public static void Rewrite(PointCut asyncVoidPc, MethodDefinition asyncVoidMethod, VariableDefinition taskVar)
{
asyncVoidMethod.Body.SimplifyMacros();
var asyncVoidMBType = asyncVoidMethod.Module.Import(typeof(AsyncVoidMethodBuilder));
var asyncTaskMBType = asyncVoidMethod.Module.Import(typeof(AsyncTaskMethodBuilder));
asyncVoidMethod.Body.Variables.First(v => v.VariableType.IsTypeOf(asyncVoidMBType)).VariableType = asyncTaskMBType;
Instruction loadStateMachineInst = null;
FieldReference builderField = null;
foreach (var inst in asyncVoidMethod.Body.Instructions)
{
var method = inst.Operand as MethodReference;
if (method != null && method.DeclaringType.IsTypeOf(asyncVoidMBType))
{
var newMethod = asyncVoidMethod.Module.Import(asyncTaskMBType.Resolve().Methods.First(m => m.Name == method.Name));
if (method.IsGenericInstance)
{
newMethod = newMethod.MakeGeneric(newMethod.DeclaringType, ((IGenericInstance)method).GenericArguments.ToArray());
}
inst.Operand = newMethod;
if (method.Name == "Create")
{
loadStateMachineInst = inst.Previous;
builderField = (FieldReference)inst.Next.Operand;
}
}
}
var stateMachine = builderField.DeclaringType.Resolve();
stateMachine.Fields.First(v => v.FieldType.IsTypeOf(asyncVoidMBType)).FieldType = asyncTaskMBType;
foreach (var md in stateMachine.Methods)
{
RewriteMethod(md);
}
var getTask = asyncTaskMBType.Resolve().Properties.First(p => p.Name == "Task").GetMethod;
if (loadStateMachineInst == null || builderField == null)
{
throw new NotSupportedException("Unsupported state machine implementation");
}
asyncVoidPc.SetVariable(taskVar,
c =>
{
c.InsertBefore(c.CreateInstruction(loadStateMachineInst.OpCode, (VariableDefinition)loadStateMachineInst.Operand));
c.InsertBefore(c.CreateInstruction(OpCodes.Ldflda, builderField));
c.InjectMethodCall(getTask);
});
asyncVoidMethod.Body.OptimizeMacros();
}