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Diffstat (limited to 'src/StardewModdingAPI/Framework/AssemblyLoader.cs')
| -rw-r--r-- | src/StardewModdingAPI/Framework/AssemblyLoader.cs | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/src/StardewModdingAPI/Framework/AssemblyLoader.cs b/src/StardewModdingAPI/Framework/AssemblyLoader.cs new file mode 100644 index 00000000..123211b9 --- /dev/null +++ b/src/StardewModdingAPI/Framework/AssemblyLoader.cs @@ -0,0 +1,244 @@ +using System; +using System.Collections.Generic; +using System.IO; +using System.Linq; +using System.Reflection; +using Mono.Cecil; +using Mono.Cecil.Cil; +using Mono.Cecil.Rocks; +using StardewModdingAPI.AssemblyRewriters; + +namespace StardewModdingAPI.Framework +{ + /// <summary>Preprocesses and loads mod assemblies.</summary> + internal class AssemblyLoader + { + /********* + ** Properties + *********/ + /// <summary>Metadata for mapping assemblies to the current platform.</summary> + private readonly PlatformAssemblyMap AssemblyMap; + + /// <summary>A type => assembly lookup for types which should be rewritten.</summary> + private readonly IDictionary<string, Assembly> TypeAssemblies; + + /// <summary>Encapsulates monitoring and logging.</summary> + private readonly IMonitor Monitor; + + + /********* + ** Public methods + *********/ + /// <summary>Construct an instance.</summary> + /// <param name="targetPlatform">The current game platform.</param> + /// <param name="monitor">Encapsulates monitoring and logging.</param> + public AssemblyLoader(Platform targetPlatform, IMonitor monitor) + { + this.Monitor = monitor; + this.AssemblyMap = Constants.GetAssemblyMap(targetPlatform); + + // generate type => assembly lookup for types which should be rewritten + this.TypeAssemblies = new Dictionary<string, Assembly>(); + foreach (Assembly assembly in this.AssemblyMap.Targets) + { + ModuleDefinition module = this.AssemblyMap.TargetModules[assembly]; + foreach (TypeDefinition type in module.GetTypes()) + { + if (!type.IsPublic) + continue; // no need to rewrite + if (type.Namespace.Contains("<")) + continue; // ignore assembly metadata + this.TypeAssemblies[type.FullName] = assembly; + } + } + } + + /// <summary>Preprocess and load an assembly.</summary> + /// <param name="assemblyPath">The assembly file path.</param> + /// <returns>Returns the rewrite metadata for the preprocessed assembly.</returns> + public Assembly Load(string assemblyPath) + { + // get referenced local assemblies + AssemblyParseResult[] assemblies; + { + AssemblyDefinitionResolver resolver = new AssemblyDefinitionResolver(); + assemblies = this.GetReferencedLocalAssemblies(new FileInfo(assemblyPath), new HashSet<string>(), resolver).ToArray(); + if (!assemblies.Any()) + throw new InvalidOperationException($"Could not load '{assemblyPath}' because it doesn't exist."); + resolver.Add(assemblies.Select(p => p.Definition).ToArray()); + } + + // rewrite & load assemblies in leaf-to-root order + Assembly lastAssembly = null; + foreach (AssemblyParseResult assembly in assemblies) + { + this.Monitor.Log($"Loading {assembly.File.Name}...", LogLevel.Trace); + bool changed = this.RewriteAssembly(assembly.Definition); + if (changed) + { + using (MemoryStream outStream = new MemoryStream()) + { + assembly.Definition.Write(outStream); + byte[] bytes = outStream.ToArray(); + lastAssembly = Assembly.Load(bytes); + } + } + else + lastAssembly = Assembly.UnsafeLoadFrom(assembly.File.FullName); + } + + // last assembly loaded is the root + return lastAssembly; + } + + /// <summary>Resolve an assembly by its name.</summary> + /// <param name="name">The assembly name.</param> + /// <remarks> + /// This implementation returns the first loaded assembly which matches the short form of + /// the assembly name, to resolve assembly resolution issues when rewriting + /// assemblies (especially with Mono). Since this is meant to be called on <see cref="AppDomain.AssemblyResolve"/>, + /// the implicit assumption is that loading the exact assembly failed. + /// </remarks> + public Assembly ResolveAssembly(string name) + { + string shortName = name.Split(new[] { ',' }, 2).First(); // get simple name (without version and culture) + return AppDomain.CurrentDomain + .GetAssemblies() + .FirstOrDefault(p => p.GetName().Name == shortName); + } + + + /********* + ** Private methods + *********/ + /**** + ** Assembly parsing + ****/ + /// <summary>Get a list of referenced local assemblies starting from the mod assembly, ordered from leaf to root.</summary> + /// <param name="file">The assembly file to load.</param> + /// <param name="visitedAssemblyPaths">The assembly paths that should be skipped.</param> + /// <returns>Returns the rewrite metadata for the preprocessed assembly.</returns> + private IEnumerable<AssemblyParseResult> GetReferencedLocalAssemblies(FileInfo file, HashSet<string> visitedAssemblyPaths, IAssemblyResolver assemblyResolver) + { + // validate + if (file.Directory == null) + throw new InvalidOperationException($"Could not get directory from file path '{file.FullName}'."); + if (visitedAssemblyPaths.Contains(file.FullName)) + yield break; // already visited + if (!file.Exists) + yield break; // not a local assembly + visitedAssemblyPaths.Add(file.FullName); + + // read assembly + byte[] assemblyBytes = File.ReadAllBytes(file.FullName); + AssemblyDefinition assembly; + using (Stream readStream = new MemoryStream(assemblyBytes)) + assembly = AssemblyDefinition.ReadAssembly(readStream, new ReaderParameters(ReadingMode.Deferred) { AssemblyResolver = assemblyResolver }); + + // yield referenced assemblies + foreach (AssemblyNameReference dependency in assembly.MainModule.AssemblyReferences) + { + FileInfo dependencyFile = new FileInfo(Path.Combine(file.Directory.FullName, $"{dependency.Name}.dll")); + foreach (AssemblyParseResult result in this.GetReferencedLocalAssemblies(dependencyFile, visitedAssemblyPaths, assemblyResolver)) + yield return result; + } + + // yield assembly + yield return new AssemblyParseResult(file, assembly); + } + + /**** + ** Assembly rewriting + ****/ + /// <summary>Rewrite the types referenced by an assembly.</summary> + /// <param name="assembly">The assembly to rewrite.</param> + /// <returns>Returns whether the assembly was modified.</returns> + private bool RewriteAssembly(AssemblyDefinition assembly) + { + ModuleDefinition module = assembly.Modules.Single(); // technically an assembly can have multiple modules, but none of the build tools (including MSBuild) support it; simplify by assuming one module + + // remove old assembly references + bool shouldRewrite = false; + for (int i = 0; i < module.AssemblyReferences.Count; i++) + { + if (this.AssemblyMap.RemoveNames.Any(name => module.AssemblyReferences[i].Name == name)) + { + shouldRewrite = true; + module.AssemblyReferences.RemoveAt(i); + i--; + } + } + if (!shouldRewrite) + return false; + + // add target assembly references + foreach (AssemblyNameReference target in this.AssemblyMap.TargetReferences.Values) + module.AssemblyReferences.Add(target); + + // rewrite type scopes to use target assemblies + IEnumerable<TypeReference> typeReferences = module.GetTypeReferences().OrderBy(p => p.FullName); + foreach (TypeReference type in typeReferences) + this.ChangeTypeScope(type); + + // rewrite incompatible methods + IMethodRewriter[] methodRewriters = Constants.GetMethodRewriters().ToArray(); + foreach (MethodDefinition method in this.GetMethods(module)) + { + // skip methods with no rewritable method + bool hasMethodToRewrite = method.Body.Instructions.Any(op => (op.OpCode == OpCodes.Call || op.OpCode == OpCodes.Callvirt) && methodRewriters.Any(rewriter => rewriter.ShouldRewrite((MethodReference)op.Operand))); + if (!hasMethodToRewrite) + continue; + + // rewrite method references + method.Body.SimplifyMacros(); + ILProcessor cil = method.Body.GetILProcessor(); + Instruction[] instructions = cil.Body.Instructions.ToArray(); + foreach (Instruction op in instructions) + { + if (op.OpCode == OpCodes.Call || op.OpCode == OpCodes.Callvirt) + { + IMethodRewriter rewriter = methodRewriters.FirstOrDefault(p => p.ShouldRewrite((MethodReference)op.Operand)); + if (rewriter != null) + { + MethodReference methodRef = (MethodReference)op.Operand; + rewriter.Rewrite(module, cil, op, methodRef, this.AssemblyMap); + } + } + } + method.Body.OptimizeMacros(); + } + return true; + } + + /// <summary>Get the correct reference to use for compatibility with the current platform.</summary> + /// <param name="type">The type reference to rewrite.</param> + private void ChangeTypeScope(TypeReference type) + { + // check skip conditions + if (type == null || type.FullName.StartsWith("System.")) + return; + + // get assembly + Assembly assembly; + if (!this.TypeAssemblies.TryGetValue(type.FullName, out assembly)) + return; + + // replace scope + AssemblyNameReference assemblyRef = this.AssemblyMap.TargetReferences[assembly]; + type.Scope = assemblyRef; + } + + /// <summary>Get all methods in a module.</summary> + /// <param name="module">The module to search.</param> + private IEnumerable<MethodDefinition> GetMethods(ModuleDefinition module) + { + return ( + from type in module.GetTypes() + where type.HasMethods + from method in type.Methods + where method.HasBody + select method + ); + } + } +} |