feat: make Unity integration optional

CodeGen/Editor/EventBusILPostProcessor.cs

@@ -1,7 +1,10 @@
 #nullable enable
-
+using System;
 using System.Collections.Generic;
-using ShrinkShared.CodeGen;
+using System.IO;
+using System.Linq;
+using Mono.Cecil;
+using Mono.Cecil.Cil;
 using Unity.CompilationPipeline.Common.Diagnostics;
 using Unity.CompilationPipeline.Common.ILPostProcessing;
 
@@ -11,12 +14,66 @@ namespace ShrinkEventBus.CodeGen
     {
         public override ILPostProcessor GetInstance() => this;
 
-        // ShrinkRegistryILPostProcessor owns the complete pass, including event bindings.
-        public override bool WillProcess(ICompiledAssembly compiledAssembly) => false;
+        public override bool WillProcess(ICompiledAssembly compiledAssembly)
+        {
+#if SHRINK_EVENTBUS_HAS_SHARED_CODEGEN
+            // The shared processor owns event weaving when its package is installed.
+            return false;
+#else
+            return compiledAssembly.Name != "ShrinkEventBus.Runtime" &&
+                   compiledAssembly.References.Any(path =>
+                       Path.GetFileNameWithoutExtension(path) == "ShrinkEventBus.Runtime");
+#endif
+        }
 
-        public override ILPostProcessResult Process(ICompiledAssembly compiledAssembly) =>
-            WillProcess(compiledAssembly)
-                ? UnityShrinkCodeGenAdapter.Process(compiledAssembly, "ShrinkEventBus.CodeGen")
-                : new ILPostProcessResult(compiledAssembly.InMemoryAssembly, new List<DiagnosticMessage>());
+        public override ILPostProcessResult Process(ICompiledAssembly compiledAssembly)
+        {
+            var diagnostics = new List<DiagnosticMessage>();
+#if !SHRINK_EVENTBUS_HAS_SHARED_CODEGEN
+            if (!WillProcess(compiledAssembly))
+                return new ILPostProcessResult(compiledAssembly.InMemoryAssembly, diagnostics);
+            try
+            {
+                using var resolver = new PostProcessorAssemblyResolver(compiledAssembly);
+                using var pe = new MemoryStream(compiledAssembly.InMemoryAssembly.PeData);
+                var pdbData = compiledAssembly.InMemoryAssembly.PdbData;
+                var hasSymbols = pdbData != null && pdbData.Length > 0;
+                using var pdb = hasSymbols ? new MemoryStream(pdbData!) : null;
+                using var assembly = AssemblyDefinition.ReadAssembly(pe, new ReaderParameters
+                {
+                    AssemblyResolver = resolver,
+                    ReadingMode = ReadingMode.Immediate,
+                    ReflectionImporterProvider = new PostProcessorReflectionImporterProvider(),
+                    ReadSymbols = hasSymbols,
+                    SymbolStream = pdb,
+                    SymbolReaderProvider = hasSymbols ? new PortablePdbReaderProvider() : null
+                });
+                resolver.AddAssemblyDefinitionBeingOperatedOn(assembly);
+                if (assembly.Name.HasPublicKey)
+                    throw new InvalidOperationException("Signed assemblies cannot be woven by the standalone EventBus processor.");
+                if (!EventBusAssemblyWeaver.Weave(assembly.MainModule))
+                    return new ILPostProcessResult(compiledAssembly.InMemoryAssembly, diagnostics);
+                using var outputPe = new MemoryStream();
+                using var outputPdb = new MemoryStream();
+                assembly.Write(outputPe, new WriterParameters
+                {
+                    WriteSymbols = hasSymbols,
+                    SymbolStream = hasSymbols ? outputPdb : null,
+                    SymbolWriterProvider = hasSymbols ? new PortablePdbWriterProvider() : null
+                });
+                return new ILPostProcessResult(new InMemoryAssembly(outputPe.ToArray(),
+                    hasSymbols ? outputPdb.ToArray() : Array.Empty<byte>()), diagnostics);
+            }
+            catch (Exception exception)
+            {
+                diagnostics.Add(new DiagnosticMessage
+                {
+                    DiagnosticType = DiagnosticType.Error,
+                    MessageData = $"[ShrinkEventBus.CodeGen] {exception.Message}"
+                });
+            }
+#endif
+            return new ILPostProcessResult(compiledAssembly.InMemoryAssembly, diagnostics);
+        }
     }
 }