using System;

using System.Collections;

namespace Python.Runtime

{

/// <summary>

/// Implements a generic Python iterator for IEnumerable objects and

/// managed array objects. This supports 'for i in object:' in Python.

/// </summary>

internal class Iterator : ExtensionType

{

private readonly IEnumerator iter;

private readonly Type elemType;

public Iterator(IEnumerator e, Type elemType)

{

iter = e;

this.elemType = elemType;

}

/// <summary>

/// Implements support for the Python iteration protocol.

/// </summary>

public static NewReference tp_iternext(BorrowedReference ob)

{

var self = (Iterator)GetManagedObject(ob)!;

try

{

if (!self.iter.MoveNext())

{

Exceptions.SetError(Exceptions.StopIteration, Runtime.PyNone);

return default;

}

}

catch (Exception e)

{

if (e.InnerException != null)

{

e = e.InnerException;

}

Exceptions.SetError(e);

return default;

}

// Current and the conversion can both throw - the latter for a type

// refused by an IClrTypeFilter - and must not unwind through Python

try

{

object item = self.iter.Current;

return Converter.ToPython(item, self.elemType);

}

catch (Exception e)

{

Exceptions.SetError(e);

return default;

}

}

public static NewReference tp_iter(BorrowedReference ob) => new (ob);

}

}