LocalBuilder DefineFallbackDelegate(TypeBuilder typeBuilder, MethodBuilder methodBuilder, ILGenerator iLGenerator, Type serviceType, MethodInfo method)
{
Type delegateType;
if (method.ReturnType == null || method.ReturnType == typeof(void))
{
delegateType = typeof(Action);
}
else
{
delegateType = typeof(Func <>).MakeGenericType(method.ReturnType);
}
int bindingFlagsValue = 0;
foreach (BindingFlags item in Enum.GetValues(typeof(BindingFlags)))
{
bindingFlagsValue += item.GetHashCode();
}
var delegateConstructor = delegateType.GetConstructors((BindingFlags)bindingFlagsValue)[0];
LocalBuilder invokeDelegate = iLGenerator.DeclareLocal(delegateType);
// if has parameters
if (method.GetParameters().Length > 0)
{
var anonymousMethodClassTypeBuild = FallbackProxyAnonymousMethodClassBuilder.BuildType(_dynamicAssembly.ModuleBuilder, serviceType, method);
// new anonymousMethodClass
LocalBuilder anonymousMethodClass = iLGenerator.DeclareLocal(anonymousMethodClassTypeBuild.Item1);
//field
iLGenerator.Emit(OpCodes.Ldarg_0); //this
iLGenerator.Emit(OpCodes.Call, typeBuilder.BaseType.GetProperty("Fallback").GetMethod); //.Fallback
for (int i = 1; i <= method.GetParameters().Length; i++)
{
iLGenerator.Emit(OpCodes.Ldarg_S, i);
}
iLGenerator.Emit(OpCodes.Newobj, anonymousMethodClassTypeBuild.Item2);
iLGenerator.Emit(OpCodes.Stloc, anonymousMethodClass);
iLGenerator.Emit(OpCodes.Ldloc, anonymousMethodClass);
iLGenerator.Emit(OpCodes.Ldftn, anonymousMethodClassTypeBuild.Item3);
}
else
{
iLGenerator.Emit(OpCodes.Ldarg_0); //this
iLGenerator.Emit(OpCodes.Call, typeBuilder.BaseType.GetProperty("Fallback").GetMethod); //.Fallback
iLGenerator.Emit(OpCodes.Ldftn, method);
}
iLGenerator.Emit(OpCodes.Newobj, delegateConstructor);
iLGenerator.Emit(OpCodes.Stloc, invokeDelegate);
return(invokeDelegate);
}
public FallbackFeignClientHttpProxyEmitMethodBuilder(DynamicAssembly dynamicAssembly)
{
_dynamicAssembly = dynamicAssembly;
_fallbackProxyAnonymousMethodClassBuilder = new FallbackProxyAnonymousMethodClassBuilder();
}