/// <summary>
/// Write a DynamicMethod call by creating and injecting a custom delegate in the proxyType
/// </summary>
/// <param name="il">LazyILGenerator instance</param>
/// <param name="dynamicMethod">Dynamic method to get called</param>
/// <param name="proxyType">ProxyType builder</param>
internal static void WriteDynamicMethodCall(this LazyILGenerator il, DynamicMethod dynamicMethod, TypeBuilder proxyType)
{
// We create a custom delegate inside the module builder
CreateDelegateTypeFor(proxyType, dynamicMethod, out Type delegateType, out MethodInfo invokeMethod);
int index;
lock (_dynamicMethods)
{
_dynamicMethods.Add(dynamicMethod);
index = _dynamicMethods.Count - 1;
}
// We fill the DelegateCache<> for that custom type with the delegate instance
MethodInfo fillDelegateMethodInfo = typeof(DuckType.DelegateCache <>).MakeGenericType(delegateType).GetMethod("FillDelegate", BindingFlags.NonPublic | BindingFlags.Static);
fillDelegateMethodInfo.Invoke(null, new object[] { index });
// We get the delegate instance and load it in to the stack before the parameters (at the begining of the IL body)
il.SetOffset(0);
il.EmitCall(OpCodes.Call, typeof(DuckType.DelegateCache <>).MakeGenericType(delegateType).GetMethod("GetDelegate"), null);
il.ResetOffset();
// We emit the call to the delegate invoke method.
il.EmitCall(OpCodes.Callvirt, invokeMethod, null);
}
private static MethodBuilder GetFieldSetMethod(TypeBuilder proxyTypeBuilder, Type targetType, MemberInfo proxyMember, FieldInfo targetField, FieldInfo instanceField)
{
string proxyMemberName = proxyMember.Name;
Type proxyMemberReturnType = proxyMember is PropertyInfo pinfo ? pinfo.PropertyType : proxyMember is FieldInfo finfo ? finfo.FieldType : typeof(object);
MethodBuilder method = proxyTypeBuilder.DefineMethod(
"set_" + proxyMemberName,
MethodAttributes.Public | MethodAttributes.SpecialName | MethodAttributes.Final | MethodAttributes.HideBySig | MethodAttributes.Virtual,
typeof(void),
new[] { proxyMemberReturnType });
LazyILGenerator il = new LazyILGenerator(method.GetILGenerator());
Type currentValueType = proxyMemberReturnType;
// Load instance
if (!targetField.IsStatic)
{
il.Emit(OpCodes.Ldarg_0);
il.Emit(instanceField.FieldType.IsValueType ? OpCodes.Ldflda : OpCodes.Ldfld, instanceField);
}
// Check if the type can be converted of if we need to enable duck chaining
if (NeedsDuckChaining(targetField.FieldType, proxyMemberReturnType))
{
// Load the argument and convert it to Duck type
il.Emit(OpCodes.Ldarg_1);
il.WriteTypeConversion(proxyMemberReturnType, typeof(IDuckType));
// Call IDuckType.Instance property to get the actual value
il.EmitCall(OpCodes.Callvirt, DuckTypeInstancePropertyInfo.GetMethod, null);
currentValueType = typeof(object);
}
else
{
// Load the value into the stack
il.Emit(OpCodes.Ldarg_1);
}
// We set the field value
if (UseDirectAccessTo(proxyTypeBuilder, targetType) && targetField.IsPublic)
{
// If the instance and the field are public then is easy to set.
il.WriteTypeConversion(currentValueType, targetField.FieldType);
il.Emit(targetField.IsStatic ? OpCodes.Stsfld : OpCodes.Stfld, targetField);
}
else
{
// If the instance or the field are non public we need to create a Dynamic method to overpass the visibility checks
string dynMethodName = $"_setField_{targetField.DeclaringType.Name}_{targetField.Name}";
// Convert the field type for the dynamic method
Type dynValueType = UseDirectAccessTo(proxyTypeBuilder, targetField.FieldType) ? targetField.FieldType : typeof(object);
il.WriteTypeConversion(currentValueType, dynValueType);
// Create dynamic method
Type[] dynParameters = targetField.IsStatic ? new[] { dynValueType } : new[] { typeof(object), dynValueType };
DynamicMethod dynMethod = new DynamicMethod(dynMethodName, typeof(void), dynParameters, proxyTypeBuilder.Module, true);
// Write the dynamic method body
LazyILGenerator dynIL = new LazyILGenerator(dynMethod.GetILGenerator());
dynIL.Emit(OpCodes.Ldarg_0);
if (targetField.IsStatic)
{
dynIL.WriteTypeConversion(dynValueType, targetField.FieldType);
dynIL.Emit(OpCodes.Stsfld, targetField);
}
else
{
if (targetField.DeclaringType != typeof(object))
{
dynIL.Emit(OpCodes.Castclass, targetField.DeclaringType);
}
dynIL.Emit(OpCodes.Ldarg_1);
dynIL.WriteTypeConversion(dynValueType, targetField.FieldType);
dynIL.Emit(OpCodes.Stfld, targetField);
}
dynIL.Emit(OpCodes.Ret);
dynIL.Flush();
// Emit the call to the dynamic method
il.WriteDynamicMethodCall(dynMethod, proxyTypeBuilder);
}
il.Emit(OpCodes.Ret);
il.Flush();
_methodBuilderGetToken.Invoke(method, null);
return(method);
}
private static MethodBuilder GetPropertyGetMethod(TypeBuilder proxyTypeBuilder, Type targetType, MemberInfo proxyMember, PropertyInfo targetProperty, FieldInfo instanceField)
{
string proxyMemberName = proxyMember.Name;
Type proxyMemberReturnType = typeof(object);
Type[] proxyParameterTypes = Type.EmptyTypes;
Type[] targetParametersTypes = GetPropertyGetParametersTypes(proxyTypeBuilder, targetProperty, true).ToArray();
if (proxyMember is PropertyInfo proxyProperty)
{
proxyMemberReturnType = proxyProperty.PropertyType;
proxyParameterTypes = GetPropertyGetParametersTypes(proxyTypeBuilder, proxyProperty, true).ToArray();
if (proxyParameterTypes.Length != targetParametersTypes.Length)
{
DuckTypePropertyArgumentsLengthException.Throw(proxyProperty);
}
}
else if (proxyMember is FieldInfo proxyField)
{
proxyMemberReturnType = proxyField.FieldType;
proxyParameterTypes = Type.EmptyTypes;
if (proxyParameterTypes.Length != targetParametersTypes.Length)
{
DuckTypePropertyArgumentsLengthException.Throw(targetProperty);
}
}
MethodBuilder proxyMethod = proxyTypeBuilder.DefineMethod(
"get_" + proxyMemberName,
MethodAttributes.Public | MethodAttributes.SpecialName | MethodAttributes.Final | MethodAttributes.HideBySig | MethodAttributes.Virtual,
proxyMemberReturnType,
proxyParameterTypes);
LazyILGenerator il = new LazyILGenerator(proxyMethod.GetILGenerator());
MethodInfo targetMethod = targetProperty.GetMethod;
Type returnType = targetProperty.PropertyType;
// Load the instance if needed
if (!targetMethod.IsStatic)
{
il.Emit(OpCodes.Ldarg_0);
il.Emit(instanceField.FieldType.IsValueType ? OpCodes.Ldflda : OpCodes.Ldfld, instanceField);
}
// Load the indexer keys to the stack
for (int pIndex = 0; pIndex < proxyParameterTypes.Length; pIndex++)
{
Type proxyParamType = proxyParameterTypes[pIndex];
Type targetParamType = targetParametersTypes[pIndex];
// Check if the type can be converted of if we need to enable duck chaining
if (NeedsDuckChaining(targetParamType, proxyParamType))
{
// Load the argument and cast it as Duck type
il.WriteLoadArgument(pIndex, false);
il.Emit(OpCodes.Castclass, typeof(IDuckType));
// Call IDuckType.Instance property to get the actual value
il.EmitCall(OpCodes.Callvirt, DuckTypeInstancePropertyInfo.GetMethod, null);
targetParamType = typeof(object);
}
else
{
il.WriteLoadArgument(pIndex, false);
}
// If the target parameter type is public or if it's by ref we have to actually use the original target type.
targetParamType = UseDirectAccessTo(proxyTypeBuilder, targetParamType) || targetParamType.IsByRef ? targetParamType : typeof(object);
il.WriteTypeConversion(proxyParamType, targetParamType);
targetParametersTypes[pIndex] = targetParamType;
}
// Call the getter method
if (UseDirectAccessTo(proxyTypeBuilder, targetType))
{
// If the instance is public we can emit directly without any dynamic method
// Method call
if (targetMethod.IsPublic)
{
// We can emit a normal call if we have a public instance with a public property method.
il.EmitCall(targetMethod.IsStatic || instanceField.FieldType.IsValueType ? OpCodes.Call : OpCodes.Callvirt, targetMethod, null);
}
else
{
// In case we have a public instance and a non public property method we can use [Calli] with the function pointer
il.WriteMethodCalli(targetMethod);
}
}
else
{
// If the instance is not public we need to create a Dynamic method to overpass the visibility checks
// we can't access non public types so we have to cast to object type (in the instance object and the return type).
string dynMethodName = $"_getNonPublicProperty_{targetProperty.DeclaringType.Name}_{targetProperty.Name}";
returnType = UseDirectAccessTo(proxyTypeBuilder, targetProperty.PropertyType) ? targetProperty.PropertyType : typeof(object);
// We create the dynamic method
Type[] targetParameters = GetPropertyGetParametersTypes(proxyTypeBuilder, targetProperty, false, !targetMethod.IsStatic).ToArray();
Type[] dynParameters = targetMethod.IsStatic ? targetParametersTypes : (new[] { typeof(object) }).Concat(targetParametersTypes).ToArray();
DynamicMethod dynMethod = new DynamicMethod(dynMethodName, returnType, dynParameters, proxyTypeBuilder.Module, true);
// Emit the dynamic method body
LazyILGenerator dynIL = new LazyILGenerator(dynMethod.GetILGenerator());
if (!targetMethod.IsStatic)
{
dynIL.LoadInstanceArgument(typeof(object), targetProperty.DeclaringType);
}
for (int idx = targetMethod.IsStatic ? 0 : 1; idx < dynParameters.Length; idx++)
{
dynIL.WriteLoadArgument(idx, true);
dynIL.WriteTypeConversion(dynParameters[idx], targetParameters[idx]);
}
dynIL.EmitCall(targetMethod.IsStatic || instanceField.FieldType.IsValueType ? OpCodes.Call : OpCodes.Callvirt, targetMethod, null);
dynIL.WriteTypeConversion(targetProperty.PropertyType, returnType);
dynIL.Emit(OpCodes.Ret);
dynIL.Flush();
// Emit the call to the dynamic method
il.WriteDynamicMethodCall(dynMethod, proxyTypeBuilder);
}
// Handle the return value
// Check if the type can be converted or if we need to enable duck chaining
if (NeedsDuckChaining(targetProperty.PropertyType, proxyMemberReturnType))
{
if (UseDirectAccessTo(proxyTypeBuilder, targetProperty.PropertyType) && targetProperty.PropertyType.IsValueType)
{
il.Emit(OpCodes.Box, targetProperty.PropertyType);
}
// We call DuckType.CreateCache<>.Create()
MethodInfo getProxyMethodInfo = typeof(CreateCache <>)
.MakeGenericType(proxyMemberReturnType).GetMethod("Create");
il.Emit(OpCodes.Call, getProxyMethodInfo);
}
else if (returnType != proxyMemberReturnType)
{
// If the type is not the expected type we try a conversion.
il.WriteTypeConversion(returnType, proxyMemberReturnType);
}
il.Emit(OpCodes.Ret);
il.Flush();
_methodBuilderGetToken.Invoke(proxyMethod, null);
return(proxyMethod);
}