public static String CheckAddLongPathPrefix([NotNull] this String path)
{
path = path.ThrowIfBlank();
if (path.StartsWith(LongPathPrefix))
{
return(path);
}
var maxPathLimit = NativeMethods.MAX_PATH;
if (Uri.TryCreate(path.ThrowIfBlank(), UriKind.Absolute, out var uri) && uri.IsUnc)
{
// What's going on here? Empirical evidence shows that Windows has trouble dealing with UNC paths
// longer than MAX_PATH *minus* the length of the "\\hostname\" prefix. See the following tests:
// - UncDirectoryTests.TestDirectoryCreateNearMaxPathLimit
// - UncDirectoryTests.TestDirectoryEnumerateDirectoriesNearMaxPathLimit
var rootPathLength = 3 + uri.Host.Length;
maxPathLimit -= rootPathLength;
}
if (path.Length < maxPathLimit)
{
return(path);
}
return(path.AddLongPathPrefix());
}
