///
/// Determines if the candidate method is applicable (section 14.4.2.1)
/// to the given set of arguments
/// A return value rates candidate method compatibility,
/// 0 = the best, int.MaxValue = the worst
///
public int IsApplicable(ResolveContext ec,
ref Arguments arguments, int arg_count, ref MethodSpec method, ref bool params_expanded_form)
{
var candidate = method;
AParametersCollection pd = candidate.Parameters;
int param_count = GetApplicableParametersCount (candidate, pd);
int optional_count = 0;
if (arg_count != param_count) {
for (int i = 0; i < pd.Count; ++i) {
if (pd.FixedParameters [i].HasDefaultValue) {
optional_count = pd.Count - i;
break;
}
}
int args_gap = System.Math.Abs (arg_count - param_count);
if (optional_count != 0) {
if (args_gap > optional_count)
return int.MaxValue - 10000 + args_gap - optional_count;
// Readjust expected number when params used
if (pd.HasParams) {
optional_count--;
if (arg_count < param_count)
param_count--;
} else if (arg_count > param_count) {
return int.MaxValue - 10000 + args_gap;
}
} else if (arg_count != param_count) {
if (!pd.HasParams)
return int.MaxValue - 10000 + args_gap;
if (arg_count < param_count - 1)
return int.MaxValue - 10000 + args_gap;
}
// Initialize expanded form of a method with 1 params parameter
params_expanded_form = param_count == 1 && pd.HasParams;
// Resize to fit optional arguments
if (optional_count != 0) {
Arguments resized;
if (arguments == null) {
resized = new Arguments (optional_count);
} else {
resized = new Arguments (param_count);
resized.AddRange (arguments);
}
for (int i = arg_count; i < param_count; ++i)
resized.Add (null);
arguments = resized;
}
}
if (arg_count > 0) {
//
// Shuffle named arguments to the right positions if there are any
//
if (arguments [arg_count - 1] is NamedArgument) {
arg_count = arguments.Count;
for (int i = 0; i < arg_count; ++i) {
bool arg_moved = false;
while (true) {
NamedArgument na = arguments[i] as NamedArgument;
if (na == null)
break;
int index = pd.GetParameterIndexByName (na.Name);
// Named parameter not found or already reordered
if (index <= i)
break;
// When using parameters which should not be available to the user
if (index >= param_count)
break;
if (!arg_moved) {
arguments.MarkReorderedArgument (na);
arg_moved = true;
}
Argument temp = arguments[index];
arguments[index] = arguments[i];
arguments[i] = temp;
if (temp == null)
break;
}
}
} else {
arg_count = arguments.Count;
}
} else if (arguments != null) {
arg_count = arguments.Count;
}
//
// 1. Handle generic method using type arguments when specified or type inference
//
if (candidate.IsGeneric) {
if (type_arguments != null) {
var g_args_count = candidate.Arity;
if (g_args_count != type_arguments.Count)
return int.MaxValue - 20000 + System.Math.Abs (type_arguments.Count - g_args_count);
method = candidate.MakeGenericMethod (type_arguments.Arguments);
candidate = method;
pd = candidate.Parameters;
} else {
int score = TypeManager.InferTypeArguments (ec, arguments, ref candidate);
if (score != 0)
return score - 20000;
pd = candidate.Parameters;
}
} else {
if (type_arguments != null)
return int.MaxValue - 15000;
}
//
// 2. Each argument has to be implicitly convertible to method parameter
//
method = candidate;
Parameter.Modifier p_mod = 0;
TypeSpec pt = null;
for (int i = 0; i < arg_count; i++) {
Argument a = arguments [i];
if (a == null) {
if (!pd.FixedParameters [i].HasDefaultValue)
throw new InternalErrorException ();
Expression e = pd.FixedParameters [i].DefaultValue as Constant;
if (e == null)
e = new DefaultValueExpression (new TypeExpression (pd.Types [i], loc), loc).Resolve (ec);
arguments [i] = new Argument (e, Argument.AType.Default);
continue;
}
if (p_mod != Parameter.Modifier.PARAMS) {
p_mod = pd.FixedParameters [i].ModFlags & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
pt = pd.Types [i];
} else {
params_expanded_form = true;
}
Parameter.Modifier a_mod = a.Modifier & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
int score = 1;
if (!params_expanded_form)
score = IsArgumentCompatible (ec, a_mod, a, p_mod & ~Parameter.Modifier.PARAMS, pt);
if (score != 0 && (p_mod & Parameter.Modifier.PARAMS) != 0 && delegate_type == null) {
// It can be applicable in expanded form
score = IsArgumentCompatible (ec, a_mod, a, 0, TypeManager.GetElementType (pt));
if (score == 0)
params_expanded_form = true;
}
if (score != 0) {
if (params_expanded_form)
++score;
return (arg_count - i) * 2 + score;
}
}
if (arg_count != param_count)
params_expanded_form = true;
return 0;
}
