C# CilWorker.Emit方法代码示例

        public void Emit(CilWorker IL)
        {
            var module = IL.GetModule();
            var modifiableType = module.ImportType<IModifiableType>();
            var getInterceptionDisabledMethod = module.ImportMethod<IModifiableType>("get_IsInterceptionDisabled");
            if (!_hostMethod.HasThis)
            {
                IL.Emit(OpCodes.Ldc_I4_0);
                IL.Emit(OpCodes.Stloc, _interceptionDisabled);
                return;
            }

            var skipLabel = IL.Create(OpCodes.Nop);

            // var interceptionDisabled = this.IsInterceptionDisabled;
            IL.Emit(OpCodes.Ldarg_0);
            IL.Emit(OpCodes.Isinst, modifiableType);
            IL.Emit(OpCodes.Brfalse, skipLabel);

            IL.Emit(OpCodes.Ldarg_0);
            IL.Emit(OpCodes.Isinst, modifiableType);
            IL.Emit(OpCodes.Callvirt, getInterceptionDisabledMethod);
            IL.Emit(OpCodes.Stloc, _interceptionDisabled);

            IL.Append(skipLabel);
        }

        /// <summary>
        /// Emits the instructions that obtain the <see cref="IAroundInvoke"/> instance.
        /// </summary>
        /// <param name="IL">The <see cref="CilWorker"/> that points to the current method body.</param>
        public void Emit(CilWorker IL)
        {
            var method = IL.GetMethod();
            var declaringType = method.DeclaringType;
            var module = declaringType.Module;

            var getSurroundingImplementation = module.Import(_getSurroundingImplementationMethod);
            IL.Emit(OpCodes.Ldloc, _invocationInfo);
            IL.Emit(OpCodes.Call, getSurroundingImplementation);
            IL.Emit(OpCodes.Stloc, _surroundingClassImplementation);
        }

        /// <summary>
        /// Emits the instructions that obtain the <see cref="IAroundInvoke"/> instance.
        /// </summary>
        /// <param name="IL">The <see cref="CilWorker"/> that points to the current method body.</param>
        public void Emit(CilWorker IL)
        {
            MethodDefinition method = IL.GetMethod();
            TypeDefinition declaringType = method.DeclaringType;
            ModuleDefinition module = declaringType.Module;

            MethodReference getSurroundingImplementation = module.Import(_getSurroundingImplementationMethod);
            IL.Emit(OpCodes.Ldloc, _invocationInfo);
            IL.Emit(OpCodes.Call, getSurroundingImplementation);
            IL.Emit(OpCodes.Stloc, _surroundingClassImplementation);
        }

        public void EmitNewObject(MethodDefinition hostMethod, CilWorker IL, MethodReference targetConstructor,
                                  TypeReference concreteType)
        {
            ParameterDefinitionCollection parameters = targetConstructor.Parameters;
            Instruction skipInterception = IL.Create(OpCodes.Nop);

            SaveConstructorArguments(IL, parameters);
            EmitCreateMethodActivationContext(hostMethod, IL, concreteType);

            // Skip the interception if an activator cannot be found
            EmitGetActivator(hostMethod, IL, skipInterception);

            IL.Emit(OpCodes.Stloc, _currentActivator);

            IL.Emit(OpCodes.Ldloc, _currentActivator);
            IL.Emit(OpCodes.Brfalse, skipInterception);

            // Determine if the activator can instantiate the method from the
            // current context
            IL.Emit(OpCodes.Ldloc, _currentActivator);
            IL.Emit(OpCodes.Ldloc, _methodContext);
            IL.Emit(OpCodes.Callvirt, _canActivate);
            IL.Emit(OpCodes.Brfalse, skipInterception);

            // Use the activator to create the object instance
            EmitCreateInstance(IL);

            // }
            Instruction endCreate = IL.Create(OpCodes.Nop);
            IL.Emit(OpCodes.Br, endCreate);
            // else {
            IL.Append(skipInterception);

            // Restore the arguments that were popped off the stack
            // by the list of constructor arguments
            int parameterCount = parameters.Count;
            for (int index = 0; index < parameterCount; index++)
            {
                ParameterDefinition currentParameter = parameters[index];

                IL.Emit(OpCodes.Ldloc, _constructorArguments);
                IL.Emit(OpCodes.Ldc_I4, index);
                IL.Emit(OpCodes.Callvirt, _getItem);
                IL.Emit(OpCodes.Unbox_Any, currentParameter.ParameterType);
            }

            IL.Emit(OpCodes.Newobj, targetConstructor);
            // }

            IL.Append(endCreate);
        }

        public void Emit(CilWorker IL)
        {
            var module = IL.GetModule();
            var method = IL.GetMethod();

            var getProvider = _resolveGetProviderMethod(module);

            var pushThis = method.HasThis ? OpCodes.Ldarg_0 : OpCodes.Ldnull;
            IL.Emit(pushThis);

            IL.Emit(OpCodes.Ldloc, _invocationInfo);
            IL.Emit(OpCodes.Call, getProvider);
            IL.Emit(OpCodes.Stloc, _classMethodReplacementProvider);
        }

        public void AddEpilog(CilWorker IL)
        {
            var skipEpilog = IL.Create(OpCodes.Nop);

            // if (!IsInterceptionDisabled && surroundingImplementation != null) {
            IL.Emit(OpCodes.Ldloc, _interceptionDisabled);
            IL.Emit(OpCodes.Brtrue, skipEpilog);

            // surroundingImplementation.AfterInvoke(invocationInfo, returnValue);
            var emitAfterInvoke = new EmitAfterInvoke(_surroundingImplementation, _surroundingClassImplementation, _invocationInfo, _returnValue);
            emitAfterInvoke.Emit(IL);

            // }
            IL.Append(skipEpilog);
        }

        /// <summary>
        /// Emits the call to the <see cref="IAfterInvoke"/> instance.
        /// </summary>
        /// <param name="IL">The <see cref="CilWorker"/> that points to the current method body.</param>
        public void Emit(CilWorker IL)
        {
            var targetMethod = IL.GetMethod();
            var declaringType = targetMethod.DeclaringType;
            var module = declaringType.Module;

            var getSurroundingClassImplementation = new GetSurroundingClassImplementation(_invocationInfo,
                _surroundingClassImplementation,
                _registryType.GetMethod(
                    "GetSurroundingImplementation"));

            // var classAroundInvoke = AroundInvokeRegistry.GetSurroundingImplementation(info);
            getSurroundingClassImplementation.Emit(IL);

            // classAroundInvoke.BeforeInvoke(info);
            var skipInvoke = IL.Create(OpCodes.Nop);

            IL.Emit(OpCodes.Ldloc, _surroundingClassImplementation);
            IL.Emit(OpCodes.Brfalse, skipInvoke);

            var beforeInvoke = module.ImportMethod<IBeforeInvoke>("BeforeInvoke");

            // surroundingImplementation.BeforeInvoke(invocationInfo);
            IL.Emit(OpCodes.Ldloc, _surroundingClassImplementation);
            IL.Emit(OpCodes.Ldloc, _invocationInfo);
            IL.Emit(OpCodes.Callvirt, beforeInvoke);

            IL.Append(skipInvoke);

            // if (surroundingImplementation != null) {
            if (!targetMethod.HasThis)
                return;

            var skipInvoke1 = IL.Create(OpCodes.Nop);
            IL.Emit(OpCodes.Ldloc, _surroundingImplementation);
            IL.Emit(OpCodes.Brfalse, skipInvoke1);

            var beforeInvoke1 = module.ImportMethod<IBeforeInvoke>("BeforeInvoke");

            // surroundingImplementation.BeforeInvoke(invocationInfo);
            IL.Emit(OpCodes.Ldloc, _surroundingImplementation);
            IL.Emit(OpCodes.Ldloc, _invocationInfo);
            IL.Emit(OpCodes.Callvirt, beforeInvoke1);

            IL.Append(skipInvoke1);
            // }
        }

        public void Emit(CilWorker IL)
        {
            var method = _hostMethod;
            var declaringType = method.DeclaringType;
            var module = declaringType.Module;

            if (!method.HasThis)
            {
                IL.Emit(OpCodes.Ldnull);
                IL.Emit(OpCodes.Stloc, _methodReplacementProvider);
                return;
            }

            var getProvider = _resolveGetProviderMethod(module);
            IL.Emit(OpCodes.Ldarg_0);
            IL.Emit(OpCodes.Callvirt, getProvider);
            IL.Emit(OpCodes.Stloc, _methodReplacementProvider);
        }

        /// <summary>
        /// Emits the instructions that obtain the <see cref="IMethodReplacementProvider"/> instance.
        /// </summary>
        /// <param name="IL">The <see cref="CilWorker"/> instance.</param>
        public void Emit(CilWorker IL)
        {
            MethodDefinition method = _hostMethod;
            TypeDefinition declaringType = method.DeclaringType;
            ModuleDefinition module = declaringType.Module;

            if (!method.HasThis)
            {
                IL.Emit(OpCodes.Ldnull);
                IL.Emit(OpCodes.Stloc, _methodReplacementProvider);
                return;
            }

            MethodReference getProvider = _resolveGetProviderMethod(module);
            IL.Emit(OpCodes.Ldarg_0);
            IL.Emit(OpCodes.Callvirt, getProvider);
            IL.Emit(OpCodes.Stloc, _methodReplacementProvider);
        }

        public void Emit(CilWorker IL)
        {
            var method = IL.GetMethod();
            var module = IL.GetModule();

            // var aroundInvokeProvider = this.AroundInvokeProvider;
            var getAroundInvokeProvider = module.ImportMethod<IModifiableType>("get_AroundInvokeProvider");

            if (!method.HasThis)
            {
                IL.Emit(OpCodes.Ldnull);
                IL.Emit(OpCodes.Stloc, _aroundInvokeProvider);
                return;
            }

            IL.Emit(OpCodes.Ldarg_0);
            IL.Emit(OpCodes.Callvirt, getAroundInvokeProvider);
            IL.Emit(OpCodes.Stloc, _aroundInvokeProvider);
        }

        /// <summary>
        /// Emits the call to obtain the <see cref="IAroundInvokeProvider"/> instance.
        /// </summary>
        /// <param name="IL">The <see cref="CilWorker"/> pointing to the target method body.</param>
        public void Emit(CilWorker IL)
        {
            MethodDefinition method = IL.GetMethod();
            ModuleDefinition module = IL.GetModule();

            // var aroundInvokeProvider = this.AroundInvokeProvider;
            string propertyName = string.Format("get_{0}", _providerName);
            MethodReference getAroundInvokeProvider = module.ImportMethod<IAroundInvokeHost>(propertyName);

            if (!method.HasThis)
            {
                IL.Emit(OpCodes.Ldnull);
                IL.Emit(OpCodes.Stloc, _aroundInvokeProvider);
                return;
            }

            IL.Emit(OpCodes.Ldarg_0);
            IL.Emit(OpCodes.Callvirt, getAroundInvokeProvider);
            IL.Emit(OpCodes.Stloc, _aroundInvokeProvider);
        }

        public void Emit(CilWorker IL)
        {
            var module = IL.GetModule();
            var method = IL.GetMethod();
            var returnType = method.ReturnType.ReturnType;
            var methodReplacement = MethodDefinitionExtensions.AddLocal(method, typeof(IInterceptor));

            GetMethodReplacementInstance(method, IL, methodReplacement, _methodReplacementProvider, _invocationInfo);

            var skipGetClassMethodReplacement = IL.Create(OpCodes.Nop);
            IL.Emit(OpCodes.Ldloc, methodReplacement);
            IL.Emit(OpCodes.Brtrue, skipGetClassMethodReplacement);

            GetMethodReplacementInstance(method, IL, methodReplacement, _classMethodReplacementProvider, _invocationInfo);

            IL.Append(skipGetClassMethodReplacement);
            IL.Emit(OpCodes.Ldloc, methodReplacement);
            IL.Emit(OpCodes.Brfalse, _executeOriginalInstructions);

            // var returnValue = replacement.Intercept(info);
            InvokeInterceptor(module, IL, methodReplacement, returnType, _invocationInfo);
        }

        /// <summary>
        /// Adds method body interception to the target method.
        /// </summary>
        /// <param name="IL">The <see cref="CilWorker"/> pointing to the target method body.</param>
        public void Emit(CilWorker IL)
        {
            MethodDefinition method = IL.GetMethod();
            TypeReference returnType = method.ReturnType.ReturnType;

            Instruction endLabel = IL.Create(OpCodes.Nop);
            Instruction executeOriginalInstructions = IL.Create(OpCodes.Nop);

            // Execute the method body replacement if and only if
            // interception is enabled
            IL.Emit(OpCodes.Ldloc, _interceptionDisabled);
            IL.Emit(OpCodes.Brtrue, executeOriginalInstructions);

            Instruction invokeReplacement = IL.Create(OpCodes.Nop);

            IL.Emit(OpCodes.Ldloc, _methodReplacementProvider);
            IL.Emit(OpCodes.Brtrue, invokeReplacement);

            IL.Emit(OpCodes.Ldloc, _classMethodReplacementProvider);
            IL.Emit(OpCodes.Brtrue, invokeReplacement);

            IL.Emit(OpCodes.Br, executeOriginalInstructions);
            IL.Append(invokeReplacement);

            // This is equivalent to the following code:
            // var replacement = provider.GetMethodReplacement(info);
            var invokeMethodReplacement = new InvokeMethodReplacement(executeOriginalInstructions,
                                                                      _methodReplacementProvider,
                                                                      _classMethodReplacementProvider, _invocationInfo);
            invokeMethodReplacement.Emit(IL);

            IL.Emit(OpCodes.Br, endLabel);

            #region The original instruction block

            IL.Append(executeOriginalInstructions);
            var addOriginalInstructions = new AddOriginalInstructions(_oldInstructions, endLabel);
            addOriginalInstructions.Emit(IL);

            #endregion

            // Mark the end of the method body
            IL.Append(endLabel);

            var saveReturnValue = new SaveReturnValue(returnType, _returnValue);
            saveReturnValue.Emit(IL);
        }

        public void Emit(CilWorker IL)
        {
            var module = IL.GetModule();

            IL.Emit(OpCodes.Ldloc, _aroundInvokeProvider);
            IL.Emit(OpCodes.Brfalse, _skipGetSurroundingImplementation);

            // var surroundingImplementation = this.GetSurroundingImplementation(this, invocationInfo);
            var getSurroundingImplementation = module.ImportMethod<IAroundInvokeProvider>("GetSurroundingImplementation");
            IL.Emit(OpCodes.Ldloc, _aroundInvokeProvider);
            IL.Emit(OpCodes.Ldloc, _invocationInfo);
            IL.Emit(OpCodes.Callvirt, getSurroundingImplementation);
            IL.Emit(OpCodes.Stloc, _surroundingImplementation);
        }

        private static void Emit(CilWorker IL, ModuleDefinition module,
                                 VariableDefinition surroundingImplementation,
                                 VariableDefinition invocationInfo,
                                 VariableDefinition returnValue)
        {
            Instruction skipInvoke = IL.Create(OpCodes.Nop);

            Instruction skipPrint = IL.Create(OpCodes.Nop);
            IL.Emit(OpCodes.Ldloc, surroundingImplementation);
            IL.Emit(OpCodes.Brtrue, skipPrint);

            IL.Append(skipPrint);
            IL.Emit(OpCodes.Ldloc, surroundingImplementation);
            IL.Emit(OpCodes.Brfalse, skipInvoke);

            MethodReference aroundInvoke = module.ImportMethod<IAfterInvoke>("AfterInvoke");
            IL.Emit(OpCodes.Ldloc, surroundingImplementation);
            IL.Emit(OpCodes.Ldloc, invocationInfo);
            IL.Emit(OpCodes.Ldloc, returnValue);
            IL.Emit(OpCodes.Callvirt, aroundInvoke);

            IL.Append(skipInvoke);
        }