];
            try
            {
                string path = Path.GetDirectoryName(reference);
                files = Directory.GetFiles(path == "" ? "." : path, Path.GetFileName(reference));
            }
            catch (ArgumentException)
            {
            }
            catch (IOException)
            {
            }
            if (files.Length == 0)
            {
                Assembly asm = null;
                cache.TryGetValue(reference, out asm);
                if (asm == null)
                {
                    foreach (string found in FindAssemblyPath(reference))
                    {
                        asm = LoadFile(found);
                        cache.Add(reference, asm);
                        break;
                    }
                }
                if (asm == null)
                {
                    return false;
                }
                ArrayAppend(ref references, asm);
            }
            else
            {
                foreach (string file in files)
                {
                    Assembly asm;
                    if (!cache.TryGetValue(file, out asm))
                    {
                        asm = LoadFile(file);
                    }
                    ArrayAppend(ref references, asm);
                }
            }
            return true;
        }
 
        private static void ArrayAppend<T>(ref T[] array, T element)
        {
            if (array == null)
            {
                array = new T[] { element };
            }
            else
            {
                array = ArrayUtil.Concat(array, element);
            }
        }
 
        Assembly AssemblyResolve(object sender, IKVM.Reflection.ResolveEventArgs args)
        {
            var name = new AssemblyName(args.Name);
 
            foreach (var asm in universe.GetAssemblies())
                if (Match(asm.GetName(), name))
                    return asm;
 
            if (args.RequestingAssembly != null)
            {
                return universe.CreateMissingAssembly(args.Name);
            }
            else
            {
                return null;
            }
        }
 
        private Assembly LegacyAssemblyResolve(object sender, IKVM.Reflection.ResolveEventArgs args)
        {
            return LegacyLoad(new AssemblyName(args.Name), args.RequestingAssembly);
        }
 
        internal Assembly LegacyLoad(AssemblyName name, Assembly requestingAssembly)
        {
            foreach (Assembly asm in universe.GetAssemblies())
                if (Match(asm.GetName(), name))
                    return asm;
 
            foreach (string file in FindAssemblyPath(name.Name + ".dll"))
                if (Match(AssemblyName.GetAssemblyName(file), name))
                    return LoadFile(file);
 
            if (requestingAssembly != null)
            {
                var path = Path.Combine(Path.GetDirectoryName(requestingAssembly.Location), name.Name + ".dll");
                if (File.Exists(path) && Match(AssemblyName.GetAssemblyName(path), name))
                    return LoadFile(path);
            }
 
#if EXPORTER
            return universe.CreateMissingAssembly(name.FullName);
#else
            Console.Error.WriteLine("Error: unable to find assembly '{0}'", name.FullName);
            if (requestingAssembly != null)
                Console.Error.WriteLine("    (a dependency of '{0}')", requestingAssembly.FullName);
#endif
 
            throw new InvalidOperationException();
        }
 
        private bool Match(AssemblyName assemblyDef, AssemblyName assemblyRef)
        {
            return assemblyRef.Name == assemblyDef.Name;
        }
 
        private void AddLibraryPaths(string str, bool option)
        {
            foreach (string dir in str.Split(Path.PathSeparator))
            {
                if (Directory.Exists(dir))
                {
                    libpath.Add(dir);
                }
                else if (dir != "")
                {
                    if (option)
                    {
                        EmitWarning(WarningId.InvalidLibDirectoryOption, "directory \"{0}\" specified in -lib option is not valid", dir);
                    }
                    else
                    {
                        EmitWarning(WarningId.InvalidLibDirectoryEnvironment, "directory \"{0}\" specified in LIB environment is not valid", dir);
                    }
                }
            }
        }
 
        Assembly LoadCoreLib(IList<string> references)
        {
            if (references != null)
            {
                foreach (var r in references)
                {
                    try
                    {
                        if (AssemblyName.GetAssemblyName(r).Name == universe.CoreLibName)
                        {
                            return LoadFile(r);
                        }
                    }
                    catch
                    {
 
                    }
                }
            }
 
            foreach (var coreLib in FindAssemblyPath(universe.CoreLibName + ".dll"))
                return LoadFile(coreLib);
 
            Console.Error.WriteLine($"Error: unable to find '{universe.CoreLibName}.dll'.");
            Environment.Exit(1);
            return null;
        }
 
        IEnumerable<string> FindAssemblyPath(string file)
        {
            if (Path.IsPathRooted(file))
            {
                if (File.Exists(file))
                {
                    yield return file;
                }
            }
            else
            {
                foreach (string dir in libpath)
                {
                    var path = Path.Combine(dir, file);
                    if (File.Exists(path))
                        yield return path;
 
                    // for legacy compat, we try again after appending .dll
                    path = Path.Combine(dir, file + ".dll");
                    if (File.Exists(path))
                    {
                        EmitWarning(WarningId.LegacySearchRule, "found assembly \"{0}\" using legacy search rule, please append '.dll' to the reference", file);
                        yield return path;
                    }
                }
            }
        }
 
    }
 
}