Resource Proxy

2025-06-27 13:33:13 +00:00 · 2019-07-23 06:22:24 +03:00
parent 2d9f61c0d9
commit a2f4238933
12 changed files with 238 additions and 23 deletions
--- a/Esiur/Proxy/ResourceProxy.cs
+++ b/Esiur/Proxy/ResourceProxy.cs
@ -0,0 +1,151 @@
+using Esiur.Resource;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Reflection.Emit;
+using System.Text;
+
+namespace Esiur.Proxy
+{
+    public static class ResourceProxy
+    {
+        static Dictionary<Type, Type> cache = new Dictionary<Type, Type>();
+
+#if NETSTANDARD1_5
+        static MethodInfo modifyMethod = typeof(Instance).GetTypeInfo().GetMethod("Modified");
+        static MethodInfo instanceGet = typeof(IResource).GetTypeInfo().GetProperty("Instance").GetGetMethod();
+#else
+        static MethodInfo modifyMethod = typeof(Instance).GetMethod("Modified");
+        static MethodInfo instanceGet = typeof(IResource).GetProperty("Instance").GetGetMethod();
+#endif
+
+
+        public static Type GetProxy(Type type)
+        {
+
+            if (cache.ContainsKey(type))
+                return cache[type];
+
+#if NETSTANDARD1_5
+            var typeInfo = type.GetTypeInfo();
+
+            if (typeInfo.IsSealed)
+                throw new Exception("Sealed class can't be proxied.");
+
+            var props = from p in typeInfo.GetProperties()
+                        where p.CanWrite && p.GetSetMethod().IsVirtual &&
+                        p.GetCustomAttributes(typeof(ResourceProperty), false).Count() > 0
+                        select p;
+
+#else
+            if (type.IsSealed)
+                throw new Exception("Sealed class can't be proxied.");
+
+            var props = from p in type.GetProperties()
+                where p.CanWrite && p.GetSetMethod().IsVirtual && 
+                p.GetCustomAttributes(typeof(ResourceProperty), false).Count() > 0
+                select p;
+
+#endif
+            var assemblyName = new AssemblyName("Esiur.Proxy.T." + type.Namespace);
+            var assemblyBuilder = AssemblyBuilder.DefineDynamicAssembly(assemblyName, AssemblyBuilderAccess.Run);
+            var moduleBuilder = assemblyBuilder.DefineDynamicModule(assemblyName.Name);
+            var typeName = Assembly.CreateQualifiedName(assemblyName.FullName, type.Name);
+
+            var typeBuilder = moduleBuilder.DefineType(typeName,
+                TypeAttributes.Public | TypeAttributes.Class, type);
+
+            foreach (PropertyInfo propertyInfo in props)
+                CreateProperty(propertyInfo, typeBuilder);
+
+
+
+#if NETSTANDARD1_5
+            var t = typeBuilder.CreateTypeInfo().AsType();
+            cache.Add(type, t);
+            return t;
+#else
+            
+            var t = typeBuilder.CreateType();
+            cache.Add(type, t);
+            return t;
+#endif
+        }
+
+        public static Type GetProxy<T>()
+            where T : IResource
+        {
+            return GetProxy(typeof(T));
+        }
+
+
+
+        private static void CreateProperty(PropertyInfo pi, TypeBuilder typeBuilder)
+        {
+            var propertyBuilder = typeBuilder.DefineProperty(pi.Name, PropertyAttributes.None, pi.PropertyType, null);
+
+            // Create set method
+            MethodBuilder builder = typeBuilder.DefineMethod("set_" + pi.Name,
+                MethodAttributes.Public | MethodAttributes.Virtual, null, new Type[] { pi.PropertyType });
+            builder.DefineParameter(1, ParameterAttributes.None, "value");
+            ILGenerator g = builder.GetILGenerator();
+
+            Label callModified = g.DefineLabel();
+            Label exitMethod = g.DefineLabel();
+
+            /*
+             IL_0000: ldarg.0
+	            IL_0001: call instance class [Esiur]Esiur.Resource.Instance [Esiur]Esiur.Resource.Resource::get_Instance()
+	            // (no C# code)
+	            IL_0006: dup
+	            IL_0007: brtrue.s IL_000c
+
+	            IL_0009: pop
+	            // }
+	            IL_000a: br.s IL_0017
+
+	            // (no C# code)
+	            IL_000c: ldstr "Level3"
+	            IL_0011: call instance void [Esiur]Esiur.Resource.Instance::Modified(string)
+	            IL_0016: nop
+
+	            IL_0017: ret
+
+             */
+
+            // Add IL code for set method
+            g.Emit(OpCodes.Nop);
+            g.Emit(OpCodes.Ldarg_0);
+            g.Emit(OpCodes.Ldarg_1);
+            g.Emit(OpCodes.Call, pi.GetSetMethod());
+
+            /*
+                IL_0000: ldarg.0
+ 	            IL_0001: call instance class [Esiur]Esiur.Resource.Instance [Esiur]Esiur.Resource.Resource::get_Instance()
+ 	            IL_0006: ldstr "Level3"
+	            IL_000b: callvirt instance void [Esiur]Esiur.Resource.Instance::Modified(string)
+	            IL_0010: ret
+             */
+
+            // Call property changed for object
+            g.Emit(OpCodes.Nop);
+            g.Emit(OpCodes.Ldarg_0);
+            g.Emit(OpCodes.Call, instanceGet);
+
+            g.Emit(OpCodes.Dup);
+            g.Emit(OpCodes.Brtrue_S, callModified);
+            g.Emit(OpCodes.Pop);
+            g.Emit(OpCodes.Br_S, exitMethod);
+
+            g.MarkLabel(callModified);
+            g.Emit(OpCodes.Ldstr, pi.Name);
+            g.Emit(OpCodes.Callvirt, modifyMethod);
+            g.Emit(OpCodes.Nop);
+            g.MarkLabel(exitMethod);
+            g.Emit(OpCodes.Ret);
+            propertyBuilder.SetSetMethod(builder);
+        }
+
+    }
+}