internal static void EncapsulateMethodBodyWithTryFinallyBlock(this ILProcessor ilProcessor,
Instruction firstInstruction, Action <ILProcessor, Instruction> insertBeforReturn)
{
var body = ilProcessor.Body;
if (body.Method.IsConstructor && !body.Method.IsStatic)
{
var ctor = GetFirstConstructorInstruction(body);
if (ctor != null)
{
if (body.Instructions.IndexOf(ctor) > 2)
{
var lastInstruction = body.Instructions.Last();
var firtLDarg0BeforeCtor = ctor.GetFirstPreviousLdarg_0();
if (firstInstruction != firtLDarg0BeforeCtor)
{
EncapsulateWithTryCatch(ilProcessor, firstInstruction, firtLDarg0BeforeCtor);
}
if (ctor.GetFirstNotNopInstruction().Equals(lastInstruction))
{
insertBeforReturn(ilProcessor, lastInstruction);
return;
}
}
if (firstInstruction.Next.OpCode != OpCodes.Nop)
{
firstInstruction = Instruction.Create(OpCodes.Nop);
ilProcessor.InsertAfter(ctor, firstInstruction);
}
}
}
var returnStart = ilProcessor.FixReturns();
var beforeReturn = Instruction.Create(OpCodes.Endfinally);
ilProcessor.InsertBefore(returnStart, beforeReturn);
if (body.Instructions.First().Equals(firstInstruction))
{
Instruction tryStart = Instruction.Create(OpCodes.Nop);
ilProcessor.InsertBefore(firstInstruction, tryStart);
}
Instruction finallyStart = Instruction.Create(OpCodes.Nop);
ilProcessor.InsertBefore(beforeReturn, finallyStart);
insertBeforReturn(ilProcessor, beforeReturn);
var handler = new ExceptionHandler(ExceptionHandlerType.Finally)
{
TryStart = firstInstruction,
TryEnd = finallyStart,
HandlerStart = finallyStart,
HandlerEnd = returnStart,
};
body.ExceptionHandlers.Add(handler);
}