/// <summary>
/// Validates a specified name according to the GraphQL <see href="http://spec.graphql.org/June2018/#sec-Names">specification</see>.
/// </summary>
/// <param name="name">GraphQL name.</param>
/// <param name="type">Type of element: field, type, argument, enum or directive.</param>
public static void ValidateDefault(string name, NamedElement type)
{
ValidateNameNotNull(name, type);
if (name.Length > 1 && name[0] == '_' && name[1] == '_')
{
throw new ArgumentOutOfRangeException(nameof(name),
$"A {type.ToString().ToLower()} name: '{name}' must not begin with __, which is reserved by GraphQL introspection.");
}
var c = name[0];
if ((c < 'a' || c > 'z') && (c < 'A' || c > 'Z') && c != '_')
{
ThrowMatchError();
}
for (int i = 1; i < name.Length; ++i)
{
c = name[i];
if ((c < 'a' || c > 'z') && (c < 'A' || c > 'Z') && (c < '0' || c > '9') && c != '_')
{
ThrowMatchError();
}
}
void ThrowMatchError()
{
throw new ArgumentOutOfRangeException(nameof(name),
$"A {type.ToString().ToLower()} name must match /^[_a-zA-Z][_a-zA-Z0-9]*$/ but '{name}' does not.");
}
}
//TODO: maybe remove after
internal static void ValidateNameNotNull(string name, NamedElement type)
{
if (string.IsNullOrWhiteSpace(name))
{
throw new ArgumentOutOfRangeException(nameof(name),
$"A {type.ToString().ToLower()} name can not be null or empty.");
}
}
