/// <summary>
/// Compares the order of using directives in two lists. Returns null if they are
/// the same, and otherwise returns a description of the first element to move
/// to bring the current order closer into line with the required order.
/// </summary>
/// <param name="requiredOrder">The order in which the directives should appear.</param>
/// <param name="currentOrder">The order in which the directives currently appear.</param>
/// <returns>Null if the orders match. Otherwise, a <see cref="Relocation"/> describing
/// the first element to move to bring the order closer to the required one.</returns>
/// <remarks>
/// Code that simply needs to know whether the order is correct (e.g., when we want to
/// highlight bad ordering) will just use this to get a yes/no answer. Code that wants
/// to fix the order will call this repeatedly to generate a sequence of moves.
/// </remarks>
public static Relocation GetNextUsingToMove(
IEnumerable <UsingDirective> requiredOrder, IEnumerable <UsingDirective> currentOrder)
{
int expectedIndex = 0;
using (var reqIt = requiredOrder.GetEnumerator())
using (var currentIt = currentOrder.GetEnumerator())
{
while (reqIt.MoveNext() && currentIt.MoveNext())
{
UsingDirective expected = reqIt.Current;
if (!ReferenceEquals(expected, currentIt.Current))
{
int currentIndex = expectedIndex;
while (currentIt.MoveNext())
{
currentIndex += 1;
if (ReferenceEquals(expected, currentIt.Current))
{
return(new Relocation(currentIndex, expectedIndex));
}
}
throw new ArgumentException(
"Lists should contain same items, but currentOrder was missing " + expected,
"currentOrder");
}
expectedIndex += 1;
}
}
return(null);
}
public void ReturnsNull()
{
var d1 = new UsingDirective { Namespace = "System" };
var d2 = new UsingDirective { Namespace = "System.Linq" };
var required = new[] { d1, d2 };
var current = new[] { d1, d2 };
Assert.IsNull(OrderChecker.GetNextUsingToMove(required, current));
}
/// <summary>
/// Initialises a <see cref="UsingDirectiveOrSpace"/> representing
/// a using directive. (Use the no-arguments constructor to represent
/// a blank line.)
/// </summary>
/// <param name="directive">The directive.</param>
public UsingDirectiveOrSpace(UsingDirective directive)
{
_directive = directive;
}
/// <summary>
/// Initialises a <see cref="UsingDirectiveOrSpace"/> representing
/// a using directive. (Use the no-arguments constructor to represent
/// a blank line.)
/// </summary>
/// <param name="directive">The directive.</param>
public UsingDirectiveOrSpace(UsingDirective directive)
{
_directive = directive;
}