/// <summary>
/// Bind the given Python instance and arguments to a particular method
/// overload in <see cref="list"/> and return a structure that contains the converted Python
/// instance, converted arguments and the correct method to call.
/// If unsuccessful, may set a Python error.
/// </summary>
/// <param name="inst">The Python target of the method invocation.</param>
/// <param name="args">The Python arguments.</param>
/// <param name="kw">The Python keyword arguments.</param>
/// <param name="info">If not null, only bind to that method.</param>
/// <param name="methodinfo">If not null, additionally attempt to bind to the generic methods in this array by inferring generic type parameters.</param>
/// <returns>A Binding if successful. Otherwise null.</returns>
internal Binding Bind(IntPtr inst, IntPtr args, IntPtr kw, MethodBase info, MethodInfo[] methodinfo)
{
// loop to find match, return invoker w/ or w/o error
MethodBase[] _methods = null;
var kwargDict = new Dictionary <string, IntPtr>();
if (kw != IntPtr.Zero)
{
var pynkwargs = (int)Runtime.PyDict_Size(kw);
IntPtr keylist = Runtime.PyDict_Keys(kw);
IntPtr valueList = Runtime.PyDict_Values(kw);
for (int i = 0; i < pynkwargs; ++i)
{
var keyStr = Runtime.GetManagedString(Runtime.PyList_GetItem(new BorrowedReference(keylist), i));
kwargDict[keyStr] = Runtime.PyList_GetItem(new BorrowedReference(valueList), i).DangerousGetAddress();
}
Runtime.XDecref(keylist);
Runtime.XDecref(valueList);
}
var pynargs = (int)Runtime.PyTuple_Size(args);
var isGeneric = false;
if (info != null)
{
_methods = new MethodBase[1];
_methods.SetValue(info, 0);
}
else
{
_methods = GetMethods();
}
var argMatchedMethods = new List <MatchedMethod>(_methods.Length);
var mismatchedMethods = new List <MismatchedMethod>();
// TODO: Clean up
foreach (MethodBase mi in _methods)
{
if (mi.IsGenericMethod)
{
isGeneric = true;
}
ParameterInfo[] pi = mi.GetParameters();
ArrayList defaultArgList;
bool paramsArray;
int kwargsMatched;
int defaultsNeeded;
bool isOperator = OperatorMethod.IsOperatorMethod(mi);
// Binary operator methods will have 2 CLR args but only one Python arg
// (unary operators will have 1 less each), since Python operator methods are bound.
isOperator = isOperator && pynargs == pi.Length - 1;
bool isReverse = isOperator && OperatorMethod.IsReverse((MethodInfo)mi); // Only cast if isOperator.
if (isReverse && OperatorMethod.IsComparisonOp((MethodInfo)mi))
{
continue; // Comparison operators in Python have no reverse mode.
}
if (!MatchesArgumentCount(pynargs, pi, kwargDict, out paramsArray, out defaultArgList, out kwargsMatched, out defaultsNeeded) && !isOperator)
{
continue;
}
// Preprocessing pi to remove either the first or second argument.
if (isOperator && !isReverse)
{
// The first Python arg is the right operand, while the bound instance is the left.
// We need to skip the first (left operand) CLR argument.
pi = pi.Skip(1).ToArray();
}
else if (isOperator && isReverse)
{
// The first Python arg is the left operand.
// We need to take the first CLR argument.
pi = pi.Take(1).ToArray();
}
int outs;
var margs = TryConvertArguments(pi, paramsArray, args, pynargs, kwargDict, defaultArgList, outs: out outs);
if (margs == null)
{
var mismatchCause = PythonException.FetchCurrent();
mismatchedMethods.Add(new MismatchedMethod(mismatchCause, mi));
continue;
}
if (isOperator)
{
if (inst != IntPtr.Zero)
{
if (ManagedType.GetManagedObject(inst) is CLRObject co)
{
bool isUnary = pynargs == 0;
// Postprocessing to extend margs.
var margsTemp = isUnary ? new object[1] : new object[2];
// If reverse, the bound instance is the right operand.
int boundOperandIndex = isReverse ? 1 : 0;
// If reverse, the passed instance is the left operand.
int passedOperandIndex = isReverse ? 0 : 1;
margsTemp[boundOperandIndex] = co.inst;
if (!isUnary)
{
margsTemp[passedOperandIndex] = margs[0];
}
margs = margsTemp;
}
else
{
continue;
}
}
}
var matchedMethod = new MatchedMethod(kwargsMatched, defaultsNeeded, margs, outs, mi);
argMatchedMethods.Add(matchedMethod);
}
if (argMatchedMethods.Count > 0)
{
var bestKwargMatchCount = argMatchedMethods.Max(x => x.KwargsMatched);
var fewestDefaultsRequired = argMatchedMethods.Where(x => x.KwargsMatched == bestKwargMatchCount).Min(x => x.DefaultsNeeded);
int bestCount = 0;
int bestMatchIndex = -1;
for (int index = 0; index < argMatchedMethods.Count; index++)
{
var testMatch = argMatchedMethods[index];
if (testMatch.DefaultsNeeded == fewestDefaultsRequired && testMatch.KwargsMatched == bestKwargMatchCount)
{
bestCount++;
if (bestMatchIndex == -1)
{
bestMatchIndex = index;
}
}
}
if (bestCount > 1 && fewestDefaultsRequired > 0)
{
// Best effort for determining method to match on gives multiple possible
// matches and we need at least one default argument - bail from this point
StringBuilder stringBuilder = new StringBuilder("Not enough arguments provided to disambiguate the method. Found:");
foreach (var matchedMethod in argMatchedMethods)
{
stringBuilder.AppendLine();
stringBuilder.Append(matchedMethod.Method.ToString());
}
Exceptions.SetError(Exceptions.TypeError, stringBuilder.ToString());
return(null);
}
// If we're here either:
// (a) There is only one best match
// (b) There are multiple best matches but none of them require
// default arguments
// in the case of (a) we're done by default. For (b) regardless of which
// method we choose, all arguments are specified _and_ can be converted
// from python to C# so picking any will suffice
MatchedMethod bestMatch = argMatchedMethods[bestMatchIndex];
var margs = bestMatch.ManagedArgs;
var outs = bestMatch.Outs;
var mi = bestMatch.Method;
object target = null;
if (!mi.IsStatic && inst != IntPtr.Zero)
{
//CLRObject co = (CLRObject)ManagedType.GetManagedObject(inst);
// InvalidCastException: Unable to cast object of type
// 'Python.Runtime.ClassObject' to type 'Python.Runtime.CLRObject'
var co = ManagedType.GetManagedObject(inst) as CLRObject;
// Sanity check: this ensures a graceful exit if someone does
// something intentionally wrong like call a non-static method
// on the class rather than on an instance of the class.
// XXX maybe better to do this before all the other rigmarole.
if (co == null)
{
Exceptions.SetError(Exceptions.TypeError, "Invoked a non-static method with an invalid instance");
return(null);
}
target = co.inst;
}
return(new Binding(mi, target, margs, outs));
}
else if (isGeneric && info == null && methodinfo != null)
{
// We weren't able to find a matching method but at least one
// is a generic method and info is null. That happens when a generic
// method was not called using the [] syntax. Let's introspect the
// type of the arguments and use it to construct the correct method.
Type[] types = Runtime.PythonArgsToTypeArray(args, true);
MethodInfo mi = MatchParameters(methodinfo, types);
if (mi != null)
{
return(Bind(inst, args, kw, mi, null));
}
}
if (mismatchedMethods.Count > 0)
{
var aggregateException = GetAggregateException(mismatchedMethods);
Exceptions.SetError(aggregateException);
}
return(null);
}
