/// <summary>
/// Returns a <see cref="SwiftHandle"/> bridging the given object to Swift.
/// </summary>
/// <remarks>
/// The returned <see cref="SwiftHandle"/> must be disposed when no longer needed.
/// </remarks>
/// <param name="obj">The managed object to bridge to Swift</param>
/// <param name="nullability">Determines whether to bridge the value to Swift
/// as an Optional value. If <typeparamref name="T"/> is identified as a known
/// nullable wrapper, such as <see cref="Nullable"/>, then the value is bridged
/// as an Optional regardless of the value of this parameter.</param>
/// <exception cref="ArgumentNullException">Thrown when <paramref name="obj"/> is
/// <c>null</c>, <typeparamref name="T"/> is not a known nullable wrapper type,
/// and <paramref name="nullability"/> returns <c>false</c> from <see cref="Nullability.IsNullable"/>.</exception>
/// <exception cref="ArgumentException">Thrown when the type <typeparamref name="T"/> cannot
/// be directly bridged to Swift</exception>
public static unsafe SwiftHandle GetSwiftHandle <T> (this T obj, Nullability nullability = default)
{
var type = typeof(T);
var swiftType = SwiftType.Of(type, nullability);
if (swiftType == null && obj != null)
{
type = obj.GetType();
swiftType = SwiftType.Of(type, nullability);
}
if (swiftType == null)
{
throw new ArgumentException($"Type '{type}' cannot be bridged to Swift");
}
// Nullable types are bridged to Swift optionals
if (nullability.IsNullable || Nullability.IsReifiedNullable(type))
{
if (Nullability.IsNull(obj))
{
var underlyingType = Nullability.GetUnderlyingType(type);
var underlyingSwiftType = SwiftType.Of(underlyingType, nullability.Strip()) !;
return(Optional.Wrap(null, swiftType, underlyingSwiftType));
}
else
{
var unwrapped = Nullability.Unwrap(obj);
using (var unwrappedHandle = unwrapped.GetSwiftHandle(nullability.Strip()))
return(Optional.Wrap(unwrappedHandle.Pointer, swiftType, unwrappedHandle.SwiftType));
}
}
else if (obj is null)
{
throw new ArgumentNullException(nameof(obj));
}
return(obj switch {
ISwiftValue swiftValue => swiftValue.GetSwiftHandle(),
string val => new SwiftHandle(new Swift.String(val), swiftType, destroyOnDispose: true),
_ when type.IsPrimitive => new SwiftHandle(obj, swiftType),
_ => throw new NotImplementedException(type.ToString())
});
