public RuleResult CheckMethod (MethodDefinition method)
{
// catch abstract, pinvoke and icalls - where rule does not apply
if (!method.HasBody)
return RuleResult.DoesNotApply;
// skip methods without parameters
if (!method.HasParameters)
return RuleResult.DoesNotApply;
// rule doesn't apply to virtual, overrides or generated code
// doesn't apply to code referenced by delegates (note: more complex check moved last)
if (method.IsVirtual || method.HasOverrides || method.IsGeneratedCode ())
return RuleResult.DoesNotApply;
// Also EventArgs parameters are often required in method signatures,
// but often not required. Reduce "false positives"(*) for GUI apps
// (*) it's more a "don't report things outside developer's control"
if (method.IsEventCallback () || IsReferencedByDelegate (method))
return RuleResult.DoesNotApply;
// methods with [Conditional] can be empty (not using any parameter) IL-wise but not source-wise, ignore them
if (method.HasCustomAttributes) {
if (method.CustomAttributes.ContainsType ("System.Diagnostics.ConditionalAttribute"))
return RuleResult.DoesNotApply;
}
// rule applies
// we limit ourselves to the first 64 parameters (so we can use a bitmask)
IList<ParameterDefinition> pdc = method.Parameters;
int pcount = pdc.Count;
if (pcount > 64)
pcount = 64;
ulong mask = 0;
// scan IL to see which parameter is being used
foreach (Instruction ins in method.Body.Instructions) {
ParameterDefinition parameter = ins.GetParameter (method);
if (parameter == null)
continue;
mask |= ((ulong)1 << (parameter.GetSequence () - 1));
}
// quick out based on value - i.e. every parameter is being used
int shift = 64 - pcount;
if ((mask << shift) == (UInt64.MaxValue << shift))
return RuleResult.Success;
for (int i = 0; i < pcount; i++) {
if ((mask & ((ulong) 1 << i)) == 0) {
ParameterDefinition parameter = pdc [i];
string text = String.Format ("Parameter '{0}' of type '{1}' is never used in the method.",
parameter.Name, parameter.ParameterType);
Runner.Report (parameter, Severity.Medium, Confidence.Normal, text);
}
}
return Runner.CurrentRuleResult;
}
public RuleResult CheckMethod (MethodDefinition method)
{
if (!method.HasBody || !method.HasParameters || method.IsCompilerControlled)
return RuleResult.DoesNotApply;
if (method.IsProperty () || method.IsGeneratedCode () || method.IsEventCallback ())
return RuleResult.DoesNotApply;
// we cannot change parameter types if:
// - we're overriding a base virtual method; or
// - they were specified by an interface
if (IsSignatureDictated (method))
return RuleResult.DoesNotApply;
int pcount = method.Parameters.Count;
if (pcount > types_least.Length) {
// that should be quite rare (does not happen for mono 2.0 class libs)
types_least = new TypeReference [pcount];
depths_least = new int [pcount];
}
CheckParameters (method);
CheckParametersSpecializationDelta (method);
Array.Clear (types_least, 0, types_least.Length);
Array.Clear (depths_least, 0, depths_least.Length);
return Runner.CurrentRuleResult;
}
public RuleResult CheckMethod (MethodDefinition method)
{
// we only check non static, non virtual methods and not constructors
if (method.IsStatic || method.IsVirtual || method.IsConstructor)
return RuleResult.DoesNotApply;
// we only check methods with a body
if (!method.HasBody)
return RuleResult.DoesNotApply;
// we also don't check event callbacks, as they usually bring a lot of false positive,
// and that developers are tied to their signature
if (method.IsEventCallback ())
return RuleResult.DoesNotApply;
// that aren't compiler generated (e.g. anonymous methods) or generated by a tool (e.g. web services)
if (method.IsGeneratedCode ())
return RuleResult.DoesNotApply;
// methods with [Conditional] can be empty (not using 'this') IL-wise but not source-wise, ignore them
if (method.HasCustomAttributes) {
if (method.HasAttribute ("System.Diagnostics", "ConditionalAttribute"))
return RuleResult.DoesNotApply;
}
// rule applies
// if we find a use of the "this" reference, it's ok
// in most (all?) case "this" is used with the ldarg_0 instruction
if (OpCodeEngine.GetBitmask (method).Get (Code.Ldarg_0))
return RuleResult.Success;
// but it's also valid to have an ldarg with a 0 value operand
foreach (Instruction instr in method.Body.Instructions) {
if (instr.OpCode.Code == Code.Ldarg) {
ParameterDefinition pd = (instr.Operand as ParameterDefinition);
if (pd.Index == -1)
return RuleResult.Success;
}
}
Runner.Report (method, Severity.Low, Confidence.Total);
return RuleResult.Failure;
}
