private static bool IsBaseFinalizeCalled(MethodDefinition finalizer)
{
if (!OpCodeBitmask.Calls.Intersect(OpCodeEngine.GetBitmask(finalizer)))
{
return(false);
}
foreach (Instruction current in finalizer.Body.Instructions)
{
switch (current.OpCode.Code)
{
case Code.Call:
case Code.Callvirt:
MethodReference mr = (current.Operand as MethodReference);
if ((mr != null) && mr.IsFinalizer())
{
return(true);
}
break;
}
}
return(false);
}
public RuleResult CheckType(TypeDefinition type)
{
// rule applies only to type with a finalizer
MethodDefinition finalizer = type.GetMethod(MethodSignatures.Finalize);
if (finalizer == null)
{
return(RuleResult.DoesNotApply);
}
// rule applies
// finalizer is present, look if it has any code within it
// i.e. look if is does anything else than calling it's base class
int nullify_fields = 0;
foreach (Instruction ins in finalizer.Body.Instructions)
{
switch (ins.OpCode.Code)
{
case Code.Call:
case Code.Callvirt:
// it's empty if we're calling the base class finalizer
MethodReference mr = (ins.Operand as MethodReference);
if ((mr == null) || !mr.IsFinalizer())
{
return(RuleResult.Success);
}
break;
case Code.Nop:
case Code.Leave:
case Code.Leave_S:
case Code.Ldarg_0:
case Code.Endfinally:
case Code.Ret:
case Code.Ldnull:
// ignore
break;
case Code.Stfld:
// considered as empty as long as it's only to nullify them
if (ins.Previous.OpCode.Code == Code.Ldnull)
{
nullify_fields++;
continue;
}
return(RuleResult.Success);
default:
// finalizer isn't empty (normal)
return(RuleResult.Success);
}
}
// finalizer is empty (bad / useless)
string msg = nullify_fields == 0 ? String.Empty :
String.Format(CultureInfo.InvariantCulture,
"Contains {0} fields being nullified needlessly", nullify_fields);
Runner.Report(type, Severity.Medium, Confidence.Normal, msg);
return(RuleResult.Failure);
}