/// <summary>
/// Returns a ReadOnlyEnumerableOfT that is the result of <paramref name="source"/> plus <paramref name="item"/>.
/// </summary>
/// <typeparam name="T">The element type of the enumerable.</typeparam>
/// <param name="source">The source enumerable to concat.</param>
/// <param name="collectionName">The name of the collection to report in case there's an error.</param>
/// <param name="item">Item to concat to the source enumerable.</param>
/// <returns>Returns a ReadOnlyEnumerableOfT that is the result of <paramref name="source"/> plus <paramref name="item"/>.</returns>
internal static ReadOnlyEnumerable <T> ConcatToReadOnlyEnumerable <T>(this IEnumerable <T> source, string collectionName, T item)
{
ReadOnlyEnumerable <T> readOnlyEnumerable = source.GetOrCreateReadOnlyEnumerable(collectionName);
readOnlyEnumerable.AddToSourceList(item);
return(readOnlyEnumerable);
}
/// <summary>
/// Casts an IEnumerableOfT to ReadOnlyEnumerableOfT.
/// </summary>
/// <typeparam name="T">The element type of the enumerable.</typeparam>
/// <param name="source">The source enumerable.</param>
/// <param name="collectionName">The name of the collection to report in case there's an error.</param>
/// <returns>The casted ReadOnlyEnumerableOfT.</returns>
internal static ReadOnlyEnumerable <T> ToReadOnlyEnumerable <T>(this IEnumerable <T> source, string collectionName)
{
Debug.Assert(!String.IsNullOrEmpty(collectionName), "!string.IsNullOrEmpty(collectionName)");
ReadOnlyEnumerable <T> readonlyCollection = source as ReadOnlyEnumerable <T>;
if (readonlyCollection == null)
{
throw new ODataException(Strings.ReaderUtils_EnumerableModified(collectionName));
}
return(readonlyCollection);
}
/// <summary>
/// true if <paramref name="source"/> is the same instance as ReadOnlyEnumerableOfT.Empty(). false otherwise.
/// </summary>
/// <typeparam name="T">The element type of the enumerable.</typeparam>
/// <param name="source">The enumerable in question.</param>
/// <returns>Returns true if <paramref name="source"/> is the empty ReadOnlyEnumerableOfT. false otherwise.</returns>
internal static bool IsEmptyReadOnlyEnumerable <T>(this IEnumerable <T> source)
{
return(ReferenceEquals(source, ReadOnlyEnumerable <T> .Empty()));
}